Digitized by the Internet Archive in 2012 with funding from University of California, Davis Libraries http://archive.org/details/venturacountyinv12cali >o/ AH^t- I STATE OF CALIFORNIA GOODWIN J. KNIGHT GOVERNOR PUBLICATION OF STATE WATER RESOURCES BOARD Bulletin No. 12 VENTURA COUNTY INVESTIGATION Volume I TEXT October, 1953 Revised April, 1956 UNIVERSITY OF CALIFOKMI/ JAN 141957 LIBRARY STATE OF CALIFORNIA GOODWIN J. KNIGHT GOVERNOR PUBLICATION OF STATE WATER RESOURCES BOARD Bulletin No. 12 VENTURA COUNTY INVESTIGATION Volume I TEXT October, 1953 Revised April, 1956 LTBRARY UNIVERSJ n l.IFORNIA DA\ IS TABLE OF CONTENTS Page LETTER OF TRANSMITTAL, STATE WATER RESOURCES BOARD xviii ACKNOWLEDGMENT .'....' . ORGANIZATION, STATE WATER RESOURCES BOARD xx ORGANIZATION, STATE DEPARTMENT OF PUBLIC WORKS, DIVISION OF WATER RESOURCES xxi ORGANIZATION, COUNTY OF VENTURA, VENTURA COUNTY FLOOD CONTROL DISTRICT, BOARD OF SUPERVISORS xxiii CHAPTER I. INTRODUCTION Authorization for Investigation ■ . ■ 1-1 Related Investigations and Reports 1-2 Cooperation With Other Agencies 1-5 Scope of Investigation and Report 1-7 Area Under Investigation . . 1-11 Drainage Basins 1-11 Climate 1-14 Geology 1-14 Soils 1-15 Present Development 1-17 Hydrologic Units ........ 1-19 CHAPTER II. WATER SUPPLY Precipitation 2-4 Precipitation Stations and Records 2-4 Precipitation Characteristics 2-11 Quantity of Precipitation 2-19 TABLE OF CONTENTS (Continued) Page Runoff 2 " 20 Stream Gaging Stations and Records 2-21 Runoff Characteristics 2-25 Quantity of Runoff 2-26 Imported Water. ...........••• 2-31 Underground Hydrology • 2-32 Ventura Hydrologic Unit 2-37 Upper Ojai Basin • • 2-39 Ojai Basin 2-UO Upper Ventura River Basin. • . . • 2-1*2 Lower Ventura River Basin. 2-kl Santa Clara River Hydrologic Unit 2-h9 Piru Basin 2-51-J- Fillmore Basin ........... 2-60 Santa Paula Basin 2-65 Llound Basin 2-70 Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins . 2-73 Calleguas-Conejo Hydrologic Unit ••• 2-87 Simi Basin 2-90 East and West Las Posas Basins 2-93 Conejo Basin ...... • 2-96 Tierra Rejada Basin. .... 2-98 Santa Rosa Basin 2-99 Quality of Water 2-101 Standards of Quality for Water 2-101* Irrigation Use 2-10^ li TABLE OF CONTENTS (Continued) Page . Domestic and Municipal Use 2-108 Industrial Use 2-109 Quality of Surface Water 2-109 Ventura Hydrologic Unit 2-109 Santa Clara River Hydrologic Unit ••*.. 2-110 Calleguas-Conejo Hydrologic Unit •• 2-111 Malibu Hydrologic Unit 2-111 Quality of Ground Water 2-115 Ventura Hydrologic Unit 2-115 Santa Clara River Hydrologic Unit 2-116 Calleguas-Conejo Hydrologic Unit 2-119 Sources of Impairment 2-127 Natural Sources • 2-127 Domestic Sewage •... 2-128 Irrigation Return Water 2-128 Industrial Wastes. 2-129 Sea-Water Intrusion 2-129 Safe Yield of Presently Developed Water Supply 2-137 Ventura Hydrologic Unit 2-139 Upper Ojai Subunit .♦.. 2-lUO Ojai Subunit 2-11*0 Upper and Lower Ventura River Subunits •••• 2-li|0 Rincon Subunit .„ 2-1^2 Santa. Clara River. Hydrologic Unit 2-1U3 Eastern Subunit. ?-lMi Piru, Fillmore, and Santa Paula Subunits ......... 2-lkh in TABLE OF CONTENTS (Continued) Page Mound Subunit 2-ll*6 Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits 2-li;7 Calleguas-Conejo Hydrologic Unit ••••••• 2-153 Simi Subunit 2-15U East and West Las Posas Subunits 2-155 Cone jo Subunit 2-156 Tierra Rejada Subunit 2-156 Santa Rosa Subunit • •• 2-157 Malibu Hydrologic Unit 2-157 CHAPTER III. V/ATER UTILIZATION AND REQUIREMENTS Present Water Supply Development. •• ••••• 3-3 Land Use. 3-10 Past and Present Patterns of Land Use. 3-11 Probable Ultimate Pattern of Land Use. •• 3-21 Unit Use of Water 3-31 Unit Values of Consumptive Use 3-31 Unit Values of Applied Water 3-39 Water Requirements ••• • 3-^2 Present Water Requirements ..- ••• 3-U± Probable Ultimate Water Requirements •• 3-50 Demands for Water . 3-5U Monthly Demands for Water 3-5U Irrigation Efficiency.,.. 3-57 Irrecoverable Losses ...... 3-58 Permissible Deficiencies in Application of Water • • 3-59 iv TABLE OF CONTENTS (Continued) Page Supplemental Water Requirements • 3-5>9 Present Supplemental Water Requirements. 3-60 Probable Ultimate Supplemental Water Requirements. ...... 3-61i Ventura Hydrologic Unit 3-6U Santa Clara River Hydrologic Unit ............ 3-6U Calleguas-Conejo and Malibu Hydrologic Units. ...... 3-67 CHAPTER IV. PLANS FOR WATER SUPPLY DEVELOPMENT Plans for Local Conservation Development U-U Potential Surface Storage Developments ............ U-8 Casitas Dam and Reservoir ••••••• • ii-18 Other Dam and Reservoir Sites Considered ...... I1-I8 Areas and Capacities of Reservoir. k-19 Geology of Dam Site it- 20 Operation and Yield of Reservoir U-22 Design Features of Ventura River-Casitas Diversion • U-30 Design Features of Casitas Dam and Reservoir .... U-3U Summary of Estimated Costs ii-hO Ferndale Dam and Reservoir. h~kl Cold Spring Dam and Reservoir •••••••• h-53 Topatopa Dam and Reservoir U-67 Hammel Dam and Reservoir. •••••••••••••••• h-19 Fillmore Dam and Reservoir. •• • h-90 Upper Blue Point Dam and Reservoir. • • 1^-101 Blue Point Dam and Reservoir li-113 Devil Canyon Dam and Reservoir It-122 Santa Felicia Dam and Reservoir ii-138 v TABLE OF CONTENTS (Continued) Page Conveyance and Distribution .of Supplemental Water ....... Irl^O Distribution System for Casitas Reservoir l*-l£0 Casitas-Oxnard Plain Diversion h-15>5 Santa Clara River Conduit U-157 Oxnard Plain-Pleasant Valley Distribution System ii-lf>9 Piru-Las Posas Diversion .... U-16U Planned Operation of Ground Water Storage i|-l67 Ojai Basin I4.-I68 Piru, Fillmore, and Santa Paula Basins li-170 Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins • li-178 Simi and East and West Las Posas Basins. •••• Ii-l8l Plans for Importation by Means of Feather River Project U-186 Plans for Importation by Means of Metropolitan Water District of Southern California • h-195 Metropolitan Water District of Southern California • • h-195 Conveyance of Imported Water to Ventura County U-199 Terminal Storage • lt-203 Distribution of Colorado River Water in Ventura County U-20U Estimates of Cost . , li-207 Discussion of Alternative Initial Plans for Water Supply Development . I4-21I4 Plan I. .... U-225 Plan IA . . . h-226 Plan II ... i ' . . ii-227 Plan IIA. i li-228 Plan III. U-228 Plan'IIIA ii-229 Comparison of Alternative Plans ..... h-229 vi TABLE OF CONTENTS (Continued) CHAPTER V. SUMMARY OF CONCLUSIONS, AND RECOMMENDATIONS Page Summary of Conclusions 5-1 Recommendations 5-10 APPENDIXES (Appendixes are bound at end of Volume II) A. Agreement, and Its Supplement, Between the State Water Resources Board, the County of Ventura, and the Department of Public Yforks A-l B. Geology and Ground Water of Ventura County, California B-l C» Estimates of Cost C-l D. Some Organizational and Financial Aspects Involved in Implementing Water Plans in Ventura County .... ........ D-l vn TABLES Table No. P*ge 1 Areas of Hydrologic Units and Subunits 1-21 2 Mean, Maximum, and Minimum Seasonal Precipitation at Selected Stations in Ventura County 2-6 3 Recorded and Estimated Seasonal Precipitation and Precipitation Indices at Selected Stations in Ventura County 2-13 4 Mean Monthly Distribution of Precipitation at Santa Paula . . . 2-19 5 Stream Gaging Stations in or Near Ventura County 2-23 6 Estimated Average Monthly Distribution of Natural Runoff of Sespe Creek Near Fillmore, 1936-37 Through 1950-51 2-26 7 Estimated Seasonal Natural Runoff of Selected Streams of Ventura County, 1936-37 Through 1950-51 2-27 8 Measured and Estimated Seasonal Runoff at Key Stream Gaging Stations in or Near Ventura County, 1936-37 Through 1950-51 . 2-29 9 Summary of Selected Ground Water Basin Characteristics in Ventura Hydrologic Unit 2-38 10 Estimated Seasonal Runoff of Ventura River Near Ventura During Base Period, With Present Pattern of Land Use and With Matilija Reservoir in Operation 2-47 11 Summary of Selected Ground Water Basin Characteristics in Santa Clara River Hydrologic Unit 2-52 12 Estimated Seasonal Storage Depletion in Piru Basin During Base Period, With Present Pattern of Land Use 2-59 13 Estimated Seasonal Storage Depletion in Fillmore Basin During Base Period, With Present Pattern of Land Use 2-64 14 Estimated Seasonal Storage Depletion in Santa Paula Basin During Base Period, With Present Pattern of Land Use .... 2-69 15 Estimated Seasonal Storage Depletion in Oxnard Forebay Basin During Base Period, With Present Pattern of Land Use in Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins . . 2-86 16 Summary of Selected Ground Water Basin Characteristics in Calleguas-Conejo Hydrologic Unit 2-88 17 United States Public Health Service Drinking Water Standards, 1946 2-108 viii Table TABLES No- (Continued) 18 Selected Mineral Analyses of Surface Waters in Ventura County . . 2-112 19 Selected Mineral Analyses of Ground Waters in Ventura County . . 2-122 20 Selected Mineral Analyses of Drainage Waters from Semi-Perched Zone in Vicinity of Port Hueneme 2-126 21 Selected Mineral Analyses of Waters from Saline Intruded Wells in Vicinity of Port Hueneme 2-134 22 Estimated Safe Seasonal Yield of Presently Developed Water Supply in Ventura Hydrologic Unit 2-139 23 Estimated Safe Seasonal Yield of Presently Developed Water Supply in Santa Clara River Hydrologic Unit 2-144 24 Estimated Safe Seasonal Yield of Piru, Fillmore, and Santa Paula Ground Water Basins 2-145 25 Estimated Safe Seasonal Yield of Qxnard Forebay, Oxnard Plain, and Pleasant Valley Basins 2-151 26 Estimated Seasonal Outflow from Santa Clara River Hydrologic Unit During Base Period, With Present Method of Operation, and With Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins Operated in Accordance with their Safe Yield 2-152 27 Estimated Safe Seasonal Yield of Presently Developed Water Sup- ply in Calleguas-Conejo Hydrologic Unit 2-154 28 Estimated Safe Seasonal Yield of Simi Ground Water Basin .... 2-155 29 Major Diversions of Surface Water in Ventura County 3-6 30 Dams and Reservoirs in Ventura County 3-8 31 Measured Diversions of Surface Flow to Spreading Grounds in Santa Clara River Hydrologic Unit, During Base Period .... 3-10 32 Present Water Service Areas of Ventura County 3-12 33 Summary of Present Land Use in Hydrologic Units of Ventura County 3-15 34 Gross Area of Irrigated Crops in Major Hydrologic Units of Ventura County, 1931-32 and 1949-50 3-19 35 Land Classification Standards 3-22 36 Classification of Lands in Hydrologic Units of Ventura County . . 3-25 37 Probable Ultimate Pattern of Land Use in Hydrologic Units of Ventura County 3-28 Table TABLES No. (Continued) Page 38 Estimated Unit Values of Mean Seasonal Consumptive Use of Water on Irrigated Lands in Ventura County 3-35 39 Estimated Average Unit Values of Seasonal Consumptive Use of Water on Irrigated Lands During Drought Period in Ventura County 3-36 40 Estimated Unit Values of Seasonal Consumptive Use of Water on Non- Irrigated Lands in Ventura County 3-37 41 Estimated Mean Seasonal Unit Delivery to and Consumptive Use of Water on Urban and Suburban Lands in Ventura County 3-39 42 Estimated Unit Values of Seasonal Application of Irrigation Water on Principal Crops in Ventura County 3-41 43 Estimated Seasonal Utilization of Water in Mound, Oxnard Plain, and Pleasant Valley Subunits from 1944-45 Through 1951-52 .... 3-47 44 Estimated Present Mean and Drought Period Seasonal Water Require- ments in Ventura County 3-49 45 Estimated Probable Ultimate Mean and Drought Period Seasonal Water Water Requirements in Ventura County 3-53 46 Estimated Average Monthly Distribution of Demands for Urban and Irrigation Water in Ventura County 3-56 47 Estimated Present Mean and Drought Period Seasonal Supplemental Water Requirements in Hydrologic Units of Ventura County . . . 3-63 48 Estimated Probable Ultimate Mean and Drought Period Seasonal Supplemental Water Requirements in Hydrologic Units of Ventura County 3-68 49 Estimated Seasonal Waste to the Ocean from Ventura and Santa Clara Rivers During Base Period, With Present Patterns of Land Use and Water Supply Development 4-7 50 Areas and Capacities of Casitas Reservoir 4-20 51 Seasonal Runoff of Coyote Creek at Casitas Dam Site and North Fork of Matilija Creek, and Seasonal Spill from Matilija *• Reservoir, During Base Period 4-23 52 Estimated Seasonal Potential for Diversion of Water from Ventura River to Casitas Reservoir During Base Period, V/ith Matilija Reservoir in Operation and Without Provision for Downstream Rights •. 4-24 53 Estimated Storage Capacities and Net Safe Seasonal Yields of Casitas Reservoir for Ventura River Diversion Conduits of Various Capacities 4-27 Table TABLES No. (Continued) Page 54 Estimated Monthly Inflow to Casitas Reservoir During Base Period With Ventura River Diversion Conduit Capacity 200 Second-Feet . 4-29 55 Estimated Net Safe Seasonal Yields of Casitas Reservoir for Selected Storage Capacities, With 200 Second-Foot Ventura River Diversion Conduit 4-30 56 General Features of Ventura River - Casitas Diversion With Capa- city of 200 Second-Feet 4-33 57 General Features of Four Sizes of Dam and Reservoir at the Casitas Site on Coyote Creek 4-39 58 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at the Casitas Site on Coyote Creek, With Diversion from Ventura River of 200 Second-Foot Capacity 4-40 59 Areas and Capacities of Ferndale Reservoir 4-42 60 Estimated Monthly Runoff of Santa Paula Creek at Ferndale Dam Site During Base Period • 4-45 61 Estimated Net Safe Seasonal Yields of Ferndale Reservoir 4-47 62 General Features of Three Sizes of Dam and Reservoir at the Ferndale Site on Santa Paula Creek 4-51 63 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at the /Ferndale' Site on Santa Paula Creek 4-52 64 Areas and Capacities of Cold Spring Reservoir 4-54 65 Estimated Monthly Runoff of Sespe Creek at Cold Spring Dam Site During Base Period 4-58 66 Estimated Net Safe Seasonal Yields of Cold Spring Reservoir .... 4-60 67 General Features of Four Sizes of Dam and Reservoir at the Cold Spring Site on Sespe Creek 4-65 68 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at the Cold Spring Site on Sespe Creek 4-66 69 Areas and Capacities of Topatopa Reservoir 4-68 70 Estimated Monthly Runoff of Sespe Creek at Topatopa Dam Site During Base Period 4-72 71 Estimated Net Safe Seasonal Yield of Topatopa Reservoir 4-73 72 General Features of Three Sizes of Dam and Reservoir at the Topatopa Site on Sespe Creek 4-77 73 Summary of Costs of Dams, Reservoirs, and Yields of Water at the Topatopa Site on Sespe Creek 4-78 xi Table TABLES No, (Continued) Page lh Areas and Capacities of Hammel Reservoir 1^-80 75 Estimated Monthly Runoff of Sespe Creek at Hammel Dam Site During Base Period ....... .......... ii-83 76 Estimated Net Safe Seasonal Yields of Hammel Reservoir ..•••• U-85 77 General Features of Two Sizes of Dam and Reservoir at the Hammel Site on . Sespe . Creek U-88 78 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at the Hammel Site on Sespe Creek U-89 79 Areas and Capacities of Fillmore Reservoir h-91 80 Estimated Monthly Runoff of Sespe Creek at Fillmore Dam Site During Base Period . h-9$ 81 Estimated Net Safe Seasonal Yields of Fillmore Reservoir U— 97 82 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at Fillmore Site on Sespe Creek • • U-100 83 Areas and Capacities of Upper Blue Point Reservoir li-103 8U Estimated Monthly Runoff of Piru Creek at Upper Blue Point and Blue Dam Sites During Base Period ..... U-106 85 General Features of Dam and Reservoir at the Upper Blue Point Site on Piru Creek, with 50,000 Acre- foot Storage Capacity It- 111 86 Summary of Estimated Costs of Dam, Reservoir, and Yield of Water at the Upper Blue Point Site on Piru Creek, with 50,000 Acre- foot Storage Capacity 1+-H2 87 Areas and Capacities of Blue Point Reservoir U-llU 88 General Features of Dam and Reservoir at the Blue Point Site on Piru Creek, with 50,000 Acre- foot storage Capacity U-120 89 Summary of Estimated Costs of Dam, Reservoir, and Yield of Water at the Blue Point Site on Piru Creek, with 50,000 Acre- foot Storage Capacity h-121 90 Areas and Capacities of Devil Canyon Reservoir U-121; 91 Estimated Monthly Runoff of Piru Creek at Devil Canyon Dam Site During Base Period li-127 92 Estimated Net Safe Seasonal Yields of Devil Canyon Reservoir if Operated Solely for Benefit of Santa Clara River Hydrologic Unit li-129 xii Table TABLES No, (Continued) Page 93 Estimated Seasonal Potential for Diversion of Water from Devil Canyon Reservoir to Calleguas-Conejo Hydrologic Unit During Base Period, With Operation of 150,000 Acre-Foot Reservoir for Joint Benefit of Santa Clara River and Calleguas-Conejo Hydrologic Units 4-130 94 Estimated Net Safe Seasonal Yields of 150,000 Acre- Foot Devil Canyon Reservoir, if Operated for Joint Benefit of Santa Clara River and Calleguas-Conejo Hydrologic Units . 4-131 95 General Features of Two Sizes of Dam and Reservoir at the Devil Canyon Site on Piru Creek 4-135 96 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at the Devil Canyon Site on Piru Creek, With Reservoir Operation Solely for Benefit cf Santa Clara River Hydrologic Unit 4-136 97 Estimated Unit Costs of Yields of Water from 150,000 Acre-Foot Devil Canyon Reservoir, With Reservoir Operation for Joint Benefit of Santa Clara River and Calleguas-Conejo Hydrologic Units 4-137 9# Areas and Capacities of Santa Felicia Reservoir 4-139 99 Estimated Monthly Runoff of Piru Creek at Santa Felicia Dam Site During Base Period 4-142 100 Estimated Net Safe Seasonal Yields of Santa Felicia Reservoir . . 4-144 101 General Features of Three Sizes of Dam and Reservoir at the Santa Felicia Site on Piru Creek 4-14& 102 Summary of Estimated Costs of Dams, Reservoirs, and Yields of Water at Santa Felicia Site on Piru Creek 4-149 Summary of Estimated Costs and Yields of Piru-Las Posas Diversion Conduit 4-166 Estimated Effects on Piru, Fillmore, and Santa Paula Ground Water Basins of Operating Topatopa and Santa Felicia Reservoirs Under the Uniform Release Method During the Base Period, Without Releases to Maintain Historic Ground Water Levels . . 4-173 105 Summary of Analyses of Planned Operation of Fillmore and Santa Paula Ground Water Basins During Base Period, With Present Land Use 4-175 106 Summary of Estimated Capital Costs of Feather River Project and Sacramento-San Joaquin Delta Diversion Projects 4-189 xiii Table TABLES No. (Continued) Page 107 Estimated Back Taxes and Interest Payable By Ventura County if Annexed to Metropolitan Water District of Southern California Between December 1, 1953 and December 1, 1954 * . . . 4-210 108 Summary of Estimated Costs of Ventura County Aqueduct to Connect With System of Metropolitan Water District of Southern California 4-212 109 Summary of Estimated Initial Costs of Distribution Colorado River Water Within Ventura County, With Ventura County Aqueduct of 150 Second-Foot capacity 4-213 110 Yields of Potential Ventura County Reservoirs 4-218 111 Economic Comparison of Potential Ventura County Reservoirs .... 4-219 112 Economic Comparison of Selected Combinations of Potential Reser- voirs on Sespe and Piru Creeks, With Uniform Release Operation. 4-224 113 Estimated Costs and Yields of Water of Alternative Initial Plans for Water Supply Development, Without Planned Operation of Ground Water Storage in Santa Clara River Hydrologic Unit . . 4-231 114 Estimated Costs and Yields of Water of Alternative Initial Plans for Water Supply Development, With Planned Operation of Ground Water Storage in Santa Clara River Hydrologic Unit . , 4-232 115 Comparison of Estimated Costs of Alternative Plans of Water Sup- ply Development, With Selected Interest Rates 4-233 xiv PLATES (Plates 1-U2 are bound- at end of Volume II) Plate No . 1 Location of Ventura County 2 Major Water Districts, 1953 3 Hydrologic Units, 1953 k Lines of Equal Mean Seasonal Precipitation in Inches, 1897-98 through 19U6-U7 5 Recorded Seasonal Precipitation at Ojai 6 Accumulated Departure from Mean Seasonal Precipitation at Ojai 7 Stream Gaging and Water Sampling Stations, 1952 8 Estimated Seasonal Natural Runoff of Sespe Creek near Fillmore 9 Accumulated Departure from Mean Seasonal Natural Runoff of Sespe Creek near Fillmore 10 Areal Geology, 1953 11 Ground Water Basins, 1953 12-A Geologic Sections 12-B Geologic Sections 12-C Geologic Sections 13 Diagrammatic Sketch of Oxnard Plain and Oxnard Forebay Basins lk-A Ventura Hydrologic Unit, Lines of Equal Elevation of Ground Water, Fall of 1936 lli-B Santa Clara River Hydrologic Unit, Lines of Equal Elevation of Ground Water, Fall of 1936 lll-C Calleguas-Conejo and Malibu Hydrologic Units, Lines of Equal Elevation of Ground Water, Fall of 1936 15-A Ventura Hydrologic Unit, Lines of Equal Elevation of Ground Water, Spring of 19U1* 15-B Santa Clara River Hydrologic Unit, Lines of Equal Elevation of Ground Water, Spring of 19U!; 15-C Calleguas-Conejo and Malibu Hydrologic Units, Lines of Equal Elevation of Ground Water, Spring of 19lili xv PLATES Plate No , (Continued) 16-A Ventura Hydrologic Unit, Lines of Equal Elevation of Ground Water, Fall of 1951 16- B Santa Clara River Hydrologic Unit, Lines of Equal Elevation of Ground Water, Fall of 1951 16-C Calleguas-Conejo and Malibu hydrologic Units, Lines of Equal Elevation of Ground Water, Fall of 1951 17-A Ventura Hydrologic Unit, Lines of Equal Depth to Ground Water, Fall of 1951 17-B Santa Clara River Hydrologic Unit, Lines of Equal Depth to Ground Water, Fall of 1951 17-C Calleguas-Conejo and Malibu Hydrologic Units, Lines of Equal Depth to Ground Water, Fall of 1951 18- A Ventura Hydrologic Unit, Lines of Equal Change in Ground Water Elevation, Fall of 1936 to Fall of 1951 18-B Santa Clara River Hydrologic Unit, Lines of Equal Change in Ground Water Elevation, Fall of 1936 to Fall of 1951 18-C Calleguas-Conejo and Malibu Hydrologic Units, Lines of Equal Change in Ground Water Elevation, Fall of 1936 to Fall of 1951 19-A Ventura Hydrologic Unit, Lines of Equal Change in Ground Water Elevation, Spring of 19hh to Fall of 1951 19-B Santa Clara River Hydrologic Unit, Lines of Equal Change in Ground Water Elevation, Spring of 19kh to Fall of 1951 19-C Calleguas-Conejo and Malibu Hydrologic Units. Lines of Equal Change in Ground Water Elevation, Spring of 19m to Fall of 1951 20 Fluctuation of Water Levels at Key Wells 21 Relationship Between Water Levels at Key Wells and Ground Water Storage Depletion 22 Mineral Character of Ground Water in Vicinity of Port Hueneme and Point Mugu 23 Elevation of Ground Water and Chloride Ion Concentration 2U-A Ventura Hydrologic Unit, Present and Probable Ultimate Land Use 2U-B Santa Clara River Hydrologic Unit, Present and Probable Ultimate Land Use 2U-C Calleguas-Conejo and Malibu Hydrologic Units, Present and Probable Ultimate Land Use xvi PLATES Plate No , (Continued) 25> Potential Local Water Storage Developments and Conveyance Units for Importation of Water to Ventura County 26 Casitas Dam on Coyote Creek 27 Ferndale Dam on Santa Paula Creek 28 Cold Spring Dam on Sespe Creek 29 Topatopa Dam on Sespe Creek 30 Hammel Dam on Sespe Creek 31 Upper Blue Point Dam on Piru Creek 32 Blue Point Dam on Piru Creek 33 Devil Canyon Dam on Piru Creek 3>k Santa Felicia Dam on Piru Creek 35 Relationship Between Storage Capacity of Reservoirs and Capital Cost 36 Relationship between Storage Capacity of Reservoirs and Net Safe Seasonal Yield 37 Relationship Between Net Safe Seasonal Yield of Reservoirs and Annual Unit Cost 38 Probable Time Required to Fill Reservoirs after Construction 39 Feather River Project UO Profile of Possible Ventura County Diversion-Feather River Project ill Profile of Proposed Ventura County Aqueduct to Connect with System of Metropolitan Water District of Southern California 1*2 Proposed Conveyance and Distribution Systems Plates listed below follow Appendix B in Volume II B-1A, IB, 1C Areal Geology B-2 Stratigraphic Columns - Ventura County Region B-3 Submarine Topography and Diagrammatic Sections xvii EARL WARREN GOVERNOR STATE OF CALIFORNIA STATE WATER RESOURCES BOARD PUBLIC WORKS BUILDING SACRAMENTO 5. CALIFORNIA C. A. GRIFFITH, CHAIRMAN. AZUSA B. A. ETCHEVERRV, VICE CHAIRMAN, BERKELEY HOWARD F. COZZENS, SALINAS CLAIR A. HILL, REDDING October 1, 1953 R. V. MEIKLE, TURLOCK ROYAL MILLER, SACRAMENTO PHIL D. SWING, SAN DIEGO A. D. EDMONSTON. STATE ENGINEER SECRETARY ADDRESS ALL COMMUNICATIONS TO THE SECRETARY Honorable Earl Warren, Governor, and Members of the Legislature of the State of California Gentlemen : I have the honor to transmit herewith Bulletin No. 12 of the State Water Resources Board, entitled "Ventura County Investigation", as authorized by Chapter l£lli, Statutes of 19h5>, as amended. The Ventura County Investigation was conducted and Bulletin No. 12 was prepared by the Division of Water Resources of the Depart- ment of Public Works, under the direction of the State Water Resources Board. Funds to meet the cost of the investigation and report were provided as follows: State of California (State Water Resources Board), $30,000; County of Ventura, $30,000. Information and data developed in the current state-wide investigation with state funds were used in con- nection with this investigation. Bulletin No. 12 contains an inventory of the underground and surface water resources of Ventura County, estimates of present and probable ultimate water utilization, estimates of present and probable ultimate supplemental water requirements, preliminary plans and cost estimates for local water development works, and for works for import- ing water from sources outside the County. Very truly yours, ^f r* C. A. Griffith Chairman xviii ACKNOWLEDGMENT Valuable assistance and data used in the investigation were contrib- uted by agencies of the Federal Government, cities, counties, public districts, and by private companies and individuals. This cooperation is gratefully ac- knowledged. Special mention is made of the helpful cooperation of the following: Board of Supervisors, County of Ventura Ventura County Flood Control District Ventura County Water Survey Los Angeles County Flood Control District United Water Conservation District Santa Clara Water Conservation District Metropolitan later District of Southern California California State Division of Highways California State Department of Fish and Game United States Geological Survey United States Soil Conservation Service United States Navy Department Harold Conkling, Consulting Engineer John Mann, Consulting Geologist Southern California Edison Company American Pipe and Construction Company Fruit Growers Laboratory, Inc # xix ORGANIZATION STATE WATER RESOURCES BOARD C. A. Griffith, Chairman, Azusa H. P. Cozzens, Salinas R. V. Meikle, Turlock B. A. Etcheverry, Berkeley Royal Miller, Sacramento Clair A. Hill, Redding Phil D. Swing, San Diego A. D. Edmonston, State Engineer Secretary and Engineer Sam R. Leedom, Administrative Assistant xx ORGANIZATION STATE DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES Frank B. Durkee Director of Public Works A. D. Edmonston State Engineer T. B. Waddell Assistant State Engineer The investigation was conducted and this bulletin was prepared under the direction of W, L. Berry Principal Hydraulic Engineer and Max Bookman Principal Hydraulic Engineer by R. M. Edmonston Senior Hydraulic Engineer and T. M, Stetson Assistant Civil Engineer R. G. Thomas Assistant Engineering Geologist L. A. Mullnix Assistant Hydraulic Engineer P. E. Hood Assistant Civil Engineer A. F. Nicolaus . . . , Assistant Hydraulic Engineer T. A. Sanson Assistant Hydraulic Engineer J. 0. McClurg Junior Civil Engineer xxi Assistance was furnished by Willets ............ Supervising Hydraulic Engineer Page . . . . . Senior Hydraulic Engineer Keysor • . • • Associate Engineer, Design and Construction of Dams Bean . . . . Associate Engineering Geologist James . . . ♦ Associate Engineering Geologist Shannon ••* Associate Soil Technologist Sturm ••*. Associate Economist McKillop Assistant Hydraulic Engineer Powell • Assistant Hydraulic Engineer Terry . Assistant Hydraulic Engineer Banks • Assistant Civil Engineer Cedarholm Assistant Civil Engineer Eason .... Assistant Civil Engineer Haley Assistant Civil Engineer Angelos ... Junior Civil Engineer Blakemore, Jr Junior Civil Engineer Florian . Junior Civil Engineer Harper ... Junior Civil Engineer Terrazas . . ... Junior Civil Engineer McCann . • Junior Engineering Geologist O'Neill • . Junior Engineering Geologist Parent i Senior Delineator James Senior Delineator Plank Delineator Zablodil ........... Delineator Ground water phases of this bulletin were reviewed by a staff committee composed of H. 0. Banks • Assistant State Engineer G. B. Gleason Supervising Hydraulic Engineer E. C. Marliave Supervising Engineering Geologist Henry Holsinger, Principal Attorney T. R. Merryweather, Administrative Officer D. B. J. M. J. W. R. T. L. B. J. W. N. D. D. H. D. 0. W. L. H. R. J. P. D. E. R. N. R. E. J. E. F. S. C. L. F. X. D. L. A. T. J. A. J. L. R. v/. H. P. xxii ORGANIZATION County of Ventura VENTURA COUNTY FLOOD CONTROL DISTRICT Board of Supervisors Robert A. Lefever, Chairman Lester A. Price Edwin L. Carty C. H. Andrews A. C. Ax Robert L. Ryan, Engineer - Manager xxi 11 CHAPTER I. INTRODUCTION In common with many other portions of southern California, Ventura County- has recently experienced an increase in water utilization during a period of severe drought, and as a result is confronted with the necessity of developing additional water supplies to meet its expanding needs. Water resources problems of Ventura County are manifested in perennial lowering of ground water levels, sea-water in- trusion to pumped aquifers, degradation of ground water quality, and general dimi- nution of surface and ground water supplies during periods of drought to quantities inadequate to satisfy requirements. The initial alleviation of these problems will involve further regulation of the erratic local water supply, so that waste con- served during wet periods can be made available for beneficial use during periods of drought. Final solution of water problems of Ventura County will lie in impor- tation of water supplies from outside sources. Authorization for Investigation In consideration of the critical water supply situation in Ventura County, the Board of Supervisors of the Ventura County Flood Control District presented a resolution to the State Water Resources Board, dated October 2U, 19!?0, requesting a comprehensive investigation of the water resources of the County. The State Water Resources Board referred the request to the State Engineer for preliminary examina- tion and report on the need for such an investigation and an estimate of its scope, duration, and cost. The State Water Resources Board on April 6, 1951* approved a recommenda- tion by the State Engineer, based on findings of the preliminary examination, for a two-year cooperative investigation, and authorized negotiation of an agreement with the Ventura County Flood Control District, The agreement, between the State Water Resources Board, the County of Ventura, and the State Department of Public Works acting through the agency of the State Engineer, was executed on April 15, 193>1» It provided that the work 1-1 "shall consist of (1) a complete review of reports of prior investigations concerning the water resources of Ventura County; (2) field investigations and office studies to determine (a) the location, occurrence, and condi- tion of water resources of the County, both surface and underground, (b) present water utilization including its nature, extent, and a survey of water service agencies, (c) ultimate water requirements, (d) preliminary general plans and estimates of cost for development and utilization of local water resources of the County to the maximum practicable extent, (e) required supplemental water supply from outside sources, (f) possible outside sources for required supplemental supply, including preliminary plans for importation and estimates of costs; and (3) the formulation of a report thereon. " This agreement authorized provision of funds to defray costs of the investigation for one year. A supplemental agreement executed by the same parties on May 1, 19^2$ authorized funds to complete the investigation and report. Funds to meet the costs of the investigation and report to the extent of $60,000 were provided on a matching basis, !*330,000 from the County of Ventura and ^30,000 from the State Water Resources Board. Of the funds made available under the agreement, not more than | 10, 000 were to be expended on exploration work and surveys at dam and reservoir sites. Additional funds have been expended in investi- gation of Ventura County by the State Water Resources Board in connection with the current State-Wide Water Resources Investigation, and by the State Division of Water Resources for studies of quality of water pursuant to sections 229 and 230, Divi- sion 1 of the California Water Code, certain results of which have been used in connection with the Ventura County Investigation. Copies of the two agreements between the State Water Resources Board, the County of Ventura, and the Department of Public Works are included in Appendix A. Related Investigations and Reports Review was made of reports of prior investigations dealing with various phases of water resources problems of Ventura County, extending back to and includ- ing Division of Water Resources Bulletin No. U6, "Ventura County Investigation, 1933" • Investigational reports prior to 1933 were not reviewed, as any pertinent data contained therein were evaluated and utilized in the preparation of Bulletin No. U6. 1-2 Pursuant to a request by the Board of Supervisors of the Ventura County- Flood Control District on July 27, 1951, there was submitted to that Board in Novem- ber, 1951, a report entitled "Review of 'Report on Casitas Dam and Reservoir 1 by Board of Consultants, May 1, 1951" • On November 28, 1951, the Board of Supervisors of the Ventura County Flood Control District requested a review of a report, prepared by the staff of the District, on a plan of distributing water from the proposed Casitas Reservoir. In accordance with this request, a report entitled "Review of 'Memorandum on Distribu- tion of Water Stored in Casitas Reservoir and Matilija Reservoir to Lands and Users in the Year 1975, November 1951' " was prepared and submitted to the District on June 30, 1952. In addition, the following listed published and unpublished reports were reviewed during the investigation, and certain information and data presented therein were used in the preparation of this bulletin. "Ventura County Investigation", Bulletin No. 1*6, Division of Water Re- sources, California State Department of Public Works. 1933* "Ventura County Investigation, Basic Data for the Period 1927 to 1932, Inclusive", Bulletin No. I46-A, Division of Water Resources, California State Department of Public Works. "Future Water Supply for Ventura, California", J. B. Lippincott. May, 193iu "Report on Survey of Ventura River, California, for Flood Control", War Department, United States Engineer Office. October 15, 19U0. "Change in Ground Water Elevation in Various Pumping Areas, Ventura County, California, 1928 to 19hl", Richard H. Jamison. Transaction of 19lt2 of the American Geophysical Union. "Survey Flood Control, Calleguas Creek, California", War Department, United States Engineer Office. December 23, 19i;2. "Soil and Water Conservation Research Needs in the Simi Valley and Adja- cent Areas, Ventura County, California", United States Department of Agriculture, Soil Conservation Service, Office of Research. February, 1911. "Report on Survey of Santa Clara River, California, for Flood Control", War Department, United States Engineer Office. December 20, 19li5« 1-3 "Flood Control and Water Conservation, Ventura County Flood Control District, Zone One", Donald R. Warren Company. 1945. "Flood Control and Water Conservation, Ventura County Flood Control District, Zone Two", Donald R. Warren Company. 1945. "Flood Control and Water Conservation, Ventura County Flood Control District, Zone Three", Donald R. Warren Company. 1945. "Flood Control and Water Conservation, Ventura County Flood Control District, Zone Four", Donald R. Warren Company. 1946. "Water Supply of Santa Clara Water Conservation District", Harold Conkling. November 19, 1947. "Water Supply, Newhall Ranch", Harold Conkling. January, 194&. "Safe Yield - Matilija Reservoir", Harold Conkling. May, 1948. "Development of a Supplemental Water Supply for Zone 2, Ventura County Flood Control District", Harold Conkling. September, 1949. "Demand on Casitas Reservoir and Safe Yield", Harold Conkling. April, 1950. "Hydrology of Zone 3, Ventura County Flood Control District", Harold Conkling. June, 1950. "Exportation of Water from Piru Creek to Zone No. 3", Richard H. Jamison. August, 1951. "Water Resources of California", Bulletin No. 1, California State Water Resources Board. 1951. "Overdraft on the Deep Aquifer in Pleasant Valley and Possibilities of Recharge by Spreading", John F. Mann, Jr. July 3, 1952. "Report of Investigation and Recommendations for Acquisition and Con- struction of a Water Conservation System", United Water Conservation District of Ventura County, California. October, 1952. "Ground Water Replenishment by Penetration of Rainfall, Irrigation and Water Spreading in Zone 3, Ventura County Flood Control District, California", United States Department of Agriculture, Soil Conser- vation Service, Research Branch. April, 1953. The Division of Water Resources is presently conducting surveys and studies for the State-Wide Water Resources Investigation, authorized by Chapter 1514, Statutes of 1945, as amended. This investigation, under direction of the State Water Resources Board, has as its objective the formulation of The California Water Plan for full conservation, control, and utilization of the 1-4 State's water resources to meet present and future water needs for all bene- ficial purposes and uses in all parts of the State, insofar as practicable. As a result of this investigation, the State Water Resources Board in May, 1951., ' published "Report on Feasibility of Feather River Project and Sacramento -San Joaquin Delta Diversion Projects Proposed as Features of the California Water Plan" . Included as an integral feature of these projects is a diversion conduit to deliver supplemental water to Ventura County. These projects were authorized and adopted by the 1951 Legislature in Chapter 1441, Statutes of 1951. Under this authorization, provision was made for the construction of works, operation, and maintenance thereof by the Water Project Authority of the State of California. Financing the construction of works was provided for in the authorizing act through the issuance and sale of revenue bonds and through receipt of contribu- tions from other sources. The Division of Water Resources, since 1951, has been continuing investigations, studies, and surveys preparatory to construction of works, through budgetary appropriation by the Legislature. Cooperation With Other Agencies In addition to cooperation extended to the Division of Water Resources in obtaining and utilizing basic data and information as acknowledged herein- before, certain phases of the investigation were conducted under programs of mutual cooperation with other agencies then engaged in analyzing water resources problems in various portions of Ventura County. These cooperative programs re- sulted in prevention of duplication of effort, and permitted a more detailed analysis to be made of the affected areas. An agreement, entitled "Memorandum of Understanding with Reference to Water Resources Investigation of Ventura County", was entered into on April 23, 1951, by the Division of Water Resources, United Water Conservation District, and Ventura County Flood Control District. The objective of this agreement was to co- ordinate the work of the three agencies involved in the investigation of the water 1-5 problems of the Santa Clara River Valley. Copies of the memorandum of understand- ing, and supplements thereto entered into by the same agencies on October 1, 1952, and November, 19!?2, aro included in Appendix A. In order to provide certain necessary basic data relating to dam and res- ervoir sites on tributaries of the Santa Clara River, prior to commencement of field work by the Division of Water Resources on July 1, 1951, a service agreement was entered into between the Ventura County Flood Control District and the Division of Water Resources on April 2h, 1951, wherein the District was to procure and provide the Division with these data and be reimbursed therefor by the Division in an amount not to exceed $1,500. The terms of this agreement were executed, and the District was subsequently reimbursed in the amount of 1,500. During the course of the investigation, a cooperative hydrographic pro- gram was carried on by the Ventura County Water Survey, United Water Conservation District, Santa Clara Water Conservation District, United States Geological Survey, and Division of Water Resources, This program included measurements of flood flow and rising water at selected points on various watercourses throughout the County, together with maintenance of stream gaging stations. The United States Department of Agriculture, Soil Conservation Service, Research Branch, under terms of a cooperative agreement with the Ventura County Flood Control District, entered into on November 1, 1950, conducted a study of ground water replenishment by penetration of rainfall, irrigation, and water spread- ing in Ventura County Flood Control District, Zone 3. The Division of Water Re- sources extended cooperation to the Soil Conservation Service by supplying basic hydrologic data and results of a geological investigation of the area under consid- eration, including the location and extent of ground water aquifers and of substrata which might impede or prevent the downward movement of waters spread on the ground surface. The results of the Soil Conservation Service study are contained in a re- port entitled "Ground Water Replenishment by Penetration of Rainfall, Irrigation, 1-6 and Water Spreading in Zone 3, Ventura County Flood Control District, California, April, 1953". Certain data contained in this report were utilized in the Ventura County Investigation, Scope of Investigation and Report It has been stated that under provisions of the authorizing agreements the general objectives of the Ventura County Investigation included analysis of the quality, replenishment, and utilization of the underground water supplies of the County, and the preparation of preliminary general plans and estimates of cost for development and utilization of local water resources of the County to the maximum practicable extent. Achievement of these objectives necessitated a comprehensive investigation, the scope of which included full consideration of surface as well as ground water supplies, and the evaluation of present and probable ultimate water utilization and supplemental water requirements. Field work in the investigational area and office studies, as authorized by the initial and supplemental cooperative agreements, commenced on July 1, 195>1, and continued into 1953* In the course of the field investigation, available precipitation and stream flow records were collected and compiled for the purpose of evaluating water supplies of the County. Four stream gaging stations equipped with automatic x were utilized to determine the effects of draft on and replenishment of the ground water basins. Supplemental measurements were made by the Division of Water Resources at wells in certain critical areas in the fall of 1951 and in the spring of 195>2. A continuous record of ground water level fluctuations in the Santa Clara River Valley and in the Oxnard Plain-Pleasant Valley area was available from about 2£ water stage recorders, maintained for many years by the Santa Clara Water Conservation District, The Division of Water Re- sources supplemented these records by maintaining water stage recorders, for vary- ing periods of time, at 27 nonoperating water wells in selected areas. The nature and extent of present land use was determined from a survey conducted in the developed areas of Ventura County during 19h9 and 19£0 in connec- tion with the aforementioned State-Wide Water Resources Investigation. A field check of the results of this survey was made in 19 £l as a part of the Ventura County Investigation. The results of the land use surveys were used in conjunction with water use data to determine present water requirements. As an aid in estimating future water requirements, a land classification 1-8 survey was conducted in 1952, wherein all lands not then urbanized were classified with regard to their suitability for irrigated agriculture. In addition, lands not considered susceptible to irrigation were surveyed in the field to ascertain their potential for urban and suburban developments. Current irrigation practices in the County were studied in order to deter- mine unit application of water to important crops on lands of various soil types, and the influence of climatic factors thereon. Water use data collected from mu- tual water companies and certain large ranches included records of pump discharge, acreages served, crops irrigated, and amounts of water applied. Estimates of total ground water extractions from confined aquifers of the Santa Clara River coastal plain and adjacent areas were made for each of the seasons from l9J4i-U3> through 1951-^2. These estimates were based upon records of power consumption and pump test results supplied by the Southern California Edison Company. Studies were made of the mineral quality of surface and ground waters, in order to evaluate their suitability for beneficial use and to determine the cause of any degradation thereof. In this connection, 1,080 partial and £U2 complete mineral analyses were made of ground waters, and l£6 partial and 23i| complete anal- yses were made of surface waters. In addition, in excess of 600 complete analyses of surface and ground water supplies, dating back to 1927, obtained from Fruit Growers Laboratory Inc., Santa Clara Water Conservation District, Ventura County Farm Advisor, and Division of Water Resources Bulletin No. 1|6, x^ere studied. A de- tailed report on the quality of surface and ground water supplies of Ventura County is scheduled for publication by the Division of Water Resources in the latter part of 1953. Detailed hydrologic studies were made for each of the principal stream systems of the County. These studies included determination of present developed safe yield of surface and ground water supplies, present and probable future sup- plemental water requirements, present waste to the ocean of surface and ground 1-9 waters, and of the portion of this waste susceptible to conservation both by- surface and underground reservoirs. The development of possible plans for additional conservation of local water supplies included field examination of feasible dam sites, together with a geologic investigation thereof. Preliminary designs and estimates of cost were prepared for several heights of dam at many of the sites, and of conveyance and distribution systems, and appurtenant works. Preliminary plans and estimates of cost were also prepared of works for furnishing supplemental water from the proposed Southern California Diver- sion Conduit of the Feather River Project and from the Colorado River supply of the Metropolitan Water District of Southern California. Consideration was given to the financial and organizational aspects attendant on the development of local and imported water supplies. Results of the Ventura County Investigation are presented in this re- port in the four ensuing chapters. Chapter II, "Water Supply", contains evalua- tions of precipitation, surface and subsurface inflow and outflow, and imports of water. It also includes results of investigation and study of underground hydrology, and sets forth estimates of present developed safe yield of surface and ground water supplies. Data regarding the mineral quality of surface and ground water supplies are presented therein. Chapter III, "Water Utilization and Requirements", includes data and estimates of present and probable ultimate land use and water requirements, and contains estimates of present and probable ultimate supplemental water requirements. It also includes available data on demands for water with respect to rates, times, and places of delivery. Chapter IV, "Plans for Water Supply Development", describes preliminary plans for con- servation and utilization of local water supplies, including operation and yield studies, design considerations and criteria, and estimates of cost for the con- struction of works. Similar consideration is given to the development of im- ported water supplies. Chapter V, "Summary of Conclusions, and Recommendations", 1-10 includes a brief summary of conclusions drawn from the first four chapters and recommendations resulting therefrom. Area Under Investigation The area under investigation comprises all lands within the boundaries of Ventura County, with the exception of Anacapa and San Nicolas Islands. Ensu- ing discussions of the County refer to the mainland area only. In addition, proper analysis of the available water supply necessitated investigation of that portion of the drainage area of the Santa Clara River lying within Los Angeles County. Ventura County is situated in the South Coastal Area of California, and adjoins Santa Barbara County on the west, Los Angeles County on the east and south, and Kern County on the north. It is bounded on the southwest by the Paci- fic Ocean, with its coastal frontage extending northwesterly about 40 miles from the Los Angeles county line to Santa Barbara County. Ventura County has an average north and south dimension of about 50 miles, and an average width in an east and west direction of about 40 miles. The mainland portion has an area of 1,857 square miles. The location of the County is shown on Plate 1, "Location of Ventura County" . Drainage Basins Ventura County is characterized by rugged mountainous terrain covering the northerly portion of its area, with most present developments concentrated in the alluvial valleys and lower rolling topography found in the southerly portion. The mountainous area is comprised of the Santa Ynez, Topatopa,, and Piru Moun- tains, which are segments of the Transverse Range of the coastal ranges of California, as are the Santa Monica Mountains found in the southeasterly portion of the County. Numerous ridges in the foregoing mountains extend to elevations in excess of 6,000 feet, attaining a maximum elevation of 8,826 feet at Mt. Pinos at the northerly county boundary. The County is drained by four principal stream systems, namely Ventura 1-11 River, Santa Clara River, Calleguas Creek, and Cuyama River, With exception of the Cuyama River, these streams discharge into the ocean along the coastal front form- ing the southwesterly county boundary. Minor areas in the westerly, northerly, and southeasterly portions of the County drain into Santa Earbara, Kern, and Los Angeles Counties, respectively. Furthermore, in several instances, small areas of the fore- going counties are drained by streams which are otherwise entirely within Ventura County. The headwaters of the Cuyama River rise in the northwesterly portion of the County and thence drain north and west to discharge into the ocean through the Santa Maria River. In addition to the foregoing principal streams, there are many minor watercourses and drainage systems, the largest being i.Ialibu Creek, which drains the southerly portion of the County. The drainage area of the Ventura River comprises 226 square miles, of which 19 h square miles are designated mountains and foothills, and 32 square miles valley and mesa lands. Elevations in the drainage area vary from a maximum of 6,003 feet above sea level at Monte Arido in the northwesterly extremity of the watershed, | to sea level at the mouth of the river. The mean seasonal natural runoff of the Ventura River at its mouth has been estimated to be about 67,800 acre-feet. Pres- ent developments are concentrated in the small alluvial valleys and adjacent hills south and east of the confluence of Matilija and North Fork Matilija Creeks, which are the principal tributaries of the Ventura River. The Santa Clara River drains an area above its mouth of l,6o£ square miles, of which 1,U55 square miles are designated mountains and foothills, and lf>0 square miles valley and mesa lands. The river flows generally in a southwesterly direction from its headwaters in Los Angeles County, at elevations in excess of 5,000 feet, to the Pacific Ocean near Oxnard. Its principal tributaries are Sespe Creek with a drainage area of about 2%k square miles above the gage near Fillmore, and Piru Creek with a drainage area of about it32 miles above the gage near Piru, both of which flow easterly and then southerly to join the main stream near the 1-12 towns of Fillmore and Piru, respectively. Another important tributary, Santa Paula Creek, drains an area of I4O square miles southwesterly of the Sespe Creek watershed and, flowing generally south, has its confluence with the Santa Clara River at the town of Santa Paula, Urban and agricultural developments are found along the Santa Clara River bottomlands and on the broad coastal plain at its mouth. The drainage areas of Sespe, Piru, and Santa Paula Creeks are comprised primarily of national forest lands, wherein few developments prevail. The mean seasonal natural runoff of the Santa Clara River at its mouth is estimated to be about 2l6,l|00 acre-feet. The headwaters of Calleguas Creek and its principal tributary, Conejo Creek, originate in the Santa Susana and Santa Monica Mountains at elevations in excess of 3»000 feet. The drainage area, poorly defined in the lower reaches of the stream, comprises about 331 square miles. Oak Ridge, a relatively narrow elon- gated range of hills extending in. a east-west direction, separates the Calleguas Creek watershed from that of the Santa Clara River on the north. The watershed is defined by the Santa Susana Mountains on the east and by the Santa Monica Mountains on the south. The system drains generally in a southwesterly direction, and dis- charges into the ocean through Mugu Lagoon about seven and one-half miles south- easterly of Port Hueneme. The drainage area is characterized by a more moderate relief than that of the Ventura and Santa Clara River watersheds, with most of the area lying below 1,000 feet in elevation. Present urban and agricultural develop- ments occur in the relatively small alluvial valleys and adjacent hills throughout the area, and on the coastal plain across which Calleguas Creek flows in its lower- most reaches. The mean seasonal natural runoff of Calleguas Creek is estimated to be about 1^,200 acre- feet. The southerly slopes of the Santa Monica Mountains within Ventura County are drained by Las Virgenes and Triunfo Creeks, tributaries of Malibu Creek, to- gether with several minor streams discharging directly into the ocean. Runoff from 1-13 these streams is small and developments within their drainage areas are of a minor nature. Climate The Mediterranean type of climate typical of the South Coastal Area pre- vails in Ventura County, with proximity to the ocean providing a moderating effect on climatic conditions throughout the developed area. A long, dry, warm summer season is followed by a shorter wet winter period accompanied by cooler tempera- tures. In excess of 80 per cent of the mean seasonal precipitation occurs during the months of December through March. Precipitation occurs generally in the form of rainfall, except in the mountainous regions where there is some snowfall in most years. Fog is prevalent along the coast during portions of each year. Temperature extremes generally increase with elevation and distance from the coast. The grow- ing season, or lapse of time between killing frosts, is long, and generally de- creases with elevation and distance from the coast. Since killing frosts on the coastal plain of the Santa Clara River Valley are extremely rare, portions of this area are producing as many as three crops per year. Certain pertinent climatological data for three selected stations in Ventura County are shown in the following tabulation: Station Elevation, in feet Recorded temperature , in degrees F, Max- : Min- : Av- imum : imum : erage Mean seasonal precipitation, in inches of depth Average number of days between killing frosts Ojai Oxnard Santa Paula 750 51 275 119 99 105 13 29 27 61 S9 lb. 76 Ik. hi 17.50 232 332 277 Geology Ventura County lies within the Transverse Ranges Ge amorphic Province of California. Formations present include igneous and metamorphic rocks of pre-Cre- taceous age, marine and continental sediments of Cretaceous to Recent age, and l-lli volcanic rocks of Tertiary age. With exception of the Recent stream deposits, all formations are to some extent deformed. In general, the structures, including fold axes and faults, trend in an east-west direction. Ground water occurs to some extent in all of the foregoing formations. The principal aquifers are composed of continental and marine sediments of Recent and Pleistocene age. In certain areas, wells are supplied from fractured volcanic rocks of the Tertiary system, or from fissures in c rystalline or consolidated rocks of pre-Quaternary age. The fractured rocks generally yield little water. However, in some localities this source constitutes the entire water supply. A detailed geologic report is included as Appendix B. Soils Soils of Ventura County vary markedly as to type, composition, depth, and other physical and chemical properties, in accordance with origin of the parent ma- terial, nature of deposition, and age and degree of development since the time of deposition. In general, the soils can be divided into three broad groups: (l) residual soils, which have been developed in place from the disintegration and wea- thering of consolidated rocks, both of sedimentary and basic igneous origin; (2) old valley filling and coastal plain soils, which are derived from elevated, uncon- solidated water-laid deposits which have undergone marked changes since their de- position} and (3) recent alluvial soils, which are derived from sediments that have undergone little or no change or internal modification since their deposition, ■ These soils have their origin in a variety of materials, including shale, sandstone, conglomerate, basic igneous rocks, and old valley filling deposits. Residual soils are identified with hill and mountainous areas. Soil tex- tures vary from medium to heavy; and soil depth, although variable, is generally shallow, containing inclusions of rock outcrop throughout most of the areal extent of the group. Drainage is generally good, Moisture retention is adequate except where the underlying bedrock is near the surface. Residual soils comprise a 1-1* relatively small area, occupying the rolling hills and ridges at the perimeter of the interior valleys. Soils of the old valley filling and coastal plain groups have a varied topography, occurring both on hill and rolling lands and on smooth and eroded marine or stream terrao*.,?. They also occur on sloping remnants of old alluvial fans that have either bee.i elevated sines time of deposition, or have been left in their pres- ent position through the cutting of deeper stream channels or valleys through them. The soils are usually intermediate in elevation between the residual and recent alluvial groups. They have medium texture with friable surface composition, and are well suited to irrigated agriculture. Subsoils are somewhat more compact and heavier in texture, with local tendencies toward hardpan. Surface drainage is gen- erally good, but subsurface drainage is in some cases retarded by the heavy compact nature of the subsoil. No indication of the accumulation of harmful salts in the soil solution has been noted as a result of this condition. In portions of the County, particularly along the northern and eastern sides of Ojai Valley, this group contains considerable rock outcropping. Topography identified with the recent alluvial soils is smooth and gently sloping. This group covers nearly the entire coastal plain of the Santa Clara River Valley, and also occurs as river and creek bottom deposits along the Santa Clara River and its tributaries. These soils comprise the numerous alluvial fans found at the mouths of tributary creeks throughout the County. Depth of soil is generally good, with textures grading from light to very heavy. The soils of the group have the common characteristic of stratification in the subsoil. On all allu- vial fans, both surface and internal drainage is good. However, in some of the lower valleys where the soils are quite heavy, drainage is poor, as in the southerlj portion of the coastal plain and extending northerly therefrom toward Camarillo, An extensive drainage system has been constructed in this area to alleviate this prob- lem. In portions of the coastal plain, where drainage works have not been con- structed, there are heavy concentrations of soluble salts in the soil solution. 1.16 ■, Recent alluvial soils comprise the largest area in the County presently developed to either irrigated agriculture or developments of an urban nature. Present Development The establishment of Mission San Buenaventura in 1782 by Franciscan Father Junipero Serra marked the beginning of the development of Ventura County. After California became a state in 185>0, and until legislative action in 1872, the area now included within Ventura County was part of Santa Barbara County. Early-day activities were of an agricultural nature and devoted to the sustenance of the mission settlement. Hater supplies for the mission were obtained by diversion from the Ventura River. Portions of the original aqueduct and receiv- ing reservoir, used for domestic and minor irrigation purposes, are still intact. In common with other portions of Spanish California, Ventura County, in the early 19th century, was divided into several large land grants, known as ranchos. The principal activity of the "rancheros" was the raising of cattle, sheep, horses, and mules on extensive pasture lands. After the acquisition of California by the United States and the accompanying decline of the ranchos, extensive plantings were made of wheat, barley, corn, and other dry-farmed crops. During the decade from 1880 to 1890, the economy of Ventura County exper- ienced a marked change with the introduction of large-scale irrigation in areas where water supplies were readily available. The original plantings of citrus and walnuts were made about this time in Ojai Valley and along the Santa Clara River. These crops, particularly the former, have continued to have great commercial im- portance to the present day. Beans were introduced to the Oxnard Plain just prior to the turn of the century. The subsequent rapid expansion of this crop has re- sulted in the designation of the Oxnard Plain as the "bean basket of the world". Originally, irrigation was accomplished through diversion of surface wa- ters. However, increased water utilization, coupled with protracted periods of drought wherein flow in Ventura County streams diminished to negligible proportions 1-17 during the summer and fall, caused irrigators to turn to utilization of supplies available in underlying ground water basins. At first centrifugal pumps were em- ployed, but later declining water levels necessitated the installation of deep-well turbine pumps throughout most of the irrigated areas. At the present time the Santa Clara River Valley, the coastal plain, and portions of the Ventura River and Calleguas Creek drainage areas are extensively developed to irrigated agriculture. However, irrigation developments in many parts of the County have been impeded through lack of firm water supplies. Land use sur- veys conducted in Ventura County during 191*9-50 indicated that there were, at that time, in excess of 109,000 net acres of irrigated land. Leading crops were citrus with about h3t 000 acres, beans with about 33,000 acres, and walnuts with slightly less than 18,000 acres. The value of crops produced in Ventura County in 195>0 was in excess of $£0,000,000, as compared to a reported value of about $20,000,000 in 19U0. At the present time and for many years past, the oil industry has been a leading producer of revenue. Large areas are presently devoted to oil fields and appurtenant developments. Numerous active oil seeps in various portions of the County attracted oil prospectors as early as the middle of the 19th century. Other principal industries in Ventura County, excluding those allied with the production of oil, are citrus packing and vegetable processing. The American Crystal Sugar Company's sugar beet processing plant in Oxnard is the largest of the latter. Sand and gravel works supply local demands for aggregates. Concrete pipe, used in irrigation distribution and drainage systems, is manufactured locally. The United States Navy maintains a large advanced base depot at Port Hueneme, as well as an air missile test center at Point Mugu, A United States Air Force base is lo- cated near Camarillo, Electrical energy is brought into the County by the Southern California Edison Company, The 1950 Federal census reported the population of Ventura County to be 11U,6U7, From 19U0 to 1950, the population increased by hh, 962, or by about 65 pel 1-18 cent of the reported 1940 total of 69,685. The City of Oxnard, which in 1940 ranked third in population of incorporated cities in the County, was first in 1950 with a population of 21,567. The population of other incorporated cities in 1950, in order of their magnitude, was: Ventura, 16,534; Santa Paula, 11,049; Fillmore, 3,884; Port Hueneme, 3,024; and Ojai, 2,519. Ventura County is well served with rail, air, and highway transporta- tion facilities. The coast route of the Southern Pacific Railroad passes through the County, as do U. S. Highways 101 and 399 and several state highways. Local products are exported by sea from Port Hueneme. In addition, offshore loading of oil tankers is effected by means of submarine pipe lines constructed from the oil fields in the vicinity of the City of Ventura. Recreational facilities are available in county parks, beaches, and in the Los Padres National Forest. Ojai Valley is a noted southern California resort area. The assessed valuation of Ventura County in the fiscal year 1952-53, as reported by the County Auditor, was $283,230,490. Ventura County is among the top quarter of counties in California from the standpoint of assessed valuation. Water service is provided through individual effort, by municipal and other public agencies, and by many private agencies. In addition, many public districts have been formed to deal with the problems of water supply, flood con- trol, drainage, and land reclamation. The activities of these districts, their powers, and purposes are described in Appendix D. The boundaries of the Ventura County Flood Control District, the Santa Clara Water Conservation District, the United Water Conservation District, the Ventura Municipal Water District, and the Simi Valley Water Conservation District are delineated on Plate 2, entitled "Major Water Districts, 1953". Hydrologic Units In order to facilitate analysis of present and probable future water 1-19 supply problems of Ventura County, the southerly portion thereof has been divided into four hydrologic units. These units, the boundaries of which are shown on Plate 3, "Hydrologic Units", have been designated "Ventura", "Santa Clara River", "Calle- guas-Conejo", and "Malibu". Boundaries of the hydrologic units were defined after giving consideration to those factors of water supply and utilization, topography, and geology, which affect hydrologic analysis, and in order to include those lands having correlative water problems. In general, each unit extends to definite political or topographic boundaries. It will be noted on Plate 3 that the northerly limits of the Ventura and Santa Clara River Units conform generally to the boundary of the Los Padres National Forest, except in those instances where contiguous bodies of irrigable land encroach onto the federal reservation. The complex nature of the Ventura, Santa Clara River, and Calleguas-Conejo Units necessitated further division thereof into subunits, the boundaries of which are also shown on Plate 3« Table 1 presents the total area of each of the hydrologic units and subunits. 1-20 TABLE 1 ARFAS OF HYDROLOGIC UNITS AND SUBMITS Name • • : Acres Ventura Upper Ojai 9,670 Ojai 10,800 Upper Ventura River 25,990 Lower Ventura River 31,170 Rincon 15,390 Subtotal 93,020 Santa Clara River Eastern 2,800 Piru 1*7,310 Fillmore US $ hS0 Santa Paula 52,01*0 Mound 1?,U90 Oxriard Forebay 6,170 Oxnard Plain 16,^60 Pleasant Valley- 36,010 Subtotal 253,730 Calleguas-Conejo Simi 50,010 East Las Posas 52,U80 West Las Posas lii,l60 Cone 30 28,930 Tierra Rejada U,390 Santa Rosa 8,030 Subtotal 158,000 Malibu 52,670 TOTAL 557,i;20 There are certain other relatively small areas of Ventura County which, although largely undeveloped, are by virtue of their soils and topography suscepti- ble to future irrigation development. These areas are located primarily in the northerly portion, in the upper reaches of Piru Creek and the Cuyama River. In addition, certain lands included within the Los Padres National Forest, other than those included within the aforementioned hydrologic units, either presently use small amounts of water or are considered to have a small potential water require- ment • 1-21 CHAPTER II. WATER SUPPLY The principal sources of water supply of Ventura County are direct precipitation and runoff from tributary drainage areas. A small import of Santa Clara River water from Los Angeles County, together with relatively minor quantities of water released from the Los Angeles Aqueduct in the upper reaches of the Santa Clara River watershed have contributed to the supply. So far as was determined during the investi- gation, there is no record of export of water from Ventura County. The water supply of the County is considered and evaluated in this chapter under the general headings: "Precipitation", "Runoff", "Underground Hydrology", "Quality of Water", and "Safe Yield of Presently Developed Water Supply". The following terms are used as defined in connection with the discussion of water supply in this report: Annual - This refers to the 12-month period from January 1st of a given year through December 31st of the same year, sometimes termed the "calendar year". Seasonal - This refers to any 12-month period other than the calendar year. Precipitation Season - The 12-month period from July 1st of a given year through June 30th of the following year. Runoff Season - The 12-month period from October 1st of a given year through September 30th of the following year. Investigational Seasons - The two runoff seasons of 1951-52 and 1952-53? during which most of the field work of the Ventura County Investigation was performed. 2-1 Mean Period - A period chosen to represent conditions of water supply and climate over a long series of years. Base Period - A period chosen for detailed hydrologic analysis because prevailing conditions of water supply and climate were approximately equivalent to mean conditions, and because adequate data for such hydrologic analysis were available. Mean - This is used in reference to arithmetical averages relating to mean periods. Average - This is used in reference to arithmetical averages relating to periods other than mean periods. In studies for the current State-Wide Water Resources Investi- gation, it was determined that the 50 years from 1897-98 to 1946-47, inclusive, constituted the most satisfactory period for estimating mean seasonal precipitation generally throughout California. Similarly, the 53-year period from 1894-95 to 1946-47 > inclusive, was selected for determining mean seasonal runoff. In studies for the Ventura County Investigation, conditions during these periods were considered repre- sentative of mean conditions of water supply and climate. Studies were made to select a base period for hydrologic analysis of Ventura County during which conditions of water supply and climate would approximate mean conditions, and for which adequate data on water supply, water utilization, and ground water conditions would be available. It was determined that the 15-year period from 1936-37 through 1950-51 was the most satisfactory in this respect. The average seasonal water supply during this chosen base period so closely ap- proached that of the mean period throughout the County that its magni- 2-2 tude was considered to be equivalent to that of the mean period. Furthermore, the base period exemplifies the historic cyclic nature of the water supply of Ventura County. It includes a series of eight years from 1936-37 through 1943-44 wherein the average seasonal water supply substantially exceeded that of the mean period, followed by a series of seven years wherein the average seasonal water supply was considerably less than that of the mean period. Accordingly, these periods are hereinafter referred to as the "wet period" and "drought period", respectively. Water resources problems of Ventura County stem in part from the erratic and apparently cyclic occurrence of its water supply. The relationship between water supply and utilization during drought periods establishes the magnitude of these problems. Since 1894 there have been three major drought periods, namely: 1894-95 through 1903-04; 1922- 23 through 1935-36; and 1944-45 through 1950-51. Water supply data are almost entirely estimated for the earliest of these periods, and par- tially so for the period from 1922-23 through 1935-36. Fairly reliable data are available throughout the County for the drought period in- cluded in the chosen base period. Although for study purposes, this latter period has been adopted as representative of drought conditions in Ventura County, it has been concluded that in some portions of the County, the period from 1922-23 through 1935-36 was of somewhat greater severity in regard to accumulated deficiency in water supply. The results of certain studies presented later in this bulletin should be qualified accordingly. 2-3 Precipitation Ventura County receives a substantial portion of its preci- pitation from storms originating in both the West and Northwest Pacific and in the Southwest Pacific, almost entirely during winter months. Precipitation, comprising the largest item of the County's water supply, is consumed or disposed of in various ways: evaporation from plant and ground surfaces soon after the occurrence of rain; through accre- tion to the depleted soil moisture of the soil mantle, which source subsequently furnishes water to meet consumptive requirements of vegetal cover; through deep percolation to ground water in absorptive areas; and through surface runoff. Precipitation Stations and Records During the investigational seasons there were 57 precipita- tion stations in operation in Ventura County. Five of these stations were equipped with continuous recorders, and the remainder with non- recording type gages which were usually read daily. In addition, there have been some 50 precipitation stations in operation in Ventura County for varying lengths of time, which are now inactive. The longest record is that of the station at Ventura, which extends back to 1873. The stations are numerous and well distributed over the southerly portion of the County, but in the northerly and less accessible mountainous regions few stations have been established and the precipitation pattern therein is less susceptible to reliable determination. Locations of the precipitation stations within and adjacent to Ventura County are shown on Plate U, "Lines of Equal Mean Seasonal 2-4 precipitation". Map reference numbers correspond to those presented in State Water Resources Board Bulletin No. 1, "Water Resources of California". For those stations not appearing in Bulletin No. 1, num- bers were assigned consecutively after the last number presented in that bulletin. Thirty-nine active precipitation stations in Ventura County having unbroken records of 15 years or longer as of 1950-51 are listed in Table 2, together with the map reference number, elevation, period and source of record, mean, maximum, and minimum seasonal depth of precipitation for each. 2-5 CM 9 CO Q d c •H o TJ ■g 3 £ O m c H o Q CO C cd .,— o a> (0 to cd d) (0 •> rt o «H Ti c -h O <1) G o o U o 2 0) o C co «H O T* -O *h o o •H o Fh U Ph •» c o P •H ID P 0) .5 C o •H ■P cd •P CO P-. fH o ;g<2 1 > kS •H •H CO U h ^> 0-, Ol, -4- CM O »^S I I enn o m l/N. en o -4 en cm en w\ CM^ en m ON ON H H O 3 a> to 1 cd H en I -4 a> p •H CM CM CM iPv I I CM CTN ON On O en On CM cm ir\ l I to H CM ITN On On O en (0 s: u O Q) C p eg sl, X) g a> 1 x o en I -3- >TN CM en te> I I en u> o ON H H to O I I O Cn- -4 -d- On On ir\ cm CM vfN, Ah cm ir\ On On H H o 81 NO H CM en to o en no en 3 to 3 5 O On o O IfN CM ITS R H to -4- O -* to CM to en • • • • • • • • en IT\ l> -4- -4 C- en in H H H H <-* H CM H 0) a) a> a> p p p p aJ cd m cd > > > > •H •H •H •H U h h h £ a. cu a. 3£ I I en H O On O NO rt o X! b0 c t) u cd j^ CD cd 3 h3 (0 K cd cd O 73 P •1-3 cd •H a> c to c: cd cd o o O o IA nO I -4 2-6 Eh < a o M Eh •«: Eh M >H Oh Eh M 3 O 5 w o 3 O Oh -d gi CD 3 Eh 3 o a G •H CO c3 P H e CO 3 o M C\! 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M <0 CM 4 3 3 en § o $-. a> •p I a Eh CD i w CD p CO ■d a> p o o 8 n °8 J* O «5 bflp CO | rt to ■P fl> CO > 3 ctJ ll a h • o • o o o CO O M < m O u ■a Precipitation Characteristics Precipitation in Ventura County occurs primarily as rainfall, although light snowfall is not uncommon in the higher mountainous areas in the northerly portion of the County. Depth of precipitation generally increases from west to east in the southerly developed areas of the County, but decreases in this direction toward the north. Mean seasonal depth of precipitation varies from a maximum of about 32 inches in the Topatopa Mountains to a minimum of about 12 inches in the vicinity of Point Mugu. Storms moving in from the West and Northwest Pacific are first intercepted by the mountains defining the watersheds of Ventura River, Santa Paula Creek, and Sespe Creek; and it is in the higher ele- vations of these watersheds that depth of precipitation is the greatest in the County. The Piru Creek watershed and that of the Santa Clara River above the Los Angeles County line receive less precipitation, since many of the more productive storms have been dissipated prior to reaching these areas. The light mean seasonal depth of precipitation in the Calleguas Creek drainage area, varying from about 12 to 18 inches, results from the relatively low elevation of the watershed and its position beyond the path of the principal storms. Plate 4 depicts the variation in mean seasonal depth of precipitation over the County and in tributary watersheds. In certain instances, the preparation of Plate 4 required extension of incomplete or broken records through correlation with stations having long-term records. Table 3 presents recorded and estimated seasonal depth of precipitation at five selected stations in various portions of the 2-11 County, together with the "precipitation index" for each of the seasons shown. 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Seasonal depth of preci- pitation at Ojai has varied from a minimum of 37 per cent of the mean in 1893-94, when 6.96 inches were recorded, to a maximum of 224 per cent of the mean in 1940-41, when 42.10 inches were recorded. Similar extremes occurred at other long-term stations throughout the County. The erratic seasonal occurrence of precipitation in Ventura County is depicted graphically on Plate 5, entitled "Recorded Seasonal Preci- pitation at Ojai, 1891-92 through 1951-52". The apparent cyclic nature of the occurrence of precipitation at this station is shown on Plate 6, entitled "Accumulated Departure from Mean Seasonal Preci- pitation at Ojai, 1891-92 through 1951-52". About 80 per cent of the seasonal precipitation in Ventura County occurs during the four-month period from December through March It is not unusual, however, for one or more of these months to be extremely dry in a given season. The mean monthly distribution of precipitation at Santa Paula, which may be considered generally representative of the County in this respect, is presented in Table 4« 2-18 TABLE 4 MEAN MONTHLY DISTRIBUTION OF PRECIPITATION AT SANTA PAULA Month Precipitation In inches: In per cent of: of depth : seasonal total: Month Precipitation In inches: In per cent of depth : of seasonal : total July- 0.01 0.1 January- 3.86 22.0 August 0.03 0.2 February 4.07 23.2 September 0.31 1.8 March 3.04 17.4 October 0.62 3.5 April 0.98 5.6 November 1.23 7.0 May 0.38 2.2 December 2.94 16.8 June 0.03 0.2 TOTALS 17.50 100.0 Quantity of Precipitation In certain of the absorptive areas of Ventura County, where- in precipitation constitutes a direct source of ground water replenish- ment, it was necessary to evaluate the total quantity of precipitation for the purpose of required hydrologic analysis. These absorptive areas included the Piru, Fillmore, Santa Paula, and Oxnard Forebay ground water basins, of the Santa Clara River Unit, and the Simi Basin of the Calleguas-Conejo Unit. The mean seasonal quantity of precipitation on these areas was estimated by plotting recorded or estimated mean seasonal depth of precipitation at stations in or near the basins on a suitable base map. Lines of equal mean seasonal precipitation, or isohyets, were then drawn, as shown on Plate 4. 2-19 By planimetering the areas between these isohyets, the weighted mean seasonal depth and total quantity of precipitation were estimated. In order to determine seasonal depth and quantity of precipitation during the base period, the estimates for the mean period were adjus- ted on the basis of recorded precipitation at key stations within or near each of the basins. The results of these estimates are listed in the following tabulation: Estimated Estimated : mean seasonal t average seasonal Ground water : precipitation, : precipitation during basin : in acre-feet : : base period in acre-feet Piru 9,400 Fillmore 26,300 Santa Paula 18,800 Oxnard Forebay 8,700 Simi 12,400 9,600 25,800 18,500 8,400 13,300 Runoff The watersheds within and tributary to Ventura County vary markedly in their production of runoff, depending on their areal extent and other physical characteristics, and on the depth of precipitation. Unit runoff is the greatest from the watersheds of the Ventura River, Santa Paula Creek, and Sespe Creek, with lower values from the watersheds of Piru Creek and Santa Clara River above the Ventura County line. Runoff from the Calleguas Creek system is of relatively minor magnitude. Tribu- tary runoff is disposed of through percolation to ground water storage in absorptive stream channels and artificial spreading grounds, evapora- 2-20 tion, consumptive use of native vegetation, diversions to meet requirements of irrigated agriculture and urban entities, and dis- charge to the ocean. Stream Gaging Stations and Records Long-term records of runoff from streams within or tributary to Ventura County are not available. The longest unbroken records of stream flow in the County are for Matilija Creek at Matilija and Santa Paula Creek near Santa Paula, which are continuous from 1927 to the present time. Broken records extending back to 1911 are available for Ventura River near Ventura, Piru Creek near Piru, and for Sespe Creek, where stations have been maintained at three locations. Contin* uous records of runoff during the base period are available for Matilija Creek at Matilija, North Fork of Matilija Creek at Matilija, Coyote Creek near Ventura, Ventura River near Ventura, Santa Clara River near Saugus, Piru Creek near Piru, Sespe Creek near Fillmore, Santa Paula Creek near Santa Paula, Arroyo Simi near Simi, and Arroyo Las Posas near Moorpark. In general, records of runoff from minor streams throughout the County are nonexistent, except for those instan- ces where such records were obtained during the present investigation and the investigation for Division of Water Resources Bulletin No. 46. Locations of stream gaging stations pertinent to the evalua- tion of the water supply of Ventura County, including the five esta- blished in connection with the Ventura County Investigation, are shown on Plate 7 entitled "Stream Gaging and Water Sampling Stations". In general, map reference numbers shown on Plate 7 are those presented in State Water Resources Board Bulletin No, 1, "Water Resources of 2-21 California". However, for stations not reported in Bulletin No. 1, arbitrary numbers have been assigned, prefixed by an appropriate County designation; i.e., V.C., Ventura County or L.A., Los Angeles County. Table 5 presents a list of the stations shown on Plate 7, together with map reference numbers, drainage areas, periods and sources of records. Records for the five stations established and maintained by the Division of Water Resources during the investigational seasons, and for San Antonio Creek near Mouth, Santa Clara River near Montalvo, Arroyo Simi near Simi, and Arroyo Las Posas near Moorpark, established and maintained by the Ventura County Water Survey, are available in the files of the Division of Water Resources. The Los Angeles County Flood Control District publishes the records for Santa Clara River ^ mile west of County line, Santa Clara River above Lang Railroad Station, Placerita Creek at Ridge Route Highway, and Castaic Creek at State Highway 126. The United States Geological Survey pub- lishes the records for all remaining stations listed in Table 5* 2-22 TABLE 5 STREAM GAGING STATIONS IN OR NEAR VENTURA COUNTY Map : reference: Stream number : : Station : Drainage: : :area, in: Period: Source of : square : of : record : miles : record: a- 1 Matilija Creek At Matilija ^ 1927-53 USGS U- 2 North Fork Matilija Creek At Matilija 15.5 1928-32 1933-53 USGS k- 3 Coyote Creek Near Ventura Ui 1927-32 1933-53 USGS fc- u Ventura River Near Ventura 187 1911-lU 1929-53 USGS U- 5 Santa Clara River Near Saugus iilO 1929-53 USGS ii- 6 Piru Creek Near Piru U32 1911-13 1927-53 USGS U- 7 Hopper Creek Near Piru 23 1930-32 1933-36 1937-53 USGS U- 8 Sespe Creek At Brad- field's Camp 208 1915-27 USGS 14- 9 Sespe Creek At Sespe 257 1911-13 1927-3U USGS li-10 Sespe Creek Near Fillmore 25U 193U-53 USGS li-11 Santa Paula Creek Near Santa Paula ko 1912-13 1927-53 USGS ii-12 Santa Clara River Near kontalvo 1,596 1927-32 19U7-53 VCWS ii-iii Malibu Creek At Crater Camp, near Calabasas 103 1931-53 USGS VC- 1 Matilija Creek Above Matilija Reservoir 51 19U8-53 USGS VC- 2 San Antonio Creek Near Mouth 51 19U9-53 VCWS VC- 3 San Antonio Creek Near Ojai 3U 1927-32 1951-52 DWR 2-23 TABLE 5 (Continued) STREAM GAGING STATIONS IN OR NEAR VENTURA COUNTY :Drainage: : Map tarea, in:Period:Source of reference i Stream i : Station : square : of : record number : miles : record: vc- 1* vc- 5 VC- 6 VC- 7 VC- 8 VC- 9 VC-11 LA- 1 LA- 2 Santa Clara River Sespe Creek Tapo Creek Arroyo Simi Arroyo Las Posas Calleguas Creek J mile west of 6^U 19^8-53 LACFCD County line VC-10 Cone jo Creek Calleguas Creek Santa Clara River Placerita Creek LA- 3 Castaic Creek Near Wheeler Springs Near Santa Sus ana Near Simi Near Moorpark Near Camarillo Near Camarillo At Camarillo State Hospital Above Lang Rail- road Station At Ridge Route Highway At State High- way 126 50 191*8-53 USGS 17 1951-53 DWR 75 118 169 70 251 157 203 1933-53 1933-52 1928-31 1951-53 1927-31 1951-53 1951-53 vcws vcws DWR DWR DWR 191*9-53 LACFCD 191*7-53 LACFCD 191*5-53 LACFCD USGS VCWS LACFCD DWR United States Geological Survey Ventura County Water Survey Los Angeles County Flood Control District Division of Water Resources 2-2U Runoff Characteristics Runoff from streams in Ventura County is derived primarily from rainfall, and as a result exhibits similar monthly and seasonal variations. Absence of snowpack in tributary watersheds causes all streams to diminish rapidly in flow at the conclusion of the winter pre- cipitation season, although some summer flow is maintained by springs in the upper reaches of the more productive watersheds. Following a severe storm, discharge in the larger streams has been known to increase in a few hours time from practically no flow to a rate of thousands of cubic feet per second. Seasonal natural runoff in the principal streams of the County has varied from a maximum in excess of 400 per cent of the mean to a minimum of less than five per cent of the mean. Seasonal vagaries in the runoff of Ventura County streams" are represented graphically on Plate 8, entitled "Estimated Seasonal Natural Runoff of Sespe Creek Near Fillmore". The apparent cyclic nature of the occurrence of runoff at this station is shown on Plate 9, entitled "Accumulated Departure from Mean Seasonal Natural Runoff of Sespe Creek near Fillmore". The monthly variation in seasonal runoff is shown in Table 6. 2-2$ TABLE 6 ESTIMATED AVERAGE MONTHLY DISTRIBUTION OF NATURAL RUNOFF OF SESPE CREEK NEAR FILLMORE, 1936-37 THROUGH 1950-51 • * • * Per cent of Month : Runoff, in j seasonal : acre-feet : total October 790 0.8 November 1,830 1.9 December 7,120 7.5 January 9,U80 10.0 February 2u,$10 25.9 March 32,280 3U.1 April 10,930 ii.5 May 3,760 U.o June 1,820 1.9 July 960 1.0 August 6U0 0.7 September 700 0.7 TOTALS 9U,800 100.0 Quantity of Runoff As described previously, long-term records of runoff in Ven- tura County streams are not available. The natural runoff for each season of the mean period was estimated in State Water Resources Board Bulletin No. 1 for Ventura River near Ventura, Piru Creek near Piru, Sespe Creek near Sespe, Santa Paula Creek near Santa Paula, Santa Clara River at County Line, and Malibu Creek at Crater Camp near Calabasas. Table 7 presents the natural runoff of three representative streams in the County for each season of the base period, together with the seasonal "runoff index" for each of the streams. The term "runoff index" refers to the ratio of the amount of runoff during a given season or period to the mean seasonal amount, and is expressed as a percentage. 2-26 TABLE 7 ESTIMATED SEASONAL NATURAL RUNOFF OF SELECTED STREAMS OF VENTURA COUNTY, 1936-37 THROUGH 1950-51 Matilij a Creek : : Piru Creek : Sespe Creek at Matilij a near Piru : near Sespe Season \ Runoff, : Runoff, : • i Runoff, , Runoff : in ! Runoff : in : Runoff: in index : acre- feet: index : acre-feet s index : acre-feet 1936-37 182 51,200 130 69,700 182 171,000 1937-38 288 81,200 2) 4 129,000 255 239,000 1938-39 1*7 13,200 71 38,200 k9 1*6, 200 1939-1*0 31 8,700 36 19,1*00 35 32,500 191*0-1*1 1*1*1* 125,300 1*21 226,000 1*00 376,000 19U1-U2 1*6 13,000 60 32,200 1*5 1*2,200 19U2-U3 212 59,700 190 102,000 182 171,000 191*3-1*1* 133 37,600 233 125,000 152 11*3,000 I9hh-h$ 51 il*,l*oo 61* 3U,1*00 58 5l*,l*oo 19k$-k6 6U 18,100 60 32,300 69 61*,l*oo 191*6-1*7 3k 9,500 53 28,1*00 aa 1*5,300 191*7-1*8 9 2,1*00 12 6,600 9 8,100 191*8-1*9 9 2,600 11 6,000 10 9,100 19k9-$0 13 3,600 111 7,300 18 16,900 1950-51 5 1,300 h 2,1*00 h 3,500 Average for 15- year base . . period, 1936-37 t through 1950-53 . 105 29,500 107 57,300 101 9l*,800 Average for wet period, 1936-37 through 191*3-1*1 1 173 1*8,700 173 92,700 163 152,600 Average for drought period, 19l*l*-l*5 through L 1950-51 26 7,1+00 31 16,800 31 28,800 Mean for 53-year period, l89l*-95 through 191*6-1*7 100 28,200 100 53,700 100 93,900 2-27 The actual quantity of surface runoff during the base period was evaluated from records at thirteen key stream gaging stations. Where records -were not continuous over the base period, estimates for the miss- ing seasons -were made by correlation with nearby stations. Unmeasured runoff was estimated by correlation with runoff at a key station or from rainfall-runoff relationships. Table 8 presents measured and estimated seasonal runoff for the base period at the thirteen key stations. 2-28 CO PQ B CD 0) O CD CO Q. 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Ot>-r>-LA-d-LfNI>-OOsCM COONHUxnJHt^O-^HCvl rocOCM .^.^.^ #\ 9* ^ n.n «% ^ «\ •* n -3sO OHHfAO-OsHvO r-lCM rH CM H -=T CM _d-_=f H H o O o -3 Os sO •V •V 1A 1A rH CM 5 C*-cO OsOiHCAJ rr\_3-u\sO O-cO OsOH rncAfA-d--3/-d'-3"-=f-ct-d , -3'-3-d-XAUA 1 J I I I I I I I I l I I I I sOr*-aOOsOrHCM-COOsO rncAfAcA«j , -d'-cf-d--d-d--d--d--=r-3\A OxOsOsOsOsOsOsOsOsOsOsOsOsOsOs r-ir-ir-ir^r-ir-\r-lr-iT-\r-ir-ir-\r4i-ir4 2-30 Historically, foreign water has entered the Santa Clara River drainage area through release from the Los Angeles Aqueduct or as a result of spill from the Bouquet Caiyon terminal reservoir on the aque- duct. Harold Conkling, Consulting Engineer, in his report entitled "Development of a Supplemental Water Supply for Zone 2, Ventura County Flood Control District, September, 19h9 u , estimated the monthly accre- tions to the Santa Clara River system from this source for the period from 1925-26 through 19hl-hS>» Estimated amounts for the calendar years 19U8 through 1951 were obtained from the United Water Conservation Dis- trict. These estimates indicate that a total of about 60,900 acre-feet of vjater from the Los Angeles Aqueduct was discharged into the Santa Clara River during the base period* The amounts varied from zero in several seasons to a maximum of about 20,000 acre-feet in 1938-39. Al- though this release contributed to the historical water supply of Ven- tura County, adequate data were not available to determine the quanti- tative effect thereof. Studies did indicate that in most years a sub- stantial portion of the release percolated in the Santa Clara River channel above the Ventura County line. Furthermore, in certain years when releases were made during periods of flood flow, aqueduct water comingled with local waters and passed through Ventura County to the ocean. Although the percolation of aqueduct water above the County line undoubtedly has affected the rising water at the upper limit of the Piru ground water basin, this influence has been estimated to be of small magnitude and has not been considered in this bulletin. Imported Water Imported water comprises a relatively minor item in the 2-31 water supply of Ventura County. Since 19U0, Santa Clara River water has been imported by the Newhall Land and Farming Company from a well field in Los Angeles County near Castaic Junction for use in the Piru ground water basin. About 1,300 acres of land on both sides of the river between the County line and the town of Piru are served by the import. The following tabulation presents the seasonal amount of this import for the period from 1939- k0 through 1950-51: Season Acre-feet Season Acre-feet 1939-1*0 19U0-U 19U1-U2 19U2-13 19U3-UU 19UU-U5 900 1,1*00 1,81;2 1,801 1,682 1,851 19li5-li6 19U6'hl 19U7-U8 191*8-1*9 191*9-50 1950-51 2,053 2,261 2,837 3,182 3,81*0 3,680 Underground Hydrology Regulation and reregulation of the water supplies of Ventura County is accomplished almost entirely through storage in underlying ground water reservoirs. ■ Ble ground water supplies are found in the valleys and some hill areas in the southerly portion of the County, occurring principally in alluvium and unconsolidated sediments, and to a lesser extent in consolidated and fractured rocks of sedimentary and volcanic origin. These underground reservoirs are replenished by percolation of surface waters, both in natural channels and in spreading grounds constructed for this purpose, by deep penetration of precipi- tation and the unconsumed portion of applied irrigation water, and by subsurface inflow from adjacent ground water basins. Disposal of ground water supplies is effected by pumped extractions, by effluent discharge and consumptive use of native vegetation in areas of high ground water, and by subsurface outflow. 2-32 In connection with the discussion of underground hydrology in this bulletin, the following terms are used as defined: Key Well — A well chosen for study because it indicates specified ground water characteristics that are considered representative of a given ground water basin or aquifer, or a portion thereof. Free Ground Water — This generally refers to a body of ground water not overlain by impervious materials, and moving under control of the water table slope. In areas of free ground water, the ground w°ter basin provides storage to regulate available water supplies. Changes in ground water storage are indicated by changes in ground water levels. Confined Ground Water — A body of ground water overlain by material sufficiently impervious to sever free hydraulic connection with over- lying water, and moving under pressure caused by the difference in head between intake and discharge areas of the confined water body. Specific Yield — This term, when used in connection with ground water, refers to the ratio of the volume of water a saturated material will yield by gravity to its own volume, and is commonly expressed as a percentage. Ground water storage capacity is estimated as the product of the specific yield and the volume of material in the depth intervals considered. Spec ific Capacity — The number of gallons per minute produced by a pumping well per foot of drawdown. Drawdow n — The lowering of the water level in a well caused by pumping, measured in feet. Results of investigation of the 17 major ground water basins which have been identified in Ventura County are discussed in this section. In addition to the 17 major basins, there are several other ground water basins in the County which, because of their 2-33 relatively small storage capacity and minor present utilization, have not been given detailed consideration in this bulletin. Plate 11, entitled "Ground Water Basins", shows the location of .each Of the 17 basins, and of selected key wells employed in analyzing the basin characteristics. The wells are numbered by the system utilized by the United States Geological Survey, according to the township, range, and section subdivision of the Federal land survey. In the portions of Ventura County not so subdivided, the township, range, and section lines have been projected. Under the system, each section is divided into liO-acre plots, which are lettered as follows: D C B. A E F G H M L K J N P Q R Wells are numbered within each of these i;0-acre plots according to the order in which they are located. For example, a well having a number 3N/21W-20M1 would be found in Township 3 North, Range 21 West, and in Section 20. It would be further identified as the first well located in the U0-acre plot lettered M. All well numbers in Ventura County refer to the San Bernardino Base Line and Meridian. : The 17 major ground water basins of Ventura County vary con- siderably in economic importance, depending on their usable storage capacity, areal extent, seasonal recharge, and the ease with which ground water is yielded to pumping wells. The present studies of underground hydrology included investigation of the geologic charac- teristics of each of the basins, together with quantitative analysis of replenishment 'and disposal of ground waters therein. 2-3U The geologic investigation included collection and analysis of prior geologic reports and maps, supplemented by discussion with geologists familiar with various portions of the County. Drillers logs for 1,3>3U -water wells and 138 oil wells were collected and analyzed. These data, together with additional information obtained by field surveys, were utilized in preparing Plate 10, entitled "Areal Geology", Plates 12 -A, 12-B, and 12-C, entitled "Geologic Sections", and Plate 13, entitled "Diagrammatic Sketch of Oxnard Plain and Oxnard Forebay Basins". The locations of the geologic sections are shown on Plate 11, Aquifers of significance in ground water pumping were identi- fied from well data, and are shown on the geologic sections. Boundaries of ground water basins were established from geologic evidence, and from analysis of the occurrence and movement of ground water as depicted on the representative ground water contour maps listed in the following tabulation: Plate Number Title lli-A, B, C. Lines of Equal Elevation of Ground Water, Fall of 1936. 15>-A, B, C. Lines of Equal Elevation of Ground Water, Spring of 1°UU» 16-A, B, C. Lines of Equal Elevation of Ground Water, Fall of 1951. 17 -A, B, G. Lines of Equal Depth to Ground Water, Fall of 1951. 18 -A, B, C. Lines of Equal Change in Ground Water Elevation, Fall of 193 6 to Fall of 1951. 19-A, B, C. Lines of Equal Change in Ground Water Elevation, Spring of ±9hh to Fall of 1951. 2-35 Estimates were made of specific yield of the water-bearing formations and of storage capacity of the ground water basins. Methods and procedures utilized in preparing these estimates are described in Appendix B. From these data, and from information on fluctuations of the level of water in wells, changes in ground water storage occurring in ground water basins during selected periods of hydrologic signifi- cance were estimated. Plate 20, entitled "Fluctuation of Water Levels at Key Wells", presents hydrographs of ground water elevation at 18 key wells in IJ4 of the 17 major ground water basins. Plate 21, entitled "Relationship Between Water Levels at Key Wells and Ground Water Storage Depletion", shows graphically the relationship between ground water storage depletion and the elevation of the ground water surface at key wells in Ojai, Piru, Fillmore, Santa Paula, Oxnard Forebay, and Simi Basins. \ Water level measurements utilized in preparing all plates relating to the occurence and movement of ground water and fluctuations of ground water levels, were obtained from the Ventura County Water Survey. The effects of draft on and replenishment of the ground water basins were analyzed for the base period, from 1936-37 through 195>0-51, in an attempt to ascertain how and to what extent the basins could be utilized to regulate available water supplies to meet present and probable future water requirements of Ventura County. These studies included analysis of data on precipitation, surface runoff, and records of diversions of surface flow from principal streams in the County. Estimates were made of consumptive use of water and of ground water extractions as described in Chapter III. Recharge of ground water basins from stream channel percolation was estimated from data appear- 2-36 ing in Division of Water Resources Bulletin No. I46, modified and supplemented in accordance with more recent information including measurements made during the investigation. Where adequate data were available, subsurface inflow to and outflow from the ground water basins were estimated by means of either the "rising water" or "slope-area" methods, or both, descriptions of which are included in Appendix B. - The ensuing discussion presents pertinent data and the results of studies for each of the 17 major ground water basins, As will be noted, the degree of detail to which these studies were conducted varied among the basins, depending on the relative importance of the basin and the availability of basic hydrologic data. Ventura Hydrologic Unit I Four major ground water basins have been identified in the Ventura Hydrologic Unit. These basins, designated Upper Ojai, Ojai, Upper Ventura River, and Lower Ventura River, comprise a total surface area of about 15,650 acres. The remaining lands of the unit are prin- cipally underlain by formations of low permeability which dc not yield water readily to wells. Table 9 summarizes certain physical charac- teristics of the four ground water basins. 2-37 OS pq EH x> ci _ H H -d -H a CD -P S co ft H CO C C •H M(h rH O -H -P cd Sm H h a CO m -H CD 3 W cu £ > a> o cd O CO -P -P u x) o h o Pfl tH £ CTJ CD CD CD B P ^ CO Ch Ch •P -P $n 3 (o ex Go co cd X 1.3 w CD •H ft co rt ft |>5 W co •H CO »> CD cd H CD o m cd < a a CO cd PQ o XI cu cj o o | o o fA I o ■a 05 CD CD O o + c -p CO 'g Cj •H P o 0) rH CD rH rH W Ph CIS co •H cd •1-5 O H CD ft & O 3 o 8 1 •H >» !? B H 0) co <3 c __ x? XI CD a •H 'H t>5 CD -P «H H 2 CJ CJ H -H S CD O CTJ «H CO O O CJ o o CO C o O ,2 & 2 rl O u> o CD Xi S cj cd to o B O P 12 •£ *C fl w > CD -H P O CD H Q 5^ « "LA 2-38 •H CO •1-5 O o o rH I o x) CO o o •H > O CD H OHrj OJ Ol, cd -P. -P C CO CD- co CO X> I a o I o o rH I o o o 8 8 o o CA r— H H 1 o i o 1 O w XJ CO X) «H CD 10 XJ > C M X3 3 U XI CJ as co bb CD CD CD i-Q ft CO CD ft CD CO cd Jm co bb CD C CD cd O o -p -p CD U CD H H Oj Oh cd CO o O O o XA -3 ON c~- On O ON vO r> •% •> • rH vO -Ct CM a -p •P c: CJ CD CD > u > ^ CD CD u > Ih > CD -H CD «H ftcd ^ « ft O J3 l~} CD trjO X o CD > CD ■H h CD lo o •H Im O -P (0 •H X ch O CD CJ O N Upper Ojai Basin . Upper Ojai Basin, with a surface area of about 1,950 acres, lies in the northeasterly portion of the Ventura Hydrologic Unit, at elevations varying between 1,200 and 1,600 feet above sea level. Surface waters in the basin drain both to the west through Lion Canyon into San Antonio Creek, and to the east via Sisar Creek to Santa Paula Creek. Water-bearing materials in Upper Ojai Basin consist of Recent and Pleistocene gravels, sands, and clays, and to a lesser extent weathered consolidated sediments of Tertiary age. The average thickness of the water-bearing materials has been estimated to approximate 60 feet, attaining an estimated maximum depth of about 300 feet near Sisar Creek. In general, ground water in the basin is unconfined, with a direction of movement conforming to the surface slope, as shown on Plate 16-A. The basin is replenished by deep penetration of precipitation, by percolation of surface water in minor watercourses, and by percolation of the unconsumed portion of water applied for irrigation and other uses. Ground water effluent appears in springs at both the easterly and westerly extremities of the basin. Ground water in Upper Ojai Basin is presently utilized to meet relatively minor domestic and irrigation requirements, Wells yield between 10 and 200 gallons per minute, with an estimated average yield of about S>0 gallons per minute. No quantitative estimates were made of the storage capacity of the basin, nor of historic change in ground water storage therein. It is considered probable, however, that the basin is presently utilized to about the maximum practicable extent. 2-39 Ojai Basin . Ojai Basin, with a surface area of about 6,0l|0 acres, lies in the northerly portion of the Ventura Hydrologic Unit and to the northwest of Upper Ojai Basin, at elevations varying from about 700 to more than 1,200 feet above sea level. Surface waters in the basin drain southwesterly in San Antonio Creek to the Ventura River. Water-bearing materials in Ojai Basin consist of Recent and Pleistocene alluvium, which is flanked and underlain by consolidated sediments of Tertiary age that yield minor amounts of water. The allu- vium is estimated to extend to a depth of at least 700 feet near the center of the basin. Geologic sections E-E' and F-F' on Plate 12 -A depict the configuration of the base of the alluvium. Ground waters throughout the basin are essentially unconfined, although lenses of clay result in localized confinement of portions of the ground water body. During periods of high ground water levels, flowing wells have been reported in the southwesterly portion of the basin. The direction of normal ground water movement is west and south, with convergence toward the point of outflow of San Antonio Creek, as shown on Plates lU-A and 1S>-A. However, during drought periods the direction of movement in the southwesterly portion is reversed, as shown on Plate 16-A. Wells supplying requirements of the basin are reported to yield from 100 to 600 gallons per minute, with specific capacities varying from 3 to 20. Sources of replenishment to ground water in Ojai Basin are percolation of surface waters on the alluvial cones at the mouths of Horn and Senor Canyons, in the channel of San Antonio Creek, and other minor watercourses, deep penetration of precipitation, and percolation of the unconsumed portion of water applied for irrigation and other uses, In addition, in 1952, an estimated 3,270 acre-feet of water were 2-1*0 delivered to Ojai Basin from Matilija Reservoir. This water was largely- spread and percolated at grounds constructed by the Ventura County Flood Control District in the north-central portion of the basin, although minor quantities of the import were sold directly to a few users. Ground water disposal from Ojai Basin is effected by pumped extractions to meet beneficial consumptive uses of overlying irrigated and urban lands, by consumptive use of phreatophytes, and by effluent discharge into San Antonio Creek. Because of its relatively small storage capacity as related to ground water replenishment and disposal, Ojai Basin is quickly recharged during wet periods, and conversely is rapidly depleted during periods of drought. Seasonal and cyclic fluctuations of the ground water surface at key well number UN/22V/-f>Ll are shown on Plate 20. Pumping lifts exhibit wide variation from wet to drought periods. In the fall of 19$l s some users in the basin were pumping against heads in excess of 300 feet. Lack of adequate hydrologic data precluded the evaluation of all items comprising water supply and disposal in Ojai Basin. Studies were made of the effects of draft on and replenishment of the ground water body during the drought period. In the spring of 1°UU, Ojai Basin was essentially full, and effluent discharge was occurring at its westerly extremity. From the spring of 19hh to the fall of l°£l, dis- posal of ground water exceeded recharge, and ground water storage in the basin was substantially dewatered. Estimated ground water storage depletion during the seven-year drought period amounted to about 28,000 acre-feet. Total consumptive use of water on overlying lands, including that of precipitation, was estimated to have been about 71,000 acre-feet. Consumptive use of applied water during this period was estimated to 2-ia have been about 28,200 acre-feet. The net retention of direct precipi- tation on the ground water basin, and of tributary surface inflow during the period was determined as a differential in solution of the equation of hydrologic equilibrium, and was estimated to have been about ii3,000 acre-feet. The hydrologic equation states in effect that the sum of the items comprising the water supply of a given hydrologic unit or area must be equal to the sum of the items of water disposal plus or minus the change in ground water storage. As shown by sections E-E' and F-F 1 on Plate 12-A, Ojai Basin has a concave configuration, with the depth of alluvium considerably greater in the center than at the peripheral margin. By the fall of 19hl , water levels had so lowered that some wells near the margin had gone dry. Because of this historic limitation in its utility, it was estimated that the usable storage capacity of Ojai Basin, under present pattern of pumping, is equal to the computed total decrement in storage from the spring of 19hh to the fall of 19hl , or about 10,900 acre-feet. Total storage capacity of the basin was estimated to be in the order of 70,000 acre-feet. The relationship between unwatered ground water storage in Ojai Basin and elevation of the ground water surface at key well number liN/22VJ-5I«l is shown on Plate 21. Upper Ventura River Basin . Upper Ventura River Basin essen- tially comprises the alluvial filled Ventura River Valley above the diversion weir of the City of Ventura at Foster Park. The basin has a surface area of about h,990 acres, ranging in elevation from 200 to more than 800 feet above sea level. Surface waters drain south toward Foster Park, Water-bearing materials in Upper Ventura River Basin consist of deposits of gravels, sands, and clays of Recent and Pleistocene age. 2-U2 These deposits are flanked and underlain by consolidated sediments of Tertiary age, which form the bottom and sides of the basin. Section E-E' on Plate 12-A shows the general structure and shape of the basin. For study purposes, Upper Ventura River Basin was taken to comprise only the area underlain by alluvium. Geologic examination during the course of the investigation indicated that depth of the alluvium varies from about 60 feet northwest of Meiners Oaks, to about 80 feet at Foster Park. Maximum depths of over 100 feet occur at various points between Meiners Oaks and Foster Park. Ground water occurs primarily in the alluvial deposits of Upper Ventura River Basin, and is unconfined. However, minor quantities of water are yielded to irrigation and domestic wells drilled into the Tertiary formations. In general, direction of ground water movement conforms with the slope of the Ventura River bed, as shown on Plates lii-A, l£-A, and 16-A. It was estimated that the total storage capacity of the basin is in the order of 10,000 acre-feet. Although it was not possible to evaluate the usable storage capacity of the basin, it is believed to comprise a relatively small portion of the estimated total capacity. The greatest number of wells in the basin are used for domestic and minor irrigation developments. A few large irrigation wells yield an average of about 600 gallons per minute, with specific capacities varying from 10 to 200. Percolation of flow in the Ventura River channel is the pri- mary source of recharge to Upper Ventura River Basin, with percolation of direct rainfall, of the unconsumed portion of water applied for irrigation and other uses, and of subsurface inflow from the flanking Tertiary formations comprising secondary sources of supply. Since 191*8, discharge in Matilija Creek and percolation therefrom has been affected 2-U3 by operation of Matilija Reservoir. Ground water in the basin is dis- posed of by pumped extractions to meet beneficial consumptive uses on overlying and adjacent lands, including extractions by the City of Ventura at its well field upstream from the diversion weir at Foster Park, by consumptive use of phreatophytes, and by effluent discharge and subsurface outflow at Foster Park. The subsurface flow at the east end of the diversion weir at Foster Park was estimated to average less than 100 acre-feet per season. The limited storage capacity of Upper Ventura River Basin provides only short-term retention to surface runoff, and furnishes but little carry-over storage during a period of drought. The relatively steep slope of the basin results in rapid drainage south toward Foster Park. Ground water levels in the basin respond quickly to changes in the rate of surface flow in the Ventura River. Percolation of water originating in Matilija and North Fork of Matilija Creeks in the Ventura River channel was estimated from percolation diagrams presented in the report entitled "Safe Yield - Matilija Reservoir, May, 19U8" by Harold Conkling, Consulting Engineer. Surface flow in these two streams and percolation to ground water from them meet the greater portion of the water requirements of lands over- lying and adjacent to Ventura River Basin and the City of Ventura. Examination of water level measurements available from the Ventura County Water Survey, together with analysis of inflow to the basin from Matilija Creek and the North Fork of Matilija Creek, and surface outflow from the basin as measured at the gaging station on Ventura River near Ventura, indicated that during the drought period the basin was substantially full until the spring of 19hl > and that percolation to the basin was adequate to satisfy demands of ground water users, 2-1* including the pumping requirements of the City of Ventura. At the same time, surface discharge was sufficient to meet requirements of surface- supplied lands upstream from Meiners Oaks, and to meet the remainder of the City's requirements. Subsequent to the spring of 19h7, however, use of water from the basin exceeded seasonal recharge, and water levels progressively dropped until the fall of 195>1, when the basin was sub- stantially dewatered. Recharge during the wet season of 1951-52 essentially filled the basin. It has been stated that relatively high rates of surface flow prevailed in Ventura River Basin in most months during the wet period and during the portion of the drought period from 19UU-U5 to the spring of 19h7 » Also, requirements for water by overlying and adjacent users of ground water supplies, and by riparian surface diverters including the City of Ventura, were satisfied during this time of ample surface flow. For these reasons, no attempt was made to quantitatively eva- luate recharge to and disposal of ground water supplies in Upper Ventura River Basin prior to the spring of 19ii7. From the spring of 19h7 through the season of 195>0-5l, the average seasonal percolation in Upper Ventura River Basin was estimated to have been about 3,100 acre-feet. Present use of water by overlying and riparian users, including the City of Ventura, was estimated to be about 7,700 acre-feet per season. During a wet period, such as that which occurred from 1936-37 through 19U3-UU, it was estimated that requirements of these users would be satisfied. During a drought period, such as from 19kh'kS through 1950-51 , it was estimated that, without impairment by operation of Matilija Reservoir, about i;,900 acre-feet of water per season on the average would be available to the users. Under these circumstances, about 3,300 acre-feet per season would have been 2-15 available during the period from the spring of 19U7 through the season 1950-51* This estimate does not include usable supplies available in ground storage in Upper Ventura River Basin at the beginning of the period, which, as stated previously, were estimated to be of small mag- nitude. The estimated seasonal runoff of the Ventura River at the gaging station, Ventura River near Ventura, that would have occurred during the base period with the present pattern of land use and pre- vailing water requirements, and with Matilija Reservoir in operation, is shown in Table 10. 2-U6 TABLE 10 ESTIUATED SEASONAL RUNOFF OF VENTURA RIVER NEAR VENTURA DURING BASE PERIOD, WITH PRESENT PATTERN OF LAND USE AND V/ITH MATILIJA RESERVOIR IN OPERATION Season : Acre-feet 1936-37 97,900 1937-38 186,600 1938-39 ■• 17,300 1939-1*0 8,900 19U0-U1 253,300 19hl-h2 19,100 19U2-U3 13U,000 I9k3-Uh 72,500 19hh-h5 28,200 19h5-U6 21,600 19ii6-ii7 9,800 19U7-U8 19U8-U9 19U9-50 2,hOO 1950-51 Average for base period, 1936-37 through 1950-51 56,800 Average for wet period, 1936-37 through 1914.3-UU 98,700 Average ■ for drought period, 19WW*5 through 1950-51 8,800 Lower Ventura River Basin , Lower Ventura River Basin essen- tially comprises gravels, sands, and clays of Recent and Pleistocene alluvium in the Ventura River bottom lands between Foster Park and the ocean. The basin has a surface area of about 2,670 acres, varying in elevation from 200 feet above sea level to sea level. Surface waters drain south in the Ventura River channel to the ocean. 2-1+7 Depth of the alluvium in Lower Ventura River Basin varies from about 80 feet at Foster Park to in excess of 100 feet near the mouth of the Ventura River. The alluvium is flanked and underlain by consoli- dated sediments, most of which are of Tertiary age. Under natural conditions, this basin was undifferentiated from the Upper Ventura River Basin, but it has been treated separately herein because of the impedance to ground water movement effected by the artificial subsurface barrier at Foster Park. Near the mouth of the river, the alluvium of Lower Ventura River Basin is underlain by water-bearing deposits of the San Pedro formation. It is believed that there is little if any hydraulic connec- tion between the two formations. It is indicated that the San Pedro formation is recharged by percolation of tributary runoff and direct precipitation on its outcrop area in the hills northeasterly of the City of Ventura. The San Pedro formation is considered to be contained within Mound Basin, most of which is included within the Santa Clara River Hydrologic Unit. Thus, near the mouth of the Ventura River, Lower Ventura River Basin overlaps Mound Basin, with free hydraulic connection between the two severed by impermeable clays which confine the ground water in the latter basin. Ground water in Lower Ventura River Basin is of such inferior mineral quality that the basin is not presently utilized. Lands requiring water service overlying the basin are either served by the City of Ventura or pump ground water from the underlying San Pedro for- mation. At the present time, an estimated 600 acre-feet of water per season are so extracted on the average. Of this amount, about 100 acre- feet per season are exported for domestic and industrial use in the Rincon Subunit, northwest of the Ventura River, 2-iiB Santa Clara River Hydrologic Unit From the economic standpoint, the seven major ground -water basins identified in the Santa Clara River Hydrologic Unit are the most important in Ventura County. These basins, designated Piru, Fillmore, Santa Paula, Oxnard Forebay, Mound, Oxnard Plain, and Pleasant Valley, comprise a total surface area of about 125,700 acres, varying in elevation from sea level at the mouth of the Santa Clara River to about 800 feet above sea level in the river channel at the easterly county line. Utilization of water extracted from ground water storage in the Santa Clara River Hydrologic Unit meets over 90 per cent of the requirement of an estimated present net irrigated area of about 83*000 acres, as well as the entire requirement of the communities of Oxnard, Port Hueneme, Fillmore, Piru, Saticoy, and other smaller urbanized areas. A small portion of Eastern Basin, a large ground water basin which lies primarily in Los Angeles County, is included within Ventura County immediately east of Piru Basin. However, because of the rela- tively small areal extent of Eastern Basin within Ventura County, detailed analysis and discussion thereof has not been included in this bulletin. The Piru, Fillmore, Santa Paula, and Mound Basins overlie the Santa Clara River syncline, which is a deformation in the San Pedro and older formations, and is of considerable significance to the hydrology of the basins. Ground water occurring in the Piru, Fillmore, Santa Paula, and Oxnard Forebay Basins is unconfined, whereas that occurring in the pumped aquifers of the Mound, Oxnard Plain, and Pleasant Valley Basins is under pressure caused by confining clay beds of low per- meability. The unconfined ground water basins are replenished by 2-U9 percolation of flow in the Santa Clara River and its tributaries, per- colation of direct precipitation, artificial spreading and percolation of surface waters, and by percolation of the unconsumed residuum of water applied for irrigation and other uses* The pumped pressure aqui- fers in the Mound, Oxnard Plain, and Pleasant Valley Basins are largely supplied by subsurface flow from areas of free ground water. Ground water in the seven major basins of the Santa Clara River Hydrologic Unit is disposed of by effluent discharge to lower basins, by pumped extractions to meet beneficial consumptive uses, by consumptive use of phreatophytes in areas of high ground water, and by subsurface flow to lower basins and to the ocean. The effects of draft on and replenishment of ground water basins in the Santa Clara River Hydrologic Unit were analyzed as they would be with the present pattern of land use and under conditions of water supply and climate that occurred during the base period. The general method of analysis employed in these studies involved evaluation of the several items of water supply and disposal, and solution of the equation of hydrologic equilibrium to determine changes in ground water storage. Estimates of tributary surface inflow were made by correla- tion with measured flow at key gaging stations, records for which were presented earlier in this chapter. Estimates of the quantity of precipitation falling on absorptive areas have also been presented in this chapter. The nature and extent of land use within and adjacent to each of the basins were determined from the results of land use surveys conducted during 19k9~50. Consumptive use of water and estimates of ground water extractions were determined as described in Chapter III. Records of surface diversion to irrigated and urban lands were obtained from various sources, and employed as required in the analyses. Stream 2- £0 channel percolation was estimated from diagrams presented in Division of Water Resources Bulletin No. 1*6, as modified by the United Water Con- servation District in light of more recent percolation measurements. Additional percolation measurements made during the investigation con- firmed the validity of the modified diagrams. Subsurface inflow to and outflow from each of the unconfined ground water basins were estimated by the rising water method, and the reasonableness of the results was checked by use of the slope-area method. Both methods are described in detail in Appendix B. Inflow from and outflow to the ocean along the coastal front of Oxnard Plain Basin were estimated from parameters established from records of piezometric levels, and from estimates of ground water extractions. Table 11 summarizes certain physical characteristics of the seven major ground water basins in the Santa Clara River Hydrologic Unit. 2-51 a 3 CQ CO x5 a CD O -P ^ F? ^ H ^ -p -P 2^ co p., to co "d -P <3 -P CO ■5 -o d rH O T3 CD -H CD -H CO C MttH O CO H r-l H *-i -H CD H CD ? crj > ch U) cO o co O d O •H •H — O T3 P iU O 0) ?H -P d o o bo nJ o o CO CD CQ 0) 43 +> CD Ch CD •H O a* -P -H cO d co ,c -H W -P «H o CD O T3 O CO +3 Jh CD (X) CD CD CD tH CO <+H <»H ctf O -P ■H cO rH CO CO •H CD U cr 1 (t. cO to d •H ?-. CO co • 3 >U CD fc -p p CO «H P 1 CO •P CO •P d T) (D O •» CD CD M-H* O ■P CO Cu 13 A ft -H H ^ M CD O CO CD CD -H a CO C ■H £ O CO CO •v CD CD O k CO "a d •H to cO CQ CO CD d d o o a co O O CM I o 'd -d 0) CD 5 3 •H "2 'a o o o o d a + o o o LTv CO CM 1 O o o T3 CD a O p 5* H ■a a 3 •H -H -P «H d d CD O CO O co d uq P o o CM i o ■H P d CD CO o CO c w 3 + 8 co o CM vO CM CM d OO H rl •H fa o o o CM •Lf\ H CO CU CO •g cO CO 8 •H O O +• + + + o o O o o o O o o 8 8 CM o CM O CM o XT\ 1 •\ 1 ** 1 •\ i o rH o rH O H rH CO CO -d -d CD CD «H CD CO -d > CO S -H CO S -H u | CO CO si d co d C T3 d fi X) CO co w CD CD CD P-i CO 3 CD CD O, CO CD d 0) CD $ •d d -d d T3 d d CD co o o g o d CD cO O O | O 1 CD -P d co > CU d co 04 d CU cu CD -H d CD -H d CD •H d CO CD H d O CD H S O CD rH 9 § CD rH rH cO CD rH rH CD H H « Oh CO co ed a, ci co CcJ CU f0 CO CO 8 c^\ •v CM H s 2-52 CO o M E-< CO H E-t H •^ O pq H o o O S fa H O CO 03 «H bo ctf o «H o CD d 3 g o CD P !h •H u o cd +3 4 £ fort CJ £ a O fa o O O o ^ CO -d CO U s x: u -h H Jh •H MJ) O CD CD +3 •H > CD •h a CO CD CtJ Ph >S fa j£ CO d •H co »\ CD ctJ U CD O £ CtJ < - d •H •3 (0 ctJ fa o o o o o 1 o o o H 1 ON 0\ -=t •x l H X) CD d •H O I O 1A CM I o o H O 1A CM I O o d o fa -H O -P -P o i a 53 fa CD Xl d rt CD 03 O O -P -P co !> CD >H P O (DH ca H H 03 fa rt •LA H O r>- H *\ etJ XJ CD ctJ O flfa ■d CD O o s o lA I o o •LA I o -d CD CD fl & o o to u CD bp 1 i 3 'd a 1 -p *♦ CD ctJ CD co ^ ,a CD P O H CD H 03 aJ O mD d •H ctJ H fa •d ctJ •d s O o 8 CM I o 1A CM o o !h CD •H CtJ a CD o a O P CO t> •H P fa CD (H & fa d U CD TJ CD o o o o fA I o o o o Os «\ H I O o vQ d p 1>j o co H ctj -d •H CD •p d d ;H CD H co d CO o fa o o o I O -d -P !W CD O "d ctJ d PS S H ^ -p R CtJ CO O O CD CD CD K CO X ^ d o CD CD fa fa H CD ■d d o d CD -8 CtJ O o CD -p -p fa d co CD O -H C O p CtJ •H CD -H P O CD rH 03 fa aJ co •\ fA CM -P d oj CO 05 CD rH fa CD rH rH CtJ > O o o o o fA I o o o •LA H l 8 d o oJ O o fa o CD fa d rt co CD bo X3 o H CD H 5h CD 15 o •H JH O -P CO 20 acres, and surface elevations in the Santa Clara River channel range from about 800 feet above sea level at the eastern extremity of the basin to about U70 feet at the western extremity. Surface waters drain westerly in the river channel and southwesterly in Piru Creek, a principal tributary. Water-bearing formations in Piru Basin include Recent and Upper Pleistocene alluvium, underlain by the older San Pedro formation. The alluvium attains depths of 8$ to 200 feet. From analyses of oil well logs, the San Pedro formation is estimated to extend to depths as great as U,000 feet, although the maximum depth of the aquifers pres- ently utilized is about 1,000 feet. As shown on geologic section J-J f on Plate 12-A, the San Pedro formation does not outcrop in Piru Basin. Also shown on section J- J' are the San Cayetano and Oak Ridge faults, which separate the San Pedro formation from flanking nonwater-bearing Tertiary formations. Ground waters found in Piru Basin are unconf ined. As shown on Plates lit-B, 13>-B, and 16-B, ground water generally moves to the west in the direction of the surface slope. The water table slope flattens toivard the westerly extremity of the basin, where the cross sectional area of the San Pedro formation is reduced by warping of the Santa Clara River syncline. Historically, this constriction has resulted in effluent discharge from the ground water body. The westerly boundary of Piru Basin was arbitrarily drawn at the estimated section of maximum rising water, but could have been drawn equally as well a short distance to the east or west of the assumed line. Most wells in the basin have been drilled to the San Pedro formation, and yield from 600 to 2,000 2--A gallons per minute, with an estimated average yield of about 800 gallons per minute. Specific capacity of wells averages about 70. The esti- mated weighted average specific yield of water-bearing materials in the basin, in the range of depth between the highest and lowest historic water levels, is approximately 17 per cent. Ground water storage in Piru Basin is replenished by natural percolation of Piru Creek, Hopper Creek, and Santa Clara River water, and by spreading and percolation of Piru Creek water at grounds con- structed by the Santa Clara Water Conservation District near the town of Piru, which are now operated by the United Water Conservation Dis- trict. Percolation of direct precipitation, and of the unconsumed portion of water applied for irrigation and other uses, including water imported from Eastern Basin, also replenishes the ground water of Piru Basin. Ground water is disposed of by pumped extractions to meet bene- ficial consumptive uses on overlying and adjacent lands, by exportation to Fillmore Basin, by consumptive use of phreatophytes, by effluent discharge, and by subsurface outflow. Records of measurements of ground water levels in Piru Basin are available since the late 1920's. Seasonal and cyclic fluctuations of the ground water surface at key well number iiN/l9W-25Ll|. are shown on Plate 20. As depicted by this hydrograph, ground water levels in the basin respond rapidly in accordance with the relative wetness of a given season. The ground water surface at this well had a recorded maximum elevation of about 572 feet in the spring of 19hk, and a minimum elevation of about 1*14.8 feet in the fall of 1951. Substantial recharge to the ground water body during the wet season of 1951-52 resulted in a sharp rise in the ground water surface at this well, to an elevation of about 536 feet. Ground water storage depletion in Piru Basin at the 2-55 beginning of the base period, in the fall of 1936, was estimated to have been about 5>1,000 acre-feet, while estimated storage depletion in the fall of 1951 was about 9U,300 acre-feet. It was further estimated that the basin was essentially full in the spring of 19U5. The rela- tionship between elevation of the ground water surface at well number l;N/l9W-2!?Lii and ground water storage depletion in Piru Basin is shown on Plate 21. By the summer of 1936, following a dry period, nearly all wells pumping from the alluvium on the south side of Piru Basin had gone dry. As a result, overlying users drilled wells nearer the river and into the San Pedro formation, where adequate water supplies were obtained. From examination of geologic section J- J' on Plate 12-A, it appears that these overlying users could have drilled much deeper wells at the original sites and intercepted the water-bearing San Pedro for- mation. For these reasons, it is believed that the utility of Piru Basin is limited by factors of economic pumping lift and mean seasonal recharge, rather than by storage capacity or configuration of the basin. Analysis was made of water supply and disposal in Piru Basin during the base period to determine changes in ground water storage, assuming that the present pattern of land use prevailed over this period. Although the method of analysis generally described earlier in this chapter was utilized, the evaluations of certain of the items of water supply and disposal warrant further description. Unmeasured flood flow in the Santa Clara River from Los Angeles County was estimated by correlation with recorded flow at the gaging station on the Santa Clara River near Saugus, maintained by the Los Angeles County Flood Control District. Effluent discharge from Eastern Basin to Piru Basin was 2-56 estimated from data appearing in the report entitled "Development of a Supplemental Water Supply for Zone 2, Ventura County Flood Control District, September 19h9" } by Harold Ccnkling, Consulting Engineer, and in biennial reports on hydrologic data prepared by the Los Angeles County Flood Control District. Minor tributary surface inflow was estimated by correlation with recorded flow of Hopper Creek. Percola- tion of surface inflow to the ground water basin was estimated from records of diversion to the spreading grounds near Piru, and from percolation diagrams indicating losses in Piru and Hopper Creeks and the Santa Clara River channel, for various rates of discharge. Exports from the basin were taken from the records of the Sespe Land and Water Company, Southside Improvement Company, and the State Fish Hatchery. As the latter entity did not export water prior to 19U8, the probable exportation that would have been made over the base period was estimated by extending the exports of record. Effluent discharge from the basin was estimated from the determined correlation between measured rates of discharge and slopes of the ground water surface. Flood flow leaving the basin was taken as the difference between total surface inflow and percolation in the stream channels and in the spreading grounds near Piru. The hydrologic studies were conducted on a monthly basis over the base period, commencing with an assumed basin storage depletion in the fall of 1936 of 9b, 300 acre-feet, which was the estimated actual depletion in the fall of 1951. It was found that under conditions of the study, the basin would have first filled in February, 1938, and would have remained essentially full, with the exception of the seasons of 1938-39 and 1939-^0, until the spring of 19b5. From that time until the fall of 1951, disposal of water in the basin would have exceeded 2-57 recharge, and basin storage would have again been depleted in the amount of 9h t 300 acre-feet by the fall of 193>1. Since this storage depletion is equal to that which actually prevailed in the fall of 1951* it is indicated that subsequent to the last filling of the basin in the spring of \9hSi conditions assumed for the study were equivalent to actual historical conditions. A seasonal summary of the foregoing hydrologic analysis of Piru Basin is presented in Table 12. 2-58 o o cr UJ Q_ CO OD en => o — = CO «* o CD Z —I O t- CO — «I «x l— a. O CO UJ uj cr CO a. CC X o h- H- — co 3 o CO «I UJ CO a z K ►- o UJ < to H UJ «x < cs Z UJ 3 o — • UJ I- z > < — — i- to 1- lk ■a «t a. O a. co _i C _ •«£ 3 o z CO CO Ul O o z ce a. o O a. a o Ul te cc — Ul UJ u. -J <- 1- O a. -=c « o- 3 3 < o fr- CO ee X o UJ a. K K UJ UJ o «x 3 u. O cc _J => k. CO »- CO 3 3 O CO •« ■• •• •• tu 3 u 3 u. m cr »- = 3 CO O M *• M •• •• •J < fr- O fr- CO a CO - •• z 5> o mI a. fr- 0. < 3 t- CO a. cr «H UJ o ►- Ul « cc 5 a. »• M •• •• H. O cc CO o s: a. UJ C »- «« •« • • M u 3 z CO •* •• z o CO UJ •• «• CO ooooooooooocoootp ~oooooo«?>oooo o o o o o _ ro r- oo id o> o '*(DOjCOKN(0LOr~u7) ooooooooooooooo ooooooooooooooo co co co — — lOCM^r^fco^rcoco^-co (DKlOKCfiCONNKSCONNNN ooooooooooooooo ooooooooooooooo f f NSNOOOOIO) -NOIOOIO tniniommmiomifluxouin^io ooooooooooooooo ooooooooooooooo COCDCOC0CDCDC0CDCOCOCOCOCOOCO i^ — _ — _ » — _r _ _ — co co — CMCMCMCMCMCMCMCMCMCMCMCM OOOOOOOOOOOOOOO ooooooooooooooo OlKtCMONOSOStOSO-inn ONOOOiSCONCOtMOilOo- flO » -CDIO SO) (O (OCM — CM — — ooooooooooooooo ooooooooooooooo (ONOifKOjoeiNOjOioTr^ocM It************** (OinKirigKnocQKootsmcoin CMCOr—*3-COC0CM5»-^.CDC©CMCMCM — — CM CO CM CM ooooooooooooooo ooooooooooooooo COOCOOCMOTCDCOCMOTOTCOmtn^- nncoaootOKjiocoNK^'^'iov OOOOOOOOOOOOOOO OOOOOOOOOOOO cnTooooSoomcoNcos — — — —— CMCMCMCOCOCO OOOOOOOOOOOOOOO OOOOOOOOOOOOOOO lONSlO-NV1feO*»-CO»»-COOTtOCOh- ONttintNOCMioioinx — - — CM CO CM CM tt>ScOCOO— NPl^lOtOKCOCDO- uocos-cooto — CMCO^rmcoK-coOTO nconcocoi , CO \ o o m to o o o o o o o CD o o OT o o o o to Ul »- >• o X o a. CM O o CO o o o 2-59 3 3 O 3 « O O «* O o - CO — tv co co Ul ui co ^* all Ul x * to • 1 <9 CD CP 1 1 3 tr c3 Ul CO O 4 CO CO < to CO CO CC |> co 3 — — > a — — Fillmore Basin . Fillmore Basin is" situated,. westerly of and downstream from Piru Basin. The surface area is about 16,870 acres, and surface elevations in the Santa Clara River channel vary from about hlO feet above sea level at the easterly extremity of the basin to about 280 feet at its westerly limit near the City of Santa Paula. Sur- face waters drain westerly in the river channel, and southwesterly in Sespe Creek, a principal tributary. Water-bearing formations in Fillmore Basin include Recent and Pleistocene alluvium having a maximum depth of about 250 feet, under- lain by the older San Pedro formation, which extends to depths as great as 1^,000 feet. As in Piru Basin, aquifers of the San Pedro formation are presently utilised to a maximum depth of about 1,000 feet. The Oak Ridge fault defines the southerly limit of the San Pedro formation, as shown on geologic section H-H 1 on Plate 12-A. With the exception of an outcrop area of about 1,600 acres near the westerly limit of Fillmore Basin, the San Pedro formation is entirely overlain by the alluvium. Ground waters found in Fillmore Basin are unconfined except in certain relatively minor local areas. Ground water moves generally in a westerly direction in conformity with the slope of the ground surface. At the westerly boundary of the basin, the cross sectional area of the San Pedro formation is reduced by local warping of the Santa Clara River syncline. Upstream from the boundary, there is a flattening in the slope of the ground water surface and effluent discharge of ground water prevails most of the time. Near the constriction, there is a steepening of the slope of the ground water surface. Downstream from the constriction, the cross sectional area of the San Pedro forma- tion is greater, with an accompanying decrease in the slope of the ground water surface. The westerly boundary of the Fillmore Basin was 2-60 arbitrarily drawn at the section of estimated maximum rising water. Irrigation \vells in Fillmore Basin yield up to 2,100 gallons per minute, with an estimated average yield of about 700 gallons per minute. Spe- cific capacity of wells varies considerably, but probably averages on the order of 5>0. The estimated weighted average specific yield of water-bearing materials in the basin, in the range of depth between the highest and lowest historic water levels, is approximately 12 per cent. Ground water storage in Fillmore Basin is replenished by per- colation of surface flow in the Santa Clara River, Sespe Creek, and minor tributary streams, subsurface inflow from Piru Basin, deep pene- tration of direct precipitation, and percolation of the unconsumed portion of water applied for irrigation and other uses. Some contri- bution of minor magnitude may occur through lateral underflow of water from adjacent semi-permeable formations. Ground water in the basin is disposed of by pumped extractions to meet requirements of overlying and adjacent lands, by consumptive use of phreatophytes, it is indicated that subsequent to the last filling of the basin in the spring of 19U7^ conditions assumed for the study were equi- valent to actual historic conditions. 2-63 o cc CO CO CC <£ O -J CO a- CO UJ UJ o cc 0. cc — O 3 O CO CO Q CO U-i < 19 Z Ul 3 -t O oo • Si — z — a. o m mm — 4 O I- CD UJ < oe t- z s a: »- cr LU 1- Q- K « «X S O a. u. S o CO — tti >: o UJ «t 3 1- U- o ce -J 3 U- W Z ts — n CO III o 31 -*. o SS88S8 o o o o o o o o o o o o • CM r— — CM ■<»- I I O O Q O O O o o o o o o ootrco— r^co— co I t I CM CO lf> CO 7 7 t 7 888888 S CO C7) to O co - 0)'fl-r-co'op — *r*of»-if)coo'«»-»co cm t — — r- _ -r •«- — — — 88888 CD ^- — O CNJ 8 00QOOOQO oooooooo (C O) V - O 00 O CO CD 'cfio »cotr)in'crco*cr)(MCMir>(o CO CO CO CO CO CO CO CO CO CO CO CO CO CO o o o 8 8 8 CO o o CM OOOOOOOOOOOOOOO ooooooooooooooo (CtOKtO^COOI-lOCOfM— tNlDOO 8 IT) 8 00 O O O CM Q — O ■«■ CM -OOOISOcSON CMCMCMCMCMCMCMCMCM — — — CM — O CM CM O) OOOOOOOOOOOOOOO ooooooooooooooo OCO^-COOQCDCOCMt7)COCOI--h-CO — CO « CO •* — CM •« *r*TTiD'G-TVir)i^LOijr)ir)ioir>ir>ir)co OOOOOOOOOOOOOOO OOOOOOOOOOOOOOO O-oxotocnoiTion'CN'cr-oj »0)f(MlftO)000- OinOllSNOOllOOOcScM- — — »r t«- — co co — — o o o o If) 8 o o IT) o o o o If) Ok oo V § OOOOOOOOOOOOOO OOOOOOOOOOOOOO — CMCOCDIf)COO)COCMO)QOlf)Olf) — 0*o)o>NOWf»coM>-» — cm if) O)0>C0CT)00lf)COO , 5' ,, ''"CMlf)cf)C0CO CM'*— F— — T ^r _ _ _ OOOOOOOOOOOOOOO OOOOOOOOOOOOOOO lf)0)OC0CMC0OCDC0CMl>~ CO— CM o)CDCMO)i- — oo cm - oonnoxM CO CO CM — if) CM CO CO CM — CM — — OOOOOOOOOOOOOOO OOOOOOOOOOOOOOO * TSNCMCO OOlO) — CM O CO O) O «*»«t«««kVt«t«k«l*lk.«|«C«h«l lf)lf)lf)cr)if)if)COif)>f)CDCOCOlO*"lf> 8 OOOOOOOOOOOOOO OOOOOOOOOOOOOO COCOCOCOCOCOCOCOCDCOCOCOCOOCO OOOOOOOOOOOOOOO OOOOOOOOOOOOOOO COCOCDvOlf)— COCMTTOCOCOCOlf) — Kt«-0)C\ICDM^-|^(D fflWQO* c\ a CM *• O o o 8 o o CM m •t ON CM CM £ 00 O o o o o o CO in o at A « if) CO I— e> CM CO ™" UJ c- >- O o 8 o o X a. O J>- CO l»- 1- o o CO o CM o o O) o o o o en * o o CM 8 o o CO (ONCOOO-CMO'fcOCer-.COOlO- p)fOP>nv'r<)-^«-'j-fl-<('Tf*cnco i I I i i i I i I i i i I i I i mCOSOOOlO-cMCOflOCOIccocDO cococococo*j-*c)"^-^if'*-*cj-iir« CO 2-61* UJ Ul to ■*• o z o «r if) cu CI O) O) > CD -* — Santa Paula Basin , Santa Paula Basin lies between Fillmore Basin on the east and the Oxnard Forebay and Mound Basins on the west. The surface area of the basin, which for study purposes was defined by the extent of the alluvium, is about 13,520 acres. Surface elevations in the Santa Clara River channel vary from about 280 feet above sea level at the eastern extremity of the basin to about 1^0 feet at the westerly limit. Surface waters drain westerly in the river channel and southerly in Santa Paula Creek, a principal tributary. Y/ater-bearing formations in Santa Paula Basin include Recent and Pleistocene alluvium having a maximum depth of about 200 feet, underlain by the older San Pedro formation which extends to depths as great as 14,000 feet. However, aquifers of the San Pedro formation in Santa Paula Basin are presently utilized to a maximum depth of about 800 feet. The southerly boundary of Santa Paula Basin is defined by the Oak Ridge fault. The Saticoy fault, which is probably either a branch or an extension of the Oak Ridge fault, separates Santa Paula Basin and the Oxnard Forebay Basin. The boundary between Santa Paula and Mound Basins is defined by an abrupt change in slope of the ground water surface, similar to those described between Piru and Fillmore Basins and between Fillmore and Santa Paula Basins. Geologic section G-G 1 on Plate 12-A shows the major geologic features of the basin. Ground water in Santa Paula Basin is generally unconfined, although a localized pressure condition does prevail in the alluvium in the westerly and northwesterly portions of the basin. Ground water generally moves in a southwesterly direction in conformity with the slope of the ground surface. Water wells in the basin draw from both the alluvium and the underlying San Pedro formation, and yield up to 1,^00 gallons per minute, with a probable average yield of about 700 2-65 gallons per minute. The estimated weighted average specific yield of water-bearing materials in the basin, in the range of depth between the highest and lowest historic water levels, is approximately 10 per cent. Ground water storage in the Santa Paula Basin is replenished by subsurface flow and effluent discharge from Fillmore Basin, by per- colation of runoff in the Santa Clara River, Santa Paula Creek, and minor tributary streams, by deep penetration of direct precipitation, and by percolation of the unconsumed portion of water applied for irrigation and other uses. During the period from 1930 to I9I4I, inclu- sive, water from Santa Paula Creek was spread at grounds operated by the Santa Clara Water Conservation District near Santa Paula. This practice was abandoned in 19Ul, however, because of the prevailing high ground water levels. Disposal of ground water in Santa Paula Basin is effected by pumped extractions to meet requirements of irrigated and urban lands overlying and adjacent to the basin, by exportation, by consumptive use of phreatophytes, by subsurface flow and effluent dis- charge to Oxnard Forebay Basin, and by subsurface flow to Mound Basin. Since the net use of ground water in Santa Paula Basin is relatively small in comparison with the magnitude of water supplies available for recharge, historical basin storage depletion has been relatively small. It was estimated that in the fall of 1951 the basin storage had been depleted about 22,600 acre-feet, which is the maximum of record. Examination of Plate 20 shows that over the period of record there was a maximum fluctuation in the water level at key well number 3N/21W-20M1 of only about 35 feet. The relationship between elevations of the ground water surface at this well and ground water storage depletion in Santa Paula Basin is shown on Plate 21. 2-66 Within Santa Paula Basin, measured historical change in ground water levels has been entirely in the alluvium. However, imme- diately to the north of the alluvium defining Santa Paula Basin, the San Pedro formation outcrops on the surface over an area of about 7,900 acres. Since it is indicated that there is hydraulic continuity between the alluvium and the underlying and adjacent San Pedro forma- tion, it is probable that there has been change in ground water storage in the San Pedro formation in the area of outcrop. Lack of well log data and ground water level measurements precluded sufficient determi- nation of physical characteristics of the San Pedro formation adjacent to Santa Paula Basin to estimate change in ground water storage. Based on available data, and for reasons similar to those cited in the cases of Piru and Fillmore Basins, it is believed that utility of Santa Paula Basin is limited by factors of economic pumping lift and mean seasonal recharge, rather than by storage capacity or configuration of the basin. The seasonal results of the monthly hydrologic analysis of Santa Paula Basin are summarized in Table lit. This analysis was made without regard to the undetermined change in ground water storage in the outcrop area of the San Pedro formation north of the basin. The derived values of surface outflow from Santa Paula Basin to Oxnard Forebay Basin, therefore, are in error by the amount of recharge to the San Pedro formation in the outcrop area. In the hydrologic study, items of surface and subsurface flow from Fillmore Basin were taken from the corresponding items of outflow in the analysis for Fillmore Basin presented in Table 13. Additional surface inflow to Santa Paula Basin comprised measured runoff in Santa Paula Creek at the gaging station near Santa Paula, adjusted for upstream diversion. Minor 2-67 tributary surface inflow was estimated by correlation with the measured flow of Hopper Creek. It was assumed that the spreading grounds on Santa Paula Creek did not operate during the period of study. Effluent discharge across the Saticoy fault and into Oxnard Forebay Basin was estimated from the determined correlation between measured rates of discharge and slope of the ground water surface. Subsurface outflow to Oxnard Forebay Basin was estimated by means of the rising water method. As may be noted on Plates ll*-B, 15-B, and 16-B, there is a sharp increase in slope of the ground water surface from Santa Paula Basin to Mound Basin. The slope from Santa Paula Basin to Mound Basin indicates subsurface flow from the former to the latter. Geologic investigation indicates that this underflow occurs in the San Pedro formation. How- ever, the amount of the underflow was not susceptible to evaluation with the data at hand, and the values for subsurface outflow presented in Table Ik include only the underflow to Oxnard Forebay Basin. Hydro- logic and geologic evidence indicates, however, that the unaccounted for subsurface flow may be in the order of 0,000 to 10,000 acre-feet per season. Records were obtained of exports of water to the Oxnard Plain Basin by the Santa Clara Water and Irrigation Company, and to Mound Basin by the Farmers Irrigation Company. The hydrologic study commenced with an assumed basin storage depletion in the fall of 1936 of 22,600 acre-feet, which was the esti- mated actual depletion in the fall of 1951 • It was found that under conditions of the study the basin would have first filled in January, 1937 } and would have filled or nearly filled each spring thereafter through 1950. From the spring of 1950 until the fall of 1951, disposal of water on the basin would have exceeded recharge, and basin storage would have again been depleted in the amount of 22,600 acre-feet by the fall of 1951. 2-68 o o CO ■< CO 3 o z CO •< CD Ui CO «S =) _l =3 O •. Lf> CM — CO r— 1" — — — — — o I I I I I I I I I I 8 Q O O O O o o o o o o 000000 _ OOOOOOO (O -*o) -OOs -nNQCMBS COCD(OO)-.t<)NiONmi/)0lOCMCO cm uo — co — m m- — — — ooooooooooooooo OOOOOOOO OOOOOOO CDCOfCDCMOJOCO o O CO OI s co o> co CMCMCMWCOCMCOCM CO CM CM CM CM CM CM o o 8 o o o o o o o o ooo ooooo _ o o g ooooo_ SOVOCMCOO)* if CO m m CM CO ******** ****** 8 o o •fl- CO ak * CD CD CM CM O o O o f- o> ooooooooooooooo o o CO CO o o o in 8 O O O — o •3" o CD o CD o o CD *r OOO CM — CM to uo to in CO I - UO uo CD ir> r— r»- r^ co i>- OOOOOOOOOOOOOOO OOOOOOOO OOOOOOO CD CD — 00 CM CD - OI l»- O T ■»>- CO r Ocm «f * cm * "r io cm cm in — oo — uo *J- — — — 8888 en co — co OOOOOOOOOOO OOOO OOOOOOO *r — vooin O- O O? — ******** ******* lOOi'OvnmoofiO'tcooKOO) CM CM - _ ^J- _ CO CM — — — — OOOOOOOOOOOOOOO OOOOOO OOOOOOO T — — • ^- *»• uo uo I ! I I I I I I I I I I I I I I IfllON CO O) O - CMCO V If) CO s to cn o concococo*') , «>* *r *r ■*■ *ti vr rt ua 0)00)0)000)0)00) O) O) CD CD CD O) O) 2-69 X X * X (- _l CO CJ> O CO o z X a o =■ r- o * O o — o O IT * cc K 0E (0 E ce O X as o x (X. UJ X UJ => o — H- O O f— O Cu 1— o ■n Li cc u. — Lu =3 > Ui !»• oc f«- ■■3- ►- tf) _< =) UJ Q_ CO LT> uj uj CO T IU x •«- up o -J a 1 1 w a. 1 O CB 1 1 z -1 i UJ CO o < CO CO «t = TI- o MB «r a » CO uo C KCO ■<1- CC CS T UO UJ < cr> m lu iu en Ui cr o) > CO — £*- > O — -* 00 gallons per minute, with an average yield of about 700 gallons per minute. Specific capaci- ties of wells in the basin are estimated to average about 70. Ground water in Mound Basin is replenished by subsurface in- flow from Santa Paula Basin, and by subsurface flow from the outcrop area of the San Pedro formation which receives percolation of direct precipi- tation and stream flow in minor watercourses. Ground water in the basin is disposed of by pumped extractions to meet overlying domestic and ir- rigation requirements, and possibly by subsurface outflow to the ocean. Examination of ground water contour maps indicates that there may also be subsurface inflow to and outflow from Oxnard Plain Basin through the San Pedro formation, depending on the relative ground water levels in the Mound and Oxnard Plain Basins. It also appears from study of Plate 16-B, that during drought periods when piezometric levels in Mound Basin are below sea level, sea water may contribute to the seaward extensions of the pumped aquifers. Water requirements of irrigated lands overlying Mound Basin are satisfied in part by imports of water from Oxnard Forebay Basin by the Alta Mutual Water Company, and from Santa Paula Basin by the Farmers Irrigation Company. The average seasonal amounts of these imports dur- ing the base period were about 2,100 acre-feet and 600 acre-feet, respec- tively. 2-71 Uncertainties regarding hydrologic and geologic characteris- tics precluded direct evaluation of all items of water supply of Mound Basin and disposal thereof during the base period. It is believed, however, that the primary recharge of the basin is by subsurface inflow through the San Pedro formation from Santa Paula Basin, and that the contribution from the outcrop of the San Pedro formation to the north of the basin is of secondary magnitude. The average seasonal extrac- tion of ground water from Mound Basin during the drought period, from 19l4i-US> through 1950-51* was estimated to have been about 13*500 acre- feet. This includes extractions by the City of Ventura during the seasons of 19U7-U8, 19U8-U9, 19ii9-50, and 1950-51, of about 1,730 acre- feet, 3,2ltO acre- feet, 2,200 acre-feet, and ii,000 acre-feet, respec- tively, together with an estimated average extraction of 600 acre-feet per season from the westerly extremity of the basin. Fluctuations of ground water levels in key well number 2N/22W-8N1 during the period from 1928 through 1952 are shown on Plate 20. It may be noted on the hydrograph that the piezometric level in this well was below sea level from the spring of 1929 to the fall of 1931, and from the spring of 1950 until the fall of 1951, and was also drawn down slightly below sea level for a short period in the spring of 19^8. During the wet season of 1951-52 the piezometric level recovered to approximately 18 feet above sea level. Examination of lines of equal elevation of ground water in Mound Basin for the fall of 1951, as shown on Plate 16-B, indicates the presence of a depression in the piezometric surface near the coastal front. The center of this depression was about 16 feet below sea level. It is probable that this depression was formed as a result of heavy pumping from the beach wells of the City of Ventura, and as a result of pumping from the con- 2-72 centration of irrigation wells of heavy draft in this vicinity. For- mation of this dep ression lends evidence to a conclusion that the rate of pumping draft exceeded the transmissibility of aquifers extending from Santa Paula Basin, from which subsurface flow appears to be the principal source of ground water supply for Mound Basin. It is probable that during periods when a depression in the piezometric surface pre- vailed, a portion of the water supply to Mound Basin was obtained from the seaward extension of the aquifers. However, it is believed that sea water intrusion to the wells in the vicinity of the depression did not occur since no increase in chloride concentration in water extracted from the wells was noted. Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins . Con- fined aquifers of economic significance in both the Oxnard Plain and Pleasant Valley Basins receive a large portion of their water supply from unconfined ground water in Oxnard Forebay Basin, which in turn is princi- pally replenished by water of the Santa Clara River. Because of the hydraulic continuity between the three basins, they are discussed to- gether in this section. Their relative locations are shown on Plate 11. The three basins comprise a total area of about 76,i|80 acres, of which Oxnard Forebay Basin occupies about 6,170 acres, Oxnard Plain Basin about i|6,U60 acres, and Pleasant Valley Basin about 23,850 acres. Ground sur- face elevations vary from about 60 feet to 150 feet above sea level in Oxnard Plain Basin, and from about 15 feet to 21*0 feet in Pleasant Valley Basin. Surface waters course westerly and south-westerly to the ocean in the Santa Clara River, Calleguas Creek, and several minor streams and artificial drainage channels. Water-bearing formations in the three basins consist princi- 2-73 pally of alluvium of Recent and Upper Pleistocene age, and of the under- lying San Pedro formation of Lower Pleistocene age. In Oxnard Forebay Basin the aquifers primarily utilized are sands and gravels of the Recent and Upper Pleistocene alluvium. In Oxnard Plain Basin, the prin- cipal aquifer is a zone of sand and gravel lenses in the Upper Pleisto- cene alluvial deposits. This zone has been designated and will herein- after be referred to as the "Oxnard aquifer". A second aquifer, the Fox Canyon member of the San Pedro formation is in contact with the base of the alluvium in Oxnard Forebay Basin, and underlies but is probably hy- draulically separated from the alluvium in the Oxnard Plain and Pleasant Valley Basins. This aquifer is utilized only to a minor extent in the Oxnard Forebay and Oxnard Plain Basins, but supplies most of the water to users in Pleasant Valley Basin. In Pleasant Valley Basin, ground water is also obtained from sand and gravel lenses in Recent and Upper Pleis- tocene deposits which do not appear to be connected with the Oxnard aqui- fer, and to a minor extent from aquifers in the Santa Barbara formation underlying the Fox Canyon aquifer and from fractures and fissures in vol- canic rocks along the southeasterly portion of the basin. Well log sec- tions K-K', L-L', and M-M' on Plate 12-B show the structures and relative position of the water-bearing formations and aquifers in the three basins. Depths from ground surface to the bases of these aquifers are shown in Table 11, together with estimated thicknesses thereof. The boundary of Oxnard Forebay Basin was taken at the Saticoy fault and the Santa Clara River on the north, and around the remainder of the basin's periphery at the limit of the area of unconfined ground water. Oxnard Plain Basin was defined by the boundaries of the Oxnard Forebay and Mound Basins on the north, by that of West Las Posas Basin in the 2-74 Calleguas-Conejo Hydrologic Unit on the northeast, and by that of Pleasant Valley Basin on the east and southeast. The basin is bounded by the ocean on the west, but the Oxnard aquifer probably extends beneath the ocean. The boundary oetween Oxnard Plain and the Pleasant Valley and West Las Posas Basins corresponds to the assumed limit of lands underlain by the Oxnard aquifer. The boundaries of Pleasant Valley Basin on the north, east, and south were taken as the limit of the alluvium. The northeasterly boundary was defined by topographic features. The Oxnard aquifer of Oxnard Plain Basin is overlain by sedi- ments of low permeability, which separate this economically important aquifer from a semi-perched ground water body of inferior mineral quality in the alluvium near the ground surface. The relatively imper- meable sediments result in confinement of water in the Oxnard aquifer. Whether or not there is complete severance of hydraulic continuity between the semi-perched ground water and water in the Oxnard aquifer was not firmly established. The portions of the Fox Canyon aquifer in both the Oxnard Plain and Pleasant Valley Basins, and aquifers of the Santa Barbara for- mation in Pleasant Valley Basin, are also confined by sediments of low permeability. As shown on Section K-K' on Plate 12-B, both the Oxnard and Fox Canyon aquifers appear to extend off-shore beneath the capping and relatively impermeable sediments. Absolute geologic evidence that these aquifers are exposed to the ocean is not available. However, off- shore soundings indicate the existence of two submarine canyons incised in the ocean floor, near Port Hueneme and near Point Mugu. These canyons are of sufficient depth to indicate the probability of exposure of the 2-75 Oxnard aquifer to the ocean at points as close as one-quarter mile from the coastline. Although there are not sufficient off-shore data to establish the probability of outcrop of the Fox Canyon aquifer in the submarine canyon near Port Hueneme, it appears probable that this aquifer does outcrop in the submarine canyon near Point Mugu. As described here- inafter in this chapter under "Quality of Water", the intrusion of sea water to wells pumping from the Oxnard aquifer in the vicinity of Port Hueneme has been fairly well established. Ground water occurring in Oxnard Forebay Basin is unconfined, and it is indicated that it moves from the basin under pressure in a southwesterly direction through the Oxnard aquifer to areas of pumping draft in Oxnard Plain Basin. It is also indicated that ground water leaves Oxnard Forebay Basin under pressure and moves in a southerly direction through the Fox Canyon aquifer to Pleasant Valley Basin. The directions of movement of ground water from Oxnard Forebay Basin are shown on Plates llj-B, 15-B, and 16-B. It was observed that during the recent drought period, troughs or depressions were formed in the piezo- metric surfaces of the Oxnard aquifer in Oxnard Plain Basin, and of the Fox Canyon aquifer in Pleasant Valley Basin. The positions and depths of the troughs varied in accordance with pumping draft from the two aquifers, and with elevation of the ground water surface in Oxnard Fore- bay Basin. As a result of formation of the troughs, the direction of ground water movement on their seaward sides was reversed, as shown on Plate 16-B. Plate 13, entitled "Diagrammatic Sketch of Oxnard Forebay and Oxnard Plain Basins" shows the relative position of the peizometric surface in the Oxnard aquifer in Oxnard Plain Basin in spring of 19hh and in the fall of 1951? indicating direction of ground water movement 2-76 therein under two extreme conditions. Wells drawing from Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins yield on the average from 900 to 1,100 gallons of water per minute. However, wells drawing on the alluvium in Pleasant Valley yield an average of about 1*00 gallons per minute. Specific capacity of wells in Oxnard Forebay Basin averages in excess of 200, in Oxnard Plain Basin about 75* and in Pleasant Valley Basin about 1|0. The estimated weighted average specific yield of water-bearing materials in Oxnard Forebay Basin, in the range of depth between the highest and lowest his- toric water levels, is approximately 16 per cent. Ground water storage in Oxnard Forebay Basin is replenished by natural percolation of surface flow in the Santa Clara River, and by per- colation of Santa Clara River water which is diverted to the spreading grounds now operated by the United Water Conservation District near Saticoy. Ground water storage in the basin is also replenished by sub.* surface inflow from Santa Paula Basin, deep penetration of direct preci- pitation, and percolation of the unconsumed portion of water applied for irrigation and other uses. Ground water in Oxnard Forebay Basin is dis- posed of by pumped extractions for beneficial consumptive uses of over- lying lands, by exportation, by consumptive use of phreatophytes, and by subsurface outflow to the Oxnard Plain and pleasant Valley Basins. As has been stated, the Oxnard aquifer of Oxnard Plain Basin is supplied principally by subsurface inflow from Oxnard Forebay Basin. To a lesser degree it receives underflow from West Las Posas Basin. During the recent drought period, when the hydraulic gradient in the Oxnard aquifer on the seaward side of the cited trough was reversed, contribu- tion to the aquifer appears to have been obtained from the ocean. Also, 2-77 there may be some exchange of water between the Oxnard and Fox Canyon aquifers in Oxnard Plain Basin, and between the Oxnard aquifer and the overlying semi -perched ground water body. Disposal of ground water in Oxnard Plain Basin is effected by pumped extractions for beneficial uses, by subsurface outflow to the ocean during periods of high peizometric level in the aquifers, and to a minor extent, by effluent discharge through uncapped wells during periods of high piezometric level. Aquifers in Pleasant Valley Basin are supplied primarily by subsurface inflow from adjacent basins. Such contributions are received through the Fox Canyon aquifer from Oxnard Forebay Basin, and from East Las Posas and Santa Rosa Basins in the Calleguas-Conejo Hydrologic Unit. They are also received from fractured volcanic rocks on the southeast side of the basin. Some replenishment may be received as subsurface in- flow from West Las Posas Basin through the Fox Canyon aquifer which crosses beneath the Camarillo Hills. As in the case of the Oxnard aquifer, with the formation of a trough in the piezometric surface in the Fox Canyon aquifer in Pleasant Valley Basin during the recent drought period, it appears that there may have been subsurface inflow through this aquifer from the ocean. Ground water found in the little-used aquifers of the alluvium in Pleasant Valley Basin appears to be replenished principally by subsurface inflow from adjacent hill areas. Disposal of ground water in Pleasant Valley Basin is effected by pumped extractions for beneficial uses, probably by subsurface outflow to the ocean during periods of high piezometric level in the aquifers, and to a minor extent by effluent discharge through uncapped wells during periods of high piezometric level. It has been stated that during the recent drought period, with 2-78 an increase in ground water extractions and a general diminution of water supplies accompanied by lowered ground water levels in Oxnard Forebay, troughs formed in the piezometric surfaces in both the Oxnard aquifer in Oxnard Plain Basin, and in the Fox Canyon aquifer in Pleasant Valley Basin. In the Oxnard aquifer the trough first appeared in the spring of 19i;6, at a location about 3 miles inland from the coastline and south- east of the City of Oxnard. This trough subsequently disappeared, but reappeared during the seasons of 19li7-U8 and 19U8-1# during times of heavy pumping draft. Subsequent to the spring of 19h9 the trough persisted, with its center substantially below sea level, until the wet season of 1951-52. As ground water levels continued to lower in Oxnard Forebay, and with continuation of heavy pumping draft from the Oxnard aquifer, the trough also deepened and moved inland until in the spring of 1951 its center was from five to six miles from the coastline and about UO feet below sea level. At that time, in excess of 27,000 acres of land were being supplied with water pumped from the seaward side of the trough, wherein conditions were conducive to the intrusion of sea water. It was estimated that during the seasons of 19U9-50 and 1950-51 about 25,500 and 31,800 acre-feet of water, respectively, were extracted from Oxnard Plain Basin from the seaward side of the trough. In excess of 90 per cent of these amounts were extracted from the Oxnard aquifer, with the remainder from the underlying Fox Canyon aquifer through wells perforated in both aquifers. Since the position and depth of the trough varied considerably prior to the spring of 1950, it was not feasible to evaluate ground water extractions on the seaward side of the trough before that time. Fluctuations of piezometric levels in the Oxnard aquifer at 2-79 wells numbers 1N/22W-7D1, 1N/21W-19A1, and 1N/22W-3F1* are shown on Plate 20. A composite hydrograph of water levels at wells numbers 2N/22W-23KL, 2N/22W-23H2, and 2N/22W-23H3, representative of fluctua- tions in the ground water surface in Oxnard Forebay Basin, is also shown on Plate 20. It may be noted from this hydrograph that ground water levels in Oxnard Forebay Basin were below sea level for a short period in 1951 • The relationship between dewatered ground water stor- age capacity in Oxnard Forebay Basin and elevation of the ground water surface at well number 2N/22W-23H3 is shown on Plate 21. With the present pattern of pumping, the utility of Oxnard Forebay Basin appears to be limited by its probable hydraulic continuity with the ocean through the Oxnard aquifer in Oxnard Plain Basin. In order to maintain a seaward gradient in the piezometric surface in the Oxnard aquifer with minimum pumping draft therefrom, it was estimated that ground water storage depletion in Oxnard Forebay Basin must not exceed 87,000 acre-feet. As shown on Plate 21, elevation of key well number 2N/22W-23H3 would be about 12 feet above sea level with this estimated maximum safe ground water storage depletion. The trough in the piezometric surface of the Fox Canyon aquifer underlying Pleasant Valley first formed during the drought period in the spring of 19l|6. By the fall of 19U6 its center was more than 10 feet below sea level. The trough disappeared during the winter of 191*6-1*7, but again appeared in the spring of 191*7, with its center approaching 20 feet below sea level in the fall of that year. After recovering during the winter of 191*7-1*8, the trough again formed in the spring of 191*8, and has persisted until 1953- The maximum depth of the center of the trough below sea level was estimated to have been about 60 feet in August of 1951. The center of the trough, as shown on 2-80 Plate 16-B, occurred about four miles southwest of the town of Camarillo. Fluctuations of the piezometric surface in the Fox Canyon aquifer at well number 1N/21W-16A1, which is near the center of the trough, are shown on Plate 20. Also shown on Plate 20 are fluctuations of the piezometric surface in the Fox Canyon aquifer at well number 2N/20W-17J3, which is in the northeasterly portion of the basin near Somis. It may be noted that since the time of first measurement in 1920, the water surface elevation at well number 2M/20W-17J3 has shown a rather persistent decline. It is believed that this is indicative of the perennial lowering of ground water levels in the Fox Canyon aquifer in East Las Posas Basin, which occurrence is described hereinafter in this section. Uncertainties regarding the exact position of the trough in the Fox Canyon aquifer in Pleasant Valley Basin, and inadequate data concerning amounts of water extracted from the several other aquifers supplying overlying lands in the basin, precluded evaluation of the magnitude of extractions from the Fox Canyon aquifer from the seaward side of the trough. Plates 1U-B, 15-B, and 16-B depict the elevation of the ground water surface in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins in the fall of 1936, in the spring of 19liU, and in the fall of 1951* respectively. Plate 15-B also shows the approximate extent of the area wherein piezometric levels in the pressure aquifers were above ground surface in the spring of 19U*. Delineated on Plate 16-B is the area where piezometric levels were below sea level in the fall of 195l> and underlain by a landward gradient in the piezometric surface, which condition was conducive to intrusion of sea water to the aquifers. The estimated maximum areal extent of lands in the vicinity of Port Hueneme actually underlain by sea water is also delineated on Plate 16-B. A monthly analysis was made of water supply and disposal in 2-81 the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins during the base period, with present conditions of land use and pattern of pumping. In commencing this analysis, it was assumed that ground water storage depletion in Oxnard Forebay Basin in the fall of 1936 was equal to that in the fall of 1951 j or about 109*500 acre-feet. Items of water supply to Oxnard Forebay Basin included surface and subsurface outflow from Santa Paula Basin, as shown in Table lk» In addition, a portion of the export of water from Santa Paula Basin, shown in Table ll*, was delivered to Oxnard Forebay and Oxnard Plain Basins by the Santa Clara Water and Irrigating Company. An additional source of water supply to Oxnard Plain Basin consisted of underflow from West Las Posas Basin, estimated to have averaged about 600 acre-feet per season. Underflow to Pleasant Valley Basin, principally through the Fox Canyon aquifer from Santa Rosa and East and West Las Posas Basins, and to a lesser extent from fractured volcanic rocks on the southwest side of this basin, constituted an esti- mated average seasonal supply of about 14,100 acre-feet. Records were ob- tained of diversions to the Saticoy spreading grounds. Exports of water from Oxnard Forebay Basin to Mound Basin in an average seasonal amount of about 2,100 acre-feet by the Alta Mutual Water Company, and of export of water to West Las Posas Basin from Oxnard Plain Basin by the Del Norte Water Company in an average seasonal amount of about 1,100 acre-feet, were determined from records of these two companies. For purposes of analysis it was assumed that hydraulic continuity does not exist between the confined aquifers in Oxnard Plain' and Pleasant Valley Basins and overly- ing media. Estimates of extractions of water from these confined aquifers were made for the period from 19hh-k$ through 1951-52. The estimated seasonal extractions that would have been made during the wet period in 2-82 the Oxnard Plain and Pleasant Valley Basins, under present conditions of land use and water supply development, were taken as the average of deter- mined extractions during the two seasons of 19UU-U5 and 1951-52. Sub- surface outflow to the ocean through the Oxnard aquifer was estimated from parameters derived from correlation of ground water surface elevations in Oxnard Forebay Basin, and slopes of the piezometric surface and rates of flow in the Oxnard aquifer. It was estimated that with Oxnard Forebay Basin essentially full, subsurface outflow to the ocean in the aquifer would have a maximum rate of about 2,000 acre-feet per month. It was further estimated that the rate of subsurface outflow with the present pattern of pumping and with Oxnard Forebay Basin essentially full would not be materially affected until the rate of pumping draft from Oxnard Plain Basin exceeded lj.,300 acre-feet per month. With lowering of ground water levels in Oxnard Forebay Basin and a rate of pumping draft from Oxnard Plain Basin in excess of lj,300 acre-feet per month, it was estimated that the rate of subsurface outflow to the ocean through the Oxnard aquifer would be reduced. The reasonableness of these estimates were substantiated by independent determinations using the slope area method. The seasonal summary of the monthly hydrologic analysis of the three basins is presented in Table 15. It may be noted from the table that in order to effect hydrologic balance in most seasons, an item of supply designated "undifferentiated supply from other sources" is shown. For seasons prior to 1°IjU-U5j the amount of this supply was determined as a differential in solution of the equation of hydrologic equilibrium under estimated historical rather than study conditions. It was then assumed that the derived magnitude of this supply would not have been materially 2-83 different under the assumed conditions of the study. For seasons subse- quent to the fall of 1944, at which time Oxnard Forebay Basin was filled, both historically and under study conditions, it was assumed that changes in ground water storage in that basin would have occurred under study conditions as they did historically. The undifferentiated supply from other sources was then evaluated as a differential in solution of the equation of hydrologic equilibrium under these assumed conditions. There are four water sources which probably contribute to the aforementioned "undifferentiated supply from other sources", but from data at hand it was not possible to evaluate the magnitude of the supply from each source: (1) Contribution to the pumped aquifers of Pleasant Valley Basin may occur from perennial change in storage in free ground water areas in adjacent hills, which ground water bodies are believed to be hydraulically connected with the aquifers in the basin.. Change in ground water storage in these areas could not be evaluated because of the lack of well log and water level control. (2) During drought periods, and other times of heavy pumping draft, with attendant lowering of piezometric levels and relief in hydraulic pressure in aquifers underlying the Oxnard Plain and Pleasant Valley Basins, it is possible that clays and other relatively impermeable sediments overlying these aquifers could be com- pacted. Such compaction would result in release of water from the clays and sediments to the underlying aquifers. It is believed that any pos- sible contribution to the water supply from this source is of small mag- nitude. (3) It was assumed that the principal pumped aquifers in the Oxnard Plain and Pleasant Valley Basins are not hydraulically connected with overlying semi-perched ground water bodies. The presence of extensive beds of clay and other materials of low permeability between 2-84 the pumped aquifers and the semi-perched water bodies has been assumed to preclude supply to the pumped aquifers of water applied to the ground surface, direct precipitation, and other surface waters. .including the semi-perched water. It is conceivable, however, that these separating clay beds are not continuous, and that the pumped aquifers do in fact receive some recharge from overlying waters. It is possible that water supply from this source could be substantial. (4) As described previously, it was estimated that during the seasons of 1949-50 and 1950-51, water in the amounts of 25,500 acre- feet and 31*800 acre-feet, respectively, was pumped in Oxnard Plain Basin, largely from the Oxnard aquifer on the sea- ward side of the trough. The volume of these extractions was probably replaced by an equal volume of sea water in the seaward extension of the Oxnard aquifer. 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Water-bearing materials in Simi Basin consist of alluvial gravels, sands, and clays of Recent and Pleistocene age, having a maximum depth of about 700 feet. The alluvium is underlain and bounded by older consolidated sediments, wherein ground water is found in minor amounts in fractured zones and in permeable lenses of sands and gravels. The base of the alluvium is concave in shape, deepening toward the center from the peripheral margin. Geologic cross sections Q-Q' and R-R' on Plate 12-C depict the structure and shape of the basin. Ground water in the alluvium is generally unconfined, although clay lenses, particularly in the wester- ly extremity of the basin, cause localized pressure conditions in the ground water body. Wells in the westerly portion of the basin have been known to flow during periods of high ground water. Normally, ground water moves in a westerly direction toward East Las Posas Basin, as shown on Plates lU-C and 15-C. However, during periods of heavy pumping draft and lowered ground water levels, the slope of the ground water surface at the westerly end of the basin is reversed, as shown on Plate 16-C. Ground water storage in Simi Basin is replenished by percola- tion of direct precipitation, of the flow of minor streams, and of the unconsumed portion of water applied for irrigation and other uses, and to a limited extent by lateral subsurface inflow from the flanking consolida- ted formations. Water is imported to the basin by the Tapo Mutual Water 2-90 Company from a well field in Tapo Canyon. These wells pump from aquifers in the Santa Barbara formation, which formation is not hydraulically con- nected to the alluvium in Simi Basin, although surface waters in Tapo Canyon are tributary to the basin. Some recharge to the basin has been effected through minor spreading operations. Runkle Reservoir, with a storage capacity of 100 acre-feet, located on a minor watercourse on the south side of Simi Valley, is utilized for flood control and to regulate releases to spreading grounds downstream from the dam. In general it is believed that spreading operations in Simi Basin have not contributed significantly to ground water replenishment. Ground water in Simi Basin is disposed of by pumped extractions for use on overlying lands and on lands adjacent to the basin, by con- sumptive use of phreatophytes, and by effluent discharge and subsurface outflow to East Las Posas Basin. Wells in the basin are estimated to have an average yield of about 400 gallons per minute. Wells drawing from the older formations around the perimeter of the basin, and from the Santa Barbara formation in Tapo Canyon, are estimated to yield an average of about 100 gallons per minute. The ground water storage capacity of Simi Basin was estimated to be approximately 180,000 acre- feet. In the fall of 1951, estimated ground water storage depletion in the basin was about 31,000 acre-feet, the greatest during the period for which records of ground levels are available. Ground water levels in Simi Basin have exhibited substantial lowering since measurements were first recorded in the late 1920' s. As shown by the hydrograph of the water level in key well number 2N/18W-12L3, on Plate 20, ground water levels showed a persistent decline from 1929 to 2-91 19U1, when in an excessively wet season there was a substantial recovery. Water levels in the basin were then essentially stabilized until 19U*-!i5> when a rapid decline again commenced which persisted through 1951-52. The relationship between elevation of the ground water surface at well number 2N/18W-12L3 and ground water storage depletion in Simi Basin is shown on Plate 21. The total decrement in ground water storage during the base period was estimated to have been about 21,000 acre-feet, or an average of about 1,1*00 acre-feet per season. Tributary surface inflow during the period averaged an estimated 5,300 acre-feet per season, including an average import of about 1,1*00 acre-feet per season by the Tapo Mutual Water Company. Surface outflow, as measured at the gaging station on Arroyo Simi near Simi, averaged 1,100 acre-feet per season during the base period. Subsurface outflow to East Las Posas Basin was estimated by the slope-area method to have been about 100 acre-feet per season. Direct seasonal precipitation on the ground water basin was estimated to have averaged about 13,300 acre-feet. Average seasonal consumptive use of water on lands overlying the ground water basin, and seasonal consump- tive use of water from the basin applied on water service areas adjacent to the basin was estimated to have totaled about 18,800 acre-feet. Of this amount, about 7,500 acre-feet per season represents consumptive use of applied water. It should be pointed out that, as described in Chap- ter III, analysis of records of application of water to principal crops grown in Simi Basin indicate that in certain portions of the basin these crops have subsisted on deficient water supplies. Had adequate applica- tions of water been given to these crops, the foregoing estimated average seasonal consumptive use of applied water of 7,500 acre-feet would have 2-92 been increased to an estimated 9*700 acre-feet. East and West Las Posas Basins . The East and West Las Posas Basins, situated in the northerly portion of the Calleguas-Conejo Hydro- logic Unit and west of Simi Basin, have a surface area of about ii?,820 acres. Elevation of the basins varies from about 200 feet to more than 1,500 feet above sea level. East Las Posas Basin is drained by Arroyo Las Posas, which passes southwesterly into Pleasant Valley Basin in the vicinity of Somis. Surface runoff in West Las Posas Basin drains westerly through several minor watercourses to Oxnard Plain Basin. Ground water in East and West Las Posas Basins occurs in Recent and Pleistocene alluvial deposits, and in the San Pedro and Santa Barbara formations. These latter two formations have been folded into east-west trending synclines and anticlines, Alluvium containing ground water in usable quantities comprises an area of about 5A00 acres on the south side of East Las Posas Basin, extending to depths of about 200 feet. Alluvial deposits elsewhere in the two basins are generally of relatively shallow depth, or so high in silt and clay content that little water is yielded to wells. Ground water in the alluvial deposits is generally unconfined. The principal pumping aquifer in the San Pedro formation is the Fox Canyon member. The Epworth gravels, occurring near the upper limits of the San Pedro formation, comprise a secondary aquifer in this formation. Ground water in usable quantities is obtained from the Grimes Canyon member of the Santa Barbara formation, which underlies the aforementioned San Pedro formation. Sections L-L' and N-N 1 on Plates 12-B and 12-C show the structure and relative position of the alluvial deposits and the Fox Canyon and Grimes Canyon aquifers. Section P-P' on Plate 12-C 2-93 shows the structure and relative position of the foregoing aquifers, together with the Epworth gravels. Ground water found in the Fox Canyon and Grimes Canyon aquifers is confined, except near their outcrop areas. Ground water in the Epworth gravels is generally unconfined. The Fox Canyon aquifer underlies both East and West Las Posas Basins. From analy- ses of limited subsurface geologic data, it is believed that the Grimes Canyon aquifer underlies much of the area of the two basins. It is also believed that the Fox Canyon and Grimes Canyon aquifers are interconnected over most of East Las Posas Basin. The alluvium and the Epworth gravels are isolated from each other, and from the Fox Canyon and Grimes Canyon aquifers, by sediments of low permeability. Ground water extractions for beneficial use are primarily from the alluvium and the Fox Canyon aquifer in East Las Posas Basin, and almost entirely from the Fox Canyon aquifer in West Las Posas Basin. The alluvium in East Las Posas Basin is recharged primarily by percolation of flow in Arroyo Las Posas, by percolation of the unconsumed portion of water applied for irrigation and other uses, and by deep pene- tration of direct precipitation. The Epworth gravels and Fox Canyon and Grimes Canyon aquifers are recharged largely by deep penetration of direct precipitation on outcrop areas, and by percolation of flow in minor streams traversing these outcrops. Ground water in the Epworth gravels and in the Fox Canyon and Grimes Canyon aquifers is disposed of through pumped extractions to meet consumptive uses of overlying lands and through consumptive use of phrea- tophytes. Subsurface outflow to the Oxnard Plain and Pleasant Valley Basins constitutes another item of disposal of ground water of the Fox Canyon aquifer. Ground water in the alluvium is similarly disposed of, as 2-9U well as by effluent discharge near Somis, where rising water flows into Pleasant Valley Basin. A portion of the unconsumed residuum of water extracted from the Grimes Canyon and Fox Canyon aquifers returns to ground water storage in the overlying alluvium. As mentioned previously, the alluvium presently exploited by pumping in East Las Posas Basin comprises a surface area of about 5*100 acres. The areas of outcrop of the Fox Canyon aquifer in East and West Las Posas Basins, located along the north side of both basins and the south side of East Las Posas Basin, were estimated to total about 3*320 acres. The Epworth gravels have an outcrop area of about 1,080 acres located along the northerly side of East Las Posas Basin. The Grimes Can- yon aquifer outcrops on both the north and south slopes of Oak Ridge with the estimated area of outcrop being about 5*220 acres. The lack of ade- quate data on subsurface geology precluded evaluation of the magnitude of storage capacity available in either the alluvium or in the underlying older formations. Similarly, it was not possible to evaluate directly the items of water supply and disposal thereof in the two basins. As shown on Plate 20, ground water levels at key well number 2N/20W-1QR1, which is perforated in the Fox Canyon aquifer in East Las Posas Basin, indicate a rather persistent decline from January, 1928 when the well was first measured, until the present time. Although the rate of decline decreased during the wet period, the dry seasons from 1944-45 through 1950-51 accelerated the decline. During the 25-year period of measurement, water levels at this well were lowered approximately 230 feet. Measurements at key well number 2N/21W-16R1, also shown on Plate 20, perforated in the Fox Canyon aquifer in West Las Posas Basin, indicate that the water level lowered about 55 feet during the period from 1927 to 2-95 1953. Some recovery was noted in the water level in this well during the wet period. Subsequent to 1946-47, however, water levels rapidly declined. As shown on Plate 20, ground water levels at key well number 3N/19W-29F3, which is perforated in the Epworth gravels, persistently declined from 1929, but with a more moderate rate than indicated for the Fox Canyon aquifer. Available well measurements indicate that water levels in the alluvium are quickly drawn down during periods of drought, and that they recover rather rapidly during wet periods. The average decrement in ground water storage in East and West Las Posas Basins during the base period was estimated from rather sparse water level and well log control to have been about 5, 000 acre-feet per season. This change in storage occurred primarily in the Fox Canyon aquifer, which is believed to supply most of the water used in the two basins. During this period, seasonal consumptive use of applied water was estimated to have averaged about 16,900 acre- feet. A portion of this consumptive use was met by an import from Oxnard Forebay Basin by the Del Norte Water Company in the amount of about 1,100 acre- feet per season. Subsurface outflow from East Las Posas Basin to Pleasant Valley Basin was estimated by the slope-area method to have been about 3,000 acre-feet per season during the base period. Similarly, it was estimated that about 600 acre-feet per season were discharged to Oxnard Plain Basin as sub- surface outflow from West Las Posas Basin. Cone.jo Basin . Conejo Basin, situated in the south-central por- tion of the Calleguas-Conejo Hydrologic Unit, has a surface area of about 28,930 acres, and its boundaries conform to those of the Cone jo Hydrologic Subunit. Surface elevations vary from about 300 to 2,300 feet above sea level. Surface waters drain primarily in a westerly direction in Cone jo Creek and into Santa Rosa Basin, 2-96 The water bearing materials of Conejo Basin include volcanic rocks of hiocene age, and sedimentary formations ranging from Cretaceous to Recent in age. The volcanic rocks are weathered and fractured, with the degree of fracturing being greater in some areas than others. All formations except the alluvium are folded and faulted. In general, the alluvium is quite shallow, and ground water in usable quantities occurs primarily in fissures and weathered zones in the volcanic rocks. Some ground water is also found in permeable lenses of sandstones and conglome- rates in the Topanga and Modelo formations of Miocene age. Ground water is essentially unconfined, and its movement conforms to the surface slope. Ground water storage in Conejo Basin is replenished by deep penetration of direct precipitation, by percolation of flow in Conejo Creek and its tributaries, and by percolation of the unconsumed portion of water applied for irrigation and other uses. Ground water is disposed of through pumped extractions to meet requirements of overlying lands, by subsurface outflow to Santa Rosa Basin through the volcanics, by effluent discharge into Santa Rosa Basin, and by consumptive use of phreatophytes. There may also be some direct contribution to the supply of Pleasant Valley Basin by subsurface outflow from Conejo Basin through the volcanic rocks. Because of the irregular pattern of the fracture system, yield of wells in Conejo Basin varies over wide limits. Those wells penetrating large fractures or fissures have been known to yield as much as 1,000 gallons per minute. This, however, is the exception, with the general yield averaging on the order of 50 gallons per minute. The indeterminate irregularities in the fracture systems found in the volcanic rocks precluded evaluation of total storage capacity in Conejo Basin through use of conventional methods. Furthermore, since only 2-97 one well was measured sporadically in the basin over the base period, it was not possible to estimate change in ground water storage. Indications are that ground water levels in Cone jo Basin recover quite rapidly during wet periods, and that the present use of ground water from the basin is being met by natural replenishment. It was estimated that seasonal con- sumptive use of applied water during the base period averaged about 2,600 acre-feet. Of this amount, about 2,300 acre-feet per season were utilized on irrigated lands. Tierra Rejada Basin . Tierra Rejada Basin, situated north of Cone jo Basin and east of Santa Rosa Basin, has a surface area of about a, 390 acres. The boundaries of the ground water basin are the same as those of the hydrologic subunit of the same name. Surface elevations vary from about 600 feet to 1,600 feet above sea level. Surface waters drain to the west to Santa Rosa Basin. Ground water in Tierra Rejada Basin, as in Conejo Basin, occurs primarily in fissures and fractures of prevailing volcanic rocks of Miocene age. Small areas of the basin on the north and south sides consist of Tertiary formations in which no wells have been drilled. The volcanics extend to depths of about 2,000 feet, and are folded into a westward plunging syncline. Ground water found in the volcanic rocks is generally unconfined, and moves in a westerly direction in conformity with the surface slope. A north-south trending fault near the westerly extremity of the basin results in a differential in water levels across the fault of up to 80 feet. Wells in Tierra Rejada Basin are reported to yield an average of about 300 gallons of water per minute. However, in the periphery of the basin, difficulty has been encountered in obtaining wells of adequate yield. 2-98 Ground water storage in Tierra Rejada Basin is replenished by- deep penetration of direct precipitation, by percolation of flow in minor watercourses, and by percolation of the unconsumed portion of water applied for irrigation and other uses. Disposal of g round water occurs through pumped extractions to meet consumptive use of overlying irriga- tion developments, and probably through subsurface outflow across the aforementioned fault to Santa Rosa Basin. About $00 acre-feet of water per season are exported to Santa Rosa Basin from a well in the extreme westerly portion of Tierra Rejada Basin. It is probable that in the past, depletion of ground water storage in the basin has occurred through effluent discharge and consumptive use of phreatophytes at its westerly extremity. Water level measurements in Tierra Rejada Basin were initiated at the end of the year 19u5 by the Ventura County Water Survey. Since that time ground water levels have shown a progressive decline, and measurements indicate that there was little recovery during the wet season of 1951-52. Water level fluctuations in the basin are illustrated by the hydrograph of well number 2N/l9W-liiDl, shown on Plate 20. Scattered ground water level measurements since 1930 indicate that disposal of ground water from the basin has probably exceeded replenishment thereto. There were, however, insufficient data available to reliably estimate change in ground water storage over the base period. Consumptive use of applied water in the basin during the base period was estimated to have been approximately 500 acre-feet per season. Santa Rosa Basin . Santa Rosa Basin occupies an area of about 3,h90 acres in the central portion of the Calleguas-Conejo Hydrologic Unit, and south of East Las Posas Basin. Surface elevations vary from about 2-99 200 feet to more than uOO feet above sea level. The surface drainage is to the west. Cone jo Creek passes through the westerly portion of the basin and flows to a confluence with Calleguas Creek in Pleasant Valley- Basin. Santa Rosa Basin is comprised of alluvial deposits on the south side, with the San Pedro formation outcropping along the north side. Both of these formations are underlain by fractured volcanic rocks. The alluvium extends to depths of about 200 feet. The San Pedro formation consists of up to 700 feet of gravels, sands, silts, and clays, and is folded into a syncline as shown on Sections N-N 1 and P-P' of Plate 12-C. Ground water occurs in sands and gravels of the alluvium, and in the Fox Canyon aquifer of the San Pedro formation, which aquifer can only be traced in the western portion of the basin. Some ground water is also found in liirited gravels in the silty portion of the San Pedro formation, as well as in fractures of the volcanic rocks. Ground water in the al- luvium, although generally unconfined, does exhibit localized pressure conditions. Ground water in the Fox Canyon aquifer, and in other gravels of the San Pedro formation, is confined except in the outcrop areas. Ground water moves generally to the west toward Pleasant Valley Basin. Ground water storage in the alluvium of Santa Rosa Basin is replenished by percolation of flow in Conejo Creek and its tributaries, by deep penetration of direct precipitation, by percolation of the unconsumed portion of water applied for irrigation and other uses includ- ing that of ground water extracted from the San Pedro formation, and possibly by lateral movement of ground water from volcanics in both Tierra Rejada and Conejo Basins. Ground water storage in the San Pedro formation is recharged by percolation of flow in minor watercourses, by 2-100 deep penetration of direct precipitation on its outcrop area along the north side of the basin, and possibly by lateral underflow from the vol- canic rocks. Ground water storage is depleted by pumped extractions to meet beneficial consumptive use on overlying lands, by effluent discharge, and by some subsurface outflow to Pleasant Valley Basin. Wells in Santa Rosa Basin are reported to yield as much as 1,200 gallons per minute, with an estimated average yield of about 600 gallons per minute. Water level fluctuations at key well number 2N/20W-23R1, which is perforated in the alluvium, are shown on Plate 20. It may be noted that although water levels in this well showed substantial recovery dur- ing the wet period, there was a net lowering of about 20 feet during the base period. The average decrement in ground water storage in the basin during the base period was estimated to have been about 200 acre-feet per season. The estimated seasonal consumptive use of applied water during the base period was about 3*100 acre-feet. An import from Tierra Rejada Basin in the amount of about 5>00 acre-feet per season satisfied a portion of this consumptive use. It was estimated that during the base period there was a small subsurface outflow to Pleasant Valley Basin in an amount not in excess of 200 acre-feet per season. Quality of Water Surface and ground water supplies of Ventura County are general- ly of good mineral quality and suitable from that standpoint for irriga- tion and other beneficial uses. Notable exceptions are found in the waters of some minor surface streams and in the low flows of several major streams, as well as in ground waters found in some portions of the County. It has been reported that in certain areas crops have suffered injury . 2-101 from application of waters containing high boron concentrations. In ad- dition it has been reported that crops in some localities have suffered from excessive soil salinity during drought periods, which is an indica- tion that normal rainfall is a factor in keeping soil salinity within acceptable limits. In a number of ground water basins in Ventura County, it appears that the average seasonal quantity of dissolved salts added to ground water supplies exceeds the average seasonal quantity removed. Thus an unfavorable salt balance is created which, if continued, may seriously affect the quality of ground water in the basins. Plans for water supply development to eliminate present overdrafts on ground water basins and to satisfy probable future water requirements must also provide sufficient water to maintain a satisfactory salt balance in ground water basins. The Division of Water Resources is presently conducting a detailed County-wide investigation of water quality and water quality problems in Ventura County, in accordance with sections 229 and 230 of the Water Code. Since results of that investigation will be published in the near future, water quality date and discussion herein are limited to a general presentation of factors which affect the suitability of available water supplies for prevailing beneficial uses. The following terms are used, as defined, in connection with the discussion of quality of water in this bulletin: Quality of Water — Those characteristics of water affecting its suitability for beneficial uses. Contamination — Impairment of the quality of water by sewage or industrial waste to a degree which creates a hazard to public health through poison- ing or spread of disease. 2-102 Degradation — Impairment of the quality of water due to causes other than disposal of sewage and industrial wastes. Pollution - -Impairment of the quality of water by sewage or industrial waste to a degree which does not create a hazard to public health, but which adversely and unreasonably affects such water for beneficial use. Mineral Analyses — The quantitative determination of inorganic impurities or dissolved mineral constituents in water. Complete mineral analyses reported in this bulletin include determination of calcium, magnesium, sodium and potassium, bicarbonate, carbonate, chloride, sulphate and nitrate, fluoride, boron, total dis- solved solids, electrical conductance (EC x 10 6 at 25°C), per cent sodium, and effective salinity. Partial mineral analyses include determinations of chlorides, bicarbonates, and electrical conductance. In some instances boron determination was included in the partial mineral analysis. In general, the concentrations of principal constituents deter- mined in a complete mineral analysis are expressed herein as "equivalents per million". Exceptions to this are boron, fluoride, and total dissolved solids. Reporting, in equivalents per million was done because ions com- bine on an equivalent basis rather than on a weight basis, and a chemical equivalent unit of measurement provides a more convenient expression of concentration. This is particularly true when it is desired to compare the composition of waters having variable concentrations of mineral con- stituents. In the cases of boron, fluoride, and total dissolved solids, concentrations are reported on a weight basis of "parts per million". To convert equivalents per million, or "epm", to parts per million, or "ppm", the concentration in equivalents per million should be multiplied by the equivalent weight of the ion. Equivalent weights of the principal con- 2-103 stituents found in water supplies are presented in the following tabula- tion: Cation Equivalent weight Anion Equivalent weight Calcium 20.0 Carbonate 30.0 Magnesium 12.2 Bicarbonate 61.0 Sodium 23.0 Chloride 35.5 Potassium 39.0 Sulphate U8.0 Nitrate 62.0 Data used to determine the quality of water in Ventura County included 273 complete and 156 partial mineral analyses of surface water, and 1,161 complete and 1,080 partial mineral analyses of ground water. Standards of Quality for Water The waters of Ventura County are used for irrigation, domestic, and municipal and industrial purposes. Suitability of the waters for each of these uses depends in part upon the amount and kind of dissolved minerals they contain. Water quality criteria and standards for the above named uses are discussed in the following paragraphs: Irrigation Use . The major criteria used as a guide to judge the suitability of water for irrigation use usually comprise the following: (1) chloride concentration, (2) conductance (EC x 10^ at 25°C), (3) boron concentration, and (ii) per cent sodium. (1) Chlorides are present in nearly all waters. They are not considered essential to plant growth, and may be especially harmful in high concentrations as they cause subnormal growing rates and burning of leaves . (2) Conductance (EC x 10^ at 25°C) is an indicator of the total 2-lOU dissolved solids, and as such, furnishes an approximate indication of the overall mineral quality of the water. For most waters, the total dis*< , - solved solids may be approximated by multiplying the conductance by 0.7» The presence of excessive amounts of dissolved salts in irrigation water will result in reduced crop yields and burning of leaves. (3) Boron in nature is never found in the uncombined or elemental state but occurs in the form of boric acid, or more commonly as borates. This element is essential in small amounts for the growth of many but not all plants. It is, however, extremely toxic to most plants in higher concentration. Limits of tolerance for most irrigated crops vary from 0.5 to 2.0 ppm. Citrus, particularly lemons, is sensitive to boron in concentrations exceeding 0.5 ppm. (h) Per cent sodium reported in the analyses is the proportion of the sodium cation to the sum of all cations, and is usually obtained by dividing sodium by the sum of the amounts of calcium, magnesium, and sodium, all expressed in equivalents per million, and multiplying by 100. Water containing a high per cent sodium has an adverse effect upon the physical structure of the soil by dispersing the soil colloids and making the soil "tight", thus retarding movement of water through the soil, retarding the leaching of salts, and making the soil difficult to work. When potassium is present in water in significant amounts, its effect on soils is similar to sodium. The following excerpts from a paper by Dr. L. D. Doneen, of the Division of Irrigation of the University of California at Davis, may assist in interpreting water analyses from the standpoint of their suita- bility for irrigation: "Because of diverse climatological conditions, crops, and soils 2-105 • in California, it has not been possible to establish rigid limits for all conditions involved. Instead, irrigation waters are divided into three broad classes based upon work done at the University of California, and at the Rubidoux, and Regional Salinity Laboratories of the United States Department of Agriculture. "Class 1. Excellent to Qood — Regarded as safe and suitable for most plants under any condition of soil and climate. "Class 2. Good to Injurious — Regarded as possibly harmful for certain crops under certain conditions of soil or climate, particularly in the higher ranges of this class. "Class 3. Injurious to Unsatisfactory— Regarded as probably harmful to most crops and unsatisfactory for all but the most tolerant. "Tentative standards for irrigation waters have taken into account four factors or constituents, as listed below: Factor Class 1 excellent to good Class 2 good to injurious Class 3 injurious to unsatisfactory Conductance (EC x 10 6 at 25°c) Less than 1,000 1,000-3,000 More than 3,000 Chloride, epm Less than 5 5-10 More than 10 Per cent sodium Less than 60 60-75 More than 75 Boron, ppra Less than 0.5 0.5-2.0 More than 2.0 (End of quotation) •The values shown in the foregoing tabulation should be used as a guide only, since permissible limits vary widely with different crops, soils, and climatic conditions. Actual practice in Ventura County indicates that waters rated as class 2 and 3 by the foregoing standards particularly in regard to conductance, are successfully used to irrigate 2-106 citrus. Accordingly, a new method of calculating salinity of irrigation water together with revised standards therefore has been suggested by Dr. Doneen as follows : "This proposed standard for total salts of an irrigation water is based on the premise that the salts will accumulate in the soil due to evaporation from the soil surface and water used by the plants in trans- piration. Plants usually remove only a small percentage of the total salts occurring in the irrigation water. As the soil solution becomes concentrated certain salts will precipitate. Because of the low solubi- lity, the first to precipitate will be calcium carbonate, followed by magnesium carbonate and finally by calcium sulfate. These salts will not produce a saline soil. Other salts normally occurring in irrigation water in any significant concentration are extremely soluble and accumulate in the soil solution as salines. These salines are listed as 'effective salinity 1 . Therefore, calcium and magnesium carbonates and calcium sul- fate should not be considered in establishing standards for total salinity as is now the practice in the use of electrical conductance, total parts per million or milliequivalents per liter concentration." Using this method, Dr. Doneen has tentatively suggested the following. criteria of effective salinity for classification of irrigation waters under three soil conditions: Class 1 Class 2 Class 3 excellent good to injurious to Soil conditions to good injurious unsatisfactory Effective salinity, in epm Little or no leaching of the soil may be expected Less than 3 3-5 More than 5 Some leaching, but restricted. Deep percolation or drainage slow Open soils. Deep percolation of water easily accomplished Less than 5 5-10 More than 10 Less than 7 2-107 7-15 More than 15 Review of the soil survey of Ventura County made by the United States Department of Agriculture indicates that most of the irrigable lands in the County are classified as open soils. For this reason, criteria for soils of this condition will apply throughout this discus- sion unless otherwise stated. Domestic and Municipal Use . Probably the most widely used criteria for determining the suitability of water for domestic and muni- cipal use are the "United States Public Health Service Drinking Water Standards, I9I46". The individual standards considered pertinent to the discussion presented hereinafter are shown on Table 17* TABLE 17 UNITED STATES PUBLIC HEALTH SERVICE DRINKING WATER STANDA1DS 19U6 Should not exceed" PPm Constituent Total Solids Magnesium (hg) Chloride (Cl) Sulphate (SO, ) Zinc (Zn) Fluoride (F) 500 (1,000 permitted) 125 250 250 15 l.5 (b) (a) (a) Where alternate source of water unavailable. (b) Limits for this constituent mandatory; for others recommended. Total hardness is a significant factor in the determination of the suitability of a water for domestic and municipal use. It is caused principally by compounds of calcium and magnesium, although other sub- 2-108 stances such as iron, manganese, aluminum, barium, siliea, strontiusv-and free hydrogen contribute to total hardness. The effect of hardness in water is primarily economic, in that its presence requires an increased use of soap, which it coagulates to form an insoluble precipitate. It also causes formation of scale which tends to reduce the efficiency of boilers and plumbing systems. With suitable treatment, however, hardness can readily be removed or reduced to acceptable limits. Water containing 100 ppm or less of hardness (as CaCOo) are considered as "soft" herein; those containing 101 to 200 ppm are considered "moderately hard"; and those with more than 200 ppm are considered "very hard". Industrial Use . The foregoing standards for domestic and muni- cipal use are considered applicable for prevailing industries in Ventura County. Quality of Surface Water The mineral quality of surface water in Ventura County is extremely variable both a really and with the rate of stream flow. At times of low flow in many streams the water contains excessive mineral concentrations, particularly of boron and sulphate. Because of the varia- bility in quality of surface water, each hydrologic unit is discussed separately herein. Representative analyses showing mineral quality of the waters in principal streams, and variations in quality with rate of flow, are presented in Table 18. The locations of surface sampling stations for which analyses are shown in Table 18 are delineated on Plate 7, entitled "Stream Gaging and Water Sampling Stations". Ventura Hydrologic Unit . Waters of Matilija Creek, Coyote Creek, and the Ventura River above Foster Park, generally are of good quality and 2-109 suitable for prevalent beneficial uses. Although at low flow stages in Matilija Creek the water contains boron concentrations as high as 6.5 ppm> water stored in Matilija Reservoir in May, 1952, showed only 0.34 ppm of boron. Below Foster Park, waters containing excessive concentrations of sulphates and boron are added to the Ventura River by tributaries, parti- cularly by Canada Larga, even at relatively high rates of flow. As a result of these tributary inflows, water of Ventura River below Foster Park is generally considered unsuitable for domestic purposes, and of class 2 to class 3 for irrigation use. Santa Clara River Hydrologic Unit . Water in the Santa Clara River in Ventura County is generally of good mineral quality for irriga- tion and other prevailing beneficial uses. However, it is seldom of excellent quality except during periods of relatively high flow. Effec- tive salinity rarely exceeds 10 epm even during times of low flow. Mineral analyses indicate that water flowing in Santa Paula Creek is of good to excellent mineral quality even during low flow stages. Water of Sespe Creek is generally of good to excellent mineral quality for irriga- tion, and suitable for domestic use, for flows in excess of 60 second- feet near its mouth. For flows less than 60 second-feet, analyses indi- cated that water contains concentrations of boron varying from 0.7 to over 4 ppm, thus rendering it marginal to unsatisfactory for irrigation use. Mineral analyses indicate that water flowing in Hopper Creek is generally unsatisfactory for irrigation use, except during periods of flood flow. Like Sespe Creek, water flowing in Piru Creek contains high concentrations of boron at low flow stages. Based upon many analyses, it was concluded that flows must exceed 200 second-feet at the U.S.G.S. gaging station near the town of Piru before the boron concentration is 2-110 1 : I ' * i * j ' J S , 1 * reduced to values of 1.0 ppm- or less-. From the standpoint of its other .' ' .mineral constituents, Piru Creek water is of* good quality' for, irrigation purposes at all flow stages, although at low flow stages total solids and sulphate concentrations exceed the prescribed limits for domestic use. Waters of some of the minor tributaries of the Santa Clara River contain high concentrations of sulphate. However, their effect on the general mineral quality of the river water is considered to be negligible. Calleguas-Cone.jo Hydrologic Unit . The mineral quality of sur- face water in this hydrologic unit varies considerably. It is generally unsuitable for irrigation or other prevailing beneficial uses during low flow stages, but during flood stages the quality is generally good. Typical examples of poor mineral quality in surface streams at low flow stages in this hydrologic unit are shown in analyses of waters from Arroyo Simi and Tapo Creek, which contained dissolved solids of 7,057 and 4,122 ppm, ' respectively.' • ► Malibu Hydrologic Unit . There is a paucity of data concerning the mineral quality of surface water in the Malibu Hydrologic Unit. How- ever, single available analyses for Big and Little Sycamore Creeks indi- cate that these waters are suitable for prevailing beneficial uses. 2-111 I « >- — tu z o X Q_ uj O - U V) o UJ z 3 00 UJ — O ■< UJ u. _) cc CO =3 <: eo t— u. o eo UJ CO V -J «t 2 «£ -J r o co CO o o CO o u OCO zoo 4 _ ©" U X ™ s a O fr- Z UJ O « — ' o H m ul UJ Ul CP u. 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Although not actually a source of impairment to ground water quality in themselves, improperly constructed, defective, and abandoned wells may be a factor in transmission of pollution, contamina- tion, or degradation to usable ground waters, through the introduction of surface or drainage waters or the leachings from cesspools and septic tanks. Such wells may allow the interchange of waters between aquifers having differing quality characteristics, thus degrading good quality waters. Natural Sources . The mineral quality of water is adversely affected by natural causes in several portions of Ventura County. In general, this natural degradation is a minor source of impairment to the quality of surface and ground waters. Sespe and Piru Creeks receive small flows of water with high boron concentration originating from abandoned mining operations. In addition, Piru Creek water is degraded by boron originating in colemanite deposits in Lockwood Valley. It is believed that the relatively high concentrations of boron noted in ground water of Piru Basin are primarily the result of percolation of the degraded Piru Creek water in the basin. In the vicinity of South Mountain and the Topatopa Mountains, natural seeps of connate brines reportedly occur, con- taining high concentrations of dissolved salts. These brines drain into Santa Paula Creek, the Santa Clara River, and Ojai Valley. It is reported 2-127 that there are three springs on Upper Matilija Creek from which emanate waters of high boron content, which adversely affect the quality of low flows of Matilija Creek. Domestic Sewage . Domestic sewage returning to ground water through cesspools, septic tanks, and leach lines, or from community treatment plants, is of higher mineral content than the source water. In- vestigations have shown increases of 20 to $0 ppm in chlorides, 30 to 60 ppm in sodium, and 15 to 25 ppm in nitrogen* some of which may oxidize to NOo. These increases in mineral content are so small, however, that domestic sewage in the Santa Clara River Valley, Upper Ventura River Valley, and Ojai Valley may be considered as a satisfactory source of ground water replenishment, and from this standpoint susceptible of treatment and conservation. However, as was mentioned heretofore, most waters in Ventura County are considered to be very hard. Concentrated salt wastes resulting from the regeneration of individually owned soften- ing units could render the quality of sewage unsuitable for reuse, and cause localized pollution problems. Similar problems could be created by imprudent discharge by central regeneration plants. Irrigation Return Water . Irrigation of agricultural crops requires an application of water in excess of the consumptive requirement for water to prevent undue build-up of salts in the root zone. This excess water, or irrigation return water, may contain from two to as many as ten times the concentration of salts found in the original water supply. In the Oxnard Plain and Mound Basins, where the pumped aquifers are confined, subsurface and open drains have been constructed to remove ^Values are from paper, "The Mineral Pickup Resulting from the Utiliza- tion of Water for Domestic Purposes", given at American Geophysical Unioi by Ralph Stone, February, 1952. 2-128 the irrigation return and rainfall percolate. Analyses show these drain- age waters to contain from 1,800 to over 5*000 ppm of total dissolved solids. In areas where irrigation return water can percolate to the ground water, it may constitute an important source of degradation to the water supply. Industrial Wastes . The development of natural resources and the growth of industry, including agriculture, in Ventura County hare created a multitude of waste disposal problems. Whenever harmful liquid or water soluble industrial wastes are discharged into stream channels, onto the ground, or into unlined sumps, they constitute a threat of pollution to underlying ground water. Sources of industrial wastes in Ventura County include the oil industry, citrus and walnut packing plants, refuse disposal sites, slaughter houses, and hog farms. Wastes derived from the oil industry include connate brines of high salt content pumped from the oil sands, and "contaminated" drilling muds. Wastes from citrus packing houses may in- clude any one, or a combination of borax, soda ash, sodium hypo-chlorite, and/or soap, depending upon the individual plant operation.. Wastes from walnut packing houses usually contain high concentrations of sodium chloride. Refuse disposed of in dumps will on decomposition release salts, which when dissolved by rainfall or applied water may percolate to ground water. Wastes from slaughter houses and garbage on hog farms is usually of an organic nature, which if not suitably treated or handled may produce septicity in water supplies, with accompanying foul odors. Sea-Water Intrusion . In the Oxnard Plain Basin, it was noted that mineral analyses of water from certain wells in the vicinity of Port Hueneme during the recent drought period evidenced higher concentra- tions of chlorides and dissolved solids than did other water from the 2-129 Oxnard aquifer. In Table 21 there are presented complete mineral analy- ses of waters from wells so affected. A thorough study of this portion of the aquifer reduced the probable sources of chloride degradation in the ground water to one or more of the following: 1. Sen water intrusion through the Oxnard aquifer. 2. Percolation, or leakage through poorly constructed wells, defective casings, or abandoned wells of: a. Irrigation return water and other poor quality waters from the semi -perched ground water body. b. Sea water which had intruded into the semi -perched ground water body. A method of differentiating between ground water degraded by sea-water and by semi -perched ground water is by comparison of the character of the two waters with that of the degraded ground water. This may be conveniently done employing a geochemical chart, by use of which the chemical character of waters can be graphically depicted. If two waters of different character are mixed, it is logical to presume that the character of the resulting mixture will be a combina- tion of the characters of the two waters. Thus, if the character of waters from sources of degradation are plotted on a geochemical chart, together with the character of the degraded water, the source of degrada- tion may become apparent. Plate 22, entitled "Mineral Character of Ground Water in Vicinity of Port Hueneme and Point Mugu", shows on geochemical chart "A" the anion constituents, expressed in per cent, in the degraded water and in the two apparent sources of degradation. Also plotted on this chart are anion constituents in ground water from these wells prior to degradation. Inspection of Plate 22 will show that the indicated source of degradation of water from wells in the vicinity of Port Hueneme was sea water. The character of the anion constituents in the degraded ground water plots almost in a direct line between the character of 2-130 undegraded ground water and ses water. There was no apparent influence of the ground water found in the semi -perched body on the character of the degraded ground water. Anion constituents only were used in this chart, since cation constituents are subject to character changing influences such as cation exchange. In an effort to distinguish between possible methods by which sea water entered the Oxnard aquifer, consideration was given to the hy- drologic and geologic conditions that existed in the area of intrusion. As described previously, the Oxnard aquifer appears to outcrop in the sub- marine canyon near Port Hueneme. Furthermore, the semi-perched zone ap- pears to extend under the coastal sand dunes to the ocean. Thus, from the geologic standpoint, sea water might enter either of these two water- bearing zones. Before sea water could intrude, however, a condition would have to exist whereby the hydraulic head of the sea water was greater than that prevailing in the respective aquifers. Concerning this possibility in the semi-perched zone, information obtained from studies of the Division of Irrigation and Soils of the University of California at Los Angeles was of significance. This agency determined elevations of the perched water table throughout the Oxnard Plain Basin, as a part of its study of drainage problems. These elevations indicated that through- out the basin the perched water surface sloped toward the, ocean and exceeded mean sea level, thus precluding the possibility of sea water intrusion thereto. Subsequent to 19h9 with the prevailing trough in the piezometric levels in the Oxnard aquifer, conditions were conducive to the intrusion of sea water. A correlation between elevations of the piezometric surface in Oxnard aquifer and increase in chloride concentration in the ground in 2-131 the Oxnard aquifer and saline intrusion is indicated on Plate 23, entitle "Elevation of Ground Water and Chloride Ion Concentration", On this plat there is plotted the hydrograph of well number 1N/22W-20R1, together with the average weekly chloride ion concentration in water from well number 1N/22W-29A2, both of which are perforated in the Oxnard aquifer. An inspection of Plate 23, will show that during the period when the water surface elevation in well number 1N/22W-20R1 was lowest, the rate of in- crease in chloride concentration in the ground water was the greatest, once degradation had started. As an example, during the period from September 1st until about the 13th of December, 1951, the elevation of the water surface in well number 1N/22W-20R1 slowly increased from about minus Ik feet to about minus 2 feet, and the rate of increase in chloride concentration in water from well number 1N/22W-2°A2 averaged 3.9 ppm per day. In the subsequent period, December 13, 1951 to March 15, 1952, water surface elevations averaged slightly above sea level, and the rate of increase in chloride concentration in the water was reduced to about 1.5 ppm per day. Although it appears anamalous that the chloride concen- tration should have increased while water surface elevations in the key well slightly exceeded sea level, consideration should be given to the fact that the top of the Oxnard aquifer in this vicinity is between 80 to 120 feet below sea level, and that the specific gravity of sea water exceeds that of fresh water. In view of this, a water surface elevation in the Oxnard aquifer of more than two feet is required in order to main- tain equilibrium with the sea water. Furthermore, prior to May, 1952, the prevailing piezometric level in parts of the central portion of the basin was below sea level, so that an overall landward gradient was maintained. In view of the lack of required hydraulic slope for intrusion 2-132 through the semi-perched zone, together with the observed correlation between water surface elevations in the Oxnard aquifer and jthe increase in chlorides, it appears that sea water has entered -- direetiljy into the Oxnard aquifer. The determined extent of saline intrusion in Oxnard Plain Basin has been limited to an area in the immediate vicinity of Port Hueneme, as shown on Plate 16-B, and has been apparent only in wells numbers 1N/22W-20N1, 1N/22W-20R1, 1N/22W-29A2, and 1N/22W-29C1. Ground water in well number 1N/21W-28D1, which was perforated in the Oxnard aquifer, and was reported in Division of Water Resources Bulletin Mo. 46 to have been degraded by the intrusion of sea water, recovered its former quality with increase in piezometric levels above sea level and recession of sea water from the aquifer. This improvement in quality is depicted on geochemical chart B on Plate 22. . ! ! ■ 2-133 , / — 1 UJ «* X. 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MM tn to lf> ■«»- (— 00 CO CM CO CM CM CM CM 1 1 1 . 1 1 1 ■ | 1 1 CO u-> IT) (*- o> — CO CO o> — CM CM «S CO CM I to CO f- ■<* s. co o 1 2-136 o z o 3 CJ • u. cr « CO tu to t- t- tu z z 1 - z > O CD X mm Mj - > cr CO CD u. 1- co CO CO CO MM M§ «. Mi £3 ca co CO CO CO Ul tu >■ >- > > -I -I -1 -1 -1 _i CL a. «t •« «t < E E z z z z «t «I < 0-5l constituted the critically deficient water supply portion of this period. In general, estimates of safe yield are presented in this bulletin in terms of seasonal rate of yield. The term "net safe yield" refers to that portion of the safe yield re- sulting from a proposed new water supply development and method of operation thereof that would have been wasted without the proposed works and under the pres- ent pattern of land and water utilization, and is used synonymously with the term "new water". When used in reference to water supplies available from ground water storage, the term "safe yield" refers to the maximum rate of net extraction from the ground water basin which, if continued over an indefinitely long period of years, would result in the maintenance of certain desirable fixed conditions, 2-13? Commonly, safe ground water yield is determined by one or more of the following criteria: 1. Mean seasonal extraction of water from the ground water basin does not exceed mean seasonal replenishment to the basin. 2. Water levels are not so lowered as to cause harmful impairment of the quality of the ground water by intrusion of other water of undesirable qual- ity, or by accumulation and concentration of degradants or pollutants. 3. Water levels are not so lowered as to imperil the economy of ground water users by excessive costs of pumping from the ground water basin or by ex- clusion of the users from a supply therefrom. In the determination of the safe yield of ground water basins of Ventura County, it was found that each of these criteria applied to one or more of the basins. Commonly, safe yield of a ground water basin is not determined until there is evidence of overdraft or use of water in excess of safe yield. Many of the basins in Ventura County are now experiencing such overdraft. On the other hand, others are not being utilized to the maximum extent possible under limita- tions imposed by the foregoing criteria. With increased use of these presently underdeveloped basins, ground water levels would be further lowered during drought periods, thereby providing additional space in the basins for storage of percolat- ing surface waters that would otherwise waste to the ocean during wet periods. The effect thereof would be en increase in yield of the basins. Furthermore, in certain basins where overdraft now prevails, it appears that safe yield could be increased through modification of the present pumping patterns. Since safe ground water yield is not a fixed value but is a function of pumping patterns and the magnitude of ground water basin utilization, together with other factors, further definition of the term is considered necessary. As used in this bulletin, therefore, the term "safe ground water yield" refers to the maximum rate of net extraction of ground water that could be maintained over 2-138 Safe Yield of Presently Developed Water Supply An evaluation of the safe yield of existing sources of water supply in Ventura County under present conditions of development and utilization is pre- sented in this section. As has been stated previously, surface storage develop- ments and uncontrolled stream flow comprise only secondary sources of water sup- ply in the County, while water stored in ground water basins presently constitutes the primary source of supply. The term "safe yield", when used in this bulletin in connection with a surface storage development, refers to the maximum sustained rate of draft from the reservoir that could have been maintained throughout a critically deficient water supply period, VJhen used in connection with a diversion from the unregu- lated flow of a surface stream, the term similarly refers to the maximum sustained rate of diversion from the stream that could have been maintained throughout a critically deficient water supply period. Water supplies as they occurred during the base period from 1936-37 through 1950-51 were utilized in determining safe yield of surface reservoirs and surface stream diversions in Ventura County. In most cases the dry seasons from 19hh-U5 through 193>0- 5>1 constituted the critically deficient water supply portion of this period. In general, estimates of safe yield are presented in this bulletin in terms of seasonal rate of yield. The term "net safe yield" refers to that portion of the safe yield re- sulting from a proposed new water supply development and method of operation thereof that would have been wasted without the proposed works and under the pres- ent pattern of land and water utilization, and is used synonymously with the term "new water". When used in reference to water supplies available from ground water storage, the term "safe yield" refers to the maximum rate of net extraction from the ground water basin which, if continued over an indefinitely long period of years, would result in the maintenance of certain desirable fixed conditions. 2-137 Upper Ojai Subunit , The source of water supply for the Upper Ojai Sub- unit is ground water in Upper Ojai Basin. Since it appears that natural replen- ishment is satisfying the present relatively minor water requirements of the water users, the safe yield of this basin was taken as equal to the estimated average seasonal net extraction of water therefrom during the base period, or about UOO acre-feet per season. It is believed that this amount represents about the maxi- mum rate of extraction that could be maintained from the basin, Ojai Subunit . Since water requirements of the Ojai Subunit for both lands overlying the ground water basin and lands overlying adjacent nonwater- bearing formations are supplied by pumping from Ojai Basin, the safe yield of the water supply of the subunit was taken as equal to that estimated for the ground water basin. As stated previously, from the spring of 19U4- to the fall of 19E>1> net retention of tributary surface runoff and of direct precipitation in Ojai Basin totaled an estimated U3>000 acre-feet. Of this amount, it was estimated that consumptive use of direct precipitation, and consumptive use of ground water by phreatophytes amounted to about U2,800 acre-feet, leaving only a negligible amount to meet extractions of water from the basin for beneficial use. However, an estimated 10,900 acre-feet of water stored in the ground water basin in the spring of 19hh could have been extracted without violating the third of the cri- teria governing safe ground water yield. Thus, the safe yield of Ojai Basin was estimated as the summation of the two items of supply, amounting to about 11,100 acre-feet, divided by the number of seasons in the period of analysis, or about 1,!?00 acre-feet per season. Upper and Lower Ventura River Subunits . Stream flow originating in Matilija and the North Fork of Matilija Creeks, ground water in Upper Ventura River Basin and in Mound Basin underlying Lower Ventura River Basin, and ground water in low-yielding sediments east and west of the Ventura River above Foster Park comprise the sources of water supply of the Upper and Lower Ventura River 2-LU0 Subunits. Since 19U8, runoff in Matilija Creek has been regulated by Matilija Reservoir. It was estimated that during the drought period, if Matilija Reservoir had not been in operation, about h 9 900 acre-feet per season would have been available to meet requirements of ground water users in Upper Ventura Basin and of diverters of surface flow between the confluence of Matilija and the North Fork of Matilija Creeks to and including the diversion of the City of Ventura at Foster Park. This supply was taken as the safe seasonal yield of these water sources. Of the estimated h 5 900 acre-foot safe seasonal yield, it was determined that about 3,900 acre-feet would have been available for pumpage or diversion by the City, and that about 1,000 acre-feet would have been available for surface and ground water users above Foster Park. Had Matilija Dam been in operation during the drought period, it was estimated that the reservoir would have last filled in the spring of 19U7* and that with an average seasonal draft of 3, 700 acre-feet during the ensuing four and one-half year period the reservoir would have been empty by the fall of 195l» It was further estimated that about 2,300 acre-feet of the average seasonal draft from the reservoir would have been put to beneficial use by users above Foster Park, including the City of Ventura, even if the reservoir had not been in oper- ation. Thus, the net safe yield developed by Matilija Reservoir would have aver- aged about 1,U00 acre-feet per season. It is known that during the drought period many wells drawing from the minor ground water sources in the Upper Ventura River Subunit, and supplying lands east and west of the Ventura River above Foster Park, went dry. The average re- quirement for consumptive use of applied water on these lands was estimated to have been about 800 acre-feet per season. Safe yield of the minor ground water sources was estimated to have been equal to about 60 per cent of this requirement, or about !?00 acre-feet per season. This estimate was based on the assumption that 2-lUl these sources yielded no more water in proportion to the requirement of land served therefrom than did other ground water sources in Upper Ventura River Ba- sin and surface flow in the Ventura River. The portion of the safe yield of Mound Basin available to meet water requirements in the Ventura Hydrologic Unit was taken as equal to the average seasonal extraction of ground water therefrom during the base period by users in the Lower Ventura River Subunit west of the Ventura River, or an estimated 600 acre-feet per season. This amount includes an estimated 100 acre-feet of water per season extracted in this area and exported for use in the Rincon Subunit. The extraction of ground water from Mound Basin by the City of Ventura from 19U7- I4.8 through l°5>0-5l was considered to have been but a temporary expedient, and it was assumed that this source would not be available indefinitely to the City. This assumption was based on the fact that a pumping depression, with its center considerably below sea level, formed in the piezometric surface of the aquifer in Mound Basin when the city wells were operating. Thus, conditions were conducive to the intrusion of sea water into the pumped aquifer. It is probable that the principal source of replenishment to the aquifer is percolation of direct preci- pitation and of surface flow in minor watercourses in the outcrop area of the San Pedro formation north of the City, which supplies appear to be inadequate to sat- isfy the pumping demands on this portion of the aquifer. Rincon Subunit . In addition to the aforementioned import from the Lower Ventura River Subunit, some water in the Rincon Subunit is obtained by pumping from small ground water basins at the mouths of several minor streams discharging to the ocean along the coastal front. The safe yield of these minor ground water basins was estimated to be about 100 acre-feet per season, which amount was taken as the safe yield of the Rincon Subunit. It is known that many wells in the sub- unit were dry during the latter years of the drought period. This fact, together with the prevailing poor quality of certain of the ground waters, necessitated trucked importation of drinking water for many users. 2-11*2 Santa Clara River Hydrologic Unit Since water requirements of the Santa Clara River Hydrologic Unit are largely met by pumping from ground water storage, the safe yield of presently de- veloped water supplies therein was taken as the safe yield of the ground water basins, estimated to be about 72,200 acre-feet per season. This estimate, how- ever, includes the relatively minor yield of surface waters diverted and utilized in the hydrologic unit. No differentiation was made between yield of surface and ground water sources, since it is probable that diverted surface water would otherwise percolate and be retained in the ground water basins. Furthermore, it was assumed that in the free ground water areas the unconsumed residuum of sur- face waters applied to urban and irrigated lands would return to ground water storage and be available for re-use. The total safe water supply available to meet requirements in the Santa Clara River Hydrologic Unit was estimated to be about 73,200 acre-feet per season. This supply is comprised of the foregoing safe yield of about 72,200 acre-feet per season, less an export from the Oxnard Forebay Subunit to the West Las Posas Sub- unit of the Calleguas-Conejo Hydrologic Unit averaging about 1,100 acre-feet per season, plus average seasonal imports of Santa Clara River water from Los Angeles County to the Eastern and Piru Subunits totaling about 2,100 acre-feet. Table 23 summarizes the estimated safe seasonal yield of the presently developed water supply in the Santa Clara River Hydrologic Unit. The values shown for the Eastern and Piru Subunits do not include the aforementioned imports from Los Angeles County. The total value for the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits .does include the cited export to the Calleguas-Conejo Hydrologic Unit. 2-1U3 TABLE 23 ESTIMATED SAFE SEASONAL YIELD OF PRESENTLY DEVELOPED WATER SUPPLY IN SANTA CLARA RIVER HYDROLOGIC UNIT Subunit : Acre-feet " Eastern Pirn 11,100 Fillmore 10,000 Santa Paula l£,600 Mound 8,800 Oxnard Forebay, Oxnard Plain, 26, 700 and Pleasant Valley TOTAL 72,200 Eastern Subunit . Water supplies for developed lands in the Eastern Sub- unit, so far as could be determined, are obtained entirely by importation of Santa Clara River water from Los Angeles County in the estimated average amount of about 300 acre-feet per season. Piru, Fillmore, and Santa Paula Subunits . Derivation of the safe sea- sonal ground water yields of Piru, Fillmore, and Santa Paula Basins, which, as stated previously, were taken as the yields of the water supplies of the respec- tive subunits, is shown in Table 2U. The values in the table for items tending to increase and decrease yields of the basins are estimated average seasonal quan- tities over the base period. Derivation of values for consumptive use of precipi- tation was based on analyses discussed in Chapter III, and the values given in- clude consumptive use of ground water by phreatophytes. The estimate of safe yield of Piru Basin does not include an average seasonal import of about 1,800 acre-feet of water from Los Angeles County. 2-Ujli TABLE 2ii ESTIMATED SAFE SEASONAL YIELD OF PIRU, FILLMORE, AND SANTA PAULA GROUND WATER BASINS (In acre-feet) : Basin Item : Piru : Fillmore: Santa Paula Items tending to increase yield Surface inflow 102,000 176,900 Subsurface inflow 20,600 Precipitation on basin 9,600 25,800 209, 700 11, 5oo 18,500 Subtotals to be added 111,600 223,300 239,700 Items tending to decrease yield Surface outflow 72,900 Subsurface outflow 20,600 Consumptive use of precipitation 7,000 Subtotals to be subtracted 100,500 181,300 11,500 20,500 213,300 203, 200 7,200 13, 700 22U,100 SAFE YIELD 11,100 10,000 15,600 It should be noted that the derived "safe yields" shown in Table 2k are not the maximum yields which could be developed in these basins. As stated in an earlier section, utility of the Piru, Fillmore, and Santa Paula Basins is limited largely by factors of economic pumping lift and mean seasonal recharge, and not by storage capacity or configuration of the basins. Therefore, it appears that their yields could be increased to the limit of mean seasonal recharge if not prohibited by economic considerations. Achievement of such increases, however, would require greater utilization of the basins than with present patterns of land use and water supply development, and greater ranges in pumping lifts, and might result in the creation of adverse salt balances in the basins. It should be further noted in Table 2lt that the safe yield indicated for a given basin is not necessarily the amount of water that is available for use in that basin. In Piru Basin, of the indicated safe yield of about 11,100 2-H5 acre-feet per season, some 5,700 acre-feet per season represents an export to Fillmore Basin. The estimated safe water supply available to meet requirements in Piru Basin is comprised of the indicated safe yield less this export, plus the aforementioned import from Los Angeles County in the amount of about 1,800 acre- feet per season, or a total of about 7,200 acre-feet per season. In Fillmore Ba- sin, of the indicated safe yield of about 10,000 acre-feet per season, approxi- mately 1,U00 acre-feet per season is exported to Santa Paula Basin. Therefore, the estimated safe water supply available to meet requirements in Fillmore Basin is comprised of the indicated safe yield less the export, plus the import from Piru Basin, or a total of about lU,300 acre-feet per season. Of the indicated safe yield in Santa Paula Basin of some 15,600 acre-feet per season, about 600 acre-feet per season is exported to Mound Basin and about 700 acre-feet to Oxnard Plain Basin. The estimated safe water supply available to meet requirements in Santa Paula Basin, therefore, is comprised of the indicated safe yield less the exports, plus the import from Fillmore Basin, or a total of approximately 15,700 acre-feet per season. Mound Subunit . Safe yield of the Mound Subunit was taken as equal to that portion of the average seasonal extraction of ground water from Mound Basin that was utilized within the Mound Subunit during the base period, or an estimated 8,800 acre-feet per season. This estimate does not include extractions of water from Mound Basin by the City of Ventura nor by users west of the Ventura Paver. Since independent evaluation of the amount of recharge to Mound Basin during the drought period could not be made with data at hand, it is possible that experience will show that the foregoing estimate of safe yield is excessive. In this connection, it appears that in the westerly portion of the basin near the ocean, where ground water levels were below sea level subsequent to 19h7 9 a por- tion of the extracted ground water was obtained from aquifers in the seaward ex- tension of the San Pedro formation. Furthermore, the observed depression in the 2-1U6 piezometric surface in this area indicates that transmissibility of the aquifers was inadequate to meet the pumping demands by underflow from Santa Paula Basin, the probable principal source of recharge. It is also possible that a portion of the supply to the aquifers may have come from perennial change in ground water storage in the outcrop areas of the San Pedro formation. Any of these occurren- ces would tend to decrease the estimated safe ground water yield of the subunit. The estimated safe water supply available to meet requirements in the Mound Subunit is composed of the safe ground water yield of about 8,800 acre-feet per season, plus imports from Santa Paula and Oxnard Forebay Subunits of about 2,700 acre-feet per season, or a total of approximately 11,^00 acre-feet per sea- son. Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits . The sources of water supply for these subunits are Santa Clara River water and direct preci- pitation that percolate in Oxnard Forebay Basin, subsurface inflow to Oxnard Fore- bay Basin from Santa Paula Basin, and subsurface inflow from the Calleguas-Conejo Hydrologic Unit to Oxnard Plain and Pleasant Valley Basins. In addition, water is imported to Oxnard Plain Basin from Santa Paula Basin. The total safe yield of these supplies, other than the import from Santa Paula Basin, was estimated to be about 26,700 acre-feet per season. It has been stated that troughs formed in the piezometric surfaces in the Oxnard aquifer in Oxnard Plain Basin and in the Fox Canyon aquifer in Pleas- ant Valley Basin during the drought period, thus creating conditions conducive to sea-water intrusion. Furthermore, the mineral characteristics of ground water ex- tracted from the Oxnard aquifer in the vicinity of Port Hueneme indicated that sea water had actually advanced inland to a portion of the aquifer then being pumped. Therefore, the second of the three criteria listed previously for determination of safe ground water yield was violated. 2-1U7 The occurrence of a trough in the piezoraetric surface of a confined aquifer is a function of the rate of pumping from the aquifer, the transmissibil- ity of the aquifer, and the hydraulic head available in the forebay supplying the aquifer. With data available, it was not possible to determine independently the transmissibility of either the Oxnard or Fox Canyon aquifers. Since transmissi- bility is a function of the cross-sectional area and permeability of an aquifer, which factors are probably subject to little variance in a confined aquifer, it was assumed that transmissibility in the Oxnard and Fox Canyon aquifers would re- main constant under various piezometric slopes and rates of pumping draft. Rela- tionships between water level elevations in Oxnard Forebay Basin, rates of pump- ing draft from the Oxnard aquifer, and slopes in the piezometric surface in the Oxnard aquifer were ^ ■'■ablished. Using these relationships it was determined that, with the present pattern and rate of pumping from the Oxnard aquifer, the ground water level at well number 2N/22W-23H3 in Oxnard Forebay Basin must be maintained at or above 60 feet above sea level in order to maintain a seaward gradient in the piezometric surface in the Oxnard aquifer, and to prevent forma- tion of a trough therein. This would limit ground water storage depletion in Ox- nard Forebay Basin to about 20,000 acre-feet, as compared to the actual storage depletion of about 109,5>00 acre-feet which prevailed in the fall of 195>1» Analyses were made for the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins to determine the maximum average seasonal ground water extractions that could have been made therefrom ever the base period without causing forma- tion of a trough in the piezometric surface in the Oxnard aquifer and thereby creating conditions conducive to sea-water intrusion. It was assumed that Ox- nard Forebay Basin would have been full at the beginning of the drought period, and that supplies available for extraction would have been ground water in stor- age in the basin, together with surface and subsurface inflow retained therein, plus subsurface inflow to Pleasant Valley and Oxnard Plain Basins from the 2-lh8 Calleguas-Conejo Hydrologic Unit. Consideration was not given to the item of "undifferentiated supply from other sources" shown in Table 15. By a trial and error method involving monthly analyses of water supply and disposal, it was determined that a maximum of about 26,700 acre-feet of water per season could have been extracted from the three basins throughout the drought period. With this reduced pumpage, ground water storage in Oxnard Forebay Basin would have been depleted by about 87,000 acre-feet, and a seaward gradient would have been main- tained in the piezometric surface in the Oxnard aquifer throughout the drought period. It was assumed, furthermore, that under these conditions a trough would not have formed in the piezometric surface in the Fox Canyon aquifer. Total safe yield of the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins, therefore, was estimated to be about 26,700 acre-feet per season, and was assumed to be equal to total safe yield of the corresponding subunits. Of this amount, about ii,700 acre-feet per season represents subsurface inflow from the Calleguas-Conejo Hydrologic Unit, and the remainder is comprised of supply from the Santa Clara River system. It should be noted that possible subsurface outflow to the ocean through the Fox Canyon aquifer could not be evaluated, and was not considered in the fore- going analysis. The amount of such outflow would reduce the estimate of safe yield accordingly. An item of water supply which would appear to increase the estimate of safe yield of the three subunits is that portion of the aforementioned "undiffer- entiated supply from other sources" which is comprised of inflow from fresh water stored in seaward extensions of the Oxnard and Fox Canyon aquifers. However, for purposes of the present studies this supply was not considered to be safe yield. Although the volume of this storage may be of considerable magnitude, and extrac- tions therefrom during drought periods may be replaced by subsurface flow from Oxnard Forebay Basin during wet periods, utility of the storage appears to be 2-1U9 limited by the two canyons incised in the ocean- floor near Port Hueneme and Point Mugu, Experience during the recent drought period showed that utilization of tti&- storage resulted in the intrusion of sea water from Hueneme Canyon to a portion of the Oxnard aquifer then being pumped. That portion of the "undifferentiated supply from other sources" possible contributed to the Oxnard and Fox Canyon aquifers by percolation of direct rain- fall and of the unconsumed portion of applied water would correspondingly increase the estimated safe yield. Since the magnitude of this possible supply could not be determined with data available, and since there are even uncertainties regard- ing its actual occurrence, it was not given consideration in the evaluation of safe yield of the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins. Table 2$ summarizes the derivation of safe yield of the three basins* The values given are average seasonal values for the drought period from 19hk-h5 through 19£0-£l # The value for consumptive use of precipitation in Oxnard Forebay Basin was based on analyses described in Chapter HI, and includes consumptive use of water by phreatophytes. The item for subsurface outflow includes only that in the Oxnard aquifer, and as mentioned does not include possible outflow in the Fox Canyon aquifer. The indicated total safe yield of 26,700 acre-feet per season in- cludes about li,100 acre-feet per season exported to the Hound Subunit and to the Calleguas-Conejo Hydrologic Unit. 2-150 TAELE 25 ESTIMATED &1FE SEASONAL YIELD OF OXNARD FOREBAY, OXNARD PLAIN, AND PLEASANT VALLEY BASINS Item : Acre-feet" Items tending to increase yield Surface inflow 1*8,300 Subsurface inflow From Santa Paula Basin 7,200 From Calleguas-Conejo Hydrologic Unit U,700 Precipitation on Oxnard Forebay Basin 5,300 Ground water storage depletion in 12,700 Oxnard Forebay Basin Subtotal to be added 78,200 Items tending to decrease yield Surface outflow 28,800 Subsurface outflow 15,900 Consumptive use of precipitation in 6,800 Oxnard Forebay Basin Subtotal to be subtracted 51,500 SAFE YIELD 26,700 If extractions of water from Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins were limited to the estimated safe yield of 26,700 acre-feet per season, and ground water storage depletion in Oxnard Forebay Basin was limited to 87,000 acre-feet, there would be increases in surface outflow in the Santa Clara River to the ocean and in subsurface outflow through the Oxnard aquifer. This increased outflow would result from maintenance of higher ground water levels in Oxnard Forebay Basin. Such higher levels would decrease ground water storage ca- pacity available for storing percolating waters of the Santa Clara River, thereby increasing surface outflow, and would also increase the slope of the piezometric surface in the Oxnard aquifer to the ocean, thereby increasing the rate of subsur- face outflow* Table 26 presents a comparison of estimated outflow from the Santa Clara River Hydrologic Unit during the base period and under present operating 2-151 conditions, with such outflow if the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins had been operated in accordance with their estimated safe yield of 26,700 acre-feet per season. The comparison does not consider possible subsurface outflow in the Fox Canyon aquifer, TABLE 26 ESTIMATED SEASONAL OUTFLOW FROM SANTA CLARA RIVER HYDROLCGIC UNIT DURING BASE PERIOD, WITH PRESENT METHOD OF OPERATION, AND WITH OXNARD FOREBAY, OXNARD PLAIN, AND PLEASANT VALLEY BASINS OPERATED IN ACCORDANCE WITH THEIR SAFE YIELD (In acre-feet) Season Surface outflow Present operation Safe yield operation Increase Subsurface outflow* Present : Safe yield : operation : operation : Increase 1936-37 160,200 160,200 1937-38 1*35,600 1*61*, 700 29,100 1938-39 53,600 66,100 12,500 1939-1*0 27,000 27,000 191*0-1*1 687,600 802,1*00 111*, 800 191*1-1*2 70,800 87,1*00 16,600 191*2-1*3 379,000 1*30,700 51,700 19l*3-l*U 299,^00 353,1*00 53,900 19l*l*-l*5 69,900 77,600 7,700 191*5-1*6 59,300 70,600 11,300 191*64*7 1*3,900 53,500 9,600 191*7-1*8 191*8-1*9 191*9-50 1950-51 Average 152,1*00 172,900 20,500 for base period, 1936-37 through 1950-51 Average 261*, 200 299,000 31*, 800 for wet period, 1936-37 through 191*3-1*1* Average 2l*,700 28,800 1*,100 for drought period, 19l*l*-l*5 through 1950-51 12,000 21,600 23,600 23,100 23,500 23,800 23,1*00 23,500 23,500 9,200 8,800 3,600 1,000 11*, 700 21,800 6,600 12,000 21,600 23,600 23,100 23,500 23,800 23,1*00 23,500 23,500 23,1*00 23,500 20, 200 12,000 6,600 2,100 19,100 21,800 15,900 11*, 200 11*, 700 16,600 11,000 6,600 2,100 1*,300 9,300 * From Oxnard aquifer only. 2-152 It should be mentioned that of the estimated 26,700 acre-foot safe sea- sonal yield of the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, it ,was assumed that about 2,£00 acre-feet would be exported for use in the Mound Sub- unit, and about 1,600 acre-feet for use in the West Las Posas Subunit of the Calleguas-Conejo Hydrologic Unit, which practices actually prevailed during the drought period. It was further assumed that some £00 acre-feet per season would be imported from Santa Paula Basin during a drought period for use in the Oxnard Plain Subunit. Thus, the safe water supply available to meet requirements in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits during a drought period would be the estimated safe ground water yield therein, less the exports to the Mound Subunit and the Calleguas-Conejo Hydrologic Unit, plus the import from Santa Paula Basin, or about 23,100 acre-feet per season. It was estimated that during a mean period of water supply and climate the exports and imports would change to about 3 y 200 and 700 acre-feet per season, respectively, and that the safe water supply available to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits would increase to about 21;, 200 acre-feet per season. Calleguas-Conejo Hydrologic Unit Since ground water is the primary source of water supply in the Calleguas- Conejo Hydrologic Unit, safe ground water yield therein was taken as equal to safe yield of the unit. As described previously in this chapter, Simi, East and West Las Posas, and Tierra Rejada Basins are experiencing perennial lowering of ground water levels, indicating a violation of the first of the three cited criteria governing determination of safe ground water yield. It is possible, also, that this perennial lowering is resulting in a condition of adverse salt balance, there- by violating the second of the criteria. Furthermore, in Conejo and Tierra Rejada Basins, prevailing low-yielding water-bearing formations and irregularities in the fracture systems in the volcanic rocks have precluded extensive utilization of ground water storage, and it appears that these basins are presently being utilized 2-153 to about the maximum practicable extent. Based on these considerations, safe ground water yield in the Calleguas-Conejo Hydrologic Unit was taken as equal to the average seasonal ground water replenishment during the base period, estimated to have been about 22,600 acre-feet. Table 27 presents the estimated safe ground water yield of each of the subunits in the Calleguas-Conejo Hydrologic Unit, The value shown for the East and West Las Posas Subunits does not include some 1,100 acre-feet of water per season imported from Oxnard Plain Basin. TABLE 27 ESTIMATED SAFE SEASONAL HELD OF PRESENTLY DEVELOPED WATER SUPPLY IN CALLEGUAS-CONEJO HYDROLOGIC UNIT Subunit : Acre-feet Simi 6,100 East and West Las Posas 10,800 Conejo 2,600 Tierra Rejada 500 Santa Rosa 2,600 TOTAL 22,600 Simi Subunit . The derivation of the estimate of safe seasonal yield of Simi Basin is shown in Table 28. The values shown are average seasonal quantities over the base period from 1936-37 through 1950-51. The item for surface inflow does not include an average quantity of about 1,1*00 acre-feet of water per season imported from Ta^o Canyon, a small ground water basin northeast of Simi Basin, The item for consumptive use of precipitation was based on the results of analyses described in Chapter III, and includes consumptive use of ground water by phreato- phytes . 2-15U TABLE 28 ESTIMATED SAFE SEASONAL YIELD OF SMI GROUND WATER BASIN Item Acre-feet Items tending to increase yield Surface inflow Direct precipitation on ground water basin 3,900 13,300 Subtotal to be added 17,200 Items tending to decrease yield Surface outflow 1,100 Subsurface outflow 100 Consumptive use of precipitation 11,300 Subtotal to be subtracted 12, £00 SAFE YIELD it, 700 In addition to the estimated It, 700 acre-foot safe yield of Simi Basin, importation of ground water from Tapo Canyon averaged about l,it00 acre-feet per season during the base period. It was assumed that this amount represents the safe yield of this minor basin. Thus, the safe water supply available to meet re- quirements in the Simi Subunit was estimated to total about 6,100 acre-feet per season. East and West Las Posas Subunits . The average seasonal ground water re- plenishment of East and West Las Posas Basins during the base period, which re- plenishment was taken as equal to the safe yield therein, was evaluated as a dif- ferential in solution of the equation of hydrologic equilibrium. Seasonal con- sumptive use of applied water was estimated to have averaged about 16,900 acre-feet. Importation of water from Oxnard Plain Basin in the average amount of approximately 1,100 acre-feet per season served to meet a portion of this consumptive use. The average seasonal decrement in ground water storage, which also served to meet a 2-l# portion of the consumptive use, was estimated to have been about 5,000 acre-feet, Ety subtracting the sum of the estimated seasonal decrement in ground water storage and seasonal importation from the estimated seasonal consumptive use of applied water, net ground TTater replenishment was estimated to have averaged about 10,800 acre-feet per season. The safe water supply available to meet requirements in the East and T 7est Las Posas Subunits was estimated to be approximately 11,900 acre- feet per season, comprised of the foregoing safe ground water yield of about 10,800 acre-feet per season, plus the importation from Oxnard Plain Basin of some 1,100 acre-feet per season. Cone jo Subunit . Since available data were insufficient to permit quan- titative evaluation of the items of water supply and disposal in the Cone jo Sub- unit during the base period, and since it appears that water requirements of the present water service area therein are being satisfied by natural replenishment of the Cone jo ground water basin, safe yield of the subunit was taken as equal to the | estimated average seasonal net extraction of ground water during the base period, or about 2,600 acre-feet per season. Tierra Rejada Subunit , A few ground water level measurements available in Tierra Rejada Basin since 1930 indicate that disposal of ground water from the basin has probably exceeded replenishment thereof. It was estimated that benefi- cial use of ground water extracted from the basin during the base period averaged about 1,000 acre-feet per season, of which some £00 acre-feet represented consump- tive use of applied water within the subunit, and the remaining £00 acre-feet rep- resented an exportation to the Santa Rosa Subunit, Replenishment of Tierra Rejada Basin is largely from percolation of the unconsumed portion of direct precipitatior Since precipitation averages less than Ik inches of depth per season over the h»39C acres in the subunit, it is believed that the average seasonal net replenishment of the basin could be no more than about £00 acre-feet. This amount was taken as the safe seasonal yield of the Tierra Rejada Subunit. Santa Rosa Subunit * For reasons cited in the case of the Conejo Subunit, safe yield of the Santa Rosa Subunit was taken as equal to the average seasonal net extraction of ground water therein during the base period, estimated to have been about 2,600 aere»feet« The safe water supply available to meet requirements in the Santa Rosa Subunit is comprised of this safe ground water yield plus the im- portation from Tierra Rejada Subunit in the amount of about £00 acre-feet per sea- son, or a total of approximately 3,100 acre-feet per season. Mallbu Hydrologic Unit The present water service area in the Malibu Hydrologic Unit, comprising less than 500 acres of irrigated and suburban lands, obtains its water supply by pumping ground vrater occurring primarily in fractured volcanic rocks* The water- using developments are largely in Hidden and Russell Valleys. Since it appears that present water requirements are being satisfied by natural replenishment, safe ground water yield in the Malibu Hydrologic Unit was taken as equal to the average seasonal consumptive use of applied water therein during the base period, estimated to have been about 800 acre-feet • 2-157 CHAPTER III. WATER UTILIZATION AND REQUIREMENTS The nature and magnitude of water utilization and requirements in Ventura County, both at the present time and under probable ultimate conditions of development, are considered in this chapter. In connection with the dis- cussion, the following terms are used as defined: Water Utilization — This term is used in a broad sense to include all employments of water by nature or man, whether consumptive or non-consumptive, as well as irrecoverable losses of water incidental to such employnent, and is synonymous with the term "water use". Demands for Water — Those factors pertaining to specific rates, times, and places of delivery of water, losses of water, quality of water, etc., imposed by the control, development, and use of the water for beneficial purposes. Water Requirement — The amount of water needed to provide for all beneficial uses of water and for irrecoverable losses incidental to such uses. As utilized in this bulletin, the term refers only to consumptive uses of applied water and attendant irrecoverable losses. Supplemental Water Requirement — The water requirement over and above the sum of safe ground water yield and safe surface water yield. 1 Consumptive Use of Water — This refers to water consumed by vegetative growth in transpiration and building of plant tissue, and to ivater evaporated from adja- cent soil, from water surfaces, and from foliage. It also refers to water similarly consumed and evaporated by urban and nonvegetative types of land use. Applied Water — The water delivered to a farmer's headgate in the case of irri- gation use, or to an individual's meter in the case of urban use, or its equivalent. It does not include direct precipitation. Effective Precipitation — This refers to that portion of direct precipitation which is consumptively used and which does not run off or percolate to ground water. 3-1 Irrigation Efficiency — This refers to the ratio of consumptive use of applied ■water to the total amount of applied water, and is commonly expressed as a percentage. Ultimate — This refers to conditions after an unspecified but long period of years in the future when land use and water supply development will be at a maximum and essentially stabilized. (It is realized that any present forecasts of the nature and extent of such ultimate development, and resultant water utilization, are inherently subject to possible large errors in detail and appreciable error in the aggregate. However, such forecasts, when based upon best available data and present judgment, are of value in establishing long- range objectives for development of water resources. They are so used herein, with full knowledge that their re-evaluation after the experience of a period of years may result in considerable revision. ) Present water requirements in Ventura County were determined by application of appropriate unit use of water factors to the present pattern of land use, from estimates of ground water extractions, and from estimated and measured diversions from surface streams to agricultural and urban entities. Probable ultimate water requirements were estimated from consideration of the probable ultimate pattern of land use and appropriate unit use of water factors. In determining the present and probable ultimate water requirements of Ventura County, due consideration was given to those natural features of the County, such as topography, geology, and soils, as they affect the use and re-use of water. As indicated by the foregoing definition, supplemental water require- ments were estimated as the differences between derived values of safe yield and water requirements under present and probable ultimate conditions of development. Certain possible non- consumptive requirements for water in Ventura County, such as those for hydroelectric power generation, flood control, 3-2 conservation of fish and wildlife, recreation, etc., may be of varying signi- ficance in the final design of works to meet supplemental consumptive require- ments for water in the County. In most instances, the magnitudes of such non-consumptive requirements are relatively indeterminate, and dependent upon allocations made in design after consideration of factors of economics. For these reasons, water requirements for hydroelectric power generation, flood control, conservation of fish and wildlife, and recreation were considered to be outside the scope of the present investigation and are not evaluated in this bulletin. Water utilization and requirements are considered and evaluated in this chapter under the general headings: "Present Mater Supply Development", "Land Use", "Unit Use of Mater", "Water Requirements", "Demands for Mater", and "Supplemental V/ater Requirements". Present Mater Supply Development As stated previously, the seasonal and cyclic vagaries of stream flow in Ventura County have precluded the dependency on unregulated surface v/ater as a firm source of water supply. The resulting extensive utilization of ground water storage has enabled the County to achieve its present stage of develop- ment. Mith the exception of Matilija Dam and Reservoir, constructed in 19h& by the Ventura County Flood Control District on lAatilija Creek, a tributary of the Ventura River, and of a few relatively minor additional surface storage developments, the entire regulation of the natural water supply of Ventura County is obtained from ground water storage. Irrigated and urban lands are primarily served by pumped wells draw- ing from underlying ground water basins. The results of a County-wide canvass of wells conducted during the investigation indicated that there were in excess of 1,35>0 wells of heavy draft, equipped with pumps having motors of five 3-3 horsepower or greater, supplying water to meet irrigation requirements within the County. There were also in excess oi" l£0 wells of heavy draft supplying water for urban and suburban uses. The irrigation wells are generally indivi- dually owned, although there are many mutual water companies in the County that obtain their water from a single well or a series of wells and distribute the water on a share basis. In 19$!, there were 92 mutual water companies in Ventura County, serving water for domestic and irrigation purposes to shareholders and members. Approximately 23*000 acres of irrigated land and more than £,000 service con- nections in various portions of the County were served with water by these mutual water companies. At the same time there were four municipally owned public utilities supplying water to approximately 11,100 service connections, and seven county water districts with about 2,000 service connections. In addition, there were nine privately owned utilities supplying both domestic and irrigation water to in excess of 5*000 service connections. Utilization of surface water in Ventura County is limited to a rela- tively few users along the Ventura and Santa Clara Rivers and their tributaries. Along the Santa Clara River, these users divert either the uncontrolled surface flow of Piru, oespe, and Santa Paula Creeks or the effluent discharge from ground water storage at the lower limits of Eastern, Piru, Fillmore, and Santa Paula Basins. Since water supplies from these sources are not dependable in quantity, and in some years are accustomed to diminish completely, many lands supplied therefrom are also equipped to pump supplemental water from ground water storage. On the Ventura River, the City of Ventura is the largest user of surface water. The City has constructed a submerged concrete diversion iveir to bedrock, almost completely across the Ventura River channel immediately down- stream from the mouth of Coyote Creek near Foster Park. V/hen available, Ventura 3-1* River is diverted by gravity into the city system. When necessary, the City o.f Ventura also pumps ground water in Upper Ventura River Basin from a well field located a short distance upstream from the diversion weir. In 19kl , vfoen water supplies from these sources became insufficient to meet its requirements, the City pumped supplemental water from a well drilled in Mound Basin near the beach in the southeasterly portion of the City. Subsequently in Wb$j three additional wells were constructed in this vicinity and were utilized until the wet season 195>l-£2. Upstream from the City's Foster Park diversion weir, there are several gravity diversions supplying water to agricultural and minor urban entities adjacent to the river. Mr. Harold Conkling, Consulting Engineer, in his report entitled "Safe Yield - Matilija Reservoir", May, 19U8, estimated that about £00 acres of land above Meiners Oaks were so served. During wet periods, there are some minor surface diversions effected below the Foster Park weir. Table 29 lists the major diversions of surface water in Ventura County, their sources of water supply, the general location of lands served, the points of diversion, the estimated present average seasonal diversions, and the principal use of the diverted supplies. 3-5 Z O 3 UJ :> z on <* CM J S3 ^ 10 O Cv- — I 0) 10 o> tO 0/1 I- k. ~ co oi u k. > to oi • - V) >-u o a. 5-0 .— oi -t- > to c u 01 o to to 0) — • c 0) o Q. a 3 3 o CO o CO 3 aj 8 Oi) Q/l an u an j — * k. c tv. o a k_ k- k. | k. o a k. j w k- 0> k» k. L. b k- V "- • •—4 o *- M ■— ■ a- • r «-^ u> -- »C\ XI 0> Q o O o o o o O IS o o c— CD co «o (Ol n t— * LA u V to -3- o X) 3 0> > cc to w. 3 6 V > CO to k» u CO 3 8.S to 0) •- z; > ^ IM Jf M tu cc 0) 0) 0) V 0) k. CO k. k. u k> u u 3 0) 4- 3 3 a C k. k. to (1) ■ a*. • » tu > a 0. C Oil O C to s a s £ -5 e o (0 to u +- > Oi ~s k- k_ s an tu a ■— to CO C3 k. k. So •*- (0 k. *—« U k. on 3 , k- ID- »_ C (0 Ola—- k. 0» o -1- i-^ ■> k. 10 +- CD 4) 3 O e? tu c_ O • — •D k- O Oil ~a k- i o c > co +- £ >» ka +- to 5 ■»- k. u k. • aa to CO CDO • — o 3 5 U. DC CO k. CO u C3 -f- s to a e o o to Ofl o s CM O o> OI D CO a. s CO 09 k. to d a. k- -(- 01 Q/l C > co J5 — tO -D CO 3 ^: tu o k. C X) o !3 9 2 — . to k_ 4) k. 01 o tut- to to to -33 01 lU 0> 3 a. CO 3 S3 a. to • tu > 5 to to o to c »o CO •D !l o) a ■*- s to o j» o 26 A3 •- — -t- u to an to — +• i_ C k. CO ■— CO 01 ■s »- CO k. b- O T^E 2 to ■»- O cc .0 — CO £ to >» ?» •a o a • L. o o a> x: c o t- i3 k. O (0 to an u -^ ti_ • 0> c C k- — o cO C s .= ro -♦— •♦- oi o to •TJ 3 • an— • a .0 3 Z -* ^ >- c k» 3 S CO .TJ 3 CO CO — 01 k. 2 an to c_ T3 0) 10 to 0) o a. OI - OI a. Ck. Cv. C C »- o 3u _* O. > ■*- > ■•- > O o CO o tw O i0 E CO .0 o k. XI *- o £> +- • ■*- C c to (0 01 (0 .3 .0 to 0) CO o c 3 2 c — ••- » (0 4- c k. • .0 O o OI — — t. 10 01 01 2 oi a/i o OI 01 CO CO ■f- ^ 01 — — i 0) o — Oil o e an • J; .« ■•— c u. - T3 -♦- ■« •«* . _■ "O 3 >- k. k. ^ -^ -♦— s ■- e o/i E to a ft oi .o co CU ■+- k. ■♦- (0 ^ k. •»- 0) u tu tu sr s: s: *^ -kmX) < — < anu. JO < c z z CO ■o ■-a k. 5 •*- a> ••- 1 5 01 > -*- o | —4 5 1 oe ;tj ■o _Q 0. 3 k w 3 c ,2 s CO co CO CO k- -»- +m *• •^ C XI 3 6 tmm •^ 3 co CO s 01 +- c 5 CO pal —4 ro ka c r> B 3 3 CO — 4 o 0) X) 01 3 10 a a U- > u_ 3 3 La a. +■ a. Cw O CO CO o — o T3 T5 k. E co s t0 k. k_ 0) >* 3 3 ■— 4 -♦- ■*- >. .0 .T3 Q. -t- k. k> — * s -3 c -♦— c C a 3 >0 X X 3 t_> a. a. CL. CO CO ^o U o o 01 > cc co k. CO CJ CO -»- g to CO > k. . — . 4) >. to s.^s (_l-i- o C0 k. k. CO (J 0>w ■»- on to ■♦- C •O k- to 0) -t- 0) t- to k_ Q. C Q CO ka XI tu a CJ c •«a ,0 on > c 1 a u_ on- c a>- c 3 3 3 to e c o U to ■ X on+- c • aa -1- k. J< u C > O a o ■Q-O o 3 ka O ffl 3 X >^ >.-»- X) -a u CO St • On ro ■_ 3 ■*- >n c .0 tu s: > „ u_ ^ O la ■ — >- o > aa k. u 01 t/l C_ 01 c oe +- re C -^ OI — E aa| 0J k, -f- £ 3 cr tu i c "3 c i— « cu tu ♦■ ■ — n >- 3 4)+- u. C TO tu if 1 tu ka <(- CI k. 0"0 Q. il 0) -t- k> n E E o -t- ka to ^A Jj u x> 3-6 Matilija Dam is a concrete arch structure with an overpour spillway, 163 feet in height above stream bed, creating a reservoir with storage capacity of about 7,000 acre-feet. The dry seasons that followed the completion of Matilija Dam in 1948 rendered the reservoir virtually ineffective in providing water to meet the then current water supply deficiencies in the Ventura Hydro- logic Unit. It was not until January, 1952, that Matilija Reservoir first filled and spilled. During 1952, about 3,200 acre-feet of water from the reser- voir were delivered through a pipe line with a 12-inch terminal diameter and spread on grounds constructed by the Ventura County Flood Control District in Ojai Basin. In addition, about 3,700 acre-feet of the stored water were re- leased in that year directly down the Ventura River, for diversion by the City of Ventura and other users and for replenishment of Upper Ventura River Basin. A minor amount of water from Matilija Reservoir was delivered directly to users in Ojai Basin for irrigation purposes. In addition to Matilija Dam, there are nine other impounding struc- tures in Ventura County which, because of their height or reservoir, storage capacity, are considered "dams" under the provisions of the State Water Code pertaining to safety of dams. By definition in the code, any such structure across a natural drainage channel that is greater than 25 feet in height or capable of storing more than 50 acre-feet of water is considered a dam, except- ing that such structures that are less than six feet in height regardless of storage capacity, and structures that are not capable of storing 15 acre-feet of water regardless of height, are not considered dams and are exempt from State jurisdiction. Table 30 presents a list of eight of the dams in Ventura County which were within the jurisdiction of the State of California as of 1953, and which were utilized for stream flow regulation, together with pertinent informa- tion for each. Two other dams in the County, under jurisdiction of the State of California but not listed in Table 30, are utilized to impound wastes from oil field operations. 3-7 z LU £ 5 Ul a! to CC o > CC IXI to z: 0. V +- O +- k. .0 ■*- Q <0 s U ._ k- k. 41 O •+- O 4> to *- o -C e +- c Qfl O - k. "O 41 u_ 41 X 03 a L. •♦- tO s O T3 O O CM ON ■o c co -g ,0 — 0-+- •- CO O Qfl i'S s: — ITS in o CM X. ID at k. j«: (») 0) 0) c k. 5 c> >. 1- I *- c 5 aj qj 5 ■+- e o i0j£ c a co —. o peg? 5 4> O Q.X3 V. k. 41 C 41 U k ijtl CO Oil 10 ca CM 4) k. k. O k. 4) *■• CC a CJ U O — B >.— k- tO .0 +■ o -Q O •— k. k_ v_ 00 o & -3- o CM WN. 4> ,H| a) "a co +- +- c «1 41.3 U 4) u_ t_ x: k. k. o .c -t- UJD* c u k. SiSS O k. .a O .0 in u ion o o •♦-Ok. c - to ii CO -•- D 4> (0 — +- C -O 41 5 .o k. C_> k. o 4) 4) LO JC _. a; o 41 k. >>.* O k- 4) .0 4) o +- k. tw 3 o C a 5 - 10 k- C u 1— < i— I r. x o u -♦-Ok. c « ■ .j eo +-3 4) (0 >- C "O O .0 _ UkU 4) 4> 4) «J 1 c 3 o CD s: T3 _ C •— D ■H O «} QC sr s oc 3-8 TO k. C 4> «3 ■»- .3 s* — O +- •-» Cv> •♦- >« O/l 10 — 5 & CM J- o CO ir> a> ON CJN o CO o^ o CTN to CM r— IT* 4) w. 4) 4) O o o a> -♦- :>. ^ X E (0 4) s .cj -t- — i ■f- — o 5 T3 5> CO -»- c o c o § OX> I/) 3 v- 3 k. H O 3 o c .—4 O +- O -»- cc ■ — » — • C_) CO <« o o c U C 3 k. C.J a. oC o -t- o -•- s £>. c e +- a -. co 10 u o IDU u >^ • k. o ^S — ■*- k. — k. •— (0 g o CO k. U. Q > u. o Q CJ o _J tj to _J LjJ 2 T3 — O k. o O o CJ 3 k. i o 4) 4> £Z JT pH o tO LU c co CO 4) cc o c :o IS vt -1 _l LU CO ON ■5 k. CO s: c CO an CU 4) an .0 to Artificial regulation of surface waters of the Santa Clara River system is provided by their diversion to and percolation in the Piru and Saticoy spreading grounds, constructed by the Santa Clara Y/ater Conservation District and now operated by the United Water Conservation District. Excess flows are diverted from Piru Creek to the Piru spreading grounds, located immediately south of the town of Piru, through an unlined ditch having a capacity of about 7S> second- feet. V/ater is diverted from the Santa Clara River to the Saticoy spreading grounds, located about one mile southeast of the town of Saticoy on the southeast side of the river, through an unlined ditch with a capacity of about lli£ second-feet. During the wet season of 195>l-!?2, about 11,000 acre-feet of water were diverted and percolated in the Piru spreading grounds. During the same season, about 25>,liOO acre-feet were similarly percolated in the Saticoy spreading grounds. As mentioned previously, spreading grounds were formerly operated by the Santa Clara Water Conservation District near the City of Santa Paula, wherein surface flow in Santa Paula Creek was spread. Operation of the Santa Paula spreading grounds was abandoned subsequent to the season of 19U0-1|1 because of prevailing high ground water levels in Santa Paula Basin. Measured seasonal diversions to the three spreading grounds during the base period are shown in Table 31. 3-9 TABLE 31 MEASURED DIVERSIONS OF SURFACE FLOS TO SPREADING GROUNDS IN SANTA CLARA RIVER HYDROLOGIC UNIT, DURING BASE PERIOD (In acre-feet) Santa Paula spreading grounds Season Piru spreading grounds Saticoy spreading grounds : Totals 1936-37 1937-38 1938-39 1939-UO 19U0-I4I 19U1-U2 19U2-U3 19h3-hh I9hk-k$ 19U5-U6 191*6-1*7 19U7-U8 191*8-1*9 191*9-50 1950-51 TOTALS 8,191 6,661* 6,768 5,103 20,137 13,652 13,51*5 16,790 5,672 3,226 8,912 396 1,956 U,738 7,067 10,01*5 1,318 1,81*0 3,780 17,21*3 22,758 7,80U 5,530 9,700 68,589 13k, 21*9 3,121 3l,U52 750 21,066 1,889 22,202 900 22,793 1,306 7,371* 3,226 1,956 13,650 2l*,310 32,803 9,122 7,370 13,1*80 7,966 210,801* Land Use As a first step in estimating the water requirements of Ventura County, survey determinations were made of the nature and extent of present land use as related to water utilization. Similarly, the probable nature and extent of ultimate land use were forecast on the basis of land classification and habitable area survey data, which segregated lands of the County in accordance with their suitability for irrigated agriculture and possible development to urban and suburban types of land use. 3-10 P ast and Present Patterns of Land Use In connection with the preparation of State Water ^Resources Board Bulletin No. 2, a detailed land use survey was conducted throughout the southerly developed portion of Ventura County during the season of 19U9-50. During 195>0-5>1, a resurvey was made in connection with the present investiga- tion to ascertain changes in land use subsequent to the original survey. It was determined that such changes were minor. The 19k9-%0 survey, therefore, was adopted as representative of present conditions of development in Ventura County. In the 19^9-5>0 survey, the entire area shown on Plate 3 » entitled "Hydrologic Units" was field mapped, and from the resulting maps the areal extent of each class and type of land use, including both those requiring water service and native vegetation and other types not requiring water service, was determined. A determination was also made of the areal extent of each class and type of land use overlying the major ground water basins. In agricultural areas, results of the survey were reduced by the estimated percentages of non- productive land, such as county and state highways, farm access roads, and lotsj and the net irrigated area of each crop was estimated. Similarly^ the gross areas of various types of urban development were determined add were then reduced by appropriate percentages of streets and walks, etc., to obtain the net water-using area. Table 32 summarizes, by hydrologic unit and subunit, the nature and extent of lands in Ventura County presently requiring water service. The areal extent of urban and irrigated lands in Ventura County during ±9h9~50 is delineated on Plates 2U-A, 2^-B, and 2I4-C, entitled "Present and Probable Ultimate Land Use". Table 33 presents a summary of present land use in the four hydrologic units, indicating the location of various classes of land use with respect to the major ground water basins. 3-11 3 S < § CO cc cc LU O cc ■o > X c — O C II - 3 CC CO 3 > U1 X > o — _|CC k. — 5 5 5 1 > CO k_ w CD o a > a.-- 3 QC ■3 5 uS CD X) a 3 Q.CO CD 3 ■o c '.J CD a. c "- 00 — NOCM ic\cooo-3-vOLAfA — •• fC\ — . KACM K\-* > o oo j-so LA— « LA ' o|lao cm — > nNltx o> 1-3- nO O CM O O LA ON 00 vO CM ^m — . CO -O — • IM I — CO CM -* CM vO CM — < fA c\j rAO O vO -3- LA- ICO ~« — tA (3 CT> -WO — OCMaO'-vOO — OlON O O -3- o ,>T\ — CM -3 K> J* ICO f- CM -• 1-3 — •fft O IA O O O C0l-3 LA — CM O sO 5 cr -o co OnO O On — " O O O OnnO LA — CM N> .3- ^ (AKNfA^o -3- — . o — • -3- cm lV -3 O LALA -3"— < —. ~- LA — I LTvO rA CO ONONsO CO -» £A O O KN.CM J-IOCOOvl N IM ■* fAli— olf— m I- P 3 ■ jsoimcnoo oko cNla (M p p o>ooo^oooo fS°]S CO on CM to LU m c_> co k. W CO co s» u 6 CC LU CO CM C c3 co "D X) k_ co oc k- X) C — 3 XI 3 V) |ated area roads i gated are ■.0 a) a 0) O -1- D O -^ O (J _l •■*.«• ^» .-M CO — W— O O "O OH-fr- .TJ CO <4_ 3 -*- CO O CO c 2 C C — -t- c D O TJ (0 t. "D ■*-■*- 9 cc X) k. «1 E CD k- (0 e co w x o "D CO C o k. c CO * •■* ** «-• *** 10 (0 .— ~0 in CO D •— (0 ■< T3 c c c c u w n n O W k- — ■+- CO 10 T3 n O X >» CO CO LU 5 u ai a> a) L. ♦■ u -t- -•- CO +- > k. -•- -f- o a> u. k. 3 CO c k_ ■+- •+- o OC TJ'OTJ'O s o o k. c/) co e xi x: ■» > — X> XI k. kj k. a/ u_ •" t CO 3 (J -t- D >• v- v. CO >0 X) k» a at oj a> a> o cc cc os or u C u co CO a •- — C 3 — uj -»- _| S i-> CO < > CO k_ k. < (U — k. »- 1) CD s _> 2 4~ CO CO o cc 3-12 Z3 O u < cc 3 i 5 +- 00 ■ c UJ 10 o CC a> o < k- O Ul co C\J o Y\ 1 — t c :> UJ a: «w erf to < CC UJ to 0. CO -»- o JO D C >s CO 4) — CO — • c ,TJ_ 5 QJ (0 XI -. > D 0. to c — co to 5 c — XI x a. D O tO X> cc — St- G. co co -3 c to X O 3 O Lt- to 55 O X) £ 3 to (0 3 CO — °-S 10 XI +- 3 C to to a> k. +- o — 515 .— XI •- 3 u_ to 25 urn XI a. 3 1/1 c+- k. C CO o J to -) UJ Ul 4) CO 3 T> C to 00 N"\ !■*-.-< C- LT\ LTiCJN— < -=»•-=*■ F- on im cm lt\ if* rc» 00 UN CM 00 -*u"\ " UN_=J-OCM_d-C\l_3-fr\ vOvOOO— il/NO J-N- . KN. cn _ r~- on KN, CM O sO OOCMOOK\0 OlON O O LT. — • CO roko -* ^- nn, o cm cm — • lt> —\ir* •— onnn, iriuy ■=t —• — 1lt\ cm — < lo - SPl c -« CM ^ o —• J — On UNION f>0?- CM O CM — < C0lff\ F>- f— O\0»0 |l/VQ0|-3- —« cj cm — r— («o . |f*- CM O un r— I*- in oo ol-* r»- un co >o >o i I s - CM rCN — < OI^J- fC\ — CM CM UN — « — " *->jsO ON — • — OJOOM"-UMI) Ol— • r»- LfN CO >C >0 O^ICM O ON r*- CM r~- CM rCN — < OI^J- fO\— CM CM UN -=l|uN CO CM -* -h . — i[-jD On — • —> UNI 2* r T\ O CM CO J-vO LPvvO —luN O O O O — < CM| ^t~* ao cm j- -< —l-a - — %o ool |CM | -3- o w\ iajo>o N\ — • — CO 00 J* — < UN xO •** f*" OC0O-*f»-CM0NO — |0D O — • O vO — • CM J- ~« CM — . — 10 O =r&c5l$ ■T co trvcM -a - 00 CM CM CvllCM UNI^- UMAN |r-CMlCT\ — CM lo -*| St CM |00 |00 i~- C0 3 o C0I^OCMf^-CMf~-CTN i>r»>o vo so vo oo -a - MtA O rfN 00 N"N 00 CMlO^ Jir- — • — cm l»« colco \ _* U"\ I 1 — N0 j-cm|k>lHco •hOOXIMvCI J^D LT\Cj|gN— coi<\-3-j-0'-ho Mo o ctn — o cm o k\ cm -. if\N cm Moo o — ir\ CM I J- O oon j-oocoiao foloo o oo cm o r>- ir N- — -^ CMIIO cm — < l^-LTNO —LT>PNr--t~-CM J- .3- ITN CM nO f 1 - CM to ITvCM ON UN KN^O CJN f--0^CC7N-HC7>00 CO(00 Lfr fC\ CO ~* tC\ LT\ ICO O ICM o UN|^^^ O oooooooo ojo o o o o o o|o UNOJ-OnOOOO oIun oo|n> -=f vo ir> Uo a c >. CO H- X) k. XI 3 c JD co D CO CO CO TJ CO C .-* CO CD a> a an-t- co e CD to CO CO D CU k. Qfl c to co — < co c c CO 0) CO CO CO CD CC CC CCO ai i- CO -I- — < (0 o o o X) -C c o •-t to CO CO CU HcO o co ro v. XI >> D k. XI ■*- D — ■ CO ■ 3 O X) ^5 c c CO CO XI •* i: CJ D CO o CO "•- +- — co a> • k. co a; • — > CO — Q _J TO CO 2& x> CO -o (0 — +- > k. H — o ' T3 C3- XI k. 3 - j u. < : -o c (0 XI !0 I C I CO i ' c . <1J J3 CO a/ li- re CO TJ CO CO ■OT3-I- a> co to -t- o OJ) co i Q/l k. — -o k. co an k. co 3 — co co o "a >« co co k. D<0 c k. +- -*- o 3 -OD^COCOCUCOCOk. •+- co — k. o c ctz mu C0-*-CJ-»-3C0?^k. k. BJ 3 CO •— k-cocoD -*- CLZQOI-COIZ 10 or UJ o UJ cr LU UJ DC (_) Ul CC en uJ o to CC o 3-13 cu 3 C C o c_> UJ 8 UJ u > ce t/1 QC 1 i (0 V. 1 -»- o o — u. w C TJ 3 •O >. — X O co — . -♦- — • oj o — . o i— as — • •• « •• o 3 a/> 3 25 2: tj £ 10 (0 ■*- JO 3 C/1 8 -t- ae; •- c 3 *- -D 555 i/i .. .. CO .TJ — »-♦— CD — -*5 -.00 c >- 3 3 •- 1/1 a> — — V— OJ O " •• O k. •♦- a 0- -» — • c X 4) D C Q O O 3 -OiO u g.. .. c_> 1 -»- (0 — .0 c 3 a> .J 3 — 1 C/1 — > •+• ,3 io a_ .. .. -t- c %2 _l 3 W1 -t- 1/1 10 i0 'TJ UJ CO O Q. - •■ +_ e 3 — -O CO 3 l/l .. ~ .. co co 3 TJ c CO —• b_ CU a >. -»- TJ C CO to (0 lO o -o cm it\ cm lt> ooIcjn r>- u> -=r cm cm o p-. «> 00 CD o p* ^oeoocotM^of ON — . CM .=r — ■ fCNJO LA Cvj _* CM — • O -=r O O O >Olf*- O O O LT> O Lf'4'*— K «>. cmIkn. cmKo 00 JJ-tPi^- O — • CJNATV (*- cm j- f>- f-~ *n fC\ -^1— O O O On CM oolo cmIcm -a- — < — • n"\ unIco .r\ 0000000 Ho o o o f— o oli*- jo - O K"N f "O XI 40 CO CO 10 t> cu CU 0) X. £ cr cc (0 • 3 CO > Q. 3 4- »- J2 6^3 10 O -t- 3 CO — CO — U CJ X) Urn. 3 ■t- CO (O s 3 O TJ •0 1- X) C a s >-*-+- CO to I- X c E -0 C C co i\3 CU CU c U1 k - (0 -2 CU •> ft TJ t_ 1—4 — -< JD 1 1 x> c 3 CO CO j; >- CO CU CO • mm • — 3 >*■- -a to (/I O k. i- -t- -t— O CD CO (O 4) •»- 01 — c CU i_ e 3 w — . X) -Q »- i_ c O to • -• — C 3 — CO -♦— c_> « CO Q _l z: ^ 1/1 •< > in OCNJLfN— J-— OUT>_ c\ijr-j3-o-=^'*r\j ' j- a r-r " K-\ CO K> -3 _-4 fO . f^- — • Jt-NOvOO OlO"> C0|' v - CM J- CNJ KA iKA— IlTv cm \tr\ \k\ OCM»OCJ^CMJ^iCNJC\JO 1^ IM K"» CM 0> ON On 1 — ao ffs CJVnO O — < U-N KNO^CTnK^J^OCM — . Lf^. U""> — < Ioj colo 1LO I^O {hoocAOirvwo ON CM CM — < 4M O nO LfN O O LfNIN. ^m sO UN O — t CO — • CM CM OS 1 "— Nj - cm|on /n |u CM . "ft! . KN f- cm — < un. r— u*>no -^V^- coIun — • — < in- .3- co I j- — -Kp — < K\ O — ICM — .INS J" -T |CM J.M CM 0>OnO 0«N.f--NN.O OlUN. OlUA f\i r\i u-\ — 00 o loo cmIo cm o CO ^* a ft NO tf UJ c/1 ac [0 •xl - -* CO CO 3 & CO TJ O CO 0) Z TJ TJ -t- 0) cO CO or -t- O Off c CO 1 3 cut »- o> ra — TJ k- UJ k. ts.- CC CO an 3 CO < CU ID >» CO CO UJ ^ 3 CO c u +- •+- cc 3 T> 3 v 10 CO CO CU 4) »- < +- CO — (J c to 2 CO O 10 -»- U -t- 3 .0 >v ^. w c^ .0 3 CU TJ C o a CO a TJ TJ CU (0 Qfl CU k. a/i . r- o ul '_> 3< Q Z3 2 I— -a: 2 _ljg t— z B to LU QC Q_ >- cc to 0) o — _J aa s-s >tO Q. > <0 3 -*X) O 3 CO CO — >+- o — .5 (U XI a 3 .g.to o o o o o o O LfNCM CO NA _3-NN,0n*O vO O CO ON o o o o p o J--. CO -d-l 51 - NN. CM —. .# CO o -3- o o CM o • * «% (—4 NO g co res ON o o o o o o J"^ LT» ON — i CO CTn .3- o o o o o o —> cm vo cm vo >r\— < o kma O o ON ON i*-\ rc\ i/ncm rr\ CM o o o o o o J- CO J-LTvCO -* 00 UA UfNlJN O ON ON o o o o o o -3- tfN. CO — 1 CM NOO-< o o o O ON ON •* n -3- » ft LfNtX\ CM CM s o o o o o w- CM h- O LT\ COMMN-- CM •— -. 3 o o o o o o o —< CO >o •— o o o o o o ol NO LTv r-« fT\ I o ON CD u '> la V in 10 b. c CU +- 1 CO 3 lA CCl 3 on O CO l_ C — ' V. co Z. 13 cm .TJ •— u- "O 3 S o CO T3 3 JN-O lw ^-* t- oj a) k. X C k. to o w- e CD a CJ 3 ■♦- CO k- o — • CO OJ u X) CO — ii -+— O D > o >»+- v. V) ■+- to r-* !- k. cox .0 0, L. O Q Z M Ji 0> > o o o o o o o -=rLfNir\ -• co r- (M |n- o -t- CO v- x c 14- x a co D o ~. en CO cu i- — - D x >- C ►— Z 2 ^■^ •*• — 3 CO s CJ O 01 i*° w 3 < co gS l*\ o o c if\ 2 1- ■* Z ttl -I UJ erf 2» < »— s to 1 li- o >• ITS X) 0) k. o ■»- ■L. ■.— ^5 roS c to X a si co o co to St k- X) CO S c to 5:5 O 03 z: o 3 -+- ■ ■ — X 8 vo!-o ■»- D s k/1 •"I - •• a -i- o. ■ — E 5 — ^ 5 — j u_ m 35 to 2 5 CO X) UJ CO o o o o o o K^ J" NO o o o o ol cm — . en ^t cnj .=«- Cfk -• CO -«| » » * » >o o j-oo o o o o -* NAvO ON r~- t»-\ f5 c\i ft' O QO O O O ~ i?Sen^ O CM ctn>o go en $ o en T o 00 CM O o o o o o o k\ en o o r- oo into-* I KM r- ^ f*- o o o o o o £ & o o «a -• — o o o o o o o o » -. ^ q r~ 00 C\» On •?> 00 O O O O O O £ o o a o o o K\ ^3- -& O &*. O i-C\ SO K> lT> O O p O O O J3- CJ> L?N . M -^ 00 '00 tTN-^ >0 P*- o o o ' CM to o o o o o o — . cm >o cm — . O O O O O O -O tntCM*- ^T ~* co 00 -=r — *-> m at * c\i — • cc\ o o o O (M J- lA O m CO ,M N\ tO o o o o o o o La r— nr\ j-^- rr\ & >o cn-=f -* — j* — • tr> CO ir\ CM cm _=r O O O o o o| tr\^o -3-O^pO nS o CM l/N — • ~> 1 >D o o o o o Ol o o o o o o tr>— • ^*>o t\ en— « ct»k> j- p o o o o ol I s - O >o O f*- — ■ — < N\ — . o o o o 00 o o co C\J CVJ co k. V- c CD •♦- V •♦- CO CO 5 a a 3 <0 5 CO XI 3 CO Q» O CO u 3 CO tvi o to h> C — «- C — k- V - — < Q/l Q/ .2 a. on ■♦- t- (0 O w (0 g — u_ T3 — u. T3 b_ ttJ ,0 ci X tr "o co O crn 5 o ■o 0) C 10 0> k- fa x: cu o T3 k- (0 ^_ CD CJ .- (0 CO X <0-^ iD 10' to «3 C o (0 X) D >»"Ou- r— • CO T3 3 2.T3 u- — • 5! —■ ft) n tl Vli tl r t »- o e X) a ro d (0 U- CD (D k. XT C k* <0 o — tv +• O k. £ X) Q. CD D •^ i— (5 — i- o -< CO o CD k. O — < CO o o Q/ > vTJ 4) *• ■♦- k. » S-t ■*- »— c (0 u. t_ > CD CD V. X) CO CD k- x> CO 0) — cu +- cu ^ -o CO — CD +- V 3 > O M >>+■ t (/I4- c O > ■+- k- CO -•- to w t igr a(D O O Z Q. 3» 3» k. k. COX 13 CD k. (5 1 a: O Q z a. * J* > o 3-16 o to H- — « 5 u •—I o o _l o ^— s ae TJ a 5 >- C 1— Z Z *— ^ -*- 3 w C O ti a LU C_> k. u l/l o 3 j: 03 tc\ Q 5 c K\ 2 i— 5 v- > X u 3 CUI X) O03 ■— — ■♦- -. o — IB v. C s: x> 5 5- to TO •+- o +- jO D i/) 03 V) -♦- O ■ — ^S 03 X) -•- 3 S* 00 co T3 03 — .+- CJ3 x o o t_> CO O 0) -»- c — o C <_> (O 3 t ro .a «1 J 3 as i75 D -t- O/ tO ■/> 4> 4> -< 3 (0 —" O 03 a. o -^ . c to 3 TO XI _) D co +- 10 (0 TO 03 Ld (0 o Q. •« •» ■*- s X) D cO ._ E CO U. 03 C — i 03 u — o o o o o o CO nO f"*- 00 *"0 ~-* ir\tx\ k-\ KA — • cm o Tp CM Q o o o o o -*o>so -3-k*\o o o OJ — 1 CM 1^ _ C7N O — ~£> — — cm oo LT\ LfN LTN o o CNJ _3" D O O O Ol 3- —l 0> CM tr»>o o o o o o ol J" 00 CM PC\ o CO — i o o o o o o C\J J-ff\ o o o o o o ^O cm ov rc\ cm — • O O r— o s o o o o o ol o ONCM 00 r- lf\ I — • -3-CTN -3- — . -. CM o vO CM 00 to O O o on KN. O ON o p o o o o r- f- cm o o o o o o o o CJN O o ON o o o o o o o o o o o o o CTvfTX J-—. CM CT^M O O O O O O ■*0 "NO r- aj r-- O O CT> vO »o — O O O O O o LP\ o> o »o o CO 0NI*« CM J- o o o o o O O O CM O fTN o o CO -3- « * «^ CM O O •-I i>r\ n J- -3- CM o o o o o o 00 K"\ .O — « I s - -< — -TO CM CM >0 hT\ o o o o o o o f>- CM — -3- J- o o LTt « CM O ON O 03 3 3 a* o c — Z to CTT3 Q. TO D O — • to > TO 0) k- — a>-t- oj *• w (0 -t- ojx; TO 03 za.3] X) to mora tr-o 4) c W. TO . TO X) 4j 4) k. e j .5 k_ 03 to u. CO o >«- 10 4) 4) (J •*- (0 2>"D t4_ x: c t- Q. TO D O — (0 TO 4) k. 4) -I- o to XI 3-17 During the course of the investigation of the water resources of Ventura County conducted by the State between 1927 and 1932 and culminating in Division of V/ater Resources Bulletin Wo. Ij6, similar land use surveys were made. For comparative purposes, Table 3U presents the results of a survey of irrigated crops made in 1931-32 together with those of the 19i;9-5>0 survey, tabu- lated by the three major hydrologic units. It should be noted that the values presented in Table 3k represent gross areas and include roads, farm lots, and other nonproductive lands. 3-18 O CO EH M •^ B o M O o o t-1 US O 1 Pt Os Q_cf /*~N -ct >H On to ra 33 H 0) a O § o cd PQ •^ <«! ■< 4 c Eh ,ri cm — ^ S 1 M H ra co os £ H en c_> Hi EH 3 o n-P CD -H £3 O 1 o ra -H oj to P o bOrH cd o 4 -p o o us. Os -■31 Os H Q> -P n S 05 CO O I OS Os rH •P •H q as ■p &o q o CD H > O o us Os rH £ £ o o COOOIANHON^) H O raOsOsOsO-Ct/OUS -dCMsO-^fraUsHco CM HcO H UNco US. -=t ra c>- C\j oo c\i us o nn r— csj o H r— ra -4 so I ra j^tJO\j os i us C\l OS US Os o- H CSJ CSJ H CSJ co n^O H C^-CO US. H vO HlAJJnH\An ra cm r— CM _cf O rH C-- OnH-4 ra cm H c— -ejeo -d SO I OCMUSUSUSCO » rH I t>- H rHO rsvO I I ^ ^ #s r> r* | sO CM JH sO usco-dr---crrH-d-H , >0 onwoonomao cosQ ra H CM ra Os [>- CM OS car- O ra ra CM OCMsOcMUSOH-d- csmnjhhw^o i H CM _3;cO O- HI CM Os CO CO CM o sO 3 sO us CM ra CM On ra CO CM o co -=r O Os rasO _rj- ra Os OJ • ra-d" OsO so H 1 ~=i o 1 _^CO US UN O iH 1 us r\ | #\ r\ »> ri »x | «\ US US 0\NHH o H H H CM CO US H CO US SO CM us -d- sO ra -3- H -=f us us ra H OS CM ra sO r-i so H •4 1 o sO p W q Eh •H •^I ra a u M to Ed W 2 c£ aS CD n o XJ s H tH £ •p 2 w a *h H 2 -d P ^i CO ra cd CO C rf -P q •p. ^ q q w CO f the nature and extent of the probable ultimate pattern of land use as' related to water utilization. A land classification survey was made to ascertain the suitability of lands for irrigated agriculture. In addition,, a habitable area survey was conducted to determine the extent of lands not suitable for irri- gated agriculture, but susceptible to urban types of development. The objective of the land classification survey was to delineate the lands suitable for irrigation development and the probable crop pattern that would result with such development. The classification of lands gave consi- deration to such factors as topography, soils, crop adaptability, and ease of irrigation. It did not consider those economic factors relating to production and marketing, which are variable among given areas and subject to considerable fluctuation over I a period of years. The survey encompassed the entire County, and included presently irrigated lands. However, it did not include those 4reas now devoted to concentrated urban type developments, nor the inaccessible rugged mountainous terrain in the northerly portion of the County, most of which lies within the Los Padres National Forest. Table 35 presents the standards utilized in the land classification survey. 3-21 tO CO a IB a> — tO — 4iX 5 to o a. o_ < a. § o < "to h- e/> CO >*"0 _T 5TS \T\ o c — • H\ OJ »— an— « UI < .— i d u 2JE «s U. J_ »— ►— 1 -T> UI OH UI < k d k o z >* X u 1 x i 10 i £ T3 M •— 4- C ■o ■ .0 l k V o OJ -»- 'i^r — * CO X) 4- 4- to ^J ■ 4) C <0 ari V HI Q tO e e — k u a> u J *- k ■ — O — k 1 5 o c Si? c O 41 4- ^ O k. o i 3 ol to| u x 4> i 10 r (0 (0 1 — ■o C iw — • OJ to CO o C — O 3 TJ '0 0> CO £ 10 111 k CO 41 — • C 41 *- • o 04- e j- 4) co to - k 41 — . X CO »M — a.— c - C O O k CO 4- — • 4; ■*- 41 S Qfl-Q — 4- C CO k Q.4- e — a> a> c X 4- ^ to 41 • k. Q/1 X C "O 0> -t- C X o 25 o t> «_. a > 41 • • o Q/I 41 0/ k. 41 — k w CO •— 4>- — Q/I— « C k k o> to <_- _J o o u co a-c — k. ._ (0 -f- — CO 4- •f- CO 4- CO 4) 3 C O 41 Q. 41 C >» to i y ij (_. C 41 "O — 10 Q. CD k. - CJ — i 414- E O • «0 — k T> CJ > k. c T) c — Q. c 3 rr> co - o o o» e to 41 >. co -o ctj +■ U 41 _- p CO CO 4- 2 k. 10 — ■ CJ — O CO — o CJ 4-4-9 ■4- ^» an .. co c ■*- (0 ■♦- 4i e >■ co — o — o o (/) to k — 01 C -. ♦• k. » c a c c >. — X CO k 41 E Q/I co 4- 4) a. c k Q.4- X 4- — k_ 41 41 «— Q. OJ1-- 41 > E 4- CJ .. 41 — 41 >. c 3 CO — — • 01 k. Qfl c 0) Ol C QJIO CO 10 C X) 41 "CM CO to co -4- a> -•- CO 41 (0 .__ 5H- U U k, to , a/i c c —4 4i o o ■»- iii: 4) 41 •♦- H +- e o eg o — • (0 K J. -■ 3 _ _: iO (0 a* — • kr Ck — k. B 25 u C O 41 k. X - c a *H2 (0 k. >0 J- 1 i?^^ o c/) — to «)+• no k. (0 41 a-*- • c c LfN 41 — to <0 41 — IC-S-S ._ O CO fp Qd4- _. a D — 41 CO T3 CO k- || = O 41 O — Q/I co 10 r.£5 -4- E O 4- — O C C E 4) — IO CJ E 41 a. ai O (J c\j c an a c o> - T3 CO (0 —J o> — k- o cj to — CO -4- 1 O k (J k. (0 0) -8^a k- c CO 41 4/ C Q/I J_ ~ "(0 u c 4-TJ k. an co 4- IE '" it 4- CO 4) — >v D CO 4- CJ o> o Ik >v > X — • 4> C -I co a • o o » U l\) § CHT3 41 j-~ C O U — k- C Sx S CO an 4- 1 c C s to k « 0) u Q. o £ _* 4- c ■ — * an 1 k_ a> o k. to s •a Q. to -. 4- CO c CU *- sO ^- co an O 4- 1 o CO u _ 4- § £1 oT — eg k_ Q. T3 Fo o 41 3 T3 4) k. C to N — . vO D to k. ■ — a on CD Q/I CO X Q. 41 CJ C O CU e (0 OA MX In k k. to 3 4- u '3 C X c 41 ■"* x 1 to 0) u o Q/I >« a o o k 1 cx c u 1/1 CO to 5. CO Q. 41 41 D w O CO u_ 4> — O O t_, 4- 8 - ■o (0 41 "O k "fi^ 4) — 4- >. p (0 4-0 0) > X •D — 4- O 4- — E ^"D 41 — O k I O CO 41 -c a x cj e iO ■- — E X .. Sn 41 CO (0 »- Ol — iO — — > 41—4- o an x E X O iO 41 -S2 ■4- 10 • x to 2 • ■/I >• o> a s —-4 —4 • M 3 4- a* X an — • — ] as t/- ( ,1 X O 4- tO a oi an TI c 41 _2 > k — o >« 4- 3 X to CJ a 4) 41 41 CO a. U_ 41 CO k o u_ k J8 9' 41 ti_ 5 to o Q 4> k St? c O 1— § D E O E 4- •- O c • — » X c rji X U CO J- o o k k. to o an c tO _<: a. 88 k k u 41 10 3 O o O c CO k Q co to a o 3-22 UI - .£ 'c ■ _c % • CO (0 "O l/M 41 .CO "x k o- u •— tw 2. "0 41 o o CT ■ ■ — • CO 41 Ol 01 41 k (J 01 — < to CJ Xk X . 5> • CO -f-lw a>-»- E 4-Q. *"0 tC 041 CO 01 CO k CO c CO 8f X CO 4> COX t041 41 — iO c 4- O. to — •> Q. k 3 to CO CO*- (0 o o — k tOC 41 "O -8S O k — • CO— < E (0 — o> O CO k 4-k+- — '__ co 041 CO r co-. a. i— a e a. u co o CO CD to 4- c co _- Irrigable valley floor lands of Ventura County are primarily found on alluvial deposits, and generally are of excellent quality. These alluvial soils have been derived from sediments that have undergone little or no change or internal modifications since their deposition, and are still in the process of formation. They are comprised of deposition washed from areas of sand, sand- stone, conglomerate, basic igneous rocks, old valley filling deposits, and other rocks within the drainage basins. Adequate depth of soil is present throughout the areal extent of these lands. The topography is smooth and level or gently sloping, and is suitable for most types of irrigation practice. Soil textures vary from medium to heavy, with good water-holding capacity, and the soil struc- ture permits easy penetration of roots, air, and water. Irrigable valley floor lands generally are suitable for continuous production of all climatically adapted irrigated crops. Irrigable hill lands include those lands which fail to meet the requirements for irrigable valley floor lands in regard to topography, but which are suitable for the production of certain irrigated crops with special irriga- tion practices. Since these lands are characterized by steep or rolling topography, care must be exercised in their irrigation, and terracing and/or permanent cover crops may be required. Some of these lands are to be found on recent alluvial soils, but for the most part they are comprised of residual soils or old valley filling and coastal plain soil groups that occur in marine or stream terraces. Depths of the soil varies from deep to the minimum allow- able, and the underlying material may either be rock, a poorly consolidated material, or a heavy compacted soil with local tendencies toward hardpan. Sur- face soils are principally medium in texture with a structure pezmiitting ease of penetration of plant roots and water. Irrigable hill lands are primarily suited for crops such as orchard or permanent pasture, which can be irrigated with small heads of water, and cultivated or harvested under adverse topogra- phical conditions. Row crops can be grown on these lands where topography 3-23 permits, but extreme care must be exercised when irrigating in order to prevent erosion. Although the development, irrigation, cultivation, and harvesting of crops on these lands will be more difficult than on valley floor lands, they are well suited for crops easily damaged by frost, such as citrus and avocados, in that good air drainage is provided by their topographic characteristics. Lands which failed to meet the minimum requirements for irrigated agriculture in one or more of the characteristics of soil, topography, or drainage were designated "non-irrigable lands", and were considered unsuitable for irrigation development. These lands include the rugged mountainous areas in the northerly portion of the County, river wash, coastal beach and dune sands, and saline tidal marshes. Certain minor areas located in isolated portions of the County, although meeting the standards for irrigability, were not so classi- fied and were included in the non-irrigable classification. The term "habitable area", as used herein, refers to those presently undeveloped lands not considered irrigable, but which, by virtue of their topo- graphic characteristics and proximity to either present urban centers or probable future urban areas, were considered susceptible to urban types of development. From the results of a survey conducted throughout the four hydro- logic units of Ventura County in 1951-52, it was determined that there were about 6,300 acres of non-irrigable lands which could be considered habitable under this definition. Results of both the land classification and habitable area surveys indicate that in the four hydrologic units there are about 235*000 acres out of a total area of about 557,000 acres susceptible to concentrated and intensive water-using developments. Plates 2I4-A, 2I4-B, and 2i|-C, entitled "Present and Probable Ultimate Land Use", shows the areal extent of these lands. Table 36 presents the results of the land classification and habitable area surveys conducted in the four hydrologic units. 3-2L CD J* ■o C CO Q 10 ~ I» — > -O - — ■ Q.— XI a) «) lO O C Qi) CO CO CO - D ♦• O o o o o o **0 00 CTs— * oooooooo o — .irNj-cM^vo- • CM I — LA CM I 4DvOvO J3- J- LA — • J - fO o o o o o o — • 00 sO N^O^IO O -a-— I ctnn-no O CM J- 00 -3- co la la — « cm N^ O CM LP O CM LA LA O O O O O CM lAJ-vO CO N~\ — < 0D C^O> OOOOOOOO o^ -d- a> as -=r oo cmcm J-j3-ONK>C\J— xO CM o o o o o o o CTNt>TM — LA-« •— " CJ^LA^A O LAO CM 00 CM ^O CM J*KO (•ACM — • o 1/1 o o _l o cc o > >• t— s? X § co i?S 2: CO —1 i. UJ _l to <; ca CD §5 ■* c »— c_> to O CD -t- <0 CO CO ■*- o +- ■s to +- ro c c co CD C0-O CO X) c 4) 1- fe CO cu -o — 1 c XI— CO (3 1- —• i- u -.— CO XI I -. ro cxi x o co z or cox; XI Oft co c on— co - O.T3 v. o c w. — . ca HI co c CO — ■ an — 1 cox 3 an ro c . an — to - a-'O k- o c -• (0 — . CO > - o oooooooo — • (■«->© la la o> -=»■ o- IAC0 .-3-vO CM CT\C0 r— 000OO0—J-— A 00 -*CM CM 0000 olo oooooooo hA CM 00000 olo 0000 CM ONvO I s - O LA J-xO 0000000 olo -=rcMN~\— 1 -« la -j|o o f*- laco NNtr> OOOOOO co(\ia>j-coir — < -3-— < Jd-LAP— O vO CM o la 00 0000 I — nO vO ^A 1 -. « ~ p. I — « CM _*— • x» 00000 CTvvO CM 00 O lap- cm no co — ' CM OOOOOOOO or^-pr\r---j-vOLA-J CM CM n- CM 00 J3 00000 o,_ >a -*00 LACO Ol— • CO 00 CM nO ->0 CO i« «t «t ik ^r^oo J-f>- DlO Ol d|— cm| o ^c^ -•■O ON j3-LTk J- J-L/N-^-— • LAvO O KNCTNa^C^. OOOOO OlO O O CM — ' CM CHO LA j3" N"\ LA>0 JlON «% «k «% ^ *| * CO LA LA— —|CM Ol o —I CM i 2? CO CO > > cc cc V- C0 >s CO CO CO CO CO > CO ~> CO CO :o k- ■— CO • — xi c — 1 co 01 CO CO X) CO D D ~4 cc CO CO — CO — c CO - — ' • ^ -t- +- co PM« k- co > co o_ a. — « CO CO (0 c c -t— CO D -< +• u O CO ■*- > -f- co c v. o_ ■D TJ ci xi CO co co cc +- j XI »— CO k. i- >- D CJ CO e co -a k. i. co D D — • fc. CO D O k. CO .— CO CO u to -f- D — • -1- c co co co 1/) an— H P- CD k- ■¥■ LO 3 1— D a O a 3 c C0 10 k. — c 3 c c co CO E C0 CO L, CO C O — CO Xi ^% S •i- co - CO X X — < CD CO =3_jac cuau.io£oocL —1 to UJ 3 C_> H- LO —* > CO CO C_) CO 2: XI CO XI k- D an CO "O c co c 10 XI CO % c an 'Lo co "O CO T3 C on CD — X) V. k_ c — CO XI —4 k. CO 3+- ■0 -h- -1- CO co +■ k. c -*- CU c CO CO CO w c Cl a> CJ ae 3-25 ! i . ' _ i i It is probable that lands in the four hydrologic units of Ventura County which were not considered either irrigable or habitable, totaling about 322,000 acres, will require water service to some small degree; 'Although these lands are largely of a rugged topographic character, it was forecast that scattered residences would be found therein under conditions of ultimate devel- opment. It was considered that water service to these entities would not be obtained from an organized agency, but rather would be obtained locally from springs or shallow wells through individual effort, and that the effect of these relatively minor uses on the water supply of the County would be negligible. In addition to the approximately 557,000 acres of land included within the four hydrologic units, there are about 631,000 acres in Ventura County, most of which is in the northerly mountainous region. Of this remaining area, about 620,000 acres are within the boundaries of the Los Padres and Angeles National Forests. It was estimated by the United States Forest Service that there are about 300 acres of irrigable land in the Los Padres "National Forest and within the Cuyama River drainage area. In addition, it was determined that there are about 2,000 acres of irrigable land outside the national forest boundaries in the upper reaches of Piru Creek. Under conditions of ultimate development, it is probable that there also will be an increased number of sub- urban residences and resort-type settlements in the national forest preserves and in the remainder of the County area not included within the four hydrologic units • Utilizing the results of the land classification and habitable area surveys, and giving consideration to present and probable future trends of development, a pattern of probable ultimate land use was forecast for Ventura County for the purpose of estimating water requirements. As has been shown previously, utilization of water in the County at the present time is predomi- nantly for the needs of agriculture, and the urban requirement is much smaller. 3-26 |t was concluded, however, that in the future the magnitude. of the urban water requirement may approach that of irrigated agriculture.. _; This, conclusion was based upon the indicated susceptibility to urbanization of a substantial portion of the County, together with the recent and apparently continuing tremendous growth of population of the nearby Los Angeles Metropolitan Area and of Cali- fornia in general. In this connection, the current rapid change in land use in the adjacent San Fernando Valley from irrigated agriculture to urban and sub- urban types of community development points to the probability of such an occurrence in portions of Ventura County in the near future. As has been men- tioned, a trend in this direction is presently in evidence in areas adjacent to the Cities of Oxnard and Ventura. Accordingly, each hydrologic unit and subunit was studied from a standpoint of its susceptibility to future urbanization. Estimates were made of the percentage of the gross area, classified as requiring future intensive water service, that ultimately would be devoted to urban and suburban types of development. Based on these studies, it was estimated that under ultimate conditions of development in the four hydrologic units of Ventura County, nearly one-half of the lands requiring intensive water service would be used for urban and suburban purposes, with the remainder used for irrigated agriculture. A probable ultimate pattern of urban land use was then derived, based on percentage factors for the various types of urban development determined in extensive studies of the Los Angeles and San Diego Metropolitan Areas made in connection with preparation of State Water Resources Board Bulletin No. 2. For the probable ultimate irrigated area, a crop pattern was derived based on the results of the land classification survey, crop adaptability, and prevailing trends in irrigated agriculture. Table 37 presents the probable ultimate pattern of land use for each hydrologic unit and subunit in Ventura County. 3-27 o to Ul d b z Q O Z (_> •a: _l < -.5 o ►— z Z Ul a: ;> Ul Ul CD § a. O 3 C -O - 3 ^5 S-8 > to w w si _l a£ co ■ i- - 5 +- £ -Q CU 3 ;» tO k. k. Oj cu a. > n. — o 3 to o — CD X3 a. 3 Q.tO CD in 3 TJ C TO CU a «0 CO CO u oooooooo olo o olo — « »-. onltm/nco oo vo ooi— • r~- unkn. —• CM 00 O LT> -* KN. CMlo CM — .1 «3» oooooooo l~- -. CM N-\ O —. — llA o o P 3 oooooooo olo o olo KN. CM CM CM CM Lf\ ko IO Cvjl— • 1; '— |0 Ila o sOI— « ChJ--N -It-.K'N |f-_MtoJi\| oooooooo olo o CM la o o ON — i CM ?A oooooooo olo o olo 00 CO 00 op CO r*» BB * oo lArAfA ia ' o o olo o olc I LA fOlcO 00 CO - )LA CM|f OOOOOOOO p' — • CM CM CM CM OOOOOOOO on — ia o -itCM —) IA oooooooo — co cm on _ ON o o IA CO — < CM O O -- LA olo ICM olo o JiJf LA ~|(A >o - |_ LA ooooooooo sO 00 CO 00 cm ia CO CO o oooooooo o fN. cm r«- j- — ■ sO LA o cr-l^ La* ~.|la o o -* ON co on LTV LTV — > CM o o LA O — CO o O O LA CM f^- K\ IA nO CU u CU CO (U > jQ n _. k. •M> i> co a> •*• i- CO a. >0 s 1 k. CJ CU qa c x> g CU CO CJ c cB k. +- 3 — u J3 1 c co co 3 CO > CU D D 3 to x> CU -»- CU -" c •+- ii CO 3 C CO o c •t- o co a- (0 3 co-o e L. CO CO 10 u v. Jl Ql) l CU — 4 ■—• «-H K * *. io ■o L. c co o- -a k. CU > CO CO CO — * — • — « co-o S 3 9 -t- CU v. c -t- •mi 10 •—■4 ••• t3 c rv« CO CU c l ra o CU XI 10 ro 3 CO CO 3 Oj CO — 3 CO k. CO c C C C (J U t. (A i> -»- 0) CO ■D CO CU o JD — CO "D 10 CO Ql) CU CD OJ CU '— >- -*- -t- kr +- o ->- •*- o o •— •+- "O "O "O CU CU ft O CO co CD o Ql u_ co ■»- o ■*- 3 ro Ql) CO k. o •—• u i5 a Ml ■+- .^ h S 3 «- L 3 — -»- k. 1 o at: ac ae c_> u — C/> Q. U- < m J- <12QOhcIll/l s to C3 z M 3-28 I co CO +- Q -t- X) 3 to S 3 O, CO O to 3 c£ >- C 3 1- gzp~ w < O k. ■— ' < CO ^ eje 2 < a. CD s: 3 3 (0 — *■ 5 CO XI -t- 3 c to (0 k. -4- o - e c — • 3 — -X) — 3 Uu tO — X) a. 3 to £5 CO X) CO 3 UJ to T3 c CO C CO oooooooo olo o ,OIT\vph"\osO>0 UNcolo cr> offMftj-cM^JO oilo i — IfS — CM* -310N ikn. o o o o o o ctnono cm cm C\J — i CM K~\ LP. o o olo o o| on M s* •* 1 —• cr-lr- vol > 4 oooooooo olo o olo C/M^ CM LfN — < r^fT\-0 UN— « CM -31 1 "— ooooooooo ^f^fLT*^ O -3- oooooooo olo o olo — ONJirvji~-cHco CNJ vO — • -=»" vO CM UN — «[CM — « — 'iLfN ^ I-jT cmJoo oooooooo olo o olo oo ^tC\__CM K"\— • 1^— • — •IrO. CM . |.3" — <|LCN L o o o o o o vO -3-ao roc I s - RS_ _ CM *> o o olo o olo St CH—' tTN LPl— . - 12 3& oooooooo olo o olo rr, i^on — . ao I s - roico cm i/nun _ _ _ NNOn LTIuN oooooooo olo o olo sr — . — . .— Ir- cmIon fl) a; ec CC 0£ ro CD ro - OJ CO t- .0 g Oil c XI c CO c- X) 3 lb. 3 -s C +- XI CO ~i o D O CO CO ■o •2-fS CO c ■a ■a CO k- 3 C c as -t- O CD ra a C <0 -o E c •M X) •>■»•. CO T3 w ' — ' ~ < — ' CO X) C 3 co ro ro T) i- .^ (S 3 01 IT) O CJ k. o — tO Q_ U. tolrrc I s - r— — o o o o o LAC^-O C/N oooooooo m-\i*- J- oo ^r^^t CM tTc Jd-CM r^- ooooooooo J-CM nO I s - CO O -* CM — < — . — . J-vO CfJ o rr\ , co O O h- KN Lf\ I — KN N> CM l/N — CM O O CVJ —> CM O olp o O o LOJI"- -a- OJ sO oloo CO vO -3- ^ ■» Ho , — • .J- sO j- ^l- olo o o o oltf> crv CO r- — llA ON — • ~— 1 > % |k> J- — • vD oooooooo olo Olp O O O LfN ~^ \ • — i CM J- oooooooo olo o o o O O CM nO (*-— ' l/MOi r-i— , ' CM I s - j2r — r~* r— 00 CM — <||N- »o rv\ 00 J- i> k. CD CO CD +- CD £» +- a. CD CJ 01 3 to -3- CM CD U > k- 00 CM CO T3 k. (0, -f— cu 4) C ro 3: o (0 k. CO c (0 m T3 CO CD on c CO k. CD T) ■o CD ■*- "O -t- CD CO w CO k. C co -4— o CO Qfl •-• CO 3 CO CO k. 3 3 on CD i- O" CD CO o — XJ > k. 1) CD > .+— CD »- c .^ a^ k- ■ — i ■ •■» to CO CD c *- CO -t- X) CO a! 3 CD CO — O CO (0 D c CO CD O u_ i- 3 XI co 3 co CD CJ] CD i— co — < +- -k -a k. •»- o — 3 "O 3^ tn U CD CD 0) O k. CO c_ c 1— (0-1- CO — Wi o s CO CJ 2 0) k. o i- • — u_ in ■*■ o +■ 3 OJ1 CO i- Q. CO —i co o co — CD 3 - — -t- CO 1 o o •- s-s nj x) 3 i/l (0 CO 0 UJ CO o a. - XI CO 0) 5. T> C ro 10 10 •.0 ooooooooo -^•N-ON^^^^^■^3•c^J— >lo O00O JTKAJNOO ^r " O LTV -3- LA LP. LA CM CM vO O O O ON J- j- -3-r>- wS— oSj- CO P-,2 82 00 S° 9l2 o olo ooooooooo -t KA -3- LA •>*> 1£ "LAnO -O — i — i oooooooo — • fA -3 LA CO l>A LA o o o O CM -« IA KM — olo o olo LAIT-N — LA!LA —.loo "\J|— .. o o olo o o o o o o o o CM oooooooo olo o olo ro 00 00 CO O^ * IM O O iM ON -3 -3" J" — — • — 1|00 — • OS-O * I * *l " -3" fsO i\i|ON oooooooo olo o O ON CM LfN 'A. ON -3jlM fA LfN — < — • *\) -3K0 O O O O O o laco -a- o oo o — cm nn. j* oooooooo olo o olo — • -3- .3 -3- «\LA — «lc\l CM i-A|r- iT»OvOvo — « cm cm|o — coIon CO c c c cd a> co e e to U U L ID ■a I c CO X) TJ k_ CO 3 c X) la X) 3 CO •o to c D 'i rj O c k- .0 XI •O v. C 3 (0 CO O CO CO D 3 o ^ e 2: o x: »- k. c o «! a — • LO Q_ li. 10 +— CO CO W +- O O 0) k. aO00sO KN.3- — •OOC\J«3-J3-LAON— •-31J' oooooooo olo CM IO, K~\ fO\ O 00 LA rrJf*- 0 lOO vOl-3- g 2 r- an o CM o 00 oooooooo olo olo o >0 f^^ >0 ^~ LA 1-^ LAj-O 00 JX — _ OO Jf- .A CM o o o o o o LA 00 -o 00 LA 00 — . O LAt*A O O ol OOOOOOOOO LA— < LAKA LA — ON— « QN P" -3- 00 OOOOOOOO olo olo — . O LA l»» IfA CvJlLA —•00 LA IlA LAjO o CM o CM CM KN. 8 3 CO 3 O 3 -8 +- CO — k. cj CO -+- O -f- 3 .0 3 0)- u X) M 3-* CO k. c a CD 3 C ■ <0.2QUt-aHfl£ on c a co o 3 - CO > k. ■*- +- C 3D TO S "* OJ (!) > X) CO eo c 5' O CM -3- t«- LA LA o o >o |N~ CO o LA CM J- LA 3 s .3- o M sO 00 00 LA 2 ft o o o o — ON LA l<\ o o LA fA O ON o olo o P o -n -jIo ON r~- sO LA coIj- r»- r^ •-* o p o o R O ON c- NO LA as ao •— < o ON LA -3- •> st C\J r~ hA CO CM — CM CM LA O O ON — ON O iM O fA LA c/1 3-30 Unit Use of Water The second step in the evaluation of present and probable ultimate water requirements of Ventura County involved determination of appropriate units of water use for each of the classes and types of land use requiring water ser- vice. In addition, certain phases of the hydrologic analyses described in Chapter II required determination of use of water by native vegetation and other lands not requiring water service. It should be mentioned that unit values of water use presented in this bulletin are used in conjunction with net areas requiring water service. U nit Values of Consumptive Use Unit values of monthly and seasonal consumptive use of water for both irrigated crops and lands not requiring water service were estimated, utilizing a procedure suggested by Harry F. Blaney and Wayne D. Criddle of the Soil Con- servation Service, United States Department of Agriculture, in their reports entitled "A Iiethod of Estimating Water Requirements in Irrigated Areas from Climatological Data", dated December, 19hl t and "Determining Water Requirements in Irrigated Areas from Climatological Data", dated August, 1950. Use of this procedure involved correlation and adjustment of data available on unit seasonal consumptive use by irrigated crops in other localities to correspond with data and conditions prevailing in Ventura County. This included comparison and correlation of data on the basis of variations in average monthly temperatures, monthly percentages of annual daytime hours, precipitation, and length of grow- ing season. It disregarded certain generally unmeasured factors, such as wind movement and humidity. Also utilized were data and analyses appearing in a report to the Ventura County Flood Control District by the United States Depart- ment of Agriculture, Soil Conservation Service, entitled "Ground "-ater Replenishment by Penetration of Rainfall, Irrigation and Water Spreading in 3-31 Zone 3, Ventura County Flood Control District, California", and dated April, 1953. In each of the hydrologic units and subunits, seasonal consumptive use of water for each type of land use, other than urban types, was determined for climatic conditions as they prevailed during the chosen base period from 1936-37 through 1950-51. Values so determined were taken to correspond to values for the mean period. Average unit values of seasonal consumptive use were also determined for the drought period from 19kl|-li5 through 1950-51. In addition, in order to properly analyze hydrology of the ground water basins in the Santa Clara River Hydrologic Unit, it was necessary to estimate unit values of monthly consumptive use for the base period. Following is an outline of the procedure utilized in estimating unit values of seasonal consumptive use of water by lands requiring water service and native vegetation: 1. The unit value for each irrigated crop during its growing season was taken as the product of available heat and an appropriate coefficient of consumption, where: (a) the available heat was the summation of the products of the average monthly temperatures and the monthly percentages of annual day- time hours, and (b) the coefficient of consumption was one which had been selected as appropriate for this part of California by Harry F. Blaney as a result of his studies for the Soil Conservation Service. Certain modifications were made in the coefficients as a result of studies of consumptive use of water available from other areas. 2. The unit value for each irrigated crop during its non-growing season was taken as the amount of the precipitation available, but not exceeding one to two inches of depth per month, depending upon the crop. 3. The seasonal unit value for each irrigated crop was taken as the summation of values determined under items 1 and 2 for that type. 3-32 kn In general, the seasonal unit values for native vegetation were taken as equal to the available precipitation up to about 1.3 feet in depth. 5. The seasonal unit value for phreatophytes was estimated to be five feet of depth, from data appearing in Division of Water Resources Bulletin Wo. 6, and Division of water Resources Bulletin Wo. hk, "Water Losses Under Natural Conditions", dated 1933. 6. Seasonal unit values for free water surfaces were estimated from available records of evaporation at reservoirs in Santa Barbara and Los Angeles Counties. Long-term records of evaporation in Ventura County were not avail- able. 7. Seasonal unit values for remaining miscellaneous nonwater- using types of land use were estimated on the basis of available data on corresponding- consumptive uses in similar localities. 8. Seasonal unit values for urban entities were based upon detailed studies conducted in the Los Angeles and San Diego Metropolitan Areas in con- junction with the preparation of State Water Resources Board Bulletin Wo. 2. 9. Unit values of seasonal consumptive use of applied water were estimated by deducting seasonal effective precipitation from the calculated unit values of total seasonal consumptive use. Initial fall moisture deficiencies pr irrigated crops presented in Division of Water Resources Bulletin Wo. U6 were employed in this determination. 10. In the Santa Clara River Hydrologic Unit, unit values of monthly consumptive use for both lands requiring water service and native vegetation were estimated from the procedure described previously, modified to account for monthly climatic variations. Table 38 presents the estimated unit values of mean seasonal consump- tive use of water and consumptive use of applied water for irrigated lands in Ventura County. 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J Q <_) H- z 4) a. en a o a> on co V. 4> > CO 3 O .c (ft 3-36 — X 01OJ c o o (J)Xt C OJ> •J CO X c 5 UJ >- l/l I— UJ O 3 t- 12 UJ o =» (_) 2 -J '- < ^ 1 2. y- o — i Z 2 5 2 o o UJ QC (- UJ < I— s: < — i s t— CO UJ CO X) T> .— X CO 3-C 3 +- C c S CD CJ > c Q i- a: cu 3 -O o c - 0) a CO X 3 co i- — i col — . i_ O 3 k- C a> CL 5 u_ cu O OT Q.T3 >- C ►- a> -4 -. LO K> •^3 o • • o * • o 04 J* 0~> u-s o^ a-> o Lf> • o o o o LfN o —. — < IA CD J- 00 00 o -* 4 o • • o • a LT\ O — o i • • • • -. — LO • • • o (T\ KA O ,-1 — 4 LO 00 c CO t3 c 0) co ■ on- 3 4_ O 0J) — < co o to w X (1) o . T3 k. X a> Xi a. c o o CU ■*- XI > CO c • — CI) CO •1- w XI s X a. 3-37 Presented in Table Ul are estimated mean seasonal unit values of water delivery to and consumptive use of water on urban and suburban types of land use. Drought period values for urban and suburban types of land use were not estimated, since the effect of varying climatic conditions on use of water by these types was considered insignificant in Ventura County. As mentioned pre- viously, values presented in Table kl were derived from detailed studies of water use by urban types of development in the Los Angeles and San Diego Metro- politan Areas. Values for unit delivery requirements shown in Table 1*1, although probably representative of ultimate unit delivery requirements for urban types of development, appear to be greater than present deliveries in the service area of the City of Ventura and in the Rincon Subunit, in the cases of multiple residences, strip and downtown commercial, and industry of a manufacturing nature. For present conditions of development in the portions of the County where applied water was taken as the measure of water requirement, records of historical water deliveries rather than the units presented in Table i;l were utilized in estimating water requirements. However, as described hereinafter, these units were employed in estimating probable ultimate water requirements. 3-38 TABLE Ul ESTIMATED MEAN SEASONAL UNIT DELIVERY TO AND CONSUMPTIVE USE OF WATER ON URBAN AND SUBURBAN LANDS IN VENTURA COUNTY (In feet of depth) : Delivery : Consumptive use Type of land use : Applied water :Prec lipitation: Total Residential, single 2.8 1.3 0.9 2.2 Residential, multiple £.0* 0.3 0.6 0.9 Residential, estate 2.2 1.5 1.1 2.6 Residential, rural 1.8 0.8 0.8 1.6 Commercial, strip U.O* o.U 0.5 0.9 Commercial, downtown 11.0* 1.1 0.5 1.6 Industrial , manufacturing 8.5* l.U 0.6 2.0 Schools 1.1 o.U 0.7 1.1 Parks 2.2 1.7 0.9 2.6 Dairies 1.9 1.0 0.9 1.9 Livestock and poultry ranches 1.3 0.6 0.7 1.3 Industrial, extractive 0.0 0.0 0.6 0.6 Subdivided, not occupied 0.0 0.0 0.6 0.6 Airports 0.0 0.0 0.5 0.5 Vacant 0.0 0.0 0.6 0.6 Streets and roads 0.0 0.0 o.5 o.5 Not applicable under present conditions of development in service area of City of Ventura and in Rincon Subunit. Unit Values of Applied Water In certain portions of Ventura County, it was necessary to determine appropriate unit values of applied water to furnish a basis for estimating water requirements, particularly for probable ultimate conditions of development. To this end, records of water applied to representative crops available from mutual water companies, ranches, private individuals, and publications of the Division of Water Resources and other agencies were analyzed. Field studies of water applied to predominant irrigated crops were also conducted during the course of the investigation. Records of historical deliveries of water to principal urbanised areas, such as Ventura and Oxnard, were obtained and analyzed. Data 3-39 regarding delivery requirements for urban entities in the Los Angeles and San Diego Lietropolitan Areas were also employed, the results of which are shown in Table la. The results of the studies for irrigated crops indicated a definite relationship between the amount of water applied to a given crop and the amount and occurrence of rainfall in a given season. Furthermore, extreme variations were noted in the amounts of water applied to a given crop in the same season among several users. These variations resulted from difierences in irrigation practice, soil types, and individual preference and skill among irrigators, and were of such an indeterminable nature that an accurate accounting thereof was impossible. Presented in Table i}2 are estimated average unit seasonal values of application of irrigation water on principal crops in Ventura County during both the drought and wet periods. Also shown are arithmetical averages of the values for these two periods, which averages were taken as being equivalent to mean seasonal irrigation applications. VJhile it is known that many exceptions and substantial variations from the estimated values occur, they are neverthe- less considered to be representative of present irrigation practices in the County. 3-hO TABLE h2 ESTIMATED UNIT VALUES OF SEASONAL APPLICATION OF IRRIGATION WATER ON PRINCIPAL CROPS IN VENTURA COUNTI (In feet of depth) • : Average Hydrologic unit : : \ for : Average and subunit : Crop : drought for wet s Mean • period ! period Ventura Citrus 2.5 — — Santa Clara River Eastern, Piru, Citrus 2.8 2.2 2.5 Fillmore, and Santa Walnuts 1.0 .5 .8 Paula Subunit s Alfalfa 5.1* U.8 5.1 Truck 3.1 2.2 2.6 Mound, Oxnard Fore- Citrus l.k 1.3 1.1* bay, Oxnard Plain, Walnuts 1.7 1.5 1.6 and Pleasant Valley Beans 1.1* 1.2 1.3 Subunits Truck 2.0 1.2 1.6 Calleguas-Conej o Citrus 1.9 l.i* 1.6 Walnuts 1.2 .8 1.0 Alfalfa — 3.0 Beans 1.1 Truck 1.2 Substantiation of the values for applied water presented in Tables hi and U2 was obtained from the Mound, Oxnard Plain, and Pleasant Valley Subunits for the drought period from 19^U-U5 through 1950-51. Detailed studies were made to determine ground water extractions in these subunits for each season from 19UU— U5 through 1951-52. This study was conducted in cooperation with the Southern California Edison Company and included analyses of power consumption by agricultural, municipal, and other major plants pumping from ground water, pumping plant efficiencies, the results of about 580 pump tests available from the Southern California Edison Company, and of data on pumping lifts obtained from analysis of measurements of depth to ground water made during the period of 3-1*1 study by the Ventura County VJater Survey. By applying unit values of applied ■water considered representative of the drought period to determined irrigated crop acreages, and by making similar computations for urban and suburban lands, it was estimated that 102,000 acre-feet of water per season on the average were applied on the Hound, Oxnard Plain, and Pleasant Valley Subunits during the drought period. In these computations, an additional allowance was made for the use of the American Crystal Sugar Company's plant at Oxnard, which was estimated to be substantially in excess of the unit delivery factor of 8.5 feet of depth indicated in Table Ul. The average seasonal pumpage during this period cor- rected for imports to and exports from the three subunits ivas estimated to have been about 107,500 acre-feet. In view of the nature of the basic data, the check furnished was believed to be reasonably close, and the average unit values of seasonal application of water to prevailing types of land use were considered representative for the drought period in these subunits. Presented in the following tabulation are estimated present weighted average seasonal unit values of applied water in the Mound, Oxnard Plain, and Pleasant Valley Subunits for drought, wet, and mean periods: Seasonal unit values of applied water, in feet of depth Urban lands &3 Irrigated lands Weighted average for urban and irrigated lands Drought period 1.7 1.8 Wet period U.3 1.2 1.3 Mean period Wat fc3 er Requirements l-U 1.6 Estimates of present and probable ultimate water requirements in Ventura County were made by applying appropriate unit values of water use to the present and probable ultimate areas requiring water service, and by utilizing 3-1*2 historical records or estimates of water production. In portions of the County wherein water applied to lands in excess of consumptive use will either return to ground water storage and be available for re-use, or will drain from the area under consideration and be available for re-use downstream, the measure of water requirement was taken as the amount of consinnptive use of applied water. For lands overlying confined ground water basins, wherein it was assumed that water applied in excess of consumptive use is prevented from returning to ground water storage for subsequent re-use, the measure of water requirement was taken as the amount of applied water. Similarly, for other portions of the County not overlying ground water basins, wherein the unconsumed residuum of water applied either drains directly to the ocean or is discharged thereto as sewage effluent, water requirements were measured in terms of applied water. Water requirements in Ventura County were evaluated for the conditions of water supply and climate that would prevail with repetition of the base period, and also for conditions that would occur during a period of drought as that from 19hh-k$ through 195>0-3>1, under both present and probable ultimate patterns of land use. In many water resources studies, water requirements for a given stage of development are determined only for a mean period or for a base period which is considered representative of mean conditions. In Ventura County, however, and in similar areas subject to wide extremes in seasonal water supplies and climatic conditions, with particular regard to precipitation, water requirements for irrigation are substantially increased during periods of drought when the natural supply from direct rainfall is reduced. This results in a marked increase in the demand for artificial water supplies from either surface or ground water sources. Thus, for such irrigated areas, drought period water requirements are of particular significance in planning for water supply development. As stated previously, for purposes of analysis in this bulletin, it was assumed that urban and suburban water requirements are not appreciably affected by such seasonal and cyclic climatic variations. 3-1*3 Present IVater Requirements The present mean seasonal water requirement of Ventura County was esti- mated to be about 180,000 acre-feet. It was further estimated that during drought periods this requirement would increase to about 205,000 acre-feet per season. Determination of the present mean and drought period seasonal water requirements was based on the following assumptions: 1. That the nature and extent of land use in Ventura County deter- mined from the land use survey of 19U9-50 is representative of present conditions of development. 2. That average conditions of water supply and climate during the base period were representative of mean conditions, and that present average seasonal water requirements determined for base period conditions of water supply and climate are equivalent to present mean seasonal water requirements. 3. That present average seasonal water requirements estimated for conditions of water supply and climate prevailing during the period from \9hh~b$ through 1950-51 are equivalent to present seasonal water requirements during a drought period. k* That deficiencies in the estimated seasonal water requirements for both urban and suburban and irrigated lands cannot be endured. 5. That the estimated gross production of water by the City of Ventura during the season of 1950-51 of about 5*700 acre-feet represents the present seasonal water requirement of the service area of that City. 6. That the average seasonal extractions of ground water in hiound, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit, during the period from 19hh-h5 through 1950-51, corrected for exports and imports, are equivalent to the present seasonal water requirements therein during a drought period. 3-UU 7. That the average of the estimated seasonal extractions of ground water from the Mound, Oxnard Plain, and Pleasant Valley Basins for the two seasons of 19kh-h5 and 195>l-52, corrected for exports and imports, are equiva- lent to the average present seasonal water requirements therein during a wet period. 8. That the arithmetical average of the seasonal water requirements during the base period for the Mound, Oxnard Plain, and Pleasant Valley Subunits, determined under the assumptions of items 6 and 7, are equivalent to the present mean seasonal water requirements therein. In the Upper Ojai, Ojai, and Upper Ventura River Subunits of the Ventura Hydrologic Unit, wherein water applied in excess of consumptive use will either return to ground water storage and be available for re-use, or will drain to Ventura Hiver and be susceptible to capture by ground water users in Upper Ventura River Basin or surface diverters along the Ventura River, present water requirements were estimated from unit values of consumptive use of applied water. For the Lower Ventura River and Rincon Subunits, wherein excess water is drained to the ocean or discharged thereto as sewage effluent, present water requirements were estimated and assumed to be measured by total application of water. Present water requirements in the Eastern, Piru, Fillmore, Santa Paula, and Oxnard Forebay Subunits of the Santa Clara River Hydrologic Unit and in Calleguas-Conejo and Malibu Hydrologic Units, were taken equal to the esti- mated consumptive use of applied water therein, since reregulation of the unconsumed portion of applied water is obtained in prevailing free ground water basins. As mentioned previously, present water requirements for the Mound, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit were evaluated from estimates of total applied water. Table k3 presents the results of the evaluation of water utilization in the Mound, Oxnard Plain, 3-liS and Pleasant Valley Subunits during the period from 19Ui-U5> through 1951-52, which data v:ere used in determining present water requirements therein. 3-W z »* < CM _l IP. a. i o it* CC ON < — i Z _ X X °B •> o 8"i o 2: U"N J- 2: 1 t-Z J3 ^t -K O _U — . »— -f- 2o 0) or u_ u. u. 1 0) I/) w. 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(0 ft u_ en tr>tM QJ C J-tTN 5 1 1 V m j*— rj j-ir* k. 9J CT»0> u v\ — — > 4 3-U7 It should be mentioned that examination of records of irrigation application to walnuts in the Simi Subunit of the Calleguas-Conejo Hydrologic Unit indicated that during the base period insufficient water v/as applied to meet the consumptive requirement of this crop. It was estimated that about 2,900 acre-feet of irrigation water per season were actually consumed during the base period by lands planted to walnuts, as compared to an estimated consumptive requirement for irrigation water by these lands of about 5,100 acre-feet per season. Thus, the present water requirement was estimated to be about 2,200 acre-feet per season greater than actual present use in the Simi Subunit. Table kh presents the estimated present mean and drought period seasonal water requirements for each of the hydrologic units and subunits in Ventura County, as determined from the foregoing methods and assumptions. 3-S8 TABLE JUlj. ESTIMATED PRESENT MEAN AND DROUGHT PERIOD SEASONAL YIATER REQUIREMENTS IN VENTURA COUNTY (In acre- feet) Mean s Drought period Hydrologic unit : Urban and: Irrigated • : Urban and Irrigated and sub unit : suburban : agriculture : Totals : suburban agriculture : Totals Ventura Upper Ojai 100 300 Uoo 100 300 Uoo Ojai 600 2,900 3,500 600 3,000 3,600 Upper Ventura River 800 1,900 2,700 800 2,000 2,800 Lower Ventura River 1*,100 2,100 6,200 U,ioo 2,100 6,200 Rincon 200 300 500 200 300 500 Subtotals 5,800 7,500 13,300 5,800 7,700 13,500 Santa Clara River Eastern 300 300 300 300 Piru 200 7,000 7,200 200 7, UOO 7,600 Fillmore 500 13,800 1U,300 5oo 1U,700 15,200 Santa Paula 1,100 III, 600 15,700 1,100 15,700 16,800 Mound Uoo 11,100 11,500 Uoo iU,5oo 1U,900 Oxnard Forebay 300 U, 200 U,5oo 300 U,Uoo U,700 Oxnard Plain 9,700 U3,ooo 52,700 9,700 50,600 60,300 Pleasant Valley 700 25,900 26,600 700 31,600 32,300 Subtotals 12,900 119,900 132,800 12,900 139,200 152,100 3alleguas-Cone j o Sirai 600 9,100 9,700 600 10,100 10,700 East Las Posas Uoo 9iU00 9,800 Uoo 11,100 11,500 West Las Posas 100 7,000 7,100 100 8,600 8,700 Cone jo 300 2,300 2,600 300 2,900 3,200 Tierra Rejada 500 500 700 700 Santa Rosa 3,100 3,100 U,ooo U,000 Subtotals 1,1*00 31,U00 32,800 i,Uoo 37, UOO 38,800 ialibu 200 600 800 200 700 900 TOTALS* 20,300 159, Uoo 179,700 20,300 185,000 205,300 * Present water requirements for minor water service areas not included within hydrologic units were estimated to average less than 100 acre-feet per season. 3-U9 Probable Ultimate 'Tater Requirements Probable ultimate mean and drought period seasonal water requirements of Ventura County were estimated to be about 389*000 acre-feet and about h20,000 acre-feet, respectively. For the probable ultimate water service areas in the four hydrologic units, water requirements were estimated by multiplying the predicted acreages of each type of land use by appropriate unit values of seasonal water use. However, the foregoing estimates of water requirements also include allowances for expected minor water-using entities, scattered throughout the four hydrologic units and the remainder of the County, and not requiring intensive water service. In general, these minor allowances were estimated on the basis of population density-water use relationships. Require- ments for predicted minor irrigation developments were estimated in the same manner as for other probable ultimate irrigated lands. For water service areas in the Upper Ojai, Ojai, and Upper Ventura River Subunits of the Ventura Hydrologic Unit, ultimate water requirements were estimated by application of appropriate unit values of consumptive use of applied water to predicted ultimate water-using lands. For the Rincon and Lower Ventura River Subunits, unit values of applied water were utilized. In the Eastern, Piru, Fillmore, Santa Paula, and Oxnard Forebay Sub- units of the Santa Clara River Hydrologic Unit, unit values of consumptive use of applied water were employed, while unit values of applied water were used in the Mound, Oxnard Plain, and Pleasant Valley Subunits. Unit values of applied water for irrigated crops in these latter subunits were estimated by applying a 70 per cent irrigation efficiency to computed values of consumptive use of applied water. In water service areas of the Simi, East and West Las Posas, Tierra Rejada, and Santa Rosa Subunits of the Calleguas-Conejo Hydrologic Unit, ulti- mate water requirements were estimated by application of appropriate unit values 3-50 of consumptive use of applied water, increased by 2$ per cent to allow for waste from these areas necessary to maintain a favorable salt balance in ground water basins and for possible exportation of sewage effluent, which latter occurrence could result with increased urbanization. In the Conejo Subunit, ultimate water requirements were estimated by multiplying acreages of each type of land use requiring water service by respective unit values of applied water. It is believed that the utility of ground water storage in the Conejo Basin is limited by irregularities in the fracture system in the volcanic rocks from which ground water supplies are principally obtained. It is probable that with increased development of the subunit, the uncertainties attendant upon utiliza- tion of these ground water supplies will render them of minor significance in water supply utilization and regulation, and that water service will primarily be obtained from other sources. For reasons similar to those cited in the case of the Conejo Subunit, ultimate water requirements of the Malibu Hydrologic Unit were determined by multiplying acreages of each type of land use requiring water service by res- pective unit values of applied water. For those lands in the hydrologic units not requiring intensive water service under probable ultimate conditions of development, but wherein scattered residences were forecast, an ultimate mean seasonal water requirement of about 1,100 acre-feet was estimated from population density-water use relationships. For lands in the Los Padres and Angeles National Forests not included within the hydrologic units, the United States Forest Service has estimated a probable ultimate mean seasonal water requirement of approximately 900 acre-feet, inclu- ding the requirement for about 300 acres of irrigated land. Other potential water-using lands in Ventura County, not included within the federal reservation or in the four hydrologic units comprising a gross area of about 11,000 acres, including a probable ultimate net area requiring water service of about 1,700 3-51 acres in the Upper Piru Creek drainage area, v^ere estimated to have a probable ultimate mean seasonal water requirement of about 2,800 acre-feet. Table U5> summarizes by hydrologic unit and subunit the estimates of probable ultimate mean and. drought period seasonal "water requirements. 3-52 TABLE U5 ESTIMATED PROBABLE ULTIMATE WM AND DROUGHT PERIOD SEASONAL VJATEH REQUIREMENTS IN VENTURA COUNTY (In acre-feet) Hydrologic unit iviean : Dr< Duj;ht period : Urban and: Irrigated : : Urban and : Irrigated i and subunit : suburban : agriculture : Totals : suburban .agriculture : Totals Centura Upper Ojai 1,1*00 2,300 3,700 1,1*00 2,600 U,000 Oj ai 3,500 2,300 5,800 3,500 2,500 6,000 Upper Ventura River 6,100 3,900 10,000 6,100 U, 100 10,200 Loner Ventura River 111, 000 11;, 000 lli, 000 1U,000 Rincon 5,000 5,000 5,ooo 5,000 Subtotals 30,000 8,500 38,500 30,000 9,200 39,200 Santa Clara River Eastern 100 300 Uoo 100 300 Uoo Piru 2,200 9,100 11,300 2,200 9,200 11, Uoo Fillmore U,600 16,100 20,700 U,600 17, Uoo 22,000 Santa Paula U,700 16,500 21,200 U,700 18,100 22,800 Mound 22,500 k,\m 26,900 22,500 5,200 27,700 Oxnard Forebay 1,200 Woo 5,700 1,200 5,200 6, UOO Oxnard Plain 59,800 31,200 91,000 59,800 37,100 96,900 Pleasant Valley i8,Uoo 31,800 50,200 18, UOO 39,200 57,600 Subtotals 113,500 113,900 227, UOO 113,500 131,700 2U5,200 Calle guas -Cone j o Simi 12,900 7,200 20,100 12,900 7,900 20,800 Last Las Posas 7,500 26,300 33,800 7,500 31,200 38,700 Vfest Las Posas 3,700 12,000 15,700 3,700 1U,U00 18,100 Conejo 20,500 6,100 26,600 20,500 7,800 28,300 Tierra Rejada 600 2,000 2,600 600 2,700 3,300 Santa Rosa 1,200 U,300 5,5oo 1,200 5,700 6,900 Subtotals Ii6,!i00 57,900 10ii,300 Ii6,li00 69,700 116,100 ialibu 12,300 1,U00 13,700 12,300 1,800 1U,100 Remainder of County* 1,800 3,000 U,800 1,800 3,500 5,300 TOTALS 20U,000 I8!i,700 388,700 20U,000 215,900 Ul9,900 Includes scattered residences throughout County, together with about 2,000 acres of land requiring water service in Cuyama River drainage area and in upper reaches of Piru Creek drainage area. 3-53 Demands for Water The term "demands for water", as used in this bulletin, refers to those factors pertaining to rates, times, and places of delivery of -water, losses of water, quality of water, etc., imposed by the control, development, and use of water for beneficial purposes. Those demands relating to times, rates, and delivery of water, and permissible deficiencies in application of water must be given consideration in preliminary design of works to meet supple- mental water requirements and are, therefore, discussed in the following sec- tions. Demands relating to application of water to satisfy beneficial use have been discussed previously. Monthly Demands for Uater Because of the erratic occurrence of precipitation and stream flow in Ventura County, both seasonally and monthly, there is wide variation in the monthly percentage of seasonal irrigation demand. Hide variations also prevail both in the rate and period of demand for irrigation water for different crops. Generally, most irrigation water is applied during the months from April to November. However, the increasing double and triple cropping practices in the coastal plain of the Santa Clara River Valley impose demands on artificial water supplies throughout the year. Furthermore, with diminution of winter rainfall during protracted periods of drought, perennial crops such as citrus, deciduous orchard, and irrigated pasture require winter irrigation to supplement defi- ciencies in natural supplies. However, during a year of subnormal rainfall, with expedient distribution, winter irrigation may not be practiced. In the aforementioned coastal plain of the Santa Clara River Valley, if there has been insufficient precipitation in the spring to achieve proper soil moisture condi- tions, it is common practice to pre-irrigate bean land prior to planting. Vj'ith 3-ft leavy spring precipitation, beans are not usually pre-irrigated, and the require- ment for ground water supplies in such a season is substantially reduced. Studies of irrigation practice in Ventura County indicate that for certain crops the monthly percentages of seasonal demand for water have varied from zero in the minimum month to as high as 33 per cent in the maximum month. During drought periods, although monthly percentages of seasonal demand have been more uniform throughout the season, total amounts of applied water have been greater. Since use of water in urban areas is influenced only slightly by the magnitude and occurrence of precipitation, monthly percentages of seasonal demand for urban water remain rather constant seasonally, and also show a more uniform monthly distribution than do monthly irrigation demands. Presented in Table U6 are estimates of average monthly distribution of seasonal demands for irrigation water for mean and drought periods, together with those for average monthly distribution of seasonal demand for urban water. Estimates of monthly urban demands were based on analysis of water deliveries and water production by the Cities of Ventura, Port Hueneme, and Oxnard. Irri- gation demands were estimated from data obtained from representative water service agencies, mutual water companies, and individual consumers, and from analysis of records of agricultural power consumption obtained from the Southern California Edison Company. 3-55 bi o E^ ««■ S u s ■d ra m -p E-i S o -p CO E-t rH M ~-h cO Q r-^ § ** S CO S 3 o co CI) H Eh to a 3 cj P a M p O !=> XI o COD 1 o P CO -ft o rt -jO £ co p M d 5 31 o 33 CO 3 Xi •£ +j cd 3 o •\ to a) ed •H >? «J -P H (0 (fl o c o CO TJ a a 0) On CO t»c 03 h o -p O Tl nH A Cjh £ CO O u TJ TJ -H T3 p o o § q s £ a •H P g-sl-S^, 03 O H CO CO • • bC Oh > •H *__ S-H u TJ TJ CO 0^ u C fnH G H 3 oj H cd 3 IX p» 03 03 CO ££ O H O •N »\ Tl co co O *H P •H O -H (h S d fn 03 CO H P CO P p. '-• 9 > -d •H P .H B p fn CO Ch P 43 tx p •» oJ aj O H p ro 'to •H 03 H O o *H Q ^liOH O • • *> 03 oJ f-\ C P P p CO 05 Oj >— . q P CO CO 03 CO .CO 03 TJ s w g CO si ,o g h 1 J3 CD ■3 x p d o a 1 co^OO wnvo rococo JHH • ••••••••••• CO ^O f»^OJCM_^-t^-C\JC\J^J-0-\'M H r4 r-\ r-ir-i OvO CM C^-^0\ArlXAO WO\r- H rH H H H -d-j-^tA-^m cm o *0 p«- o\c\j o co ^ J n-4 c^- o o o hcnj rH r4 r-l r-1 r-i r-i co mHcocNN HCNiCJ-d-r-co H H H H H l^-CM (H mr>-_3CO m CmH XAvO • ••••••••••• Oco v O-d-H_J-d' o"\ O H H H H H H fncvivOOOmHOVA^OJO • •••••••«••• O OsvO r^HCM m C\J oj .J- en c\J o o O H O o o o H o o H o o S Q CO 4 h& ^3 EH o U 03 p a Z-* oJ p 43 H 10 CO 2 ^ O 'H rt ? ? 3d) co co oj a< *-a fc 3 < a ^ t-3 < CO o - •H M O H 2p II ol o P 'to P o d h CO o > ti p s O K CO 0} s* §^ £> CO P> CO ch h o CO J> CO •H +5 'd 03 3 el P CO G co C > o o Jh fl © -H cu ?=> ^ • c P TJ 03 •H 2 C 0} Jh & •» > O •^ •H bO *rj O O CO H "I 'oj g O ! •r-5 © K O > P J3 Jh ^ © CO •H a =s H Ph o CO •^ t-5 ^ •S.S a © CO CO H H H -9 -9 rQ 03 0} cO o o o •H -H •H H rH rH & oj cO cO © CO 0) X rO ,o o o o p p p TJ t) T) CO CO CO p p P 03 CO gj 6 E g •H -H •H P P P CO CO CO wan OJ X! CJ 3-56 Irrigation Efficiency Satisfaction of the consumptive requirements of irrigated crops requires the application of water in excess of consumptive use. The ratio of consumptive use of applied water to the total amount of applied water 3 expressed as a percentage, is termed "irrigation efficiency", and is useful as an indi- cator of prevailing irrigation practice. Irrigation efficiency varies widely between crops and among plots devoted to the same crop. These variations are accounted for in differences of root depth, soil type, topography, method of irrigation, drainage characteristics, and in the practices of the individual irrigators. During the course of this investigation, studies were made in selected areas by both the Division of T iater Resources and by the United States Soil Conservation Service to ascertain approximate irrigation efficiencies. The Soil Conservation Service in their report, "Ground Water Replenishment by Pene- tration of Rainfall, Irrigation and Viater Spreading in Zone 3, Ventura County Flood Control District, California", dated April, 1953* estimated the average irrigation efficiency during the base period for predominant crops in the Pleasant Valley Subunit of the Santa Clara River Hydrologic Unit, and for the several subunit s of the Calleguas-Conejo Hydrologic Unit. The estimates of the Soil Conservation Service were made by comparison of records of actual application of water to crops and estimated optimum values of consumptive use of applied water. These studies indicated that irrigation efficiencies of 85 tc 90 per cent prevailed for citrus, 95 to 100 per cent for walnuts, Ik to 77 per cent for alfalfa and irrigated pasture, 58 to 6k per cent for beans, and 70 to 75 per cent for summer truck crops. In the case of walnuts, it appears probable that actual consumptive use of applied water was less than the computed values used in the studies, and that actual irrigation efficiency was less than the foregoing figures indicate. 3-57 It is known that even under the most favorable conditions a 100 per cent irrigation efficiency can rarely or never be achieved. Application of water sufficient to meet consumptive requirements v/ill result in either deep penetration beyond the root zone of the crop under irrigation, or waste from the lower end of the field. Comparison of records of application of water with estimates of consumptive use of applied water in the Piru, Fillmore, and Santa Paula Subunits of the Santa Clara River Hydrologic Unit indicates that irriga- tion efficiencies on citrus approximate 60 per cent. Irrigation efficiencies on citrus and walnuts in excess of this value were noted in the Oxnard Plain Subunit. However, in this area, it is possible that these crops draw upon rain- fall percolation and return irrigation water stored in the semi-perched ground water body, thereby reducing applied water requirements and increasing the apparent irrigation efficiencies. In general, it is believed that, with the cited exceptions, an over- all irrigation efficiency of about 70 per cent is being achieved in Ventura County at the present time. Irrecoverable Losses Attendant with the beneficial use of water, including the irrigation of crop land and the delivery of urban and suburban supplies, there may occur certain losses of water which cannot be recovered for further beneficial use. As used in this bulletin, the term "irrecoverable losses of ?jater" refers to the water applied to irrigated crops in excess of beneficial consumptive use in confined ground water areas, wherein re-use cannot be effected, and to the sexvage effluent from urbanized areas which is discharged to the ocean or otherwise lost for re-use, together with any transmission or delivery losses incurred, which are not susceptible to re-use. These losses comprise an additional demand on the supplies of Ventura County over and above consumptive uses. Comparison of 3-58 present consumptive use of applied water with estimated present water require- ments in Ventura County indicates that present mean seasonal irrecoverable losses amount to about 22,000 acre-feet. Permissible Deficiencies in Application of Water Studies to determine deficiencies in the supply of irrigation water that might be endured without permanent injury to perennial crops v/ere not maie in connection with the Ventura County Investigation. However, such studies have been made for other areas in California, and indicate that a maximum deficiency of 35 per cent of the full seasonal requirement can be endured if the deficiency occurs only at relatively long intervals. It has also been determined that small deficiencies occurring at relatively frequent intervals can be endured. In connection with the studies for this bulletin, no allowances were made for deficiencies in water supply. Even though it is known that portions of Ventura County subsisted on deficient water supplies during the latter years of the recent drought period, all estimates pertaining to water requirements were based upon the assumption that adequate water supplies would be provided to produce optimum crop yields each and every year. Similarly, estimates of requirements for urban and suburban entities did not allow for deficiencies in supply. Supplemental Water Requirements As has been stated, the security of existing developments and econo- mies in Ventura County is threatened by water supply shortages which develop 3-59 during periods of drought, by perennial lowering of ground water levels, and by the intrusion of sea water into pumped aquifers. Furthermore, the growth and en- hancement of the economy of portions of the County have been impeded by the lack of firm water supplies. Elimination of present water resources problems and pro- vision for indicated increased future water requirements of the County will re- quire the development of additional water supplies. The amounts of water so re- quired have been designated "the present and probable ultimate supplemental water requirements". As previously defined, the term "supplemental water requirement" refers to water requirement over and above the sum of safe ground water yield and safe surface water yield. Present and probable ultimate supplemental water re- quirements were determined both for the mean period of water supply and climate, which conditions were taken as equivalent to those occurring during the base period, and for the drought period. Differences in mean and drought period supplemental water requirements, presented in this section, result from the effect of seasonal and cyclic climatic variations on water requirements and water supply utilization. Consideration was not given to possible utilization of developed water supplies during wet periods in excess of established safe yields. Present Supplemental Water Requirements Present supplemental water requirements were estimated for each of the hydrologic units and subunits of Ventura County by deducting the estimated safe yields of presently developed water supplies, corrected for importation and ex- portation, from estimated present water requirements. The present mean seasonal supplemental water requirement for the County was so determined to be about 73>000 acre-feet. It was further estimated that the present requirement for supplemental water increases during drought periods to about 89,000 acre-feet per season. Requirements for supplemental water during periods of drought are of 3-60 articular significance in the Ventura and Santa Clara River Hydrologic Units be- ause of the limited natural and artificial water supply regulation in portions >f these units, and because of the substantial increase in water requirements therein during drought periods, particularly in the latter unit. Comparison of ;afe yields of developed water supplies with drought period water requirements erves to establish the magnitude of the water resources problems in these hydro- Logic units. In the Calleguas-Conejo Hydrologic Unit the drought period require- nent for supplemental water is of lesser significance, since water resources problems therein are largely manifest in perennial lowering of ground water levels, resulting from ground water utilization in excess of mean recharge, rather than in the lack of adequate natural or artificial regulatory storage capacity. Table hi presents the estimated present mean and drought period seasonal supplemental water requirements in Ventura County by hydrologic units and subunits. It may be noted that in some cases values for available safe water supplies in Table hi for the drought period exceed those presented for the mean period. This results from differences between wet and drought periods in seasonal imports of water to and exports from the several hydrologic subunits, and from the variance between wet and drought periods in water supply and disposal in ground water ba- sins. Under "safe yield operation" of those ground water basins wherein safe yield is governed by the amount of mean seasonal replenishment, rather than by basin storage capacity or configuration or by aquifer transmissibility, increased water utilization during a drought period, with attendant reduction in replenish- ment, would effect a depletion of ground water storage. During ensuing wet sea- sons, with lesser utilization and increased replenishment, ground water levels would recover to positions prevailing at the beginning of the former drought period. Thus, over a mean period of water supply and climate there would be no net change in ground water storage, and the criterion governing safe yield in such basins would not be violated. Values presented in Table hi under columns 3-61 headed "Net effect of modified imports and exports on safe water supply" and "Net effect of changes in remaining items of water supply and disposal on safe water supply" were derived from data and by methods and procedures presented and dis- cussed in Chapter II. For reasons discussed hereinafter in Chapter IV, it was assumed that the net safe yield of water developed by Llatilija Reservoir, in the estimated amount of about 1,1;00 acre-feet per season, would be entirely utilized in the Ojai Subunit, 3-62 lO *— oi s: UJ c£ LU UJ -J 2: 1 lu : _l o_ 1 0_ 1 LO _l ' < I 2L O I CO <. LU I LO 1 Q O 1 s Q CC 5 < CO UJ CC a. Q LU I— -•£ 5- LO LU ro ■♦- -♦— c c 3^ QJ k. 6 e (LI 0) 3 M =c c +- ■/I 1 01 ■0 k. V c e co ro —• CD •a co Oil 0) +- >■ l_ ro ra -»— +- ro CO — « E ■ — g >. c/i 3 Q Z — CO +- z 01 "O 1 k. k. a k. CD .— O O (L> Q. Q ti_ a a a.-- D u_ e x co CO a> e •— c 2 - CO 3 3 ■0 CO •- LO >- ■*- c CD -. e qj — < XI >> IS co i 1 — « u_ 3 0) < ** -(- -(- > «_ O (/> ro S i^- Q.X) +- 3 a CU E C k. a u IB O 1) p 2: •+— O.u- CO a, u— X CO z O CD 60 ■a co — ■ u_ CD CO ■- CO >» •♦- c k. e CO CO -t- k. 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OOOOO OOOO O O O O O O O O — • O *-0 CO i 5 ^ CM •— 1 CO •JJ •—« vO ~T OLfNOO ft CM ft CM |N- vO CM NN. CM CM UN O 00000 O O O O O O O OOOOO O O O O O O 1^ NN.CM K\l — UN CO co Ft ON n0 vO CO 00 ft ^ r- _*un — NN. CO — d a to -)- o. — ■ C -3 O CD D 3 -t- +- C C k. k, CO 0) a 3 a o -3 _J O D O LO c cc 5n *-»».--*. ?> -J O 1/) CI ^-■fl.>-"* ra — . — . .13 CO ro S3 c — • to CO CO CO T3 (0 a; co co ■- co k. CO > 13 C OO a. a. ro — . ro ro D — « +- u (U CO -t- l0 OJ CO l_Q.-t- 1 C/l CO 0. _l OJ c c +- CO vvj CO CC +• ■O O (3 X) co _i _j CO X) t— a> S CO "O i- 1- (0 D k. ro D O -) — 1 -t- r to ro co 1/1 OJI— +■ -t- OJ k. -»- LO D t— (0 c/) k. — * c 3 C c OJ co e (/) co c_ CO c x> -t- CD ■— CO n X X —1 — < •— CO CO •— CO ^ Uia - ll. lo s: a. -HOUJ3 CO CJ t— LO ro CO 2: 3-63 Probable Ultimate Supplemental Water Requirements The probable ultimate mean and drought period seasonal supplemental wa- ter requirements in Ventura County were derived by comparison of probable ultimate water requirements and safe yields, and were estimated to be about 266,000 and 287,000 acre-feet, respectively. In the derivation, consideration was given to the effects of probable future increased use of the major ground water basins on previously estimated values for presently developed safe yield. Table ii8 summarizes, by hydrologic units and subunits, the estimated ultimate supplemental water requirements for mean and drought periods. The sup- plemental requirements presented in Table h& are for probable ultimate areas re- quiring intensive water service. It was assumed that supplemental water would not be required to meet requirements of previously discussed minor water service areas throughout the County. A brief discussion of methods and assumptions employed in deriving the ultimate supplemental requirements follows: Ventura Hydrologic Unit . It was concluded that in the Ventura Hydro- logic Unit, without construction of additional regulatory works, the yield of present sources of water supply would be no greater with the probable ultimate pattern of land use and attendant water requirements than under present conditions. It was assumed, however, that ultimately the effective storage capacity of ilatil- ija Reservoir would be entirely lost through siltation, thereby reducing the safe yield of the presently developed water supply in the Ventura Hydrologic Unit, estimated to be 9*^00 acre-feet per season, to about 8,000 acre-feet per season. Probable ultimate supplemental water requirements were derived using this latter value . • Santa Clara River Hydrologic Unit . In the Santa Clara River Hydrologic Unit, consideration was given to the effect of increased development in that por- tion of the Santa Clara River watershed designated Eastern Basin, and included within Los Angeles County, on flow in Santa Clara River at the county line. Land 3-6U classification surveys, conducted in connection with the preparation of State Wa- ter Resources Eoard Bulletin No, 2, indicated that there are about 38*000 acres of land susceptible to water-using developments in this area, as compared to pres- ent water service area of about 10,000 acres. The ultimate mean seasonal water requirement was estimated to be in excess of 60,000 acre-feet, as compared to a present water requirement of about 18,000 acre-feet. Although with data at hand it was not possible to evaluate with any degree of accuracy the effect of this probable increase in development on inflow to Ventura County, for purpose of anal- ysis it was assumed that ultimately effluent discharge at the lower limit of Eastern Basin would be entirely eliminated. The amount of this discharge was estimated to average about 15>,000 acre-feet per season over the base period, with the present pattern of land use and water supply development in Eastern Basin. This assumption may be somewhat severe with respect to the reduction in the ulti- mate water supply of Ventura County, since it is probable that with increased use of ground water storage in Eastern Basin effluent discharge would not be entirely eliminated. Furthermore, such increased use also would effect a reduction in flood flow in Santa Clara River at the county line, a large portion of which presently wastes to the ocean. In this regard, it was assumed that a forecast increased water requirement of 100 acre-feet per season in the portion of Eastern Basin with- in Ventura County would be satisfied from surface or ground water supplies in Los Angeles County, tending to increase the safe water supply available to Ventura County by that amount. In addition, it was assumed that lands in the Piru Subunit nor being supplied both by effluent discharge from Eastern Basin and by import from Los Angeles County would ultimately be entirely supplied by import from Los Angeles County. Under this assumption, the ultimate mean seasonal import to the Piru Subunit would be increased by about £00 acre-feet over that estimated for the present, and would average about 2,300 acre-feet. Monthly studies of water supply and disposal were made for Piru, Fillmore, 3-6S and Santa Paula Basins over the base period, with the probable ultimate pattern of land use prevailing therein and with the foregoing assumed changes in water supply. With exception of forecast changes in land use, water requirements, and water supply, methods and assumptions employed in the studies were identical with those used in the analysis for present conditions of development, as described in Chapter II. In commencing the studies, Piru, Fillmore, and Santa Paula Basins were assumed to be full in the spring of 19Uu By the fall of 195l> it was esti- mated that ground water storage depletion in Piru Basin would be about UjO,000 acre-feet, as compared to an actual depletion in the fall of 1951 of about 9ii, 000 acre-feet; that ground water storage in Fillmore Basin would be depleted by about 88,000 acre-feet, as compared to an actual depletion of about 61,000 acre-feet ; and that ground water storage depletion in Santa Paula Basin would be about 70,000 acre-feet, as compared to an actual depletion of about 22,500 acre-feet. Assum- ing a ground water storage depletion in each of these three basins in the fall of 1936 equal to that which was estimated would occur in the fall of 1951 under ulti- mate conditions, it was found that Piru Basin would be first filled in the spring of 19 III, and that Fillmore and Santa Paula Basins would be filled by the spring of 1937* It was therefore concluded that, under the assumptions of the study, there would be no ultimate requirement for supplemental water in either the Piru, Fillmore, or Santa Paula Subunits. It was estimated that greater use of Piru, Fillmore, and Santa Paula Basins under ultimate conditions would effect an increase in mean seasonal safe yield of these subunits by about 15, 500 acre-feet over the present safe yield. Conversely it was estimated that with a further lowering of ground water levels in Santa Paula Basin there would be reduction in both effluent discharge and sub- surface outflow therefrom to Oxnard Forebay Basin 3 thereby reducing the estimated present mean seasonal safe yield of the latter basin by about ii,300 acre-feet. Thus, the ultimate net increase in safe water supply of the Santa Clara River 3-66 tfydrologic Unit was estimated to be about 11,800 acre-feet per season, including the assumed increased import to the Eastern and Piru Subunits in the amount of 600 acre-feet per season. The safe yield of water supplies available to meet requirements under ultimate conditions of development in the Oxnard Forebay, Oxnard Plain, and Pleas- ant Valley Subunits would reflect the estimated h*300 acre-foot per season reduc- tion in safe yield of Oxnard Forebay Basin. Accordingly, it was estimated that this ultimate safe supply would be about 18,800 acre-feet per season during drought periods and about 19,900 acre-feet per season during mean periods. Although it appears that underflow from Santa Paula Basin to Mound Basin would be reduced under estimated ultimate conditions, the magnitude of the prob- able reduction could not be evaluated with information at hand, and the safe yield of presently developed water supplies of the round Subunit was assumed to remain constant ultimately. Calleguas-Conejo and Malibu I-Iydrologic Units . It was concluded that the ground water basins in the Calleguas-Conejo and Malibu Hydrologic Units are pres- ently being utilized to the maximum practicable extent, and that any increased utilization thereof would either result in the establishment of overdraft or would increase existing overdrafts. Ultimate supplemental water requirements, therefore, were estimated by comparison of probable ultimate water requirements with safe yields of presently developed water supplies. 3-67 LU z: 3 or < z LU UJ -J o. §*: 1/1 ? _J o z —» — < (0 a * a a ao —•a. J- ce o LU Q_ c/1 d I 2 8 D O '_) oe —• o3 z o si LU S 2 _l LU d Q. § 0) 2 >. io a) w. — • ->u. 4) o. •- .0 •+- a. co en co d > * ..: < ♦- c e »- c a> cut-— io — • c 4) -C O 0 — (0 >> 1/1 3 — o Qfl a a to -o 0) +- >■ Q — 3 Q *9 o o o o St UA (/) 10 ■«- -»- -4- U I k L +- u_ "O T3 C a> k- e e 3 io ■*- in c »- u ■♦- 04; 4> v. ■+- >. u_ O 10 (0 — • (4- a"D +- 3 Q. U B C W O. — (0 O 4) O •*- Q.O- <0 4> ii_ X <0 2 O 4> OT •o 0) — . u- 4) CO •- in >• l. e 4J 4> -t- k- CO — 3; D vT U C -f- ~> (J 5 Q 1111 .) 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PLANS FOR Y/ATER SUPPLY DEVELOFi»iENT It has been shown that current water resources problems in Ventura County include perennial and progressive lowering of water levels in certain ground water basins of the Calleguas-Conejo Hydrologic Unit, overdraft on ground water supplies in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins of the Santa Clara River Hydrologic Unit, resulting in the intrusion of sea water to pumped aquifers during periods of drought, and the utilization of both surface and ground water supplies in the Ventura Hydrologic Unit in excess of estimated safe yields. It has also been shown that there is an estimated mean seasonal requirement for supplemental water in the County of about 73*000 acre- feet at the present time. It has been further shown that elimination of present water resources problems, together with provision for anticipated future growth of the County, will ultimately require the development of supplemental water in the estimated mean seasonal amount of about 266,000 acre-feet. Sources of supplemental water are available locally in the portion of runoff from watersheds of the Ventura and Santa Clara Rivers that presently wastes to the ocean, which portion would have averaged an estimated 230,000 acre-feet per season over the base period with the present pattern of land use and water supply development. Utilization of this presently wasted water will require the development of equalizing storage capacity either in ground water basins or in surface reservoirs, and construction of facilities to equitably distribute the water so conserved to areas of need. Studies described in this chapter indicate that, because of the erratic nature of the occurrence of runoff in Ventura and Santa Clara Rivers, in excess of 1,500,000 acre-feet of storage capacity would be required to effect complete salvage of this surface waste. Furthermore, because of the relatively high cost of developing surface storage capacity, together with a general paucity of feasible dam and reservoir sites, it is indicated that presently undeveloped ground water storage capacity should be exploited to the maximum practicable extent. It is concluded that under the limitations imposed by economic feasibility, insufficient local water could be conserved and equitably distributed to satisfy present supplemental requirements, and that final solution of the water resources problems of Ventura County must lie in importation of Tvater from outside sources. As was stated in Chapter I, the Division of Y/ater Resources is presently conducting surveys and studies for the State-V/ide Water Resources Investigation, under direction of the State V/ater Resources Board. This investigation has as its objective the formulation of The California V/ater Plan for full conservation, control, and utilization of the State's water resources, to meet present and future water needs for all beneficial purposes and uses in all parts of the State, insofar as practicable. Although the investigation is still in progress, it is sufficiently advanced to permit tentative description of certain major features of The California V/ater Plan which would provide supplemental water to meet the probable ultimate requirements of Ventura County. These projects, which are described in general terms in this chapter under the section entitled "Plans for Importation by Lleans of Feather River Project", would also provide supple- mental water supplies for other water deficient areas of California. In addition, benefits from the projects would include hydroelectric power, flood and salinity control, mining debris storage, and incidental benefits in the^ interest of recreation and preservation of fish and wildlif e. In general, the major features of The California V/ater Plan which were mentioned in the preceding paragraph would be large multipurpose projects requiring relatively large capital expenditures. Additional study will be required to estimate final costs and to determine possible means of financing these major projects. Plans presented in this bulletin for the further develop- ment of local supplies are those under consideration for current financing, U-2 construction, and operation by appropriate local public agencies. The proposed local developments would be such that the works could be integrated into the foregoing major features of The California Water Plan* Descriptions of various plans considered for the conservation and utilization of local water supplies in Ventura County, and of plans for importing water from available sources outside the County, are presented in this chapter, under section headings designated "Plans for Local Conservation Development", "Plans for Importation by Means of Feather River Project", "Plans for Importation by Means of Metropolitan Water District of Southern California", and "Discussion of Alternative Initial Plans for Water Supply Development". Included therein are estimates of costs of the various plans, estimates of the amounts of supplemental water that would be made available by their adoption and construction, and an evaluation of the plans from the standpoint of economic and financial feasibility. Design of features of plans presented herein was necessarily of a preliminary nature and primarily for cost estimating purposes. More detailed investigation, which would be required in order to prepare construction plans and specifications, might result in designs differing in detail from those presented in this bulletin. However, it is believed that such changes would not result in significant modifications in estimated costs. The capital costs of dams, reservoirs, diversion works, conduits, pumping plants, and appurtenances included in the considered conservation, conveyance, and distribution systems were estimated from preliminary designs based largely on data from surveys made during the current investigation, both by the Division of Water Resources and other cooperating agencies. Approximate construction quantities were estimated 4-3 from these preliminary designs. Unit prices of construction items were deter- mined from recent bid data on projects similar to those in consideration, or from manufacturers' cost lists, and are considered representative of prices prevailing in the spring of 1953. Estimates of capital costs included costs of rights of way and construction, plus 10 per cent for engineering and l£ per cent of the construction costs for contingencies, and interest during one-half of the estimated construction period at k per cent per annum. Estimates of annual costs included interest on the capital investment at 1* per cent, amortization over a l-tO-year period on a h per cent sinking fund basis, replacement, operation and maintenance costs, and costs of electrical energy required for pumping. Plans for Local Conservation Development Consideration was given to enhancement of the presently developed yields of local water supplies, both through construction of equalizing storage capacity in surface reservoirs and in ground water storage. From the results of reconnaissance examination of many possible dam and reservoir sites through- out the County, it was concluded that detailed consideration should be given to ten of the more favorable sites, located in the Ventura and Santa Clara River watersheds. In connection with the studies of further conservation of local water supplies, consideration was given to transfer of surplus water between hydrologic units. Planned operation of certain ground water basins of the County, either by their greater utilization or by changes in present pumping patterns, or both, would increase their utility by providing additional usable storage capacity for water supply regulation. The Ojai, Piru, Fillmore, Santa Paula, and Oxnard Forebay Basins were studied in this regard. In addition, the Simi and East and West Las Posas Basins were studied from the standpoint of providing regulation for potential imported supplies. Certain legal considerations regarding the it-l vested rights of overlying users must be recognized in such planned operation of ground water storage. As has been stated, water susceptible to capture by the construction of surface reservoirs in Ventura County, or by further development of ground water storage, is that which would waste to the ocean over a mean period of water supply and climate with the present pattern of land use and water supply development. Estimates were made, therefore, of the portion of this waste occurring during the base period which originated in the Ventura and Santa Clara Rivers and in each of the major tributaries of these rivers. The results of these estimates are pre- sented in Table U9 - It should be pointed out that values presented in Table k9 for the Santa Clara River were derived under the assumption that Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins would be operated in accordance with their safe yield. Since records of surface outflow in the Santa Clara River during the base period are not available prior to the season of 19U7-U8^ the values presented in Table k9 are based entirely on estimates, evaluated by methods and procedures described in Chapter II, and because of the nature of the studies are only indicative of magnitude. Seasonal amounts of waste to the ocean from the Santa Clara River system originating in each of the indicated major tributaries were determined from analysis of the monthly hydrologic studies presented in Chapter II. Values presented for waste to the ocean from the Ventura River were determined by correcting measured amounts of runoff at the gaging station near Ventura for impairment by Matilija Reservoir prior to 19^8, and for differences in actual historical diversion by the City of Ventura from the estimated present sea- sonal diversion and pumping requirement of that City. It was assumed that any other differences in the land use pattern and attendant use of water in the remainder of the Ventura River drainage area during the base period from that estimated for U-5 the present were negligible and would not affect measured runoff at the foregoing station. It was assumed that the measured runoff of Coyote Creek near Ventura represented the waste to the ocean from that stream during the base period. Estimates were made of the present impairment to the full natural runoff of both l.iatilija and North Fork of katilija Creeks, to determine the portion of the previously estimated waste from the entire Ventura River system originating therein. '.Taste from the remainder of the Ventura River system, shown in Table U9, was then determined as a differential. fc-6 ■O CO o +-n c c ac (U io ON -3- a uj o J" s: S a o uj ac a. >- u. _J ID Q. zwa UJ 10 ■-• <^> JKZ «* <* < id- 1 1-0 U. <: < o ui t— *Si z z Ql/lUJ UJ t— J— o t— < z < s: 0_ as v. — . ca ro -. k. CJ ro - -Q -t- 0C c/> c3 to ~Z 6 u_ C0 O c c co 3 CO .* — 4) CO k. Q. U I" 0) a) CO to u 3 - > c .2.8 O CO >Jj ■+- co ~ ~ > _ - o c/i oc o o o — . CO ca k. 4- D CO o +■ > tc- XJ to - V) \~* 3 CO o U O) o CO C C - co 5 C —i k. — J^ —■ CO .- OJ -t- k. co u s: O — i J. — _* _ -■ flj x — co ♦- •♦- k. k. CO u o 2: 0§L o°oo — • rr >J3-C3N « •> •. •. 00 H(C\CA LO UN 00 KN CM NO © 0000 O J>nO o CM *— O ^^O CM OOOOO OOOOO r-. uni — on 00 UNnO -3-l/MJ"\ lAOvfiCVIO o — 1 un-s- — 1 00000 c d p o q .3--=»-r- -3n0 -V * * * * cm I s - o MN.r- O CB NN if\! — 00 -=J-r * * CM IO OJ ONnO OOOOO o o nO UN o no F> LTV CO +- .* O 4) >. CO O i- CO CO CO 27,000 84,700 6,600 2,700 OOOOO OOOOO r— 00 onunnn •. »s *> •« » -. UN ON CM f~- P- -3 O Q O O O CO KN 00 r— 0000 0000 O O CM OO •v •* * * ONCO -3-— 1 — NN 55,200 56,100 18,800 7,000 OOOOO ON ON L/NfCN OOOO OOOO 00 ir\-« •» « * •» — r>- oo _3 0"» CM — CM 570,600 28,700 163,800 125,100 56,200 OOOOO r*- to NACM Q O O O OOOO oo 00 vo tr> _ 00 — OOOOO OOOOO uNtr>tr>SN j?0 00 CTsnO O CM CO ON •— CM OOOOO CM ON OOOO OOOO — 00 00 00 ^sOO C\J OOOO 0000 ON>J3 kSON * ^ ^ •» t~-NO i*~ 00 ON 00 — O q O O 0000 o if\ -a-fr\ fc » * » |n- UNf*- -=»■ CMO OOOO OOOO J- O -=tun OOOOO OOOOO OOOOO 00 ONifX J-IACO ^3-UN ONCMNO NO OOOOO OOOOO 00000 00 q KNOn^-CMOO —On CM £-£' 00000 oqooq OOOOO 00 o lAOfvlCM J OnO On -, A fc «S «v •« *S v£> I — ONONO j-cm tti OOOOO OOOOO on on—" u^^f^ •* •* ^ fc •» UN UN—" ON' — -. UNCM OOOOO O O NN.O O f•> a k « n k CMN0^f^CM OKNCOUNfN- CM CM U\ CM — < r— co ono KNKNNN. jt I I I I J) l*-CO ON NNKNKNKN ON ON ON ON — CM KN .=»■ UN j- ^r -a- -a- J- I I I I I o — < CM KA ^r ^T -3- -3" J" ^t ON ON ON ON On OOOOO 00 o nO 00 UN vO f*- 00 On o — < 3--* J- -3-UN UN I I I t I I UNsO IN-COON o JJtJJ^ UN ONONONONON On o o J>. ON CM 0* o o ON CM J>N o o ON •*< CM o o o 8 o o nO o o UN o o 00 vO UN o o KN o o CM CM o p o o CM o o o NO •t 8 n ON ON CM o o 00 en o o K\ N CM CM o o o o o UN |N^ NO o o UN CN o R co ON o o CM CO CM o o ON o o UN o o o o KN o o -3- o o o o UN o o UN o o CO o o UN o o ON o o CM o o CM I"- -3- +- KN J* 3 nO KS k. ON ON o — ■ — 1 "- ^x co "D tin O/l o o CO — o k. k. k. k. k. k. £ 0)-O 0/1 Sf 8 k. k. k. a-*- <: «x •a on o z> — o kj CO X a-t- -t- UN — ajx J" UN 0J1 CV 1 1 CO ki s ^UN CO k. c^cr* > -0 — < —-> «c U-7 Examination of Table U° will show that the estimated mean seasonal waste to the ocean from the Ventura and Santa Clara Rivers under the present pattern of land use and water supply development is about 230,000 acre-feet. It is also indicated that during a drought period the average waste would be about 38,000 acre-feet per season, or about 16-1/2 per cent of the mean. During the wet period, the waste would average about h00,000 acre-feet per season, which amount approaches twice the mean, and is over ten times greater than the average amount for the drought period. Thus, it is evident that the effective conserva- tion of local supplies requires development of carry-over storage capacity to reduce waste to the ocean during wet periods and make it available for bene- ficial use during periods of drought. P otential Surface Storage Developments Investigation of potential surface storage developments in Ventura County included hydrologic studies to ascertain the amounts of supplemental water that could be developed by construction of reservoirs, with various storage capacities at the several sites considered, geologic investigations to determine the suitability of dam sites as to type and height of dam, and esti- mates of capital and annual costs in order to establish economic relationships between various reservoir storage capacities at a given site and between the several sites. After preliminary reconnaissance, efforts were concentrated on more detailed investigation of the Casitas dam and reservoir site on Coyote Creek, a tributary of the Ventura River; the Ferndale site on Santa Paula Creek; the Cold Spring, Topatopa, Hammel, and Fillmore sites on Sespe Creekj and the Upper Blue Point, Blue Point, Devil Canyon, and Santa Felicia sites on Piru Creek. The locations of these dam and reservoir sites are shown on Plate 25, entitled "Potential Local '..ater Storage Developments and Conveyance Units for Importation of Y/ater to Ventura County". ii-8 Reconnaissance investigation of potential dam and reservoir sites in the Call eguas- Cone jo Hydrologic Unit, together with hydrologic studies, indi- cated that there are few feasible sites, and that present waste of water from Calleguas and Conejo Creeks is insignificant in comparison with present and probable future supplemental water requirements in the unit. Therefore, no further consideration was given to additional surface regulation and conservation of water supplies of these streams. Estimates were made of monthly runoff during the base period at each of the ten dam sites given detailed consideration. Estimates were also made of mean seasonal waste to the ocean of runoff originating above each of the sites under the present pattern of land use and water supply development. For various selected reservoir storage capacities at each site, monthly operation studies were made, utilizing the aforementioned monthly estimates of runoff for the base period, in order to determine relationships between storage capacity and yield. Monthly values for reservoir evaporation were estimated from available records of evaporation in Los Angeles and Santa Barbara Counties. Net safe seasonal yields that would be developed with construction of the considered reservoir storage capacities were determined by deducting, from yields derived from the operation studies, the amounts of water that would have been put to beneficial use by downstream surface and ground water users without construction of the reservoir. In operation studies for the proposed Casitas Reservoir, in the Ventura Hydrologic Unit, monthly percentages of seasonal reservoir draft were taken as equal to the estimated average monthly distribution of the seasonal demand for water of the City of Ventura, as shown in the following tabulation: h-9 Per cent of seasonal Per cent of seasonal Month reservoir draft Month reservoir draft October 9 April 8 November 7 May 9 December 7 June 10 January- 6 July 11 February 6 August 11 March 7 September 9 It was demonstrated in Chapters II and III that water problems in the Santa Clara River Hydrolo^ic Unit are manifest in overdraft on ground water supplies on the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, and that in the future ground water overdraft probably v/ill prevail in the Mound Subunit. It was also demonstrated that neither at the present time nor under assumed probable ultimate conditions of development would supplemental water be required in the Piru, Fillmore, or Santa Paula Subunit s. Thus, salvage of water presently wasting to the ocean in the Santa Clara River would be for the primary- purpose of alleviating ground water overdraft in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Sub units, and the measure of reservoir benefit would be the amount of new water that would be made available for beneficial use in these subunit s. The new water that would be developed by construction of reservoirs on tributaries of the Santa Clara River was determined from two operating criteria: (l) operation of the reservoirs on the basis of uniform seasonal releases to the Oxnard Plain, Oxnard Forebay, and Pleasant Valley Subunits, hereinafter termed the "uniform release" method, and (2) operation of the reser- voirs on the basis of rapid releases to ground water storage in the Oxnard Forebay Basin, hereinafter termed the "rapid release" method. Under uniform release operation, it was assumed that water stored in surface reservoirs would be released in equal seasonal amounts at monthly rates corresponding to the estimated average monthly percentages of seasonal demand h-10 for water in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits during a drought period. These monthly percentages are presented in the follow- ing tabulation: Month Per cent of seasonal reservoir draft Month Per cent of seasonal reservoir draft October 10 April 7 November 8 May 10 December 6 June 11 January 5 July 11 February h August 12 March h September 12 With such uniform release operation, lands on the coastal plain requiring supplemental water would be supplied directly from the reservoirs. Analysis indicated that, because there are from 12 to 27 miles of pervious stream channel between the proposed reservoirs and the Oxnard Forebay Basin, transmission losses would be prohibitive unless the stored water were conveyed to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits in a conduit. In the uniform release operation studies, releases were also made from reservoir storage to satisfy prior rights of downstream surface and ground water users. Sufficient water was so released to maintain ground water levels in Piru, Fillmore, and Santa Paula Basins in the fall of 1951 equal to those which would have prevailed without the reservoirs and with the present pattern of land use and water supply development. It was found that the maximum rate of extraction of water that could be maintained from each of the reservoirs was governed by the period of drought from 19liii-U5 through 1950-51. The net safe seasonal yield of a reservoir was taken as equal to this determined maximum seasonal extraction, less the average U-il seasonal reduction in water supplies otherwise available for beneficial use in Oxnard Forebay Basin resulting from operation of the reservoir. It was found that a substantial increase in new water would be realized in Oxnard Forebay Basin wore the aforementioned releases for prior rights in Piru, Fillmore, and Santa Paula Basins not made, thereby causing ground water levels in these three basins to experience greater lowering than would have occurred during the base period with the present pattern of land use and water supply development. Under the "rapid release" method of reservoir operation, it was assumed that demands for supplemental water on the coastal plain would be met from Oxnard Forebay Basin, and that the proposed surface storage developments would be largely utilized for temporary detention of flood waters for their sub- sequent rapid release to this basin. In the operation studies, releases were made from the reservoirs after cessation of heavy winter flow in the Santa Clara River, and when sufficient ground storage capacity was available for percolation of the released water in Oxnard Forebay Basin. It was assumed that the released *vater would be conveyed to Oxnard Forebay Basin in natural channels of the Santa Clara River and its tributaries. A conduit for this purpose was considered infeasible, because of the prohibitive cost of providing sufficient conduit capacity to accomplish the requii'ed rapid reservoir depletion. The rates of release were large enough to minimize percolation and other losses in ground water basins upstream from Oxnard Forebay Basin, but the maximum rates were limited by the amount of flow which could be percolated in Oxnard Forebay Basin, ".later was not released from the reservoirs when there was sufficient flow in the Santa Clara River to satisfy percolation demands in Oxnard Forebay Basin or when ground water storage in the basin was filled. It was attempted to deplete the surface reservoir storage each season, so that the maximum storage space would be available for capture of flood waters in the ensuing winter months. Under this rapid release method of operation, the net safe seasonal yield of the proposed reservoirs was taken as the average seasonal increase in L-12 water made available for beneficial use in the Santa Clara River system during the drought period. This new water would be comprised of the net salvage of surface waste during the period, plus water held over from the wet period in surface storage, less reservoir evaporation loss. However, since present and probable future water problems in the Santa Clara River Hydrologic Unit are considered to prevail in the coastal plain only, any of the salvaged water retained in ground water storage upstream from Qxnard Forebay Basin should not be considered as a manifestation of reservoir benefit. As has been stated, the measure of benefit from proposed surface reservoirs is the amount of new water made available for beneficial use during a period of drought in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits. The effect of replenishing the upper ground water basins with salvaged water would be to reduce their utility as natural regulators of Santa Clara River water. It was found that during the drought period reduction in waste to the ocean effected by the proposed surface reservoirs was about the same under either of the two methods of operation. However, the amount of new water made available at Qxnard Forebay Basin during the drought period was found to be substantially greater when a reservoir was operated by the uniform release method and the released water was conveyed to the coastal plan in a conduit. Selected combinations of surface reservoirs of varying capacities at certain of the more favorable sites were operated coordinately under each of the two foregoing operational methods. Because of the effects of reservoir opera- tion on downstream ground water supplies, the total yield developed by two reservoirs operated coordinately would be less, in some cases, than the summation of the yields of the two if operated alone. It should be pointed out that the net safe yield of a reservoir operated under either of the two foregoing criteria could exceed the estimated mean seasonal waste to the ocean of water originating above the reservoir site. 4-13 By withholding runoff in surface storage, greater amounts of other waters in the system would have an opportunity to percolate to ground water storage than is presently the case. The demand on stored water to maintain ground water levels that would have prevailed without the reservoir construction would be accordingly reduced. as has been stated, net safe yields of potential surface reservoirs in Ventura County were determined from water supply data for the base period from 1936-37 through 1950-51, and the magnitudes of yields so determined were governed by the critical drought period from 19kh-hS through 1950-51. It is known that the period governing safe draft that can be maintained indefinitely from a reservoir is dependent on relationships between its storage capacity and the magnitude and regimen of flow of the particular stream. For any given stream, the critical period of water supply may change for different considered reservoir storage capacities. In general, for reservoir storage capacities considered in this bulletin, the drought period from 19U2-1-U5 through 1950-51 did govern the magnitude of safe yield. However, exceptions occurred in several of the larger reservoir capacities studied, particularly as storage capacities approached magnitudes required to completely control a given stream over the base period. For such larger capacities, it was estimated that the critical water supply periods that occurred either from 1922-23 through 1935-36 or from 1917-18 through 1935-36 would usually govern safe yields. In such instances, appropriate qualification of the values of safe yield presented herein has been made. It should be emphasized again, however, that reliable records of surface runoff in Ventura County are not available for seasons prior to 1927-28, and that runoff estimates are necessarily based either on rainfall -runoff relation- ships or correlations with runoff of streams in Santa Barbara or Los Angeles Counties. Furthermore, at only a few of the dam sites under consideration are there stream gaging stations of such proximity thereto, that reliable estimates of runoff during the base period could be made. k-ik For each of the proposed surface reservoirs in Ventura County, consi- deration was given to future losses of effective storage capacity through sedimentation. The problem of reservoir sedimentation is of great significance Jin the County, and in comparable areas of southern California, because of the large bed loads carried by flood waters. Over a long period of years, the effective capacity of any reservoir will be destroyed through accumulation of sediment. The elapsed time prior to such complete loss of reservoir utility is dependent upon storage capacity of the development, and upon characteristics of the particular drainage area under consideration, such as soil type, vegetative cover, and nature and occurrence of runoff from the watershed. Brush and forest fires in a watershed reduce resistance to erosion and tend to increase sedi- mentation problems. Values for average seasonal rates of sedimentation utilized in this bulletin were obtained from reports by Harold Conkling, Consulting Engineer, entitled "Demand on Casitas Reservoir and Safe Yield", dated April, 19^0, and "Development of a Supplemental T iater Supply for Zone 2, Ventura County Flood Control District", dated September, 19h9» The estimates in kr. Conkling' s reports were obtained from "Flood Frequencies and Sedimentation from Forest Watersheds" 9 by Henry VJ, Anderson, California Forest and Range Experiment Station, United States Forest Service, Berkeley, California, dated February, I.9I49. For the proposed Casitas Reservoir on Coyote Creek, an average unit seasonal sediment production of 2.3 acre-feet per square mile of drainage area above the site was estimated. For watersheds of Sespe and Piru Creek, estimated seasonal values of 2 .U acre-feet per square mile and 1.6 acre-feet per square mile, respectively, were employed. The average unit seasonal sediment produc- tion of Santa Paula Creek was taken equal to that of Sespe Creek. Yields for all reservoirs considered in this bulletin were estimated on the basis of effective capacities that would remain after 20 years of operation. The con- structed capacity of proposed reservoirs is hereinafter referred to as the "gross reservoir storage capacity", and the effective capacity remaining after 20 years of operation is referred to as the "net reservoir storage capacity". Spillways for proposed dams and reservoirs in Ventura County were designed to pass the probable peak discharge from a flood having a frequency of once in one thousand years. Because of the preliminary nature of the designs, no consideration was given to the effect of surcharge storage in the reservoirs on reducing estimated peak flows over the spillways. Because of the erratic nature of occurrence of runoff in streams of Ventura County, there might be a considerable lapse of time subsequent to con- struction of reservoirs before they would be filled and in effective operation. A large reservoir constructed at the beginning of the critical water supply period from 1922-23 through 1935-36 might have required as long as 20 years to fill. On the other hand, a reservoir constructed immediately prior to the wet period from 1936-37 through 19h3-UU would have filled in a considerably shorter length of time. As has been stated, for over three years subsequent to its construction, in 19h8, Latilija Reservoir was virtually dry. Runoff occurring during the one month of January, 1952, filled this reservoir. As an aid in selection of desirable reservoir capacities to be constructed at certain sites appearing favorable in other respects, operation studies were made for the period from 189^-95 through 1950-51, for which period only rough estimates of seasonal runoff in Ventura County streams are available, to determine the probable average number of years that would elapse prior to filling the reser- voirs with various capacities. The following sections describe in some detail the results of investi- gation of each of the ten considered dam and reservoir sites in Ventura County. Certain of these results are depicted graphically on Plate 35, entitled "Relationship between Storage Capacity of Reservoirs and Capital Cost"; Plate 36, entitled "Relationship between Storage Capacity of Reservoirs and Net Safe U-16 Seasonal Yield "j Plate 37, entitled "Relationship between Net Safe Seasonal Yield of Reservoirs and Annual Unit Cost; and Plate 38, entitled "Probable Time Required to Fill Reservoirs after Construction." Yields for reservoirs on tributaries of the Santa Clara River utilized in preparing Plates 36 and 37 were those determined from the uniform release method of operation, with releases for maintenance of ground water levels in Piru, Fillmore and Santa Paula Basins. Costs employed in preparing Plate 37, however, do not include the cost of a conduit that would be necessary to realize the indicated yields, and are, therefore, indicative of the annual cost per acre-foot of new water at the reservoirs* ii-17 Casitas Dam and Reservoir . The Casitas dam site is located on Coyote Creek, about 2.5 miles above its confluence with the Ventura River and about 0.7 mile downstream from State Highway 150. A county road, the Casitas Pass Road, passes along the right abutment of the site, and joins State Highway 150 about one mile upstream. Both the dam site and reservoir area are within a former land grant, designated Rancho Santa Ana, The stream bed elevation at the dam site is about 325 feet, U.S.G.S. datum. Construction of a dam and reservoir at this site would permit conservation of flood waters of Coyote Creek, and of the Ventura River diverted to the reservoir, and would be for the primary purpose of providing supplemental water to the Ventura Hydrologic Unit. Consideration was also given to conveyance of water from the reservoir to the Santa Clara River Hydrologic Unit, The drainage area of Coyote Creek above the Casitas dam site comprises about 36 square miles, and produced an estimated average seasonal runoff of about 10,100 acre-feet during the base period. Under the plans considered, in- flow to a reservoir at the Casitas site would be augmented by diversion of sur- plus waters from the Ventura River. Seasonal runoff at the considered diversion site would have averaged an estimated 33>500 acre-feet during the base period had Matilija Reservoir been in operation, from a drainage area of about 75 square miles. Other Dam and Reservoir Sites Considered. Reconnaissance examinations were made of three other dam and reservoir sites in the Ventura River drainage area during the course of the investigation. The dam sites were located, re- spectively, on the Ventura River a short distance below the confluence of North Fork of Matilija Creek and Matilija Creek, designated the Nordhoff site; on the main thread of the Ventura River upstream from Foster Park and below the mouth of San Antonio Creek, designated the Arnaz site; and on San Antonio Creek immediately above its confluence with Ventura River, designated the San Antonio U-18 site. Although it was indicated that the two sites on the main thread of the river had certain advantages over the Casitas site, in that direct capture of the greatest portion of runoff of the Ventura River could be effected, probable costs of construction of dams at these sites were considered prohibitive* A dam at the Arnaz site would necessitate relocation of a branch of the Southern Pacific Railroad and a portion of U. S. Highway 399 f and in addition would re- quire the acquisition of several hundred acres of suburban residences in the reservoir area. Construction of a dam at the Nordhoff site would also necessi- tate relocation of U. S, Highway 399 > which in this vicinity would be an expen- sive undertaking, and would inundate the existing Matilija Dam. The San Antonio Creek site was given no further consideration because of the relatively minor runoff in San Antonio Creek, and because it did not compare favorably with the Casitas site for offstream storage of Ventura River water due to the limited storage capacity available. Areas and Capacities of Reservoir. The Casitas reservoir area was mapped up to an elevation of 5$0 feet in March, 195l> by the Ventura County Flood Control District, at a scale of 1 inch equals U00 feet, with a 25>-foot contour interval. The District also mapped the dam site in 19u9* at a scale of 1 inch equals 100 feet, with a 5-foot contour interval. Storage capacities of Casitas Reservoir at various stages of water surface elevation are given in Table !?0. U-19 TABLE 50 AREAS AND CAPACITIES OF CASITAS RESERVOIR Water surface Depth of water : elevation, : Water surface : Storage capacity, at dam, in feet : U.S.G.S. datum, in feet : area, in acres : in acre-feet 325 5 330 8 20 15 3k0 25 185 25 350 U8 55o 35 360 105 1,300 U5 370 170 2,700 55 380 235 U,700 65 390 290 7,300 75 Uoo 350 10,500 85 U10 loo lU,kOO 95 U20 u80 18,800 io5 U30 570 2i4,000 115 bho 670 30,200 125 U5o 730 37,200 135 U60 870 U5,300 1U5 U70 960 5U,hoo 155 U80 1,070 61i,600 165 U90 1,190 75,900 175 500 1,330 88,500 178 503 1,380 92,000 185 510 1,1*90 102,600 187 512 1,530 105,000 195 520 1,650 118,300 202 527 1,790 130,000 205 530 1,830 135,800 215 5U0 1,990 15U,900 215.5 5U0.5 2,000 156,000 225 550 2, mo 175,600 Geology of Dam Site. Geologic investigation indicated that the Casitas site is suitable for construction of an earthfill dam up to a maximum height of about 235 feet, which probably is about the upper limit from the topographic stand- point. The geology of the site was studied by George D. Louderback in 1948, by the D, R. Warren Company in 1946, and by J. B. Lippincott in 1934. During the course of the investigation, geologists from the Division of Water Resources examined the site and reviewed the prior geologic reports. Thirteen borings were made at the dam site in 194$, under the direction of Dr, Louderback, totaling about 4-20 1,310 feet of depth, of which about 924 feet comprised core borings. In addition, :hree tunnels totaling about 655 feet in length were driven into the right abut- nent. In 1946, the D. R. Warren Company drilled ten holes. During the Lippincott investigation, in 1934, six holes were drilled totaDing about 366 feet in depth. In addition, exploratory trenching was done on both abutments. The Casitas dam site is formed by a slight topographic constriction of the valley floor, where Coyote Creek has cut through resistant basal sand- stone layers of Vaqueros age. These hardei beds are inter-stratified with thicker, softer, shaly beds. The Vaqueros formation overlies a reddish, sandy, Sespe shale containing veinlets of gypsum, and in turn is overlain by grayish colored Rincon shale. All of these formations dip from 20 to 30 degrees upstream, which is a favorable attitude, and strike generally across the channel parallel to the proposed axis. The beds are slightly fractured, and although minor faults of slight displacement occur, they are generally sound and in reasonably good condition. The easterly extension of the more resistant Vaqueros beds, along the strike line, forms a relatively narrow ridge comprising the left abutment, with the downstream or southerly slope thereof being quite steep because of comparatively recent undercutting by Coyote Creek. Appreciably wide flat terraces are present on either side of the channel in the vicinity of the axis. The westerly or right abutment does not have so pronounced a ridge, although its upper portion shows the resistant Vaqueros beds, forming a small but sharply defined cliff above their contact in a ravine with the softer underlying Sespe formation. Both abutments are covered with a moderately heavy soil blanket estimated to be from 5 to 15 feet in thickness. A small slide or slump exists between elevations of 325 and 425 feet on the right abutment upstream from the axis. Here the more brittle Vaqueros sandstone has slumped slightly out of 4-21 position, possibly due to yielding of the less competent underlying beds. The slide comprises about 50,000 cubic yards of material. Most of this material exposed by the aforementioned tunnels appears to be reasonably firm and stable, although a final decision as to its suitability for foundation necessarily would have to await final stripping. From examination of the material exposed in cores, tunnels, and on the surface, it does not appear that the foundation area would accept much grout, unless large unknown seams or cavities are encountered during stripping operations. As the ridge forming the left abutment is rather thin, leakage from the reservoir could result unless the upstream slope was blanketed with impervious material. Major faulting at the site was not observed or indicated by explora- tion work. However, it is apparent that numerous small faults and possibly shear zones exist in the foundation area. Others may come to light with addi- tional exploratory work, particularly in the channel section. While a small amount of shaping may be necessary in the developed foundation, no serious defect is believed to exist. Since the Casitas dam site lies in a moderately seismically active area, proper consideration of this factor should be given in the design of any structure at this site. Operation and Yield of Reservoir. As was stated, consideration was given to utilization of a reservoir at the Casitas site not only for impounding runoff in Coyote Creek but also for offstream storage of surplus waters diverted from the Ventura River. Diversion sites studied in this regard were located so as to enable capture both of flow in the North Fork of Matilija Creek and spill from Matilija Reservoir. Table 51 presents seasonal base period values of estimated runoff of Coyote Creek at the Casitas dam site, measured runoff of the North Fork of Matilija Creek, and estimated spill from Matilija Reservoir operated to give a gross seasonal yield of 3,700 acre-feet. Runoff of Coyote Creek at the Casitas dam site was estimated to be 90 per cent of measured U-22 runoff at the U.S.G.S. stream gaging station on Coyote Creek near Ventura, TABLE 51 SEASONAL RUNOFF OF COYOTE CREEK AT CASITAS DAM SITE AND NORTH FORK OF MATILIJA CREEK, AND SEASONAL SPILL FROM MATILIJA RESERVOIR, DURING BASE PERIOD (In acre-feet) Season Coyote Creek at Casitas dam site* North Fork of Matilija Creek near Matilija Spill from Matilija Reservoir* 1936-37 1937-38 1938-39 1939-UO 20,060 23,900 2,700 2,190 13,590 22,920 2,7i|0 2,250 U0,h30 77,230 9,600 5,300 19UO-U1 I9I4I-U2 19U2-U3 • • 19U3-UU • 19UU-U5 U5,8oo 3,270 26,020 13,670 6,550 31,290 U,300 15,970 9,870 U,820 120,260 9,630 55,290 33,650 11,060 19U5-U6 19U6-U7 19U7-U8 19W-U9 19U9-50 3,2U0 2,550 50 130 1,320 5,150 3,000 760 1,150 1,630 1U,270 6,260 1950-51 90 . 590 TOTALS 151,530 120,030 382,980 AVERAGES 10,100 8,000 25,530 * Estimated. As a first step in the analysis of Casitas reservoir, estimates were made of the amounts of water susceptible to diversion from the Ventura River with works having capacities of from 50 to 200 second-feet, in increments of 50 second-feet. By analyzing daily records of runoff in the North Fork of Matilija Creek and estimates of daily rates of spill that would have occurred from Matilija Reservoir during the base period, the amounts of water that could U-23 have been diverted to Casitas Reservoir for each of the conduit capacities were determined. Neglecting for the moment prior rights to Ventura River water below the point of diversion to Casitas Reservoir, the water available for such diver- sion would have included all spills from Matilija Reservoir plus the entire runoff of the North Fork of Matilija Creek. The seasonal amounts of water that could have been so diverted to Casitas Reservoir during the base period, by the four capacities of diversion conduit and with Matilija Reservoir in operation, are presented in Table 52. TABLE 52 ESTIMATED SEASONAL POTENTIAL FOR DIVERSION OF WATER FROM VENTURA RIVER TO CASITAS RESERVOIR DURING BASE PERIOD VilTH MATILIJA RESERVOIR IN OPERATION AND WITHOUT PROVISION FOR DOWNSTREAM RIGHTS (In acre-feet) : Capacity of diversion conduit, in second-feet Season : 50 : 100 ! 150 200 1936-37 1937-38 1938-39 1939-UO 15,920 18,500 10,090 6,000 2li,960 28,li90 11,500 6,910 30,890 35,UlO 12,160 7,150 35,000 ho ,690 12,3llO 7,21*0 19U0-iil 19lil-U2 19h2-h3 19h3-hh !9hh-hS 23,700 11,710 111, 960 15,920 10,370 38,790 12,600 23,000 21,630 11,550 li9,780 12,960 28,590 25,520 12,100 59,150 13,260 32,900 28,lilO 12,500 19U5-U6 19U6-U7 19ii7-U8 19U8-U9 19ii9-50 9,020 6,li30 760 1,150 1,610 10,670 7,220 760 1,150 1,630 11,530 7,600 760 1,150 1,630 12,31*0 7,890 760 1,150 1,630 1950-51 ' 590 590 590 590 TOTALS lli6,730 201,1*50 237,820 265,850 AVERAGES 9,780 13,U30 15,850 17,720 ll-211 By combining estimated values of diversions of Ventura River water for each of the four conduit capacities with estimated values of runoff in Coyote Creek at the dam site, total monthly inflows to.Casitas Reservoir were determined. From these estimates, mass diagrams of cumulative monthly inflow were plotted. Graphic analysis of the mass diagrams indicated the variation in reservoir yield with storage capacity for each of the four diversion capa- cities considered, up to the maximum capacity of Casitas Reservoir required to regulate each of the diversions. Yields indicated on the mass diagrams were corrected to take into account evaporation losses. This was done making operation studies of the selected reservoirs on a monthly basis throughout the base period. An estimated average depth of net seasonal evaporation of 2.00 feet, distributed monthly in accordance with the following tabulation, was employed in the operation studies: Net evaporation, Net evaporation, Month in feet of depth Month in feet of depth October 0.20 April 0.15 November 0.09 May 0.20 December 0.05 June 0.25 January o.oU July 0.28 February 0.05 August 0.30 March 0.11 September 0.28 TOTAL 2.00 By the same method yields from the mass diagrams were further re- duced by the amounts of rights to water of users downstream from the diversion point on the Ventura River. These rights were estimated as the reduction resulting from the diversion in the amounts of water that would otherwise have been available for beneficial use below the diversion point. The estimated average seasonal amounts of the rights are set forth in the following tabulation: U-25 Estimated rights of downstream users to waters of Ventura River Capacity of otherwise available diversion works, for diversion, in second-feet in acre-feet per season 50 2,U50 100 2,800 i£o 3,000 200 3,0^0 In all reservoir operation studies of Casitas Reservoir, an allowance was made for loss of effective storage capacity by sedimentation in the amount of 2,000 acre-feet. This value represents the estimated loss after about 20 years of operation. It was found that the series of wet years from 1936-37 through 19U3-UU would have filled Casitas Reservoir by the spring of 19UU to all storage capacities considered, and that the reservoir would have been drained in the fall of 193>1» Presented in Table £3 are the estimated storage capacities required to completely regulate runoff in Coyote Creek plus inflow from the Ventura River with the four capacities of diversion conduit considered. The table also shows the estimated net safe seasonal yields that would result from construction of the indicated developments. 4-26 TABLE 53 ESTIMATED STORAGE CAPACITIES AND NET SAFE SEASONAL YIELDS OF CASITAS RESERVOIR FOR VENTURA RIVER DIVERSION CONDUIT OF VARIOUS CAPACITIES Capacity of diversion conduit, in second-feet Gross reservoir storage capacity required for complete regulation, in acre-feet Net safe yield, in acre-feet per season 0* 50 100 150 200 65,000 8,400 105,000 15,200 130,000 18,300 145,000 20,200 156,000 21,900 * With use of Coyote Creek water alone. Rough analysis of earlier drought periods indicated that, with the ex- ception of the 156,000 acre-foot capacity reservoir, the drought period from 1944-45 through 1950-51 was the most severe in regard to yield for all reservoir storage capacities studied. Had a Casitas Reservoir with capacity of 156,000 acre-feet, augmented by a 200 second-foot diversion from the Ventura River, been in operation during the critical water supply period from 1922-23 through 1935-36, it was estimated that the yield shown in Table 53 would have been reduced about 1,000 acre-feet per season. The operation studies indicated that little increase in yield would be obtained for any given size of reservoir by increasing the capacity of the diver- sion conduit, unless the reservoir storage capacity exceeded that required for complete regulation of inflow. However, it was found that there was a relatively small difference in estimated costs of constructing conduits of varying capacities up to 200 second- feet, as hereinafter described. For this reason, it was concluded that a conduit with 200 second-foot diversion capacity should be provided, to 4-27 assure filling of Casitas Reservoir during water supply periods with different regimens of flow than that of the base period and with possible longer and more deficient periods of drought. Table 54 presents estimates of the combined monthly inflow to Casitas Reservoir during the base period with a conduit capacity of 200 second-feet. 4-28 -4 ir\ g en B I 0) o •p ay en ft 9 o ocio vO 0\-5fcn O T-^O -4" #t *v *\ •* ir\ -4 ir\ o i^^ h o qo q ITS -4"sO -4 H en O O O Q o o o -4 en^O o o o o O CM i>nO C~- CM o o o o HrHAN H CNi Q Q o o I> irwo -4 en -4 Q Q Q. 9 cm o cm o O CO H O O O Q -4C-0 Q O -40 -4 O O O O O m en CM to tr\ O ir> o O O -4nO to CM On m O O H m -4 t-l H H o o o o o wr\ -4- to CM O its o H CM -4CM O O O Q -4 H 0-4" OvO CM -4 H H O O O Q QOto4 OOCMA CM H CM O O O O CM vO Uf\ O -cf ir\ ir\ CM CM H CM O O O O O CM CO vO nO to O H t-l O O O O UN CM CM O O O O O H -40 CM vO £> H ITWO r-l CM O O O Q Q OrH cn-4 -J CM m en -4 -4 O O O O O (><0>0^ O m O C*» o enC- m O en O en m -* CM CM O O O O O -4 cno cnE> O m H ^O -4- •\ «> #k ^ •% OvHCM^- enen en m O O O Q O o -4 cm ~4 en o o o o o ~4 en in m o o o o 00 -4 O O- CM m O O Q O CM m -4 >0 H H -4 o-to o q men en-"?" i I I i sO O- tO O en en en en o o o o r-\ r-i H r~\ O rH H H rH 3 o o o o o .j- o in ir\vO O inO vO r- «\ *s ^ *» H CM t>- H O O O O O H C)H to in O CO a a i i i i. o o o o o -4 r-vo o o o o o o o o cm o in r>- -4 H H H H O O O O Q CM CM -4 in -4 vO -4 H H CM O O O O O into -4 m m o to h en en -4 en O O O O Q sO O O O -4 O H CM O O O O O ir\ itn o into O rH H H CM en -4 in -4-4-4-4-4 CM o o o o q o en to o^o -4- <-\ en H H O O O O O IT\ Qv^O CM O -4 en H CM CM O OJ CO t> CM O CM O -4 O o r- o o o CO O o o o o q q vO to vO H O C^vO rH CM cm en O O O O O O o->vO in in c~- ir\ O P- 6 rH cm en -4 -4 -4^t ^-^ O O O O CJn ,-\ r4 r-\ <-\ r-\ o o o oo O to -4 -4 m vO P- to C> O I I I I I ITNsO C- tO 0> _j- -4 ^t -4 -4 O O O O O r-\ H H rH rH o WTN H in I o ir\ o H H in A in o H ■a O ?-i jc! ■P o- en en •H H nJ C O (0 nJ 0) (0 CD nJ u CO 5 4-29 Estimates of the net safe seasonal yields that could be obtained vdth selected storage capacities of Casitas Reservoir, and with the 200 second-foot capacity diversion conduit, are shown in Table 55. TABLE 55 ESTIMATED NET SAFE SEASONAL YIELDS OF CASITAS RESERVOIR FOR SELECTED STORAGE CAPACITIES, WITH 200 SECOND-FOOT VENTURA RIVER DIVERSION CONDUIT (In acre-feet) Reservoir storage capacity : Net Gross : Net : safe yield 92,000 90,000 14,000 105,000 103,000 15,600 130,000 128,000 18,600 156,000 154,000 21,900 Design Features of Ventura River-Casitas Diversion. Investigation was made of three possible sites for weirs to divert Ventura River water to Casitas Reservoir. The uppermost of the three sites considered is on the North Fork of Matilija Creek about e 6 mile above its confluence with Matilija Creek. Diversion at this site would involve conveying a portion of the North Fork flow through a tunnel into Matilija Reservoir, with release from that reservoir conveyed through a conduit to Santa Ana Creek, a tributary of Coyote Creek above Casitas Reservoir. The middle of the three sites considered is located immediately downstream from the confluence of the North Fork and Matilija Creek, and the diversion would in- clude a conduit leading to Santa Ana Creek over a portion of the route of the preceding alternate. The lowermost of the three diversion sites studied is about 1.3 miles downstream from the confluence of the North Fork and Matilija Creek, and about one mile upstream from Meiners Oaks. The conduit to Santa Ana Creek 4-30 from this site would also be aligned over a portion of the route utilized by the preceding alternatives. Estimates of cost for diversion works and conduits with capacities of 100 second-feet, 150 second-feet, and 200 second-feet, for each of the three sites, indicated that use of the middle site would be slightly more economical than the others, This fact, together with minor favoring engineering considerations, resulted in choice of the middle site for further study. As previously mentioned, a large diversion capacity may be needed in the future to assure filling of Casitas Reservoir under certain conditions of water supply. For this reason a diversion conduit from the Ventura River of 200 second-foot capacity was selected for cost analysis. Preliminary designs for the diversion conduits and estimates of con- struction quantities were made from a profile prepared by the Ventura County Flood Control District in 1951j at a horizontal scale of one inch to 1,000 feet, and a vertical scale of one inch to 20 feet. Alignment and grade for those portions of the conduits above the limit of the County's location survey were determined by use of United States Geological Survey topographic maps at a scale of 1:24,000, and from information obtained during a field reconnaissance. Preliminary esti- mates of construction quantities for the diversion weirs were obtained from pro- files at a scale of one inch equals 20 feet, both horizontally and vertically, prepared from field surveys by the Division of Water Resources. The proposed diversion weir at the middle site v/ould be of the concrete overpour type with ogee section, founded on bedrock at a stream bed elevation of 900 feet. The weir would be 10 feet in height above stream bed, and would be about 170 feet in length. Water would be diverted over a parapet wall into a side channel diversion box, and thence into a sand trap. From the sand trap, water would discharge either into a reinforced concrete pipe, 54 inches in diame- ter, or via sluiceways into the Ventura River, The pipe line would parallel the Ventura River on its right bank southerly for a distance of about 17,600 feet to 4-31 a point west of Meiners Oaks, where it would discharge into a canal. The canal would extend about 14,730 feet southwesterly to discharge into Santa Ana Creek, about 3.5 miles upstream from the Casitas dam site. Included in the length of canal would be two flumes, comprising a total length of about 63O feet . The canal would be shotcrete lined, and would have a 5-foot bottom width, 1.5:1 side slopes, and a depth of water of 3.2 feet, with a freeboard allowance of 1.0 foot. The slope of the canal would be 0.002, and the velocity of water flowing therein at design capacity would be 6.4 feet per second. The two flumes would be of metal construction, 8.3 feet and 8.9 feet in diameter, and with slopes of 0.0022 and 0.0014, respectively. The location of the proposed diversion weir at the middle site, and of the approximate alignment of the conduit are shown on Plate 42, entitled "Proposed Conveyance and Distribution Systems". General features of the Ventura River-Casitas Diversion are presented in Table 56. 4-32 TABLE 56 GENERAL FEATURES OF VENTURa RIVER-CASITAS DIVERSION WITH CAPACITY OF 200 SECOND-FEET Diversion Weir Type Concrete gravity weir, with ogee overpour section; side channel diversion box, with overpour parapet wall, and 5 by 5 foot slide headgates in concrete headwall, and 5 by 5 foot slide sluicegate. Crest elevation, in feet, U.S.G.S. datum 910 Height of weir above stream bed, in feet 10 Length of weir, in feet. 170 Diversion Conduit Pipe Line Type 54-inch diameter, rein- forced concrete Length, in feet 17,600 Canal Type Trapezoidal, shotcrete lined Length, in feet 14,100 Side slopes 1.5:1 Bottom width, in feet 5.0 Depth of water, in feet 3.2 Freeboard, in feet 1.0 Slope 0.002 Velocity, in feet per second 6.4 Flumes Type Lennon metal flume - semi- circular section Length, in feet 600 30 Diameter, in feet 8,3 8.9 Freeboard, in feet 0.50 0.54 Slope 0.0022 0.0014 Velocity, in feet per second 9.1 7.6 4-33 Design Features of Casitas Dam and Reservoir. As a result of the pre- viously described geologic investigation and yield studies, preliminary estimates of cost were made for dams at the Casitas site of 178 feet, 188 feet, 202 feet, and 215 feet in height from stream bed to spillviay lip, creating reservoir storage capacities of 92,000 acre-feet, 105,000 acre-feet, 130,000 acre-feet, and 156,000 acre-feet, respectively. For all heights of dam, a rolled fill structure was con- sidered, comprising an upstream impervious section of select earth material with a downstream section of random earth material. Both upstream and downstream slopes of the dams would be 3:1, with a slope of the downstream face of the impervious section of 1:1. Crest widths for the dams would be 25 feet. Random material was chosen for downstream sections rather than pervious fill because of the absence of suitable permeable material in the area. Utilizing random fill would require installation of gravel drains to remove any small amount of leakage that might occur through the impervious section. A gravel blanket, with a thickness of 6 feet normal to the downstream slope of the impervious fill, would be placed at the con- tact between the impervious and random fill, and would extend to a height of two- thirds of the distance betiveen stream bed and spillway lip. Placing the gravel blanket to this height should amply cover that" portion of the face of the imper- vious fill within the zone of saturation. Seepage intercepted by the blanket would be discharged into four longitudinal gravel drains extending to the toe of the random fill. These drains would be about 6 feet in thickness and 15 feet in width, and would be placed along each abutment and at one-third points across the stream bed. The upstream slope of the dam would be protected against wave action by placement of riprap to a depth 3 feet normal to the slope. The downstream slope of the random section would be stabilized and protected against the erosive action of rainfall by finishing off with topsoil, rolling in barley straw, and planting of bacharis shoots. Horizontal gutters, paved with cobbles, would be pro- vided at 30- foot vertical intervals. 4-34 It was assumed that about 50 feet of alluvial sand and gravel would have to be stripped from under the impervious section. Under the random section in the stream bed, stripping depth was estimated to be 5 feet. Stripping requirements on the left abutment were estimated to be on the order of 10 feet under the imper- vious section, and 5 feet under the random section. On the right abutment, strip- ping would average about 20 feet under the impervious section and about 10 feet under the random section. For estimating purposes for all heights of dam considered, it was assumed that the slide existing between elevations of 325> and hZ$ feet in the right abutment would be removed in its entirety, thereby adding about 50,000 cubic yards to stripping requirements. It was estimated that about 80 per cent of foundation stripping would be used for random fill, thus reducing required borrow. Field investigation indicated that sufficient borrow for the impervious fill could be obtained within a distance of about 3*000 feet from the site. Stripping excavation quantities were divided into common and rock classifications, in order to take advantage of the lower unit costs for excavation of large volumes of common material with tractor-drawn scrapers. It was assumed that rock excavation in the stream bed would consist of dressing- up the foundation surface with power shovels, bulldozers, or rooters. Foundation treatment would also include moderate grouting to insure against excessive seepage. Stripping of abutments would involve excavation of soil and solid rock in moderate quantities, and/or broken rock in relatively large quantities. It was assumed that both im- pervious and random material would be placed with the tractor-drawn scraping equipment and compacted with sheepsfoot tampers. Gravel for the drains and pervious blanket would probably have to be imported from the S^nta Clara River near Saticoy, about 20 miles in distance. The nearest known source of rock for riprap is near Matilija Dam, which is about 11 miles from the site. Access to the site during and after construction could be maintained via the Casitas Pass Road. U-35 It is indicated that excessive leakage might occur through the rela- tively thin rib that forms the left abutment of the Casitas dam site, and that it might be necessary to place an impervious blanket on the upstream slope of this rib. Provision for such a blanket was not included in the estimates for the 92,000 and 105,000 acre-foot reservoirs, it being assumed that if substantial leakage were observed after construction the reservoir could be drawn down and the blanket placed at that time. For the 130,000 and 156,000 acre-foot reser- voirs, dam axes were moved a short distance upstream, and blanketing of both the left and right abutments was effected by impervious fill of the dam. Spillways for all heights of dam considered would have a discharge capacity of 17,000 second-feet, which is the estimated peak discharge of a once in 1,000-year flood. The spillways were desiged as overpour chute types, with ogee weirs, concrete lined, and founded on bedrock in the left abutment. The designed maximum depth of water above the spillway lip varied from 9.4 to 11.0 feet for the several sizes of dam, and the residual freeboard comprised the re- maining distance to the dam crest, which was 20 feet above the spillway lip. For the dam creating a reservoir of 92,000 acre-feet capacity, the spillway would be located in a saddle about 1,600 feet east of the center line of the stream channel. For the 105,000 and 130,000 acre- foot reservoirs, a saddle about 1,000 feet further east would be employed, whereas the spillway for the 156,000 acre-foot reservoir would be constructed about 400 feet still further to the east. In the selection of spillway sites, consideration was given to utili- zation of a saddle in the reservoir rim, through which the Santa Ana Road enters the reservoir area, where spill could be discharged directly into the Ventura River. Preliminary estimates of cost indicated that this site did not compare favorably with the sites chosen. Outlet works would be located in a circular reinforced concrete tower, located upstream from the dam on the right abutment, varying in diameter and 4-36 leight in accordance with the considered height of dam. Water would enter the iower through six gate valves, which would also vary in diameter in accordance tith the considered reservoir capacity. Intake to the tower would be conveyed beneath the dam in a reinforced concrete cylinder pipe. The pipe would be encased fin concrete and placed in a trench excavated in the foundation along the right abutment. Placing the outlet pipe on this abutment would be contingent upon find- ing satisfactory foundation conditions after removal of the aforementioned slide. "For the 92,000 and 105,000 acre-foot reservoirs, 42-inch diameter outlet pipes were assumed, with 48-inch diameter pipes employed in the estimates for the two larger reservoirs considered. The outlet conduit would feed into a. control house where a bifurcation structure controlled by gate valves would be placed, thereby allowing water discharged from the reservoir to enter either Coyote Creek or into the proposed distribution system. It was estimated that two years would be required for construction of the 92,000 acre-foot and 105,000 acre-foot reservoirs, three years for the 130,X)00 acre-foot reservoir, and four years for the 156,000 acre-foot reservoir. It was assumed that the construction schedule would be arranged so that the embankment would be placed to stream bed level prior to the first winter season. Runoff dur- ing the first season would be passed over the embankment in a channel 50 feet in width, constructed along the right abutment. Outlet works would be constructed during the second working season. For the two dams requiring in excess of two years to complete, it was assumed that the embankment would be high enough during the second winter season so that sufficient storage would be available to handle floods of record, and that releases could be effected through the outlet works. From study of aerial photographs, it was concluded that clearing of trees and brush would be required from about one-half of the Casitas reservoir area, or from about 800 to 1,000 acres. Approximately 3.5 miles of State Highway 150, and 4-37 about 2.0 miles of county road would require relocation. Provision was made for a service road on the easterly side of the reservoir area. Relocation of certain other utilities also would be required, including a power line of the Southern California Edison Company. About 4,300 acres of privately owned lands and improvements would have to be acquired. Estimates of costs for relocating State Highway 150, the county road, for acquisition of reservoir lands and improvements, and for relocation of utilities were made in 1951 by the Ventura County Flood Control District. A revised estimate of the cost of acquisition of lands and improvements was fur- nished by the Ventura County Flood Control District in 1953. Pertinent data with respect to general features of the four sizes of dam and reservoir considered at the Casitas site, as designed for cost esti- mating purposes, are presented in Table 57. For illustrative purposes, a plan, profile, and section for the dam creating a reservoir with a capacity of 130,000 acre-feet are shown on Plate 26, entitled "Casitas Dam on Coyote Creek'J. 4-38 TABLE 57 GENERAL FEATURES OF FOUR SIZES OF DAM AND RESERVOIR AT THE CASITAS SITE ON COYOTE CREEK Earthf ill Dam Crest elevation, in feet, U.S.G.S. datum 523 533 Shi 560 Crest length, in feet 1,665 1,695 2,5UO 3,970 Crest width, in feet 25 25 25 25 Height, spillway lip above stream bed, in feet 178 188 202 215 Side slopes, upstream and downstream. . . 3*1 3:1 3*1 3il Freeboard above spillway lip, in feet 10.6 9 9 8.5 Elevation of stream bed, in feet, U.S.G.S. datum. . . 325 325 325 325 Volume of fill, in cubic yards .... U,7l5,UOO 5,U6l,800 6,93U,100 12, Ula, 800 Reservoir Surface area at . spillway lip, in acres ........ 1,375 1,53Q 1,790 2,000 Gross storage capa- city at spillway lip, in acre- feet 92,000 105,000 130,000 156,000 Type of spillway . . Ogee weir and Ogee weir and Ogee weir and Ogee weir and concrete lined concrete lined concrete lined concrete lined chute chute chute chute Spillway discharge capacity, in. second-feet ...» 17,000 17,000 17,000 17,000 Type of outlet ... Concrete tower Concrete tower Concrete tower Concrete tower with [£-inch with. 14.2-inch with li8-inch with 14.8-inch diameter rein- diameter rein- diameter rein- diameter rein- forced con- forced con- forced con- forced con- crete cylinder crete cylinder crete cylinder crete cylinder pipe beneath pipe beneath pipe beneath pipe beneath dam, encased dam, encased dam, encased dam, encased in concrete in concrete in concrete in concrete h-39 Summary of Estimated Costs. Presented in Table 58 is a summary com- parison of capital and annual costs of the four considered sizes of dam and reser- voir at the Casitas site, and of the Ventura River-Casitas diversion with a capacity of 200 second- feet. Also presented in Table 58 are estimated unit costs of storage capacity and net safe yield of water that would result with construction of the indicated works. Certain of these latter relationships are depicted gra- phically on Plates 35, 36, and 37. Detailed estimates of cost for the four sizes of dam and reservoir, and for the Ventura River-Casitas diversion works and conduit, are presented in Appendix C, TABLE 58 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE CASITAS SITE ON COYOTE CREEK, WITH DIVERSION FROM VENTURA RIVER OF 200 SECOND-FOOT CAPACITY : Reservoir storage c apacity, in acre-feet Item : 92,000 : 105.000 : 130,000 : 156,000 Capital Costs Dam and reservoir $ 3,938,000 $ 9,678,000 $ 11,763,000 $19,636,000 Ventura River- Casitas diversion 1,112,000 1,112,000 1,112,000 1,112,000 Totals 10,050,000 10,790,000 12,875,000 20,748,000 Cost per acre-foot of storage capa- city 109 103 99 133 Cost per acre-foot of net safe yield 718 692 692 947 Annual Costs Dam and reservoir $467,000 $507,000 $615,000 $1,017,000 Ventura River- Casitas diversion 60,000 60,000 60,000 60,000 Totals 527,000 567,000 675,000 1,077,000 Costs per acre-foot of net safe yield 38 36 36 49 Cost per acre-foot of incremental net safe yield 25 36 121 4-40 Ferndale Dam and Reservoir . The Ferndale dam site is located on Santa Paula Creek about 0.4 mile southeast of its confluence with Sisar Creek, a principal tributary, and in Section 16, Township 4 North, Range 21 West, S.B.B. & M. State Highway 150, paralleling Santa Paula Creek, passes along the right abutment of the dam site, and traverses a portion of the reservoir area. Stream bed elevation at the dam site is about 910 feet, U.S.G.S. datum. Consideration was given to the construction of a dam and reservoir at the Ferndale site for storage of flood waters in Santa Paula Creek, and utilization of the waters so conserved in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. The drainage area of Santa Paula Creek above the Ferndale dam site comprises about 36 square miles, and produced an estimated average seasonal runoff during the base period of about 15,700 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 12,000 acre-feet per season during the base period with the present pattern of land use and water supply development. The Ferndale dam site was mapped up to an elevation of 1,225 feet in August, 1951, by the Ventura County Flood Control District, at a scale of one inch equals 200 feet, with a 5-foot contour interval. Reservoir areas and capacities for various heights of dam were obtained from available advance sheets of U.S.G.S. quadrangles, at a scale of 1:24,000 with a 20-foot contour interval. Storage capacities of Ferndale Reservoir at various stages of water surface elevation are given in Table 59. U-lil TABLE 59 AREAS AND CAPACITIES OF FERNDALE RESERVOIR t Water surface • « • • Depth of water t elevation, : Water surface : Storage capacity, at dam, in feet* U.S.G.S. datum, t area, in acres : in acre-feet • • in feet • * « • 910 10 920 5 15 20 930 7 75 30 9U0 9 155 ko 950 12 260 50 960 15 390 60 970 26 600 70 980 37 910 80 990 U7 1,330 90 1,000 58 1,850 100 1,010 78 2,530 110 1,020 99 3,U00 120 1,030 120 U,500 130 l,0l|0 lltO 5,800 lho 1,050 160 7,310 i5o 1,060 185 9,050 160 1,070 210 11,000 165 1,075 220 12,100 170 1,080 230 13,200 180 1,090 250 15,600 190 1,100 270 18,200 200 1,110 290 21,000 210 1,120 310 2l|,000 220 1,130 330 27,200 230 i,iUo 350 30,600 2U0 i,i5o 380 3U,200 250 1,160 UOO 38,100 260 1,170 U30 U2,300 270 1,180 U5o U6,700 280 1,190 U80 51,300 290 1,200 510 56,300 Mi2 A geologic investigation of the Ferndale dam site was made in 1951 by- geologists of the Division of Water Resources. No prior geologic work at this site is known, nor has the site been drilled. Available information indicates that the site is suitable for construction of an earthfill or rockfill dam up to a maximum height of about 27O feet. Formations at the dam site consist mainly of shale of the Modelo formations and extensive unconsolidated terrace deposits. Upstream from the site, Rincon shale, Pico sediments, Matilija sandstones, and Cozy Dell shale were noted, while Santa Margarita sandstone is in evidence immediately down- stream from the site. Terrace deposits occur at various levels, varying from poorly stratified to unstratified in character, and apparently include old stream deposits, land slide, and colluvial material. Most of the terrace deposits contain many pebbles and cobbles, and in the case of the higher terraces include subangular blocks. The amount of fines in the terraces varies considerably, from limited quantities to instances where the amount of such binder material is appreciable. The shale exhibits considerable contortion and folding, with the strike varying from about North 60 degrees East to North 80 degrees East, and with a dip varying from about 55 degrees east to steep overturned dips to the southeast. A zone of thick colluvial cover, land slide material, and extensive travertine deposits occurs on the right abutment up- stream from the dam axis. Two major faults were identified in the vicinity of the site, together with a number of minor faults and shears. A fault trending about North 80 degrees East crosses Santa Paula Creek about 1,000 feet downstream from the dam site. The San Cayetano fault has been mapped, trending in a east-west direc- tion about 1,500 north of the site. However, the Ferndale dam site appears to be free from major faults, so far as could be determined. Based on estimates of runoff during the base period, yield studies U-i*3 were made for reservoir storage capacities at the Ferndale site of 12,000 acre- feet, 2U>000 acre-feet, and 3U,000 acre-feet, respectively. Runoff at the site was estimated to be 92 per cent of measured runoff at the U.S.G.S. stream gaging station on Santa Paula Creek near Santa Paula. Estimated monthly runoff of Santa Paula Creek at the Ferndale dam site during the base period is presented in Table 60. U-14i n o N w PL, w en o s M Q to 1 pq w o 3 P-4 CO Cm o ft. ClH o C£ Eh I Q I Eh CO +3 CD CO tH I CO U O crj o Eh c, CO b) Pi P. Ix a a > c c o o o o vO o o o cntO £>■ O- #i v\ *\ r\ oo c- -4 CM -4 o o o o CM en -4 O O O O to c- lt\ r- o o o o tO CM O tO -4 O CM O O Q O -4 cn-4 O M>Nrl o o o o nO o to o VNnO P"\ Cn H H o o o o vO CM in^A to O C^-'A Cn O O H Q O O O H OiA^ CMArl 'A •» »\ rH rH o o o q O m -4 H en OvO CM O Q O O N 400 CM CM en H o o o o O nO H O -t CM cn H o o o q q to nO u^v -4 H O CA'A^O CV cnvO nO O rH \S\ cn CM H O O O O O H O CM CO no o o o o q lAOOWOO sO enCM CM o o o o o vOtOtAQ® O HIA-4CM o o o o o O >n - 'nO wn O O O O O sO H CM J>-^0 cr\ H H o o o o o H H C"- cn <> H »N »\ «\ «N H rH CM CM H O O O O O O rH tO «TNsO H u-\ £> CM -4 O H rH to CM O O O O O ^tlAtO C-^ H u> to O CM •4 «\ •» *> o o o Q q lAOllAOO r>- o o to -4 CM H O O O O O O en H O -4 o o o o o H CAH CAO o o o o o O CO r-j O O rH -4 r-i en CM o o o o q O 4 1 s - CM H CM r- u^ to CM •* *\ *\ •% ^ o o o o o CM O -4 CM tO CM - tO O O -4-4 -4 -4 lt\ I I I I I i^nO O- tO O -4-4-4-4-4 O O O On O <-\ r-\ r-1 r-\ r-1 H 6 o H CO bO crj U 5 U-U5 In all of the studies an allowance was made for reduction in effective reservoir storage capacity due to sedimentation, in the amount of 2,000 acre-feet. This amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 1.70 feet, distributed monthly in accordance with the following tabula- tion, was employed in the operation studies. Month October November December January February March Total 1.70 Monthly studies of operation of Ferndale Reservoir during the base period were made for the three sizes of reservoir considered under both the uniform release and rapid release methods of operation. The estimated values of net safe seasonal yields that would be obtained under both the uniform release and rapid release operating criteria are presented in Table 6l. The relationship between reservoir storage capacity and net safe seasonal yield, with Ferndale Reservoir operated by the uniform release method and with releases for maintenance of water levels in Santa Paula Basin, is depicted graphically on Plate 36. Net evaporation Month Net evaporation. in feet of depth in feet of depth 0.15 April 0.15 0.06 May 0.19 0.04 June 0.21 0.04 July 0.25 0.05 August 0.25 0.10 September 0.21 hrh6 TABLE 61 ESTIMATED NET SAFE SEASONAL YIELDS OF FEjM)AL£ RES.ERVQIR (In acre-feet) ; Unirorm re lease operation t Rapid release operation" : Available to Oxnard t Available to Oxnard « t U,000 2,500 2,000 6,500 l»»900 5,000 8,500 6,700 14,200 Reservoir storage : Forebay, Oxnard ; Forebay, Oxnard s « Available to Oxnard capacity 1 Plain, and Pleasant « Plain, and Pleasant t Available within s Forebay, Oxnard 1 Valley Subunits, « Valley Subunits, 1 Santa Clara River « Plain, and Pleasant 1 with releases for 1 without releases : Hydrologic Unit » Valley Subunits j maintenance of » for maintenance of » : ; ground water levels t ground water levels t « 12,000 2,500 214,000 U,900 514,000 6,600 As a result of the geologic investigation and the reservoir yield studies, estimates of cost were prepared for dams at the Ferndale site with heights of 165 feet, 210 feet, and 2)40 feet from stream bed to spillway lip, creating reservoir storage capacities of 12,000 acre-feet, 2ii,000 acre-feet, and 3Uj000 acre-feet, respectively. For all heights of dam, a rolled fill structure was contemplated, comprising an impervious core of select earth material, and upstream and downstream sections of pervious free draining material. Both upstream and downstream slopes of the dam would be 2.5:1 for the dams of 165-foot and 210-foot height, and 3:1 for the dam of 2ii0-foot height. The impervious sections would have upstream and downstream slopes of 1:1. Crest widths would be 30 feet, comprised of a 10-foot width for the im- pervious core, and 10-foot widths each for the upstream and downstream pervious sections. The upstream face of the dam would be protected against wave action by rock riprap placed to a depth of 3 feet normal to the slope. In the cost estimates, it was assumed that a depth of about 8 feet of sand and gravel would be stripped in the channel under the impervious core. On the left abutment, depths of from 5 to 50 feet of terrace material and from h to 6 feet of fractured shale would be removed. Under the impervious section on the right abutment, stripping requirements were estimated to comprise a depth of about 2 feet of surface soil, plus an average depth of about 12 feet l*-U7 of fractured shale. The cost estimates do not include provisions for removal of the aforementioned land slide and colluvial material from this abutment. Further exploratory work and examination during construction would be required to indicate the amount of additional stripping needed in this area. For the pervious sections, a nominal depth of stripping of 2 feet was assumed through- out the contact area. During actual construction, increased stripping might be required under the pervious sections of the dam to stabilize slopes, par- ticularly in the land slide area on the right abutment. It was assumed that foundation treatment would include moderate grouting. It is indicated that adequate material for the impervious section of Ferndale Dam is available within one mile upstream and downstream from the site. In this connection, it was assumed that terrace material stripped from the left abutment would be almost entirely usable in the impervious section. Two samples of material, taken from other possible borrow areas, were tested by the Division of Water Resources and were deemed adequate for use in the im- pervious section. Sufficient borrow material suitable for the pervious sections of Ferndale Dam is likewise available within about a mile of the site. It was estimated that a portion of the material stripped beneath the impervious sec- tion, and too coarse for use therein, would be used in the pervious sections. Matilija sandstone, outcropping about one mile upstream from the site, could be quarried for riprap. It was assumed that compaction of the impervious section of the dam would be effected by either sheeps-f oot tampers or pneu- matic rollers, and that pneumatic rollers would be used to compact the pervious section. Spillways, for all heights of dams considered, would have a discharge capacity of 37*000 second-feet, which is the estimated peak discharge of a once in 1,000-year flood. The spillways were designed as concrete-lined over- pour chutes, with ogee-weir control sections. For the two smaller dams, the spillway weir and chute channel would be excavated across the terrace easterly U-U8 on the left abutment, and would discharge into a small ravine a short distance downstream from the dam. For the largest of the dams considered, topographic considerations required that the spillway be located across the right abutment. Depth of water above the spillway lip at design discharge capacity would be 20 feet for the dam of 165 foot height, and 25 feet for the dams of both 210 and 2l|0 foot height. A depth of 5 feet of residual freeboard was provided in the spillways for each of the three heights of dam. As it was estimated that the dam of 165 foot height could be construc- ted in one year, it was assumed that diversion of summer flow in Santa Paula Creek would be effected through the outlet conduit. For the dams with heights of 210 and 2^0 feet, requiring an estimated two years for construction, it was assumed that a 15-foot diameter concrete lined tunnel of horseshoe section would be constructed through the right abutment to provide for diversion of winter flows. The tunnel would be about 1,250 feet in length for the smaller dam and about 1,600 feet in length for the larger. It was assumed that outlet works for both of the larger dams would utilize the diversion tunnel after construction. The approach channel for the outlet works would be 100 feet in length, with a varying bottom width and 1:1 side slopes. Maximum depth of cut would be about kO feet. A submerged concrete intake structure would be located immediately upstream from the tunnel portal. This structure would consist of a concrete chamber, wherein would be located hydraulic and manual controls for a high pressure steel slide gate which would regulate discharge through the outlet pipe. The intake for the outlet pipe would be located about 20 feet above the floor of the tunnel. The outlet con- duit would be placed in the tunnel, and would consist of 60-inch diameter steel pipe, supported by ring girders resting on the floor of the tunnel. The conduit would terminate at a control house located at the downstream portal of the tunnel, wherein releases would be further regulated by a 148-inch diameter needle valve. Access to the outlet pipe and intake structure would be main- tained through the diversion tunnel. For the dam with height of 165 feet, the outlet works would consist of an intake structure similar to those described for the two higher dams, from which water would discharge into a 142-inch diameter steel pipe. The pipe would be supported on ring girders and' would be placed within a reinforced concrete conduit, 8 feet in diameter and horseshoe in section. The conduit would be placed in a trench excavated to sound rock across the right abutment, and would terminate at a control house at the downstream toe of the dam. Re- leases to the outlet pipe would be regulated at the intake structure by a high pressure steel slide gate, operated by controls similar to those for the two higher dams. Further regulation of reservoir releases would be obtained by in- stalling a 36-inch diameter needle valve at the downstream end of the outlet pipe. Access to the pipe and intake structure would be maintained through the outlet conduit. Construction of a dam at the Ferndale site would require the reloca- tion of about 3.5 miles of State Highway 150. The cost of this relocation was estimated by the Ventura County Flood Control District in 1953 to be about $U20,000. Included in the reservoir area is one large ranch, minor agricultural developments, and several small resort and suburban developments. In 1953 the Ventura County Flood Control District also estimated the cost of lands and im- provements up to an elevation of 1,100 feet, which would accomodate a reservoir with storage capacity 12,000 acre-feet, and to an elevation of 1,200 feet, which would be required for storage capacities up to 3U,000 acre-feet. These estimates do not include the cost of acquiring mineral rights in the reservoir area, which rights could substantially increase estimated acquisition costs. From the results of field examination by the Division of Water Resources, it was estimated that depending on the height of dam, from 270 to k$0 acres of trees and brush in the reservoir area would require removal. U-50 Presented in Table 62, are pertinent data with respect to the general features of the three sizes of dam and reservoir considered at the Ferndale site, as designed for cost estimating purposes. For illustrative purposes, a plan, profile, and section for the dam creating a reservoir with storage capacity of 12,000 acre-feet, are shown on Plate 27, entitled "Ferndale Dam on Santa Paula Creek . " TABLE 62 GENERAL FEATURES OF THREE SIZES OF DAM AND RESERVOIR AT THE FERNDALE SITE ON SANTA PAULA CREEK Earthfill Dam Crest elevation, in feet, U.S.G.S. datum Crest length, in feet Crest width, in feet Height, spillway lip above stream bed, in feet Side slopes, upstream and downstream Freeboard, above spillway lip, in feet Elevation of stream bed, in feet, U.S.G.S. datum Volume of fill, in cubic yards Reservoir Surface area at spillway lip, in acres Gross storage capacity at spill- way lip, in acre- feet Type of spillway 1,100 990 30 165 2.5:1 25 910 2,311,1*00 220 12,000 Ogee weir and concrete lined chute Spillway discharge capacity, in second-feet Type of outlet 37,000 h2-inch diameter steel pipe, beneath dam in reinforced concrete conduit 1,150 1,180 1,21*0 1,390 30 30 210 2li0 2.5:1 3:1 30 910 h, 101, 300 310 21*, 000 30 91* 6,33U,800 380 3U,000 Ogee weir and Ogee weir and concrete lined concrete lined chute chute 37,000 37,000 60-inch diameter 60-inch diameter steel pipe, steel pipe, through diversion through diversion tunnel tunnel 1|-51 Presented in Table 63 is a summary comparison of capital and annual costs of the three considered sizes of dam and reservoir at the Ferndale site. Also presented in Table 63 are estimated unit costs of storage capacity and net safe yields of -water that would be developed by construction of the three sizes of reservoir. Yields referred to are those that would result under the uniform release method of reservoir operation. Certain of the relationships presented in Table 63 are depicted graphically on Plates 35, 36, and 37. Detailed esti- mates of cost for the three sizes of dam and reservoir at the Ferndale site are included in Appendix C. TABLE 63 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE FERNDALE SITE ON SANTA PAULA CREEK : Reservoir storage cs ipacity, Item • • in acre-feet : 12,000 : 2U,000 ! 3U,000 Capital Costs Dam and reservoir $5,37l;,000 $7,21*9,000 #9,865, 000 Cost per acre- foot of storage 1*1*8 302 290 Cost per acre-foot of net safe yield 2,150 1,1*80 1,500 Annual Costs Dam and reservoir 277,000 373,000 505,000 Cost per acre-foot of net safe yield 110 76 77 Cost per acre-foot of incremental net safe yield 1*0 78 ii-52 C old Spring Dam and Reservoir . The Cold Spring dam site is located on the upper reaches of Sespe Creek, in Section 6, Township 5> North, Range 22 West, S»B,B. & Ms The site is about three miles downstream from the U, S, Highway 399 bridge across Tale Creek, a tributary of Sespe Creek, Stream bed elevation at the site is about 3*200 feet above an assumed datum of the Santa Clara Water Conservation District which approximates an elevation of 3*190 feet, UtS.G.S. datum. The dam site and most of the reservoir area are located on federally owned land within the Los Padres National Forest. Consideration x^as given to the construction of a dam and reservoir at the Cold Spring site for storage of flood waters in Sespe Creek, and utilization of the waters so con- served in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Sub units of the Santa Clara River Hydrologic Unit. The drainage area of Sespe Creek above the Cold Spring dam site com- prises about 65 square miles, and produced an estimated average seasonal runoff during the base period of about 16,800 acre-feet. It was estimated that xjaste to the ocean of water originating above the dam site would have averaged about 111, 500 acre- feet per season during the base period with the present pattern of land use and water supply development, The Cold Spring dam site was mapped up to an elevation of 3* 550 feet in 1932, by V, M. Freeman for the Santa Clara Water Conservation District, at a scale of one inch equals 100 feet, with contour interval of 10 feet. In 192$, J. B. Lippincott mapped the reservoir area up to an elevation of 3*UlO feet, at a scale of one inch equals 600 feet, with contour interval of 10 feet. Reservoir areas and storage capacities at various stages of water surface eleva- tion, computed from this map, are given in Table 6I4, but the elevations have been adjusted to the datum of the Santa Clara Water Conservation District dam site map by subtracting 10 feet. Above an elevation of 3,UlO feet, the capaci- ties were computed using areas measured from Army Map Service quadrangles, at a scale of 1:31*680, and with a contour interval of 5>0 feet. As previously stated, U.S.G.S. datum is approximately 10 feet lower than District datum, 4-53 TABLE 64 AREAS AND CAPACITIES OF COLD SPRING RESERVOIR Water surface Depth of water : elevation : Water surface : Storage capacity, at dam, in feet : District datum, in feet area, in acres : in acre-feet 3,200 10 3,210 2 10 20 3,220 10 70 30 3,230 22 230 40 3,240 35 515 50 3,250 55 965 60 3,260 70 1,590 70 3,270 95 2,410 80 3,280 125 3,520 90 3,290 160 4,930 100 3,300 200 6,700 110 3,310 230 8,810 120 3,320 260 11,200 130 3,330 290 14,000 140 3,340 350 17,200 150 3,350 410 21,000 160 3,360 480 25,400 170 3,370 550 30,600 178 3,378 610 35,000 180 3,380 620 36,400 190 3,390 690 43,000 200 3,400 760 50,200 210 3,410 840 58,300 220 3,420 920 67,100 230 3,430 990 76,700 240 3,440 1,070 87,000 250 3,450 1,140 98,000 252 3,452 1,160 100,000 260 3,460 1,220 109,800 270 3,470 1,290 122,300 280 3,480 1,350 135,500 290 3,490 1,420 149,400 300 3,500 1,490 164,000 310 3,510 1,560 179,200 4-54 Based upon preliminary geological reconnaissance, the Cold Spring dam site is considered suitable for a properly constructed earthfill, rockfill, or masonry type of dam of low to moderate height. Geology xtfas investigated by the Division of Water Resources in March, 195>2. Two test pits and five core holes, totaling £86 feet in length, were drilled in 19U8 by the Ventura County Flood Control District, and the cores were classified by Dr. T. L. Bailey, Consulting Geologist. Previous geologic studies of the site were made by Dr. Charles P. Berkey, Paul F. Kerr, and Hyde Forbes in the early thirties. The rocks at the Cold Spring site are a gently dipping series of thick-bedded to massive fine-grain sandstones and more thinly bedded silt- stones. A small amount of true shale is also present. The sandstones generally contain a considerable amount of silt, and perhaps some clay. The rocks proba- bly belong to the Cozy Dell formation of Eocene age. The beds on both abutments average nearly east-west in strike, and apparently without exception dip to the north on the flank of an anticline whose axis lies about three-quarters of a mile south of the site. The strike varies locally, largely because of a notable tendency of the beds to thicken or pinch out in short distances. No close folding or contortion of the bed was observed. The northerly dip varies from about 3 to about 20 degrees. The rocks at the dam site are only moderately jointed, and no shearing or faulting was noted. The possible presence of a fault on the right abutment has been reported. More detailed exploration here is desirable if a dam is to be further considered at this site, but it is not believed that any fault on this abutment would be a major problem. There is considerable uncertainty concerning the amount of runoff produced by the Sespe Creek watershed above the Cold Spring site. A U„S.G«S. stream gaging station on Sespe Creek near Wheeler Springs was established in 19U8. This station is located about five miles upstream from the Cold Spring dam site, and measures runoff from about 5>0 square miles of watershed, or about 4-55 20 per cent of that at the U.S.G.S. stream gaging station on Sespe Creek near Fillmore, above which the drainage area comprises about 25U square miles. From 19^8-U9 through 1951-52, there occurred three relatively dry seasons and one wet season© Recorded runoff at the station near Wheeler Springs during the three dry seasons from 19U£-h9 through 1950-51 was about 5.5 per cent of that at the station near Fillmore • However, during the wet season of 1951-52 the runoff at the upper station was about 12 per cent of that at the lower station. It is indicated, therefore, that with an increase in relative wetness of a given season, the percentage of runoff at the upper station increases as com- pared with runoff at the lower station, and that runoff from various portions of the watershed is not proportional to the ratio of respective drainage areas. During the base period, the maximum recorded seasonal flow of Sespe Creek near Fillmore was about 376,000 acre-feet in 19U0-U1, including correc- tions for upstream impairments. It was estimated that during such a wet season the runoff produced by the watershed above the station near Wheeler Springs would be equal to about 20 per cent of that above the station near Fillmore. Thus, it was assumed that for seasons producing runoff in excess of about .376,000 acre-feet at the Fillmore station, runoff at the upper station would be proportional to the ratio of the respective drainage areas. For seasons with lesser amounts of runoff at the lower station, runoff at the upper station was estimated from a curve drawn to show the relationship of runoff of Sespe Creek near Fillmore with that of Sespe Creek near Wheeler Springs during the four seasons of overlapping recordo From this curve, runoff for each of the seasons of the base period without record at the Wheeler Springs stream gaging station was estimated. To derive seasonal runoff at the Cold Spring dam site, estimated or measured seasonal runoff at the Wheeler Springs stream gaging station was increased by 30 per cent, or in proportion to the ratio of the respective drain- age areas. Monthly distribution of seasonal runoff at the Cold Spring dam site 4-56 for each season of the base period was estimated from the measured monthly per- centage of seasonal runoff for Sespe Creek near Fillmore during seasons from 1936-37 through 19U7-U8, and from similar data for Sespe Creek near Wheeler Springs during seasons subsequent to 19U7-U8. Presented in Table 6£ is the estimated monthly runoff of Sespe Creek at the Cold Spring dam site during the base period. 4-57 Q CJ 2 M gd Ph CO ■P Q o in ^1 Q) vO O o 1 a H 0) § n tO £>■ cnCM CM h cn^o en to «t * *\ *\ «\ o en to H -J' O CM CM q q Q o o CM r>- inso o vO en 3 en o en CO vO rH Q O O O O in m CNi O O Q O O o en o cv m -4 H rH o o o o o en cm H H o O O O O en to -4 CM H CM o o o o o m -4 -4 o m vO rH rH o o o o o 4CVHH o o o o o O t«- VN CN cm -4 o o o o o CM m H CO so O cm cm rH o o o o o vO en H H H o o o o o m o o m -4 f>- H o o o o o to H t>- m cm to H en m h rH o o o o o H in en -4- en rH o o o O O !£> t> t>- o O _tf H rH O O O O O -d m o r>- H -4 cm o o cm o o o o o o to -o o to en H o -4 o o o o rl to HC\J o c^- cn cv CM CM O O O O O- I>- CO vO r> -4 to en •» »> to nO CM o o o o cm o o en £> r> -4 o Q en rH o o o o o eno cm tO -4%0 CM o o o o to to in c- -4 t>- c- CM q o o o H\0H\0 r-i H rH Q O O O o o o o o cnvO O in rH c- r>- -4 cm in t>- H CM o o o o o -4 o r> vo r> tO CM O rH O CM en o> o o o o o o o ex) cm in cm en cm mso o CM vO in H o o o o o -J- -4 -4" CM m 00 -4 CO C-- - rH CM H o o o o o O MD O en o H rH H rH vO o o o o o H in o O 00 rH rH i-\ a o w 0) CO r>- co o o e0 en en-? H cm en -4 ITS -4 -4 -4 -4 -4 ■ III i. * i ! vO £> to o O"* s o^ o> rlHHrl o o o o o r-1 r-\ r-\ r-{ r-\ o o o o o O -4 CM CM -4 en rH rH rH rH o o o o o O O 3 33 o o o o o o en mo no CM CM CM o o o o o to -o envo cm CM -4 rH o o o o o O en en in cm tv in rH o o o o o to en CM CM CM o o o o o in en cm rH o t>- to o o -4 -4 -4 -4 in I I I I I mvo r> to o -4-4-4-4-4 o cs o o o H rH H rH rH o in o to o in o in o CM rH in I o in o in I o in o •a o u Si -p ? o a o CO a> CO 5 4-58 Based on the estimates of runoff, monthly studies of operation of Cold ipring Reservoir during the base period were made for four sizes of reservoir of 15,000 acre-foot, 43,000 acre-foot, 77,000 acre-foot, and 100,000 acre-foot storage capacity, under both the uniform release and rapid release methods of operation. In all of the studies, an allowance was made for reduction in effective ^eservoir storage capacity due to sedimentation, in the amount of 3,000 acre-feet. ?his amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 1.70 feet, distributed monthly in accordance with the following tabula- tion, was employed in the operation studies. Net evaporation, 4onth in feet of depth Month October 0.15 April November 0.06 May December 0.04 June January 0.04 July ? ebruary 0.05 August v Iarch 0.10 September TOTAL Net evaporation in feet of depth 0.15 0.19 0.21 0.25 0.25 0.21 1.70 The estimated values of net safe seasonal yield that would be obtained under both the uniform release and rapid release operating criteria, are presented in Table 66. The relationship between reservoir storage capacity and net safe seasonal yield, with Cold Spring Reservoir operated by the uniform release method with releases for maintenance of water levels in Fillmore and Santa Paula Basins is depicted graphically on Plate 36. 4-59 TABLE 66 ESTIMATED NET SAFE SEASONAL YIELDS OF COLD SPRING RESERVOIR (In acre-feet) 35.000 5,000 5,500 5,100 43,000 6,500 7,000 6,600 77,000 10,500 11,800 11,600 100,000 12,000 13,800 12,200 t Uniform release operation t """ Rapid release operation i Available to Oxnard i Available to Oxnard i » Available to Oxnard » Forebay, Oxnard i Forebay, Oxnard t « Forebey , Oxnard Reservoir storage: Plain, end Pleasent • Plain, ond Pleasant i Available within « Plain, end Pleasant capacity « Valley Sucunits, t Valley Subijnits, « Santa Clara River i Valley Subunits i with releases for i without releases i Hydrologic Unit t t maintenance of « for maintenance of i i i around water levels t ground water levels t t 3,500 U,200 6,600 8,800 As a result of the geologic investigation and the reservoir yield stu- dies, estimates of cost were prepared for dams at the Cold Spring site with heights of 178 feet, 190 feet, 230 feet, and 252 feet from stream bed to spillway- lip, creating reservoir storage capacities of 35,000 acre-feet, 43 > 000 acre-feet, 77,000 acre-feet, and 100,000 acre-feet, respectively. For all heights of dam, a rolled fill structure was contemplated, comprised of an impervious core of select earth material, and upstream and downstream sections of random material. Both upstream and downstream slopes of the dam would be 3:1 for the dams of 178- foot, 190- foot, and 230-foot height, and 3.25:1 for the dam of 252 foot height. The impervious sections would have upstream and downstream slopes of 1:1. Crest widths would be 30 feet, comprised of a 10-foot width for the impervious core, and 10-foot widths each for the upstream and downstream random sections. The foregoing selection of random rather than pervious fill for the outer sections of the dam resulted from the absence of suitable permeable material in the area. Employment of the random fill would necessitate the installation of gravel drains in the downstream portion of the dam, to remove any leakage that might occur through the impervious section. A gravel blanket, with a thickness of 6 feet normal to the downstream slope of the impervious fill, would be placed at the contact between the impervious and random fill, 4-60 and would extend to a height of two-thirds of the distance between stream bed and spillway lip. Placing the gravel blanket to this height should amply cover that portion of the face of the impervious fill within the zone of saturation. Seepage intercepted by the blankets would be distributed into four longitudinal gravel drains extending to the toe of the random fill. These drains would be about 6 feet in thickness and 15 feet in width, and would be placed along each abutment and at the one-third points across the stream bed. The upstream face of the dam would be protected against wave action by rock riprap placed to a depth of 3 feet normal to the slope, The downstream face of the dam would be stabilized and protected against the erosive action of rainfall by finishing off with top soil, rolling in barlejr straw, and planting bacharis shoots. Horizontal gutters, paved with cobbles, would be provided at 30-foot vertical intervals. In the cost estimates, it was assumed that a depth of about 18 feet of sand and gravel would be stripped in the channel under the impervious core. On the left abutment, depths of 7 feet of rocky talus material, plus an addition- al 5 feet of bedrock, would be stripped for a vertical distance of about 100 feet above stream bed. Above this elevation the abutment consists of massive sand- stone and thinner bedded siltstone outcrops, of which a depth of 5 feet would be stripped under the impervious core. Under the impervious section of the right abutment, depths of about 2 feet of soil and weathered rock, plus 5 feet of under- lying jointed bedrock, would be stripped. For the random fill sections, a nominal depth of stripping of 2 feet was assumed throughout the contact area. It was assumed that foundation treatment would include moderate grouting. Earthfill material considered suitable for the impervious section of the dam occurs in limited quantities in terraces both upstream and downstream from the site, but would probably require some sorting. By utilizing Rose Valley, about two miles from the dam site, as a borrow source for fill, it was estimated that sufficient material would be available for dams up to 272 feet in height. 4-61 Two samples of material, taken from possible borrow areas, were tested by the Division of Water Resources and were deemed adequate for use in the impervious section. Borrow material suitable for the random sections is available in some- what limited quantities from stream gravels and from the coarse fraction in the aforementioned terrace deposits. It was estimated that a portion of the material stripped beneath the impervious section would be used in the random sections. The sandstones of the area would be quarried for riprap. It was assumed that compac- tion of fill material in both the impervious and random sections of the dam would be effected by either sheepsfoot tampers or pneumatic rollers. Gravel for the drains and pervious blanket would probably have to be imported from Cuyama Valley, where Tinta and Castle Creeks enter into the Cuyama River, about 24 miles distant. Spillways, for all heights of dams considered, would have a discharge capacity of 50,000 second-feet, which is the estimated peak discharge of a once in 1000-year flood. The spillways were designed as concrete lined overpour chutes with ogee-weir control sections. For the dam of 178 foot height, the maximum depth of water above the spillway lip would be 17 feet, 5-foot residual freeboard. For the three larger dams, the maximum depth of water above the spillway lip would be 15 feet, with an additional 5 feet of residual freeboard. The spillway weirs and channels would be excavated across the nose of the left abutment, and would discharge into a small ravine downstream from the toe of the dam. As it was estimated that the dams of 178 and 190 foot height, could be constructed in one year, it was assumed that diversion of waters in Sespe Creek would be effected through the outlet conduit. For the dams of 230 and 252 foot height, requiring an estimated two years fcr construction, it was assumed that a 16-foot diameter concrete lined tunnel of horseshoe section would be constructed through the left abutment to provide for diversion of winter flows. The tunnel would be about 1,520 feet in length for both dams. 4-62 It was assumed that outlet works for both of the larger dams would utilize the diversion tunnel after construction. The approach channel for the outlet works would be 90 feet in length, with a varying bottom width and 1:1 side slopes. Maximum depth of cut would be about 40 feet. A submerged concrete intake structure would be located immediately upstream from the tunnel portal. This structure would consist of a concrete chamber, wherein would be located hydraulic and manual controls for a high pressure slide gate which would regulate discharge through the outlet pipe. The intake for the outlet pipe would be located about 25 feet above the floor of the tunnel. The outlet conduit would be placed in the tunnel, and would consist of 60-inch diameter steel pipe, supported by ring girders resting on the floor of the tunnel. The conduit would terminate at a control house located at the downstream portal of the tunnel, wherein releases would be regulated by a 54-inch diameter Howell-Bunger valve. Access to the pipe and intake structure would be maintained through the diversion tunnel. For the dams with heights of 178 and 190 feet, the outlet works would consist of an intake structure similar to those described for the two higher dams, from which water would discharge into a 54-inch diameter steel pipe. The pipe would be supported on ring girders and would be placed within a reinforced con- crete conduit, 9.5 feet in diameter and horseshoe in section. The conduit would be placed in a trench excavated to sound rock across the left abutment, and would terminate at a control house at the downstream toe of the dam. Releases to the outlet pipe would be regulated at the intake structure by a high pressure steel slide gate, operated by controls similar to those for the two higher dams. Further regulation of reservoir release would be obtained by installing a 48-inch diameter Howell-Bunger valve at the downstream end of the outlet pipe. Access to the pipe and intake structure would be maintained through the outlet conduit. The Cold Spring dam and reservoir area is owned by the United States 4-63 Government, except for one privately owned ranch containing about 44 acres. This ranch lies primarily along the bed of Sespe Creek, and is moderately rolling and undulating land, containing a small orchard, six modest frame buildings, and an outbuilding of the cabin type. The Ventura County Flood Control District, in January, 1952, estimated the cost of acquisition of the privately owned land and improvements to be $25,000. This amount does not include the cost of acquiring mineral rights in the reservoir area. The property has been leased for oil speculation, but the nearest drilling activity is a wildcat well several miles distant. Construction of the three larger dams at the Cold Spring site would require the relocation of about 27,000 lineal feet of U. S. Highway 399, and of two bridges, one crossing Tule Creek and the other Sespe Creek. No road reloca- tion would be required for construction of the smallest of the four dams. An estimate of cost of relocating U.S. Highway 399 was made by the California Division of Highways in 1953. It was assumed that construction of an all purpose access road, approximately two miles in length, would be required for construction of all heights of dam. From the results of field examination of the reservoir area, it was estimated that, depending on the height of dam to be constructed, from 760 to 1,290 acres of minor clearing in the reservoir area would be required. Presented in Table 67 are pertinent data with respect to the general features of the four sizes of dams and reservoirs considered at the Cold Spring site, as designed for cost estimating purposes. For illustrative purposes, a plan. profile, and section for the dam creating a reservoir with storage capacity of ■ 35,000 acre-feet are shown on Plate 28 entitled "Cold Spring Dam on Sespe Creek". 4-64 TABLE 67 GENERAL FEATURES OF FOUR SIZES OF DAM AND RESERVOIR AT THE COLD SPRING SITE ON SLSPE CREEK iarthf ill Dam Crest elevation, in feet, Santa Clara Water Conservation District datum . . . 3,UOO Crest length, in feet 730 Crest width, in feet 30 Height, spillway lip above stream bed, in feet 178 Side slopes, upstream and downstream ... 3 si Freeboard, above spillway lip, in feet 22 Elevation of stream bed, in feet, Santa Clara Water Conser- vation District datum 3,200 Volume of fill, in cubic yards 1,919,600 Reservoir Surface area at spillway lip, in acres Gross storage capa- city at spillway lip, in acre-feet .... Type of spillway. . . Spillway discharge capacity, in second- feet Type of outlet. . . . 606 35,000 Ogee weir and concrete lined chute 3,lao 3A50 3,1*72 770 860 920 30 30 30 190 230 252 3:1 3:1 3.25:1 20 20 3,200 3,200 2,2U6,500 3,1+03,000 690 1+3,000 Ogee weir and concrete lined chute 50,000 50,000 514-inch dia- 51|-inch dia- meter steel meter steel pipe beneath pipe beneath dam dam 99$ 77,000 Ogee weir and concrete lined chute 50,000 60-inch dia- meter steel pipe through diversion tunnel 20 3,200 lt,569,100 1,156 100,000 Ogee weir and concrete lined chute 50,000 60-inch dia- meter steel pipe through diversion tunnel k-6$ Presented in Table 68 is a summary comparison of capital and annual costs of the four considered sizes of dams and reservoirs at the Cold Spring site. Also presented in Table 68 are estimated unit costs of storage capacity and net safe yield of water that would be developed by construction of the four sizes of reservoir. Yields referred to are those that would result under the uniform release method of reservoir operation with releases for maintenance of historic ground water levels. Certain of the relationships presented in Table 68 are depicted graphically on Plates 35, 36 and 37. Detailed estimates of cost for the four sizes of dam and reservoir at the Cold Spring site are included in Appendix C. TABLE 68 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE COLD SPRING SITE ON SESPE CREEK Item Reservoir storage capacity in acre-feet 35.000 43,000 77.000 100.000 Capital Costs Dam and reservoir $3,796,000 $5,613,000 $7,283,000 $8,571,000 Cost per acre-foot of storage 108 131 95 86 Cost per acre-foot of net safe yield 760 860 690 710 Annual Costs Dam and reservoir 199,000 292,000 378,000 446,000 Cost per acre-foot of net safe yield 40 45 36 37 Cost per acre-foot of incremental net safe yield 62 22 45 4-66 Topatopa Dam and Reservoir . The Topatopa darn site is located on Sespe Creek about 19 miles below the Cold Spring dain site, and is in Section 36, Township 6 North, Range 20 West, S.B.b. & M. Stream bed elevation at the site is about 2,100 feet, U.S.G.S. datum. Consideration was given to the construction of a dam and reservoir at the Topatopa site for storage of flood waters in Sespe Creek, and utilization of the waters so conserved in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. The drainage area of Sespe Creek above the Topatopa dam site comprises about 171 square miles, and produced an estimated average seasonal runoff during the base period of about li3>600 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 37*600 acre-feet per season during the base period with the present pattern of land use and water supply development. The Topatopa dam site and reservoir area were surveyed in 1950 hy Fairchild Aerial Surveys, Inc., using photogrammetric methods, for the Ventura County Flood Control District, Zone 2. The dam site was mapped up to an eleva- tion of 2,750 feet at a scale of one inch equals 100 feet, with a 5-foot contour interval. The reservoir area was mapped up to an elevation of 2,650 feet, at a scale of one inch equals iiOO feet, with a contour interval of 20 feet. Storage capacities of Topatopa Reservoir at various stages of water surface elevation are given in Table 69. U-67 TABLE 69 • AREAS AND CAPACITIES OF TOPATGPA RESERVOIR • • Water surface Depth of water : elevation : Water surface : Storage capacity, at dam, in feet : U.S.G.S. da torn, : area, in acres : in acre-feet : in feet 2,100 20 2,120 5 50 Uo 2, mo 17 270 60 2,160 35 780 60 2,180 61 1,7U0 100 2,200 90 3,250 120 2,220 120 5,310 lUo 2,2UO 150 7,950 160 2,260 180 11,200 180 2,280 220 15,200 200 2,300 270 20,000 220 2,320 320 25,900 2U0 2,3U0 370 32,900 260 2,360 U30 U0,900 280 2,380 510 50,300 300 2,U00 580 61,200 320 2,U20 650 73,500 322 2,U22 660 75,000 3U0 2, UUO 730 87,300 355 2,U55 790 100,000 360 2,U60 810 102,600 380 2,U80 900 119,700 Uoo 2,500 1,020 138,900 U20 2,520 1,110 160,300 UUo 2,5UO 1,230 183,800 U60 2,560 1,350 209,600 U80 2,580 1,U80 238,000 500 2,600 1,590 268,700 520 2,620 1,720 301,800 5Uo 2,6U0 1,850 337,500 55o 2,650 1,920 356,300 U-68 Geologic investigation indicates that the Topatopa dam site is suit- ible for almost any type of structure up to heights above stream bed of the >rder of lj.00 feet. The geology of the site was studied by the Division of Water tesources during the current investigation. Previous geologic studies had been lade by Dr. Charles P. Berkey, Paul F, Kerr, and Hyde Forbes, and by geologists :f the Division of Water Resources in connection with the preparation of Division of Water Resources Bulletin No. 1±6. Some geologic work at the site has also been ione by Thomas L. Bailey, Consulting Geologist. Three core holes were drilled jat the Topatopa dam site in I9I48 by the Ventura County Flood Control District totaling 302 feet in length. In 1952, 17 core holes were drilled by the United Water Conservation District, with a total length of lj>lf71 feet. Rock exposed at the Topatopa dam site consists of hard, greenish-grey sandstone, interbedded with subordinate amounts of hard black or sandy shale. The sandstone beds vary from very massive to moderately thin bedded. The sand- stone generally takes on a mottled appearance on weathering, and ripple-marked beds are present on both abutments just above the channel section. Strike of the bedding is across the channel and is quite consistent, averaging about north 30 degrees east. The dip is also uniform and averages about 18 degrees in a south- east direction, or downstream. No positive evidence of a fault down the channel at the axis of the Topatopa dam h&s been found. However, a calcite deposit found in one of the drill holes of the United Water Conservation District suggest that a fault may exist in the channel at the point of drill hole No. 13. * A fault was reported by Berkey and Kerr on the left abutment between about 0.25 and 0.5 mile upstream from the axis in a ravine containing a dry weather spring. The dip of the beds on either side of this fault varies from 30 degrees north on one side to 50 degrees south on the other, with gouge and calcite veins present between. This fault is now believed to extend along the left abutment downstream at an eleva- tion of about 750 feet above the stream bed. It appears that the fault finally U-69 approaches the stream bed and crosses it immediately above the confluence of Sespe and Alder Creeks. Two minor faults were noted on the left abutment, one of which dips steeply upstream and shows a displacement of about 20 feet, and the other which appears to be a small thrust. Another minor fault was noted in the right abutment. Three sets of joints occur at the axis of the dam, and probably persist through the area of the site. The right abutment of the Topatopa dam site has very steep rugged walls for the first 200 feet above the stream bed, and then slightly gentler slope with a blocky uneven surface. The rock is strongly jointed, with joints somewhat open near the surface. As a result of the drilling program of the United Water Conservation District, it was determined that sound rock in the channel section lies beneath about UO feet of sand, silt, gravel, and boulders of sandstone and crystalline rock. The first 15>0 feet above stream bed on the left abutment consists of a nearly vertical cliff, with a talus deposit to an elevation about 50 feet above the base of the cliff at the dam axis. Above the cliff the slope of the abutment is slightly gentler. The entire abutment is strongly jointed, including some closely spaced sets. Borrow pit exploration for impervious material for a possible earth filled dam at the Topatopa site was conducted by the Division of Water Resources in 1951 > using a bulldozer to expose an area located about one mile upstream from the site. Tests of nine samples from this area showed the material to be suitable for the impervious section of an earth filled dam. The United Water Conservation District explor- ed the same area in 1952, and another area at a closer location to the dam site, by drilling auger holes. Drilling indicated that approximately 6,700,000 cubic yards of impervious material were available within one mile upstream from the site. Pervious material for a fill-type dam was determined to be quite limited. U-70 Records of runoff at the Topatopa dam site are not available, lowever, estimates of runoff were made for the base period, utilizing the short •ecord at the U.S.G.S. stream gaging station on Sespe Creek near Wheeler Springs, md the longer record at the U.S.G.S. station on Sespe Creek near Fillmore. Due bo the generally easterly course of Sespe Creek above the dam site, it was assumed that the runoff characteristics would be similar to those at the simi- larly situated Cold Spring dam site. For this reason, the method of estimating runoff described for Cold Spring Reservoir was employed for the Topatopa site. To derive seasonal runoff at Topatopa Dam, estimated or measured seasonal runoff at the Wheeler Springs stream gaging station was increased by 2li2 per cent, or in proportion to the ratio of the respective drainage areas. Table 70 presents !the estimated monthly runoff of Sespe Creek at the Topatopa dam site during the base period. lt-71 p o O O O Q to o o o o o o co ^2 o o o o o to ^o c*- o o o vo cm cm o *\ *s »\ «\ •■» C>- CO -4 in CV in r>- in r-\ CM Q O O O O O O CM m CN2 •V «s ». » ». vO(>HH(M o o en vO 3 t CD CO o vO o o o in in in CM vO vO O O O O O t> tO so H to CM CV en 8 o o o o o p d) 0) » (1) f-l o 2 1 ID I P. Sh ft, Q O Q O 4(^Oia m c-- H o o o q o o o ^o -4 en vO H Cn -4 rH rH o o o o o O m cneM H o o o o o cm cm on in >A(MH o o o o o -4 en -4 cn^o so rH in r>- h o o o o o o to en en cm r-\ o r-T cm o o o o C>- ITNsO Cn HONH H cv o o o o o r- o vo en n o r> CM H CM H o 3 o O o o £: ° S o- C*- cm CO in o o o o o" £> c- m en cm O O vO CO cc\ #\ Ik »t »V #\ mrH cn^n rH o o o o o o o h cm o ->o en en en en en 1 22,740 68,560 2,280 930 o o o o o in m cm m cm H I s - in r>- m •V *S #\ «\ in en mm to CM CM o o q o o mo o to o- ud -4 cm -3- en -4 o o CM o o o o q cm co O O nO •* ^ *\ 9\ t>- in rH CN2 cm en o o o o o en en H into -4- r>- Oso o *\ 9% 9\ 9\ tO vO -4 -4 nO rid o o o o o in o en mso o rH in d, in o rH 43 o o q o O H rH c- o H c*- in •V «h •* -* H rH o o o o o cm -3- cm r>- o o rH in to en #* «i #\ #\ CM H in H CM CM o o o o o en o to c- h O- H H en H o CM i 1 -p o en J) cP H o o o o en cm -4 to -4 O O H •» •» *» OOJH O O O O O to CM -4MD O OOtnH4 CM cm en H o o o o o HvOiX) -tH -4 O rH en -4- en o in o o o o O H OnO CM -4 CNi H o o o o o rH vO -4 CM -3" cm en >n o o o o o HrHAvOvO CM -tf o CM «H o CM ■P o o c o CO 03 CD CO q o o o OHOtO en enev h t>co o o en en en -d - i i i i \o r>- co o o o o o H H H rH o o o o o O O CO vO H CM enH CM CM rH cm en -* in -4- -4 -4- -J" -* I I I I I OHNc^i4 -4 -4 -4 -4 -4 o o o o o H rH rH H r^ O O O O O en co >n en cm vQ J> tO O O -4 -4 -4 -4 m » 1 • I • UAsO l"- CO O -4 -4- -4 -4 -t On O O O o H rH rH rH rH in I o in o c o CO ed O m CD W) rti § U-72 Based on the estimates of runoff, monthly studies of operation of Topatopa Reservoir during the base period were made for three sizes of reservoir, I of 50,000 acre-foot, 75,000 acre-foot, and 100,000 acre-foot storage capacity, under both the uniform release and rapid release methods of operation. In all of the studies, an allowance was made for reduction in effective reservoir storage capacity due to sedimentation, in the amount of 8,000 acre-feet. This amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 1.70 feet, distributed monthly in accordance with the following tabulation, was employed in the operation studies. Net evaporation, Net evaporation, Month in feet of depth Month in feet of depth October 0.15 April 0.15 November 0.06 May 0.19 December 0.04 June 0.21 January 0.04 July 0.25 February 0.05 August 0.25 March 0.10 September 0.21 TOTAL 1.70 The estimated values of net safe seasonal yield that would be obtained under both the uniform release and rapid release operating criteria are presented in Table 71. The relationship between reservoir storage capacity and net safe seasonal yield, with Topatopa Reservoir operated by the uniform release method with releases for maintenance of water levels in Fillmore and Santa Paula Basins, is depicted graphically on Plate 36. table 71 estimated net safe seasonal yields of topatopa reservoir (In acre-feet) : Uniform release operation Rapid release operation : Available to OxnaFJ Avai lable to Oxnard : Forebay, Oxnard Forebay, Oxnard Avai lable to Oxnard Reservoir storage: Plain, and Pleasant Plain, and Pleasant Available within Forebay, Oxnard capacity : Valley Submits* Valley Subunits, Santa Clara River Plain, and Pleasant * with releases without releases Hydrologic Unit Valley Subunits : For maintenance of for maintenance of : ground water levels ground water levels 1 50,000 75,000 100,000 8,000 12,U00 16,500 8,l400 12,900 17,000 8,100 12,500 16,700 6,000 9,000 12,000 4-73 As a result of the geologic investigation, yield studies, and reconnai- ssance type estimates of cost of dams of various heights and types, it was con- cluded that the most economical type of dani at the Topatopa site would be con- crete arch, with a maximum physical limit in height of about iiOO feet above stream bed. To determine the variation in cost with height of dam, and the accom- plishments of reservoirs created by various heights of dam, estimates of cost were prepared for concrete arch dams 280 feet, 322 feet, and 355 feet in height from streambed to top of spillway gates, creating reservoirs with storage capa- cities of 50*000 acre-feet, 75*000 acre-feet, and 100,000 acre feet, respectively. The dams would be concrete arches, of the variable radius and variable angle type, and would be located so as to best fit the topography at the site. In the cost estimates, it was assumed that a depth of about kO feet of sand, gravel, and boulders would be stripped in the channel section. On the right abutment, it was assumed that a depth of about 25 feet of jointed rock would be stripped for the first 200 feet above the streambed, and that above this elevation the depth of stripping would be about 35 feet. It was assumed that on the left abutment, a depth of about 18 feet of rock would be stripped for the lowermost 200 feet in elevation above stream bed, and that above this elevation the stripp- ing depth would be about 35 feet. Water testing of several of the core holes drilled by United Water Conservation District indicated that moderate to heavy grouting of the foundation would be necessary. For cost estimating purposes, it was assumed that a concrete batch plant would be placed in the vicinity of the d?m site during construction. Concrete aggregates could be made locally from a granite deposit located about three miles upstream. Spillways, for all heights of dam considered, would have a discharge capacity of 82,000 second-feet, which is the estimated peak discharge of a once in 1,000-year flood. For each of the three sizes of dam, two spillways were incor- porated in the design. A primary spillway would be provided along the extreme U-7U right end of the dam. together with a secondary spillway formed by a notch in the center of the dam. The primary spillway would be equipped with three tainter gates, each 30 feet in length and 20 feet in height. With the water level in the reservoir at the lip of the notched spillway and at the top of the gates, the gated spillway was designed to discharge 28,000 second-feet. With an additional depth of water of 10 feet, the gated spillway would discharge 52,000 second-feet, and the notched spillway 30,000 second-feet. A residual freeboard of 5 feet was provided above this maximum water surface elevation. No provision was made for cushioning of the stream bed, below the notched spillway, as such spill would be very infrequent. The primary spillway would consist of an ogee weir, with the aforementioned gates, and a concrete lined chute discharging into Sespe Creek about hOO feet downstream from the dam. The design of the primary spillway included a concrete gravity thrust block on its left side, separating the spillway weir from the arch. This thrust block would also act as the left training wall for spillway discharge. Outlet works would include a 60-inch diameter steel pipe, placed through the dam near the right abutment at an elevation of 2160 feet. Discharge from the reservoir would be controlled by a high pressure slide gate, h-S feet by k'5 feet in dimensions, on the upstream face of the dam. Releases would also be controlled at the downstream end of the outlet pipe by a 5h-inch diameter Howell-Bunger valve. A trash rack structure would be placed at the upstream end of the outlet pipe. It was estimated that construction of the dam of 280 foot height would require about two years, that of 322 foot height, two and one-half years, and the dam of 355 foot height, about three years. Diversion of the stream during construction would be accomplished by means of a flume or pipe, with the aid of a small coffer dam. Winter flood flows could be passed over a depressed section of the concrete dam. U-75 It was estimated that between 510 and 790 acres of minor clearing would be required in the reservoir area, depending on the height of dam to be constructed. The Topatopa dam site and most of the reservoir lands are federally owned, and in the Los Padres National Forest. In 1952, the cost of acquisition of private lands in the reservoir area was estimated by the Ventura County Flood Control District to be about $25,000 for the two smaller dams, and about $62,500 for the larger dam. An all weather access road approximately 10.5 miles in length would be required before construction could start. The United Water Conservation District estimated in 1952 that this road would cost about $1400,000. Presented in Table 72 are pertinent data with respect to the general features of the three sizes of dams and reservoirs considered at the Topatopa site, as designed for cost estimating purposes. For illustrative purposes, a plan, profile, and section for the dam creating a reservoir with storage capacity of 100,000 acre-feet are shown on Plate 29, entitled "Topatopa Dam on Sespe Creek. " k-16 TABLE 72 GENERAL FEATURES OF THREE SIZES OF DM1 AND RESERVOIR AT THE TOPATOPA SITE ON SESPE CREEK Concrete Arch Dam Crest elevation, in feet, U.S.G.S. datura 2,395 2,1*37 Crest length, in feet . . 850 965 Crest width, in feet. . . 9 10 Height of dam, to top of spillway gates above stream bed, in feet 280 322 Freeboard, above top of spillway gates, in feet 15 15 Elevation of stream bed, in feet, U.S.G.S. datum 2,100 2,100 Volume of concrete in dam, in cubic yards. . . 287,000 1*12,000 Reservoir Surface area at top of spillway gates, in acres 510 656 Gross storage capacity, at top of spillway gates, in acre-feet. . . 50,000 75,000 Type of spillways .... Notched overpour, Notched overpour, and ogee weir and ogee weir with gates ard with gates and concrete lined concrete lined chute chute Spillway discharge capacity, in second- feet 82,000 82,000 Type of outlet 60-inch dia- 60-inch dia- meter steel meter steel pipe, through pipe* through dam dam 2,U70 1,120 10 355 15 2,100 522,000 788 100,000 Notched overpour, and ogee weir with gates and concrete lined chute 82,000 60-inch dia- meter steel pipe, through dam It- 77 Presented in Table 73 is a summary comparison of capital and annual costs of the three considered sizes of dam and reservoir at the Topatopa site. Also presented in Table 73 are estimated unit costs of storage capacity and net safe yields of water that would be developed by construction of the three sizes of reservoir. Yields referred to are those that would result vnder the uniform release method of reservoir operation. Certain of the relationships presented in Table 73 are depicted graphically on Plates 35, 36, and 37. Detailed estimates of cost for the three sizes of dam and reservoir at the Topatopa site are included in Appendix C. TABLE 73 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE TOPATOPA SITE ON SESPE CREEK : Reservoir storage capacity, Item in acre-feet : 50,000 : 75,000 : 100,000 Capital Costs Dam and reservoir 9 9,155,000 $ 12,520,000 $ i5,5Uo,ooo Cost per acre-foot of storage 183 167 155 Cost per acre-foot of net safe yield 1,11*0 1,010 9h0 Annual Costs Dam and reservoir 1*82,000 652,000 805,000 Cost per acre-foot of net safe yield 60 53 h9 Cost per acre-foot of incremental , net safe yield 39 * 37 U-78 Hammel Dam and Reservoir , The Hammel dam site is located on the lower reaches of Sespe Creek, in Section 2, Township h North^ Range 20 West, S.B.B. & M e The site is about four miles north and one mile west of the town of Fillmore, and about seven miles upstream from the confluence of Sespe Creek with the Santa Clara River. Stream bed elevation at the site is about 790 feet, UoS.G.S, datum* Consideration was given to the construction of a dam and reser- voir at the Hammel site for storage of flood waters in Sespe Creek, and utiliza- tion of the waters so conserved in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunitsof the Santa Clara River Hydrologic Unit, The drainage area of Sespe Creek above the Hammel dam site comprises about 2l\6 square miles, and produced an estimated average seasonal runoff during the base period of about 92,000 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 73,600 acre-feet per season during the base period with the present pattern of land use and water supply development The Hammel dam site and reservoir area were surveyed in 1950 by Fairchild Aerial Surveys, Inc. using aerial photogrammetric methods, for the Ventura County Flood Control District, Zone 2o The dam site was mapped up to an elevation of 1,325 feet, at a scale of one inch equals 100 feet, with a 5-foot contour interval. The reservoir area was mapped at a scale of one inch equals UOO feet, with a contour interval of 20 feet. Storage capacities of Hammel Reservoir at various stages of water surface elevation are given in Table 7U. U-79 TABLE lh AREAS AND CAPACITIES OF HAMMEL RESERVOIR Water surface Depth of water : elevation : Water surface ; Storage capacity, at dam, in feet : U.S.G.S. datum, in feet area, in acres : in acre-feet 790 60 850 6 180 70 860 11 270 80 870 17 405 90 880 22 600 100 890 27 845 110 900 32 1,140 120 910 38 1,490 130 920 45 1,910 140 930 51 2,390 150 940 58 2,930 160 950 64 3,540 170 960 71 4,210 180 970 77 U,960 190 980 84 S,770 200 990 91 6,640 210 1,000 98 7,590 220 1,010 110 8,610 230 1,020 115 9,700 240 1,030 120 10,900 250 1,040 130 12,100 260 1,050 140 13,400 270 1,060 145 14,800 280 1,070 155 16,300 290 1,080 160 17,900 300 1,090 170 19,600 310 1,100 180 21,400 320 1,110 190 23,300 330 1,120 200 25,000 340 1,130 210 27,300 350 1,140 220 29,400 360 1,150 230 31,700 370 1,160 240 34,000 380 1,170 250 36,500 390 1,180 260 39,000 400 1,190 270 41,700 410 1,200 285 44,500 420 1,210 300 47,400 428 1,218 308 50,000 430 1,220 310 50,400 440 1,230 325 53,600 450 1,240 340 56,900 460 1,250 350 60,400 470 1,260 365 63,900 480 1,270 380 67,700 490 1,280 390 71,500 500 1,290 410 75,500 510 1,300 420 79,700 rao"" Based upon preliminary geological reconnaissance, the Hammel dam site appears suitable for a moderately high masonry structure. No prior geologic work at this site is known, nor has it been drilled. The dam site is located on the southerly limb of the Coldwater anticline, a distinct structural feature in both Coldwater and Sespe formations. The underlying Coldwater sand- stone is exposed upstream from the dam site along the anticline, while the Sespe formation is the only rock exposed in the vicinity of the axis. The beds dip steeply downstream about 60 degrees south, and strike across the channel about | north 65 degrees east. The Sespe formation at the Hammel site is a medium to coarse grained, reddish brown, bedded sandstone, generally well indurated. Bedding planes and color banding in the various beds are noteworthy. There are relatively few joints and fractures, but one discontinuous open fracture parallels the left abutment in its lower third near the channel section at the axis. No serious structural defects were noted in this area. The harder beds of sandstone form- ing the abutments are several hundreds of feet in stratigraphic thickness, and have formed a narrow "V"-shaped canyon with slopes averaging steeper than 1:1 in the lower 300 feet of the cross section at the dam site. The right abutment in the lower portion, to an elevation about 50 feet above stream bed, has talus blocks up to 50 feet in diameter. Average depth of talus in this area is 20 feet. Above the talus, the right abutment has a light cover of soil and talus over moderately jointed rock. In the channel section, about 120 feet in width, there is a filling of gravels, boulders, and blocks up to 30 feet in diameter. No signs of faulting or pronounced shears were noted in the channel section. A nearly vertical bare cliff rises about 250 feet above stream bed on the left abutment, with good quality rock exposed. Above the top of this cliff the exposed rock exhibits more pronounced jointing. The left abutment appears more favorable topographically for appurtenant features such as outlet tunnels. The canyon is narrow and appurtenant structures may 4-81 be in a hazardous position due to the possibility of large blocks sliding into the canyon. Records of runoff at the Haramel dam site are not available* However, runoff at the site was estimated equal to 97 per cent of the measured runoff at the U.S.G.Si stream gaging station on Sespe Creek near Fillmore, adjusted for diversions made upstream from the gaging station by the Fillmore Irrigation Company. The estimates were based on the ratio of watershed areas above the dam site and gaging station, weighted by estimated mean precipitation on the respective areas. The estimated monthly runoff of Sespe Creek at the Hamrael dam site during the base period is presented in Table 75. 4-82 Q O H P Oh W CO i o S3 M Eh M co 1 Oh B CO Cm Cm s 1 fH -p 0) Q) «H I O o o o o CV ua O H O o- t>- UA *\ *\ *\ *s IAH4H O CO -J" (TV H cv O O O O vO CV -J-nO u\C\JO(M o o o o UAvO CV to CO H O O O O -4- C*- O -4 H CV UA CO H CV O O O O rH CV CO UA vO CO HsO •\ *4 *\ CV COiH O O O O -4 H 0-4 o o o o o CO £> tXl -4 CV co o coco o- •\ #\ #\ «\ #\ -4; O ua CO CV CO r-\ r-\ O O O O O O H O O O C*- -j-^O £>- co o o o o o 040COO n4C0O ^A •\ •> CV H o o o o o lAcAO -4-CO C*~ vO CV CO vO o o o o o rH C- -4 CV O iaoco to r°\ •x n *\ *\ *\ cv co t^- co o sO -4 H 3 co O UA O H o o o o o CV sO vO -4 o CO CV H H H O O H CO rH H O O O O O CV C^-nO vO o •V 9\ «\ »\ * \OHCMr\H Q O O O O O CV O -4" O CO O O PA CO UA c- H H CO COO CV O O O O O CO O O- O -40 O •» #t ■* *\ *0 CO CO CO rH r— I O O O O COO r-\ CV CO CO CO O •v *\ •> «\ o to O to ua cv H H o o o o -4 CO O-O ua CO O -4 •\ «\ •% «\ Hv044 vO O r-\ o o o o CO O CO o CO rH IN- O O CV £> CO O O O O O -4" OsO ua O H CO O O -4" «\ «\ «\ «\ ** IAO4041A O H O O O O O C-iAOO «NH vO ua CO O -4 •V »\ «\ w\ «% O CO cv o o CV UA UA H i-4 O O O O Q to uaO H -4 O -4 O CO O «\ *\ «\ •* *\ O CO 0-0 o O CO CO CV o o o o o OHCMH£> 44t0 C^-O •v «\ #\ «\ *\ CV uaO -4 H CO >-0 o o o o o CO CO CO O vO CO CV H H H o o o o o O H H O- O UA CO CV H CV o o o o o coo CO H CO H UA -4 COCO O O O O O CO UAkO O £> o o o l> c- CO o o o o o UA CO CV CO UA OvOtX) cm r> •* ^ •» «^ ^ -4 rH H H rH rH O O O O O if \ O CO CO CV CO CV O O O CO CV H H COH O O Q O O UA'O O CV to O O- CO £> c^- CV CV lO o o o o o O CO H H CO CO -4 to {>- CV (.V U> CO o o o o CV CO CV CO cv ts CO o «\ •% «\ *^ ~4 CO CO rH O O O O CO^O CV I>- O C~- COCO o o o o O- CO H O- tO mcMO •> »> cv H o o o o o o o o o o co ^o CO -4 -4- O OsO CV c^ rH UA C^ O O rH O -4 *0 t> •s »v *\ «v •\ 9\ 9\ t>- o t>- CV C-CO H rH H H o o o o o CO -4sO CV CO CO O ua CO -4 O O O O O O H CV ua O COCO ~4vO CO o o o o o O O ON CO r^ o cv cv 3 o o o o o CO ON O o o -4 CO CV CV H a o to ct3 0) CO C^- CO ON o CO CO CO -4 1 1 1 1 vO C- CO o CO CO CO CO Qs O O O r^ r-\ r-\ <-^ CO -4 to -4-4-4 • I L CV co -4 H -4 1 -4- ^f— 4 ^t" -^ O O 0^ O ON rH rH H rH H vO O- CO o O -4 -4 -4" -4- ua I I I I I UAsO f- CO ON -4 -4 -4 -4 -4 ON ON ON O ON <-\ H <-\ r-\ r-^ o CO o o o UA o CV CO o o UA o H C- O 3 o vO CO o UA CV 5 CV o ON UA I o UA ON UA I o UA O H ft O ■p CO CO o H O H 0} O CO cd CO CO CO w c6 U 4 fc-83 Based on the estimates of runoff, monthly studies of operation of Hamrnel Reservoir during the base period were made for two sizes of reservoir, of 25,000 acre-foot and 50,000 acre-foot storage capacity, under both the uni- form release and rapid release methods of operation. In all of the studies, an allowance was made for reduction in effective reservoir storage capacity due to sedimentation, in the amount of 12,000 acre-feet. This amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 1.70 feet, distributed monthly in accordance with the following tabulation, was employed in the operation studies. Net evaporation, Net evaporation, Month in feet of depth Month in feet of depth October 0.15 April 0.15 November 0.06 May 0.19 December 0.04 June 0.21 January 0.04 July 0.25 February 0.05 August 0.25 March 0.10 September 0.21 TOTAL 1.70 The estimated values of net safe seasonal yield that would be obtained under both the uniform release and rapid release operating criteria are presentee in Table 76. The relationship between reservoir storage capacity and net safe seasonal yield, with Hammel Reservoir operated by the uniform release method, with releases for maintenance of ground water levels in Fillmore and Santa Paula Basins, is depicted graphically on Plate 36. 4-84 TABLE 76 ESTIMATED NET SAFE SEASONAL YIELDS OF HAMMEL RESERVOIR (in acre-feet) Uniform release operation : Rapid release operation Reservoir storage capacity Available to' Oxnard For&tay, Oxnard Pla!n end PUaaent Valley Subunits, with releases for maintenance of ground water levels Available to Oxnard : Forebay, Oxnard t Plain, and Pleasant : Valley Subunits, : without releases : for maintenance of : eround water levels : Available within t Santa Clara River : Hydrologic Unit : Available to Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits 25,000 50,000 U,000 9,500 5,800 11,300 It, 100 9,600 3,000 8,000 As a result of the geological investigation and the reservoir yield studies, estimates of cost were prepared for two dams at the Hammel site with heights of 330 feet and U28 feet from stream bed to top of spillway gates, creating reservoir storage capacities of 25*000 and 50,000 acre-feet, respective- ly. For both dams, a concrete gravity structure was contemplated. The dams would have crest widths of 30 feet, 0.8:1 downstream slopes and 0.05:1 upstream slopes, except that the upstream slope for the higher dam would be 0.5:1 below an elevation of 823 feet* The two dams would have crest lengths of U70 feet and 810 feet, respectively* In the cost estimates, it was assumed that the talus and a depth of about 15 feet of jointed rock would be stripped from the right abutment up to an elevation about 75 feet above stream bed. Above this elevation, about 3 feet of soil and talus and 30 feet of rock would be removed. In the channel section, a depth of about 25 feet of gravel, boulders, and blocks up to 30 feet in dia- meter, would have to be removed. It was assumed that a cut would be made in the cliff which forms the lower portion of the right abutment. The cut would be about 15 feet in depth in its lower half, and about 25 feet in depth in the upper half. Above the top of the cliff, approximately 250 feet above stream bed, the cut would be increased in depth to about 30 feet to include removal of weathered surficial materials* 4-85 Spillways, for both heights of dam considered, would have a dis- charge capacity of 90,000 second-feet, which is the estimated peak discharge of a one in 1000-year flood. The spillways would consist of a concrete overpour section in the center of the dam, and would be provided with four tainter gates, each 30 feet high and UO feet wide. Maximum depth of water above the bottom of the gates would be 30 feet, and an additional 5 feet of freeboard would be provided. A spillway bucket would be provided at the down- stream toe of the dam to deflect the high velocity flood flows into the air, A roadway, 10 feet in width, would be located on the crest of the dams and across the spillway near the upstream face, for access to the tainter gate controls. Water would be released from the reservoir into a £h-inch diameter steel outlet pipe, located through the dam near the left abutment at an elevation of approximately 910 feet. The outlet pipe lengths would be 180 feet and 2^0 feet for the lower and higher dams, respectively. Releases would be controlled by a lj3-inch diameter needle valve and a high pressure ring seal gate. A 5U-inch diameter sluiceway pipe would be provided through the center of the dam at an elevation of 800 feet* The sluice pipe would be 310 feet in length for the lower dam and bOO feet in length for the higher dam, and would be controlled by two high pressure ring seal gates. Steel trashrack structures would be provided at the upstream ends of the outlet and sluice pipes, and access to the controls would be through chambers provided in the dam. It was estimated that construction of a dam, either of 330 or U28 foot height, at the Hammel site would require about two years. Diversion of summer and small winter stream flows during construction would be through a 7-foot diameter concrete lined tunnel of horseshoe section located through the left abutment* Major floods would pass over a depressed section of the concrete dam. The diversion tunnel would be about h90 feet in length for the lower dam and about £60 feet in length for the higher dam. Following construc- tion, the tunnel would be plugged at the upstream end* Aggregate for a concrete dam could be imported to the Hammel site by truck or rail. Rail haul to within about five miles of the site is avail- able. The aggregate could come from sources along the Santa Clara River area from 7 to 20 miles distant. After suitable testing, it might be determined that rock near the dam site is usable after crushing and screeningo It was estimated that from 210 to 320 acres of clearing would be required in the reservoir are?., depending on the height of dam to be constructed. There are no improvements in tha area. Approximately 170 acres are under private ownership^, while the remainder of the property belongs to the Federal Government, In 19!?2, the cost of acquisition of private lands in the reservoir area was estimated by the Ventura County Flood Control District to be about $12,f>00 for both sizes of dam<> Construction of an access road, approximately 2 miles in length, would be required before construction could start. Presented in Table 77 are pertinent data with respect to the general features of the two sizes of dams and reservoirs considered at the Hammel site, as designed for cost estimating purposes. For illustrative purposes, a plan, profile, and section for the dam creating a reservoir with storage capacity of $0,000 acre- feet are shown on Plate 30, entitled "Hammel Dam on Sespe Creek", 4-87 TABLE 77 GENERAL FEATURES OF TWO SIZES OF DAM AND RESERVOIR AT THE HAMMEL SHE ON SESPE CREEK Concrete Gravity Dam Crest elevation, in feet, U.S.G.S. datura Crest length, in feet . . Crest width, in feet. . . Height of dam, to top of spillway gates above stream bed, in feet. . . Freeboard, above top of spillway gates, in feet. Elevation of stream bed, in feet, U.S.G.S* datum. Volume of concrete in dam, in cubic yards 1,125 1*70 30 330 5 790 530,700 Reservoir Surface area, at top of spillway gates, in acres • 200 Gross storage capacity, at top of spillway gates, in acre-feet 2^,000 Type of spillway Overpour, with gates and bucket Spillway discharge capa- city, in second-feet . . . 90,000 Type of outlets ...... 51+- inch diameter steel pipe through dam, and 51+-inch diameter steel pipe sluiceway 1,223 810 30 U28 5 790 1,067,900 308 50,000 Overpour, with gates and bucket 90,000 51+-inch diameter steel pipe through dam, and 51+- inch diameter steel pipe sluiceway U-88 Presented in Table 78 is a summary comparison of capital and annual costs of the two considered sizes of dam and reservoir at the Hammel site. Also presented in Table 78 are estimated unit costs of storage capacity and net safe yields of water that would be developed by construction of the two sizes of reservoir. Yields referred to are those that would result under the uniform release method of reservoir operation with releases for maintenance of historic ground water levels. Certain of the relationships presented in Table 78 are de- picted graphically on Plates 35, 36, and 37. Detailed estimates of cost for the two sizes of dam and reservoir at the Hammel site are included in Appendix C. TABLE 78 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE HAMMEL SITE ON SESPE CREEK Reservoir storage capacity, in acre-feet 25,000 50.000 Capital Costs Dam and reservoir Cost per acre-foot of storage Cost per acre-foot of net safe yield Annual Costs Dam and reservoir Cost per acre-foot of net safe yield Cost per acre-foot of incremental net safe yield $12,890,000 $24,490,000 516 490 3,220 2,580 666,000 1,252,000 166 132 107 4-89 Fillmore Dam and Reservoir. The Fillmore dam site, the lowermost of all sites considered on Sespe Creek, is located in Section 13, Township 4 North, Range 20 West, S.B.B. & M., about two miles north of the town of Fillmore and about 3*2 miles upstream from the confluence of Sespe Creek with the Santa Clara River. Stream bed elevation at the site is about 490 feet, U.S.G.S. datum. The location is such that practically complete regulation of the flow of Sespe Creek could be achieved through construction of a reservoir of sufficient size. Con- sideration was given to the construction of a dam and reservoir at the Fillmore site for storage of flood waters in Sespe Creek, and utilization of the waters so conserved in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. The drainage area of Sespe Creek above the Fillmore dam site comprises about 259 square miles, and produced an estimated average seasonal runoff during the base period of about 96,700 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 77,400 acre-feet per season during the base period with the present pattern of land use and water supply development. The Fillmore dam site was surveyed by the Ventura County Flood Control I District in 1951, using instrumental methods. The map resulting from this survey is at a scale one inch equals 200 feet, with a contour interval of 2 feet on flat areas and gently sloping hill sides, and 25 feet on steep hill sides. The map extends up to an elevation of 850 feet on the right abutment and 800 feet on the left abutment. An area-capacity curve for Fillmore Reservoir, data for which were obtained from U.S.G.S. quadrangles, at a scale of 1:24,000, was provided by the Ventura County Flood Control District. Storage capacities of Fillmore Reservoir at various stages of water surface elevation taken from this curve, are given in Table 79. h-90 TABLE 79 AREAS AND CAPACITIES OF FILLMORE RESERVOIR : Water surface Depth of water : elevation : ' Water surface i : Storage capacity, at dam, in feet : ! U.S.G.S. datum, 1 area, in acres : in acre-feet In feet 3 h90 10 500 22 110 '<. ~ 510 52 U80 30 520 100 1,21*0 1:0 530 170 2,600 ^0 Sko 210 14,530 60 550 260 6,890 70 560 320 9,790 80 570 380 13,300 90 580 IjlO 17,300 100 590 U5o 21,500 110 600 ii80 26,200 120 610 520 31,200 130 620 560 36,600 J&O 630 600 U2,U00 150 6^0 61*0 U8,700 160 650 700 55,iiOO 170 660 770 62,700 172 662 780 6^,300 180 670 820 70,700 190 680 870 79,100 200 690 900 88,000 210 700 935 97,200 211 701 9U0 98,100 220 710 960 107,700 230 720 980 116,1*00 2U0 730 1,000 126,200 250 Iho 1,0U0 136,300 260 75o 1,070 lii6,900 261 751 1,080 li;7,900 270 760 1,110 157,800 280 770 1,150 169,100 290 780 1,190 180,800 300 790 1,220 192,900 310 800 1,260 205,300 h-91 Based upon available geological information, including that resulting from reconnaissance examination and seismic surveys during the investigation, it was concluded that the only types of dam possible at the Fillmore site are earth- fill or rockfill structures. Furthermore, the construction of such types of dam would only be feasible if further tests of the stability of the right abutment should give necessary results. Geology in the area of the Fillmore dam site has been mapped by Kew, Hoots, Eldridge for the oil industry, and the geology of the more recent water- bearing deposits was reported on by Gentry in Division of Water Resources Bulletir No. 46. Much detailed work has been done on the older rock formations since publication of the aforementioned papers, but little has been done with the more recent water-bearing materials. Rocks exposed on the left abutment and in the left channel section a few hurdred feet downstream from the axis of the dam are Miocene Modelo shales and siltstones, generally fine grained, thin bedded, and laced with slip or shear zones and gouge streaks. Material exposed over the wide gently sloping terrace between the shale and the right abutment appears to be old deposits of sand, gravel, and boulders, with a relatively thin soil cover. At the stream channel, a depth of from 15 to 20 feet of boulders and smaller fragments, and about 4 feet of overlying soil is visible at the edge of this terrace. The right abutment, whose base is at an elevation about 100 feet above the stream bed, appears to be a portion or remnant of an old alluvial cone or terrace deposit, now considerably dissected. The materials comprising this abutment are generally unstratified, unsorted, and poorly consolidated. They consist of varying proportions of sandy and clayey material, containing rock fragments which vary in size to large subangular blocks. The upper surface of the abutment is relatively even and gently sloping, and supports a light brush an< tree growth. The steep dissected side slopes have a heavy brush cover, 4-92 The San Cayetano thrust fault has been mapped by Kew and others, extending in a north-northwesterly direction near the center of the channel section at the Fillmore dam axis. The northeast limb of the fault is upthrown. If this mapping is correct, the iiodelo shale of the left abutment dees not extend to the west (right) of the fault, except at great depth. Two 8-inch cable tool holes were drilled, and a seismic profile run iby the Division of Water Resources to establish the presence or absence of the Iiodelo shale at shallow depths on the low right abutment terrace, and, if the shale was found to be absent, to determine whether other impervious materials suitable for a dam foundation were present. One hole was located on the sloping terrace near the base of the right abutment at an elevation about 35 feet above stream bed, and the other in the lower part of the sloping terrace at a site about 350 feet from the edge of the channel section, at an elevation about 20 feet above stream bed. The hole near the right abutment was drilled to a 60- foot depth, and the lower hole to a 67- foot depth. Neither of these holes encountered I shale or comparable material, nor did they strike water table. They did, however, strike fairly tight silt and silty clay, commonly containing sand and pebbles, i almost continuously from a few feet below the surface to the bottom of the holes. This material is apparently terrace material similar to that composing the right abutment . Seismic profiles were run by the Division of Water Resources, from the shale exposed in the channel section upstream to the axis, where the shale is under the gravels, and thence along the axis of the dam toward the right abutment as far as Grand Avenue. Another profile was run a short distance along Grand Avenue both upstream and downstream from the axis. This survey indicated the seismic velocity in the shale at the ground surface to be about 6,000 .feet per second. Materials with velocity up id 7,000 feet per seccad (probably saturated shale) were found underlying the gravels of the active channel section. Material of ^-93 similar velocity was found to extend to Grand Avenue along the profile line, but at increasingly greater depths. Depths varied from zero in the channel section t about 100 feet at the hole in the lower terrace, and 200 feet at the intersection of the axis and Grand Avenue. This material may be saturated tight terrace material similar to that encountered in the drill holes. There are indications that this high velocity material may be pitching off in a downstream direction. A material having still higher velocity, on the order of 11,000 feet per second, was picked up toward the right abutment from the stream channel. This appears to have the seismic velocity of a consolidated sandstone, and may represent a small portion or fault sliver of Pico sandstone such as is exposed at the surface about a mile upstream. About one-half mile downstream from the Fillmore dam site, an oil company has drilled through approximately 12,000 feet of more recent sediments without encountering the Modelo shale. Evidence from this well, from the shallow drill holes on the axis of the dam, and from the seismic profiles indicates that the mapped location of the San Cayetano thrust fault in the channel section near the left abutment is correct, and that there is little chance of finding the Modelo shale at any reasonable depth at the dam site to the right of the fault. Records of runoff at the Fillmore dam site are not available. However, runoff at the site was estimated as equal to 102 per cent of the measured runoff at the U.S.G.S. stream gaging station on Sespe Creek near Fillmore, adjusted for diversions made upstream from the gaging station by the Fillmore Irrigation Company. The estimates were based on the ratio of respective watershed areas above the dam site and gaging station. The estimated monthly runoff of Sespe Creek at the Fillmore dam site during the base period is presented in Table 80. 4-94 -p o o o o o to CM H tf\ -4 0- rH rH •\ «\ *v «\ -d- coj>- co t>- -4 -4 c^ H cm a o o o o o 00 H CO CO *\ *\ «\ *\ *S co co CO >0 UN CO -4" O- ~4 to CO r-i H O Q O O O CO -4nO ^0 CM o- cm cm cm cm »\ »\ *N 9\ *\ irwo to Oc- o CO tf\ CO o CO •\ 0> CO o o o o O O O J>- H CO o o o o o O CO CO CO o 00 -4nO CO CO O Q O O O -3-co t> -4 o COOl H rH CM o 3 § (1) O O O Q O CO -4" o t> -4" -^t co o o o o O O CM tr\ CM COO CO H cm oo o p -4 CM O CO C-OrK) «\ «\ «t CM -trH o o o o o CM sO -4 CO Oi >A-4-t0r|lA CM H O O O O O vOvO vo -4 CM OnO CM O C^ CO rH H O O O Q O t> -4- CO -4 O- CM -4" CM C- CO *\ «\ «n, r\ *\ O rH CM CO rH O O O O O O O OvO C*- 40JHHH o o o o o O CO CM CO H to CO CM H CM O O O O O O O H CO to H tr\ u^ CO CO O o o rH O tr\ rH Q W M CO Q ph E-< <4 CO m co I a 1 -P CM H O O O O toco tr\ oo J>H CO CM *V 9\ •* ' ** to-^co o o o o COCO -4" CO O O 00 CM •\ *\ «-\ #\ cm -4 o m tf\CO H o o o o rH CO CM rH r>- CO On CM #\ »\ »\ «\ 40 4ia nO c-~ h o o o o ON H CO to cOCi rH CM 9\ «\ #s •! H C^ 'OO CO O O O O toco r>- o o o cm o #\. *\ «\ »\ -4 CO O rH H O O O O vO On O CM nO IS CO On O O O O O -4 C^- C>{>- CM H rH H sO -4 •% rv *\ rs #s t>- CO -4nO CM rH O O O Q O Oj> CO O E> -4 00 -4 -4 C- •\ * #* *% *% CO On CO u> to vO rH o o o o o On COCO CM -4 co c-- o r> on 0S *\ *\ +* »\ sQ CO ^ CM O tfNvO H a o o o o o t»^OH On vO nO Cn- O *\ *s «\ *\ *v rH CO O 00 H O coco CM o o o o o r- On tr\ tr\ ir\ H vO J> On C^- «\ «\ «\ «\ A •4- to ON -d rH CO tr\ O O O O O H tr\ [> iA -4 O O C- CO H OD O rH H CO CM O O O O O O -4 O O sD 40 lAOOc- o o o o o 00 On rH -4 H rH O O C--C0 CO rH o o o o o 00 nO cm <}• CO o- r- on coco *-. «\ #\ «N »N -4- H H H H O O O O O OJHl>c-0 00 -4- !>- co r>- On CM rH COrH H O O O O H -4vO CO oco C^ o CO CM vO o o o o o tO rH CO -4 On O r-- vrs r>- co CM tTN CO O O O Q O C*- CM On ~t nO O O -4 tn co 00 On H rH rH O Q O O O O -4 rH -4-4 00 tA CO CM -4 O -4 CO O CM tr\ O -4 O NO -4 O CO o NO CM O tr\ CM CM vO a -P o O o o o o CM H CO CM O sO CM O CO rH H O O O O O rH rH -4- 00 -4 -4 On -4 nO On o o o o o rH H O H CO ITS -4" CO CM H O o CM C C t/j -co on o CO CO CO -4 i I 1 I nC !> • CC On 0"» r 1 ^. CO CO O U-- On On H H H rH ci CM CO -4 tTN I I I I O^ On ON On On H H H H rH nO Cn-CQ On O -4 -4" -4 -4 tr\ I I I I I tOvO CO On -*-4-4 -4 -4 On On On On ON r-\ r-\ r-\ r-{ r-\ H UN, o tr\ On rH 4-95 Based on the estimates of runoff, monthly studies of operation of Fillmore Reservoir during the base period were made for three sizes of reservoir, of 64,000 acre-feet, 98,000 acre-feet, and 148,000 acre-feet storage capacity, under both the uniform release and rapid release methods of operation. In all of the studies, an allowance was made for reduction in effective reservoir storage capacity due to sedimentation, in the amount of 12,000 acre-feet. This amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 1.70 feet, distributed in accordance with the following tabulation, was employed in the operation studies. Net evaporation, Net evaporation, Month in feet of depth Month in feet of depth October 0.15 April 0.15 November 0.06 May 0.19 December 0,04 June 0.21 January 0.04 July 0.25 February 0.05 August 0.25 March 0.10 September 0.21 TOTAL 1.70 The estimated values of net safe seasonal yield that would be obtained under both the uniform release and rapid release operating criteria are presented in Table 81. The relationship between reservoir storage capacity and net safe seasonal yield, with Fillmore Reservoir operated by the uniform release method with releases for maintenance of water levels in Fillmore and Santa Paula Basins, is depicted graphically on Plate 36. 4-96 TABLE 81 ESTIMATED NET SAFE SEASONAL YIELDS OF FILLMORE RESERVOIR (In acre-feet) i Uniform release operation : Rapid release operotion """' : Available to Oxnard* Available to Oxnerd t : * Forebay, Oxnard » Forebay, Oxnard t » Available to Oxnard Reservoir storage* Plain, and Pleasant: Plain, and Pleasant » Available within s Forebay, Oxnard capacity * Val ley Subunits, s Valley Subun its, : Santa Clara River: Plain, and Pleasant : toitn releases * without releases : Hydrologic Unit s Valley Subun its s for maintenance of: for maintenance of s « : ground water levels* ground water levels : » 6U.00O 12,500 15*000 12,700 10,500 98,000 20,000 2U,000 20,500 15.500 ll»8,000 27,000 52,000 27,500 16,000 Although the Fillmore reservoir site affords an opportunity for the greatest degree of control of runoff from the Sespe Creek watershed, to achieve such control an earth or rock fill dam of considerable length would oe required. Since suitable foundation material was not encountered at moderate depths, it was concluded that to extend the impervious section of a suitable dam bo the underlying shale bedrock would not be feasible. Any structure contemplated at the Fillmore dam site would necessarily be floated on the terrace material Dverlying bedrock, using a shallow and narrow cutoff to reduce underflow. The ligh degree of development prevailing in the Fillmore Reservoir area would make acquisition of the necessary lands very expensive. For these reasons,, it was concluded that construction of a dam and reservoir at the Fillmore site is not feasible at the present time. Therefore, design of the dam and appurtenant features, and estimates of costs, were limited to those of a reconnaissance lature necessarily made to arrive at the foregoing conclusion. Reconnaissance type cost estimates were prepared for three earth- fill dams at the Fillmore site with heights of 172 feet, 211 feet, and 261 feet from stream bed to spillway lip, creating reservoir storage capacities Df 64,000 acre-feet, 98,000 acre-feet, and 148,000 acre-feet, respectively. For all heights of dam a rolled fill structure was contemplated, with upstream and 4-97 downstream slopes of 3:1, and a crest width of 30 feet. An open cut spillway, including an ogee weir section and a concrete lined chute, could be constructed across the left abutment. The cost estimates were based upon a freeboard of 10 feet from spillway lip to crest of dam. A depth of about 5 feet of weathered material in the root zone should be stripped from the right abutment under the impervious section of an earthen dam. Depths of 5 to 10 feet of terraced material should be similarly stripped from the right side terrace. Gravel and boulders to a depth of 10 feet should be removed under the impervious section from the active channel, about 6(X feet in width, and a depth of about 5 feet of weathered shale and silt stone should be removed from this vicinity where it is exposed. Practically all ex- cavated materials could be salvaged. A depth of about 12 feet of boulders and gravel should be stripped under the impervious section from the low terrace on the left abutment, plus about 2 feet of fractured shale beneath these gravels and boulders. The bouldery fill should be similarly stripped from the upper terrace to a depth of about 20 feet. At least 70 per cent of this material would be recoverable for impervious section. Materials taken from the terrace deposit upstream from the right abutment appear to be the main source of materials for an impervious section neai the Fillmore dam site. About one-third of this material would have to bescreenec to eliminate the boulders and large blocks, which could then be salvaged for blanket material. Compaction and permeability tests indicated that careful selection, and possible blending of materials, would be necessary to construct a suitable impervious fill from the terrace deposit. In addition to the materia] of the right abutment, it is possible that the soil and underlying sediments of the low terrace between the right abutment and the channel section might be usable. Also, the material of the upstream terrace on the left abutment appears tc be similar to that tested from the right abutment, and should be usable. Removal 4-9S )f trees, stumps, and roots might present a problem as to the suitability of ihis material. Pervious fill material is available in limited quantities in :he channel of Sespe Creek both upstream and downstream from the axis of the dam, ind large quantities of similar material could be obtained from the Santa Clara iliver channel about three miles downstream. The nearest heavy rock or riprap naterial available appear to be hard red Sespe sandstone located about three uiles upstream near the Hammel Dam site. The Fillmore reservoir area, to a distance of about 1.5 miles upstream from the dam site, contains several hundred acres of mature orange groves and suburban residences, and a number of oil rights and leases. Two county roads would be flooded and depending on the size of dam, several existing oil wells might possibly be inundated. A preliminary appraisal report prepared by the Ventura County Flood Control District in September 1951, estimated that the fair market value of property that would have to be acquired for construction of Fillmore Dam and Reservoir was $2,155,600. Presented in Table 82 is a summary comparison of capital and annual costs of the three considered sizes of dam and reservoir at the Fillmore site. Also presented in Table 82 are estimated unit costs of storage capacity and net safe yields of water that would be developed by construction of the three sizes of reservoir. Yields referred to are those that would result under the uniform release method of reservoir operation with releases for maintenance of historic ground water levels. It is emphasized that the estimated costs are of a reconnaissance nature. 4-99 TABLE 82 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT FILLMORE SITE ON SESPE CREEK Item Reservoir storage capacity, in acre-feet 61+, OOP ; 9b, OOP ; 1U8,0Q0" Capital Costs Dam and reservoir Cost per acre-foot of storage Cost per acre-foot of net safe yield Annual Costs Dam and reservoir Cost per acre-foot of net safe yield Cost per acre-foot of incremental net safe yield ^18,966,000 $28,352,000 296 289 1,520 1,1*20 $14*, 680, 000 302 1,650 968,000 1,Ui5,000 2,273,000 77 72 8U 6U 118 U-100 Upper Blue Point Dam and Reservoir . The Upper Blue Point dam site is ocated on Piru Creek in Section 10, Township 5 North, Range 18 West, S.B.B.&M., ome ten miles upstream from the confluence of Piru Cresk and the Santa Clara iver. Stream bed elevation at the site is about 1,090 feet, U.S.G.S. datum, he drainage area of Piru Creek above the Upper Blue Point dam site comprises bout 370 square miles, and produced an estimated average seasonal runoff during he base period of about U8,700 acre-feet. It was estimated that waste to the cean of water originating above the dam site would have averaged about 32,800 cre-feet per season during the base period with the present pattern of land use ,nd water supply development. Consideration was given to the construction of a dam and reservoir at .he Upper Blue Point site as one of the several possible alternative locations 'or terminal storage of water imported from the Sacramento-San Joaquin Delta, 'his reservoir would regulate such water released from the southern California ii version conduit of the Feather River Project at a point near Quail Lake. The ^leased water would flow through conduits and down natural stream channels, itilizing power drops for the generation of hydroelectric power, en route to Jpper Blue Point Reservoir. In the reservoir, the water would be available to leet ultimate supplemental water requirements throughout Ventura County. Consi- ieration was also given to use of Upper Blue Point Reservoir for storage of flood waters of Piru Creek, and utilization of the waters so conserved in the Calleguas- 3onejo Hydrologic Unit and in the Oxnard Forebay, Oxnard Plain, and Pleasant falley Subunits of the Santa Clara River Hydrologic Unit. The Upper Blue Point Reservoir area was mapped in 1951 by Fairchild Serial Surveys, Incorporated, using photo gramme trie methods, for the Ventura bounty Flood Control District, Zone 2. The resulting map is at a scale of L inch equals ii00 feet, with a 10-foot contour interval. An enlargement of the reservoir map in the vicinity of the dam site, to a scale of 1 inch equals 100 U-ioi feet, was used for design of the dam and cost estimating purposes. Data on reservoir areas and capacities for various heights of dam were furnished by the Ventura County Flood Control District, and were based upon the aforementioned map of the reservoir area. Storage capacities of Upper Blue Point Reservoir at various stages of water surface elevation are given in Table 83. U-102 TABLE 83 AREAS AND CAPACITIES OF UPPER BLUE POINT RESERVOIR Water surface Depth of water elevation Water surface . Storage capacity, at dam, in feet U.S.G.S. datum, in feet area, in acres : in acre-feet 1,090 10 1,100 15 78 20 1,110 23 270 40 1,130 68 1,170 60 1,150 140 3,220 80 1,170 180 6,400 100 1,190 230 10, 500 110 1,200 250 12,900 130 1,220 300 18,400 150 1,240 350 24,900 160 1,250 380 28,500 170 1,260 410 32,400 190 1,280 490 41,400 205 1,295 540 50,000 210 1,300 560 51,900 230 1,320 590 63,500 260 1,350 750 83,700 280 1,370 820 99,500 310 1,400 930 125,800 As a result of preliminary geological reconnaissance, it was concluded ;hat an earthfill dam of moderate height is the most feasible at the Upper Blue >oint site, and that a high earth or rockfill dam or a masonry dam would be of loubtful feasibility. No geologic work at this site is known, other than the >reliminary reconnaissance made in 1952 by geologists of the Division of Water Resources. The Upper Blue Point site is located at a constriction in the canyon if Piru Creek. The rock includes light brown sandstone, varying from massive to .hin bedded, and some shale. Massive sandstones are very prominent on the right ibutment, whereas thinner bedded sandstones are prominent on the left abutment, 1 though some massive rock is there also. A few beds of shale appear, particularly WQ3 on the left abutment. Concentrations of ferruginous material approaching con- cretions appear in numerous places in the sandstones. The left abutment is a fairly narrow nose falling back sharply down- stream and somewhat less sharply upstream. The strata on the left abutment are overturned. They strike approximately across the channel and dip very steeply upstream. A similar attitude occurs in the upstream portion of the right abut- ment. However, south of a fault, which extends down the ravine opposite the approximate center of the left abutment face, the strike is cross-channel, and the strata dip downstream and toward the left abutment at a much gentler angle. The aforementioned fault trends southeasterly from the ravine on the right abut- ment, crosses the channel section, and probably lies just south of the left abutment face. Farther east, strong evidence of this fault appears in disturbed beds in the walls of the canyon extending eastward south of the left abutment face . The sandstones on the left abutment are cut by a great number of fracture planes, trending in many directions. The fracture planes have been most3.y re-cemented with limonitic material. The sandstones on the right abutment south of the fault appear to have been much less fractured, perhaps because of their massive nature. North of the fault on the right abutment, fracturing of the rocks is similar to that on the left abutment. Open joints are much more numerous on the left abutment, and on the right abutment north of the fault, than on the right abutment south of the fault. Records of runoff at the Upper Blue Point dam site are not available. However, runoff at the site was estimated as equal to 85 per cent of the measured runoff at the U.S.G.S. stream gaging station on Piru Creek near Piru. The estimates were based on the ratio of respective watershed areas above the dam site and gaging station. The estimated monthly runoff of Piru Creek at the Upper Blue Point site during the base period is presented in Table 84. It may 4-104 be noted that runoff at the Blue Point site, about 1,700 feet downstream was assumed to be the same as that at the Upper Blue Point site. 4-105 -P o E-t o o o o CM UN CO O CM 44UN #* n 9\ w\ ON CN CM vO H Q O O O O no r- on on CM on cnMD _d CM •\ #\ •* ^ *\ CM c^-^O MD On On CM CO O CM O O O O O CO ON_d rr\ on -ct r-|vO H H »\ •% *\ •* #\ C^-4UNU\vO CM CM o CM O Os NO 4 -P a CD CO o o o o CM CO H ON rH 00 CO CM O O Q O O 40*ococo 4 ON4cO rr\ O O O O O MD rH r>-U\U\ CM H O UN id CM On O UN HOW O O O Q O CM On CM vO UN NOJ\AOn O O Q O O O On NO no UN ON O 4 1 ,=3 O Q O O CO M3 ^- On CM rH CM O O O O on on On On On rH UN CM •\ CM o o o o ON On CM CO CO H UN r~- . #\ *% «\ cM_cr h o o o o o CO UN H On r>- CM rH O O O O O C>-4 ON CM M3 vO ON_dCO O 1A H O^rH O O O O O CO NO C--44 _d rH ON_dCO UN CM CM On pH o o o o o J(n>- On UN P On o o p o o UN ON CM rH U\ r-- CM CM rH P CM H p O o o O On ON On CO H r— 0-4 CM r--\ P On H o •p o O o w co CO P O P o O P P O P O O P P O ncMh-\o (^ P t>- rH H On NO cm _dco MD CM CO 3-d NO CM onnO On r>. ON CM On nO C^ CM •^ «\ «\ *\ •l «t «t «\ #1 9\ »\ ON CO CM rH C^-4^0 C»- ON o-v H r-rH O O P p p p O O P rH CM ON r>- CM P O P P o Q r>-UN on4 O 4 On H O 3 NO CO CM UN On vO On rH On rH UNH f- On •\ «x »\ *> •\ •* n *\ «\ *\ *\ ^ rx CO o ^O CM NO CM CO ON_d UN rH rA H rH r- nO CM ON O O P p P O O P p O O P o p p H H C^ao O UNCO C^- UN CM fc- r^co H 4 ON UN O t^-OSCO CM UN C\ P CO P C— C— C— ON ON 1 •\ «t «t *\ »\ «\ «\ «\ «\ . •\ •» r> O O r*- cm no C*- CM NO ON t^- CM rH r-{ UN CM H 4 H CM On rH O P O P p o o p P p O P p P O 4 On cm co 4 O CM UN On 4co r-UNM3 r- 3 CO CNHf>- P HOO CM p CO HUN NO H CM O •\ •» •* •V *v *\ ^ •* •s *\ «\ | CM ~Zt rH co 4md on cm rH ON rH CM -P P P O P o p pp o On O P CM H O P P P P P ON ON CM NO H CM ON NO ONCO ON 1 CM _d O CO H C— CO CO rH On C>-nO nO C^- H NO •»•»•» •» «\ •» •» »> »\ ON ON rH ON UMJN. >=r CM VT\On On H OOOQ NO rH O P O P p p P O P O o P P »> P UNU\ f*N t*> ONOHW Pi «H H CM On f- ON f>- "UN CO UN On CO 4" rH rH «H •\ »i «% Q H 0\ ON ON c**\ j-^d_d-4-4- 44444 UN <4 On on On On On On On On On On On On On On ON rH rH rH rH r-\ rH rl r4 t-i rH rH rH rH rH H U-106 It was estimated that a reservoir storage capacity of approximately 50,000 acre-feet would be necessary for terminal storage and regulation of water imported from facilities of the Feather River Project. To determine the safe yield of Upper Blue Point Reservoir with this storage capacity, if used ifor conservation of Piru Creek flood waters, monthly studies of operation during the base period were made under both the uniform release and rapid release methods of operation. The studies were based on the estimates of runoff of Piru Creek. An allowance was made for reduction in effective reservoir storage capacity due to sedimentation, in the amount of 12,000 acre-feet. This amount represents the estimated loss after about 20 years of operation. An estimated average net seasonal depth of evaporation from the reservoir water surface of 2.20 feet, distributed monthly in accordance with the following tabulation, was employed in the operation studies: Month Net evaporation, in feet of depth Month Net evaporation, in feet of depth October 0.19 April 0.19 November 0.08 May 0.24 December 0.05 June 0.27 January 0.05 July 0.33 February 0.06 August 0.33 March 0.13 September 0.28 TOTAL 2.20 The operation studies indicated that under the uniform release method of operation a net safe seasonal yield of 6,500 acre-feet would have been avail- able to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, with sufficient reservoir releases to have maintained historical ground water levels in affected basins. Without such releases for maintenance of ground water levels, the net safe yield would have increased to an estimated 9,300 acre-feet per season. Under the rapid release method of operation, a net safe yield of 6,700 acre-feet per season would have been available within the Santa Clara River U-X07 Hydrologic Unit. However, under this method of operation only 4,500 acre-feet per season of net safe yield would have been available to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits. Estimates of cost were prepared for a dam at the Upper Blue Point site with a height of 205 feet from stream bed to spillway lip, creating reservoir storage capacity of 50,000 acre-feet. The dam would be a rolled earth- fill structure, comprised of an impervious core of select earth material, and upstream and downstream sections of pervious free-draining material. Both up- stream and downstream slopes of the dam would be 3 si, and the impervious section would have slopes of 1:1. The crest width of the dam would be 30 feet, comprised of a 10-foot width for the impervious core, and 10-foot widths each for the up- stream and downstream pervious sections. The upstream face of the dam would be protected against wave action by rock riprap placed to a depth of 3 feet normal to the slope. In the cost estimates, it was assumed that depths of about 4 feet of soil plus 4 feet of fractured rock would be stripped beneath the impervious section on the right abutment. Under the impervious section in the channel, a depth of about 60 feet of sand and gravel, including terrace material, would be stripped, and the exposed rock would be shaped. A depth of about 2 feet of soil plus 6 feet of fractured and weathered rock, including alluvial material, would be stripped from the left abutment. A prominent thin rock cliff at the southern end of the left abutment face might have to be removed, at least in part which removal was not included in the cost estimates. Further exploratory work and examination during construction would be required to determine the amount of stripping required on this cliff. Stripping under the pervious sections of the dam was assumed to be a nominal depth of 2 feet of loose surface material and vegetation. Earth materials considered suitable for the impervious section of the 4-108 dam occur in terraces both upstream and downstream from the site. Pervious material is available in the channel and in nearby sandy terraces. An estimated 60 per cent of the material stripped from the right abutment, nearly 100 per cent of that removed from the channel, and about 70 per cent of the material stripped from the left abutment could be used in the pervious section. The nearest source of riprap is a deposit of granite about three miles air line to the northeast of the dam site. It was assumed that compaction of the impervious section of the dam would be effected by either sheepsfoot tampers or pneumatic rollers, and that pneumatic rollers would be used to compact the pervious sections. It was also assumed that moderate grouting would be necessary to prevent minor leakage in the foundation and abutments. The spillway considered would have a discharge capacity of 100,000 second feet, which is the estimated peak discharge of a once in 1,000-year flood. The spillway was designed as a concrete-lined overpour chute, with an ogee weir control section. The spillway weir and channel would be excavated through the thin left abutment ridge, and would discharge into Piru Creek downstream from the dam. Depth of water above the spillway lip at design discharge capacity would be 20 feet, and an additional 5 feet of residual freeboard \/ould be provided. It was estimated that the Upper Blue Point Dam would require about two years for construction. A 20- foot diameter concrete lined tunnel of horseshoe section, 1,250 feet in length, was included in the estimate to permit the diversion of Piru Creek waters during the construction period. The tunnel tfould be constructed through the left abutment of the dam. After completion of the dam, the diversion tunnel would be used for the outlet from the reservoir. A concrete plug would be placed in the upstream end of the tunnel, and a 72-inch diameter steel pipe would be placed through ihis plug, extending to a circular reinforced concrete outlet tower located in k-109 the reservoir. Water would enter the tower through four 36-inch diameter inlet valves. The outlet pipe would be supported on ring girders through the tunnel and would terminate in a control house, where a bifurcation structure would be located to permit the discharge of water to either Piru Creek or a proposed conduit. The downstream releases would be controlled by a 48-inch diameter Howell-Bunger valve, and a 48-inch diameter needle valve would control releases to the conduit. The dam site and a portion of the land in the Upper Blue Point reservoir area are privately owned, while the remainder of the reservoir area belongs to the Federal Government and is a part of the Los Padres National Forest. Cost of acquisition of the private lands was estimated by the Ventura County Flood Contro] District in 1952 to be about «#33>300. There are no improvements which would have to be acquired or relocated. Field examination of the reservoir area indicated that approximately 640 acres of minor clearing would be required. Prior to con- struction of the dam, an estimated 1.5 miles of access road would have to be constructed, to replace an existing low standard road. Presented in Table 85 are pertinent data with respect to general features of the dam and reservoir considered at the Upper Blue Point 3ite, as designed for cost estimating purposes. For illustrative purposes, a plan, profile and section of the dam creating a reservoir with storage capacity of 50,000 acre- feet are shown on Plate 31, entitled "Upper Blue Point Dam on Piru Creek". ii-110 , TABLE 85 GENERAL FEATURES OF DAM AND RESERVOIR AT THE UPPER BLUE POINT SITE ON PIRU CREEK, WITH 50,000 ACRE-FOOT STORAGE CAPACITY ;Earthfiil Dam Crest elevation, in feet, U.S.G.S. datum 1,320 Crest length, in feet 1,110 Crest width, in feet 30 Height, spillway lip above stream bed, in feet 205 Side slopes, upstream and downstream ....3:1 Freeboard, above spillway lin, in feet 25 Elevation of stream bed, in feet, U.S.G.S. datum 1,090 Volume of fill, in cubic yards 4,986,000 Reservoir Surface area at spillway lip, in acres 542 Gross storage capacity at spillway lip, in acre-feet 50,000 Type of spillway Ogee weir and concrete lined chute Spillway discharge capacity, in second-feet 100,000 Type of outlet • Concrete tower, and 72-inch diameter steel pipe through diversion tunnel U-lll Presented in Table 86 is a summary of capital and annual costs of a dam and reservoir at the Upper Blue Point site, to create 50,000 acre-feet of storage capacity. Also presented are estimated unit costs of storage capacity and net safe yield of water. The yield referred to is that which would result under the uniform release method of reservoir operation with releases for maintenance of historic ground water levels. Detailed estimates of cost of the dam and reservoir are included in Appendix C. TABLE 86 SUMMARY OF ESTIMATED COSTS OF DAM, RESERVOIR,' AND YIELD OF V/ATER AT THE UPPER BLUE POINT SITE ON PIRU CREEK WITH 50,000 ACRE-FOOT STORAGE CAPACITY Capital Costs Dam and reservoir $8,530,000 Cost per. acre-foot of storage 170 Cost per acre-foot . of net safe yield ,1,310 Annual Costs Dam and reservoir 438,000 Cost per a ere -foot of net safe yield 67 4-112 Blue Point Dam and Reservoir. The Blue Point dam site is located on Piru Creek in Section 10, Township 5 North, Range 18 West, S.B.B. & M. , some ten miles upstream from the confluence of Piru Creek and the Santa Clara River, and approximately 1,700 feet downstream from the Upper Blue Point site. Stream bed elevation at the site is about 1,065 feet, U.S.G.S. datum. The drainage area of Piru Creek above the dam site comprises about 371 square miles, and produced an estimated average seasonal runoff during the base period of about 48,700 acre- feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 32,800 a ere -feet per season during the base period with the present pattern of land use and water supply development • Consideration was given to the construction of a dam and reservoir at the Blue Point site as one of several possible alternative locations for terminal storage of water imported from the Sacramento-San Joaquin Delta with facilities of the Feather River Project, as described in connection with Upper Blue Point Re- servoir in the preceding section. In Blue Point Reservoir, the imported water would be available to meet ultimate supplemental water requirements throughout Ventura County. Consideration was also given to use of Blue Foint Reservoir for storage of flood x^aters of Piru Creek, and utilization of the waters so conserved in the Calleguas-Conejo Kydrologic Unit and in the Oxnard Forebay, Oxnard Plain and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. The Blue Point dam site and reservoir area were mapped in 1951 by Fairchild Aerial Survey, Inc., using photogrammetric methods for the Ventura County Flood Control District, Zone 2. The dam site was mapped up to an elevation of 1,700 feet, at a scale of one inch equals 100 feet, with a contour interval of 5 feet. The reservoir area was mapped up to an elevation of 1,250 feet, at a scale of one inch equals 400-feet, with a contour interval of 10 feet. Data on reservoir areas and capacities for various heights of dam were furnished by Ventura County Flood Control District, and were based on the aforementioned map of the reservoir area. Storage capacities of Blue Point Reservoir at various 4-H3 stages of water surface elevation are given in Table 87, . TABLE 87 AREAS AND CAPACITIES OF BLUE POINT RESERVOIR Water surface Depth of water : elevation Water surface : Storage capacity, at dam, in feet : ' U.S.G.S. datum, in feet area, in acres : in acre-feet 1,065 5 1,070 1 3 15 1,080 5 32 25 1,090 11 110 35 1,100 33 330 45 1,110 45 720 65 1,130 98 2,150 85 1,150 170 4,870 105 1,170 220 8,830 125 1,190 270 13,800 135 1,200 300 16,700 155 1,220 350 23,200 175 1,240 410 30,800 185 1,250 440 35,100 195 1,260 480 39,700 210 1,275 540 48,000 215 1,280 560 50,000 235 1,300 640 62,000 255 1,320 730 75,600 285 1,350 850 99,300 305 1,370 920 117,000 Geology of the region at- the Blue Point dam site has been studied by Dr. Charles P. Berkey, Paul F. Kerr, Hyde Forbes, and Chester Marliave, and is described in Division of Water Resources Board Bulletin No. 46, published in 1933. The dam site has been explored by trenching on both abutments and by test hole drilling. Five holes were drilled in the stream bed, and four of these penetrated the stream gravels and were continued into bedrock. One hole was bored vertically into the right abutment at an elevation about 160 feet above the stream bed. The following is quoted from Bulletin No. 46 and was taken from a report by Chester JMarliave: 4-114 "It is believed that on account of foundation conditions, only a flexible type of dam with a broad base should be constructed at this site. No good rock for such type of dam is available in the immediate vicinity but material for an earth fill is found just be- low the dam site. The earth fill type was therefore selected as the most suitable for this roservoir "The region in the vicinity of the dam site is composed entirely of Tertiary sediments which are rather poorly cemented sandstones inter- bedded with clay shales. "The regional structure is somewhat complex, the sedimentary beds being considerably folded and in the vicinity of the dam site they are overturned. The intense folding which some of the beds have undergone has resulted in numerous sharp anticlines and synclines which are con- spicuous along the canyon in certain places. Accompanying these crustal movements there has been considerable local faulting and slipping, but no major faults were observed in this locality. "The bedrock at dam site shows a formational contact. The red beds of the Sespe formation merge into the light colored buff beds of the Vaqueros formation. At the contact there are several hard thin strata of calcareous sandstone about a foot in thickness that are much more resistent than the accompanying strata and act as protective layers preventing disintegration of the softer underlying beds. On account of the inclination of the beds these hard sandstone layers form projecting ridges on each side of the canyon. The softer Vaqueros sediments under- lying these harder strata weather easily so that there are high verti- cal bluffs on their downstream side. Resting upon these hard thin sand- stone strata are the red beds of the Sespe formation which are composed of alternating hard and soft layers of sandstone and shale occupying an area 700 feet upstream from the dam site. On either: side of the canyon the sedimentary beds dip uniformly upstream at an angle of $0 degrees from the horizontal, while the strike is at right angles to the direc- tion of the stream channel. "The channel section at the dam site is about 175 feet wide at the constriction of bluffs and somewhat wider along the axis of the dam site. The drill holes put down through the gravels show that bedrock under the stream bed lies close to 90 feet below the surface..- - - The material encountered in these holes where bedrock was reached is the same as that disclosed on the abutments of the dam site. "There appears to be a minor fault running along the stream bed under the dam site. - - - The straight uniform channel of the stream for a distance of '6,000 feet below the dam site is indicative of a fault, but its continuation upstream is not in evidence although the fault may merge into one of the intense folds.- "The main portion of the left end of the dam should be confined to the small depression upstream from the prominent outcropping rib of harder rock. Two minor faults occur across this abutment within the limits of the dam site. The sediments of the left abutment dip uniform- ly upstream in a monoclinal structure across the site. There is a large amount of talus material scattered along the bottom of the draw over which the proposed dam would rest. All of this loose material would have to be removed before any type of dam could be built at this site, "The right end of the dam should rest in the depression upstream from the prominent outcropped rib of the rock on that side of the canyon. Within the immediate limits of the dam site, the structure at this abutment is monoclinal but the upper portion merges into an in- clined syncline which is badly distorted and faulted. One fault traver- ses the abutment in a vertical direction at an elevation of about li;0 feet above the stream bed and has probably crushed the bedrock to a considerable extent. There is a large amount of talus material along the lower slope of this abutment resulting from the weathering of the Sespe formation higher up on the slope of the hill." Records of runoff at the Blue Point dam site are not available. Runoff at the site was assumed to be the same as at the Upper Blue Point Site, about 1,700 feet upstream. The method of estimating runoff at the Blue Point dam sites is described in the preceding section, and the estimated monthly flow of Piru Creek at the sites during the base period is presented- in Table 84o It was estimated that a reservoir storage capacity of approximately, 50,000 acre-feet would be necessary for terminal storage and regulation of water imported from facilities of the Feather River Project. To determine the safe yield of Blue Point Reservoir with this storage capacity, if used for conservation of Piru Creek flood waters, monthly studies of operation during the base period were made under both the uniform release and rapid release methods of operation. The studies were identical with those described in the previous section for Upper Blue Point Reservoir, and indicated that under the uniform release method of operation a net safe seasonal yield of 6,500 acre-feet would have been available to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, with sufficient reservoir releases to have maintained historical ground water levels in affected basins. Without such re- leases for maintenance of ground water levels, the net safe yield would have increased an estimated 9*300 acre-feet per season. Under the U-116 rapid release method of operation, a net safe yield of 6,700 acre-feet per season would have been available within the Santa Clara River Hydrologic Unit. However, under this method of operation only 4,500 acre-feet per season of net safe yield would have been available to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits. Estimates of cost were prepared for a dam at the Blue Point Site with a height of 215 feet from stream bed to spillway lip, creating reservoir storage capacity of 50,000 acre-feet. The dam would be a rolled earthfill structure, comprised of an earth core of select earth material, and upstream and downstream sections of pervious free-draining material. Both upstream and downstream slopes of the dam would be 3:1, and the impervious section would have slopes of 1:1. The crest width of the dam would be 30 feet, comprised of a 10-foot width for the impervious core, and 10-foot widths each for the upstream and downstream pervious sections. The upstream face of the dam would be protected against wave action by rock riprap placed to a depth of 3 feet normal to the slope. In the cost estimates, it was assumed that depths of from 15 to 90 feet of gravel and boulders would be stripped from the stream channel under the impervious section of the dam, and that the exposed rock would be shaped. Under the impervious section on the abutments, depths of from 5 to 30 feet of soil and decomposed rock would be removed. For the pervious sections of the dam, it was assumed that no stripping would be necessary, except for a nominal depth of 2 feet of loose surface material and vegetation. Earth materials considered suitable for the impervious section of the dam occur in terraces along Piru Creek near the site, and could be obtained from borrow pits located on both sides of the canyon about 1,500 feet downstream from the dam. The outer pervious zones of the dam would consist of stream bed sands and gravels, and materials salvaged from stripping operations. The nearest source of riprap is a deposit of granite about 3.5 miles to the north- 4-117 east of the dam site. It was assumed that compaction of the impervious section of the dam would be effected by either sheepsfoot tampers or pneumatic rollers, and that penumatic rollers would be used to compact the pervious sections. It was also assumed that moderate grouting would be necessary to prevent minor leakage in the foundation and abutments. The spillway considered would have a discharge capacity of 100,000 second-feet, which is the estimated peak discharge of a once in 1000-year flood. Because of the steep canyon walls on both abutments, any type of spillway placed across them would be extremely costly. For this reason, the spillway for Blue Point Reservoir was designed as a concrete lined tunnel, located through the left abutment. The control structure would consist of a concrete curved ogee weir, 310 feet in length. From the weir, the concrete training walls of the spillway would converge to a width of about 95 feet in a distance of 100 feet. At this point, a second ogee weir would control the flow entering the tunnel. The tunnel would be 1,075 feet in length, and would discharge into a concrete lined channel, 100 feet in length and thence into the channel of . Piru Creek several hundred feet downstream from the dam. The spill- way was designed to discharge 100,000 second-feet with the tunnel filled to 0.70 depth. With the flow at 0.93 depth, the spillway would discharge 130,000 second-feet, and flowing full it would discharge 120,000 second-feet. It was estimated that Blue Point Dam would require about two years for construction. Assuming that the spillway tunnel, outlet conduit, imperv- ious excavation, and embankment below the stream bed could be completed in one season, winter flood flows could be passed over the completed embankment without undue harm. The remaining embankment of less than 3,000,000 cubic yards could be placed in the next construction season, thus eliminating the necessity for a large diversion tunnel. It was further assumed that small summer flows could be diverted through the outlet conduit. U-118 The outlet works would consist of a circular reinforced concrete tower located in the reservoir, and a 72-inch diameter steel pipe, l,li50 feet in length, placed in a trench excavated in rock beneath the dam near the right abutment and encased in concrete. Releases from the reservoir would be controlled by four 36-inch diameter gate valves in the outlet tower. The outlet pipe would terminate in a control house downstream from the dam, where a bifurcation structure would be located, permitting the discharge of water to either Piru Creek or a proposed conduit. The downstream releases would be controlled by a i|8-inch diameter Howell-Bunger valve, and a U8-inch needle valve would control releases to the conduit. A portion of the land in the Blue Point reservoir area is privately owned, while the dam site and the remainder of the reservoir area belongs to the Federal Government and is a part of the Los Padres National Forest. Cost of acquisition of the private lands was estimated by the Ventura County Flood Control District in 1952 to be about &33j300. There are no improvements xdiich would have to be acquired or relocated. Field examination of the reservoir area indicated that approximately 6I4.O acres of minor clearing would be required. Prior to construction of the dam, an estimated 1.2 miles of access road would have to be constructed, to replace an existing low standard road. Presented in Table 88 are pertinent data with respect to general features of the dam and reservoir considered at the Blue Point Site, as designed for cost estimating purposes. For illustrative purposes, a plan, profile, and section of the dam creating a reservoir with storage capacity of 50*000 acre- feet are shown on Plate 32, entitled "Blue Point Dsm on Piru Creek." U--119 TABLE B8 GENERAL FEATURES OF DAM AND RESERVOIR AT THE BLUE POINT SITE ON PIRU CREEK, WITH 5^,000 ACRE-FOOT STORAGE CAPACITY Earthfill Dam Crest elevation, in feet, U.S.G.S. datum . 1,305 Crest length, in feet . . . . 830 Crest width, in feet » 30 Height, spillway lip above stream bed, in feet 215 Side slopes, upstream and downstream 3:1 Freeboard, above spillway lip, in feet 25 Elevation of stream bed, in feet, U.S.G.S. datum 1,065 Volume of fill, in cubic yards 3,497,700 Reservoir Surface area at spillway lip, in acres . 536 Gross storage capacity at spillway lip, in acre-feet 50,000 Type of spillway Tunnel Spillway discharge capacity in second-feet 100,000 Type of outlet Concrete tower, and 72-inch diameter steel pipe beneath dam. Presented in Table 89 is a summary of capital and annual costs of a dam and reservoir at the Blue Point Site, to create 50,000 acre-feet of storage capacity. Also presented are estimated unit costs of storage capacity and net safe yield of water. The yield referred to is that which would result under the uniform release method of reservoir operation with releases for maintenance of historic ground water levels. Detailed estimates of cost of the dam and reservoi are included in Appendix C. 4-120 TABLE 89 SUMMARY OF ESTIMATED COSTS OF DAM, RESERVOIR, AND YIELD OF YJATER AT THE BLUE POINT SITE ON PIRU CREEK, WITH 50,000 ACRE- FOOT STORAGE CAPACITY Capital Costs Dam and reservoir $8,171,000 Cost per acre-foot of storage. •* 160 Cost per acre-foot of net safe yield 1,260 Annual Costs Dam and reservoir 1*20,000 Cost per acre-foot of net safe yield .*... 65 U-121 Devil Canyon Dam and Reservoir. The Devil Canyon dam site is located on Piru Creek in Section 22, Township 5 North, Range 18 West, S.B.B. & M., some eight miles upstream from the confluence of Piru Creek and the Santa Clara River. Stream bed elevation at the site is about 980 feet, U.S.G.S. datura. The drainage area of Piru Creek above the Devil Canyon dam site comprises about 392 sr^ are miles, and produced an estimated average seasonal runoff during the base period of about 51,500 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 34,700 acre-feet per season during the base period with the present pattern of land use and water suppl; development. Consideration was given to the construction of a dam and reservoir at the Devil Canyon site as one of several possible alternative locations for ter- minal storage of water imported from the Sacramento-San Joaquin Delta with facilities of the Feather River Project, as was described in connection with Upper Blue Point Reservoir in a prior section. In Devil Canyon Reservoir, the imported water would be available to meet ultimate supplemental water require- ments throughout Ventura County. Consideration was also given to use of Devil Canyon Reservoir for storage of flood waters of Piru Creek, and utilization of the waters so conserved in the Calleguas-Conejo Hydrologic Unit and in t^e Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. Devil Canyon Reservoir, if constructed with sufficient storage capacity, could be used for joint regulation of imported water and conservation of local flood flows. The Devil Canyon dam site and reservoir area were surveyed in 1951 by Fairchild Aerial Surveys, Inc., using aerial photogrammetric methods, for the Ventura County Flood Control District, Zono 2. The dam site wa3 mapped up to an elevation of 1,450 feet, at a scale of one inch equals 100 feet, with a 5- foot contour interval. The reservoir area was mapped up to an elevation of 1,350 feet, at a scale of one inch equals 400 feet, with a contour interval at 10 feet. Data 4-122 on storage capacities of Devil Canyon Reservoir at various stages of water sur- face elevation, based on the aforementioned map, were obtained from the Ventura County Flood Control District and are presented in Table 90. 4-123 TABLE 90 AREAS AND CAPACITIES OF DEVIL CANYON RESERVOIR : Water surface : Depth of water 1 elevation : Water surface : Storage capacity, at dam, in feet 1 U.S.G.S. datum, : : in feet : area, in acres : in acre-feet 980 10 990 7 )*o 20 1,000 22 18. 30 1,010 10* 515 l*o 1,020 65 1,060 50 1,030 87 1,820 60 1,010 110 2,800 70 1,050 150 4,090 eo 1,060 210 5,670 90 1,070 260 8,200 100 1,060 290 10,900 110 1,090 320 11*, 000 120 1,100 380 17,500 130 1,110 1*15 21,500 lUo 1,120 1*70 25,900 150 1,130 530 30,900 160 1,11*0 590 36,500 170 1,150 61*0 1*2,700 180 1,160 690 1*9,300 190 1,170 71*0 56,500 200 1,180 800 61*, 200 210 1,190 850 72,1*00 220 1,200 910 81,200 230 1,210 960 90,500 2J4Q 1,220 1,020 100,000 2$0 1,230 1,080 110,900 260 1,21*0 1,150 - 122,100 270 1,250 1,210 133,900 280 1,260 1,280 11*6,300 285 1,265 1,310 153,000 290 1,270 1,350 159,1*0^ 300 1,280 1,1*20 173,300 310 1,290 1,500 187,900 320 1,300 .1,580 203,300 330 1,310 • 1,670 220,600 31*0 1,320 1,750 236, 700 350 1,330 1,830 251*, 600 360 1,31*0 1,910 273,1*00 370 1,350 1,990 292,900 4-124 Based on preliminary geological reconnaissance, the Devil Canyon dam site is considered best adapted to a rolled fill type of dam of moderate height. A geologic investigation of the site was made in 1951 as a part of the current investigation. The geology of the region and dam site was previously investi- gated for and is described in Division of Water Resources Bulletin No. 46. The recent geologic examination considered greater heights of dam than were con- templated in Bulletin No. 46. Foundation exploration prior to 1933 included the drilling of five drill holes and the sinking of two test pits. Further ex- ploration by the United Water Conservation District in 1952 included four drill holes. The abutments and foundation at the Devil Canyon dam site lie in an area occupied by the Modelo formation, here exemplified by a series of thin interbedded sandstones and shales. They are not well cemented or indurated, although leaching of soluble salts to the surface has hardened some of the beds. Where naturally exposed, some of the beds are strongly weathered, but road cuts made 20 years ago in the thin shaly beds show the material to be in generally good condition. The steep slopes have a relatively thin soil cover, and support only a slight growth of grass and brush. The bedding is markedly evident, par- ticularly on the left abutment. There is some evidence of openness along some I of the joints and bedding planes of the Modelo formation near the surface, part ' of which may be due to solution. Structurally, the dam site lies on the southerly limb of an east-west trending anticline, with the bed striking across the channel and dipping from 40 to 50 degrees downstream. The structure appears continuous, and no break is discernible in the channel section. The drill holes and test pits reported in Bulletin No. 46 showed the maximum depth of fill in the stream bed to be from 80 to 90 feet. The holes drilled in 1952 indicated that the depth of channel fill varied from 36 to 67 feet. 4-125 A small fault crosses the right abutment several hundred feet down- stream from the axis of the dam, but it is not considered active and should present no insoluble problem. Although a large earthen dam would overlap this fault, only the downstream toe would reach it, and it is believed that only moder ate additional excavation would be required. A few small seeps were noted near the base of the right abutment at the elevation of the road. Records of runoff at the Devil Canyon dam site are not available. How- ever, runoff at the site \-ia.s estimated as equal to 90 per cent of the measured runoff at the U.S.G.S. stream gaging station on Piru Creek near Piru. *iie esti- mates were based on the ratio of respective watershed areas above the dam site and gaging station. The estimated monthly runoff of Piru Creek at the Devil Canyon dam site during the base period is presented in Table 91. 4-126 H ON I 3 Q O W PL, o s M B EH M CO 8 | 3 rH > Q g H fa 5 E o PI CO -P Q) «\ «•> ONIAnO cm O O O O On CM XA O H CO H CM «\ *\ «\ •% CM H o o o o H 4 c-co O O fAco •\ #\ »\ •% O O O O CM O ONVO 4"LA"LAcO •\ *\ *\ fA H On O O O O r- cm ia4 o o o o o unco en c^-Hcoco c N00 0\0 o fA fA CYN4 w 1 1 1 1 cd NO C— CO On CO nnnn CO On On On On rH H H H o o o o o no ON c^-nQ On •t «l «\ «\ #\ fAco H cm o O CM On H fA CM H O O O O O cm cm ON-3--3- XA fA4 On o-\ O O O O H U\ cm I p— co rA^-A H fA 8 o o o o o J- co vO O On O\4co H fA CM CM o o o o o O On c- — 4" t*\ oosmoH MD H-CfiH O O O O O On ON4 O "LA •\ *\ •* *\ *\ NO CM fA O rH H H O O O O O NO O CM O CO -SHCO XACO «\ »N #\ «\ *\ onxamd co m fA H o o o o o "LA t>- On C-- H CO C--NQ 4 cm O CM fA4 O O O O O O C»- rA4 CM 9\ *\ 0\ *i 9\ O cm r-4co "LA H CM O O O O O H-d- O 4 H U\ fA44 CM CO -3" CO CM fA CM o o o o o ON4XA O fA 4 O oo H OJ »» »> «\ «\ "LAnQ \A CM o o o o o CM "LA CO CO 4 fACO "LA CO r- H fA o o o o o 4XA fACO H fA l>-_d-NO CM rH CM rA4XA 444JJ I I I I I O p-| CM fA4 44444 On On On On On rH rH rH H rH O O O O O On4 r-4"LA O "LA On4"LA •^ •* *\ *\ *» ONUMAIAvO CM CM o o o o o CO rH C^-IAIA CM H O O O O O CM ON NO NO "LA fA O O O O O O-4C0 O 1A -3 <-i H O O O O O On H fA CM "LA f>- fA CM H O O O O O On C"- CM O fA to C*-1A fA fA O O O O O nO O fA O f>- C- H rH O O O O O O fAM3 HUN 4- NO CM CO On #s *\ •% «\ 1A H H H CM o VA 4 O O o fA o o CM o fA CM O r- 4" 4 ■LA 1A o o o o o O O P- fAVTNNO XA CM CO CO P— O (A H #\ »\ *\ •LA CM H CM 1 O •LA On o o o o o O H 4 P~ O On fA CO On fANQ nO CM CM XJ 9\ »\ *\ UO rH CA H O O O O O O o •p C*- O O O- fA 4 CM fA C^-MD CO H p- »< »\ CA NO O 1 H MD fA ON O O O o o O H LA NO CM CM fA CM ON H 4 H H H »\ *\ «H Xf\ «H Q o o o o o O U Cnj On r>- p-vr\ NO CO 4 H H CO O W CC CD CO O nO p—co On O H to 4444m VA CTJ 1 I 1 1 1 | u "LA nO O-co On o o 4" 4- 4- 4-4 UN > On On On On On On 2, and their cost of acquisition was estimated to be $110,250. In the estimate, no valuation was placed upon mineral rights and oil leases. Presented in Table 95 are pertinent data with respect to the general features of the two sizes of dams and reservoirs considered at the Devil Canyon site, as designed for cost estimating purposes. For illustrative purposes, a plan, profile, and section for the dam creating a reservoir with storage capacity of 1^0,000 acre-feet are shown on Plate 33, entitled "Devil Canyon Dam on Piru Creek". h-13h TABLE 95 GENERAL FEATURES OF TW'O SIZES OF DAM AND RESERVOIR. AT THE DEVIL CANYON SITE ON PIRU CREEK Sarthfill Dam Crest elevation, in feet, U.S.G.S. datum 1,2U5 Crest length, in feet 1,050 Crest width, in feet 30 Height, spillway lip above stream bed, in feet 21*0 Side slopes, upstream and doiimstream . . . . 3:1 Freeboard, above spillway- lip, in feet 25 Elevation of stream bed, in feet, U.S.G.S. datum ..... 980 Volume of fill, in cubic yards 6,363,500 Reservoir Surface area at spillway lip, in acres * 1,021 Gross storage capacity at spillway lip, in acre-feet 100,000 Type of spillway Side channel and concrete lined chute Spillway discharge capacity, in second-feet ..... 102,000 Type of outlet 72-inch diameter steel pipe through diversion tunnel 1,290 1,180 30 285 3.25:1 25 980 9,888,900 1,315 150,000 Ogee weir and concrete lined chute 102,000 Concrete tower, and 72-inch diameter steel pipe through diversion tunnel U-135 Presented in Table 96 is a sunmary comparison of capital and annual costs of the two considered sizes of dam and reservoir at the Devil Canyon site Also presented in Table 96 are estimated unit costs of storage capacity and net safe yields of water that would be developed by construction of the two sizes of reservoir, with reservoir operation for the sole benefit of the Santa Clara River Hydrologic Unit under the uniform release operating criteria with release for maintenance of historic ground water levels. Certain of the relationships presented in Table 96 are depicted graphically on Plates 35, 36, and 37. De- tailed estimates of cost for the two sizes of dam and reservoir at the Devil Canyon site are included in Appendix C. TABLE 96 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT THE DEVIL CANYON SITE ON PIRU CREEK, WITH RESERVOIR OPERATION SOLELY FOR BENEFIT OF SANTA CLARA RIVER HYDROLOGIC UNIT Item Reservoir storage capacity, in acre -feet - 100,000 : 150,000 $12,120,000 $15,490,000 121 103 810 700 625,000 798,000 42 36 Capital Costs Dam and reservoir Cost per acre-foot of storage Cost per acre-foot of net safe yield Annual Costs Dam and reservoir Cost per acre-foot of net safe yield Cost per acre-foot of incremental net safe yield ... .. — • 25 Estimates of annual unit costs of net safe yields of water from a Devil Canyon Reservoir of 150,000 acre-foot storage capacity, with seven alternative sizes of Piru-Las Posas conduit, operated for the joint benefit of both the Santa Clara River and Calleguas-Conejo Hydrologic Units, are presented in Table 97. The estimates were based on the previously described 4-136 criteria of reservoir operation, including releases of water for the Santa Clara ^iver Hydrologic Unit by the uniform release method, and releases for maintenance of historic ground water levels in affected basins. TABLE 97 ESTIMATED UNIT COSTS OF YIELDS OF WATER FROM 1^0,000 ACRE-FOOT DEVIL CANYON RESERVOIR, WITH RESERVOIR OPERATION FOR JOINT BENEFIT OF SANTA CLARA RIVER AND CALLEGUAS-CONEJO HYDROLOGIC UNITS • Discharge capacity : of Piru-Las Posas Conduit, : Annual costs per acre-foot ^ in second- feet ; of net safe yield at reservoir UO $28 60 " 26 80 2k 100 23 125 23 150 22 200 22 ■■ U-137 Santa Felicia Dam and Res er voir . The Santa Felicia dam site is located on Piru Creek in the Rancho Temescal land grant, some five miles up- stream from the confluence of Piru Creek and the Santa Clara River, Stream bed elevation at the site is about 870 feet, U.S.G.S, datum. The drainage area of Piru Creek above the Santa Felicia dam site comprises about U22 square miles, and produced an estimated average seasonal runoff during the base period of about 55,800 acre-feet. It was estimated that waste to the ocean of water originating above the dam site would have averaged about 37*600 acre-feet per season during the base period with the present pattern of land use and water supply development. Consideration was given to the construction of a dam and reservoir at the Santa Felicia site for storage of flood waters in Piru Creek, and utilization of the waters so conserved in the Oxnard Forebay, Oxnard Plain^ and Pleasant Valley Subunits of the Santa Clara River Hydrologic Unit. The Santa Felicia dam site and reservoir area were surveyed in 1951 by Fair child Aerial Surveys, Inc., using photogrammetric methods, for the Ventura County Flood Control District, Zone 2, The dam site was mapped up to an eleva- tion of 1,300 feet, at a scale of one inch equals 100 feet, with a 5-foot contour interval. The reservoir area was mapped up to an elevation of 1,250 feet, at a scale of one-inch equals U00 feet, with a contour interval of 10 feet. Storage capacities of Santa Felicia Reservoir at various stages of water surface elevation, derived from the foregoing reservoir area map, are given in Table 98* fc-138 TABLE 98 AREAS AND CAPACITIES OF SANTA FELICIA RESERVOIR Water surface Depth of water > elevation : Water surface Storage capacity, at dam, in feet : • U.S.G.S. datum, in feet : area, in acres : in acre-feet 870 10 880 11 60 20 890 47 350 30 900 65 860 40 910 110 1,730 50 920 150 3,050 60 930 210 4,870 70 940 270 7,270 80 950 390 10,600 90 960 500 15,100 100 970 580 20,400 110 980 690 26,800 120 990 750 34,000 130 1,000 810 41,800 140 1,010 880 50,300 150 1,020 960 59,500 160 1,030 1,030 69,400 165 1,035 1,070 74,600 170 1,040 1,100 80,100 180 1,050 1,190 91,500 187 1,057 1,280 100,000 190 1,060 1,320 104,000 200 1,070 1,420 117,800 210 1,080 1,510 132,. ' r 00 220 1,090 1,600 148,000 230 1,100 1,710 164, 500 240 1,110 1,810 182,100 250 1,120 1,940 200,900 260 1,130 2,070 220,900 270 1,140 2,210 242,300 280 1,150 2,330 265,000 290 1,160 2,460 289,000 300 1,170 2,590 314,300 310 1,180 2,730 340,900 320 1,190 2,870 368,900 330 1,200 3,010 398,300 340 1,210 3,160 429,200 350 1,220 3,300 461,500 360 1,230 3,460 495,300 370 1,240 3,620 530,700 380 1,250 3,730 567,400 4-139 Based upon preliminary geological reconnaissance, the Santa Felicia dam site appears to be suitable for a moderately high earthen dam. Dr. Charles P. Berkey reported on the geology of the Santa Felicia dam site in 1947. A . rogram o] foundation and borrow area exploration at this site, including soil testing, was conducted by the United Water Conservation District in 1952, under the direction o: M.F. Thiel. Except as noted, the geology hereinafter described is based upon pre- liminary geological reconnaissance conducted by the Division of Water Resources in 1951. The axis of the proposed Santa Felicia Dam is located on the southwester ly or downstream limb of an anticline in Modelo sandstones, silt stone, and shales of Miocene age. The strike is across the canyon, more or less east to west, and dip at the axis of the dam is about 40 to 50 degrees downstream. Several of the sandstone members, being more resistant to erosion, stand out prominently and help to create a slight constriction in an otherwise uniformly wide valley. The sand- stone and shales are well bedded, and generally the shale beds are much thinner an more broken. Acid tests reveal very little calcareous cement in the sandstones at the dam axis. The anticlinal structure is very pronounced. The northward dipping limb is about 0.25 mile upstream from the dam site, with a crushed zone near the axis of the fold where it apparently snapped. A large number of producing oil wells have been drilled on this structure in the vicinity of the dam site. Beds are moderately well jointed but should not be expected to leak excessively. The nose of the ridge forming the right abutment is not very thick. Both abutments are relatively steep, with slopes on the order of 1.5:1, though not entirely uniform. However, above about 200 feet from stream bed the right abutment flattens out thus providing a good location for the spillway. Terrace deposits of silty, clayey, and gravelly sands, on the order of 40 feet deep, are found on the ridge in the proposed spillway area, both up and down stream from the axis of the dam. However, one hole drilled in this area by United Water Conservation District indicated a depth of terrace material of about 66 feet. 4-140 Under the program of foundation and borrow area exploration conducted >y United Hater Conservation District in 1952, 36 holes were drilled, amounting ;o about 2,000 lineal feet of overburden drilling and about 1,300 lineal feet of *ock core drilling. Overburden in the stream bed was found to be composed of t mixture of sand, gravel, cobbles, and boulders, while on the abutments and spillway site it was composed of gravel, sand, silt, and clay. Overburden in ,he stream bed was a maximum of 85 feet in depth, and in the spillway area the tepth of overburden varied from to 66 feet. Rock cores taken showed the dam ;ite to be underlain by thick beds of moderately soft massive sandstone and ,hick beds of soft to hard shale, water pressure testing of most of the holes [rilled in the stream bed indicated that little or no grouting in the bedrock ould be required, and led to the assumption that the bedrock will be practically vater tight. It was further assumed that in all probability the reservoir ivill Jso be water tight, due to the tightness of the bedrock and the general •.mpervious nature of the soil overlying the bedrock except in the stream bed. Records of runoff at the Santa Felicia dam site are not available, [owever, runoff at the site was estimated as equal to 97.5 per cent of the teasured runoff at the U.S.G.S. stream gaging station on Piru Creek near Piru. he estimates were based on the ratio of respective watershed areas above the iam site and gaging station. The estimated monthly runoff of Piru Creek at the anta Felicia dam site during the base period is presented in Table 99. U-iUi •a •p o E-« -P P d) CO o o o o cn H -J- cn O m CN O o o o o o -4 to vo fc- cn OOOOO CN I s - vO vO m tr\sO 4C0 O ■4 en O Cn to C>- mc- CO 1*1 •> », •» X »\ O H o cn en cn en o cn cn cn H * n *\ «v «\ rH O-O m c^- cnCN •> CN •> UN in Q O O O 40N0 H O OJ r-i OOOOO OOOOO O OJ tO U-NvO cnH O UN H cn E 3 3 A 1 0000 -4- m vo H CMCM OOOQ OJCMHO cn cn cn rH OOOOO O- -4 Oj O O CA^O CN -4 OOOOO ocv tnto CV H mo CN -» QQ O O O cn H OOO rH UP, tO m H o SO o -4 O o H en CN CD O Q o o vO -4-C * O -4MD en H CM OOOOO OC^OfflOj »t «v «Y a\ »s vOHH4H OOOOO sO to m -4 h OOOOO to : C- -4- -4 " CO H c^ cn cn O to in en en cn o m CN o\ ON I P9 o CD CD «H I CD U o 03 C H P s CD OOOO -4 to mo to cno •* «t «\ «\ o o m c\i H OOOO vONH CN CN o 3" •\ •* ^ H H C"- CN CN CO OOOO m o h o en -4 to *v •", *\ #\ cn o cnt>- cn cn OOOO vO en en -4- CN H F- O •> r\ r\ rv en H -4 cn OOOOO -4 en o in o I s - in en O CN mo- O -4 CN 8 OOOOO mo in cn -4 c- o cn o^ vO 9\ 9\ *\ •» *\ vO en en -4 >n o en -4 O O O Q O O in to -4 O OJOC — 4 o r\ #\ rv »\ «\ -4 CN tO vO to in H CN OOOOO CN O O CN O CN C- r- O- -4 •% «\ •* *\ r\ O -4 O en CN cn OOOOO -4 -4 r-i l>- tO CO rH rH OOOOO in vo vO vO en w c— cn o o *v »\ «\ »\ »\ in rH H r-i r-\ § OOOO cn O rH -vo cn o *N *\ *\ enH o OOOOO in -4 cn en cv o m o in -4- lAvO in cn OOOOO o vo in cn o CO H t> l> tO a in H > o OOOO to <* cno rH CN O to OOOOO in H en in in cn o so o o * »\ CN -4 OOOOO cn oso en en O in -4 H r-\ H IT\ o ■p o o CI o CO 05 CD CO OOOO v£> C- in o C^- rH O O £>- tO OO cn encn -4 I I I I vO c^- to o cn en en cn OOOO r-i r-i H r-\ OOOOO c*- o £> en cn cn o -4 o- en in 3333-4 I I I I L OHCN)cn4 -4 0 feet. The first 60 feet of tunnel would be plugged with concrete, encasing the outlet pipe. A sub- merged concrete intake structure would be located immediately upstream from the tunnel portal. This structure would consist of a chamber, wherein would be located hydraulic and manual controls for a high pressure slide gate, wMch would regulate discharge through the outlet pipe. The intake for the outlet conduit would be located about 2$ feet above the floor of the tunnel. The outlet conduit would consist of a 72-inch diameter steel pipe, supported by ring girders resting on the floor of the tunnel. The conduit would terminate at a control house located at the downstream portal of the tunnel, wherein releases would be further regulated by a 60-inch diameter needle valve. Access to the pipe and intake structure would be maintained through the diversion tunnel. For the dam with height of lUO feet, an intake structure similar to those for the two larger dams was planned. However, the outlet conduit would follow an alignment along the contour of the bedrock on the left abutment. The conduit would be constructed of reinforced concrete, horseshoe in section, and U-UU6 ),$ feet in diameter, and would be placed in a trench excavated to sound rock. I 60-inch diameter steel outlet pipe, supported on ring girders, would be placed /dthin this concrete conduit. The outlet pipe would terminate at the downstream toe of the dam in a control house© Further regulation of reservoir releases would be obtained by installing a 3>U-inch diameter needle valve in the pipe line. Access to the pipe and intake structure would be maintained through the outlet conduit. Based upon field examination, it was estimated that, depending upon the height of dam to be constructed, from 1,030 to 1,H90 acres of light brush and some trees would have to be removed from the reservoir area. The cost of acquisition of private lands, and improvements on private and public lands was estimated by the Ventura County Flood Control District in 195>2 to be about §Ui6,650. In 1952, the United Water Conservation District estimated the cost of necessary road relocation to be about $1^0,000, and oil well damages to be about ^200,000. Presented in Table 101 are pertinent data with respect to the general features of the three sizes of dams and reservoirs considered at the Santa Felicia site, as designed for cost estimating purposes. For illustrative pur- poses, a plan, profile, and section for the dam creating a reservoir with storage capacity of 100,000 acre-feet are shown on Plate 3U, entitled "Santa Felicia Dam on Piru Creek". k*m TABLE 101 GENERAL FEATURES OF THREE SIZES OF DAM AND RESERVOIR AT THE SANTA FELICIA SITE ON PIRU CREEK Earthfill Dam Crest elevation, in feet, U.S.G.S. datum - . 1,030 1,055 1,077 Crest length, in feet 1,0U0 1,160 l,2ijD Crest width, in feet 30 30 30 Height, spillway lip above stream bed, in feet mo 165 187 Side slopes, upstream and downstream 2.5:1 3:1 3:1 Freeboard, above spillway lip, in feet 20 20 20 Elevation of stream bed, in feet, U.S.G.S. datum 870 870 870 Volume of fill, in cubic yards 3,037,900 U,527,000 5,U28,000 Reservoir Surface area at • spillway lip, in acres 88U 1,066 1,280 Gross storage capacity at spillway lip, in acre-feet 50,000 75,000 100,000 Type of spillway Ogee weir Ogee weir Ogee weir and concrete and concrete and concrete lined chute lined chute lined chute Spillway discharge «-: capacity, in • second-feet 103,0^0 103,000 103,000 Type of outlet 60-inch diameter 72-inch diameter 72-inch diameter steel pipe, in steel pipe, steel pipe, reinforced through through diversion concrete conduit diversion tunnel ■ beneath dam tunnel U-1U8 Presented in Table 102 is a summary comparison of capital and annual costs of the three considered sizes of dam and reservoir at the Santa Felicia site. Also presented in Table 102 are estimated unit costs of storage capacity and net safe yield of water that would be developed by construction of the three sizes of reservoir. Yields referred to are those that would result under the uniform release method of reservoir operation with releases for main- tenance of historic ground water levels. Certain of the relationships presented in Table 102 are depicted graphically on Plates 35 , 36, and 37. Detailed estimates of cost for the three sizes of dam and reservoir at the Santa Felicia site are included in Appendix C. TABLE 102 SUMMARY OF ESTIMATED COSTS OF DAMS, RESERVOIRS, AND YIELDS OF WATER AT SANTA FELICIA SITE ON PIRU CREEK Reservoir storage ca; Dacity, Item in acre- -feet : 50,000 : 75,000 : 100,000 Capital Costs Dam and reservoir % 7,128,000 % 8,417,000 ft 9,029,000 Cost per acre-foot of storage 343 112 90 Cost per a ere -foot of net safe yield 1,080 765 600 Annual Costs Dam and reservoir 369,000 435,000 469,000 Cost per acre-foot of net safe yield 56 40 31 Cost per acre-foot of incremental net safe yield 15 8 4-149 Conveyance and Distribution of Supplemental Water This section describes the various conveyance and distribution systems that were considered for delivery of locally developed supplemental water to area; of need in Ventura County, and presents preliminary cost estimates thereof. The location and alignment of the systems studied are shown on Plate 42, entitled "Proposed Conveyance and Distribution Systems". In general, preliminary design of the conveyance and distribution systems was made by the use of available U.S.G.S. topographic maps, at a scale of 1:24,000 and with a contour interval of 20 feet, and from information obtained during field reconnaissance of the propose: routes. In most cases, design of the systems was limited to the main laterals extending to strategic points in each of the hydrologic units, and no attempt was made to estimate the cost of connection with individual water users. Except as noted, preliminary estimates of cost acquisition of right of way and relocatio: of existing facilities, when necessary, were made on the basis of field examinati and appraisal during the course of the investigation. Distribution System for Casitas Reservoir . In the preliminary lesign for a distribution system to serve water developed by Casitas Reservoir, it was assumed that sufficient reservoir storage capacity would be constructed to provid new water in an amount equal to the estimated present supplemental water require- ment in the Ventura Hydrologic Unit, of about 4,000 acre-feet per season, plus an allowance to provide for a portion of the probable ultimate supplemental water requirement of about 31>000 acre-feet per season. It was assumed that the initia distribution system from the reservoir would deliver about 13,3°0 acre-feet of water per season, distributed in accordance with the following tabulation: 4-150 Seasonal delivery of water, in acre-feet Upper Ojai 760 Ojai 1,200 Upper Ventura River 3,320 Lower Ventura River 6,920 Rincon 1,160 TOTAL 13,360 The amounts shown in the tabulation may be compared with values for oresent and' probable ultimate supplemental water requirements in the Ventura ■iydrologic Unit presented in Tables 47 and 48. In November, 1951, the Ventura County Flood Control District prepared a report entitled "Distribution of Water Stored in Casitas Reservoir and Matilija Reservoir to Lands and Users in the Year 1975", describing a distribution system for water from Casitas Reservoirs. In accordance with the request of the Board of Supervisors of the Ventura County Flood Control District, this report was reviewed by the Division of Water Resources and the results of the review were submitted to the District on June 30, 1952. The distribution system described herein conforms in general alignment to the plan prepared by the Ventura County Flood Control District, and is based on surveys, appraisals, and designs made by that District. However, certain revisions were made in line capacities and estimates of cost. The locations of Casitas Reservoir and the distribution system therefrom are shown on Plate 42. From the outlet control house at Casitas Dam, the main feeder line of the distribution system would follow Casitas Pass Road generally downstream along the right bank of Coyote Creek, and would connect with the Foster Park intake of the City of Ventura 1 s water system. This feeder line would convey the entire supply from the reservoir for the Upper Ojai, Ojai, and Upper and Lower Ventura River Subunits. It would have a discharge capacity of about 32 second-feet, and would 4-151 be capable of delivering about 2,000 acre-feet per month. This amount represer about 15 per cent of the assumed seasonal supply available from the reservoir, which is somewhat greater than the estimated maximum monthly percentage of seasonal demand for water in the Ventura Hydrologic Unit. By designing the ma: feeder and laterals under this criterion, some additional peaking capacity was obtained. The main-feeder line to Foster Park would be about 14,000 feet in length, and would be constructed of 36-inch diameter centrifugal spun reinforce concrete pipe. From Foster Park, a smaller line would extend northerly a distance oJ about 9,000 feet to the vicinity of Lacrosse, where a wye would be installed. This 27-inch diameter reinforced concrete cylinder pipe would have a capacity c about 14 second-feet, and would deliver about 5,280 acre-feet per season. From the wye near Lacrosse, one branch line would continue northerly about 18,000 lineal feet generally parallel to the Ventura River to State Highv? 150, where another wye would be located. This line would consist of a 24-inch 1 diameter reinforced concrete pipe with a capacity of 10 second- feet, and would deliver a seasonal supply of about 3,750 acre feet. A regulatory reservoir of about 50 acre-foot storage capacity would be located north of Oak View on the line. It was assumed that a pumping plant, required on this line to lift the water about 350 feet, would consist of three pumps installed in series, each wji a 200 horsepower motor. From the wye near Lacrosse, a second line would extend northeasterly along San Antonio Creek, a distance of about 42,800 feet to a regulating reservoir, about 1.8 miles easterly from the town of Ojai at an elevation of 880 feet. This line would consist of a 16-inch diameter reinforced concrete cylinder pipe with capacity of 4.0 second-feet, and would deliver a seasonal supply to the regulating reservoir of about 1,525 acre-feet. It was assumed that two pumping plants would be utilized on this line, each equipped with a 100 horsepower motor and each lifting the water about 310 feet. 4-152 From the wye at State Highway 150, one line would extend westerly across •ie Ventura River about 13,^00 lineal feet to a regulating reservoir of 50 acre- ;)ot storage capacity in the Santa Ana Creek watershed. This lii-inch diameter •jinforced concrete cylinder pipe, with capacity of about 3.5 second-feet, would Oliver a seasonal supply of about 1,315 acre-feet to the regulating reservoir at a elevation of 665 feet. From the vrye at State Highway 150, another conduit would extend about l,lj.00 lineal feet to a point immediately north of Meiners Oaks, where an inter- onnection would be made with the existing pipe line from Matilija Reservoir. This S-inch diameter reinforced concrete cylinder pipe, with capacity of about h.5 scond-feet, would deliver a seasonal supply of about 1,700 acre-feet. It was ssumed that a pumping plant, required on the line to lift the water about 360 I set, would consist of three pumps, each equipped with a 120 horsepower motor. From the aforementioned regulating reservoir easterly of Ojai, a line ould extend northerly to provide an additional interconnection with the existing atilija pipe line. This lateral would consist of about ii,500 lineal feet of 12- nch diameter reinforced concrete cylinder pipe, with a capacity of about 1.2 econd-feet, and would deliver a seasonal supply of about 1+50 acre-feet. From he same regulating reservoir, another conduit would extend easterly about 10,200 ineal feet to serve the Upper Ojai Subunit. This 12-inch diameter reinforced oncrete cylinder pipe, with capacity of about 2.0 second-feet, would deliver a easonal supply of about 760 acre-feet, and would terminate at an elevation of ,312 feet in a small terminal reservoir. It was assumed that a pumping plant, equired in this line to lift the water about 1*50 feet, would consist of two umps connected in series, equipped with 100 horsepower and 50 horsepower motors, espectively. U-153 From the terminus of the existing Matilija pipe line, a new line would extend northeasterly about 9,000 lineal feet to a regulating reservoir of about 40 acre- foot storage capacity at an elevation of 1,300 feet. This 10-inch dia- meter welded steel pipe, with capacity of about 1.2 second-feet, would deliver a seasonal supply of about 450 acre-feet. A pumping plant, required on the line to lift the water about 420 feet, would consist of two pumps installed in series, equipped with 50 horsepower and 25 horsepower motors, respectively. Immediately west of Ojai, an extension from the existing Matilija pipe line would be constructed northerly about 5,000 lineal feet to a regulating reservoir of 40 acre-foot storage capacity at an elevation of 980 feet. This 14-inch diameter reinforced concrete cylinder pipe, with capacity of about 4.4 second-feet, would deliver a seasonal supply of about 1,640 acre-feet. From the Foster Park intake of the City of Ventura, a pipe line would b constructed southerly to Canada Larga and thence northeasterly along Canada Larga This would consist of about 29,200 lineal feet of 6-inch diameter welded steel pipe with capacity of about 0.5 second-feet, and would deliver a seasonal supply of about 175 acre-feet. A pumping plant, required to lift the water about 400 feet to an elevation of 760 feet, would consist of two pumps, installed in series equipped with 10 horsepower and 20 horsepower motors, respectively. Commencing at the outlet control house at Casitas Dam, a pipe line woul extend westerly along the relocated Casitas Pass Road to Casitas Summit, a dis- tance of about 1,300 feet, and thence southwesterly to the ocean at Sea Cliff, a distance of about 21,000 feet. From Sea Cliff, one lateral would extend along the ocean a distance of about 45,000 feet to the Ventura River, and another would extend westerly a distance of about 20,000 feet to the vicinity of the County line near Rincon Point. This system would be constructed of welded steel 4-154 Dipe, with the main conduit and the lateral to the Ventura River having 10-inch iiameters, and the westerly lateral having an 8 inch diameter. The main conduit f tfith capacity of 3.0 second-feet, would deliver a seasonal supply of about 1,160 acre-feet. Capacities of the lateral to the Ventura River and of the westerly lateral would be about 2.0 and 1.0 second-feet, respectively. A pumping plant, required to lift the water about 1,000 feet to an elevation of 1,375 feet at Casitas Summit, would consist of three pumps installed in series, each equipped with a motor of 150 horsepower. The capital cost of the distribution system for Casitas Reservoir was estimated to be about $2,954,000* The annual costs, including interest on and amortization of the capital investment, operation and maintenance, replacement, and electrical energy charges for pumping, were estimated to be about $252,000. Detailed estimates of cost of the distribution system are presented in Appendix C. Casitas-Oxnard Plain Diversion. In view of the fact that net safe yields that would be developed by the considered sizes of Casitas Reservoir substantially exceed present requirements for supplemental water in the Ventura Hydro logic Unit, consideration was given to the diversion of a portion of this excess water supply to the Oxnard Plain Subunit. It was realized that ultimately the entire net safe yield available from Casitas Reservoir site would be required in the Ventura Hydrologic Unit. However, for an interim period, possibly as long as 20 years, a surplus of water would exist. For cost estimating purposes, it was assumed that for a 20-year period subsequent to the reservoir construction it would be possible to divert an average seasonal supply of 10,000 acre-feet of water from Casitas Reservoir to the Oxnard Plain Subunit for use therein. It was assumed that the Casitas-Oxnard Plain Diversion Conduit would extend from the outlet control house at Casitas Dam in a pipe line, independent 4-155 a of the one previously described for the distribution system for the Ventura Hydrologic Unit, to a terminus in a regulating reservoir north of the City of Oxnard. From the dam, the line would parallel Coyote Creek downstream, and would follow the Casitas Pass Road to Foster Park, crossing the Ventura River near the existing highway road bridge. The crossing would be in a conduit buri to a depth of 10 feet beneath the stream bed and encased in concrete. The line would then turn southerly and generally parallel the Southern Pacific Railroad tracks to the Ventura County Fair Grounds. At the fair grounds it would turn southeasterly, continue generally parallel to the Southern Pacific Railroad tracks to the Ventura Municipal Golf Course, about 3,000 feet southwest of the community of Montalvo. The line would cross the Santa Clara River at a point about one-half mile downstream from the U.S. Highway 101 bridge. The crossing would be effected in a buried conduit, encased in concrete, with 20 feet of cover. From the Santa Clara River, the line would extend to the aforementioned regulating reservoir near the intersection of Gonzales and Rose Roads, about 1.3 miles southeast of the community of El Rio. This reservoir, designated the Oxnard Reservoir, would have a storage capacity of 100 acre-feet, and a normal water surface elevation of about 85 feet. The Casitas-Oxnard Plain Diversion Conduit would comprise a total length of about 96,300 lineal feet, consisting of about 49,000 lineal feet of 3 inch diameter, and about 47,300 lineal feet of 27-inch diameter lock joint con- crete cylinder pipe. The pipe line would have a capacity of about 25 second- feet, and would deliver a seasonal supply of about 10,000 acre-feet. It would be capable of delivering about 15 per cent of the total seasonal supply in the month of maximum demand. The capital cost of the Casitas-Oxnard Plain Diversion Conduit was estimated to be about $1,671,000. Based upon an assumed 20-year life and a 4 per cent interest rate, annual costs were estimated to be about $127,000, 4-156 including interest on and amortization of the capital investment, and operation and maintenance. On this basis, that portion of the average annual unit cost of water delivered through the conduit to the Oxnard Plain Subunit attributable to the costs of the conduit was estimated to be about $L2. 70 per acre-foot. The proposed alignment of the Casitas-Oxnard Plain diversion is shown on Plate i|2. Detailed estimates of cost of the diversion conduit are presented in Appendix C. Santa Clara River Conduit . It has been demonstrated that to realize maximum benefit from reservoirs constructed on tributaries of the Santa Clara River, the conserved waters must be conveyed to areas of need in the Oxnard Plain and Pleasant Valley Subunit s in a conduit. Consideration was given, therefore, to the construction of a pipe line from Piru Creek down the Santa Clara River Valley to a terminus in the aforementioned Oxnard Reservoir near El Rio. The general alignment of this Santa Clara River Conduit, as designed for cost estimating purposes, is shown on Plate 1|2. For illustrative purposes, a conduit that would extend from the proposed Devil Canyon Dam is described herein. If dams and reservoirs were to be constructed on Sespe or Santa Paula Creeks, feeder lines would be required to connect with the main conduit. Such a feeder line from Sespe Creek is contemplated for the described conduit. Provision xvould be made for release from the conduit to meet the requirements of prior water rights, as necessary. From the outlet works at Devil Canyon Dam to a point about 0.3 mile west of the community of Sespe Village, where a feeder line from Sespe Creek would connect with the main line, the Santa Clara River Conduit would consist of about 63,600 lineal feet of 36-inch diameter, and 26,600 lineal feet of li2-inch diameter reinforced concrete cylinder pipe. The line would extend southerly from Devil Canyon Dam along the left bank of Piru Creek for about 2U,000 feet. At this point, ii-157 it would cross the creek and thence, passing though the town of Piru, would generally follow the alignment of State Highway 126 to the town of Fillmore and to Sespe Village. The conduit would cross Sespe Creek southwest of Fillmore. At all major stream crossings, the pipe line would be encased in reinforced concrete and buried under 20 feet of cover. It was assumed that the foregoing pipe line, with a capacity of 65 second-feet, would deliver a seasonal supply at its juncture with the Sespe Feeder of about 22,000 acre-feet. This capacity was based upon an assumed maximum monthly demand of about 12 per cent of the seasonal total, with an additional allowance for weekly demand peaks. It was assumed that water released from reservoirs to be constructed on Sespe Creek, other than the Fillmore Reservoir, would be diverted into the Sespe Feeder by a concrete diversion weir of ogee section founded on bedrock at a point about 800 feet upstream from the U.S.G.S. stream gaging station on Sespe Creek near Fillmore. The weir would be 6 feet in height above stream b< and would have a crest length of about 200 feet. An intake structure, sand trap, and sluiceways, similar to those described for the Ventura River-Casitas Diversic would be provided. The diverted water would be conveyed through a 36-inch diameter reinforced concrete cylinder pipe, about 28,800 feet in length, to the juncture with the Santa Clara River Conduit. It was assumed that the feeder lin< would deliver seasonal supply of about 18,000 acre-feet. It would have a capacil of 55 second-feet, based upon the previously described criteria utilized in design of the main conduit from Devil Canyon Dam. From the point of connection with the Sespe Feeder the Santa Clara River Conduit would generally follow the alignment of State Highway 126 to the City of Santa Paula, and thence, following a generally southwesterly route along the right bank of the Santa Clara River, would cross the river near the existing diversion works of the Saticoy spreading grounds. Near these diversion 4-158 ■works, a bifurcation structure in the conduit would permit releases to the spreading grounds. Such releases would be controlled by two U8-inch diameter gate valves. The conduit would then extend generally along the alignment of Ditch Road to Oxnard Reservoir. From its juncture with the Sespe Feeder, the Santa Clara River Conduit would consist of about 67,5>00 lineal feet of 5U-inch diameter, 15>>000 lineal feet of lj8-inch diameter, and 10,000 lineal feet of 1^2- inch diameter reinforced concrete cylinder pipe. The conduit would have a capacity of 120 second-feet, and would deliver a seasonal supply to Oxnard Reservoir of 1^0,000 acre'-feet. Presented in the following tabulation is a summary of estimated capital and annual costs of the Santa Clara Conduit. Detailed estimates of costs are presented in Appendix C. Estimated Costs Portion of Santa Clara River Conduit Capital Annual Devil Canyon Dam to Sespe Creek $2,012,000 $107,000 Sespe Creek to Oxnard Reservoir 2,907,000 15U,000 Sespe Feeder 8Ui,000 U7,000 T0TA1S 05,763,000 $308,000 Oxnard Plain-Pleasant Valley Distribution System . As discussed in a later section of this chapter, it was concluded that ground water overdraft in Oxnard Plain and Pleasant Valley Basins, resulting in part from the lack of aquifer transmissibility, will necessitate the construction of a surface dis- tribution system to serve supplemental water to certain lands in the Oxnard Plain and Pleasant Valley Subunits now supplied by pumping from ground water. There follows a description and preliminary cost estimates for a possible distribution system to serve supplemental water to about 21,600 net acres of agricultural land in the Oxnard Plain and Pleasant Valley Subunits, together with the Cities of hrl$9 Oxnard and Port Hueneme, and the United States Navy Advance Base at Port Hueneme. The system would deliver a maximum seasonal supply during drought periods of abou 45,000 acre-feet. The location of the lands to be served and the general align- ment of the major distributaries are shown on Plate 42. Choice of a distribution system capacity of 45,000 acre-feet per season was based on the following consideration. The total present requirement for supplemental water in the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Sub- units was estimated to be about 74,000 acre-feet per season during drought period; However, in arriving at this estimate, direct evaluation of all items of water supply to these subunits could not be made. It is entirely possible that there it a substantial contribution to the confined aquifers of the Oxnard Plain and Pleasant Valley Basins from percolation of rainfall and of the unconsumed portion ; of applied water. If this should prove to be the case, the estimates of supple- mental water requirement should be reduced accordingly. For this reason, and in light of the determined magnitude of local supplemental water supplies that appeal to be feasible of development, the initial works to distribute supplemental water in the Oxnard Plain and Pleasant Valley Subunits were designed with the capacity indicated. In design of the distribution system, it was assumed that an irrigating head of one second- foot for every 80 acres of agricultural land would be required, From analysis of agricultural power consumption data, and the results of studies of water use practice conducted by the Division of Water Resources, it was estimat ed that during the month of maximum xvater demar^i about 40 per cent of the agri- cultural lands served would require water service at a given time. Thus, the tota required capacity of the distribution system was estimated to be one second-foot for each 200 acres of service area, or about 120 second-feet in a]2,including a small additional allowance for peaking capacity. Lands that would be served 4-160 y the system, as designed, are largely those that were underlain by a landward " radient in the piezometric surface in the Qxnard and Fox Canyon aquifers during he drought period. The distribution system to serve agricultural lands would commence at ihe Qxnard Reservoir, which is the terminus for conduits considered for supplying upplemental water to the Qxnard Plain and Pleasant Valley Subunits. It was issumed that this reservoir would have a storage capacity of about 100 acre-feet, •;jith inside dimensions of 450 by 450 feet and a normal depth of water of 20 feet. -jxcavation for the reservoir would extend to a depth of 8 feet below ground sur- i^ace. The excavated material would be used in a rolled earthfill embankment, •forming the sides of the reservoir. This embankment would be about 14 feet in bight above ground surface, with 1.551 side slopes and a 20-foot top width, and 'i: feet of freeboard would be provided above the normal water surface. Seepage tj'rom the reservoir would be prevented by a buried asphaltic concrete membrane. Reservoir releases would be effected by a 60-inch diameter reinforced concrete Cylinder pipe placed through the embankment, regulated by a slide gate at the intake of the pipe. Additional control would be obtained by a gate valve at the lutlet end of the pipe. From Oxnard Reservoir, two major laterals were considered. One line rculd extend westerly from the reservoir along Gonzales Road to Ventura Road, \rhere a wye would be placed in the line. From this point, one branch would continue westerly to serve the area along the Gonzales Road, and the other branch rould extend in a generally southerly direction to serve the area w*st of the 3ity of Oxnard. The second major lateral would extend southerly from Oxnard teservoir and east of the City of Oxnard, and would serve the area east of the Cities of Oxnard and Port Kueneme and generally west of Revolai Slough. An idditional regulating reservoir to provide peaking capacity was considered to be 4-161 necessary on this lateral, at the intersection of Pleasant Valley and Rice Roads. This reservoir would have a storage capacity of about 50 acre-feet, and would be similar in construction to Oxnard Reservoir. The major laterals and branches of the irrigation distribution system would be constructed generally of centrifugally spun reinforced concrete pipe, varying in diameter from 12- inches to 54-inches, and totalling 174>500 feet in length. The lines were located so that ties to existing irrigation systems served by wells would not exceed about one-half mile in length. It was estimate that about 190 such ties would have to be made to the distribution system. In order to provide supplemental water requiring a minimum of treatmerr to the Cities of Oxnard and Fort Hueneme and to the United States Navy Advance Base at Port Hueneme, it was assumed that well fields would be constructed in Oxnard Forebay Basin, and that a conduit, independent of the agricultural distri bution system, would be constructed to serve these entities. Supplemental water for this purpose could be discharged from the Santa Clara River Conduit to the Saticoy spreading grounds. Thus, Oxnard Forebay Basin would function as a slow aand filter for the supplemental municipal supplies. The well fields would be located northeast of the community of El Rio, one at a site immediately west of Vineyard Avenue, and one at a site between Vineyard Avenue and Ditch Road. Each field would comprise about 20 acres of land, and would contain 8 wells. It was assumed that each well would be 18 inches in diameter and 250 feet deep, with pump bowls set at a depth of about 175 feet. The gravel packed and cased wells would be placed in two rows of four wells each, with a distance of 400 feet between wells. Each well would be equipped with a pump driven by a 75 horsepower motor. It was estimated that, with the lowest ground water levels expected to occur in this vicinity, each well would produce about 1,400 gallons of water per minute. With all wells in operation, the maximum discharge from the two fields would be about 50 acre- 4-162 feet. Wells in the two fields would connect to a common pipe line, which would extend southerly along Ditch Road to the vicinity of Oxnard Reservoir, where, a connection would be made to the reservoir so that emergency interim supplies for agricultural use could be obtained from the well fields. From Oxnard Reservoir, the pipe line would continue southerly on Rose Road for a distance of about 6,500 feet, where a lateral would extend westerly to connect with the existing distribution system of the City of Oxnard. The main line would continue southerly, thence westerly to the United States Navy Advance Base, and thence southerly to Port Hueneme. A lateral extension would also be provided to serve the American Crystal Sugar Company's factory at Oxnard. Although not included as an initial feature of the considered municipal distribution system, a lateral could be constructed to meet presently relatively minor water requirements of the naval installation at Point Mugu. The over-all length of the municipal conduit, from the well field near Ditch Road to its terminus at Port Hueneme, would be about 45,000 feet. It was assumed that at the present time the municipal conduit would serve about 10,000 acre-feet of water per season. From the well fields to the take-off of the City of Oxnard, the pipe line would have a capacity of 40 second- feet. From this point to the take-off for the American Crystal Sugar Company, its capacity would be 30 second-feet. From this point to a take-off for the Naval Advance Base, capacity of the pipe line would be 15 second-feet. The final portion of pipe line to Port Hueneme would have a capacity of 10 second-feet. Presented in the following tabulation is a summary of estimated capital and annual costs of the proposed distribution system for the Oxnard Plain and Pleasant Valley Subunits. Detailed estimates of cost are presented in Appendix C, 4-163 Estimated costs Item Capital , Annual Average annual unit • cost of supplemental water attributable to cost of distribution system, per acre-foot Agricultural system, includ- ing regulating reservoirs $3,038,000 $169,000 $4.80 Municipal system, including well fields 1,318,000 94,000 9.40 Piru-Las Posas Diversion. As described heretofore, consideration was given to the operation of a Devil Canyon Reservoir, constructed to a storage capacity of 150,000 acre-feet, for the joint benefit of the Santa Clara River ar. Calleguas-Conejo Hydrologic Units. In this connection, estimates of cost were prepared for seven capacities of the Piru-Las Posas Diversion Conduit to convey water from Devil Canyon Reservoir to the Calleguas-Conejo Hydrologic Unit. As an alternative to Devil Canyon Reservoir as a source of water supply, studies were also made of a conduit from Blue Point Reservoir to serve the Calleguas- Conejo Hydrologic Unit. For illustrative purposes, only those studies relating to utilization of Devil Canyon Reservoir for the purpose are described herein. From reconnaissance type estimates of cost of several possible routes, it was concluded that the most economical conduit alignment would extend from th outlet works of the dam down Piru Creek to the town of Piru, and thence would follow the right bank of the Santa Clara River to a point immediately upstream from the State Fish Hatchery. At this point the conduit would cross the Santa Clara River, and then extend up Shiells Canyon to the northerly portal of aixmnal through Oak Ridge. This tunnel would extend southerly and terminate in Happy Canyo in the East Las Posas Subunit. Alternative conduits having capacities of 40, 4-164 60, 80, 100, 125, 150, and 200 second-feet were studied. For illustrative purposes, features of the Piru-Las Posas Diversion Conduit with capacity of 80 second-feet are described herein. Water for the conduit would be discharged through. the; outlet works at Devil Canyon Dam at an elevation of about 1,090 feet. From Devil Canyon Dam to the northerly portal of the Happy Camp Canyon Tunnel, the conduit would consist of about 54,800 lineal feet of 60-inch diameter, and 12,700 lineal feet of 54-inch diameter lock joint concrete cylinder pipe. At the required crossings of Piru Creek and the Santa Clara River, the conduit would be buried to a depth of 20 feet and encased in concrete. Slope of the hydraulic gradient in the pipe line would be 1.2 feet per thousand feet. The Happy Camp Canyon Tunnel would be con- crete line, of horseshoe section, 7 feet in diameter, and about 13,500 feet in length. Invert elevation of the northerly portal would be about 1,005 feet, and about 990 feet at the southerly portal. Water would flow by gravity in the tunnel at a normal depth of 5.7 feet, with a velocity of 5.2 feet per second. Presented in Table 103 are estimated capital and annual costs of the Piru-Las Posas Diversion Conduit for the seven alternative conduit sizes studied. Also shown are estimates of the proportionate average annual costs of a Devil Canyon Reservoir, with 150,000 acre-feet of storage capacity operated for joint benefit of the Santa Clara River and Calleguas-Conejo Hydrologic Units, deemed chargeable to the latter hydrologic unit. These costs were proportioned on the basis of the amounts of net safe yield made available to each hydrologic unit. Table 103 also shows estimated unit costs of net safe yield made available to the Calleguas-Conejo Hydrologic Unit, on the same basis. 4-165 s 1 H (0 ; 1) cu gCtt 1 CO «H CO H ?-l O (0 Ph C CO -p (0 o o iH H cd cO a -P O cO 0) cO (h rH C CO o ^ > £<*>>•* < : Proportio : cost o : Devil Can : Reservo c O -P •H -H CO 3 (h T3 CO c ► O •H O Q H«h.P cO O -H -P 3 ■H4JT) a to g cO o o o o o 1 o •» Ti c fc M-5-p H cd-rl O CO -H +3 43 c d o :r> CO O >»H $-. CO O «H CO •H CO H 1 O 1 cO © > (0 ilab guas logi acre r se H U C D. CO fc >a d 3 «H cO >» o a; tH C -P O C! -H CO 0) W) O CO (U >a-H « 'O O •H a-H G O cO T3 O CO Q O O CO 3 3» 8 o o -4 H •» 3J= CA •s H SO ir\ 3 vr\ ur\ CM cm v> en -4 O O en cm en en O O O •> t> sO cm NO 3 3 3 o o o vO o vO o o H O en O o ->* CO en 8 to CO § o 5 CO o CO o o o m -4 o o o H O -4- CO s 3- 3 o o o o o o o o 8 8 o o o CO CM -4- t> CO CM •V ■1 •> •\ •\ •\ •> vO vO o CO CM o ir\ CM CO -4 o- CM tr\ CM c- o- CO co o o O O o O o o 8 O O o O o c O O m CM CO o t>- vO »\ *» •* ■1 •> •s •» en -4 o -o •\ O o O o O O o O o O o H CO o ^4 U> •\ •\ •V •» •X o o H CM en CM CM CM CM CM o O O 8 u% O O -4 vO CO CM ir\ O H H H CM 4-166 Planned Operation of Ground i/ater Storage As described in Chapter II, certain of the major ground water basins in Ventura County are not presently utilized to the maximum practicable extent. Consideration was given to enhancement of presently developed yields of ground waters from these basins through their planned operation. Such operation would involve either the modification of present patterns of pumping or the increased use of water from the basins, or both, depending upon the individual character- istics of the basin under consideration. Development of increased yield of water through planned operation of ground water storage was determined to be the least expensive of all investigated sources of supplemental water available to Ventura County. In certain ground water basins of the County, such planned operation would result in the development of substantial quantities of new water with relatively small capital expenditures, in comparison with the costs of surface storage necessary to develop comparable amounts of supplemental water. In addition, as compared with water in surface storage, evaporation losses would be negligible, and with lowering of ground water levels through increased use of the basins, nonbeneficial consumptive use of water by native vegetation would be reduced or eliminated. From a practical standpoint, hoxrever, there are legal considerations which must be recognized in any plan for operation of ground water storage. Under the law, an overlying user in a ground water basin has a paramount right, correla- tive with all other overlying users, to the reasonable and beneficial use of ground water in the basin. He is, therefore, entitled to the protection of the courts against any substantial infringement of his correlative right to the ground water which he reasonably and beneficially requires, and against any use of the ground water by an appropriator which would cause an impairment to his right. That type of planned operation of ground water storage which would involve increased use of water from the basin, and possibly that type which would 4-167 modify the pumping pattern, would result in lowering of ground water levels. The attendant inconvenience or extra expense to an overlying user would not necessar- ily prevent such planned operation, providing it could be shown that such inconvenience or added expense were not unreasonable. The question of what constitutes unreasonable inconvenience or expense is not subject to exact determination. However, it may be assumed that greater energy charges resulting from increased pumping lifts would not be considered an unreasonable expense or inconvenience, as long as presently installed pumping equipment of the overlying user could continue to be utilized. A material lowering of ground water levels that would necessitate deepening of wells and replacement of pumping equipment probably would be considered unreasonable. In any actual case, these matters would have to be determined by negotiated agree- ment or by the courts. In the studies described herein, it was not possible with data at hand to evaluate these factors. It is believed, however, that the success of planned operation of a given ground water basin would be contin- gent upon the voluntary negotiation of a mutually satisfactory agreement between the overlying ground water users and the operating agency. Described in this section are studies relating to planned operation of ground water storage in Ventura County considered from the standpoints of both independent operation of the ground water basins and their operation in conjunction with existing or proposed surface storage developments. O.iai Basin . The total ground water storage capacity of Ojai Basin was estimated to be of the order of 70,000 acre-feet, and the maximum ground water storage depletion of record therein, occurring in the fall of 1951 > was estimated to have been about 28,000 acre-feet. In the latter years of the drought period fr 19hh-h$ through 1950-51* wells near the margin of Ojai Basin were dry. Based in 4-168 part on this fact, it was estimated that the usable storage capacity in the basin, with the present pattern of pumping, is about 10,900 acre-feet. Thus, with the present pattern of pumping only about 15 per cent of the total avail- able ground water storage capacity is usable, and it appears that utility of the basin could be enhanced by serving the marginal areas from water supplies pumped near the center of the basin. Although storage depletion in Ojai Basin in the fall of 1951 was about 28,000 acre-feet and there is an estimated mean seasonal net draft on the ground water of approximately 3,500 acre-feet, the basin was essentially filled in 1952. This filling was undoubtedly accelerated by percolation and use of water diverted from Matilija Reservoir during 1952, but it is probable that during a wet period and with the present net draft the basin would fill naturally. Whether or not such filling would occur with a substantially greater net draft on the basin could not be determined. It is probable however, that perennial lowering of ground water levels would not result if the pumping pattern were shifted from the margins to the center of the basin, and if the present mean seasonal net draft were not exceeded. It is indicated that, were such a plan to be put into effect, the present ground water overdraft on Ojai Basin estimated to be about 2,000 acre-feet per season, would be eliminated. Under the plan described in the preceding paragraph, it was estimated that about 1,200 net acres of land around the periphery of Ojai Basin would require water from wells located in the central portion. It is probable that in most cases the large capital expense involved in delivering the pumped ground water, in addition to the cost of drilling new wells, would prohibit execution of the plan by individual users. Furthermore, the success of such a plan would be contingent upon the willingness of ground water users overlying the center of the basin to permit drilling and subsequent operation of wells for the purpose of delivering water to the marginal areas. 4-169 Although not planned operation of ground water storage in the sense of the preceding discussion, an alternative solution to the problem of ground water overdraft in Ojai Basin lies in the spreading and percolation of water from Matilija Reservoir in the basin or its use in the Ojai Subunit. As described previously, such spreading was done by the Ventura County Flood Control District during 1952. During wet periods, Ojai Basin probably would fill naturally with the present pattern of land use and water supply development, and spreading or use of water from Matilija Reservoir would not in itself increase the yield of the basin. However, it would accelerate recovery of ground water levels therein During drought periods, when ground water levels in Ojai Basin would be drawn down below safe elevations, the net safe yield on Matilija Reservoir, in the estimated amount of about 1,400 acre-feet per season, could be delivered to and spread in Ojai Basin or used in the subunit. By this means, the present ground water overdraft would be substantially reduced. With construction of a reservoir at the Casitas site on Coyote Creek, and augmentation of inflow to that reservoir by diversion of flood waters from the Ventura River, it would be possible for certain entities, including the City of Ventura, which have established rights to waters of Matilija Creek originating above the reservoir, to forego those rights in exchange for rights in water served from Casitas Reservoir. If, through negotiation, such a plan could be effected, sufficient additional water could be developed at Matilija Reservoir and delivered to the Ojai Subunit to eliminate present ground water overdraft and to provide some water for the needs of future development . Piru, Fillmore, and Santa Paula B as ins. It was stated in Chapter II that the utility of Piru, Fillmore, and Santa Paula Basins is believed to be limited by factors of economic pumping lift and mean seasonal recharge, rather than by storage capacity or configuration of the basins, and that the basins are not presently utilized to the maximum practicable extent. Consideration was 4-170 *iven to increased use of these basins for developing supplemental water to alleviate ground water overdraft conditions in the Oxnard Forebay, Oxnard Plain, md Pleasant Valley Basins. Such increased use would involve the construction of Arell fields in the upper basins and the conveyance of water extracted therefrom to areas of need in the lower subunits. Such planned operation would result in a greater lowering of ground water levels in Piru, Fillmore, and Santa Paula Basins than would occur with the present patterns of land use and water supply development. The lowered ground water levels, in turn, would provide greater underground storage space for the capture of waters that would otherwise waste to the ocean during wet periods. Consideration was also given to the operation of potential surface storage reservoirs on tributaries of the Santa Clara River under the uniform release method, without release of water stored therein to maintain ground water ;in the three basins at historic levels. Such a method of surface reservoir operation would lower ground water levels in Piru, Fillmore, and Santa Paula Basins, create greater underground storage space for the capture of otherwise waste of flood flows, and would have the effect of operating the ground water basins. Also analyzed were the effects on ground water storage of coordinated operation of Piru, Fillmore, and Santa Paula Basins with potential surface storage developments on tributaries of the Santa Clara River. In the various studies described in this section, consideration was not given to the increased costs that would be experienced by overlying ground water users as a result of lowered ground water levels caused by planned operation of the basins. Such costs were not subject to evaluation with data at hand. There is presented in Table 104 the results of studies of the effects of operation of various capacities of reservoirs at the Topatopa, Devil Canyon and Santa Felicia sites, on ground water storage and levels in Piru, Fillmore, and 4-171 Santa Paula Basins. The surface reservoirs were operated under the uniform releas method and without the release of stored water for maintenance of historic water levels in the ground water basins. The results shown in Table 104 were determined from monthly operation studies for the base period, utilizing methods and pro- cedures described in Chapter II. For all reservoir combinations shown, it was found that Piru, Fillmore, and Santa Paula Basins, although experiencing greater ground water storage depletions than the historical during the drought period, would nevertheless have filled during the wet period. Thus, ground water overdraf would not have resulted in either of the three basins from reductions in supply caused by reservoir operation, and the effect of the increased basin storage depletion would have been to further enhance the developed safe yield of the system. The amounts of net safe seasonal yield from Topatopa, Devil Canyon, and Santa Felicia Reservoirs, under this method of operation were shown in Tables 71 and 100, respectively. 4-172 t/l c/1 < CO ce. LU I— < 3B LO CC O CC CC LU o to LU < CC d< < •-« IX o O LU — • =» CC LU LU _) a o: LU LU LO I— •=£ «* CO 3 < J2 I- LU 2 Lu LO < o O CC Q Z Z =£ < LO • Q W Z CC < o s: < _l X -I O — ■ t— LU < =?e CC — . o X 2 Z £ o «c x l0 LU t— 0. o o O CC o O •- Q LO I- X LU s: z LU •— -t- u_ to — ■*- co (0 X> c - O o o C *- — < on .0 n r +- C t> l/l CO 10 [0 LO X LU .. .. .. 10 CO CO /I X CD 0) CD S.£ O (U k. — ■ o ex u •o CO •> CU k. ■*- I — — CO o u > CO o w Q. 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CO (0 aj a> o o •H -p $ ^, _ -> > ■e * CO 0) XI s Q O +• -t- o & < bu D - 2 o ll-173 A summary of the results of studies made to determine amounts of supplemental water that would be made available to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits through increased use of upstream ground water storage are presented in Table 105. These studies were conducted for the base period under four assumed conditions: (1) with no surface storage develop- ments on tributaries of the Santa Clara River; (2) with Santa Felicia Reservoir constructed to a storage capacity of 100,000 acre-feet, and operated under the uniform release method, without releases for maintenance of historic ground water levels in Piru, Fillmore, and Santa Paula Basins; (3) with Santa Felicia and Topatopa Reservoirs each constructed to a storage capacity of 100,000 acre-feet, and with the same method of operation as in (2); and (4) with Devil Canyon Re- servoir constructed to a storage capacity of 150,000 acre-feet and operated under the same criteria as in (2) both for the joint benefit of the Calleguas-Conejo and Santa Clara River Hydrologic Unit and for the sole benefit of the latter hydr logic unit. It may be noted in Table 105 that consideration was not given to the operation of Piru Basin, other than would occur through the stated method of operating Devil Canyon and Santa Felicia Reservoirs. Examination of Table 104 indicates that the average depth to ground water in Piru Basin substantially ex- ceeds that of both Santa Paula and Fillmore Basins. It is known that certain ove lying users in Piru Basin at the present time are experiencing pumping lifts in in excess of 200 feet. Because of these relatively high pumping lifts, and be- cause of the shorter distance required to convey ground water extracted from Santa Paula and Fillmore Basins to the Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, further consideration was not given to planned operation of ground water storage in Piru Basin, <\ 4-174 T3 L . c to to d > c o o o k_ — Q/l OT -f- tO "O CD > C CD CD O I on— o c I- -♦- ■ a o O C e — — • CO — i (0 - 00 D CO C Q. — tO CO CO +- CD c It) — to — CO — CD O *-l -p ?,co H g >TJ to" E > fa i "O CD ■ C — " 2 4 O (1) CD - c on ■- CO a. D - to c Q_ — to CO CO +• CO c CO I/I — • CO — CO — CO v. (1 c — CO 10 0) w k_ o a> c ■*- ft i0 3 CO »- C to o > — o ■*- D CO Q. • to CO (0 *- CD C co a> u_ on o-4- C0 CO o —<*- ■*- CO I in (j_ — T3 -t- • c to — D -l LP o acr >_ co — ■ CD O e ■ — . in — • us — CD o 10 0. ■ CO CO +- CO c — • >. X> CO CO -Q (0 CO o > LL- CS ■o . L. CO CO • g 3 O 3 O CO +- I -Q-t- "O Z> CD Clfl CO CO u_ >* I c •> <0 CO o c — i »~ CO a. c -k — i_ »_ co * a co co co C C3+- X CO — O —■ c a. j T3 C0< -I- — CO CO 3 ST3 CO C CO 3 CO O • CO i- txn — < in —• co - CD D co c a. — co CO CO +- CD c i oooolplalplp i — - cm r<"\ I LP LP O LP. LP. O O LP. i _i rovi-- o cm ia -a- OOOOOLP.LP.LPLP. LP.OOLP.OOlP.LPO CM -=J"0 ONIA KP. St LP t~- OOOOOOOO O O O O O _3"0 CA O -»- to LP LA O LALPLALPLPLPLPLPLPLALP « cm cm rA rA — r\j n^ .a- OLPOLPOOOOOLPOOLPO — < j- 1 — c» lp — • iaxo on cm cm ^A.3-vo rt CM IA oooooooo oooooooo cono-^o"no > .nO-=i-'a oolPlalp-3-ia— «0 CM -3-sO -(Mm OOOOOOOOO OOOOOOOOO OOOOOO-3-OCO. Q. o CACAO LPLPIP.LPLPLP.LPLPLP.LP LP -3-LP.vOvoF-l*--=J--=>--3-.=t-LPvOl — 00 LPOLPOLPLPIP.LPLPOLPLPOLP KM — ON CM f— IA LP 00 — ■ LP -=»" IA I s - 00 OOOOOOOOOOOOOO OOOOOOOOOOOOOO — < vO LP J" — • — — —• »- •— -3-NM — oi — ^~co^PlOC'^c^^ (M-a-LPCTNvOCMfOiLPf--— •CMOjrP. OOOOOOOOOOOOOO OOOOOOOOOOOOOO — ivOLP-*-«— '-^— •— •— «OOOLP. *0>OnC»nOnOvQ^~CO ct> OOOOOOOOO OOOOOOOOO vO^J-CMI^-LPLPCMOCTv CM— < CO N-CD l^-vO JtAI CMl<\-3-vO00CMN - \-=rLP OOOOOOOO I OOOOOOOO I LP. CT^— LP. < — O CO 00 I «««•.««•.» — . _3-corT\CMNO o^rp. o CO Q. CO o on CO o o u- I (0 k. o CO o o o f^tAOiAi — i^- 1 — r-r^-r^-vOLPLPLp. ^o i~~ oo co o^onvd -oovO^coon-i OOOOOOOOOOOOOO OOOOOOOOOOOOOO O -*SCD(AJONC\i JJ-iALAOO ON(\l«0-ivOOlMOO-<^IIA(\l(\l CMLPnOOO— •ONJ-vOOOOrP.^fLPvO OOOOOOOO OOOOO I OOOOOOOOOOOOO I IAnOOOIAOJCO J-NCMCMCOIAO >ooooooooo »- o o o o » IAO LAO X — • — . CM CO to o > - <0 OOOOOOOOOOOOOO OOOOO OOOO OLPOOO OOOO LfM*- O LP LP LP.O LPCM — . — . CM OOOOOOOOOOOOOO OOOOOOOOO OLPOOOOOOO lA^-OlAOMfNOLAO _ — , _ _ CM LP. LP. LP. LP LP LP.LP.O LAO — . .^3 O K>(~~ o to -t- LPLP.LPLP-LP — -3- J- -3- -a- -a- 3 CO to -. »_ to — > O CO o o o o o > —> o iO a CO o to an CO OOOO ON cm r— CM <0 i. CO CO to-»- (£ 10 3 co Q.T3 o c +- D CO o Q. w o an T3 — O O O O O c »- CO o cow 31 to o u. to CO o -t- c o o o o o C CO OOOO co c oooo o o o o > 0) to CO LP LP ^O vO LP O ao o-n O O i- OOOOO o o o ooooo •k o o u. CM CM CM CM CM c O LP o 5 r — r — r — I — (*- vO 1 — -t- LP LP (0 w >v to Q. •am O o CO ooooo to o o Q. OOOOO 10 o o CO f^cTM^-a 1 ^r iO ON On o -. * • •. » CO 00 — • CM hT\>0 . — , . — • CM to J-vO 00 O CO J- J- an k. .•o k. e o o to b. OOOOO ■— o O ^~ ooooo C O O o CM CM CM CM CM D O LP o •% ■> lb. CO 00 00 00 CO n 1 — 00 I so vo ^o ^o ^o >v — ' *-* O o o o LP LP st LP >0 nO o o o o o o iO x> o o o o o o to • « — < CM CM CO CM CM > LO CO •4- -c c — CO 3b e >» to c — co tj w. QJ — » +• — CO O O > 3 CO O "O xS -t- o — k- 38 an «4 o c b e o a) a> fa i 5 ■P tS -rt e o to to •. *4 to to •> % 2.2. o to »- c X) o £7 to I- CO to D > an .— ■+- co c +- o c — lO to LO k- V o ■— TJ -1- ■4- u_ o to o r <^- to 1 .u T) r k. o O o U— CI) to •o to o ■f- a) ro X. CO 4- o • — o -* co xi CO iH *> 3 i-t d LP Cu ON l-t B) +> *H C o 3 w i-t id E ^ 2 fa o o s g3 Ixi E *. i e fa «H tic O CO to •a in i-i a to oo > to aj to cd ■8 § o o fa 6- 60 o h-175 -. Because of lower specific yield of the water bearing formations and tiler, areal extent, ground water levels in Santa Paula Basin experience a i i ■ abstaritially greater lowering than do levels in Fillmore Basin for' a given ground water draft. This is illustrated in Table 105. It is also shown that with planned operation of Fillmore Basin and lowering of water levels therein, water levels in Santa Paula Basin are also lowered. This effect is the result of reduction in that portion of water supply to Santa Paula Basin originating in Fillmore Basin. Since the objective of planned operation of ground water storage would be to develop as much new water as possible, with a minimum lowering of water levels in the basin being pumped, it would appear that most efficient operation would occur were Fillmore Basin to be operated alone. For the purpose of cost analysis, it was assumed that an additional seasonal ground water draft of 22,000 acre-feet would be imposed on Fillmore Basin, and that this amount of water would be conveyed to the Oxnard Forebay Subunit in the Santa Clara River conduit, described previously. It was also assumed that Devil Canyon Reservoir would be constructed to a capaoity of 150,000 acre-feet, and that this reservoir would be operated under the uniform release method for the joint benefit of the Calleguas-Conejo and Santa Clara River Hydrologic Units, without releases to maintain historic ground water levels in Piru, Fillmore, and Santa Paula Basins. As shown in Table 105, new water made available to the Oxnard Forebay Subunit, by such operation would amount to about 16,000 acre-feet per season. Average ground water levels in Santa Paula and Fillmore Basins would be lowered about 65 feet and 50 feet, respectively, below the levels that would have prevailed in the fall of 1951 with present patterns of land use and water supply development. In the estimates of cost, it was assumed that about 30 acres of presently undeveloped land near the Santa Clara River channel in the westerly portion of Fillmore Basin, in Section 12, Township 3 North, Range 21 West, would be acquired for construction of a well field. The well field site is 4-176 above the flood plain of the Santa Clara River, and is shown on Plate U2. The areal extent of the proposed field would be sufficient to allow placement of the wells at intervals great enough to eliminate substantial mutual interfer- ence during pumping periods. It was assumed that eighteen wells would be drilled, two of which would be used for standby purposes. The wells would be 18-inches in diameter, drilled to a depth of about 220 feet, and gravel packed. Each well pump would be equipped with a 75 horsepower electric motor. From examination of pump test data in Fillmore Basin, it was estimated that each well would produce a minimum of about 1,500 gallons of water per minute, or a little more than 3 second-feet of continuous flow. With 16 wells in operation, the field would be capable of producing about 3*300 acre-feet per month, or about 15 per cent of the total seasonal pumpage. Discharge from the wells would feed into a small regulating reservoir located near Willard Road, and thence into the Santa Clara River Conduit. The following tabulation presents a summary of physical features of the Fillmwre Well Field and appurtenant works, as designed for cost estimating purposes: Wells Number 18 Type 18-inch diameter, gravel packed, and cased Average depth, in feet 220 Distance between wells, in feet U00 Pumping Plants Number 18 Horsepower of motors 75 Depth of bowls, in feet 150 Pump capacity 1,500 gallons per minute Average pumping head, in feet 75 Regulating Reservoir Capacity, in acre-feet 10 Normal water surface elevation, in feet, U.S.G.S. datum 275 4-177 The capital cost of the Fillmore Well Field and appurtenances was estimated to be about $338,000, including cost of the regulating reservoir. The annual costs, including interest and amortization, operation and maintenance charges, replacement, and power charges, were estimated to be about $55,000. It was estimated that the cost of new water available for conveyance to the Oxnard Forebay Subunit would be about $3*50 per acre-foot. These costs do not include any compensation for unreasonable expense to overlying ground water users in Fillmore and Santa Paula Basins, resulting from the planned operation of Fillmore Basin. It is not believed that, with the aforementioned increased ground water level lowering of 65 feet and $0 feet, in Santa Paula and Fillmore Basins, respectively, any such unreasonable expense would occur. Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins . It was shown in Chapter II that with the present pattern and rate of pumping from Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins, ground water storage depletion in Oxnard Forebay Basin must be limited to about 20,000 acre-feet to prevent formation of a trough in the piezometric surface in the Oxnard aquifer, and to prevent the intrusion of sea water to the aquifer. It appears that a trough also will form in the Fox Canyon aquifer if ground water storage in Oxnard Fore- bay Basin is depleted in excess of 20,000 acre-feet. The Oxnard and Fox Canyon aquifers apparently lack capacity to transmit xvater from the forebay to the pressure areas at sufficient rates to meet the demands of present pumping drafts. For this reason, consideration was given to modification of the present pattern of ground water pumping, so that lands near the coastal front would be served with water pumped from Oxnard Forebay Basin and conveyed thereto by surface conduit. In effect, an artificial surface conveyance unit of adequate capacity would be substituted for the presently utilized natural aquifers of inadequate conveyance capacity. 4-173 Under certain conditions, such a change in pumping pattern could eli- dnate the threat of sea-water intrusion to a confined aquifer. In the case of -he three basins under consideration, however, there are several factors which ppear to make such a plan infeasible. Without some provision for supplying )xnard Forebay Basin with an additional water supply during drought periods, it .s indicated that ground water levels in the basin would be drawn down below sea .evel. This would take place regardless of any modification in the pattern of mmping from the three basins. Cessation of ground water pumping near the :oast, particularly in the vicinities of submarine canyons near Port Hueneme md Point Mugu, would tend to mitigate the immediate threat of loss of aquifer itility through sea-water intrusion. Nevertheless, from consideration of studies lescribed in Chapter II, it appears that a trough would still form in the Oxnard iquifer, and that under conditions of longer and more severe droughts than that Trom \9hk-h5 through I9f>0-5>1, and with increased water supply utilization in the Dxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, sea water might Invade portions of the Oxnard and Fox Canyon aquifers still being actively pumped. Thus, regardless of instituted changes in the pattern of pumping from ibhe three ground water basins, the threat of sea-water intrusion can only be eliminated with the development of supplemental water and its delivery to the Dxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits, during periods of drought. With the development of supplemental water, either in upstream surface or ground water reservoirs, and conveyance of the water to the Oxnard Forebay Subunit, either by conduit or by natural channel of the Santa Clara River, two possible methods for its distribution in the Oxnard Plain and Pleasant Valley Subunits were given consideration: (l) Utilization of Oxnard Forebay Basin as a regulating reservoir, and conveyance of the supplemental water to and its dis- tribution in areas of need by means of the presently utilized natural aquifers ; 4-179 and, (2) conveyance of the supplemental water to and its distribution in areas of need by means of a surface distribution system similar to that described under the section of this chapter entitled "Conveyance and Distribution of Supplemental Water" . Under the first of the foregoing methods of conveyance and distribution, the present pattern of pumping ground water from the three basins would i.ot be modified. However, to eliminate the problem of inadequate aquifer transmissi- bility, it would be necessary to maintain ground water levels in Oxnard Forebay Basin at 60 feet above sea level or higher, in order to maintain a seaward gradient in the piezometric surface of the Oxnard aquifer and to prevent forma- tion of a trough therein. As stated, this would limit ground water storage depletion in Oxnard Forebay Basin to about 20,000 acre-feet. If these criteria could be met, such a plan of conveyance and distribution of supplemental water would be the least expensive to put into effect. However, studies described elsewhere in this chapter indicate that insufficient water can be developed either in upstream surface or ground water reservoirs to maintain ground water levels in Oxnard Forebay Basin at the prescribed elevation. Furthermore, with maintenance of ground water levels in Oxnard Forebay Basin at an elevation of 60 feet or higher, utility of the basin as a natural regulator of surface runoff in the Santa Clara River would be almost entirely destroyed. In addition, it was estimated that a substantial portion of the supplemental water supply stored in Oxnard Forebay Basin would be lost for beneficial use through increased sub- surface outflow to the ocean. For these reasons, it was concluded that conveyance and distribution of supplemental water in areas of need in the Oxnard Plain and Pleasant Valley Subunits should be accomplished through the construction of a surface conveyance and distribution system. A description of general features and the estimated costs of such a system have been presented previously in this chapter. 4-180 I Simi and East and West Las Posas Basins . Although it was estimated hat there is little opportunity for further conservation of local water supplies n the Calleguas-Conejo Hydrologic Unit, studies of the Division of Water esources and of the Soil Conservation Service of the United States Department f Agriculture indicated that presently dewatered ground water storage capacity n the Simi and East and West Las Posas Basins could be utilized to regulate mported water supplies. Utilization of these basins for such purpose would nvolve the construction of spreading facilities in areas where the soil profile s of such character as to allow rapid infiltration of water applied on the sur- ace, and where no continuous underlying impervious strata exist that would ■revent water applied on the surface from reaching pumped aquifers. Furthermore, here would have to be adequate carry-over storage capacity available in the ewatered portions of the basins to satisfactorily regulate the imported water. During 1951 and 1952, the Soil Conservation Service conducted an inves- igation of possible spreading areas in Zone 3 of the Ventura County Flood ontrol District. This investigation included studies of infiltration rates and nvestigation of soil profiles to determine the suitability of various areas for preading. The results of these studies have been published in a report entitled Ground Water Replenishment by Penetration of Rainfall, Irrigation, and Water preading in Zone 3, Ventura County Flood Control District, California", dated pril, 1953. Although the studies encompassed most of the Calleguas-Conejo ydrologic Unit and a portion of the Pleasant Valley Subunit of the Santa Clara iver Hydrologic Unit, the ensuing discussion of their results refers only to the ijimi and East and West Las Posas Basins, 'wherein it was concluded the most avorable geologic conditions prevail for the spreading, infiltration, and storage f supplemental water. 4-181 The Soil Conservation Service estimated that there were about 725 acres of land overlying Simi Basin suitable for water spreading purposes. Of this area, it was concluded that about 590 acres would have a continuous infiltration capacity of about one foot of depth of water per day, and that about 135 acres would have a continuous capacity of about two feet of depth of water per day. In East Las Posas Subunit, about 2,320 acres of land were estimated to have a continuous infiltration capacity of about one foot of depth of water per day, with 2,lt80 acres having a capacity of about two feet of depth of water per day. Loca- tions of these areas are shown on a plate in the foregoing report. In Simi Basin, it was estimated that there were about 5l>000 acre-feet of dewatered ground water storage capacity in the fall of 1951 between ground water levels prevailing at that time and a depth of 25 feet below ground surface. Similar estimates could not be made for the several aquifers in East and Vilest Las Posas Basins, although the total dewatered storage capacity therein in the fall of 1951 was probably in the order of magnitude of that in Simi Basin. As described earlier in this chapter, consideration was given to the utilization of Devil Canyon Reservoir with a storage capacity of 150,000 acre- feet, for the joint benefit of both the Santa Clara River and Calleguas-Conejo Hydrologic Units, and with diversion of a portion of the conserved water to the Calleguas-Conejo Hydrologic Unit through the Piru-Las Posas Conduit. It was indicated that the most economical capacity of this conduit would be about 80 second-feet. It xvas estimated that to equalize the discharge from an 80 second- foot conduit about lij.0,000 acre-feet of regulatory storage capacity would be required in the Calleguas-Conejo Hydrologic Unit. Regulation of the supplemental water supply could be effected either in surface storage or in ground water storage. Reconnaissance type investigation indicated that the cost of construct- ing such storage capacity in surface reservoirs would be prohibitive. Therefore, consideration was given to construction of water spreading facilities and obtaining the required regulation in ground water storage. 4-182 For cost estimating purposes, it was assumed that 30 second-feet of 1 water spreading and infiltration capacity would be constructed in the Simi Sub- unit, and that 50 second-feet of such capacity would be constructed in the East Las Posas Subunit. With a Piru-Las Posas Conduit of 80 second- foot discharge capacity, an average supplemental water supply of about 7,550 acre-feet per season would be made available in the Simi Subunit, and about 12,550 acre-feet per season in the East Las Posas Subunit, which amounts would be sufficient to eliminate present ground water overdrafts in Simi and East and West Las Posas Basins and to provide some water for future growth. Regulation of these supple- mental supplies would require about 50,000 acre-feet and 90,000 acre-feet of storage capacity, respectively. Assuming that there would be no substantial rise in ground water levels during future wet periods, it appears that suffi- cient storage capacity for this purpose would be available in Simi Basin. However, whether there is 90,000 acre-feet of dewatered ground water storage capacity available in East and West Las Posas Basins is questionable. For cost estimating purposes, it was assumed that about 70 acres of land would be acquired for spreading purposes near Dry Canyon, in the north- central portion of Simi Valley. With an infiltration capacity of one foot of depth of water per day, these proposed spreading grounds would be capable of infiltrating a continuous discharge of 30 second-feet. Similarly, about 50 acres of presently undeveloped land would be acquired in Happy Camp Canyon in the East Las Posas Subunit, near the southerly portal of the previously described Happy Camp Canyon tunnel, a feature of the Piru-Las Posas Conduit. It was esti- mated that these lands would have an infiltration capacity of about two feet of depth of water per day, which irould allow spreading and infiltration of a contin- uous flow of 50 second-feet. The spreading works would consist of a series of ponds, created by earthen dikes and interconnected with culverts. Maximum depth of water in the ponds would be 5 feet, and 2 feet of freeboard would be provided. 4-183 The location of the two spreading grounds and of laterals thereto from the Piru- Las Posas Conduit are shown on Plate 1*2. The costs of the Dry Canyon spreading grounds and of the lateral from the Piru-Las Posas Conduit thereto were estimated to be 0266,000 and $1,619,000, respectively, or a total of $1,885,000. The cost of the Happy Camp Canyon spreading grounds was estimated to be $129,ltOO. Geologic investigation indicated the desirability of spreading and infiltrating water in Simi Valley at a location in the vicinity of Tapo Canyon, further east than the considered spreading grounds. However, lack of head at the southerly portal of the Happy Camp Canyon Tunnel precluded conveyance of the supplemental water to Tapo Canyon, without provision for pumping. It should be pointed out that prior to construction of spreading works at the considered site in the Simi Subunit, drilling should be undertaken to definitely ascertain its suitability. At the Happy Camp Canyon site, a refrac- tion seismic survey conducted by the Division of Water Resources confirmed sparse geologic evidence that the Grimes Canyon member of the San Pedro formation outcropped in the alluvium, and that the site, therefore, was apparently suit- able for spreading grounds from the geologic standpoint. It appears that percolation of water in the Grimes Canyon aquifer would also replenish the over- lying Fox Canyon aquifer. Whether or not the rate of movement of ground water in the two aquifers would be sufficient to prevent a mound from building up beneath the Happy Camp spreading grounds, and thereby reducing the estimated spreading capacity could not be determined. If after a period of operation there were such an occurrence, construction of additional spreading grounds in the outcrop of the Fox Canyon aquifer to the west of Happy Camp Canyon would be required to equitably distribute the water throughout East and West Las Posas Basins. A similar condi- tion could arise in the considered spreading grounds near Dry Canyon in the Simi Subunit . 4-184 It should be pointed out that artificial replenishment of the Fox anyon aquifer in East and West Las Posas Basins would also benefit Pleasant alley Basin in the Santa Clara River Hydrologic Unit. As was stated in Chapter I, it appears that there is hydraulic continuity in the aquifer between these asins, and that Pleasant Valley Basin presently receives a portion of its eplenishment by underflow from East and West Las Posas Basins through the Fox anyon aquifer. 4-185 Pla.ns for Importation by Means of Feather River Project As previously described, the State-wide Water Resources Investigation, proceeding under authorization of Chapter 1541, Statutes of 1947 and under direction of the State Water Resources Board, has as its objective the formulatic of The California Water Plan. The Feather River Project resulted from these State-wide studies, and was proposed as a feature of The California Water Plan. Under provisions of this project, supplemental water would be made available to meet the probable ultimate water requirements of Ventura County. Features of the Feather River Project are described in detail in a publication of the State Water Resources Board entitled "Report on Feasibility of Feather River Project and Sacramento-San Joaquin Delta Diversion Projects Proposed as Features of The California Water Plan", dated May, 1951. These projects were authorized and adopted by the 1951 Legislature, in an act which authorized their construction, operation, and maintenance by the Water Project Authority of the State of California. Provision was made in the authorizing act for financing construction of the proposed works through issuance and sale of revenue bonds, and through receipt of contributions from other sources. In Kay, 1952, the Legislature provided $800,000 by budgetary appropriation to the Divisio of Water Resources for necessary investigations, surveys, and studies, and pre- paration of plans and specifications for the Feather River and Sacramento-San Joaquin Delta Diversion Projects. A similar appropriation in the amount of &750,000 i«is made in 1953. There is presented in this section a summary description of the fore- going projects, the estimated costs thereof based on prices prevailing in 1951, and the provisions made therein for supplying supplemental water to Ventura County. It should be mentioned that continuing studies are being made of alternative designs and locations for project features, and as a result, works 4-186 finally constructed may differ from those described herein. The multipurpose Feather River Project contemplates construction of a gravity concrete dam, 710 feet in height above stream bed, at a point on the Feather River 1.7 miles below the junction of the North and Middle Forks and 5.5 miles above the City of Oroville. The dam will have an overpour spillway. It will create a reservoir of 3,500,000 acre-foot storage capacity, and will provide a large measure of control of the runoff of the Feather River for purposes of conservation, flood control, hydroelectric power generation, and other ben- eficial uses. Provision will be made for a hydroelectric power plant located at the dam, of 440,000 kilowatt capacity, and for an afterbay dam, and power plant of 2$,000 kilowatt capacity, located four miles downstream from the main dam. The project also includes construction of a power transmission line from the Oroville power plants to Bethany, near Tracy in San Joaquin County, and a switch yard at the terminal. A channel crossing of the Sacramento-San Joaquin Delta will be required to carry Oroville Reservoir releases from the Sacramento River to the San Joaquin River Delta, for subsequent transmission to water- deficient areas in other parts of California. With Oroville Reservoir operated for flood control, and to supply water for all requirements in the Feather River Service Area and for prior rights in the Sacramento-San Joaquin Delta, sufficient releases could be made to supplement surplus waters in the Delta so as to permit a continuous diversion of about 3,900 second-feet from that area, or approximately 2,845,000 acre-feet per season. Under the plan proposed in the 1951 report for serving areas of deficiency, water would be diverted from the San Joaquin Delta at sea level, the point of diversion being on Old River about five miles northwest of Tracy. The water would be lifted to a canal at an elevation of 225 feet, which would parallel the Delta- Mendota Canal southerly to a point near the south line of Merced County, where a second pumping plant would lift the water to an elevation of 400 feet. The 4-187 canal would then continue southerly approximately on grade contour along the we side of the San Joaquin Valley to the Buena Vista Hills, where another pumping plant would lift the water to an elevation of 500 feet. Four additional pumpin, lifts, and a canal, would deliver the water at Pastoria Creek, three miles east of Grapevine at an elevation of 1,500 feet. At various points in the San Joaqu: Valley, diversions would be made from the conduit to serve lands requiring sup- plemental water. A series of pumping lifts at Pastoria Creek would raise the wat to an elevation of 3,375 feet, and to the portal of the first of two tunnels tht would convey the water through the Tehachapi Mountains to a point on the divide between the Santa Clara River Basin and Antelope Valley near Quail Lake. Near this point, releases from the conduit could be conveyed via a short tunnel to a tributary of Piru Creek, and thence to service areas in Ventura County. The mair conduit would continue southerly in a series of canals, tunnels, and siphons to its terminus at a tributary of the Tia Juana River in San Diego County at a dis- tance of about 567 miles from the point of diversion in the San Joaquin Delta. E route it would serve supplemental water to lands in the Lahontan, Colorado Deser and South Coastal Areas. In connection with the delivery of water from the conduit, hydroelectric power could be developed at several points on the Pacific slope of southern California. Plate 39, entitled "Feather River Project," shows the location of Oroville Reservoir, and the general alignment of the San Joaquin Valley-Southern California Diversion conduit. Detailed estimates of cost of the Feather River Project are included in the feasibility report, but are currently being revised. A summary of estima ed capital costs of the project, as presented in the 1951 report, is given in Table 106. The estimates of capital cost were based on prices prevailing in 1951, and included allowances of 10 per cent for administration and engineering, 15 per cent for contingencies, and 3 per cent for interest during one-half of the estimated construction period. 4-188 TABLE 106 SUMMARY OF ESTIMATED CAPITAL COSTS OF FEATHER RIVER PROJECT AND SACRAMENTO-SAN JOAQUIN DELTA DIVERSION PROJECTS Oroville Dam and Reservoir $ 342,626,000 Oroville Power Plant 64,509,000 Oroville Afterbay and Power Plant 14,146,000 Oroville Transmission Line and Terminal Switchyard 19,734,000 Delta Cross Channel 3,798,000 Santa Clara-Alamada Diversion 31,065,000 San Joaquin Valley-Southern California Diversion 794.509*000 TOTAL fa, 270,387, 000 It was assumed in the cost analyses presented in the feasibility : report that the Federal Government would contribute to the Feather River Project the sum of -^50,000,000, without reimbursement, in the interest of flood control. Substantial flood control benefits to lands and communities along the Feather River would result from operation of the project. There is a well-established federal policy for such financial participation in projects of this character. It was also assumed that the State of California would contribute the sum of $86,926,000 for the acquisition of lands, easements, and rights of way, and for the relocation of utilities. This contribution would also be non- reimbursable . Such financial participation by the State would be justified under the policy set forth in the State Water Resources Act of 1945, as amended. If these federal and state contributions to the Feather River Project were forthcoming, capital costs shown in Table 106 would be reduced to ^1,133,461,000. Based on this estimated capital cost, it was further estimated with 1951 report that annual costs of the project would be about ^108,775,000 with an 4-189 assumed 2 per cent interest rate, and about $114,539,000 with an assumed 3 per cent interest rate. The annual costs included interest repayment, replacements, operation and maintenance, power charges, insurance, and general expense. In th cost analysis, it was shown that annual costs based upon the 2 per cent interest rate could be met under the schedule of revenues shown in the following tabula- tion, but that an annual deficit of some $1,898,000 would occur with the 3 per cent interest rate. Item Unit Charge Annual Revenue 311,000 acre-feet of new water delivered to service area along Feather River 127,000 acre-feet to Santa Clara- Alameda Diversion 945,000 acre-feet to San Joaquin Valley 1,773,000 acre-feet to southern California 1,670,000,000 kilowatt-hours Terminal Substation Total $112,641,000 Based on the foregoing assumptions, the estimated cost of water from the Feather River Project available for diversion to Ventura County from the San Joaquin Valley-Southern California Diversion Conduit would be about $50 per acre foot. The stated purpose of the Feather River Project is to furnish water as needed to supplement existing supplies. In the cases of both the San Joaquin Valley and southern California, it would provide supplemental rather than sub- stitutional water for otherwise developed water supplies, including California's rights in and to the waters of the Colorado River in the amount of 5,362,000 acre-feet annually. In this connection, studies made as a part of the current State-wide Water Resources Investigation indicate that the probable ultimate 4-190 $ 1.00 $ 311,000 20.00 2,540,000 10.00 9,450,000 50.00 88,650,000 0.007 11.690,000 supplemental water requirements of the San Joaquin Valley and southern California will be much larger than can be met by the Feather River Project as previously described. For this reason Oroville Reservoir is considered to be only an initial storage unit in The California Water Plan, and additional reservoirs and increased conduit capacities will be provided as the demands of an increasing population dictate. The plan of utilizing the delta of the Sacramento and San Joaquin River as a point of diversion of surplus waters developed in northern California for export to areas of need has many practical advantages. The diversion point is below all riparian owners and users of water in the basin above the delta, and therefore is not subject to objection by such owners. The delta channels are recipient of all the flood flows and return waters from an area of about 50,000 square miles. The supply to the delta, therefore, is not dependent on the vagaries of a single stream. Water developed in any part of the Sacramento or San Joaquin River basins could find its way by gravity to the delta, and the same is true of surplus water that might be transferred from the North Coastal Area to the Sacramento River Basin. Advantages of the planned conduit to the San Joaquin Valley and southern California are that it would traverse, in large part, undeveloped terrain, would not interfere with the operation of existing water supply systems, would not involve any exchange of waters, and would be located in a position to furnish by gravity from the conduit additional water supplies to existing systems, and to new areas capable of development and in need of water. It is feasible of construction from both engineering and geological standpoints, capable of development to serve supplemental water to meet the ultimate needs of the west and southern sides of the Upper San Joaquin Valley, the South Coastal Area including Ventura County, and the desert areas in Los Angeles, San Bernardino, and Riverside Counties. 4-191 Studies are being continued to select a final alignment and grade for San Joaquin Valley-Southern California Diversion Conduit, and al30 to determine the most feasible manner in which supplemental water from the project could be diverted for use in Ventura County. From the results of studies described in this bulletin, it was estimated that the probable ultimate requirement for im- ported water in Ventura County will be in the order of 200, 000 acre-feet per season, which amount could be readily supplied from the San Joaquin Valley- Southern California Diversion Conduit when operated at ultimate capacity. For illustrative purposes, there is shown on Plate 40 a possible profile, resulting from preliminary reconnaissance, for the foregoing diver- sion to Ventura County. The location of this diversion should be considered as tentative, and subject to considerable modification after studies currently underway have been completed. Commencing at a turn-out from the San Joaquin Valley-Southern California Diversion Conduit, at about an elevation of 3,325 feet in the upper end of the Antelope Valley near Quail Lake, water for diver- sion to Ventura County would discharge into a small regulating reservoir having a normal water surface elevation of about 3>324 feet. Discharge from the reservoir would be conveyed a distance of about 8,200 feet in a southerly direction in a canal. The canal would discharge into a tunnel about 21,500 feet in length through the Piru Mountains. From the outlet of the tunnel, the conduit would consist of about 2,000 lineal feet of reinforced concrete siphon, followed by a tunnel about 4, 600 feet in length, which would discharge into the penstock of Power Plant No. 1, located near Highway 99 at an elevation of about 2,480 feet. About 800 feet of power drop would be available at this plant. Discharge from Power Plant No. 1 would enter Canada de Los Alamos, a tributary of Piru Creek, and would follow that tributary and Piru Creek to a poiri about 17,400 feet downstream from their confluence. At this point the flow would 4-192 be diverted to a tunnel about 11,200 feet in length, from which it would dis- charge into the penstock of Power Plant No. 2, located on Piru Creek about 2.6 miles upstream from the Ventura-Los Angeles County Line, at an elevation of about 1,885 feet. The power drop available at this plant would be about 370 feet. Water from the afterbay of Power Plant No. 2 would be diverted to a tunnel about 13,900 feet in length, and thence into the penstock supplying Power Plant No. 3. This plant would be located on Piru Creek some 7.0 miles upstream from the Devil Canyon dam site, at an elevation of about 1,325 feet. Approx- imately 520 feet of power drop would be available at Power Plant No. 3. Discharge from Power Plant No. 3 would enter Piru Creek and flow to terminal storage at Devil Canyon Reservoir. As previously described, this reservoir would have a storage capacity of about 150,000 acre- feet. Its normal water surface elevation would be about 1,265 feet. As an alternative to terminal regulation at Devil Canyon Reservoir, consideration was given to utiliza- tion of Blue Point Reservoir, constructed to a storage capacity of about 50,000 acre-feet for regulation of imported Feather River Project water. Although the alignment for the diversion to Ventura County, as des- cribed, would be advantageous from the standpoint of developing hydroelectric power, revenue from the sale of which could be used in reducing costs of the imported xrater supply, further studies may show that construction of the several required tunnels of substantial length is unfeasible. If such should be the case, a gravity diversion to Ventura County, with a minimum of tunnel, could be effected from the foregoing regulating reservoir near Quail Lake. Discharge from the regulating reservoir would then largely follow the natural channels of Piru Creek and its tributaries to Devil Canyon Reservoir. From Devil Canyon Reservoir, gravity service of the imported water could 4-193 be provided most areas of need in the Calleguas-Conejo, Malibu, and Santa Clara River Hydrologic Units, and a substantial portion of those in the Ventura Hydrologic Unit. A diversion to the Calleguas-Conejo and Malibu Hydrologic Units could be effected through a conduit from Piru Creek to Happy Camp Canyon, similar to that described previously. It would also be possible to supply supplemental water through this system to that portion of the Malibu Creek drainage area within Los Angeles County, including the community of Malibu and adjacent resort areas. Gravity water service could also be provided to Santa Barbara County in the vicinity of Carpenteria. 4-194 Plans for Importation by Means of Metropolitan. Water District of Southern California A source of supplemental water for Ventura County is immediately yailable in the Colorado River through the facilities of the Metropolitan Water istrict of Southern California. Colorado River water is now imported to the outh Coastal Area by the Metropolitan Water District from Lake Havasu, an arti- icial reservoir on the Colorado River created by Parker Dam. The importation s made through an aqueduct about 2i|2 miles in length to terminal storage in .ake Mathews, about nine miles southerly of the City of Riverside. From Lake Mathews the imported water is distributed to many public water service agencies .n Los Angeles, San Bernardino, Riverside, Orange, and San Diego Counties. In lieu of immediate construction of local conservation works in Centura County, consideration was given to the annexation of Ventura County to ;he Metropolitan Water District of Southern California for the purpose of Obtaining supplemental water to eliminate present water supply deficiencies and :o provide for anticipated future water needs. Metropolitan Water District of Southern California The Metropolitan Water District of Southern California was organized In 1928, after the State Legislature had passed an enabling act in 1927. In L931, when bonds in the amount of $220,000,000 were voted for financing the Colorado River development, the District comprised 13 member cities, having a total assessed valuation of slightly less than $2,500,000,000. As of August 20, 1953, the assessed valuation was estimated to be ;|6, 015,500,000, and the Dis- trict comprised 13 member cities, six municipal water districts, and the San Diego County Water Authority. Actual construction on the Colorado River Aqueduct started in January, 1933. The first delivery of softened Colorado River water, from the softening and treatment plant located near La Verne, was made to the City of Pasadena in June, 19U1. h-195 The right of the Metropolitan Water District of Southern California to waters of the Colorado River, as determined under provisions of the Colorado River Compact, Boulder Canyon Project Act, and in accordance with the Seven-P. Water Agreement which was executed among interested California parties in August, 1931 i is 1,112,000 acre-feet per annum, including the right of the San Diego County Water Authority of 112,000 acre-feet per annum. During 1952-5>3, about 162,000 acre-feet, or ll*.6 per cent of the foregoing entitlement of the District to Colorado River water, were sold by the District. Section 3>-l/2 of the Metropolitan Water District Act provides as follows: "Each city, the area of which shall be a part of any dis- trict incorporated hereunder, shall have a preferential right to purchase from the district for distribution by such city, or any public utility /therein empowered by said city for the pur- pose, for domestic and municipal uses within such city a portion of the water served by the district which shall, from time to time, bear the same ratio to all of the water supply of the district as the total accumulation of the amounts paid by such city to the district on tax assessments and otherwise, excepting purchase of water, toward the capital cost and operating expense of the district's works shall bear to the total pay- ments received by the district on account of tax assessments and otherwise, excepting purchase of water, toward such capital cost and operating expense." The preferential right of a member to available water, therefore, is proportional to the ratio of total tax payment actually made by that member to the total tax payments actually made by all members of the District. Thus, a newly annexed area would have an entitlement based only on the taxes actually paid to the District. However, entitlements so determined do not at the present time limit the quantities of water that may be obtained from the District, but would be effective when utilization of water by the District equals the ultimate capacity of Colorado River Aqueduct, if no other water supply is made available in the meantime. Procedure for annexation of Ventura County to the Metropolitan Water District would include formation of a public district with appropriate powers U-196 ,id embracing the entire County. If such a district were formed, the assessed aluation of the County would be used in estimating entitlements to water under ne preferential right principle, and Ventura County's share in the Colorado iver water supply would be determined thereby. In order to estimate the quan- tity of water to which Ventura County would be entitled, with the Colorado River queduct operating at its ultimate capacity, the entire Colorado River supply n use, and disregarding losses, it was assumed the ratio of Ventura County's ssessed valuation to that of the entire Metropolitan Water District, including hat of Ventura County over a l|0-year period commencing in 1929, would be pro- ortional to the estimated 1953-5*4 ratio of $306,000,000 to $6,321,500,000. y multiplying the District's entitlement of 1,212,000 acre-feet per season of dorado River water by this ratio, it was indicated that Ventura County would >e entitled to a water supply of about 59*000 acre-feet per season under the tated conditions. It is apparent that the foregoing supplemental water supply would be Jiadequate to meet present requirements in Ventura County. However, in this egard, the following statement of policy by the Metropolitan Water District's 3oard of Directors on December 16, 1952, is considered pertinent: "The Metropolitan Water District of Southern California is prepared, with its existing governmental powers and its present and projected distribution facilities, to provide its service area with adequate supplies of water to meet expanding and increasing needs in the years ahead. The district now is pro- viding its service area with a supplemental water supply from the Colorado River. When and as additional water resources are required to meet increasing needs for domestic, industrial, and municipal water, the Metropolitan Water District of Southern California will be prepared to deliver such supplies. "Taxpayers and water users residing within The Metropolitan Water District of Southern California already have obligated themselves for the construction of an aqueduct supply and dis- tribution system involving a cost in excess of ^350,000,000. This system has been designed and constructed in a manner that permits orderly and economic extensions and enlargements to deliver the district's full share of Colorado River water as well as water from other sources as required in the years U-197 ahead. Establishment of overlapping and paralleling govern- mental authorities and water distribution facilities to service Southern California areas would place a -wasteful and unnecessary financial burden upon all the people of California, and parti- cularly the residents of Southern California." This policy statement may be interpreted in light of recent developments relatii to importation of supplemental water to southern California, which have been described hereinbefore under the section entitled "Plans for Importation by Means of Feather River Project". Untreated Colorado River water, which has been considered for importa- tion to Ventura County, is of acceptable mineral quality for irrigation use. Total mineral solubles in the supply delivered to the Metropolitan IVater Dis- trict's system have averaged between 750 and 800 parts per million during the past five j'ears. The water has a low concentration of boron, and a moderate percentage of sodium ion. However, the concentrations of total mineral solubles are such that some soil types to which the water might be applied would require adequate leaching to prevent excessive accumulation of minerals. For donatio use, Colorado River water would require chlorination, as do practically all raw waters. Softening treatment would enhance its suitability for such use. A typical analysis for constituent characteristics of Colorado River water, relatec to its domestic use, is presented in the following tabulations Total hardness, as parts per million of CaCO: 33U Non-carbonate hardness, as parts per million of CaCO^ . 21f> Alkalinity, as parts per million of CaCO^ . • . 119 Magnesium, as parts per million • • 30 pH 8.3 As a matter of interest, it may be noted that the mineral quality of Colorado River water compares favorably with that of local supplies throughout Ventura County. U-198 onveyance of Imported Water tc Ventura County Discussion with engineers of the Metropolitan Vdater District has indi- ated that the nearest source of Colorado River water for Ventura County would '3 a take-off point on a conduit currently being considered for construction rom Lake Mathews to Orange County, designated the "Lower Orange County Feeder". .Lthough final alignment of this conduit has not been fixed, for cost estimating orposes it was assumed that it would follow the general alignment shown on Late 25, and that the take-off for Ventura County would be in Walnut Canyon bout 10 miles southeast of the City of Fullerton. The assumed elevation of Lower Orange County Feeder at the take-off Dr Ventura County was taken as 9^0 feet. From this initial point, preliminary onsideration was given to three possible conduit routes to Ventura County, hese routes were as folloxvs: (l) westerly to the coast, and thence northerly Long U. S. Highway 101 Alternate to the coastal plain of the Santa Clara River alley; (2) northwesterly to the vicinity of Glendale, and thence along U. S. ighway 101 to Cone jo Valley; and (3) northwesterly to the vicinity of Glendale, rid thence across San Fernando Valley to Chatsworth and to Simi Valley. It was etermined that gravity supply could be obtained at the Oxnard Plain utilizing he first of the foregoing routes. The second and third routes considered would equire pumping. The third route, in addition to the pumping installations, ould require a tunnel through the Santa Susana Mountains into Simi Valley, econnaissance type estimates of cost indicated that to reach a common terminal torage site in Ventura County, which would be required to obtain maximum tility of such a conduit, there would be little difference in cost of the three outes. However, the third route would be the most favorable from the standpoint f distribution of water in the Calleguas-Conejo Hydrologic Unit. This latter oute, therefore, was chosen to illustrate the costs of delivering Colorado River ii-199 water for use in Ventura County. The conduit for conveying Colorado River water to Ventura County is hereinafter referred to as the Ventura County Aqueduct. Preliminary estimates of cost were prepared for conduits with capaci- ties of 25, 50, 75, 100, and 150 second-feet, respectively. Commencing at the aforementioned point on the proposed Lower Orange County Feeder, at an elevation of 9h0 feet, the Ventura County Aqueduct would extend generally in a northwest- erly direction, a distance of about li38,800 feet or about 83 miles, to terminal storage at the Cone jo reservoir site on Cone jo Creek. It would include about 15,200 lineal feet of tunnel through the Santa Susana Mountains at an elevation of 1,077 feet. From the take-off, the line would extend northwesterly down Walnut Canyon, and would cross beneath the Santa Ana River bed at station mile 3» From the river, it xvould extend northwesterly through the town of Yorba Linda and pass northeast of the town of Brea, to VJhittier Boulevard at station mile 13. From this point the aqueduct would parallel Whit tier Boulevard, passing through the City of Whit tier, and crossing the San Gabriel River at station mile 2k» At station mile 25, it would turn northerly to Beverly Boulevard, and then pro- ceed westerly along that boulevard, crossing the Rio Hondo at station mile 26. At station mile 28 the aqueduct would leave Beverly Boulevard and extend north- westerly through the City of Los Angeles, crossing the Arroyo Seco at station mile 36. From the Arroyo Seco, it would follow the alignment of San Fernando Road through Glendale to station mile 1*2, where it would turn westerly, following the left bank of the Los Angeles River to station mile h5» At this point, the aqueduct would turn northwesterly and pass through the City of Burbank, to Burbank Boulevard at station mile 1|8, and then continue westerly along the alignment of Burbank Boulevard, passing beneath the improved channel of Tujunga Wash at station mile 50, to Fulton Avenue at station mile 52. U-200 From the intersection of Fulton Avenue and Burbank Boulevard, the onduit would extend northerly to station mile 52, where Pumping Plant No. 1 'ould be located. From this plant, the aqueduct would continue northerly to :oscoe Boulevard at station mile 55. From the intersection of Fulton Avenue and ,oscoe Boulevard, it would extend westerly along Roscoe Boulevard to station die 66, where Pumping Plant No. 2 would be located, at a site about one mile outh of Chatsworth Reservoir. From this plant, the conduit would continue ester ly along Roscoe Boulevard to station mile 67, where it would turn north- esterly at Dayton Canyon, following the North Fork of Dayton Canyon to the outheasterly portal of the aforementioned Santa Susana Tunnel at station mile 68. The northwesterly portal of the Santa Susana Tunnel would be on the :outherly side of Simi Valley, about 1.5 miles southeast of the town of Santa iusana. From this portal, the aqueduct would extend westerly along the south ;ide of Simi Valley to station mile 77, where a take-off for the Oak Canyon Ter- dnal Reservoir would be located. Continuing westerly, the conduit would cross i saddle between the Calleguas and Conejo Creek drainage areas at an elevation of ibout 980 feet, and would terminate at a tributary of the North Fork of Cone jo Jreek at about station mile 83. From this point, water discharged from the aque- tuct would follow the natural watercourse to terminal storage at Conejo Reservoir, 'he proposed Conejo Dam would be at station mile 86. For illustrative purposes, there are described herein design features "or a Ventura County Aqueduct having a discharge capacity of 150 second-feet, 'late 111, entitled "Profile of Proposed Ventura County Aqueduct to Connect with Jystem of Metropolitan Water District of Southern California - Capacity 150 Second- feet" shows a profile of this conduit from Walnut Canyon to Conejo Reservoir. )esign features of the other conduit capacities considered would be similar in ill respects except size. The conduit with discharge capacity of 150 second-feet irould comprise about l;lii,800 lineal feet of 72-inch diameter, about 5,000 lineal U-201 feet of ij2-inch diameter, and about 3>800 lineal feet of 3 6- inch diameter lock joint concrete cylinder pipe. The 72-inch diameter pipe would extend from the take-off at Walnut Canyon to the saddle between the Calleguas and Conejo Creek drainage areas, from which point the smaller size pipes would be installed to dissipate pressure head prior to discharging into the natural watercourse. Velocity in the 72-inch diameter pipe would be about 5. 3 feet per second, and the slope of the hydraulic grade line would be about 0.001. Maximum pressure head in the conduit would be about 600 feet at a point near the San Gabriel River crossing. Releases to the Ventura County Aqueduct from the Lower Orange County Feeder would be effected by a bifurcation structure with gate valve regulation. Throughout its length, the conduit would be buried with a minimum cover of h feet. At major unimproved stream crossings, the conduit would have- a., cover of 20 feet-, g and would be encased in concrete. Automatic air release valves would be installed at all high points, with automatic blowoff valves at low points where release would discharge to a stream channel. The Santa Susana Tunnel would have a horse- shoe section, 7 feet in diameter, and would be concrete lined throughout. The slope of the tunnel invert would be 0.0009, and water therein would flow under gravity at a depth of $.7 feet. The two pumping plants required on the main conduit would have identi- cal facilities. Inflow to the plants would be from a small regulating reservoir on the line, installed to maintain a constant discharge and head. Each plant would be equipped with five pumping units in parallel connection. Two of the units would have capacities of 25 second-feet, and the remaining three units would have capacities of 3>0 second-feet. One of the larger pumping units would be used for standby purposes. Each 2$ second-foot capacity unit would consist of two pumps connected in series, each equipped with a ii3>0 horsepower motor. Each of the lar- ger units would similarly be equipped with two pumps in series driven by 900 U-202 horsepower motors. The pumping lift at each of the plants would be about 225 feet. The take-off for the Oak Canyon Terminal reservoir at station mile 77 would be effected by a bifurcation structure in the main conduit. The Oak Canyon lateral would be a 42- inch diameter reinforced concrete pipe about 4,000 feet in length, and would have a capacity of 40 second-feet. Pumping Plant No. 3 would be located on the right abutment of Oak Canyon Dam described hereinafter. A maximum lift of 90 feet would be required on the lateral with Oak Canyon Terminal Reservoir full. Pumping Plant No. 3 would be equipped with two 20 second-foot capacity pumps driven by a 300 horsepower motor. Terminal Storage In order to obtain the maximum utility from the Ventura County Aque- duct and to provide the peaking capacity within Ventura County, construction of two terminal storage reservoirs was considered. ■ For illustrative purposes, reservoirs that would be required for regulation of the conduit with a capacity of 150 second-feet are described herein. A dam, and reservoir with capacity of 7,500 acre-feet, would be con- structed at the Oak Canyon site to regulate the 40 second-foot diversion from the main conduit. This water surface elevation at the spillway lip would be 1,100 feet. Water from this reservoir would be distributed in the Calleguas- Conejo Hydrologic Unit. The Oak Canyon Dam would be an earthfill structure with an impervious core and upstream and downstream sections of random fill. The dam would be 170 feet in height from stream bed to spillway lip, with upstream and downstream slopes of 2.5:1. The volume of fill would be about 1,587,000 cubic yards. The spillway would be across the right abutment, and would have a dis- charge capacity of 2,000 second-feet. Releases from the reservoir would be effected by means of a concrete outlet tower. A topographic map of the dam site was prepared at a scale of one inch equals 100 feet, with a contour interval of 10 feet, by the Division of Water Resources in 1953. Areas and capacities of 4-203 the reservoir for various stages of water surface elevation were determined from available U.S.G.S. quadrangles with a liO-foot contour interval. Cone jo Terminal Reservoir would provide terminal regulation and water service to the Oxnard Plain and Pleasant Valley Subunits and the Ventura Hydro- logic Unit. The dam would be located on Conejo Creek near the boundary between the Santa Rosa and Conejo Subunits, and would create a reservoir with storage capacity of 20,000 acre-feet. The water surface elevation at the spillway lip would be 360 feet. The dam would be an earthfill structure with an impervious core and upstream and downstream sections of random fill. The dam would be 130 feet in height from stream bed to spillway lip, with 2.5*1 upstream and down- stream slopes. The volume of fill would be about 1,655,000 cubic yards. A spillway would be across the right abutment and would have a discharge capacity of 6,000 second-feet. Releases from the reservoir would be effected by means of a concrete outlet tower. A topographic map of the dam site was prepared at a scale of one inch equals 100 feet, with a contour interval of 10 feet, by the Division of V/ater Resources in 1°53» Areas and capacities of the reservoir for various stages of water surface elevation were determined from U.S.G.S. quad- rangles with a IjO-foot contour interval. Distribution of Colorado River Water in Ventura County From the Conejo Terminal Reservoir, Colorado River water could be delivered by gravity to the Oxnard Plain and Pleasant Valley Subunits, to the City of Ventura, and to the Santa Rosa Sub unit. It was assumed that water supplies for the Conejo Subunit and for the Malibu Hydrologic Unit would be met initially from the main aqueduct. Water from the main aqueduct could also be served in the Tierra Rejada Subunit. Estimates were not made of works required for providing such service. The Oak Canyon Terminal Reservoir would be utilized to supply Colorado River water to all of the Calleguas-Conejo Hydro- logic Unit except the Santa Rosa, Tierra Rejada, and Conejo Subunits. U-20U As has been stated, the Oak Canyon Terminal Reservoir would regulate a continuous inflow of 40 second-feet of water from the Oak Canyon lateral, equal to a seasonal supply of about 29,000 acre-feet. It was estimated that reservoir evaporation losses would approximate 300 acre-feet per season, leaving about 28,700 acre-feet of water per season for use in the service area of the reservoic Because of uncertainties attendant upon the development of presently undeveloped lands in the service area, conduits from the reservoir were designed to distri- bute this seasonal supply to strategic points in each subunit. Deliveries to the East and West Las Posas and Simi Subunits would be effected through 42-inch diameter centrifugally spun reinforced concrete cylinder pipe, extending northerly from the reservoir to Los Angeles Avenue, where a wye would be located. From the wye, one lateral would extend westerly to the East and West Las Posas Subunits and the other easterly to the Simi Subunit. The Simi lateral would consist of about 27,000 lineal feet of reinforced concrete cylinder pipe, 30 inches in diameter, and would terminate in a regulating reservoir of 25 acre-feet storage capacity near Santa Susana. The Las Posas lateral would consist of 28,600 lineal feet of 42-inch diameter, 33,000 lineal feet of 36-inch diameter, 14,500 lineal feet of 30-inch diameter, 18,700 lineal feet of 18-inch diameter, and 2,400 lineal feet of 12-inch diameter reinforced concrete cylinder pipe. It would terminate in a regulating reservoir with storage capacity of 75 acre-feet. It was estimated that the Simi and Las Posas laterals would deliver seasonal supplies of 7,000 acre-feet and 21,700 acre-feet, respectively. It was assumed that lands lying above the laterals and requiring supplemental water would be served by pumping. As stated, it was assumed that Colorado River water for the Conejo Subunit and the Malibu Hydrologic Unit would be taken initially from the main Ventura County Aqueduct. To this end a bifurcation structure would be placed in the aqueduct at a point about 9,000 feet from its terminus, and releases 4-205 : would be made into a 30-inch diameter reinforced concrete cylinder pipe, 3,100 feet in length. This line would terminate in a regulatory reservoir of 80 acre- foot storage capacity northeasterly of Newbury Park. From this reservoir, a reinforced concrete cylinder pipe 36 inches in diameter and 14,100 feet in length, would extend southeasterly toward Newbury Park. At this point, a wye would be located, and laterals would extend westerly and easterly, respectively, therefrom. The westerly trending lateral would consist of 27,900 lineal feet of 18-inch diameter and 4,000 lineal feet of 12-inch diameter reinforced concrete cylinder pipe, and would terminate in a regulating reservoir having a storage capacity of 55 acre-feet. The easterly trending lateral would be about 19,400 feet in length and would terminate in a regulating reservoir of about 35 acre-feet storage capacity, located just below the saddle separating the Malibu drainage area from that of Cone jo Creek. Thus, water service could be provided therefrom to lands in the Malibu Hydrologic Unit. The lateral would be a reinforced concrete cylinder pipe including 7,000 lineal feet of 24-inch diameter pipe and 12,400 lineal feet of 18-inch diameter pipe. It was estimated that about 4,300 acre-feet and 2,900 acre-feet of water per season would be delivered from the westerly and easterly laterals, respectively. Estimates of cost were made for delivery of Colorado River water from the Cone jo Terminal Reservoir to Oxnard Reservoir, which water would then be utilized in the Oxnard Plain and Pleasant Valley Subunits as described in connection with plans for local conservation development. The conduit from Conejo Terminal Reservoir to Oxnard Reservoir would be lock joint reinforced concrete cylinder pipe, with a capacity of 150 second-feet. It would consist of about 73,200 lineal feet of 66-inch diameter pipe, and would deliver about 45,000 acre-feet of water per season to the Oxnard Plain and Pleasant Valley Subunits and 10,000 acre-feet per season to the Ventura Hydrologic Unit. It was assumed that water service for the cities of Oxnard and Port Hueneme would be provided from the well fields in Oxnard Forebay Basin as previously described. 4-206 This ground water draft could be replenished by Colorado River water if a lateral were provided from the conduit to the Saticoy spreading grounds. Service of Colorado River water to the City of Ventura and the Ventura Hydrologic Unit would be provided by a pipe line about 37,000 feet in length extending from a bifurcation structure in the conduit at Oxnard Reservoir. This line would terminate in a reservoir with storage capacity of 25 acre-feet at an elevation of IliO feet, located in the southeasterly portion of the City of Ventura. The line would consist of lock joint concrete cylinder pipe, 36 inches in diameter, and would have a capacity of 25 second-feet. It was estimated that the line would be capable of delivering about 10,000 acre-feet of water per season to the Ventura Hydrologic Unit. Pumping would be required if Colorado River water were to be utilized in the Upper Ojai, Ojai, or Upper Ventura River Subunits, and also in portions of the City of Ventura. Chlorination, and possible softening would be required for water used for industrial and domestic purposes. Estimates of Cos t Estimates of capital and annual costs for importation and distribution of Colorado River water in Ventura County are presented in this section. The estimates, while preliminary in nature, include all anticipated expenses in connection with construction and operation of the facilities considered. Scope of the studies, however, was limited to facilities for delivery of the supple- mental water supply to a strategic location in each of the four hydrologic units, and the estimates do not include costs of final distribution of water to individual users. However, the system described in connection with plans for local conservation development could be utilized for distributing Colorado River water in the Oxnard Plain Subunit. The estimates do not include costs for any required treatment of the portion of the wa-t©v- that would be used for domestic or municipal uses* U-207 Capital costs for the Ventura County Aqueduct, terminal reservoirs, and distribution system were estimated from quantities determined from preli- minary designs, and from unit prices of construction items taken from recent bid data for projects similar to those in question or from manufacturers' cost lists. Allowance was made in the estimates for acquisition of necessary lands, easements, and rights of way. It was assumed that easements would be obtained, gratis within existing public right of way. It was estimated that construction of the aqueduct would require four years, and interest on the capital cost of ' construction items at a rate of h per cent over one-half of this construction period, was included in the cost estimates. Allowances in the amount of 10 per cent of construction costs for engineering and administration, and 15 per cent for contingencies were also included. In addition, officials of the Metropolitan Water District estimated that were a conduit with capacity of 100 second-feet to be constructed for Ventura County, an additional cost of &2, 000, 000 would be required for enlargement of the proposed Lower Orange County Feeder from Lake Matthews to the Walnut Canyon take-off to accommodate the required increased capacity* Allowances in the costs estimates for increasing the size of the Lower Orange County Feeder for capacities of the Ventura County Aqueduct other than the foregoing 100 second-feet were taken as proportional to the ratio of capacities. The Metropolitan Water District of Southern California currently charges $10 per acre-foot for untreated Colorado River water. Public agencies annexing to the District are also required to pay their share of the capital costs of the Metropolitan Water District system. Annual payments beginning in the fiscal year 1929-30 are assessed for this purpose, based upon the assessed valuation of the area seeking admission. Four per cent simple interest is charged on these back taxes, and the total amount due may be paid by annual amortization payments on a h per cent interest basis over a 30-year period. In : »•■• U-208 addition to back payments, current taxes must be paid annually. For purposes of cost analysis, it was assumed that Ventura County would annex to the Metropolitan Water District during the fiscal year 1953-5U, and that the first taxes would be assessed during the f iscal year 195^-55 • From the current rate of increase in assessed valuation of the County, it was estimated that the assessed valuation therein would be ^306,000,000 in the fiscal year 1953-5k> and $329*000,000 in the fiscal year 195k-55« It was also assumed that the tax rate of the Metropolitan Water District for 1953-5U, of 0,25 per $100:of assessed valuation, would prevail in 195^-55« Based on these assumptions, it was esti- mated that back taxes, together with interest, payable by Ventura County would be about $15*570,000, vhich, if amortized over the 30-year period at k per cent, would result in annual payments of about $900,000. This includes the tax pay- ment during the first year which would be about $822,000. Presented in Table 107 is a yearly summary of back taxes and interest that would be payable by Ventura County to the Metropolitan Water District of Southern California, if annexation were made during the fiscal year 1953-5U. U-209 TABLE 107 ESTIMATED BACK TAXES AND INTEREST PAYABLE BY VENTURA COUNTY IF ANNEXED TO METROPOLITAN Y/ATER DISTRICT OF SOUTHERN CALIFORNIA BETWEEN DECEMBER 1, 1953 AND DECEMBER 1, 1951* i Tax rate i . : : : : levied j : per #100 i Interest : Fiscal : Assessed : i by Metro- . Interest I t Tax I at 1* i i Total year ! valuation \ politan i Water i District i rate : i per cent : payment 1929-30 $106,619,530 $0.01* .9991*301 3 1*2,650 4 1*2,630 i 85,2( 1930-31 108,330,350 .03 .9591*301 32,500 31,180 63,6* 1931-32 107,906,370 .03 .9191*301 32,370 29,760 62,lj 1932-33 83,367,180 .01* .8791*301 33,350 29,330 62,61* 1933-31* 76,817,1*50 .01* .8391*301 30,730 25,800 56,5; 193li-35 76,618,310 .10 .7991*301 76,620 61,250 137,8' 1935-36 82,715,200 .20 .7591*301 165,1*30 125,630 291, 0( 1936-37 85,1*50,010 .37 .7191*301 316,170 227,1*60 51*3,6; 1937-38 96,930,330 .1*0 .6791*301 387,720 263,1*30 651,1!' 1938-39 9l*,096,290 .1*0 .6391*301 376,390 21*0,680 617,0' 1939-1*0 96,512,720 .1*2 .5991*301 1*05,350 21*2,980 61*8,3: 191*0-1*1 98, 321*, 780 .1*9 .5591*301 1*81,790 269,530 751,35' 191*1-1*2 100,1*52,1*80 .1*8 .5191*301 1*82,170 250,1*50 732,6; 191*2-1*3 101*, 977, 1*10 .1*8 .1*791*301 503,890 21*1,580 71*5,1*'' 19i*3-l& 111,066,070 .1*8 .1*391*301 533,120 231*, 270 767,3!' I9kh-k$ 123, 651*, 720 .1*8 .3991*301 593,51*0 237,080 830,6:- 191*5-1*6 135,536,120 .50 .3591*301 677,680 21*3,580 921, 2< 19U6-U7 Ii*l*,5l5,l60 .1*8 .3191*301 693,670 221,580 915,2! 191*7-1*8 160,209,280 .35 .2791*301 560,730 156,680 717,1*:' 191*8-1*9 189,539,050 .31* .2391*301 61*1*,1*30 15U,300 798,7: ' 19U9-50 228, 7 21*, 090 .31* .1991*301 777,660 155,090 932,7!' 1950-51 21*1,826,230 .31 .1591*301 71*9,660 119,520 869,1* 1951-52 257,003,000 .30 .1191*301 771,010 92,080 863,0!' 1952-53 283,230,1*90 .29 .0791*301 821,370 65,21*0 886,6:- 1953-51* 306,000,000' ■ - 2 ** .0391*301 765,000 30,160 795,1< 1951*-55 329,000,000 .25 .00181*11 822,500 1,510 82l*,03 TOTJ lLS 411,777,500 v>3, 792, 780 m>15,570,26| Annual amortization payment, 30 year •s, 1* per cent . interest ti900,l*C * Es timated 1*-210 Estimates of annual costs also included interest on and amortization <' the capital investment, and electrical power charges for pumping. The charges :>r electrical energy were in accordance with schedual PAP-2 of the Southern (ilifomia Edison Company, which was effective on September 1, 1946. Presented in Table 108 is a summary of the estimated costs of the pro- ved Ventura County Aqueduct with five alternative discharge capacities. Costs iown in Table 108 do not include costs of distrubuting Colorado River water com the terminal reservoirs to strategic points within the county. Such costs [pre only estimated for a Ventura County Aqueduct with discharge capacity of 150 scond-feet. Estimates of initial capital and annual distribution costs for this ize of aqueduct are summarized in Table 109. U-211 QO O H 3 B o o 8 tf\ H to o H c o CO cd • • t« CD CO * U -p CD O a> Pj o 0) » cm T) 0) r> C «H O 1 O CD CD U CO O CTJ t • •• •s.g •» +> .' o o fe o a d m o -r> & O • ci> p. » £ ■P •h -d O CD o ct) U o a, cd O o 05 > in • O «H o H en CD T3 T3 C «• • ■ cd o o m o cm a § +3 M o o o o "ogo o o o o o Q o o o O D- I £3 I vO o o o »\ SO vO o CV2 «%: 8 o 8 o o o o o to o H o -p CO o o CD CO cd o o o o o 8 8 8 •S #\ *\ ^ o o en o to O CM ^O O O to H •» «\ rH CM O O O Q Q O O O o o o o •\ «fc % »\ O Q m O CM O CM O M>tOvO to O m sO H c"> u-\\0 H 8 cno sO o -4- H cd o en cm -4 O CM to m o to -3" •-^ O O O Q 8888 •» n •* *\ o q en en vO O CM CM eno to cm O in en O f- o en en o o 88 cm m CM CM en cm o o o o o o o o o o o o o o o O O Q o o o 8 o ^ #\ *\ ^ o o en^o to O CM O H O to O e> -P CO CD O •P £ O CD CD u 6^ § U p to b0 a CD •H -P C CD T3" CD C CD 3 H ^-P -P •H CD a a d 2* rd cd .1 CD CT* cd W5 05 £ -P O CD -3 p >s >j-p -p 03 -d •H cd .p -p u G CO a Cm 6 CD O CD cd CD 2 ° - c w -p +3 Cd Cd <» 2 -H -p CO 3 CD TJ 2?S S B c §) c O -P ^ fi -p c o -p ^ CO +S CO X O -H c cd O O O CD p •H cQ Eh •H «H cd -p -P fi si C >,& >» O ^_3 CO (0 Q O -P d -P Cd 1 o o (D ed C C fc c^ O P O O O (U w o 8 o CT\ to in in to o O H k-212 TABLE 109 SUMMARY OF ESTIMATED INITIAL COSTS OF DISTRIBUTING COLORADO RIVER WATER WITHIN VENTURA COUNTY, WITH VENTURA COUNTY AQUEDUCT OF 150 SECOND-FOOT CAPACITY Estimated Costs Item : Capital !■ Annual C alleguas - Cone j Distribution System $ h, 800, 000 $ 257,000 Oxnard- City of Ventura Conduit 5,868,000 311,000 Oxnard Plain-Pleasant Valley Distribution System 3,038,000 169,000 TOTALS $ 13,706,000 I 737,000 U-213 Discussion of Alternative Initial Plans for Vfater Supply Development Presented in this section is a discussion of possible alternative initial plans for water supply development in Ventura County, as related to their accomplishments, and to their feasibility for immediate construction, financing, and operation by local interests. It has been shown that immediate sources of supplemental water include local conservation developments, both surface and underground, and the Colorado River through facilities of the Met- ropolitan Water District of Southern California, In the future, a water supply sufficient to satisfy the portion of forecast ultimate requirements in excess of the probable maximum supply that could be developed locally in the County, will be available from the Feather River Project. Supplemental water available from this project should not be considered as competitive or substitutional to either potential local conser- vation developments or to the imported supply that might be obtained from the Metropolitan Water District. The cost of supplemental water from the Feather River Project, which on the basis of preliminary designs and financial analyses was estimated in 19^1 to be $$0 an acre-foot delivered to southern California, might be used as a guide in establishing the limit to which water resources of Ventura County should be developed. However, this should not be taken as a rigid criterion for limiting local development. Provision for a supplemental water supply for Ventura County is a matter of immediate concern, whereas the timing of financing and constructing the Feather River Project is as yet unde- termined. The selection of an initial plan of water resources development for Ventura County and of the component features thereof was based on consideration of the following factors: (l) Present and forecast future supplemental water requirements of the County; (2) the amount of new water that would be developed under a given plan or feature thereof, relative to that under alternative plans; 11-211* 3) the capital cost of a given plan relative to that of alternative plans; (U) ,he annual cost of net safe yield that would be developed under a given plan •elative to that under alternative plans; (5) the annual cost of incremental iet safe yield that would be developed from various sizes of a given plan or omponent feature thereof; and (6) the limit of bonding capacity of the County 'or water resources development. In regard to the latter factor, it has been estimated that the present onding capacity of Ventura County for financing water resources development oes not exceed $50,000,000. From a practical standpoint^ it may be that bonds n this amount could not be marketed at reasonable interest rates. This latter onsideration is therefore an important factor in selecting an initial plan for he development of the water resources of the County. There is presented in Appendix D a discussion of organizational and inancial aspects attendant upon plans for providing supplemental water for entura County. As described in this appendix, it appears that under the ex- sting political structure in the County, the Ventura Hydro logic Unit is the nly unit with the financial capacity to develop supplemental water in an amount nfficient to satisfy its present water supply deficiency. It is believed that ily through the formation of a single county-wide water agency, organized with ppropriate powers, can a sound comprehensive program of water resources devel- Dment be financed. It is considered that such an agency is necessary not only d undertake the development of local water resources, but also to obtain im- srted water from either the Colorado River Aqueduct or the Feather River Pro- SCt. Were such a county-wide water district to be formed in Ventura County, is function would be to finance, construct, and operate major projects, and to cecute water service contracts with subordinate districts. The existing Ven- lra Municipal Water District, and United Water Conservation District, with U-215 possible modification of the powers of the latter agency, could convey and dis- tribute water within their respective areas. A similar district would necessar- ily have to be formed in the Calleguas-Conejo and Malibu Hydrologic Units. In some areas of the County, distribution of water to individual users might be undertaken by improvement districts which would be formed for this purpose. A direct benefit would inure to all of Ventura County through the formation of a county-wide water district, as a result of broadening of the tax base of the constructing agency, and corresponding enhancement of the financial capacity thereof. With a broader tax base, it would appear that more favorable interest rates could be obtained on bond issues for water resources development. Furthermore, increased flexibility in utilization of developed water supplies would be possible as the needs of the various hydrologic units demanded. In the Ventura Hydrologic Unit, it is indicated that supplemental water in excess of the immediate requirements could feasibly be developed. From an engineering standpoint, it has been demonstrated that it would be possible to divert a por- tion of this surplus for interim use in the Oxnard Plain Subunit. With construc- tion of a reservoir at the Casitas site by a county-wide agency, this surplus could be temporarily contracted and sold to users in the water deficient coastal plain of the Santa Clara River Valley, thereby relieving tax payers of the Ven- tura Hydrologic Unit of the burden of paying for water not presently needed. It has been demonstrated that costs of water available to Ventura County through the construction of potential surface storage developments, or by importation through facilities of the Metropolitan Water District of South- ern California are quite expensive, both in capital cost of construction of re- quired works and in unit cost of water made available. It has also been shown that the least expensive source of supplemental water available to Ventura Coun- ty is extant in presently undeveloped ground water storage, but that development U-216 f this source is limited by possible interference with the rights of overlying round water users. Surface storage developments considered varied in capital cost from bout $U,000,000 to $UU,000,000, with developed net safe yields varying from a dnimura of about 2,500 acre-feet per season to about 27*000 acre-feet per sea- ion. Average annual unit cost of net safe yield varied from a minimum of about 30 per acre-foot to in excess of $15>0 per acre-foot at the reservoir. The more easible of the developments studied would vary in capital cost from about 18,000,000 to about $15,000,000, with net safe yields varying from about 12,000 ;o 22,000 acre-feet per season. Average annual unit cost of net safe yield that rould be made available by construction of the more favorable developments ranged rom $30 to $50 per acre-foot. For comparative purposes, there is presented in Table 110 a recapi- iulation of yields of water that would be developed by construction of the sev- eral storage capacities considered at each of the ten dam and reservoir sites studied in Ventura County. Presented in Table 111 is an economic comparison if potential Ventura County reservoirs. The estimated costs are based on an issumed h per cent interest rate. The estimates do not include costs of dis- iribution facilities, and the unit costs of new water shown are indicative of luch costs at the reservoirs. Certain of the relationships shown in Table 111 tre depicted graphically on Plates 35, 36, and 37. h-217 - CO CC o :> cc LU co LU CC ID o o o — C »- X CO o c X o o c o CO >. — CO -f- X) Jj (0 (0 H> 1. — o Q co u. o >

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CO 00 CM — CM — < -3" Jt — • J-O CM LA LA r— 00 ON O OOO ooo o ooo ooo LA O O -3- vO O O OOO ooo ooo o o o o o o OOO ooo ooo O o o o o o o o o o o o o o o ooo ooo ooo ^ *■ •. iNJ i — CM -~r-o on KN.00 CM vO O LAOO IA CO » oo ^A •vO — 1 vO IVNsO CO oooo OOO oooo OOO O O OOO OOOO ooo oooo OOO O O OOO OOOO ooo oooo OOO O O OOO * *l •* ** •« •» •* * ■» •* ^ CM LAO >0 CM .-t -3- LAtAf^O O LAO LAO J- 00 00 CTv O N~\LA -.c\iir\ lAJNO LAI~- O CM LA \f> ON_3- Si O O OOO OOO 8 O OOO OOO O ooo ooo •t «k * O O ooo O LAO LA LA O LALA LAIN-O J- — k. -1- 1 CO MM — T3 w O JC3 C CU^' o > k. cu o — CU v. CO CU ~0 CO CJ CO CO 0) -t- -V- cu (D-OO ■*- CO o o O CO CM u_ >vCJ o c_> * u o CO ^^ CI) 7) [0 a tx "a i a i- *- u c u. id LO on c ^ - CU »- cu a k- iA v-o cu — a o to o cu co Q. O +- CO a o CL) £ E B X o a. c o u •t- >* D c r _^ — 10 CU CO o c_> cu Q. V. v- •— 4 o cu cu • «■» Q. _J > D Q. —J cu »- r> CQ o to o o > k. t3 a: 5T CO k- O CO ■— ^ — OJ o c o CO u +• i c. (O i\} CO CO oil Ci_ cu ■—* m iq 4> u k- o (0 •+- +- J c -L) o k_ co +- k. 4> c > o ■5 CO k. 4- • — O o CJ > u_ k. 1 4) ■o V) • r CO Efl o u o 4) cu u_ > 10 O 01 o en oo a u 41 -<_ 4) +- to ■ ^ >• 3 y J3 Ii-219 As shown on Table 110, for reservoirs on tributaries of the Santa Clara River, new water that would be made available to the Oxnard Forebay, Ox- nard Plain, and Pleasant Valley Subunits, if the reservoirs were operated under the uniform release method and the water was conveyed to the three subunits by surface conduit, would substantially exceed new water made available thereto un- der the rapid release method of operation. Therefore, further consideration was not given the rapid release method of operation, and all yields of water here- inafter referred to in connection with these reservoirs are those that would re- sult with uniform release operation. Presented previously in this chapter was a discussion of possible annexation of Ventura County to the Metropolitan Water District of Southern California, together with estimates of cost of constructing various capacities of aqueduct to connect with the Metropolitan Water District system, and annual costs that would result from such annexation and construction. It was shown that for the capacities of aqueduct considered, capital costs, including the costs of terminal regulation in Ventura County, varied from about $20,000,000 to about $5U,000,000. The average annual unit cost of water delivered to Ven- tura County varied from about $170 per acre-foot for the smallest capacity aque- duct, to about $58 per acre-foot for the largest capacity considered. These costs may be compared with values presented in Table 111. It may be noted that for the four more favorable local reservoirs in Ventura County, average annual costs per acre-foot of net safe yield are substantially less than similar costs of Colorado River water delivered to Ventura County, for all capacities of aqueduct considered. Although the unit cost of delivered Colorado River water shows a marked decrease with increase in aqueduct capacity, there is also a substantial increase in required capital expenditure. It is believed that if Ventura County were to annex to the Metropol- itan Water District of Southern California, sufficient aqueduct capacity should U-220 be constructed initially to eliminate present water resources problems and to provide for future growth of the County This follows from the fact that the aqueduct does not appear to be susceptible to staged development. To achieve this objective, an aqueduct with capacity of at least l!i>0 second- feet should be constructed. The indicated capital cost of constructing such an aqueduct is about ft £U, 000, 000. Aqueducts of lesser capacity would provide insufficient supplemental water at a relatively high capital outlay. Also, as stated, the average annual unit cost of water so delivered does not compare favorably with that of potential local conservation developments. From examination of Tables 110 and 111, and of Plates 35, 36, and 37, it is indicated that of the potential surface storage developments studied in Ventura County, the Casitas site on Coyote Creek, the Cold Spring and Topatopa sites on Sespe Creek, and the Devil Canyon and Santa Felicia sites on Piru Creek are the most favorable from the standpoint of capital cost, amount of net safe yield developed, and average annual unit cost per acre-foot of net safe yield. The remainder of the sites considered, although favorable in some respects, and possibly worthy of consideration in the future, were not given further con- sideration for initial development. Of the four sizes of reservoir considered at the Casitas site, it may be noted that a definite increase in yield persists as reservoir capacity is en- larged, but that the average annual unit cost of the 21,900 acre-feet of net safe yield that would be developed by the 156,000 acre- foot reservoir would be about $49 per acre-foot, or substantially in excess of the comparable costs of yield developed by the smaller sizes of reservoir. Furthermore, the average annual 4-221 cost per acre-foot of incremental yield between the 130,000 and 156,000 acre-foot reservoirs was estimated to be about $121 per acre-foot. Between the reservoirs of 105,000 and 130,000 acre-foot storage capacity the estimated average annual unit cost of incremental yield was only $96 per acre-foot. For these reasons, it was concluded that the most desirable capacity of reservoir at the Casitas site would be about 130,000 acre-feet. Estimates of cost of yield for various capacities of Cold Spring Reser- voir indicate that this site is suitable for the construction of a dam and reser- voir with a storage capacity of 100,000 acre-feet, and that the site is the most favorable of those studied on Sespe Creek. A reservoir of this capacity at the Cold Spring site would be the least expensive to construct, and have the lowest annual cost per acre-foot of net safe yield developed. As was stated in earlier discussion of this reservoir, there are uncertainties regarding runoff at the dam site. Based on available hydrographic data, and upon rough estimates of run- off for the period from 1894-95 through 1950-51, an analysis was made of the probable time required to fill Cold Spring Reservoir after its construction. It was estimated that for the 100,000 acre-foot reservoir, about 16 years on the average would have been required for the reservoir to fill after construction. Thus, it is indicated, on the basis of the sparse hydrographic data available, that 100,000 acre-feet of storage capacity at the Cold Spring site probably ap- proaches the absolute maximum which should be constructed. In order to protect the site against either underdevelopment or construction of excess capacity, it was concluded that construction of a Cold Spring Reservoir should be postponed until such time as adequate hydrographic data become available. Analysis was made of the Topatopa, Santa Felicia, and Devil Canyon sites, which as stated appear to be favorable for initial construction, to as- certain the most feasible storage capacity at each of the sites under a plan of coordinated operation. In this connection, it should be emphasized that con- struction of a reservoir at the Santa Felicia site would preclude subsequent construction of a reservoir at the Devil Canyon site. Conversely, if a reservoi 4-222 were to be constructed at the Devil Canyon site this would eliminate the possi- bility of building a dam at the Santa Felicia site. In Table 111 it is. shown that for a reservoir storage capacity of 100,000 acre-feet, the Santa Felicia site is more favorable than the Devil Canyon site from the standpoints of both capital cost and annual cost per acre-foot of net safe yield, and that in these respects it is also more favorable than a comparable capacity at the Topatopa site on Sespe Creek. As has been stated, construction of reservoir capacity at the Santa Felicia site is limited to a maximum of about 100,000 acre-feet, while at the Devil Canyon site a dam creating storage capacities up to about 150,000 acre-feet is considered feasible. The Topatopa site also is considered limited ,to a maximum storage capacity of about 100,000 acre-feet. There is presented in Table 112 an economic comparison of selected com- binations of reservoir storage capacities at the Santa Felicia, Topatopa, and Devil Canyon sites. The estimated costs are based on an assumed 4 T er cent in- terest rate. It may be noted that this analysis was made under the- assumption that the reservoirs would be operated coordinately under the uniform release method. Values are presented showing the accomplishments of various combinations of reservoir storage capacity at the three sites, operated both with releases for maintenance of ground water levels and without such releases. It will be noted that for any given combination of reservoir capacity, not only would the greatest yields be obtained without releases for maintenance of ground water levels, but also the average annual cost per acre-foot of net safe yield would be substan- tially less without such releases. It is also shown in Table 112 that the largest yields of water with the lowest annual unit costs are obtained with a Devil Canyon Reservoir of storage capacity of 150,000 acre-feet operated for the joint benefit of the Santa Clara River and Calleguas-Conejo Hydrologic Units. 4-223 si < oc 5 OC uu z to o UI ^ OC H- _» ce «* UJ —• o. I- o Z UJ UJ ►- c/l o u, x o •— Q. z O Q to z —1 \sz m co w. co ■»- on k- (0 u- ■ — co c o o .. o 11 n O CO — • CO 1 D CO c >- in (0 3 co S B -C CO c o — -t- co co k. ■ — co ■•- on w 4) 1. -3 CO c CO 01 CO CO Q. — t — u_ +- CO CO O CO k. k- e a co .. .. > <£ , (0 -»- o »— k. " " m o CO — « u. yo m c c > to co 3 co X) +- D 0) s co c o — • (/) CO k. > £ CO -»- O/l k. CO c <0 J: _ — u_ -t- O CO CO O CO -t- o k. 00 o o co — • tw u. O "O CO 1 0) £ C > W (5 3 4) k- -C JJCO- to o -f- io o k, +- eg ■«■ co +- on k. Q k. o tn om- CO o CO CO — <_> (0 +• O i- O CO k_ o on+- a. CO U. CO CD CL o •• •• CO ■♦- o h- Z " " In T? o to — U_ CJ "O cu U c Q ? » x: (/) CO k. ■»- +■ co +- on k. — • co — CO c CO (0 CO 3t — « — • ii_ +- c <»- co ro o co O 1 k- e 3 CO CO •• CO k- k. (0 co u o co — • co co 3 co j_ -— _C CO c o — CO +- i/l CO k. en — CO -t- O/l k- JS co c co u CO CO O vD z k- e a • • •• *4 ♦ • •• M •• ^ +- CD -»- 3 o CO i— Q- CO CO c o/i-t- -H C 10 CO — >» k. CO > c O u_ CO CO ■+- 1 O C-> CO CO k_ ** >- u ro — CO Q. o o > c -t- w - — ra CO a t— w. " «••>•»»* in CO m co — o ■<- o t_ c — 13 CO — • IT) CO U. ^O nO LA KMCMOl C0O^><) K-\ K\rCk«\ c\it\j-i vo'*-ao — • j- oo »r» it\ rr\ — O O O O O O O O O O O Q on— < — • lt>iv_ r~- ^r^— . — o^-' N - f- CM Lf> -3-00 — • CM — • CTN CM O On CM LA J- 00 — « 00 O C3>-0 r^ 00 00 r^- ^ s^ r»- n* r«- ■<&■ o o o o o o o o o o o o o o J*vO vO -& JTO ^O ^T — — |n- CM LT> — O 00 KMftOO O O LT\00 vO ^O -3- CM ON— • O O -3- ON j- lt\oo— tr\ r- o oo 00 00 On fN* ^^ f^- ^ vOrrv— NOIA nOOL/n. o— «on oo-^cM oo^r— t OOOOf- OOONON ONO — • r~ LT< J3-LTN 1^- 00 00 -=f J- -3- O O O O O O O CM CM o r«-r»- KMnq -3- CM — • OCM3 ON 00 r- (^- r^ fN. |n- O U~\ O N~\(M ON ON ON NMC\-. CM CM CM l>- O — « — ■ 1^- K"\ K\ -3- -3- LTM/NsO j- j- -3-tr\ CM CM CM CM o o o o o o r~ t^- in- O O O o o o KMAIO o o o o o o LTkLfM/N O O O O o o o o LA LALTNl/N o o o pop fN. 1 — r— CM ONK"\ I s - J- 00 LOLfN— « CM CM — • 25,961, 20,958, 17,572, 22,671, 19,61*8, 16,282, O O <" 1 KN. (AO -3 O O O vO — < — • CO -ST fr\ rr\ CM CM O IOIN vO nO CM CM CM CM o o o o o o O O -3" LfN-^ ^~- NNifTkCM 50,800 26,800 22,500 o o o o o o -3- KN.ON vO CM I s - CM CM ~ O O O O O O O O LCN — < LT\ O CM _3-0NvO 3L^^MO 55,ooo 51,500 27,500 o o o o o o LTMfNO o o o o o o o o o o o o o o o O ONnO o o o o o o o o UN ONO O o o o o o o UN LAO Q no tr\ tC\(\l CM r-IACjN CM IM — • K\C0 St C\J — — « UN, jJ-K\K\ O vO TV. iO>CM CM o o o o o o o o o o o o o 000 o o o o o o o o o o o o o 000 o o o o o o o o o o o o o 000 k. •. «^ «.->•. ^ » •. O UNO LAO LA O LAO O O UNO O LAO O n- W\ r*- un cm UN CM O i/\u\r\JO ONlA CM -^ — 150,000 2 150,000* 2 150,000 2 150,000 2 100,000 2 100,000 1 100,000 1 O O O o o o O O O p 0000 000 O O O o o o O o o 000 O O O o o o o o o 0000 000 •* *. k •* » »v ^ ^ «* ■* O LAO Q UNO O r^ ia O UNO O O UN O O O F- UN O LAO OMA O^LTC O f^LA "~* ~^ ^^ "^ ■" * "■* O O o O O O o o o o o o o o o o o o o o o o o o o o o «. •■ "s * *. * o o o UN UN LA r— F- I — o o o o o o LA LA LA CO c o (_) t (0 an co co o o o a x CO CO o c in •o 0) co c l/l l« (/) a. CO CO i • T5 3 O w 1 — k. 0. CO O >~ +- CO m in CO J3 to an c +■ k. 5 -0 u. 1 ■»- X3 ■ — c s u a; 10 • — (JO m JZ k. -t--o U-22U It is shown in Table 112 that under the indicated plans of coordinated operation for the sole benefit of the Santa Clara River Hydrologic Unit, slightly lower unit costs of developed yield would be obtained with either Devil Canyon or Santa Felicia Reservoirs constructed to the indicated maximum capacity, and with Topatopa Reservoir constructed to a capacity of 50,000 acre-feet. However, there would be but a slight increase in unit cost of net safe yield with maximum storage capacity at Topatopa and with maximum storage capacity at either Santa Felicia or Devil Canyon. Because of the general paucity of feasible dam sites in Ventura County, it is believed that the more favorable sites should be developed to the maximum practicable capacity in consonance with engineering and economic criteria. It was concluded, therefore, that any dam constructed at the Topatopa site should provide a reservoir storage capacity of about 100,000 acre-feet, and that storage capacity constructed at the Santa Felicia or Devil Canyon sites should not be less than about 100,000 or 150,000 acre-feet, respectively, de- pending upon the site developed. There follows a discussion of three alternative basic plans con- sidered feasible for initial construction and operation by an appropriate :ounty-wide water agency in Ventura County. There are also presented three additional plans, that would achieve similar accomplishments in terms of water yield, but at a lesser cost through planned operation of ground water storage in the Santa Clara River Hydrologic Unit. The estimated costs of new water cited ire based on an assumed 4 per cent interest rate. 3 lan I Under the provisions of this plan relating to the Ventura Hydrologic Jnit, Casitas Reservoir would be constructed to a storage capacity of 130,000 icre-feet, together with a distribution system to serve each subunit . The capacity of the distribution system would be about 13,400 acre-feet per season. j[t was assumed that a seasonal supply of 1,400 acre-feet would be delivered to 4-225 the Ojai Subunit from Matilija Reservoir through the existing line. Under Plan I in the Santa Clara Paver Hydrologic Unit, both Santa Felicia and Topatopa Reservoirs would be constructed, each with a storage capacity of 100,000 acre-feet. The Santa Clara River Conduit would be con- structed, and would have a capacity at its terminus at Oxnard Reservoir of 120 second-feet. A distribution system to supply about 30,000 acre-feet of agri- cultural water per season and about 10,000 acre-feet of municipal water per seasc to the Oxnard Plain and Pleasant Valley Subunit s would be included in the plan. The Cas it as -Oxnard Plain Diversion Conduit would be constructed with a capacity of 25 second-feet, and would deliver a seasonal supply of about 10,000 acre-feet to Oxnard Reservoir. Under Plan I, initially about 8,600 acre-feet per season of supplements water would be made available at strategic points in the Ventura Hydrologic Unit, at an estimated average annual cost of $62 per acre-foot. About 40,000 acre -feet of supplemental water per season would be delivered to users in the Oxnard Plain and Pleasant Valley Subunit s, at an estimated average annual unit cost of $58 pei acre-foot. The total net safe seasonal yield developed by features of the plan would be about 49,000 acre-feet, with an estimated average annual unit cost of $i per acre-foot delivered to users in the Oxnard Plain and Pleasant Valley Subunits and to strategic points in the Ventura Hydrologic Unit. The estimated capital cost of Plan I would be about $52,000,000. Plan IA Plan IA would include the same component features as Plan I, except that in lieu of 100,000 acre-feet of reservoir storage capacity at the Topatopa ■ site, a well field would be constructed in Fillmore Basin and operated to yield an average supply of new water to the Oxnard Forebay Subunit of about 16,000 acre-feet per season. In addition, Santa Felicia Reservoir would be operated 4-226 >n the uniform release basis without effecting releases to maintain historic ;round water levels in Piru, Fillmore, and Santa Paula Basins. Under provisions >f this plan, an average seasonal supplemental supply of about 45,000 acre-feet )f water would be delivered to Oxnard Reservoir from developments in the Santa llara River watershed and from Casitas Reservoir. The estimated capital cost of J lan IA would be about $36,000,000. The estimated average annual unit cost of lew water delivered to users in the Oxnard Plain and Pleasant Valley Subunits rould be $34 per acre-foot. The total seasonal yield of new water developed by "eatures of the plan would be about 54,000 acre-feet. The estimated average innual unit cost of net safe yield so developed would be about $39 per acre-foot. 'Ian II Component features of Plan II would be the same as Plan I, except ,hat in lieu of 100,000 acre-feet of reservoir storage capacity at the Santa 'elicia site, Devil Canyon Reservoir would be constructed to a storage capacity f 150,000 acre- feet, and would be operated for the benefit of the Santa Clara iver Hydrologic Unit alone, under the uniform release method of operation nd with releases to maintain historic ground water levels in Piru, Fillmore, nd Santa Paula Basins. The yield of new water in the Ventura Hydrologic Unit nd the average annual unit cost thereof would be the same as in the preceding Iternative plans. In the Santa Clara River Hydrologic Unit, about 47,500 cre-feet per season of new water would be made available in the Oxnard Plain nd Pleasant Valley Subunits, at an estimated average annual unit cost of 56 per acre-foot. The total new water supply that would be developed under he provisions of Plan II would be about 56,000 acre-feet per season, having n estimated average annual unit cost of $57 per acre-foot. The estimated apital cost of Plan II would be about $59,000,000. U-227 Plan HA Plan HA includes the same features as Plan II, except that in lieu of a 100,000 acre-foot reservoir at the Topatopa site, new water in the amount < about 16,000 acre-feet per season would be extracted from the well field in Fillmore Basin, and conveyed to the Oxnard Plain and Pleasant Valley Subunits for use therein. In the Ventura Hydrologic Unit the amount of new water developed, and the average annual unit cost thereof would be the same as in the preceding alternative. In the Santa Clara Paver Hydrologic Unit, about 53,000 acre-feet pe season of new water would be made available to the Oxnard Plain and Pleasant Valley Subunits, at an estimated average annual unit cost of $35 per acre-foot. The total new water supply developed by Plan HA would be about 62,000 acre -feet per season, at an estimated average annual unit cost of $39 per acre-foot. The estimated capital cost of Plan HA would he about $43,000,000. Plan III Plan III includes the same component features as Plan II, except that Devil Canyon Reservoir would be operated for the joint benefit of the Santa Clara River and Calleguas-Conejo Hydrologic Units, and the Piru-Las Posas Conduit would be constructed with a capacity of 80 second-feet and would deliver water from Devil Canyon Reservoir to the Happy Camp Canyon and Dry Canyon spreading grounds in the East Las Posas and Simi Subunits, respectively. Releases from Devil Canyon and Topatopa Reservoirs to the Santa Clara River Conduit would be under the uniform release method of operation, with releases for maintenance of histori ground water levels in Piru, Fillmore, and Santa Paula Basins. Under the provisions of Plan III, the amount of new water and the aver- age unit cost thereof in the Ventura Hydrologic Unit would be the same as in the preceding alternative. About 39,000 acre-feet per season of new water would be developed for use in the Oxnard Plain and Pleasant VaHey Subunits, at an esti- mated average annual unit cost of $56 per acre-foot . Similarly, an average 4-228 seasonal new water supply of about 20,000 acre-feet would be delivered to the Calleguas-Conejo Hydrologic Unit at the foregoing spreading grounds, at an esti- mated average annual unit cost of $48 per acre-foot. The total new water supply- developed under the provisions of Plan III would be about 67,000 acre-feet per season, at an estimated average annual unit cost of $54 per acre-foot. The estimated capital cost of Plan Illwould be about $68,000,000. Plan IIIA The features of Plan IIIA would be the same as those in Plan III, except that in lieu of a 100,000 acre-feet reservoir at the Topatopa site, jnew water in the amount of about 16,000 acre-feet per season would be extracted from the well field in Fillmore Basin and conveyed to the Oxnard Plain and Pleaant Valley Subunits, for use therein. In addition, Devil Canyon Reservoir would be operated under the uniform release method, without releases to maintain historic ground water levels in Piru, Fillmore, and Santa Paula Basins. In the Ventura Hydrologic Unit , the amount of new water and average annual unit cost thereof would be the same as in the preceding alternative. A new water supply of about 44,000 acre-feet per season would be delivered for use in the Oxnard Plain and Pleasant Valley Subunits, at an estimated average annual unit cost of $33 per acre-foot. As under provisions of Plan III, about 20,000 acre-feet of new water per season would be delivered to the Happy Camp Canyon and Dry Canyon spreading grounds in the Calleguas-Conejo Hydrologic Unit, at an estimated annual unit cost of $45 per acre-foot. The total new water supply that would be developed under the provisions of Plan IIIA would be about 73,000 acre- feet per season, at an estimated average annual unit cost of about $40 per acre- foot. The estimated capital cost of Plan IIIA would be about $52,000,000. Comparison of Alternative Plans There is presented in Table 113 a summary comparison of estimated costs k-229 and yields of water that would result under alternative Plans I, II, and III. Presented in Table 114 is a summary comparison of cost and yields of water that would result under the provision of Plan IA, IIA, and IIIA. It is apparent from examination of these tables that with planned operation of ground water storage both capital and annual costs of plans with similar accomplishments in water yield would be substantially reduced. Because of uncertainties regarding interest rates that could be obtains in financing of the foregoing alternative plans, there is presented in Table 115 a comparison of costs that would result with interest rates of 3 per cent, 4 per cent, and 5 per cent. 4-230 to a _j D. Z 15 Ql O o ae a P ^: LU X Z 2 or <£ LU _J > 0_ — J CC 5« 25 »— _» >-• <_> LU I— *(— _J Ui LU lu < a cc o 5£ &a: -D LU LO I— cc * LU I— O < 2 O cc cc o o to LU *- l/) CD O x-ir o CO k. CI) IT) > 3 4 C (■■ 10 a. u o o — CD u-_ C *- (U — ' - OJ u- IT) 0) (5 C »«4_ CO O T3 I 10 — • CD +- CO 4) k» a> a> — o 2: c/> >» (o ro •+- +- — co a o ro o u co a> o un o (O i- — i a> ro > D +- B 4J i. cd . 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Survey to be tied into U.S.G.S. surveys. Contour at an elevation of approximately 200' above stream-bed at dam site, to be located and mapped in order to check new U.S.G.S. sheet of this area. Locate all cultures in dam and reservoir site and estimate cost of acquisition of lands. Calculate height, capacity and surface area curves for reservoir using new U.S.G.S. sheet. Obtain permissions to enter on lands for purpose of drilling holes or seismic work. (c) United Water Conservation District If this site is found feasible geologically, make preliminary designs and cost estimates for several heights of dam. 2. Hammel Site (a) State Make geological investigation of dam site. In- vestigate availability of materials. (b) Ventura County Flood Control District Provide topographic maps of reservoir and dam sites. Make estimate of cost of acquisition of lands and right of way. A-13 (c) United Water Conservation District Make preliminary designs and cost estimates for several heights of dams. 3. Topa Topa Site (a) State Investigate geology and availability of materials. (b) Ventura County Flood Control District Make estimate of cost of acquisition of lands and/or right of way. (c) United Hater Conservation District Make preliminary designs and cost estimates for several heights of dam. k» Cold Spring Site (a) State Investigate geology and availability of materials. (b) Ventura County Flood Control District Make estimate of cost of acquisition and right of way. (c) United Water Conservation District Make preliminary designs and estimates of cost for several heights of dam. b. Piru Creek 1. Devil Canyon Site (a) State Investigate geology and availability of materials. (b) Ventura County Flood Control District Provide maps of reservoir and dam site. Make esti- mate of cost of acquisition of lands and right of way. A-U* (c) United Water Conservation District Make preliminary designs and estimates of cost for several heights of dam, c. Santa Paula Creek 1. Ferndale site (a) State Make estimate of flood control benefits. Make estimate of conservation benefits. Investigate geology and availability of materials. (b) Ventura County Flood Control District Make topographic survey and map of dam site, scale 1" = 100', contour interval 5*, "to a height of 300' above stream-bed. The new U.S.G.S. sheet will be used to calculate a height, capacity and surface area curve for this dam. Make estimate of cost of acquisi- tion of lands and right of way. (c) United Water Conservation District Make preliminary designs and estimates of costs for several heights of dam. As soon as the most satisfactory dam site or dam sites are decided upon in the Santa Clara River Basin, United Water Conservation District will proceed with detailed investigation of said sites. Such investigation, if paid for with funds advanced by the Ventura County Flood Control District, shall be sufficiently broad to cover the needs of the county-wide investiga- tion. All work outlined herein to be done by the State of California and by the Ventura County Flood Control District is to be paid from funds to be A-15 made available under the aforementioned cooperative agreement between the State Water Resources Board, the Ventura County Flood Control and the State Engineer. V/ork to be done by United Water Conservation District will be paid for from funds provided by that agency. April 23, 1951 /s/ A. D. Edmonston A. D. Edmonston, State Engineer April 2h, 1951 /s/ Robert L. Ryan Robert L. Ryan, County Surveyor Ventura County April 23, 1951 /s/ Julian Hinds Julian Hinds, Consulting Engineer United Water Conservation District A-16 MEMORANDUM OF UNDERSTANDING With Reference to Water Resources Investigation of Ventura County A memorandum of understanding was entered into on April 23 and 2U, 195l> between representatives of the State Division of Water Resources, the Ventura County Flood Control District, and the United Water Conservation District, with the objective of coordinating the work of the three agencies in the investigation and study of the water problems of Ventura County. The Memorandum set forth the part of the coordinated program each agency would perform in the investigation and the cooperation that would be effected in the exchange of data so that there would be a minimum of duplication of effort and so that completion of the xvork would be effected as expeditiously as possible. Such coordination has been effectively carried out. A meeting of the representatives of the foregoing three agencies was held in the office of the State Engineer on September 29 and 30, 1952, for the purpose of reviewing the results so far accomplished by the three agencies and to program certain further work to be done. At the conclusion of said meeting it was mutually agreed that both the United Water Conserva- tion District and the State Division of Water Resources would: 1. Prepare independent cost estimates for concrete arch dams at the Topa Topa site on Sespe Creek to create gross storage of water in the amounts of 50,000 acre-feet, 75,000 acre-feet, and 100,000 acre-feet respectively. 2. Review existing yield studies for reservoirs created by the foregoing sizes of dams on the Topa Topa site on Sespe Creek. 3. Review existing yield studies for a reservoir of 100,000 acre-foot storage capacity at the Santa Felicia site on Piru Creek. A-17 Said work to be accomplished by October 15, 1952, the results thereof to be submitted to the other parties to this agreement on or about that date, and a further meeting between the parties to be held in Santa Paula on October 2Uj 1952. It was also mutually agreed, based on preliminary information available, that a rolled earth-fill type of dam is suitable and appropriate for the Santa Felicia site on Piru Creek, and that the capacity of Santa Felicia Reservoir should be limited to a maximum storage capacity of about 100,000 acre-feet in order to preserve from inundation the upstream Blue Point Dam and Reservoir site and to permit future development of said Blue Point site. It was further mutually agreed that any dam constructed at the Topa Topa site on Sespe Creek should preferably be built initially to the maximum practicable size without provision for future enlargement. /s/ A. D. Edmonston A. D, Edmonston, State Engineer /s/ Robert L. Ryan Robert L. Ryan, County Surveyor Ventura County /s/ Julian HindvS- Julian Hinds, Consulting Engineer United Y/ater Conservation District Sacramento, California October 1, 1952 A-18 fcl MEMORANDUM OF UNDERSTANDING With Reference to Water Resources Investigation of Ventura County November, 1952 Pursuant to a memorandum of understanding entered into on October 1, 1952, by representatives of the State Division of Water Resources, the Ventura County Flood Control District, and the United Water Conserva- tion District, a meeting was held in the offices of the United Water Conservation District in Santa Paula on October 2li, 1952, among representa- tives of the foregoing agencies. Under terms of the aforementioned memorandum of understanding, both the United Water Conservation District and the State Division of Water Resources -were to prepare estimates of cost for concrete arch dams at the Topa Topa site on Sespe Creek creating reservoir capacities of 50,000, 75,000, and 100,000 acre-feet, respectively, and to review existing yield studies for reservoirs of these capacities. In addi- tion, existing yield studies for a reservoir of 100,000 acre-feet capacity at the Santa Felicia site on Piru Creek were also to be reviewed. As a result of these studies and in accordance with the conclu- | sions derived and concurred in by the attendant parties at the meeting of October Zki 1952, it is mutually agreed that: 1. The reservoir yields independently determined under terms of the memorandum of understanding, dated October 1, 1952, are in agreement. 2. A fill type dam will be constructed at the Santa Felicia site on Piru Creek creating a gross reservoir capacity of not less than 90,000 acre-feet nor more than 100,000 acre-feet. 3. A concrete arch dam, creating a gross reservoir capacity of not less than 50,000 acre-feet, will be constructed at the Topa Topa site on Sespe Creek. A-19 k» The United Water Conservation District will prepare plans and call for bids for construction of concrete arch dams at the Topa Topa site, which would create reservoir capacities of 50,000 and 60,000 acre-feet, with the objective of constructing as large a capacity reservoir as financial limitations will permit. 5. The State Division of Water Resources will study and report or the feasibility of an overpour spillway for concrete arch dams at the Topa Topa site for gross reservoir capacities of 50,000 acre-feet and larger. 6. Construction of not less than 90,000 acre-feet nor more than 100,000 acre-feet of gross reservoir storage capacity at the Santa Felicia site on Piru Creek, and of not less than 50,000 acre-feet of gross reser- voir storage capacity at the Topa Topa site on Sespe Creek, is consistent with an overall plan for the conservation and utilization of the water resources of Ventura County, /s/ A. D. Edmonston A. D. Edmonston, State Engineer /s/ Robert L. Ryan Robert L. Ryan, Engineer Ventura County Flood Control District /s/ Julian Hinds Julian Hinds, Consulting Engineer United Water Conservation District A-20 APPENDIX B GEOLOGY AND GROUND WATER OF VENTURA COUNTY, CALIFORNIA TABLE OF CONTENTS Page ACKNOWLEDGMENTS B-$ CHAPTER B-I. INTRODUCTION B-6 CHAPTER B-II. PHYSIOGRAPHY B-8 Mountains B-8 Valley Areas . • « B-8 Coastal Plain B-ll Submarine Topography B-ll CHAPTER B-III. GEOLOGIC FORMATIONS B-13 Basement Complex • B-13 Cretaceous System . B-lli Paleocene-Eocene Series • B-1J> Oligocene Series 3-17 Miocene Series ....... B-18 Marine Formations B-19 Continental Sediments • B-20 Volcanic Rocks • B-21 Hydrologic Properties B-21 Pliocene Series B-22 Hydrologic Characteristics • B-23 : Lower Pleistocene Series B-23 Santa Barbara Formation • B-2lj San Pedro Formation • B-25> Hydrologic Properties ..... .... B-26 Upper Pleistocene and Recent Series B-27.;. B-l TABLE OF CONTENTS (Continued) Page CHAPTER B-IV. STRUCTURE B-29 I.ults B-29 Northwest-Southeast Trending Faults B-30 Northeast-Southwest Trending Faults B-30 East-West Trending Faults B-31 Faults of Hydrologic Significance . B-33 bids B-3U Folds of Hydrologic Significance • B-33> CHAPTER B-V. GEOLOGIC HISTORY B-37 CHAPTER B-VI. GROUND WATER STORAGE AND SUBSURFACE FLOW B-1;0 round Water Storage B-liO Specific Yield B-UO Selection of Increments B-ll ubsurface Flow B— 1*2 Slope-Area Method B-U2 Rising Water Method B-l|2 Permeability B-i£ CHAPTER B-VII. DESCRIPTION OF GROUND WATER BASINS B-U7 round Water Basins Within Ventura Hydrologic Unit B-5>0 Upper Ojai Basin • • . . B-S>0 Ojai Basin B-£2 Upper Ventura River Basin B-£i* Lower Ventura River Basin B-57 rround Water Basins Within Santa Clara River Hydrologic Unit B-60 B~2 TABLE OF CONTENTS (Continued) Pagj Eastern Basin . . . i B-6( Piru Basin B-6J Fillmore Basin • • B-& Santa Paula Basin B-7C Mound Basin B-7i Oxnard Forebay Basin B-7S Oxnard Plain Basin . . . B-8I Pleasant Valley Basin ......' B-93 Ground Water Basins Within Calleguas-Conejo riydrologic Unit B-9£ Simi Basin B-9£ East Las Posas Basin B-1C West Las Posas Basin ' B-1C Cone jo Basin * B-ll Tierra Rejada Basin . B-ll Santa Rosa Basin B-ll Miscellaneous Areas In and Near Ventura County B-12 Malibu Hydrologic Unit B-12 Rincon Subunit and Rincon Creek Drainage Area B-12 Cuyama River Drainage Area B-12 Upper Portions of Piru Creek Drainage B-12 Bibliography B-12 TABLES Table No. B-l Specific Yield of Sediments B-Jjl B-2 Summary of Permeability Pump Tests B-li6 B-3 TABLE OF CONTENTS (Continued) T ole No. Page B-3 Characteristics of Types of Ground Water Basins B— 14.8 PLATES P ate No. B-1A, IB, 1C Areal Geology Following page B-126 B-2 Stratigraphic Columns - Ventura County Region • Following page B-126 B-3 Submarine Topography and Diagrammatic Sections Following page B-126 B-U ACKNOWLEDGMENTS Data of considerable value in interpretation of geology and ground wa - « hydrology of Ventura County have been made available by the following agencies ai companies. Ground Water Branch, Geological Survey, U. S. Department of Interior Soil Conservation Service, U. S. Department of Agriculture Office of Public Works, U. S. Naval Construction Battalion Center, U. S, Naval Advanced Base Depot, Port Hueneme Office of Public Works, Point Mugu Air Missile Test Center California Department of Natural Resources, Division of Oil and Gas and Division of Mines Ventura County Water Survey Santa Clara Water Conservation District City of Ventura Water Department Standard Oil Company of California General Petroleum Corporation Superior Oil Company The following individuals and organizations have contributed valuable criticisms and suggestions during the course of this investigation. Thomas L. Bailey, Consulting Geologist Frank Bell, Shell Oil Company Harold Conkling, Consulting Engineer K. 0. Emery, University of Southern California Spencer Fine, Richfield Oil Company Edward Hall, Union Oil Company Robert F. Herron, MJM&M Oil Company John F. liann, Consulting Geologist Mn. R. Merrill, Standard Oil Company Henry H. Neel, Tidewater Associated Oil Company Robert H. Paschall, Amerada Petroleum Corporation F, P. Shepard, Scripps Institute of Oceanography Edward L. Winterer, U. S. Geological Survey The assistance of all of the above organizations and individuals, as well as numerous other geologists, landowners, well drillers, and individuals fl gratefully acknowledged. B-$ CHAPTER B-I. INTRODUCTION Ventura County includes an area of approximately 1,8£7 square miles Ach is bounded by surveyed lines chosen irrespective of watershed boundaries jrgeologic features, except along its southwest and in part its west sides, rhf southwestern boundary is the Pacific Ocean. This appendix includes a description of the geology of Ventura County ir. adjacent areas with particular emphasis placed upon those geologic features rt.ch influence the occurrence and movement of ground water* Its purpose is dr'eefold, namely: 1. To describe the geology and water-bearing properties of the rocks. 2, To discuss the effects of geologic structure upon the movement of pund water and the infiltration of sea water, and to describe briefly the rstory of events involving the evolution of the principal structures. 3« To describe the procedures followed in estimating the changes in jound water storage and estimating sub-surface ground water movement that >curred within the principal basins during selected periods of study. The older less permeable formations which yield little water are seated briefly. These rocks are mentioned because: they are the parent source : sediments which fill the ground water basins, in certain localities they !fect the chemical character of the ground water, their position in part con- sols the movement and occurrence of ground water, and they form or delimit the j'ound water basins. The permeable water-bearing formations are described in greater detail, lese deposits comprise the fill of the ground water basins, the principal sources \ ground water supply in the County. Subsurface ground water geology was interpreted largely from the logs I some l,53h water wells, most of which were obtained from the Ventura County iter Survey and some from field canvass. Considerable shallow subsurface data B-6 in the form of 138 electric logs, drillers logs, and core descriptions were ob- tained from the State Division of Oil and Gas and from oil companies operating in various areas. Ground water level data and water analyses were amassed and in certain areas the transmissibility of sediments was estimated by pump testin of wells. All of these data were drawn upon freely in interpreting the geology A perusal of geologic literature revealed a number of maps and report prepared by earlier investigators covering various parts of the County. These existing data were drawn upon freely in the preparation of this report and are listed in the accompanying bibliography. In the course of this investigation, two geologic maps were prepared by compiling data from existing geologic maps, from aerial photographs and from field mapping by the Division of Water Resources in areas where existing data were insufficient. One of these maps is of small scale and depicts the entire County and tributary drainage areas (Plate 10); the second is a detailed map covering the area containing the ground water basins (Plates B-1A, B-1B, and B-1C). B-7 CHAPTER B-II. PHYSIOGRAPHY The southern portion of Ventura County is to a large extent located in he Transverse Ranges geomorphic province, while that portion north of the Santa nez fault (see Areal Geology, Plate 10) is in the southerly section of the Coast langes province (Jenkins 1943). The mountains and valleys in the southern por- ,ion of the County trend nearly east-west, while in the northern portion of the lounty they trend more in a northwest-southeast direction. The physiography of ;he County can best be described by covering the following features: mountains, (ralley areas, the coastal plain, and submarine topography. Mountains The principal mountains in Ventura County include the Piru Mountains (named by Axelrod, 1950), the Santa Ynez Mountains, the Topatopa Mountains and the Santa Monica Mountains. Smaller mountain areas include Oak Ridge, the Santa Susana Mountains north of the Simi Valley area, and the Simi Hills south of Simi Valley. All mountain areas are generally maturely dissected and rugged, with relief ranging from 500 to 2,000 feet. Soil cover is generally thin, but some areas of rolling topography are found where soil cover becomes quite thick. Such areas are generally found in the higher parts of the ranges and may represent remnants of one or more old erosion surfaces. Valley Areas In general, many of the valleys were formed under earlier geologic conditions when the area was nearer base level (in most cases sea level). Since being formed most of the valleys have been uplifted and have undergone additional erosion. Generally, cycles of erosion' and alluviation have been repeated. A few of the valleys are largely the result of structural movements. The Santa Clara River Valley is the most prominent valley in Ventura B-8 County and trends east-west. It is controlled essentially by structural feature: In general, it is a downfolded and faulted trough between mountains to the nortl and south. Deposition by the Santa Clara River and by smaller tributaries has been fairly continuous in most of the valley, while terraces on the side slopes may be due in part to periodic uplift of the sides of the valley with respect to the valley floor. , . Physiography of the Ventura River drainage area has been discussed in j considerable detail by Putnam (1942). Streams in Ojai Valley and the Coyote Creek drainage evidently originally drained westward and eastward respectively toward the Ventura River. Headward erosion of San Antonio and Coyote Creeks has captured those drainages so that they now drain in a southerly direction. Ojai Valley is in a structural depression in which over 700 feet of fluviatile sedi- ments have been deposited. The Coyote Creek drainage area is also in a struc- tural depression, but apparently the area has not been as active as the Ojai Valley area and only thin deposits of alluvium are found there. The small Upper Ojai Valley, according to Putnam (1942), originally drained westward and the headwaters included the upper portion of the present Santa Paula Creek. Most of the alluvial material now found in Upper Ojai Valley was deposited at that time. Subsequent headward erosion of Santa Paula Creek, possibly aided by tectonic movements, has resulted in the capture of the present drainage system, so that Upper Ojai Valley now drains both to the west and to the east. The north-south trending Ventura River Valley has been essentially an erosional feature, a relatively small thickness of alluvial fill being found in the valley at the present time. Terrace deposits indicate that the valley has undergone at least two cycles of erosion. Putnam (1942) presents evidence that the most prominent of the terraces has been gently warped upward, with the axis of the upwarping near Casitas Springs. B-9 The Las Posas upland area extends eastward from Qxnard Plain almost to fjni Valley, and lies between Oak Ridge to the north and the Camarillo and Las bsas Hills to the south. This broad upland area slopes generally to the south, hth erosion and deposition are occurring in places within the area at the present tine. It is possible that Arroyo Las Posas once flowed westward from the vicinity I Somis, north of the Camarillo Hills, to the Qxnard Plain. If so, it was prob- oly diverted south at Somis into the valley it presently occupies by the building- o of alluvial fans extending from Oak Ridge in the area northwest of Somis. Simi Valley is located in a structurally depressed area in which over 90 feet of alluvial sediments has accumulated. Simi Valley has been through more nan one cycle of erosion as indicated by the exposure and present dissection of le older alluvium on the southwest side of the valley. The Simi fault, extending Long the north side of the valley, has apparently been active during deposition f most of the alluvial fill. This is inferred from the 60-foot thickness of the lluvium in the valley just west of where the Simi fault crosses the alluvium, his area is north of the Simi fault or on the uplifted side. The bulk of Simi alley and the greatest thickness of sediments is south of the Simi fault. Cone jo Valley is a broad valley which has been a part of a larger gen- rally east-west valley system lying in part in Los Angeles County. This old alley system was evidently originally developed by a through stream flowing ither east or west. The former drainage system has been captured by headward rosion of Conejo Creek in Conejo Creek Canyon north of Newbury Park, aided by robable northward tilting of the Conejo Valley area and fracturing of rocks. Tierra Rejada and Santa Rosa Valley are both essentially erosional eatures, although up to 200 feet of alluvium has been deposited in Santa Rosa 'alley. The harder portions of the existing volcanic rocks have created tem- >orary base levels resulting in erosion of Tierra Rejada and another smaller B-10 valley in the upper drainage of Santa Rosa Valley. There are several other valley areas in Ventura County which are not described here since they lie outside that portion of the County with which thi report is principally concerned. Coastal Plain The Coastal Plain has been formed by deposition of sediments from the Santa Clara River and from the Calleguas-Conejo drainage area. The land sur- face resembles a large compound alluvial fan having one apex near Saticoy and another near Somis. A group of smaller, but steeper, alluvial fans has been deposited by the smaller creeks draining the hills north of the area, forming an alluvial piedmont. Remnants of terraces along the northern edge of the coastal plain indicate uplift of this part of the plain. This rise might be di to relatively recent upwarping in the Ventura River drainage area (Putnam 1942) possibly augmented by changes of sea level. Submarine Topography Principal features of offshore topography are shown on Plate B-3 whic is taken from U. S. Coast and Geodetic Survey chart number 5202 (Point Dume to Purisima Point). These features are also discussed in papers by Emery and Shepard (1945) and Emery and Rittenberg (1952). Santa Rosa, Santa Cruz and Anacapa Islands are extensions of the Santa Monica Mountains. A scarp-like feature extends in an east-west direction on the south side of the islands and the Santa Monica Mountains. This scarp is cut by the southerly trending Huenem and Mugu submarine canyons which end in the floor of the Santa Monica submarine basin lying south of the Santa Monica Mountains. In addition to these major canyons, three poorly developed or incipient canyons exist between the two majo canyons. The Santa Barbara basin lies due west of the Coastal Plain of Ventura County. This basin is relatively shallow and the slope of the surface west of B-ll m Qxnard Plain is gentle, being as low as five to fifteen feet per mile. In caparison, the slopes of the east-west scarp and the heads of the submarine can- yis are quite steep. Hueneme Canyon cuts across the southeastern corner of the gitly sloping Santa Barbara basin. The heads of the submarine canyons are within a quarter of a mile of the sore, and water-bearing materials are probably exposed along the canyon walls, alowing free contact between sea water and permeable formations. This contact is vry important in considering movement of ground water, since, depending on the direction of the gradient, fresh water can be discharged into the ocean or sea |ber may move into the aquifers. B-12 < CHAPTER B-III. GEOLOGIC FORMATIONS General descriptions of all geologic formations and a short discussio of their role in the hydrology of Ventura County are included in this section. The detailed geologic maps of the southern part of Ventura County (Plates B-1A, B-1B, and B-1C) show the areal extent and distribution of forma- tions based on lithology. Plate 10 is a generalized geologic map of the entir Ventura County and Santa Clara River drainage area. The stratigraphic columns Plate B-2 indicate the age relationship between the various formations by area. The complex geology of Ventura County has been mapped by many people over a period of more than forty years. As a result, present terminology is somewhat confusing to those not familiar with the problems of the area. An attempt has been made in this report to use names of formations which are commonly accepted by local geologists. Wherever lack of agreement seemed to exist the formation names which appeared to be most familiar to local geologist were adopted. Basement Complex The basement complex is composed of granitic and metamorphic rocks of pre-Cretaceous age. The metamorphic rock types include gneiss, schist, hornfel, quartzite, and limestone, indicating that the rocks, before they were meta- morphosed, were mostly sediments. These metamorphic rocks were intruded in Jurassic (?) time by granitic and dioritic rocks (Kew 1924, Wallace 1949, and Crowell 1950 and August and October, 1952 and others). Large areas of the Piru Creek-Santa Clara River drainage area are underlain by deeply weathered granitic and dioritic rocks. Both the igneous an metamorphic rocks are fractured and jointed, being more extensively fractured near large faults. The basement complex is essentially nonwater-bearing, but scattered B-13 cmestic and stock wells obtain small quantities of water from weathered residual r.terials and from fractures. Small springs are fairly common in areas of base- vnt complex, especially during wet periods. Surface water derived from areas of basement complex is generally a ilcium bicarbonate type with moderately low dissolved solids. Cretaceous System Consolidated sediments of Cretaceous age in the Ventura Region have ;en called the Chico formation by early workers, but oil company geologists in le last few years have generally dropped this term. Since the formations have )t been assigned local names, they are generally called Upper Cretaceous rocks, simply Cretaceous rocks. The rocks consist of marine shales, silt stones, indstones, and conglomerates having an aggregate thickness in excess of 7,000 feet. jie shales and silt stones are generally well bedded and dark gray to black in )lor. Upon weathering, they splinter, ultimately disintegrating to gray clayey jils. The sandstones are mostly medium to coarse grained, arkosic, locally Lcaceous, dark gray in color, and wherever weathered they are usually gray or lite. Most exposures show the rocks to be well cemented and indurated; although 1 some areas the degree of cementation is slight. The Upper Cretaceous rocks in the Simi Hills are essentially massive indstones with thin interbedded shales (Kew 1924; Stipp 1943). In the Santa lez Mountains and in a small area of the Piru Mountains, they consist of thin 3ds of shale, siltstone, sandstone, and lenticular conglomerates. Conglomerates i the Wheeler Springs area contain well rounded, well cemented sandstone, ranitic and metamorphic pebbles (Merrill 1952). The Upper Cretaceous rocks re generally folded and faulted and exhibit complex fracture and joint systems. Fossils found in this series include Baculites chicoensis and other arine invertebrates indicative of the age of the rocks. B-14 The Upper Cretaceous rocks are generally nonwater-bearing. In the nil] south and east of Simi Valley, however, water wells obtain domestic and limited irrigation supplies from the massive poorly cemented and fractured sandstones. ; well drilled into one of the sandstones has yielded over 1,000 gallons per minute probably from fracture systems. Small springs generally occur near fractures anc faults in the Santa Ynez Mountains. Most of the springs yield cool, fresh water: but some of them which may be associated with faults such as Wheeler Hot Springs, produce warm water of good quality which is generally low in mineral constituents except boron. Surface water from areas of outcrop of these rocks is generally oJ good quality. Paleocene-Eocene Series Several formations are included in this series in Ventura County. The Martinez formation comprises the oldest rocks of the series. This formation is found in the Piru Creek area (Clements 1937) > the Castaic Creek area (Clements 1937 and Dehlinger 1952), and in the Santa Monica Mountains, but has not been differentiated on Plate 10. In these areas, the Martinez formation consists of marine shale, sandstone, and conglomerate. The Santa Sus ana -Martinez formation of Paleocene and middle and lower Eocene age (Stipp 19^3) in the Simi Hills and on the south side of Simi Valley consists of up to 3>5>00 feet of light colored sandstone, some interbedded shale and a massive basal conglomerate. The lower Llajas formation (Meganos of Kew 192li) consists of about 2,000 to 3>000 feet of olive drab and blue shale, minor interbedded sandstone, and a basal conglomerate. The upper Llajas formation (Te;n formation of Kew 19210 consists of about 2,000 feet of brown to gray micaceous sandstone, siltstone, and some conglomerate (Stipp 19^3) • Both the upper and lower Llajas formations are exposed in the Simi Hills, and are of middle Eocene age. The formations described below are all exposed north of the Santa Clan B-15 Fver Valley and are of upper Eocene age. The Juncal formation consists- -of ■-... . . aout 5,000 feet of marine olive drab to grey silt stone and shale grading down- vrd into concretionary dark grey siltstone and shale. Near the base of the i,ncal formation, there is a black calcareous shale which is the equivalent of lie Sierra Blanca limestone in Santa Barbara County (Merrill 1952). The Matilija {.ndstone lies conformably on the Juncal and consists of about 2,400 feet of trine light colored sandstone with minor interbedded grey siltstone. The Cozy j 1*11 shale lies conformably over the Matilija sandstone and consists of about ; 800 feet of olive drab to grey siltstone and shale. North of the Santa Ynez .uilt, a prominent mapable white sandstone member has been included within the •>zy Dell (Merrill 1952). Coldwater sandstone conformably overlies the Cozy Dell f lale. It consists of about 2, 200 feet of white massive sandstone with inter- sdded red and green silty shale and lenticular conglomerate. In the extreme northwest part of Ventura County a series of brackish iter and marine sandstones and shales of Eocene age have been named the Patti- ay formation (Carlson 1952, Dibblee 1952). Index fossils commonly found in the Paleocene -Eocene formations are isted below: Santa Susana-Martinez formation Upper and lower Llajas formations Juncal formation, Matilija sandstone, Cozy Dell shale, and Coldwater sandstone Turritella pachecoensis Venericardia venturensis Turritella lawsoni , Gale ode a susanae Turritella andersoni Turritella uvasana B-16 Shales of the Paleocene-Eocene series are generally well indurated, and the sandstones are fairly well cemented. The entire series generally forms rugged topography with thin sandy soils. Sandstone beds form particularly massive outcrops and very rugged topography. Rocks of this series are strongly fractured, faulted, and folded. They are generally nonwater-bearing . However, in the hills south and east of Sirai Valley domestic and limited irrigation sup- plies are obtained from poorly cemented sandstones of the upper Llajas and the Santa Susana-Martinez formations. Occasional windmills in the Santa Ynez, Topatopa, and Piru Mountain regions obtain water from the sandstone members of this series. Generally, wells tapping these rocks at depths exceeding 300 to 400 feet encounter water of poor quality. Small springs are generally found in these rocks in the region north of the Santa Clara River. Surface water derived from areas of outcrop of the Paleocene-Eocene series is generally of calcium sulphate type with about 600 to 1,500 and above parts per million (ppm) total dissolved solids, Oligocene Series The Oligocene series in the Ventura County region consists of contin- ental lenticular interbedded conglomerate, sandstone, and shale. No Oligocene marine deposits are known to exist in the area covered by the geologic maps. Th sandstones are poorly to well cemented and generally buff to grey in color. Conglomerates generally contain granitic, metamorphic, sandstone, and chert peb bles and cobbles in a matrix of sandstone or siltstone. The siltstones and snail are generally micaceous and red, maroon, blue, or grey in color. The formation generally weather into red sandy clay soils which are characteristic of areas 0: outcrop of the series. In most of Ventura County, the Oligocene series is called the Sespe formation. In the eastern Santa Clara River drainage area, it has been called B-17 t>, Vasquez formation (Sharp 1935). Beds of probable Oligocene age in the ex- t'jme northern part of the County have been called the Simmler formation (Lbblee 1952). The Sespe formation varies in thickness from 1,200 to 7,300 feet and Mges in age from upper Eocene to lower Miocene, as determined by vertebrate i'ssils (Bailey 1947). The Vasquez formation is of lower Miocene and Oligocene age (Jahns Li!«.0) and is up to 9,000 feet thick with about 4,000 feet of interbedded basaltic tows near its base. The Simmler formation is about 3,000 feet thick and con- iins intrusive andesites in the Lockwood Valley area. The Oligocene series is essentially nonwater- bearing . Sandstones and :nglomerates in the Ojai region and in the Simi Valley area usually yield from . to 100 gallons per minute to wells. One well in the sandstones northwest of mi Valley, however, yields up to 700 gallons per minute. Wells deeper than or 500 feet generally obtain brackish water unsuitable for irrigation. Surface waters derived from outcrop areas of the Oligocene series are nerally of a calcium and bicarbonate-sulphate type with about 300 to 800 ppm tal dissolved solids. In Lockwood Valley and in the Tick Canyon area in Los geles County, a borax mineral, colemanite, is commonly interbedded with the diments, and as a result, surface runoff from these areas may be high in boron ntent especially during periods of low flow. Miocene Series The Miocene series in the Ventura County region consists of several irine and non-marine formations, and includes volcanic rocks. Reference may be .de to the stratigraphic columns (Plate B-2) while reading the short descrip- .ons of the formations which follow. B-18 Marine Formations Sediments deposited under marine conditions include the Vaqueros, Rincon, Topanga, Modelo, and "Santa Margarita" formations. The Vaqueros forma- tion of lower Miocene age consists of 100 to 1,800 feet of gray to brown marine sandstone and shale. The Vaqueros formation has been mapped by some geologists in the southwestern part of the Santa Monica Mountains where it consists of black calcareous shale and minor sandstone beds, but it is included with the Topanga formation on the geologic map of this report because of the extreme geologic complexity. The Rincon formation consists of over 2,000 feet of dark gray to brov. concretionary shale and is exposed only north of the Santa Clara River. The Topanga formation is mapped only in the Santa Monica Mountains ar Conejo Valley area. It is possibly the equivalent of the Rincon formation and the Vaqueros. Vaqueros fossils are found near the ocean south of Boney Mountai, but the beds are included in the Topanga formation because of the complexity of the area. The Topanga formation is mostly black or gray shale in the area sout- west of Boney Mountain. It is composed of sandstone, conglomerate, and brown shale in the Conejo Valley area, and grades into sandstone and conglomerate in the easternmost portion of the area shown on the geologic map (Plate B-1C). ft Topanga formation is closely associated with volcanic rocks. The sediments of the Topanga formation have an aggregate thickness of 6,000 to 9,000 feet, while the intercalated volcanics have a maximum aggregate thickness of about 13,000 feet. The Topanga formation is unconformably overlain by Modelo sandstone and shale. The Modelo formation is variable in lithology but has been subdividec into sandstones and shales by Kew (1924). This subdivision has been followed and used on Plates B-1A, B-1B, and B-1C. Thickness of the Modelo formation var:s from zero to 6,500 feet. The sandstones of the Modelo formation are generally B-19 lght grey to tan in color and are fine to medium grained, and they contain iterbedded clay shales, and conglomerates. The shales of the Modelo formation enerally consist of laminated diatomaceous and cherty shales and clay shales, *jth minor interbedded sandstones and conglomerates. Fish scales and foraminifera ^e usually abundant. The "Santa Margarita" formation includes up to 2,000 feet of tan, ilty, diatomaceous shales, and sandstones of uppermost Miocene age. Some of the ecks have been called the Pico formation by Kew and other names by other workers. e status of some of the sediments included in the "Santa Margarita" formation ' this report is somewhat uncertain. This term has been adopted because of its edominant usage in the western portion of the county. The quotation marks are icessary, since lithology is not consistent and may not resemble that of the -pe locality. Distinctive fossils of the Miocene marine formations are listed below: "Santa Margarita" formation Delectopecten pedroanus Modelo formation Foraminifera only Topanga formation Turrit ella ocoyana Turritella boesei Rincon formation Foraminifera only For foraminifera in these formations, see Kleinpell (1938) and Hanna id Hertlein (1943). mtinental Sediments Continental sediments of Miocene age include the Quatal formation in le Cuyama Valley area and the Mint Canyon formation in the Los Angeles County >rtion of the Santa Clara River drainage area. The Quatal formation consists of ,500 feet of red gypsiferous clay, sand, and poorly cemented conglomerate under- pin by 3,000 feet of red sandstone and poorly cemented fanglomerate (Dibblee ?52). The Mint Canyon formation (Kew 192/+) consists of 4,600 feet of lacustrine B-20 and fluviatile sandstone, conglomerate, clay, and some marl. Fresh water molluscs, plant remains, and land vertebrate remains have been found in the Min Canyon formation (Jahns, 1940). Volcanic Rocks The volcanic rocks, mostly of Miocene age, associated with the Topani formation include up to 13,000 feet of pyroclastics and basaltic flows. The pyroclastics include agglomerates, mud flows, and rhyolitic rocks. Andesitic ar basaltic dikes, sills, and plugs intrude the flows and the associated Topanga sediments. Fossiliferous marine shales, sandstones, and conglomerates occur from place to place interbedded with the flows. The volcanics are faulted, highly fractured, and moderately folded. Hydrologic Properties Most of the formations of the Miocene series are essentially nonwatei bearing. Until 1953, the volcanics in the Conejo Valley and Tierra Rejada are* constituted the principal formation in the Miocene series which was significanl as far as water supply is concerned. Further discussion of the water-bearing properties of the volcanics is included in the description of the ground water basins. Present information indicates that none of the Miocene marine sedimets are potential major ground water reservoirs. That is, few wells could be drilJd; which would yield large quantities of water from these rocks. Deep wells in the Miocene marine formations generally obtain brackish or salty water. The Mint Canyon formation contains permeable beds which are potential sources of supply. As far as is known, no irrigation wells obtained water from the Mint Canyon formation up to 1953. The Quatal formation, of Miocene age, in the Cuyama Valley area contains extremely permeable gravels. It is possible that -'- B-21 jels yielding sufficient water for irrigation could be obtained if drilled in utable locations. At present, only domestic wells are known to be supplied rra this formation in Ventura County. Surface water derived from areas of Miocene marine formations is gener- ly a sodium-calcium-magnesium sulphate type containing from UOO to over 2,000 ppm veal dissolved solids. The runoff from areas of Miocene continental beds is ;eterally a calcium sulphate type with from 200 to over 1,5>00 ppm total dissolved ic.ids. Pliocene Series Formations of Pliocene age include the Pico, Saugus, and Morales forma - i:ms, and the Ridge Basin Group. The Pico formation consists of marine gray sandstone, blue gray shale, i lenticular conglomerate. These materials weather to a dull brown silty clay ;l1. Landslides are common in areas of outcrop. The Pico formation is uncon- rmable with underlying and overlying formations in the Las Posas area but else- 2re is generally conformable. It varies in thickness from 12,000 feet in the itura area to zero in the Las Posas area. In the Ventura area, the Pico, Modelo, i Santa Barbara formations are conformable and interfinger. The Pico-Saugus ntact in the Saugus-Castaic area in Los Angeles County transgresses time so that 3 lower part of the Saugus formation, near the town of Saugus, is the age equiv- ient of the upper portion of the Pico formation to the west. Typical fossils and in the Pico formation include Turritella cooperi , Pecten healyi , and Chi one rnandoensis . The Saugus formation consists of up to 2,500 feet of non-marine brown nd, slightly cemented gravel, and gray or tan clay. Kew (19210 originally eluded the San Pedro and portions of the Santa Barbara formation as described this report in the Saugus formation, but it is limited here to the eastern d of the Santa Clara River Valley in Los Angeles County. Vertebrate fossils B-22 collected by W. H. Corey and identified by Chester Stock indicate that the Saugiu formation in the Castiac-Saugus area is of upper and middle Pliocene age (verbal communication from W. H. Corey, April, 1953). The Ridge Basin group of sediments is located between the San Andreas and San Gabriel faults south of Quail Lake, largely in Los Angeles County. This group consists of up to 18,000 feet of continental shale, sandstone, and conglom- erate (Eaton 1939, Crowell 1950, August 1952, and Dehlinger 1952). Fresh water fish, vertebrate, and plant remains indicating Pliocene age are found in the Rid| Basin group (Axelrod 1950 and Crowell August, 1952). The continental Morales formation is located in the northwest portion of Ventura County to the east and north of the Cuyama River. It consists of about U,000 feet of gray to buff gravels and sands (Dibblee 1952). Hydrologic Characteristics The Pico formation is generally nonwater-bearing or yields salty water to wells. Some water wells in the Los Angeles County portion of the Santa Clara River drainage area probably obtain water from the permeable sands and gravels of the Saugus formation. A few water wells were observed which penetrate the Rijp Basin group in Hungry Valley and Peace Valley, upper tributaries of Piru Creek mr U. S. Highway 99. A few irrigation wells are drilled into the Morales formation in Santa Barbara County. Both the Morales formation and the Ridge Basin group are possible potential ground water reservoirs. However, low rain-fall in these areas would probably result in limited replenishment of the formations after the ground water was depleted by pumping. Surface water from the Pliocene formations is generally a sodium sulphti type with from about U00 to over 2,000 ppm total dissolved solids. Lower Pleistocene Series Sediments of the lower Pleistocene series comprise some of the most B-23 aportant water-bearing formations in Ventura County. These include the- -Santa, irbara and San Pedro formations. anta Bar bara For mation | The Santa Barbara formation is of lowermost Pleistocene and uppermost liocene age (Bailey 1935) • It had been previously included in the Pico forma- ion by Kew (1924). It has been called upper Pico by Cartwright (1928), Driver 1928), and Waterfall (1929). The thickness and lithology of the Santa Barbara ormation varies considerably from about 4*000 feet of mudstone, shale, and minor ;and stone beds near the City of Ventura to about 1,000 feet of sand, gravel, and linor clay in the Tapo Canyon area and 800 feet of sand and clay in the southern &rt of the Qxnard Plain. Most of the clays and shales are blue in color when • >esh, and contain plant remains and distinctive foraminiferal faunas. The ilightly cemented buff colored gravels and sands on Oak Ridge referred to in this report as the Grimes Canyon member of the Santa Barbara formation extend south- vestward under the Las Posas area and into the Pleasant Valley area, where they pecome mostly fine to medium sand. Typical fossils found in the Santa Barbara formation are listed below: Vertebrates (Bailey 1935) Equus cf . occiden talis Invertebrates (Bailey 1935) Pec ten caurinus Pecten bellus Foraminifera (Natland 1952) Cassidulina limbata The foraminifera found in the Santa Barbara formation in the Hall Canyon area indicate deposition at depths of 125 to 900 feet below sea level, i/\hile the lithology of the Grimes Canyon member near Grimes Canyon indicates beach or B-24 littoral deposition. The lithology and fossils indicate that the present area of the Santa Clara River Valley was under fairly deep water during deposition oj sediments which comprise the Santa Barbara formation. A fluctuating shoreline extended from near the Santa Monica Mountains through Moorpark and eastward through the Tapo Canyon area. The northward extension of the shoreline is now concealed by structure or destroyed by erosion. San Pedro Formation The San Pedro formation is of lower Pleistocene age. North of the Santa Clara River, it interfingers with the underlying Santa Barbara formation. South of the Santa Clara River, it is generally unconformable on the Santa Barbara formation. In the Oxnard Plain-Pleasant Valley area, the available oil well logs indicate a conformable contact. The San Pedro formation consists of up to 4,000 feet of marine and continental gravel, sand, and clay. North of th Santa Clara River, the San Pedro formation consists of extremely lenticular bed with many scour and fill features. The base of the San Pedro in this area con- tains abundant marine fossil^ but from near the middle of the formation to the top, marine fossils are rare except near the City of Ventura and the Ventura River. An oil well drilled through part of the San Pedro formation near the mouth of Aliso Canyon encountered mostly blue-green clay with abundant wood fra- ments and plant remains, indicating fresh water swamp deposits. A prominent sx and gravel zone up to 300 feet in thickness containing marine fossils on the soil side of Oak Ridge and beneath the Las Posas area is called the Fox Canyon membe " in this report. The Fox Canyon member can be traced on the surface and in wate and oil well logs in the Las Posas area and is found at or near the base of the San Pedro formation. The Fox Canyon member extends into Pleasant Valley and th Oxnard Plain, but available well logs indicate that it is probably not as homogeneous there as it is in the Las Posas area. B-25 During deposition of the San Pedro formation the Qxnard Plain was ]5Stly submerged to depths of about 125 feet and was being filled by deposition .-om the ancient Santa Clara River. The Santa Clara River Valley itself was sub- Lding so that the thickness of sediments is now greater there than anywhere else i Ventura County. As the basin filled with sediments, the shoreline moved west- ird, and some of the San Pedro formation is, therefore, of continental origin. 3 a result, nearly all the San Pedro formation exposed near the Ventura River Dntains marine fossils, but only the base of the formation contains marine ossils just east of Santa Paula. Nearly all the San Pedro formation in the Las Posas and Qxnard Plain reas was deposited in shallow water, probably partially in lagoons. Typical fossils in the San Pedro formation are listed below: Vertebrates (Bailey 1943) Equus cf . occidentalis Chendytes lawi Invertebrates (Bailey 1935) Crepidula princeps Cancellaria tritonidea Cantharus fort is Pec ten Circularis Foraminifera (Natland 1952) Elphidium hannai Rotalia becarrii Some of the deeper sediments deposited in Simi Valley and Ojai Valley ay be of lower Pleistocene age but are described herein with the upper Pleisto- ene Series. iydrologic Properties Ground water occurs in sands and gravels of the Santa Barbara and San B-26 Pedro formations. The Santa Barbara formation probably contains water of poor quality in the Santa Clara River area and portions of the Oxnard Plain-Pleasant Valley area as is indicated by electric logs of a few oil wells. The Grimes Canyon member contains fresh water of good quality in the Las Posas area and in the Pleasant Valley area. At the time of this investigation, only a few wells were obtaining water from the Grimes Canyon member or other sands of the Santa Barbara formation alone. A few other wells obtained water from the Santa Barbar as well as the overlying San Pedro formation. The San Pedro formation yields water to wells in the Santa Clara River Valley and in the Las Posas, Oxnard Plain, and Pleasant Valley areas. As far ae is now known, all water in the San Pedro gravels and sands is of good quality except that below about 2,000 feet in the Santa Clara River area, where a few electric logs indicate that the water may be slightly brackish. Surface runoff from the Santa Barbara and San Pedro formations is gene ally of fair quality. Upper Pleistocene and Recent Series Sediments of upper Pleistocene age include most of the gravels, sands, and clays younger than the San Pedro formation. In general, they are all un- disturbed or only gently folded in contrast to the San Pedro and older formation The upper Pleistocene series in the Oxnard Plain-Pleasant Valley area extends from the top of the San Pedro formation to within about 20 to £0 feet of the surface. It consists of up to £00 feet of interbedded marine blue clay and sand, alluvial silt, and stream deposited sand and gravel. The principal aquifer on the Oxnard Plain is a stream deposited gravel of upper Pleistocene age which is called the Oxnard aquifer in this report. In the Pleasant Valley area, the upper Pleistocene series contains lenticular gravels which yield wateit wells. From available well log data, the base of the upper Pleistocene series B-27 apears to lie unconformably on the San Pedro formation in Pleasant Valley and i parts of the Oxnard Plain. The alluvium in Simi and Ojai Valleys is probably largely of upper and Twer Pleistocene age, approximately the upper $0 feet being Recent, Most of te alluvium in the Santa Clara River Valley is also Pleistocene, and the total tickness of alluvium in the river bottom ranges from five or six feet at Blue C.t to over 200 feet elsewhere. Most of the terrace deposits in Ventura County re probably upper Pleistocene, Recent Alluvium is quite thin over most of Ventura County, probably no rire than 60 or 70 feet thick. It consists of sand, gravel, and clay. Most uter wells obtain water from materials underlying the Recent alluvium except i those areas where the water table is high. Both upper Pleistocene and Recent sediments are more fully discussed rider the description of ground water basins. B-28 CHAPTER B-IV. STRUCTURE The purpose of this chapter is to discuss the geologic structure of Ventura County, placing particular emphasis on those features which affect the occurrence and movement of ground water. Ventura County is located in two regions of fairly distinct structural characteristics which coincide with the geomorphic provinces mentioned in Chapte B-II. The portion of the County north of the Santa Ynez fault (see Plate 10) is in the southern Coast Range province, and the portion south of this fault is generally included in the Transverse Range province. At the extreme northeast corner of Ventura County, the Sierra Nevada and Mojave Desert provinces meet bot the Coast Range and Transverse Range provinces near Lebec. Many major structural features in Ventura County trend east-west, al- though considerable variation in direction exists. Principal structural feature of Ventura County and adjacent areas are shown on Plate 10. Plates B-1A, B-U3 al B-1C show additional details of structure of the southern portion of the County. Geologic cross-sections are also included on these latter plates to illustrate structural features. Faults Faults in the Ventura County region may be divided into northwest- southeast trending, northeast-southwest trending, and east-west trending faults. Some faults have been displaced horizontally and some vertically, while both com ponents of movement have occurred on others. Aside from the major or prominent faults shown on the geologic maps, there are minor faults and fractures too numerous to indicate. Nearly all faults are actually zones of faulting, the width of the zone generally being greatest on the larger faults. Relative direc tions of movement along the faults, where known, are shown on the geologic maps. B-29 Ic - thwest-Southeast Trending Faults Major faults trending in a northwest- southeast direction include the la Andreas, Nacimiento, Pine Mountain, Hot Springs, San Gabriel, and Santa lisana faults. The San Andreas fault is well known and is the longest fault in «iifornia. Horizontal or more correctly right lateral movement has been pre- l/iinant, with over 300 miles displacement possibly occurring since Jurassic time suggested by Hill and Dibblee (1953)« The Nacimiento fault extends into Ventura mty near the Cuyama River. The Hot Springs fault, which is located southwest i Lockwood Valley, may be an extension of the Nacimiento fault, the two having m displaced by the Big Pine fault. The San Gabriel fault is another major alt of California. Like the San Andreas fault, the predominant movement has 2n horizontal, and Crowell (Oct. 19^2) has presented evidence for about 2$ miles rizontal displacement along the fault since Miocene time. The Santa Susana tit, in the Santa Susana Mountains of Ventura and Los Angeles Counties, is a rust fault which dips to the north and appears to override the east end of the tc Ridge fault (Herron 1952 and Sheller and Bien 19U7). rtheast-Southwest Trending Faults The most prominent northeast- southwest trending faults are the Big Pine d Sycamore Canyon faults. According to Hill and Dibbleo (1953), the Big Pine ult is probably an extension of the Garlock fault (not shown), the two having en displaced by movement on the San Andreas fault. Hill and Dibblee report a ssible horizontal displacement on the Big Pine fault of lk miles. The Sycamore nyon fault and associated faults in the Santa Monica Mountains are about 1$ les long, and as far as can be determined have had mostly a vertical component movement. It is possible that a major northeast-southwest trending fault exists ong the southeast edge of Pleasant Valley, but no evidence could be found that B-30 such a fault affects water-bearing materials, and it has not been shown on the geologic maps. East-West Trending Faults Most of the remaining major faults in Ventura County are essentially east-west trending. The northernmost of these faults will be discussed first, and those on the south side of the county last. The Pine Mountain fault is a north dipping reverse fault, and is appar ently a branch fault connecting the Big Pine and Hot Springs faults. The Tule Creek fault, although more than 20 miles long, is apparently not directly connect with other major faults. The Santa Inez fault is another of the major Calif orni faults which have probably had both horizontal and vertical components of move- ment. The Santa Ana fault, which crosses the Ventura River drainage area, hs had fairly recent movement, and probably has been an important factor in the accumulation of the alluvial fill in Ojai Valley. The San Cayetano fault is a north dipping reverse or thrust fault wit* a known low dip of about 20 degrees near Fillmore, and of about 60 degrees norM of Santa Paula. The San Cayetano fault actually consists of two or more branch* often with soft, easily deformed sediments between them (Sheller and Bien 1°U7)< Nonwater-bearing formations have been thrust over the San Pedro formation along hi San Cayetano fault in the area northeast of Fillmore. North of Santa Paula, Eocene sediments have been thrust over Pliocene sediments as shown on Section C-' Plate B-1B. The Oak Ridge fault extends along the south edge of the Santa Clara River Valley from Saticoy to a point about two miles southeast of Piru, where 11 turns southward into Oak Ridge and is cut off by the Santa Susana fault. The Saticoy fault may be a westward extension of the Oak Ridge fault or a branch of t The Oak Ridge fault has been penetrated by several oil wells drilled on Oak B-31 .dge, and it has been found that the fault dips southward about 60 degrees, .der formations have been thrust up from the south over younger San Pedro sedi- >nts (see Section C-C f , Plate B-1B). Evidence for the location of the Saticoy fault shown on Plate B-1B was >und in logs of oil wells and in differences in water level elevation across it. ; is not certain what happens to this fault at depth, but it does appear to die it westward and cannot be detected in well logs north of Montalvo or along the jach south of Ventura. The south side of the Saticoy fault has been uplifted jlative to the north side. The Simi-Santa Rosa fault system consists of several branches and tensions. The north side of this fault system has been generally uplifted ;lative to the south and has apparently been one of the causes for the accumula- uon of the thick alluvium in Simi Valley. East of Simi Valley the relative .rection is reversed, with the south side being uplifted, suggesting a hinge or ;issors type fault. It could not be determined during this investigation whether either the ?ringville fault zone or the Camarillo fault are extensions of the Simi-Santa >sa fault system. The Springville fault zone is located on the south side of le Camarillo Hills and consists of at least two parallel faults, portions of ■ lich are well exposed on the surface. It is possible that the fault zone con- .nues eastward south of Somis, but outcrops and well log data are not available ) show this. This fault zone does not appear to affect the Cxnard aquifer in le Qxnard Plain although it does affect the San Pedro and older formations, at ;ast near the Camarillo Hills. The Springville fault zone dips steeply to the >rth with the north side being uplifted relative to the south. The Camarillo fault extends along the south side of a low hill near ie town of Camarillo and curves northeastward toward Santa Rosa Valley. Evi- $nce for this fault is found in well logs, physiographic features and water level B-32 data. The fault is probably nearly vertical and the north side is uplifted. The fault appears to fade out eastward and cannot be detected beyond the Camarill Airport. Faults of Hydrologic Significance The major faults in Ventura County which are known to have a barrier effect on ground water are the Saticoy and Springville faults and a portion of th Camarillo fault. Some of the other major faults described above with accompanyir folding generally affect ground water indirectly by deformation of the water-beai ing materials. This deformation in some cases has resulted in changes of cross- section area of water-bearing formations, and in exposure and erosion of portiom of the formations so that they can be recharged by surface waters. Some of the faults of Ventura County may also be avenues of escape for deeper waters of poor quality. Faults which may be in this category include the Hot Springs and Santa Ynez and possibly the San Cayetano and Oak Ridge faults. Evidence for escape of deeper waters appears in the analyses of spring water, anc in some cases in analyses of ground water in alluvium near the faults. The Saticoy fault affects the San .Pedro formation and possibly the ovei lying alluvium. It appears to act as a partial barrier to flow of ground water with a water level differential across it of up to. 100 feet (see Plates II4B, 1$B, and 16B). The barrier effect of the fault seems to be. most pronounced near the town of Saticoy. Its effect on ground water in the area of the Santa Clara Rivei bed is not known due to lack of well control. The fault also appears to die out or become less effective so that no prominent differentials in water levels can be detected across the fault two or three miles -westward of Saticoy. The barrier portion of the Saticoy fault also results in the" deflection of a part of the underflow from Santa Paula Basin westward into Hound Basin, the remainder- flowing through or over the- fault into-Oxnard Forebay Basin. B-33 The Springville fault zone has displaced the San Pedro and underlying ^nations. This displacement and the reduction of permeability caused by move- it as shown on surface exposures of the fault has caused a barrier to south- ed movement of ground water from beneath the Gamarillo Hills into Pleasant Val- r Basin. The barrier effect is evidenced by up to 60 feet water level differ- iial across the fault in aquifers of the San Pedro and Santa Barbara formations, is probable that the Springville fault zone has not affected alluvium in the lard Plain area. Study of well logs indicates that the Camarillo fault displaces the t Pedro formation and probably some of the alluvium near the town of Camarillo. iund water contours generally do not indicate that this fault acts as a barrier flow of ground water in the San Pedro formation. Field observations indicate, fever, that local drawdown of pumping wells does not extend across the fault. >er levels in the lenticular aquifers of the alluvium do appear to be higher the north side of this fault, suggesting that it may act as a barrier to the :.thward movement of ground water in the alluvium. Folds All rocks and sediments in Ventura County, except those most recently •osited, have been folded. Most of the folds, like the faults, trend in an st-west direction. In general, there are three prominent anticlinal areas which mally consist of several smaller folds. These are the Topatopa Mountains near Santa Ynez fault, Oak Ridge, and the Simi Hills south of Simi Valley. The ita Monica Mountains in the Ventura County area are essentially a north dip- g homocline. The principal areas which are essentially synclinal in structure I: the Cuyama drainage area northwest of the 3ig Pine fault, the area between I near the intersection of the San Andreas and San Gabriel faults which has si called the "Ridge Basin" in geologic literature, the Santa Clara River syn- B-3U I cline, and the area south of Oak Ridge. Some of the folded formations in the high hills and mountains may form limited ground water basins under certain conditions, but since most of these structures are not explored by wells, they are not discussed further. Folds of Hydrologic Significance The most significant folds from a ground water standpoint are the Sant Clara River syncline, the Montalvo anticline, and the series of folds in the syn- clinal area south of Oak Ridge, all of which affect water-bearing materials. Santa Clara River Syncline . The Santa Clara River syncline extends from the ocean south of Ventura up the Santa Clara River into Los Angeles County The origin of this syncline was closely related to movement of the Oak Ridge and San Cayetano faults, as well as the Ventura Avenue anticline (see Plates B-] and B-1B). It is probable that the Santa Clara River syncline was initially folded without faulting, and faulting occurred later when the sides of the fold became fairly steep (Reed, 1933). Of interest here is the fact that the water- bearing San Pedro formation has been folded in the Santa Clara River syncline, resulting in erosion and exposure of the upturned edges so that ground water«ts now replenished by surface water . The north flank of the folded San Pedro fonr- tion is exposed from the ocean to a point about three miles east of Santa Paula and may be recharged by rainfall penetration and stream percolation. The south flank of the syncline may be partially eroded and covered by alluvium along the a of the Santa Clara River and partially covered by older formations which have been thrust up along the Oak Ridge fault. Montalvo Anticline . The Montalvo anticline, which affects the San Peco formation, extends from the ocean up the south side of the Santa Clara River, crosses the river near Montalvo, and continues eastward south of the Saticoy fau! • The Montalvo anticline appears to be cut off by the Saticoy or Oak Ridge fault B-35 ar the west end of Oak Ridge. This anticline is shown on the geologic map late B-1B) as a single continuous fold, but may consist of two or more indi- iual anticlines. The area in the vicinity of the anticline is complicated by .ior faults and folds and it is difficult to determine details of the structure i their effect on the movement and occurrence of ground water. It seems clear at the Montalvo anticline has folded the San Pedro formation so that it has sn eroded and covered by alluvial gravels in Oxnard Forebay Basin, As a re- Lt, some aquifers of the San Pedro formation are most likely in hydrologic itinuity with ground water in the overlying alluvium. Folds South of Oak Ridge , The folds in the area south of Oak Ridge in » Las Posas area (see Plate B-1C) affect the principal aquifers there. These Lds result in the aquifers being exposed in certain areas where they can be harged by surface waters and buried in other areas where water wells can be Llled into them. The upturned edges of the aquifers and in some cases the ssts of anticlines serve as ground water storage reservoirs for the deeper por- ms of the aquifers. Change of storage probably occurs in the Fox Canyon aqui- f in portions of the Long Canyon, Moorpark, and Camarillo anticlines. In the bper synclinal areas ground water within the aquifers is usually confined by jrlying silts and clays. B-36 CHAPTER B-V. GEOLOGIC HISTORY The geologic history of Ventura County has been very complex. Portion, of the area have been repeatedly covered by the sea and then uplifted, while oth' portions have been below sea level nearly all the time. A few areas have been generally above sea level so that sediments were not deposited on them. The Ter tiary history of Ventura County has been closely related with the history of a larger region which includes much of Santa Barbara County, the Channel Islands, and a portion of Los Angeles County, and is designated Ventura Basin in this re- port. The term basin as used here means geologic basin. The northern portion of this large area has been called the Santa Barbara embayment. The Channel Is- lands and parts of the Santa Monica Mountains have been called Anacapia by Reed (1933) and Reed and Hollister (1936), but for purposes of discussion the two are) are discussed here as one. Ventura Basin during most of Tertiary time was a brol east-west trending downfolded belt, with gentle uplifting occurring to the north and south. History of events prior to Tertiary time is obscure due to lack of e- posures of pre-Tertiary rocks. The axis or deepest portion of the basin where t* thickest sediments are found varied during Tertiary time. During Eocene time th axis was located in the northern portion of the County. In Oligocene time, the axis appears to have been along the central part of the County, and in Miocene time the major axis appears to have been in the south portion in the Santa Monic Mountains, with perhaps a secondary basin existing in the central portion of the County. During Pliocene and Pleistocene time the axis near the central part of the County remained the most prominent. It appears to have migrated slowly sout- ward, so that at the present time the deepest part of Ventura Basin coincides wii the axis of the Santa Clara River syncline (see Plate B-1B). Since Eocene time, much of the northern portion of Ventura County has been eroded. The eroded area has grown larger as the axis moved southward and the northerly areas were uplifted. In the Santa Monica Mountains great thick- B-37 isses of volcanics and marine sediments accumulated during Miocene time, but us area was apparently uplifted in the Pliocene since no Pliocene sediments have y=n found there. These flexures in the earth's crust were accompanied by fault- Lg and gentle folding of the sediments. In middle Pleistocene time, however, riding and faulting was accelerated during the Santa Barbaran orogeny, This riddle Pleistocene orogeny resulted in overturning of folds, subsequent breaking > the folds into thrust fault, (Reed 1933), and the development of geologic fea- tres essentially as they are today. Evidence is available that thrusting occur- b first from the south and later from the north (Herron 19H>3). After the mid- •eistocene orogeny the land was eroded into gently rounded hills and mountains, ^ile upper Pleistocene deposits were still being deposited in the valleys. Dur- g upper Pleistocene time, however, fluctuations in sea level, possibly related world wide glaciation, caused changes in base level of the streams. During riods of low sea level, renewed erosion of portions of the valley fills and the llling uplands occurred. As the water level rose after the last glacial period, reams deposited their loads and filled the valleys once more. The latest events appear to include the following: (1) continued tivity along certain faults; (2) continued folding such as the folded terraces the Ventura River drainage area (Putnam 19h2); (3) renewed downcutting and adward erosion of streams, which may be due to a combination of man's alternation natural conditions and climatic changes. The events since the mid-Pleistocene orogeny have had considerable effect development of the submarine canyons. It is not known if the canyons existed fore that period. Whether they did or not, however, it is possible that the •ad of sediments carried by the ancient Santa Clara River may have been of con- derable importance in present development of the canyons. During the upper .eistocene, the Santa Clara River continually shifted its course so that at var- •us times all parts of the Oxnard Plain were covered, and the river probably B-38 discharged at various times into the ocean at all points along the coast from thf Santa Monica Mountains to its present position. Discharge of sediments onto the ocean floor in the area of the steep east-west submarine scarp south of the Coastal Plain may have resulted in submarine landslides, mudflows, and turbidity currents, which once started would continue from time to time as river sediments and transported beach sediments were dumped into the head of the carbons. The ocean floor west of Qxnard has a gentle slope, and it is probable that canyons have not been started there due to low velocities of turbidity currents and othe: transporting agents. It would appear that the submarine area west of Cxnard has been aggrading while the area to the south of Qxnard has been undergoing degrada- tion and dissection which has been at least in part responsible for the formatioi of the submarine canyons. B-39 CHAPTER B-VI. GROUND WATER STORAGE AND SUBSURFACE FLOW The purpose of this chapter is to explain the procedures used to deter- iLne quantitative estimates of ground water storage and subsurface flow. Ground Water Storage Ground water is stored within the interstices of sediments and in racks or fractures of solid rocks. The changes in ground water storage occur- ing over selected periods of study wore estimated for the more important ground ater basins within the County. Results of these studies are discussed in Chapter I, In general, the procedures of estimation required first a determination of he change in the volume of saturated sediments that occurred over a selected tudy period and second an estimate of the percentage of this volume that con- ained extractable ground water. The first factor was obtained by computing the olume of sediments that lay between the water tables that existed at the start nd close of the study period; the second factor from evaluating the average eight ed specific yield of the sediments between water tables from available ell logs. Storage changes over the periods of study were computed by multiply- ng changes in volume of saturated sediments by average weighted specific yield. pecific Yield The specific yield of a sedimentary deposit is the ratio of the volume f water which it will yield by gravity after being saturated, to its own volume, ustomarily expressed in per cent. In its South Coastal Basin Investigation, the (ivision of Water Resources conducted extensive field and laboratory investiga- tions for the purpose of assigning specific yield values to various types of taterial appearing in well logs. These procedures are described in Bulletin No. .5 "Geology and Ground Water Storage Capacity of Valley Fill" (Division of Water iesources, 1934). With slight variations, the values determined in this earlier B-40 work and Bulletin 46 "Ventura County Investigation" were adopted for compiling the change of storage estimates presented here. The task of assigning specific yield values to the sediments appearing in logs was simplified by dividing all basin sediments into eight general categories. These included soil, clay, clay-sand, clay-gravel, tight sand, sand tight gravel, and gravel. Sand, gravel, and clay, which constitute the bulk of the basin sediments, were generally found to be well differentiated on the driller's logs. Combinations of these materials, however, were frequently des- cribed by such unique terms as "ooze", "muck", "cement", etc. Materials so des- cribed were placed, based on the judgment of a geologist, into one of the above eight categories. Table B-l indicates specific yield values assigned to the general categories. In certain instances, these values were altered slightly whenever field observations indicated the advisability of changes. TABLE B-l SPECIFIC YIELDS OF SEDEiENTS Material ; Specific Yield (Per Cent) Soil, including silty clay 3 Clay, including adobe and hard pan Clayey sand, including sandy silt 5 Clayey gravel 7 Sand 25 Tight sand, including cemented sand 18 Gravel, including gravel and sand 21 Tight gravel, including cemented gravel 14 Selection of Increments Each ground water basin was subdivided into smaller areas. Units of 100 acres were adopted in the larger basins where well logs were abundant and larger areas were used in basins for which little data were available. The sedi- ments underlying each such subarea were separated at selected depth intervals. In this manner, each basin was divided into zones, the storage capacity of which B-41 culd be conveniently estimated. The change in ground water storage for each etire basin was then computed as the sum of the changes occurring within the znes. Subsurface Flow Two methods were used to determine subsurface flow. These were the Eope-area method and the rising water method. : ope- Are a Method The slope-area method is based on the commonly used form of Darcy's law, PAI, where Q equals subsurface flow in gallons per day passing through the :oss-sectional area A in square feet; P is permeability in gallons per day per =uare foot; and I is slope of water table at the cross-section in feet per foot, lis method is fairly reliable in cases where cross -sectional area can be de ter- med from well logs, permeability can be estimated by pump tests, and the ground iter slope can be accurately measured. sing Water Method The rising water method of computing subsurface flow is applicable jiere rising water occurs perennially and where the cross-sectional area of iturated sediments is unknown. The method has been mentioned by Tolman (1937) id a variation of the method was used by Kimble (1936). The rising water method s also based on Darcy's law. Let Qt equal total subsurface flow past a cross-section of the valley .11 at the point of zero rising water, X, upstream from the point of maximum .sing water, Y (see diagram below). Let Qu be the subsurface flow at the point ' maximum rising water and Qr the maximum rising water at any time. Assuming lat little or no water is lost by diversion or evapo- transpiration between X and B-U2 Y, and that steady flow conditions exist it follows that: Qt =» Qu + Qr At point X the total subsurface flow may be expressed as Qt «= PAI and Qu + Qr = (pa) I where P ■ permeability A = cross-sectional area I ■ slope of water table at point X, as measured in wells just upstream from X. It is assumed that: 1. Flow is horizontal. 2. The materials are essentially homogeneous. 3. The change in cross-sectional area due to change in water levels is negligible. 4. Permeability is constant throughout the section. Under these assumptions, the variations in Qr must be dependent only upon I. Two periods t-, and t 2 may be taken so that Qu + Qi^ = (PA)^ (1) and Qu + Qr 2 - (PA)I 2 (2) Subsurface flow or Qu is nearly constant as long as any rising water occurs, since I at Y is essentially determined by the surface of the stream. Dividing (l) by (2) , Qu + Qr x = PA (I x ) Qu ♦ Qr 2 = PA (I 2 ) and solving for Qu Qu ■ I x (Qr 2>" • I 2 (Qr 1 ) J 2 - h B-43 The maximum rising water, Qr, must be measured. Error may be intro- aced if water losses are not taken into account or if the stream is not measured t the point of maximum rising water. Rising water measurements obtained by Dth the Division of Water Resources and the Ventura County Water Survey were sed to compute subsurface flow in the basins of the Santa Clara River by this ethod. Qr Q> Qt = PAI Qt - Qr+Qu Slope of Water Surface = I -Z 4c B-44 In order to complete the hydrologic studies of the Santa Clara River basins it was necessary to estimate the decrease in subsurface flow when water level of the basins were drawn down and rising water stopped. In order to do this the logarithm of rising water plus previously estimated subsurface flow wa plotted against basin storage depletion and found to be nearly a straight line. This line was then projected past the point where zero rising water occurred an the projected line was used to estimate subsurface flow for conditions of zero rising water. This method of estimating subsurface flow with zero rising water is based on the assumption that the storage depletion of the basin and the slop, of the water table upstream from the area where rising water occurred are relati, and that the change of wetted cross-sectional area due to change in ground wate level is negligible. In general, it was found that these factors were related during the period of record, so that the assumption appears to be valid. Permeability 1 Pump tests to determine permeability were conducted where possible. These data are summarized in Table B-2. Permeability was computed using non- equilibrium methods as outlined in the Division of Water Resources "Draft of Report of Referee" No. 506806, of the West Coast Basin, February, 1952. Slight variations in methods as suggested by Wenzel (1942) and Jacobs and Cooper (194* were used where necessary. In general, the recovery and the drawdown methods were used depending on conditions. These methods depend on time-rate of recowy after pumping stops or time-rate of drawdown during pumping. The last column c Table B-2 indicates relative reliability of results due to conditions at the tie of the tests. B-45 03 a -P SL co CD •H E-> TJ « _ C «H O O O ■P C 0) CD bO-H 03 O h •H O 4h +3 «H CO CD O o >> -p (h -P •H O d ft *H o &H -Q (0 ft cfl c S o b U 1 H aj cd H P 3 > •H a3 H P •H X) U ■P •H CD O CO a O CO &H ■g to fc o 3 r a a) H U o3 E-< C5 c ^ 0} CD to a 1 a3 < m o -P (l) 43 10 CD J> O 3 o CM CM o o CO > +3 s to 03 H a. o 8 o Oh > G -r) a) C CO 03 1 03 U P 3 H CM 3 O o) +3 •H ft to O a o H o 03 ft, -d o cS NO o o o -3- NO CM o 8 o o O o o Q iH H vO > o o H 03 J.3 CM . CM CO o > o 1 o cd U « Q CM CM " C" 5 P l> > l/\ 9 CM • CM CO > v v • 3£> H 3 CM nO 3 o o O O o O O o o O en * •> •> •\ CO -4" o t> o vO CM c-- H CM H H u & to Oj o P-. (0 o3 C & o 03 O W tt, e O o «H o 0. +3 ^ u •H .H $H o •H H o O 03 O s O p* &H ^ D-. fL O > ~' ^ o - <» fVJ 8 O O • O r I ■ • o 43 &H CO -Ci" o> to | o -g d. o CM O CO vO o CM CO -d- CM T3 03 x: 8 8 o CM CM I eg O ■n Oh i CO p H 03 CM C ^s. 3 > O O CO 8 o o o bO 03 vO c-\ > oJ •H ^ rH > I U U ft > o 1 p I +3 •H O g c*> -P CM C O O NO c<> CO en on O O o CM P 2 u S Q «H fxn o3 43 •H O 0-. CO > o o ^" XJ p . cn fe U J <" S (DX H o3 -P ^"^ 4> oJ 3 CO X B-46 CHAPTER B-VII. DESCRIPTION OF GROUND WATER BASINS Seventeen ground water basins delineated in Ventura County in the course of this investigation are discussed in the following paragraphs. The boundaries of these basins are shown on Plate 11. In addition, there is dis- cussed herein an additional basin known as Eastern Basin, which is located in Los Angeles County but which affects the regimen of flow in the Santa Clara Rive: in Ventura County, Several further ground water bodies which presently yield bu' little water, are discussed under the name of the locality in which they occur, namely, Malibu hydrologic unit, Rincon subunit and Rincon Creek drainage area, Cuyama River drainage area, and upper portions of Piru Creek drainage. The boundaries of ground water basins in most instances conform with geologic features such as contacts between permeable and impermeable formations, fault zones of low permeability, or changes in subsurface lithology which affect movement or mode of occurrence of ground water. These boundaries were establishl from available data, including well logs, areal geology, and hydrologic observa- tions. In general, there are three types of ground water basins in the County These include (1) basins composed of unconsolidated sediments or alluvium, (2) volcanic rock basins, and (3) basins composed of consolidated rocks. The first type of basin comprising unconsolidated sediments or alluvium has been further divided into two sub-types: the simple type basin in which ground water occurs in a single unconfined body, and the complex basin in which ground water occurs in more than one aquifer. The characteristics of these types of basins are sum- marized in Table B-3. B-U7 5 s H s 1 ft o CO a. ft o CO o CO Q o V en • 1 • X) P OH >» 2 rtj« J S « n).HH H C +>T)ach Si ^ d 1? d CD O O (D C » g d o -PO03 c o p d o Is 1-1 cS S R O cd f>j.H O ft O g r-l «H J3 8 § » co d d O U U a M O a O t3 k cr 1 cp Sh cd S CO o «H ^ o 0) 0)«H _p , — 1 • -P cd c co cd ? H xJ c U -H CD £ cd o taO ^ CO a> x» o x; co -p O C S O tH ft 03 rH R , H « C R CO X» h -p 3 O C X! O Jh 3 +3 ' S «H H -P i« ftO • O >a ilO d d O CD -P U +3^00 O o u aw) O ^S N +3 (D XJ CD 3 »-. , u U 3X0 R U CD +3 • +3 0+3 2 O X> O X» HO >s«H TJ U !«{ O tt Cd +3 H CD «H • cd 3 ? cd O •» £h ?H H «n C CO cd co -H cd cd d H Sh +3 a d CO 0) © ,r\ ft tH O • +) ^ +) +5 3 fn «h S (D w a d jd ^ •H O d cd M CD ft P CO CD CD O k £3 «H XJ CO Cd cd o d U q 3Q o -H «h a 1 XJ I 6 5 u CO . CO « mo ^ +3 co o hfl SXJ 3 •H H X) 3 Id !p H H d • •H -H x: H H co C ID • 01 SHO •h a S-i -r* .rt x: H IS S © -H a >» M cd j>> tiO Jh X! d h E *H B -H ft X +3 «H s O •H r-H H X! • O X X Cd •H H iH O >H H ft d ^ ro 5 'co -P tH CO CO cd £ cd -P •H +3 3 >> rt oj +3 cd p -H to Qfl U Ps tlO R W) U S o o •rl SO) •H ^ H Jh C C d > ^ co CD CO CQ X ■9 CO PQ U cd u < o d CO b> •OX) U CO CO H. -P CO cd -H O 9> > CO ■9 & CD O d H co •H <0 ,0 3 o xi d H +3 cd O cd »H d •coed 4 Jh o d cd > SB CO Oh Cu co g 6 ft w co g aidurrs x8-[duioo d •H CO cd CO CO CQ x» H c i s O -H g O X H o o H C CD D CO 4 o > B-48 CD I •H P C o o s 1 En CD (0 •\ H C to X) ^ OH •N cd -H H T) C • *3 *

o -H o to CD ft cd 43 ft o 43 t»P TJ «H rt rt c O B 3: cd CO CD W c ft • CD 3 3 X ft • p +3 QJ 3 tO Cd O rH P 0) 2 ft g cd -H P O ft P CO O (M 0) TJ i O P. tf ft j>> ctS cd to ft bO ft E-" 42 o CO CD -H H J>s G +> U r-{ r-i O cd ft rH ,~^ to cd ft | a> *h q o > cd -H u P •rj to tj W rH cd >;, to c cd 3 HfflX CD 43 cd 'H ft 3 *h X O <4 to 3 >^-rojO p a> -h to ft C +3 C rH P 0) -H O cd -H 3 o o > to C O S £ CD a p 3 ^ C •H «H -H 43 «H «H cd to o q 3 o o o a a 2 CO -H 0Q CO 43 to CO b0 CD -p -j -H P P O U CO S f-. ft H O to cd 'H cd cd £ eu CO Cu cu, 4 ^S to o cd O 43 (15 nwater-bearing sedi- ments of the Sespe formation are exposed in a small hi bh of this hill there are a few deep wells in the valley floor which yield < 1/ snail amounts of water although their logs indicate only sedimentary materia 3e observations sug- gest that at the westerly end of Ojai Valley, a relat ely thin nantle of allu- vium overlies essentially no nwater -bearing Sespe for n. Subsurface outflow from Ojai Valley to Ventura River Basin is therefore robably insignificant. Ground Water Storage Capacity and Specific Ppecific yield and storage capacity of the water-bearing materials and canges in storage occurring over selected study periods were computed in the manrr described in Chapter B-VI, and results are discussed in Chapter II. Total usab^ storage capacity of Ojai Basin is estimated to be about 70,000 acre-feet. Yield of Wells . Wells in the alluvial basn generally yield from 100 to 600 gallons per minute with a range in specific opacity of from three to twenty. Wells tapping the older surrounding formations usually yield from two to five gallons per minute but occasionally yield as mch as £0 gallons per minute. The specific capacity of wells in the older formatins is usually very small. Upper Ventura River Basin Upper Ventura River Basin lies within the Upper Ventura River subunit which includes the Ventura River Valley, the Coyotf Creek drainage area, and that portion of the San Antonio Creek drainage area tha lies downstream from Ojai Valley. The basin ranges in elevation from 200 to lore than 800 feet above sea level, and consists of about h, 990 acres underlai by alluvium. Water-bearing -^ alluvial deposits of very limited areal extent als occur along Coyote Creek and San Antonio Creek, but these deposits are not comdered to be of sufficient size to be regarded as ground water basins. B-5U . Geology . The ; ium consists of Upper Pleistocene and Recent depos- ts of gravel, sand, and cla . Well logs indicate the alluvium of Ventura River alley to vary from 60 to ] feet in depth. In the San .Antonio and Coyote Creek M ** reas, it apparently varies rom £ to 30 feet in depth. These deposits are lanked by Tertiary sediment consisting of marine and continental sandstone, con- ;lomerate, and shale, and in aide the Rincon, Modelo, Vaqueros, Sespe, Coldwater, nd Cozy Dell formations. Th Sespe formation underlies a large portion of the loyote Creek drainage area art is composed chiefly of well cemented sandstone with ntercalated lenses of conglcerate. The sandstone is locally fractured. The longlomerates occur as both porly and well cemented deposits. It is often diffi- :ult to distinguish the conglmerates from overlying alluvium in well logs. Some rater wells penetrating the Mdelo formation obtain water of inferior quality. The Ventura River i an antecedent stream that has cut across the re- ;ional structure and does not flow along a structural trough. The Tertiary rocks ire generally folded and faul ?d, but the Recent deposits are relatively undis- turbed . Occurrence of Grounc Water . Ground water occurs in alluvium and to some jxtent in the fractures and irerstices of the Tertiary formations. In general, free ground water conditions pevail throughout the entire subunit. However, Locally confined bodies of grond water may exist. While wells in the Sespe forma- tion are being drilled, the wa sr level occasionally rises, indicating the exist- 3nce of localized confined bod js of ground water. Movement of Ground Wr.er . Ground water moves tfi^ough the alluvium fol- lowing the slopes of the sur. i drainage, ^timately^ Jg Lov^ ^^itura River 3asin below Foster Park. Dire ions of J Bre m< groundwater contours on Plate £ lU-A, j ,and l£ Jle fa ^ Jted as crossing this basin in an e: t-we suggesting that they cut the alluvium or form barriers to movement of ground water . Replenishment and Depletion of Ground Water , Ground water is replen- ished chiefly by percolation from the Ventura River and to a lesser extent by pei eolation of direct rainfall and the unconsumed portion of water applied for irri- gation and other uses. A slight amount of recharge is probably derived from sub- surface inflow through the flanking Tertiary formations. Ground water is deplete by pumped extractions, consumptive use of phreatophytes, effluent discharge, and, subsurface outflow. Subsurface Inflow and Outflow. Subsurface inflow is practically neglr gible being limited to seepage through fissures and pores in the Tertiary forma- tions. In 1906, the City of Ventura constructed a partial subsurface barrier in the alluvium of the Ventura River near Foster Park. The purpose of the barrier was to create rising water to be diverted for domestic and irrigation purposes. The easternmost end of this barrier was not completed, and a perennial subsurfac- flow exists around this end. This flow was estimated by the slope area method described in Chapter B-VI and was found to vary between 7S>,000 and 100,000 gallot per day or about 100 acre-feet per year. Ground Water Storage Capacity and Specific Yield . Total storage capacy of the basin is estimated to be about 10,000 acre-feet. The average specific yield of the contained sediments is estimated to be about eight per cent. ' r Yield of Wells . Irrigation wells in. the alluvium yield about 600 gallu per minute with specific capacities ranging from 10 to 200. Both well yield and specific capacity are influenced by the regimen of the Ventura River. Following cessation of surface flow in the river, both yields and specific capacities fall below the above values. B-S6 , cer Ventura River Basin Lower Ventura River Basin includes the alluvial deposits of the Ventura jj'^er that lie between Foster Park and the ocean, and the basin ranges in eleva- dm from sea level to about 200 feet above sea level. It has a surface area of but 2,670 acres. The valley floor of Canada Larga has been excluded from this degrees toward the south and strikes to the east extending into Mound Basin. Available data suggest that the San Pedro formi tion near the river mouth is at least partially hydraulically isolated from the river alluvium by relatively impervious material, possibly of lagunal or Paludal origin. The alluvium is considered to be within the Lower Ventura River Basin overlapping the San Pedro formation which belongs hydrologically within Mound Basin. This conclusion is substantiated by the following observations: 1. Static water levels in wells tapping the San Pedro formation have been above the elevation of the bed of the Ventura River indicating that ground water in the San Pedro formation is confined. 2. The electric log of one of the above wells indicated water of poor quality in the river alluvium; yet this same well has continually produced fresh water from the underlying San Pedro formation. 3. Water levels in wells tapping the San Pedro formation fluctuate in rapid response to tidal fluctuations, further indicating that ground water in th< San Pedro formation is confined. Movement of Ground Water . There are few wells situated in Lower Ventu. River Basin; consequently, no ground water contour map was constructed of this area. In general, ground water moves in a downstream direction, ultimately dis- charging into the ocean. No barriers to ground water movement are known to exis B-S8 Replenishment and Depletion of Ground Water . The basin is replenished I percolation from the Ventura River, by percolation of rainfall and the uncon- smed portion of water applied for irrigation and other uses, as well as by sub- iirface inflow from Upper Ventura River Basin. Inflow from flanking Tertiary ■ diments is probably small. Depletion occurs by surface and subsurface outflow, Imited pumped extractions, and consumptive use of phreatophytes. Subsurface Inflow and Outflow . Subsurface flow in the alluvium of the ntura River near Foster Park constitutes one of the principal sources of supply Lower Ventura River Basin. Subsurface outflow from the basin probably dis- targes to the ocean during periods of high ground water level. Ground Water Storage Capacity and Specific Yield . Pumping draft on wer Ventura River Basin is negligible. There are no irrigation wells, a few ■andoned domestic wells, and one sump pump. For this reason, no estimates of ange in storage were compiled for this basin. Yield of Wells . There are no known irrigation or domestic wells opera- .ng in Lower Ventura River Basin which obtain water from the alluvial fill. B-59 Ground Water Basins Within Santa Clara River Hydro logic Unit Ground water basins within the Santa Clara River Hydrologic Unit inclui Piru, Fillmore, Santa Paula, Mound, Oxnard Forebay, Oxnard Plain, and Pleasant Valley Basins. These basins are the most productive in Ventura County. Plate 1 shows the location of the ground water basins, and their physical characteristic are summarized in Table 11. Plate B-1B shows details of geologic structure and extent of formations in this hydrologic unit. Eastern Basin Eastern Basin lies within Los Angeles County; more explicitly it com- prises the water-bearing formations of that part of the Santa Clara River Valley lying east of Ventura County. Since it is not in Ventura County, it was not studied in detail during the course of this investigation. It is discussed here because it is tributary to other basins in Ventura County. Pumping from this basin effects the regimen of both surface and subsurface flow in the Santa Clara River. The boundaries of Eastern Basin were not determined exactly, except for the boundary with Piru Basin on the west. :: Geology . The watershed tributary to Eastern Basin contains sedimenta formations of marine and non-marine origin, some volcanic rocks, and large areas of granitic and metamorphic rocks. These formations are shown on Plate 10 and include alluvium, Saugus and Pico formations, Ridge Basin group, "Santa Margarit Modelo, Vaqueros, Mint Canyon and Martinez formations. Of these formations, the Saugus and Quaternary alluvium are of principal interest. Water derived from k B-60 a:3as of non-marine formations may be fairly high in boron due to occurrence of >:on minerals in these sediments. The Saugus formation in this area consists of continental sand, clay, ai poorly cemented gravel and attains a maximum thickness of 2,500 feet. These mterials have been faulted, folded, and eroded. In the valley areas the Saugus frmation is overlain by up to 100 feet of alluvial sand and gravel with some cay and silt. Occurrence of Ground Water . Ground water is derived principally from wlls tapping the Saugus formation and the Quaternary alluvium. It is known tat ground water within the deeper aquifers often occurs as confined water where- ? that within the alluvium is usually unconfined. No attempt was made in this investigation to delimit the extent of the different aquifers in Eastern Basin. Movement of Ground Water . No ground water contour maps were constructed I Eastern Basin by this Division during this investigation. Ground water contour ps of this area are published in "The Annual Report on Hydrologic Data" by the >s Angeles County Flood Control District. Replenishment and Depletion of Ground Water . Ground water is reple- Lshed by stream percolation, penetration of direct precipitation and the uncon- imed portions of water applied for irrigation and other uses as well as imported iter released by the City of Los Angeles from Bouquet Canyon Reservoir, and also > a minor extent by subsurface inflow from the older semi-permeable formations i.at flank the basin. The ground water basin is depleted by pumped extractions, jnsumptive use of phreat ophytes^ and effluent discharge. Subsurface Inflow and Outflow . An undetermined amount of inflow enters le basin from older semi-permeable formations that flank the water-bearing sedi- mts. Subsurface outflow from Eastern Basin is negligible and is discussed in le paragraph on subsurface inflow to Piru Basin. B-61 Ground Water Storage Capacity and Specific Yield , No attempt was made to estimate change of storage or total storage capacity within Eastern Basin during this investigation. Yield of Wells . No measurements of well discharge were made in this basin, although both irrigation and domestic wells exist. Several highly pro- ductive wells tap the alluvial sands near the river and are supplied directly by percolation from that source. One such well reportedly yields 2,000 gallons per minute. Irrigation wells are also known to tap the Saugus formation, but thi yields of such wells are not known. Piru Basin Piru Basin ranges in elevation from blO feet to 800 feet. The highest elevation within the watershed is U,592 feet attained at Hopper Mountain. It comprises a surface area of about 6,520 acres. The greater portion of the groun< water basin underlies the alluvial area of the Santa Clara River Valley. The eastern boundary of the basin is at Blue Cut which is located about one mile wesi of the Los Angeles County line. The western boundary is arbitrarily located as shown on Plate B-1B. Geology . The principal water-bearing formations of Piru Basin are alluvium of Recent and upper Pleistocene age and the San Pedro formation. Rocks adjacent to the valley floor include the Sespe, Vaqueros, Modelo, "Santa Marga- rita", and Pico formations, all of which are essentially nonwater-bearingin this area but which may contribute water of poor quality to the water-bearing material Alluvium in Piru Basin is about 8£ to 200 feet thick and consists of river deposited sand and gravel of Recent and upper Pleistocene age which is not readily differentiated from the San Pedro formation. In Blue Cut at the extreme east end of the basin, alluvium is about 6 to l£ feet thick. On the south side c B-62 mvl Basin alluvium overlies a shelf -like feature of nonwater-bearing rocks (see Sologic Section J-J', Plate 12-A). The San Pedro formation does not outcrop in this basin, but it is t.:>ped at depth by many wells. Water wells reach depths of up to 1,000 feet in Piru Basin and their Lgs indicate that the San Pedro formation is characterized by gravel, sand, and sne clay. Several water wells which were in the process of being drilled were r,sited in the course of the investigation. Samples of material taken from these J lis indicate that most of the San Pedro formation, to depths of 800 feet, was Jposited under conditions similar to those which prevail in the Santa Clara tver today. The nature of the sediments deeper than 800 feet is not well known, jmples from an oil well drilled near Cavin Road on the north side of the river |st west of the center of the basin are comprised of similar materials to depths :' 1,000 feet. The silt content increases appreciably to 1,200 feet, the maximum Jpth of the well. The electric log of an oil well about one mile east of the wn of Fillmore indicates that thick inter bedded sands and clays extend to depths ' li,000 feet. The San Pedro formation has been folded along the Santa Clara River ncline. At the Oak Ridge and San Cayetano faults older rocks have been thrust ■er the formation. Two oil wells in the mountains about one mile north of the lley first penetrate the Modelo sandstone and shale, then the San Cayetano tult, and finally the San Pedro formation which is only gently folded. The •west angle of dip of the San Cayetano fault as shown by these wells is about ) decrees toward the north. The Oak Ridge fault dips about 60 degrees southward J evidenced in oil wells drilled on Oak Ridge south of the Santa Clara River illey. The trough axis of the Santa Clara River syncline is folded upward south- tst of the town of Piru, where the San Pedro formation has apparently been B-63 truncated by erosion. The San Pedro formation is reduced in cross- sectional an westward from Piru to the State Fish Hatchery, where the narrowest part of the valley is located. Well log data indicate that the cross- sectional area may al> be slightly reduced by a gentle upwarp of the base of the San Pedro formation near the fish hatchery. Occurrence of Ground Water . Ground water is generally unconfined in both the San Pedro formation and the overlying alluvium. Movement of Ground Water . Ground water generally moves westward, as shown on the water level contour maps, with minor contribution from the north ad south sides of the basin (see Plates 14-B, 15-B and 16-B). The water table slos appears to be fairly steep just southeast of Piru, and it is possible that this steep slope may be related to the upturned edge of the San Pedro formation be- neath the alluvium. Slope of the water table decreases from an area south of Piru and cor tinues to decrease toward the State Fish Hatchery which is located on the Piru- Fillmore Basin boundary. Cross-sectional area of the water-bearing materials i the least near the Fish Hatchery where it results in a steeper water table slop. Farther west the slope decreases as the cross-sectional area increases. The point where the steepening occurs cannot be accurately determined, but its loca tion appears to vary with water levels in Piru Basin. The boundary of Piru Basin was drawn arbitrarily near the Fish Hatchery where the maximum amount of rising water usually occurs, but could also be located to the east or to the wet of the assumed boundary. It is clear that as long as a westward gradient of ti water table exists, subsurface outflow will continue. Historically, this westvrc gradient has always existed; although it has become less as the basin was depleec and greater as the basin was replenished. Because of the considerable depth of the San Pedro formation at the State Fish Hatchery it is likely that subsurface B-64 iow out of Piru Basin will continue as long as water levels are higher than in Jllmore Basin. There is no evidence available indicating the presence of a lult which would function as a ground water barrier, as suggested by previous :ivestigators . Replenishment and Depletion of Ground Water . Ground water in Piru isin is replenished by percolation in stream channels and in the Piru spreading -ounds, by percolation of direct precipitation and the unconsumed portion of iter applied for irrigation and other uses, and probably by a minor amount of lbsurface inflow from adjacent semi -permeable formations. Ground water is de- leted by pumped extractions, consumptive use of phreatophytes, effluent discharge, rid by subsurface flow into Fillmore Basin. Subsurface Inflow and Outflow . Subsurface flow into the Piru Basin from ne Eastern Basin is probably negligible because of the thin alluvial cover at the asin boundary in Blue Cut. Subsurface flow out of Piru Basin into Fillmore Basin as been estimated by the rising water method (see p. B-U2) to be thirty second- eet. Subsurface flow out of Piru Basin will occur whether there is rising water Ir not, but will be decreased somewhat after rising water stops and as the water .able is lowered and its gradient decreased. Ground Water Storage Capacity and Specific Yield . Results of change of rround water storage estimates are discussed in Chapter II. Forty- five well logs /ere used to determine specific yield of the sediments. The mean weighted speci- Tic yield of the interval between the highest water levels of 19 UU and the lowest )f 19!?1 is estimated to be 16 per cent. To estimate total storage capacity of the 'round water basin, it was assumed that usable depth of the ground water basin is L,000 feet, that the average area at depth is about 6,000 acres, and that the spe- cific yield does not change appreciably with depth. By multiplying these figures, B-6S the storage capacity for Piru Basin is estimated to be 6000 x 1000 x .16 or 960,000 acre- feet, or on the order of one million acre-feet. Yield of Wells . Yield of irrigation wells in Piru Basin varies from 600 to about 2,000 gallons per minute, with an estimated average of 800 gallons per minute. Specific capacity averages about 70. Yield of wells on the shelf on the south side of Piru Basin is fairly high when water levels are high, but when the water level falls and the alluvium is dewatered the wells go dry. Fillmore Basin Fillmore Basin which comprises a surface area of about 16,870 acres ranges in elevation from 280 to U70 feet in the Santa Clara River channel. Max- imum elevation in the immediate drainage area is hf959 feet at Santa Paula Peak, Two prominent features of this area include Timber Canyon which reaches an elev* tion of about 2,200 feet, and the Sespe uplands north of the Santa Clara River and west of Sespe Creek. I* Geology . Water-bearing materials underlying the basin include alluviu of Recent and Pleistocene age and the San Pedro formation. Formations adjacent to Fillmore Basin include the Santa Barbara, Pico, Modelo, Vaqueros, and Sespe which are essentially nonwater-bearing, but may contribute limited amounts of water of poor quality to the water-bearing materials. See Geologic Section H-H Plate 12-A, for general relationships of the water-bearing materials. The alluvium comprises gravel, sand, and some clay up to 250 feet in thickness. The alluvium is difficult to differentiate from the underlying San Pedro formation in the valley floor area of the basin. A study of water well logs in the Sespe uplands indicates that the alluvium is underlain, at least in part, by the San Pedro formation. The alluvium in the Sespe uplands consists upper Pleistocene and Recent alluvial fans which have been deposited on the - B-66 uturned and eroded edges of the San Pedro and older formations (See Geologic Sction H-H 1 , Plate 12-A). The upper Pleistocene (or older) alluvium has been fitly dissected and somewhat folded. It is being dissected in some areas and cvered by Recent alluvium in others. The alluvium in the Sespe uplands comprises favel, gravelly clay, and clay and is generally reddish in color. Timber Canyon, located about four miles northeast of Santa Paula, is loored by Recent alluvium. A large alluvial cone extends from Santa Clara River llley up the floor of Timber Canyon. The surface material on this cone is Etremely coarse, poorly sorted, subangular gravel. Water well logs indicate tat this coarse material contains considerable clay and that the cone is up to !0 feet thick just north of Highway 126. On the south side of Fillmore Basin, in the Bardsdale area, the alluvium :erlies a shelf of semi -permeable rocks which have been thrust up by the Oak : dge fault. The alluvium overlying this shelf is up to 180 feet thick. It is .obable that this alluvium includes upper Pleistocene materials. The San Pedro formation outcrops north of the valley floor from the fwn of Santa Paula to the Sespe uplands, where it is concealed beneath alluvium, e San Pedro formation dips about hO degrees to the south near Santa Paula and comes steeper eastward until it is overturned at Timber Canyon. Cores from an 1 well northwest of the town of Fillmore indicate that the San Pedro formation : relatively flat lying at depth below the gently dipping San Cayetano fault and . the valley area of Sespe Creek. The structure of the San Pedro formation in te Sespe uplands is concealed by alluvium, but available data suggest that addi- onal unknown faults complicate the geology of this area. The San Pedro formation is about U,000 feet thick in this basin and it •nsists of gravel, sand, and clay. The uppermost portion of the formation is .ream deposited, probably by the ancient equivalent of the Santa Clara River, le lower and some of the middle portion of the San Pedro formation contains B-67 marine fossils which indicate deposition in a shallow marine environment. Field inspection of the San Pedro formation on the north side of the Fillmore Basin indicates that the beds are extremely lenticular and discontinuous. Clays are fairly common, but are also discontinuous. Structurally Fillmore Basin is a part of the Santa Clara River synclint Along the Oak Ridge fault on the south of the basin, the semi -permeable forma- tions underlying Oak Ridge have been thrust up against the San Pedro formation. The San Cayetano fault swings northward near the town of Fillmore and does not directly affect the ground water geology west of Sespe Creek. The cross-sectional area of the San Pedro formation is slightly reduce by local warning of the Santa Clara River syncline east of Santa Paula, where th assumed boundary of the basin is located. Water levels and available geologic data do not indicate faulting in this area. ft . complex feature exists in Fillmore Basin on the south edge of the Sespe uplands just north of Highway 126. Inspection of the older alluvial sedi- ments in the small hills in this area indicates that an anticlinal structure is present as shown on the geologic map (Plate P.-1B). Cores from an oil well drill! here indicate the presence of faulted and folded sediments at shallow depths. I is possible that an east-west trending fault which may affect ground water exist in this area, but water level contours do not indicate the presence of such a fault. Occurrence of Ground Water . Ground x^ater occurs in the San Pedro form- tion and in the overlying alluvium and is essentially unconfined. Movement of Ground. Water . Ground water moves westerly in Fillmore Basn with some minor contribution from the south and north sides. There is a decreas in cross-sectional area of water-bearing materials from the vicinity of Sespe Creek to the arbitrary boundary between Fillmore and Santa Paula Basins. Slope B-68 t the water table decreases westward toward this boundary. Near the narrowest Lint which is taken as the western boundary of Fillmore Basin, the slope of the iter table increases, decreasing again as the cross-sectional area increases lto Santa Paula Basin. The point of steepest slope appears to be variable under .fferent water level conditions, and is actually a fairly wide zone rather than sharp line. This is the reason that an arbitrary boundary is used, just as ■tween Piru and Fillmore Basins. As far as can be determined, no cross fault lich affects ground water exists at this boundary. Replenishment and Depletion of Ground Water . Ground water in Fillmore isin is replenished by subsurface inflow, by stream percolation, by percolation * direct precipitation and the unconsumed portion of water applied for irrigation id. other uses, and probably by a minor amount of subsurface flow from the San sdro formation and adjacent semi -permeable formations. Ground water is depleted r pumped extractions, consumptive use of phreatophytes, effluent discharge, and lbsurface outflow. Subsurface Inflow and Outflow. Subsurface inflow into Fillmore Basin 'om Piru Basin has been estimated by the rising water method to be about thirty jcond-feet. Well log data are not sufficient to accurately check this estimate r the slope -area method. Subsurface outflow from Fillmore Basin into Santa lula Basin has been estimated ^y the rising water method to be about sixteen jcond-feet. Subsurface outflow from Fillmore Basin will continue,' even after . .sing water stops, but it is likely that the underflow would decrease somewhat. Ground Water Storage Capacity and Specific Yield . Results of ground iter storage estimates are discussed in Chapter II. One hundred five well logs ire used to estimate specific yield and change of storage. The change of storage stimate includes the Sespe upland area. The mean weighted specific yield of B-69 the interval between the highest and lowest historic water table is estimated to be 12 per cent. The total storage capacity of the upper thousand feet of Fillmore Basin is probably on the same order of magnitude as Piru Basin, or about one million acre-feet using an estimated area of 12,000 acres. The average spe- cific yield is smaller in Fillmore Basin, but the area is larger than Piru Basin, The maximum total storage capacity of the basin is unknown because the effective depth of the basin has not been determined. This depth may reach ii,000 feet, which is the base of the San Pedro formation as found in oil wells near the town of Fillmore. Yield of T fells . Irrigation wells in Fillmore Basin yield up to 2,100 gallons per minute, and their average yield is about 700 gallons per minute. Sp< cific capacity of the wells varies considerably but probably averages £0. Yield: of wells on the shelf on the south side of the basin and on part of the Sespe uplands are generally smaller than in the valley floor, due to limited depth of alluvium. Santa Paula Basin Santa Paula Basin ranges in elevation from 1U0 to 280 feet, although the maximum elevation in the local drainage area is 2,7^0 feet on Sulphur foun- tain. The ground water basin underlies the flat alluvial area of the Santa Clar River Valley and comprises a surface area of about 13,520 acres. The boundary between Santa Paula and Fillmore Basins has been discussed under the description of the latter basin. Between Santa Paula Basin and Hound Basin, the boundary is also an arbitrary line as discussed below." Geology . Water -bearing materials in Santa Paula Basin include the alluvium of Recent and upper Pleistocene age and the San Pedro formation. Rod underlying the San Pedro formation and adjacent to the basin include the Santa B-70 Rrb^ra, Pico, Modelo, Vaoueros, and Sespe formations, which are generally semi- rvrmeable and may contain water of poor ouality. The alluvium consists of up to 200 feet of stream deposited gravel, snd, and some clay and cannot be easily differentiated from the underlying San Fdro formation. The alluvium near Saticoy and in the northwestern portion of the tsin consists of yellow silty clay overlving and interbedded with stream gravels i shown on Geologic Section G-G' of Plate 12 -A. Lenticular gravels interbedded vth this clay may locally yield water of poor ouality to wells. The clay forms scap over the gravels and pinches out to the south and to the east. This yellow jlty clay was probably deposited as alluvial fans by streams draining the area trth of the basin. Similar silts are still being deposited in the area. The San Pedro formation consists of U>000 feet of gravel, sand, and (.ay. The lower third of this formation contains fossils indicating a marine cigin. The upper two-thirds is generally devoid of fossils and consists pri- urily of stream deposits. Exposures of the San Pedro formation exhibit irregular lidding. Scour and fill features are common with individual gravels often grading rterally into sands or silts within a very short distance. It is probable that 'ctreme variations also exist in the San Pedro formation underlying the valley Loor, but local changes cannot be detected from drillers' logs. The deepest water well logs indicate that gravels of the San Pedro for- ition persist to depths of at least 800 feet. Oil well lo?s and outcrops indi- ite that the total thickness of the San Pedro formation may be 1^,000 feet. The 3tal effective thickness is unknown, as far as water-bearing characteristics are Dncerned, but it is probably at least 1,000 feet as indicated by one oil well log. The most significant structural features in Santa Paula Basin are the mta Clara River syncline, the Oak Ridge fault, and the Saticoy fault. As dis- issed in Chapter B-IV of this appendix, it is probable that the Saticoy fault is branch of the Oak Ridge fault, although it may simply be an extension. Where B-71 it can be traced, the Saticoy fault forms the boundary between Santa Paula and Oxnard Forebay Basins, but since it cannot be traced in the bed of the Santa Clar River, an arbitary boundary was used at that location. The San Pedro formation has been cut off on the south by the Oak Ridge fault. The upturned edge of the San Pedro formation is exposed on the north side of the basin. It has been foldc into the Ventura Avenue anticline and the Canada Larga syncline as shown on Plate B-1B. These structures probably affect ground water in the outcrop area of the San Pedro, but they appear to die out to the east and probably do not affect ground water in Santa Paula Basin. Occurrence of Ground Water . Ground water occurs in the San Pedro forms tion and in the overlying alluvium. The ground water body in most of the basin is unconfined, but where clay lenses exist, confined ground water is evident froi water level records of wells. i Movement of Ground Water . Ground water generally moves in a westerly direction as shown by ground water elevation contour maps (Plates lU-B, 15-B, arw 16-B). At the west end of the basin the Saticoy fault forms a barrier impeding movement of ground water into Oxnard Forebay Basin. The effectiveness of this fault as a ground water barrier is demonstrated by a pronounced difference in water level elevation on either side of the fault. On the upstream side of this fault, near Saticoy, water levels range from 5>0 to 100 feet higher than the leve.'i existing on the downstream side. Between Santa Paula Basin and Mound Basin a relatively steep gradient in water levels exists. The cause of this steeper gradient is not readily apparent. There is no distinct and sudden drop in water level as characterized by a fault barrier, and it is believed that the steep gradient is due to a decrease in the permeability of the sediments underlying the area, although there may be some faulting in the San Pedro formation. B-72 Replenishment and Depletion of Grou»d Water. Ground water is replen- hed by stream percolation, by penetration of direct precipitation and the un- nsumed portion of water applied for irrigation and other uses, by subsurface flow fjKin Fillmore Basin, and probably by a mi*or amount of subsurface inflow on older formations on the south side of the basin* Field inspection of outcrops of the San Pedro formation reveals great regularity in bedding, and also considerable amounts of silt and clay. It can assumed that the upturned edge of the San Pedro is in hydrologic continuity th the aquifers in the same formation from which pumping occurs underlying th€ lley floor. Water level data and geologic control are not available for a liable estimate of subsurface inflow to the basin from th» outcrop. The ground water basin is depleted by pumped extractions, consumptive e of phreatophytes, effluent diseharge, and subsurface flow into Qxnard Forebay d Mound Basins. Subsurface Inflow and Outflow . Ground water movement into and out of nta Paula Basin was estimated by the rising water method. Sixteen second-feet s estimated as subsurface inflow from Fillmore Basin. Ten second-feet was timated as outflow into the Qxnard Forebay Basin. Additional subsurface out- ow also occurs into Mound Basin through the San Pedro formation and could ount to more than ten second-feet. Geologic data necessary for an accurate timate of subsurface outflow into Mound Basin are lacking. Ground Y/ater Storage Capacity and Specific Yield . Estimates of change storage are discussed in Chapter II. Some 67 well logs were used to obtain ese estimates. Weighted average specific yield of the sediments in the interval tween the water table elevations of 19l4i- and 1951 is estimated to be ten per nt. Change of storage in the outcrop area of the San Pedro formation could not determined because water level and well log data were unavailable. Such anges could conceivably be large. B-73 Using an. estimated area of 10.,000 acres and a depth of about 800 feet, total storage capacity of the ground water basin was estimated to be about 800,000 acre-feet. Additional storage capacity probably exists below this depth and in the outcrop area, but data, to estimate its amount are lacking. Yield of Wells . Irrigation wells in Santa Paula Basin yield from 300 to 1,5>00 gallons per minute and average about 700 gallons per minute. Mound Basin . i i • ' in - ' Mound Basin ranges in elevation from sea level to over I4OO feet and has a surface area of about 12,300 acres. It is bounded by hills to the north, Santa Paula Basin to the east, and Oxnard Plain and Oxnard Forebay Basins to the south. * . ■ » Geology . The principal water-bearing formation in Mound Basin is the San Pedro. Other formations include the overlying alluvial deposits and the unde- lying Santa Barbara formation. The Recent and upper Pleistocene alluvium is cha- racterized by yellow silty clay containing occasional lenses of sand and gravel. It varies from 100 feet to 5>00 feet in thickness. The yellow silty clay has beer deposited as alluvial fans by streams draining the area to the north. It appears that these yellow clays grade into and interfinger with deposits of Oxnard Plain Basin along the present course of the Santa Clara River. Gravel, sand, silt and clay of upper Pleistocene age outcrop along the north edge of the basin and dip southward as much as 12. degrees. These particular outcrops are at the base of the upper Pleistocene deposits and contain marine fossils which indicate littora] deposition. The San Pedro formation lies unconformably- beneath the alluvium and outcrops in the hills north of Mound Basin where it is U,000 feet thick. It consists of gravel, sand, silt, and clay. Marine fossils are found throughout tl B-7U gction of outcrop, out previous investigators believe that most of the upper f,rb of the San Pedro formation is continental in origin and that the marine fos- lis are reworked. The upper 500 to 1,000 feet of the San Pedro formation con- tins many permeable sand and gravel members. Below these members are a series I beds which are predominantly silts and clays and are in turn underlain by ;avels. The permeable members of the outcrop may be continuous with those be- nath the Mound Basin. Exposures show these sands and gravels to be extremely Inticular. Scour and fill features are common, and individual beds cannot be laced more than several hundred feet. From the outcrop, the San Pedro formation extends westward under the :.luvium of the Ventura River Valley and into the ocean. Contours of the ocean .oor indicate small irregularities which parallel the trend of the San Pedro ormation and suggest that it outcrops there. The San Pedro formation west of le Ventura River is mostly coarse gravel, with minor sands and clays. On the ist side of the Ventura River, however, the formation is mostly fine sand, silt id clay with only minor gravels. This rapid lateral change in lithology cannot lually be traced down the dip of the beds, but where suitable exposures are )und it appears that the down dip variations are as great as the lateral iiriations. The structure of Mound Basin is essentially that of a syncline as lown by cross-section B'-B", Plate B-1B. The San Pedro formation is folded in le Santa Clara River syncline and in the Montalvo anticline, and is displaced f the Saticoy fault (see Plate B-1B). The north limb of the Santa Clara River incline is exposed in the hills north of the basin. Well log data indicate that le Saticoy fault extends a short distance westward from Saticoy, but either dies it or cannot be detected westward from a point north of Montalvo. Water well ogs south of Ventura do not indicate that the Saticoy fault extends to the beachi lrface exposures and well logs indicate that complex folding and faulting has B-75 affected the area north of the Santa Clara River and south of the Saticoy fault. Cores from oil wells in and near the Santa Clara River west of Montalvo indicate that the south flank of the Santa Clara syncline dips steeply to the north. The Montalvo anticline in the area west of Montalvo appears to be assymetrical and probably overturned to the north. North and east of Montalvo the Montalvo anti- cline appears to be nearly symmetrical but is probably displaced by the Saticoy fault. An excavation on the small hill due north of Montalvo reportedly ex- posed sediments which dip sixty-five degrees southward. This outcrop is now covered, but the sediments in the area appear to be similar to the non-marine San Pedro formation. Cores from an oil well northwest of Montalvo indicate faults and steeply dipping sediments below 200 feet. These examples of faults and steeply dipping sediments are in themselves of little significance, since they cannot be correlated. They are important because they indicate that the water- bearing sediments in this part of Mound Basin have been involved in complex folding and faulting. Seaward Extension and Hydraulic Continuity of Aquifers With the Ocean . A question of some importance in Mound Basin is the possibility of hydrologic continuity of the aquifers of the San Pedro formation with the ocean. The only place where this continuity may exist is west of the Ventura River where the sou dipping beds strike westward into and beneath the ocean. Slope of the offshore topography is very gentle and it is unlikely that the San Pedro formation near the axis of the Santa Clara River syncline would outcrop on the ocean floor unles the syncline were folded upward. Offshore seismic data suggests that the synclin continues seaward without such upwarping. The gently sloping sea floor is under- lain by silty clay in areas where samples have been taken. B-76 "When water levels are high in Mound Basin, a seaward gradient exists, igesting subsurface outflow. Water levels fall below sea level during dry >iods, suggesting that sea water intrusion occurs. Detailed measurements of »ch wells and wells in and west of the Ventura River Valley perforated in the 3 Pedro formation show tidal fluctuations which lag behind the ocean tides by ty a few minutes. This short time lag indicates that the aquifer is affected jitidal loading but does not necessarily indicate hydraulic continuity with the :an. A shallow abandoned well near one of the City of Ventura's deep wells on ; beach showed more than an hour's time lag, indicating possible hydraulic :tinuity of the minor shallow aquifers with the ocean. Available evidence indicates, therefore, that outflow of fresh water or 'low of sea water is possible, but data are not available to estimate the quan- fy. Up to the time of writing this report no evidence of sea water intrusion i been found in quality of water from wells in the San Pedro formation which i closest to the ocean. Occurence of Ground Water . Vfells obtain water from sands and gravels ,the San Pedro formation and possibly from alluvium of upper Pleistocene age. has been necessary to drill water wells in Mound Basin to depths of I4.OO to >00 feet in order to obtain water from these gravels. The gravels of the 1 Pedro formation are overlain by up to 5>00 feet of confining silty clay, lis near the beach south of Ventura flow when water levels are high. Movement of Ground Water . Ground water in Mound Basin generally moves jtward toward the ocean as shown by the water level contours on Plates lli-B, -B, and 16-B. Movement may occur from Cxnard Forebay Basin as well as Santa lla Basin. Some movement may possibly occur from Gxnard Plain Basin and from J outcrop area of the San Pedro formation north of the Mound Basin. A water rel recorder installed on a well about 60 feet south of Highway 101 and just B-77 west of the Ventura River showed no fluctuations as a result of pumping a well about f>00 feet to the south, which has a drawdown of about 60 feet. Both wells are perforated, however, in the San Pedro formation which dips about 35 degrees southward in this vicinity. The lack of reaction in the recorder well indicates that there is limited movement of ground water across the bedding of the San Pedr formation. Replenishment and Depletion of Ground Water , Replenishment of Mound Basin occurs by subsurface inflow from adjacent basins and from the outcrop area of the San Pedro formation, which is in turn replenished by rainfall penetration and stream percolation. The basin is depleted by pumped extractions and possibly subsurface outflow. Subsurface Inflow and Outflow , Subsurface inflow occurs from Santa Paula Basin, from the outcrop area of the San Pedro formation and possibly from Oxnard Forebay and Oxnard Plain Basins when water levels are favorable. As dis- cussed in the paragraphs on Lower Ventura River Basin, inflow from the alluvium of that basin is probably negligible. Some subsurface inflow from the seaward extension of the aquifers probably occurs during periods of low water level. Subsurface outflow from Mound Basin into Oxnard Plain Basin may occur through the San Pedro formation beneath Oxnard Plain Basin when water levels are suitable, but the degree of hydrologic continuity of the San Pedro formation between these two areas is uncertain and may be negligible. Some subsurface out- flow toward the ocean may occur during periods of high water level. Ground Water Storage Capacity and Specific Yield, It is estimated that very little, or no change of storage occurs within Mound Basin, Sine* water leve and well log data are lacking in the outcrop area, change in storage in the San Pedro formation north of the basin could not be estimated, although such changes may be fairly large. B-78 Yield of Wells . Wells in Mound Basin yield from 300 to 1,500 gallons ! minute from the San Pedro formation. The estimated average yield is 700 ions per minute and the average specific capacity about 70. :a rd Forebay Basin Ground surface elevations within Oxnard Forebay Basin vary from about to 15Q feet above sea level and the basin occupies an area of about 6,170 acres, water-bearing sediments of Oxnard Forebay Basin are similar in several respects those of Oxnard Plain Basin except that the Oxnard Forebay is a free ground er area. This basic difference is so important that the areas have been ferentiated and will be described separately. Geology . Formations in Oxnard Forebay Basin include Recent and upper istocene alluvium underlain unconf ormably by the San Pedro formation and, in mall area, by the Santa Barbara formation. Alluvium of Recent and upper Pleistocene age is the most important mater- in the Oxnard Forebay since it forms the ground water reservoir for most of water used in Oxnard Plain Basin. The alluvium consists of up to about iiOO t of river deposited gravels, clays and sand being common below 200 feet, alluvium has been deposited unconf ormably upon the upturned San Pedro and ta Barbara formations. Geologic Section K-K', Plate 12-B, shows that the base the upper Pleistocene has also been folded, while the upper gravels have not n appreciably disturbed, resulting in a local unconformity within the materials e designated alluvium. This interpretation of the data would suggest that some the lower part of "upper Pleistocene" alluvium may be middle Pleistocene in age, ce parts of it would have been deposited while the unconformity was being formed the middle Pleistocene orogenyj or the lower part of the alluvium is in reality I. jer Pleistocene in age, and folding has occurred in upper Pleistocene tine. The B-79 latter possibility is preferred, since upper Pleistocene vertebrate fossils have been found near Ventura in the terrace deposits which dip 10 to 15> degrees south- ward. It is probable that the sediments are still being actively folded. The upper gravels are continuous with the Oxnard aquifers of Oxnard Plain Basin. The gravels are poorly sorted and consist of cobbles and pebbles of sandstone, conglomerate, and igneous rock. They occur in a matrix of medium to coarse sand and contain small, irregular beds of silt and clay. Oxnard Forebay Basin is the apex of the large Oxnard Plain alluvial fan where the coarser mate- rials are found. The nature of the clay capping the oxnard aquifer in Oxnard Plain Basin as it approaches Oxnard Forebay Basin is rather complex, as might be expected. In general, the clay cap interfingers with the gravels of the Forebay, the percentage of clay decreasing to zero in the Forebay. The bottom and top of the clay cap also slope downward away from the Forebay. As a result of the slope of the bottom of the cap and the interfingering with gravels, the actual contact o the free water surface with the clay cap will vary over a wide zone depending on the water levels in the Forebay. The San Pedro formation underlies the alluvium unconformably, as shown in Section K-K', Plate 12-B, but appears to become conformable near the south and west edges of Oxnard Forebay Basin. A medium to coarse grained sand is found near or at the base of the San Pedro formation. This sand is the equivalent of the Fox Canyon member in West Las Posas Basin. The surface outcrop of the Fox Canyon | member on the south slope of South Mountain continues westward into Oxnard Forebay Basin. Its outline beneath the alluvium has been traced by the use of water and oil well logs and by inspection of materials from wells drilled during this investigation. The probable extent of the Fox Canyon member is shown on the geologic map (Plate B-1B). The Fox Canyon is folded into a westward plunging anticline, the anticlinal structure of which is confirmed by deeper oil well logs. A few oil well logs indicate that the Fox Canyon member of the San Pedro formation B-80 ^continuous into and beneath Oxnard Plain Basin, although areas of low per- ebility may exist which could retard flow of water toward Oxnard Plain Basin. The nature of the San Pedro formation above the Fox Canyon member and bow the upper Pleistocene alluvium is not well known. Available oil well logs ricate that other permeable beds exist above the Fox Canyon member and possibly rerlie unconformably the alluvial gravels of the Forebay. These aquifers in b San Pedro formation cannot be traced by well logs into Mound Basin, but there e: be some continuous beds since water levels can be contoured into Mound Basin un the west end of Oxnard Forebay Basin. The oldest formation of interest is the Santa Barbara formation of lower dstocene and upper Pliocene age which consists of impervious clay and silt. .3 formation underlies the San Pedro formation and both have been folded and i'tially removed by erosion in Oxnard Forebay Basin prior to deposition of .uvium. As a result of this folding and erosion, the Santa Barbara formation r lies immediately under the alluvium in the area between the Saticoy spreading bunds and the westernmost exposures of the formation on Oak Ridge. Several well ;s indicate that the depth to the eroded surface of the Santa Barbara formation irages about 75 feet but ranges up to lUO feet. The Saticoy fault separates Oxnard Forebay Basin from Santa Paula Basin. i exact location of the fault beneath the Santa Clara River east of Saticoy is mown, hence the boundary there is arbitrary, but is guided by the point where :face water from Santa Paula Basin begins to percolate into the river gravels. J boundary between Oxnard Forebay Basin and Mound Basin is also somewhat arbi- iry and has been placed along the north edge of the Santa Clara River, where LI logs indicate the approximate limit of the permeable gravels of the alluvium. 3 boundary between Oxnard Forebay Basin and Oxnard Plain Basin has been estab- 3hed from well logs and is the probable limit of the area where rainfall penetra- on and excess applied irrigation water returns to the aquifer. This does not B-81 necessarily coincide with the actual pressure-nonpressure boundary which has been discussed above. Occurrence of Ground Water . Ground water occurs in the Recent and upper Pleistocene alluvium and in permeable sands and gravels of the San Pedro formation. Oxnard Forebay Basin is essentially a free ground water area, with changes of water level and corresponding changes in ground water storage occurri: in the alluvium. Apparently, the permeable zones in the San Pedro formation underlie and are in hydrologic continuity with the alluvium. The Santa Barbara formation underlying the San Pedro consists of fine silt and clay and is general 1 impervious • Movement of Ground Water . Ground water moves southwesterly in Oxnard Forebay Basin toward Oxnard Plain Basin as shown on the water level contour maps (see Plates lh-B, 15-B, and 16-B). The shape of the water table contours in the upper portion of the Forebay resemble those of a ground water mound produced by an injection well. The Saticoy fault and the eastern boundary of Oxnard Plain Basin near the Forebay may be visualized as enclosing a segment of a circle. Slope of the water table decreases away from the apex in much the same way the hydraulic gradient decreases away from an injection well. A difference in eleva tion of 50 to 100 feet occurs across the Saticoy fault in a distance as short as 500 feet. Movement of water into Oxnard Plain Basin may be complex when water levels in Oxnard Forebay Basin are low. For example, when the westerly end of the Forebay has been lowered greatly by pumping, some water may leave the upper part of the Forebay, where water levels are high, and move into the area just south of the spreading ground, then back into the Forebay in the vicinity of the junction of Highways 101 and 101A. B-82 Replenishment and Depletion of Ground Water . Qxnard Forebay Basin is rplenished by subsurface inflow, by percolation in the Santa Clara River channel jid in the Saticoy spreading grounds, and by percolation of direct precipitation ad the unconsumed portion of water applied for irrigation and other uses. The brebay is depleted by subsurface outflow, pumped extractions, and probably by •'fluent discharge over the clay cap and consuptive use of phreatophytes during ;$riods of high water level. Subsurface Inflow and Outflow . Subsurface inflow occurs from Santa aula Basin through and possibly over the Saticoy fault. Some subsurface inflow iy occur from Mound Basin when water levels there are higher than in the Forebay. absurface outflow occurs into Oxnard Plain Basin through the aquifers of the iluvium and San Pedro formation. Subsurface outflow into Pleasant Valley Basin ossibly occurs through the aquifers of the San Pedro formation, primarily irough the Fox Canyon member. Some subsurface outflow into Mound Basin probably scurs at various times through the San Pedro formation in the area near Montalvo. len water levels in the Forebay are above the clay cap of Oxnard Plain Basin, ome subsurface outflow may occur into the semi-perched zone overlying the clay ap. Ground Water Storage Capacity and Specific Yield . Estimated changes of torage in Oxnard Forebay Basin are discussed in Chapter II. Estimated weighted ean specific yield of sediments between the interval of the 19hh and 1951 water evels is 16 per cent. Estimated total storage capacity of the alluvium in xnard Forebay Basin is about 300,000 acre-feet. When water levels are lowered n Oxnard Forebay Basin, water levels also drop in Oxnard Plain Basin. If water evels were drawn down so the Oxnard aquifers were entirely dewatered, then total torage of the Oxnard aquifer in Oxnard Plain and Oxnard Forebay Basins is pro- ably on the order of 800,000 acre-feet. B-83 Yield of Wells * Irrigation wells in the Gxnard Forebay Basin yield frc 200 to 2,000 gallons per minute, the average being of about 1,100 gallons per minute. Specific capacity. of wells averages about 200. Oxnard Plain Basin The Oxnard Plain Basin ranges from sea level to about 100 feet in ele- vation, and occupies an area of about u6,U60 acres. Included in the basin is about one-fourth of the irrigated area of Ventura County, This basin is boundec on the west by the Pacific Ocean, on the north by Mound Basin, and on the east by West Las Posas and Pleasant Valley Basins, The boundary between Oxnard Plaii and Mound Basins is arbitrarily placed along the Santa Clara River, Geology , Y/ater-bearing formations in Oxnard Plain Basin include alluvium of Recent and upper Pleistocene age, the San Pedro formation of ^Lower Pleistocene age> and to a minor extent the Santa Barbara formation of lower Ple> tocene and upper Pliocene age. Formations underlying .the Santa Barbara are pew trated only by oil wells and include the Pico, "Santa Margarita", Modelo, Topanj, and Sespe formations as well as volcanic rocks of Miocene age. The principal aquifers underlying Oxnard Plain Basin are shown on Geologic Sections K-K' and M-M', Plate 12-B, The most important aquifer under- lying Oxnard Plain Basin is the Oxnard aquifer, which is part of the upper Pleistocene alluvium. The Oxnard aquifer is a series of river deposited gravel; and is continuous with gravels in Oxnard Forebay Basin. The east and northwest boundaries of Oxnard Plain Basin coincide with the extent of the Oxnard aquifer The Oxnard aquifer is characterized by medium to coarse gravel interbedded with lenticular deposits of coarse sand and some clay streaks. Well logs indicate considerable irregularity in areal extent and thickness of clay and sand lenses, as would be expected of river deposits. The Oxnard aquifer is capped by yellow B-8U ad blue clay and silt, the base of which ranges in elevation from sea level nar the forebay to about 130 feet below sea level near the coast. The overlying cay cap varies from 50 to 15>0 feet in thickness, and well logs indicate that it cntains lenticular sands and gravels, which causes some increase in permeability c the cap. The clay cap is overlain by up to $0 feet of sand and gravel, which etends to the ground surface. These permeable sediments contain semi-perched gound water and are considered to be of Recent age. The boundary between Gxnard Forebay and Oxnard Plain Basins is placed, a noted above, to include in Oxnard Plain Basin the area where applied water des not return to the principal aquifers. As also stated, above, the pressure- rnpressure line coincides with the intersection of the unconfined water table wth the base of the confining clay cap, which intersection shifts laterally as urter levels in Oxnard Forebay Basin fluctuate. The base of the Oxnard aquifer is rather poorly defined since most vster wells do not penetrate more than a foot or two of clay below the gravel. I some cases, this basal clay may be only five or six feet thick and additional gavels may be beneath. In general, however, the Oxnard aquifer is about 75 to 20 feet in thickness, and the base varies in elevation from 180 feet to 2£0 feet tlow sea level. Well log control of the sediments below the Oxnard aquifer is poor. Mailable logs indicate that the base of the upper Pleistocene sediments is about 10 to 500 feet below the surface (about 200 to 300 feet below the Oxnard aquifer) sd that other aquifers of unknown areal extent and hydrologic continuity exist. I the southeast portion of Oxnard Plain Basin, a fairly continuous gravel sratum about 70 feet in thickness occurs at depths of i;00 feet and extends at B-85 least partly into Pleasant Valley Basin. Scattered well logs in other parts of Oxnard Plain Basin also indicate gravels at this depth. Near the City of Port Hueneme, however, a 600 foot water well penetrated only fine silt and clay from 300 to 600 feet, indicating that the UOO foot gravels do not underlie the entire Oxnard Plain Basin. The Recent and upper Pleistocene alluvium is underlain by the San Pedr< formation which varies from about 600 feet in thickness in the southern part of the Oxnard Plain to about 1,800 feet just south of the Santa Clara River. Only two water wells on the Oxnard Plain are known to completely penetrate the San Pedro formation. Several oil wells also penetrate it, but logs of these wells ai generally poor. From a study of the available oil well logs, electric logs, and water well logs, it appears that the basal 100 to 300 feet of the San Pedro forma- tion consists of sand and some gravel which is most likely continuous with the F< Canyon aquifer in Pleasant Valley and West Las Posas Basins and is a potentially important aquifer in Oxnard Plain Basin. Electric logs of oil wells in the Oxnai oil field, about four miles due east of the City of Oxnard, indicate that the Fo: Canyon member consists of a series of sands containing irregular interbedded sil and clay layers. Fossils indicating shallow marine or lagoonal conditions of de- position have been found in the few wells which have been inspected by geologist; during drilling. Oil well logs suggest a thickening of the Fox Canyon northward toward the Santa Clara River, but it is extremely difficult to determine whether this member continues into Hound Basin. Some electric logs suggest that the bas*. part of the San Pedro formation near the Santa Clara River may contain water of poor quality. All sources of information indicate that sands and gravels occur :. the San Pedro formation above the basal Fox Canyon member. The degree of hydro- logic continuity of these additional pervious zones with areas of recharge, or vM the Fox Canyon member, cannot presently be determined. B-86 The Santa Barbara formation underlies the San Pedro formation in the jjiard Plain and varies from about 2,000 feet in thickness near the Santa Clara FH'er to about 800 feet in the southern part of the area. Electric logs of two Wc!;er wells near Port Hueneme and Mugu Lagoon indicate that thick permeable zones w exist here and also that the lower half or two-thirds of the formation proba- d> contains water of poor quality. Electric logs in the Oxnard oil field area iriicate fairly fresh or slightly brackish water in the formation, while electric lis in the Santa Clara River area indicate that nearly all the Santa Barbara pro- bJ)ly contains water of poor quality. These electric logs also indicate that the Sata Barbara formation contains few permeable zones near the Oxnard oil field ail the Santa Clara River areas. The outcrop of the Santa Barbara formation on tb south slope of Oak Ridge adjacent to this basin similarly contains few per- nibble zones. Structure of Oxnard Plain Basin is relatively simple * The water-bearing imperials are generally nearly flat lying, and are not known to be affected by fill ting. Total thickness of alluvium and the San Pedro formation- south of the SJita Clara River is about 2,000 feet, while north of the river in the Santa Clara Rjrer syncline the total thickness is over h,000 feet. See Geologic Section B-B", Jpe B-1B, for structure of the area. Seaward Extension and Hydraulic Continuity of Aquif ers With the Ocean . Tjj relationship of the Oxnard and Fox Canyon aquifers with the offshore topo- giphy and geology is of considerable interest in arriving at an understanding of t.3 ground water hydrology of Oxnard Plain, Oxnard Forebay, and Pleasant Valley Bsins. The pertinent submarine topographic features are discussed in Chapter B!I and are shown on Plate B-3. It is apparent that both the Oxnard and Fox Canyon aquifers extend for sie unknown distance seaward beneath the ocean as illustrated by Geologic Sec- tttis K-K» and M-M» on Plate 12-B. B-87 The seaward extension of the aquifers presents two important problems in the consideration of the ground water hydrology of the Qxnard Plain Basin, While data are lacking in many respects, the operation of the ground water basins is partly dependent on the conditions seaward of the coastline. The two problems are that the aquifers may outcrop at some unknown distance seaward on the ocean floor resulting in hydraulic continuity of the ground water with sea water, and that the seaward extension of these aquifers may act as ground water storage rese. voirs not inventoried in the hydrologic study whose utilization is dependent on ti seaward distance of the outcrop. Seaward extend of the Qxnard aquifer is unknown, though the presence of two sharply defined submarine canyons a short distance southerly of the coastline offers reasonable possibilities for the outcropping of the aquifer close to shore thereby limiting utilization of the storage capacity, at least in the vicinity of the canyons. Evidence suggesting that the Qxnard aquifer outcrops in the vicinit of the head of Hueneme Canyon includes the following: (1) the development of a landward gradient during periods of low water levels of the piezometric surface near Port Hueneme, the contours having a roughly circular shape with the canyon i the center, (2) historic reports of fresh water outflow in the Hueneme Canyon at times of high water levels, (3) fluctuations of water levels in wells correspcd ing to but lagging up to three hours behind tidal fluctuations, and (U) water qu; ity indicating possible sea-water intrusion in 19E>1 near Port Hueneme. The only- indications for seaward extension of the Qxnard aquifer or connection with the o-B, and 16-B). When Oxnard Forebay Basin is filled as in 19lih, water moves southwestwari from the Forebay toward Hueneme and Mugu Canyons. When the water levels are low ered in the Forebay by pumping in Oxnard Plain and Oxnard Forebay Basins, the hy- draulic gradient toward the ocean decreases until no outflow to the ocean occurs Further pumping on Oxnard Plain Basin or further lowering of the Forebay causes landward hydraulic gradient with a resultant landward movement of water in the s-i- ward extension of the aquifer. When the landward gradient occurs, a trough is formed. The formation of the trough will depend on elevation of the water table in Oxnard Forebay Basin and the amount of pumping in the Oxnard Plain Basin. De tailed water level contours indicate that the position of the trough axis approxi- mates the shape of tx-jo circular segments with Hueneme and Mugu Canyons as center of the circles. The position of the trough axis varies seasonally as pumping rates and water levels in Oxnard Forebay Basin change. The trough position in ti B-90 \ ml of 19^1 is shown on Plate 16-B, along with the area in x^hich water levels ybe below sea level. Movement of ground irater in the Fox Canyon aquifer is not well known ooause few water wells are drilled into it and water level data are largely lack- tl. From available evidence it appears that water in the Fox Canyon aquifer mves from Qxnard Forebay Basin toward the southern portion of Cxnard Plain Basin, vfen pumping occurs in Pleasant Valley Basin, ground water in the Fox Canyon aluifer moves eastward from Oxnard Plain Basin into Pleasant Valley Basin, as sDwn on Plate 16-B. In the southeast portion of Oxnard Plain Basin there are a few wells wich are perforated in both the Oxnard and Fox Canyon aquifers, and water levels apear to be nearly the same in the two aquifers. Replenishment and Depletion of Ground Water . Oxnard Plain Basin is rplenished by subsurface inflow from Oxnard Forebay and from the ocean side of te trough during periods of low water levels. It is possible that a minor sount of water is supplied to the Oxnard aquifer during periods of low water Ivel by compaction of overlying clays. Appreciable leakage may occur through ie clay from the semi-perched zone into the Oxnard aquifer, but its amount culd not be estimated because of the considerable time and expense required. No hdrologic evidence is available to show that leakage does occur through the clay cp, but well logs consistently indicate that this cap contains irregular inter- tdded lenses of gravel and sand, and it is therefore conceivable that leakage culd occur. Extractions from Oxnard Plain include pumping and, during periods of Igh water levels, outflow to the ocean aid effluent discharge through uncapped nils. It is probable that some water is lost by leakage through the clay cap i.en the piezometric surface of the Oxnard aquifer is higher than the water table If the semi-perched ground water body. B-91 It is also possible that an unknown amount of water is transferred be- tween Qxnard Plain Basin and Mount Basin through the San Pedro formation. Subsurface Inflow and Outflow . Subsurface inflow and outflow is dis- cussed above. Ground Water Storage Capacity . Since the aquifers in Qxnard Plain Basi are confined, there is essentially no change in storage except that resulting frc compaction of overlying clays. Such change of storage is probably negligible. The base of the clay which caps the Oxnard aquifer in general slopes oceanward as shown on Geologic Section K-K 1 , Plate 12-B, and the diagrammatic sketch on Plate 13. Therefore, the line of intersection of the water table with the base of the clay cap shifts laterally with varying water levels in Oxnard Forebay Basin resid- ing in change of storage in the area defined as Oxnard Plain Basin. For conveni- ence, such change of storage has been included with that in Oxnard Forebay Basin, It is estimated that the total storage capacity of that portion of the Oxnard aquifer within Oxnard Plain Basin, if it could be dewatered, would be aboi £00,000 acre -feet, and that the capacity of the Fox Canyon aquifer is probably tt same. Yield of Wells , Water wells in Qxnard Plain Basin yield from 300 to 2,300 gallons per minute and have an estimated average yield of about 900 gallom per minute and an average specific capacity of about 70. B-92 P easant Valley Basin Pleasant Valley Basin has been divided in prior reports into pressure ad non-pressure areas. It is considered in its entirety as a pressure area in tis report for reasons discussed below. This basin consists of about 23,850 ares and is second only to Oxnard Plain Basin in irrigated acreage. It ranges i elevation from about 1$ to over 2^0 feet above sea level. Geology . Many aspects of the geology and ground water hydrology in Feasant Valley Basin are not clearly understood; faulting, folding, rapid thin- rng of formations, multiple perforations of individual wells, and lack of adequate Igging and inspection of wells during drilling make an interpretation of the gology of the area difficult. The water-bearing formations in Pleasant Valley Basin include alluvium Recent and upper Pleistocene age, and the marine San Pedro and Santa Barbara rmations. These formations are underlain by the Pico and "Santa Margarita" Irmations, Modelo shale, and volcanics of Miocene age. The volcanic rocks out- cop in the Santa Monica Mountains on the southeast side of Pleasant Valley Basin. In general, there are two areas in Pleasant Valley Basin where aquifers i\ alluvium of Recent and upper Pleistocene age are utilized. One area is north <* the Camarillo fault and south of the Camarillo Hills, the other is south of the (imarillo fault in the east and southeast portion of the basin. The aquifers in 'iese areas do not appear to be connected with the Oxnard aquifer in Oxnard Plain Jisin. Alluvium north of the Camarillo fault reaches a thickness of ij.00 feet and insists of grey sand, gravel, and yellow and blue clay deposited in alluvial fans v Arroyo Las Posas and by other smaller creeks. The sands and gravels are lickest to the north and appear to pinch out toward the south. The alluvium mth of the Camarillo fault is about UOO feet thick and is mostly clay with ir- jgular interbedded sands and gravels. Sands and gravels are predominant in le easterly portion of Pleasant Valley Basin and appear to thin out westward B-93 from the area south of the town of Camarillo into the west central portion of thi: basin. The San Pedro formation underlies all Pleasant Valley Basin and consist; of from U00 to l,f>00 feet of gravels, sands and clays. The most important aquife: in Pleasant Valley Basin is the basal Fox Canyon member which consists of sand an' gravel. Thickness of the Fox Canyon aquifer varies from 100 feet near Santa Rosa Valley to 300 feet in most of the area. The Fox Canyon aquifer can be easily traced by well logs over all but the eastern corner of the basin, where there are few logs of deep wells. It is possible that the Fox Canyon aquifer is connected by interbedded gravels with the shallower sands and gravels of the alluvium in th eastern portion of Pleasant Valley. The Fox Canyon aquifer is underlain by the Santa Barbara formation, whii consists of sand, clay, and some gravel and varies in thickness from $0 feet near Somis to over 900 feet at the west border of the area. The Santa Barbara formatin is reached by few water wells in Pleasant Valley Basin. It is possible that the equivalent of the Grimes Canyon member in East Las Posas Basin is present in Pleasant Valley Basin near the top of the Santa Barbara formation as shown on Geologic Sections L-L' and M-M', Plate 12-B. The Grimes Canyon aquifer consists of up to 300 feet of loose, coarse gravel and sand. The volcanic rocks which are adjacent to and underlie the southern por- tion of Pleasant Valley Basin yield water to wells from fractures and from grave! interbedded with the volcanic flows. Most wells drilled into the volcanics also obtain water from overlying gravels of the alluvium or San Pedro formation. Structural features of Pleasant Valley Basin include at least two east wegt trending faults and associated folds in the northern portion of the area. The faults and folds appear to die out westward into the Oxnard Plain. These ' structural features are the Camarillo Hills and Springville anticlines, the Spri$- ville fault zone, the Camarillo fault, and a snycline and anticline between thes faults . B-9li The Springville fault zone (see Plate B-1B) is up to 1,000 feet wide and cisists of two major and probably other minor faults which parallel the south edge o the Camarillo Hills. The major faults of this zone are well exposed in portions i 0; the Camarillo Hills. Several exposures along one of these faults show that it i turn consists of a complex zone up to 100 feet wide with highly folded sediments i eluded between lesser faults. The principal fracture occurs in a zone of crushed siiments varying from a foot to several feet in width. The Camarillo fault can be detected in water well logs where displacement c ; aquifers may be noted. It also has effected older alluvium and can be traced fci surficial features. The folds between the Camarillo fault and the Springville fault zone ensist of an east-west trending anticline just north of the Camarillo fault, and ssyncline farther north. These folds can be traced from well log data and surface cj.tcrops of older alluvium near Camarillo. The gentle synclinal fold between the Cmarillo fault and the Santa Monica Mountains can be detected from well logs. The Fox Canyon aquifer is folded in the Camarillo Hills anticline so iiat the top of it is exposed near Somis, as shown on Geologic Section L-L 1 , Late 12 -B. The Fox Canyon aquifer is displaced by the Springville fault zone j.ong the south side of the Camarillo Hills and also by the Camarillo fault. Well logs indicate that the Fox Canyon aquifer lies unconformably on the volcanic rocks i.ong the south side of the Pleasant Valley Basin but does not outcrop there. It "iiins eastward, north of the Camarillo fault, into the Santa Rosa Basin where it \nches out. Occurrence of Ground Water . Ground water occurs in sands and gravels of le alluvium and of the San Pedro formation, as well as in the fractured volcanics. round water in the basin is essentially confined. However, the Fox Canyon member 3 unconfined in a limited area near Somis. Some of the very shallow sands and B-95 gravels around the north and southeast sides of the area may be unconfined, but available well logs indicate the shallow sands and gravels to be underlain by thick clays which probably prevent appreciable amounts of surface water from reac] ing the major aquifers. M ovement of Ground Water * Ground water moves toward the center of Pleasant Valley Basin during periods of heavy draft. When water levels are high the ground water generally moves in a southerly direction. Plates lii-B, 15-B, an 16-B show water level elevation contours of the two principal aquifers in this basin. Replenishment and Depletion of Ground Water . Pleasant Valley Basin is replenished principally by subsurface inflow from East Las Posas Basin near SomiE and from Oxnard Plain Basin through the Fox Canyon Aquifer. Replenishment of smaller magnitude also occurs by subsurface inflow from Santa Rosa Basin through the San Pedro formation, from West Las Posas Basin through the Springville fault zone; and from the volcanics to the south and southwest of the basin. Ground wair from Pleasant Valley Basin is depleted by pumped extractions and possibly by sub- surface outflow toward the ocean during periods of high water level. Subsurface Inflow and Outflow . Nearly all ground water used in Pleasa: Valley Basin is supplied by subsurface inflow from the following sources: (1) From the ocean and Oxnard Forebay Basin through the Fox Canyon aquifer under Oxnard Plain Basin; (2) From East and West Las Posas Basins through the Fox Canyon aquifer near Somis and across the Springville fault zone; (3) From Sant Rosa Valley through the San Pedro formation; (U) From the fractured volcanics into overlying and adjacent shallow aquifers and the Fox Canyon aquifer. Subsurface outflow toward the ocean may occur during periods of high water level. B-96 Ground Water Storage Capacity . Negligible change of storage occurs in te little used shallow sands and gravels and in the confined aquifers. It is lkely that some change of storage has occurred in the volcanic rocks, but data ae not available to make an estimate of this change. Similarly, data are lacking fr an estimate of total storage capacity of the basin, although it is probably o the order of magnitude of the storage capacity of Oxnard Plain Basin. Yield of Wells . In general, the wells which are perforated in the Fox Cnyon aquifer yield the greatest amounts of water. The maximum is about 2,1*00 gllons per minute and the average about 1,000 gallons per minute with a drawdown c' about 10 to $0 feet. Wells perforated in both volcanic rocks and shallower £|uifers or in shallower aquifers only generally yield up to 1,000 gallons per unute, the average being about I4OO gallons per minute and the drawdown 30 to 70 .^et. B-97 Ground Water Basins Within the Calleguas-Conejo Hydrologic Unit The ground water basins of the Calleguas-Conejo Hydrologic Unit includ Simi, East and West Las Posas, Conejo, Tierra Rejada, and Santa Rosa Basins, Si. Basin is the only basin in this hydrologic unit which is essentially a simple al luvial filled type. The others are complex and consist of two or more formation which are folded and faulted. Geologic features of this unit are shown on Plate B-1C, and certain physical characteristics are summarized in Table 16 of Chapter II. Simi Basin Simi Basin, comprising an area of about 10,760 acres, underlies the alluvial area of Simi Valley in the extreme east central portion of the CallegUc- Conejo Hydrologic Unit. The floor of Simi Valley is formed by coalescing alluv:l fans emanating from Tapo Creek and other canyons. Surface elevation ranges froi 700 feet at the western end of the valley to 1,100 feet near the apex of the Ta; Creek cone. A maximum surface elevation of 3,117 feet is attained on the drain/e divide in the Santa Susana Mountains to the north. Geology . Geologic formations in the Simi Valley area may be divided into permeable alluvium of Recent and Fleistocene age and older semi-permeable formations. The folded Santa Barbara formation forms a ground water basin in t Tapo Canyon area which is separated from the alluvial filled Simi Valley by sen permeable older formations. Semi-permeable formations include the volcanics, Sespe, upper and lower Llajas, Santa Susana-Martinez, and sandstones of CretacecJ age. Of these semi-permeable formations, the Sespe, lower Llajas, and Cretacec formations yield some water to wells in the hills on the south and southeast s: of Simi Valley. Ground water in some of these formations appears to be of poor quality, especially at depths of more than 300 or 400 feet. B-98 Alluvium in Simi Basin consists of stream deposited gravel, sand, and ly up to 730 feet thick. The base of the alluvium is bowl-shaped and tapers upard to its edges. It is underlain and flanked by the older formations men- tioned above. The alluvium has a high clay content in the west end of the valley, hre it locally confines the underlying gravels. Elsewhere in Simi Basin the clys are lenticular and quite irregular. The older formations in the hills surrounding Simi Valley form a syn- clne which plunges gently westward. The syncline is cut off on the north side oithe valley by the Simi fault. In the Tapo Canyon area about three miles north of Simi Basin, the Santa Brbara formation of Plio-Pleistocene age is exposed. It consists of marine and cutinental gravels, sands, and clays, all of which have been folded into a tight s;icline by southward thrusting of the Santa Susana fault. The Santa Barbara for- nuiion is over 1,000 feet thick in this area. Although some of the deep alluvium ii Simi Basin may be equivalent to part of the Santa Barbara formation, the two a:i not in hydrologic continuity as they are separated by the semi-permeable for- mations north of Simi Valley. Occurrence of Ground Water . Ground water occurs in the alluvial fill of S'ni Valley and in interstices and fractures of the older formations that flank t3 valley. The alluvial fill constitutes the principal aquifer and underlies the aaa of Simi Basin. Second in importance is the isolated area of the Santa Erbara formation which yields water from permeable sand and gravel members in the Mcinity of Tapo Canyon. In cross-section the alluvium of Simi Basin is shown to be shallow near te perimeter of the basin and to increase in thickness toward the center (Sec- ions Q-Q» and R-R' , Plate 12 -C) where it exceeds 700 feet. Near the westerly extremity of the valley the alluvium at shallow depth cntains considerable clay and silt. These fine materials serve to locally B-99 confine ground water. In periods of high water level, wells that penetrate be- neath these materials have flowed. However, unconfined conditions predominate ii Simi Basin. Movement of Ground Water . Ground water in the alluvium of Simi Valley moves westerly except in dry periods when wells are heavily pumped (see Plates lli-C, l£-C, and l6-C). During such periods a depression forms in the central portion of the basin and the ground water converges on this low area. Ground water in the older semi-permeable formations moves in general toward the valley fill. In the eastern portion of Simi Valley water levels in wells in alluvium are generally lower than water levels in wells perforated only in the underlying older formations. Replenishment and Depletion of Ground Water . Ground water in Simi Basi is replenished by percolation of direct precipitation, stream flow, and the uncc- sumed portion of water applied for irrigation and other uses. Additional source of replenishment are artificial spreading and a minor amount of subsurface infl from older formations. Ground water in the older semi-permeable formations and in the Santa Barbara formation in the Tapo Canyon area is replenished by rainfa] penetration and stream percolation. The alluvial basin is depleted by pumped extractions , consumptive use phreatophytes, effluent discharge and subsurface outflow. The semi -permeable f< mations are depleted by evapo-transpiration, pumping, by outflow through spring; during periods of high water level, and by subsurface outflow into the alluvium The Santa Barbara formation is depleted by spring discharge and by pumping of water for export to Simi Valley. Subsurface Inflow and Outflow . Subsurface inflow enters the alluvial fill of Simi Basin from adjacent older formations, but no subsurface inflow is known to enter this hydrologic subunit from other subunits. Subsurface outflow B-100 ]aves Simi Valley through the Arroyo Simi where the alluvium appears to be only () to 100 feet thick and about 1,000 feet wide, and enters East Las Posas Basin, hbsurface flow out of Simi Valley through this alluvium has been estimated by tie slope-area method to be about 100 acre-feet per year. During periods of low inter levels, it is possible that subsurface outflow becomes negligible. Ground Water Storage Capacity and Specific Yield . Estimates of change T storage in the alluvium of Simi Basin are discussed in Chapter II. Estimated lighted mean specific yield of alluvial sediments in Simi Basin is 8.6 per cent. r )tal storage capacity of the alluvium below high water level of 1929 was estima- +*d to be about 180,000 acre-feet. Storage above this level was estimated to be oout 40,000 acre-feet. Yield of Wells . Wells in the alluvium of Simi Valley yield an average c about 400 gallons per minute. An exceptional well in Cretaceous sandstone is ^ported to yield 1,200 gallons per minute »but most of the wells in the older jcks yield about 100 gallons per minute. Wells in the Santa Barbara formation in " he Tapo Canyon area have an average yield of about 100 gallons per minute. Artificial Spreading of Water as a Means of Basin Replenishment . Stu- ies of the Soil Conservation Service and the Division of Water Resources indicate ne most suitable locations for major spreading works on alluvium are situated ear the mouth of Tapo Canyon, along Chivo Creek* and along Arroyo Simi just west f Santa Susana. The Tapo Creek location provides greater available ground water torage than does the Arroyo Simi location, but infiltration rates at this site are nferior. The Chivo Creek area appears to have least available storage but infil- ration rates are suitable. Before any particular site is chosen here or in any ther area for large scale spreading, exploratory test wells should be drilled and ilot spreading operations conducted to insure success . B-101 East Las Posas Basin East and West Las Posas Basins are geologically similar in some respect but differences are great enough that they can be described separately. East Las Posas Basin comprises about 36,370 acres and is located within the East Las Posas subunit. It is bounded by nonwater-bearing formations which are adjacent to the basin on the south slope of Oak Ridge, in the Happy Camp Canyon area, and in the Las Posas Hills. The western boundary is the surface drainage divide between Eas and West Las Posas Basins. Near Somis the boundary was arbitrarily placed acrosj the narrowest part of the southwesterly-trending valley through that town. Elevf tion of the drainage area ranges from about 2$0 feet near Somis to about 2,800 fit on Oak Ridge. Geology . East Las Posas Basin is a broad east-west trending valley be tween Oak Ridge and the hills on the south and is presently undergoing stream di section. The principal water-bearing materials of the basin are Recent and upp Pleistocene alluvium and the San Pedro and Santa Barbara formations. Semi-perme able older formations adjacent to and underlying the water-bearing formations include the Sespe, Vaqueros, Modelo, and Pico formations, as well as limited are of volcanic rocks. Most of these older formations contain water of poor quality but good water has been obtained from sandstones and conflomerates of the Sespe formation. Late Quaternary alluvium occurs as fill in most of the valleys of t basin. The thickest, most extensive, and most important alluviated area is in i4 vicinity of Moorpark, where the alluvium consists principally of up to 200 feet i sand and gravel and underlies about 5>,100 acres. Near Somis the alluvium is o; UO to 80 feet thick, and consists of silts and clays. In the smaller valleys, alluvium generally varies up to J4O feet in thickness and consists of silt and sad with some clay and gravel. 1 , I B-102 ; Previous workers have called the youngest of the pre-alluvial sediments ;errace deposits". Since most of these deposits are folded and since it is ex- remely difficult to differentiate them from the underlying San Pedro formation pey are considered in this report as part of the San Pedro formation. The San 3dro formation is up to 2,000 feet thick in this basin and consists predominantly f yellow, red, and blue silty clay, with lenticular sands and gravels. The San Pedro formation contains two members notable as aquifers* namely he Epworth gravels and the Fox Canyon aquifer. The Epworth gravels, near the op of the San Pedro formation, are located in a rather limited area lying about wo to three miles north and northwest of Moorpark. They consist of up to 200 eet of gravel, gravelly clay, and silt, grading westward and southward into silt rid clay. The Epworth gravels are probably remnants of an ancient alluvial fan, hich accounts for their limited extent. The gravels have been folded and par- ially eroded so that they now outcrop in the area shown on the geologic map [Plate B-1C) and they underlie a total area of about six square miles. The basal Fox Canyon member of the San Pedro formation has been named rom its excellent exposure in Fox Canyon, about a mile west of Bradley Road. It onsists of from 100 to 400 feet of sand and gravel containing some clay and silt .enses. The outcrop of the Fox Canyon member along the south slope of Oak Ridge s irregularly bedded as a result of facies changes and scour and fill, and varies onsiderably in total thickness. Fossils found in the member indicate deposition .nder shallow marine conditions. Sediments of the Fox Canyon member generally .re white or gray in color. These sediments can be easily differentiated on the >utcrop from the underlying Grimes Canyon sediments because of the distinct brown :oloring of the latter. In well logs it is usually difficult to dif ferentiat e ''ox and Grimes Canyon sediments. From a study of all available logs it is clear -hat the Fox Canyon aquifer extends under most of East Las Posas Basin. In gener- il, the Fox Canyon aquifer is thickest in the central portion of the basin where B-103 it consists principally of coarse sand. On Oak Ridge it is variable in thickness and consists of gravel and sand grading into fine sand near Happy Camp Canyon, where it pinches out entirely. On the Las Posas Hills it consist of sand and gra- vel, grading into sand near Moorpark. In East Las Posas Basin, most of the San Pedro formation other than the above mentioned aquifers consists of fine silt and clay with scattered lenses of gravel and sand, Since individual gravel lenses are quite local, and since yield of wells in this material is generally quite low, this portion is here called the semi-permeable portion of the San Pedro formation. These materials overlie the Fox Canyon aquifer, and confine the ground water under pressure in that aquifer. The Santa Barbara formation underlies the San Pedro formation and in this basin consists of up to 2,000 feet of clay, silt, sand, and gravel. At the west end of Oak Ridge it consists of clay and silt, but east of Bradley Road sand and gravel lenses become more common along the outcrop until in Happy Camp Canyon they predominate. The formation also thins to about 1,000 feet near Happy Camp Canyon. A coarse gravel member near the top of the Santa Barbara formation is exposed east and north of Bradley Road and is called the Grimes Canyon aquifer. This aquifer consists of coarse to fine brown gravel, sand, and lenses of clay anc silt. The rusty brown color of the Grimes Canyon is usually distinctive, but oc<- sionally is not evident in exposures or well logs. The aquifer varies in thickms from zero to about 1,000 feet in Happy Camp Canyon where it comprises nearly all the Santa Barbara formation. The Grimes Canyon aquifer underlies most of East L* Posas Basin. The Grimes Canyon aquifer is overlain by the Fox Canyon aquifer, and several outcrops reveal them to be in direct contact, although a clay member witln the Santa Barbara formation separates the two aquifers in other exposed areas. 'ie thickness of the aquifers indicated by some water and oil well logs suggests tha the Fox Canyon and Grimes Canyon aquifers are in direct contact under much, if n'> B-104 mist, of East Las Posas Basin. It is possible that some of the sediments of the Sata Barbara formation in Tapo Canyon are also the equivalent of the Grimes Can- in member. The detailed field work necessary to make such a discrimination was ip undertaken in this investigation. The Santa Barbara formation with exception o the Grimes Canyon aquifer previously described is for the most part composed Of materials of low permeability. The San Pedro formation, Santa Barbara formation, and the underlying Pco, Modelo, Vaqueros, and Sespe formations are all folded and faulted, only allu- vum being undisturbed. In general, East Las Posas Basin is a synclinal area, panging gently westward, and includes several minor en echelon synclines and anti- cines. Oak Ridge and the Las Posas Hills are major anticlinal uplifts. The fold- ig of the area has resulted in the Fox Canyon and Grimes Canyon aauifers being bfried quite deeply in the central portion of the basin and exposed around the finges. Structural features and relationships of various aquifers are shown on Gologic Section N-N' and P-P', Plate 12-C. Occurrence of Ground Water . Ground water occurs in the sands and gravels cj the alluvial deposits, in the Epworth gravels, and in the Fox Canyon and Grimes Inyon aquifers. Limited amounts of ground water occur in sands and gravel lenses i. the semi-permeable portion of the San Pedro formation which overlies the Fox C.nyon member. Limited supplies of water occur in the older semi- permeable forma- i.ons and may be of poor quality. Ground water in the alluvial deposits and in the Epworth gravels is es- untially unconfined, although water level behavior in some wells indicate locally >>nfined conditions. Ground water in the Fox Canyon and Grimes Canyon aquifers is onfined by the overlying silts and clays. Ground water is unconfined in these quifers, however, near their upturned edges which approximate the outcrop areas $ shown on Plate B-1C. B-105 Movement of Ground Water . Ground water in the alluvium near Moorpark generally moves westward toward Somis except during periods of low water level, when a pumping depression forms southwest of Moorpark. Ground water in the Epworth gravels appears to move in a southerly direction, indicating some movemen from the Epworth gravels into the semi-permeable portion of the San Pedro forma- tion. Ground water in the Pox Canyon aquifer moves in a southwesterly direc- tion from Happy Camp Canyon and the outcrop along the north side of East Las Pose Basin. Subsurface flow in the fall of 1951 as depicted by dashed ground water contours on Plate 16-C converges on the Somis area and moves into Pleasant Vallej Basin. Meager historic data suggests that in periods of high water levels grounc water in the Fox Canyon aquifer moves westward into West Las Posas Basin as well as into Pleasant Valley Basin. Water levels of fall 1951 indicate a ground watei mound in the piezometric surface of the Fox Canyon aquifer near the west boundary of East Las Posas Basin. Replenishment and Depletion of Ground Water . Ground water in East Las Posas Basin is replenished by percolation of direct precipitation, stream flow, and the un consumed portion of water applied for irrigation and other uses in out crop areas of aquifers, and possibly to some extent by subsurface inflow from older formations that surround the basin. Alluvium southwest of Moorpark along Arroyo Las Posas overlies the Fox Canyon aquifer where they are probably in hydr- logic continuity. In the vicinity of Somis and Moorpark, studies of water level and the chemical character of ground water have led to the conclusion that groun water moves from the alluvium into the Fox Canyon aquifer. East Las Posas Basin is depleted by pumped extractions from the Fox Ca- yon aquifer and by consumptive use of phreatophytes. Additional depletion is effected by subsurface outflow and export of water into West Las Posas Basin. B-106 yt Swings are reported to have flowed near Somis in Arroyo Las Posas in the early 190' s which would indicate that in periods of high water levels the basin was to soe extent depleted by effluent discharge. Subsurface Inflow and Outflow . Subsurface inflow into East Las Posas Berlin is limited to that coming from older rocks and about 100 acre-feet per r which enters from Simi Basin through alluvium. This latter increment of in- 'jw has been described under the paragraph on inflow and outflow to Simi Basin. 3usurface outflow into Pleasant Valley Basin through the Fox Canyon aquifer is iilicated by water level contours (Plates lU-C, 15>-C, and 16-C). This outflow has be;n estimated by the slope area method to be on the order of 3*000 acre-feet per H.r« As previously mentioned, subsurface outflow to West Las Posas Basin has pubably occurred in the past during periods of high ground water level. Ground Water Storage Capacity and Specific Yield . Changes in ground w?ier storage occurring within East Las Posas Basin during selected study periods wee estimated following the procedures described in Chapter B-VI and are discussed i Chapter II. Total storage capacity of aquifers in the basin could not be esti- m;;ed, but is probably very large. Depth to water in the outcrop area of the Fox Canyon and Grimes Canyon aaifers on Oak Ridge was approximately £00 or 600 feet in 19f>l and 19!?2, and tsrefore considerable available storage exists in these aquifers above the water tble. The average specific yield of the Fox Canyon and Grimes Canyon aquifers is bLieved to vary between 10 and 20 per cent. Estimated specific yield of the Evorth gravels is about six per cent; most of the remainder of the San Pedro for- mcion, three per cent, and the alluvium in the Moorpark area, eight per cent. B-107 Yield of Wells . Estimated average yield of wells in East Las Posas Basin is summarized below: Alluvium I4.OO gallons per minute Epworth Gravels 300 " " " Fox Canyon and Grimes Canyon Aquifers 600 " " " Serai-permeable portion of San Pedro formation 10 " » " Artificial Spreading of Water as a Means of Basin Replenishment . Water could be spread artificially on any portion of the outcrop area of the Fox Canyon or Grimes Canyon aquifers and reach the water table. The most desirable spreadin area for these aquifers is in Happy Camp Canyon about three miles north of Arroyo Simi. This locality has available surface area for construction of spreading grounds, high rates of percolation according to the Soil Conservation Service, an free access to the water table of the Grimes Canyon aquifer which is in hydrologi continuity with the Fox Canyon aquifer. In addition, the water table is about £C feet below the surface in this area so that adequate ground water storage is avai- able, A seismic survey of the spreading area by this Division indicates an ab- sence of clay lenses within 30 to 60 feet of the surface. Most other areas of outcrop have limited surface area available for construction of spreading works. Spreading into the Epworth gravels may be possible, but this would bene fit only the wells in these gravels. A large surface area is available for con- struction of spreading works near the corner of Broadway and Moorpark Roads, aboi two miles north of Moorpark, but spreading rates are probably low. Spreading into alluvium near Moorpark is feasible from percolation rate and surface area aspects. However, available storage of alluvium is probably smcl even when the alluvium is dewatered, and it might be filled by natural stream percolation of Arroyo Simi during wet periods. B-108 j fet Las Posas Basin West Las Posas Basin is located within the corresponding subunit and emprises about 11,1*50 acres, Elevation of the subunit ranges from 200 feet to_a nximum of 2,258 feet on South Mountain. Boundaries of West Las Posas Basin are lie outcrop of the Fox Canyon aquifer on the north, the surface drainage divide ci the east and south, and the limit of the Oxnard zone of Oxnard Plain and Guard Forebay Basins on the west. Geology . Aquifers of significance in West Las Posas Basin include the Iix Canyon and Grimes Canyon. The upper semi-permeable portion of the San Pedro J>rmation overlies the Fox Canyon aquifer and in turn is overlain by alluvium of Jjcent and upper Pleistocene age. The alluvium is not easily differentiated from "ie silts and clays of the underlying San Pedro formation, but it is probably up ') 200 or 300 feet thick. The alluvium consists of fine yellow silt and clay with attered lenticular sands and gravels and has been deposited in alluvial fans by mall streams draining Oak Ridge. The semi-permeable portion of the San Pedro ormation consists of over 1,000 feet of yellow and blue silty clay and clay, with mattered lenticular sands and gravels. The Fox Canyon aquifer consists of 200 to 300 feet of sand and gravel at ie base of the San Pedro formation. The Fox Canyon aquifer continues into East as Posas Basin, Oxnard Plain and Forebay Basins, and into the Camarillo Hills ,ad Pleasant Valley Basin. The Fox Canyon aquifer outcrops on the south slope of ak Ridge and in the east end of the Camarillo Hills. The Fox Canyon aquifer is underlain by the Santa Barbara formation which ontains the Grimes Canyon aquifer near its top. The Grimes Canyon aquifer does ot outcrop in the West Las Posas Basin but underlies it as shown by electric logs nd drillers logs. It consists of up to 300 feet of coarse gravel and sand. Well B-109 , logs indicate that a clay bed up to 600 feet thick lies between the Fox Canyon ai Grimes Canyon aquifers in the Camarillo Hills (see Section L-L 1 , Plate 12-B). A similar clay bed is found on the outcrop in East Las Posas Basin and it is likel 1 that these two clay beds are of a similar origin. Field inspection of the clay bed in East Las Posas Basin shows that an erosional unconformity at the base of tfr Fox Canyon aquifer has resulted in direct contact of the Fox Canyon and Grimes Canyon aquifers where the clay has been eroded. As in East Las Posas Basin, folding of the Fox Canyon has resulted in its being exposed on the edges of the basin and deeply buried in the middle. Th most prominent folds are the Camarillo Hills anticline and the Las Posas synclin Occurrence of Ground Water . The Fox Canyon and Grimes Canyon aquifers are the principal sources of ground water in West Las Posas Basin. Some water i derived from sand and gravel zones of limited extent contained within the semi- permeable portion of the San Pedro formation. Ground water in the Fox Canyon an Grimes Canyon aquifers is confined except where these aquifers outcrop on the southern slopes of Oak Ridge and where they have been folded in the Camarillo Hills (see Section L-L', Plate 12-B). Movement of Ground Water . Movement of ground water in 1951, as depict! by contours (Plate 16-C), was westerly in the Fox Canyon aquifer toward Oxnard Forebay Basin. Some ground water possibly moves southward across the Camarillo Hills, through the Springville fault zone, and into Pleasant Valley. Replenishment and Depletion of Ground Water . West Las Posas Basin is replenished by percolation of direct precipitation and stream flow on the outer* area of the Fox Canyon aquifer and possibly to some extent by subsurface inflow from East Las Posas Basin. The silty upper portion of the San Pedro formation alluvium may in addition be replenished by percolation of the unconsumed portio: of water applied for irrigation and other uses. West Las Posas Basin is deplet B-110 b; pumping from the Fox Canyon and other aquifers and by subsurface outflow. Subsurface Inflow and Outflow . Subsurface flow into West Las Posas 8 sin probably occurs from East Las Posas Basin during periods of high water lvel. Subsurface outflow occurs into Oxnard Plain and Pleasant Valley Basins trough the Fox Canyon aquifer. The outflow has been estimated by the slope area mthod to be on the order of 600 acre-feet per year into the Oxnard Plain Basin. Sbsurface outflow probably occurs across the Springville fault zone into Pleasant i Vlley Basin, but no data are available to estimate the amount. Since the ground vter divide in the piezometric surface of the Fox Canyon aquifer is located close t the surface divide, it is likely that subsurface outflow into East Las Posas Bsin through that aquifer is negligible. Ground Water Storage Capacity and Specific Yield . Change of ground water forage in West Las Posas Basin is discussed in Chapter II. Specific yield of the Ijix Canyon aquifer is estimated by inspection to be about 15 to 20 per cent. Spe- t.fic yield of the overlying San Pedro formation and the alluvium is estimated to h about three per cent. Yield of Wells . Yield of wells in the Fox Canyon and Grimes Canyon aqui- Jjrs averages about 600 gallons per minute. Wells in the semi-permeable portion t the San Pedro formation yield about ten gallons per minute. Artificial Spreading . Artificial spreading on the outcrop area of the 3x Canyon aquifer is physically possible, as in East Las Posas Basin, although ie rugged topography limits areas in which spreading works could be constructed. one.jo Basin Conejo Basin is located in the southern portion of the Calleguas-Conejo ydrologic Unit as shown on Plate 11. The basin varies in elevation from about B-lll 600 feet to 2,300 feet except on the floor of Cone jo Creek Canyon, the elevation of which is about 300 feet. Within the hydrologic unit most of the rocks includ- ing volcanics and consolidated sediments absorb and transmit water, but wells in these rocks generally yield small amounts of water. Since there are no areas which can be easily defined as ground water basins, the entire drainage area of about 28,930 acres is considered as the basin. Geology . Most of Cone jo Basin is an upland valley area which has drained eastward in the geologic past, possibly into Triunfo Creek. The ancestral drainage was subsequently captured by headward erosion of Cone jo Creek, so that the area now drains into Santa Rosa Basin. Geologic formations in Conejo Basin include alluvium, Modelo sandstone and shale, volcanic rocks, the Topanga formation, and limited exposures of the lower Llajas and Santa Susana-Martinez formations as well as some consolidated sediments of Cretaceous age. Alluvium of Recent and Pleistocene age occurs as valley fill in the Newbury Park and Thousand Oaks areas, on the floor of Conejo Creek Canyon, and as terrace deposits scattered throughout the basin. The alluvium is generally shallow, probably being only a few feet thich except in the valley fill areas where it attains a thickness of about 60 feet. The volcanic rocks, the Topanga formation, and the Modelo sandstones and shales are drilled by many wells in Conejo Basin, The limited outcrops of other formations are not generally drilled within the basin. All the aforementioned formations are des- cribed in Chapter B-III of this Appendix. All the formations with the exception of the alluvium are folded and faulted as shown on the geologic map (Plate B-1C). Occurrence of Ground Water . Ground water occurs in the alluvium, in the fractures and weathered portions of the volcanic rocks and Modelo shales, and in pervious zones of the Modelo sandstone and Topanga formations. The ground water B-112 srface conforms, in general, with the topography as shown on Plate 16-C and is essentially unconfined. Most wells in alluvial areas penetrate the alluvium com- pletely and obtain water from underlying formations as well as from alluvium. At ■ time of this investigation no water wells were lenown to have penetrated very duply into the older rocks. Scattered oil well logs indicate that such previous ziaes exist in the older rocks, but ouality of water in them is uncertain. Movement of Ground Water . Ground water from the periphery of the basin cnverges toward Cone jo Creek as indicated by ground water contours on Plate 16-C. Prennial springs which are supplied by subsurface flow from Conejo Basin exist i: the canyon of Conejo Creek. Replenishment and Depletion . Ground water is replenished by percolation I direct precipitation and stream flow as is evidenced by a close relationship Dbween water table and topography and fairly rapid recovery of water levels fol- lfling rains. Replenishment also occurs by percolation of the unconsumed portion o water applied for irrigation and other uses. Ground water is depleted by pnped extractions, by consumptive use of phreatophytes, by effluent discharge, ad, most likely, by subsurface outflow. Subsurface Inflow and Outflow . No subsurface inflow occurs into Caejo Basin. Subsurface outflow probably occurs into Santa Rosa Basin through te alluvial fill in Conejo Creek Canyon and through the volcanics. Subsurface ctflow may also occur into Pleasant Valley Basin, through the volcanics. Sub- srface outflow through volcanics appears to be possible because: 1. The volca- flcs dip toward Santa Rosa and Pleasant Valley Basins; 2. Water levels in Cnejo Basin are higher than in the other basins j 3» The volcanics are permeable. Aground water divide may exist in the same general location as the drainage B-113 divide but water level data are lacking to verify this possibility. If this were the case, subsurface flow into Pleasant Valley and Santa Rosa Basins through the volcanics would be negligible. Water level measurements in the Thousand Oaks area indicate that a ground water divide exists near the drainage divide so that subsurface flow in or out of the Malibu Hydrologic Unit is probably negligible. Storage Estimates . Change of storage does occur in Conejo Basin as evj denced by fluctuations of water levels and unconfined ground water conditions. Well log and historic water level data are lacking, however, and specific yield of the various formations in the basin is uncertain. For these reasons estimates of change in storage in Conejo Basin are not considered to be of sufficient accu- racy for use in the hydrologic balance. Yield of Wells . Because of the general low permeability of the forma- tions in Conejo Basin, average yield of wells is low and on the order of £0 gal- lons per minute. One exceptional well, however, yields 1,000 gallons per minute and several yield about 300 gallons per minute. Artificial Spreading . Artificial spreading in Conejo Basin does not appear to be feasible because of relatively shallow depths to water and the gen- eral low specific yield of the formations. Tierra Rejada Basin Tierra Rejada Basin is located between Simi, Conejo, Santa Rosa, and East Las Posas Basins as indicated on Plate 11. Surface elevation ranges from 6) feet in the valley floor to about 1,600 feet on the drainage divide. Nearly all Tierra Rejada Basin is underlain by water-bearing volcanic rocks. For this reasi the drainage divide is taken as the basin boundary. The basin includes an area of about U,390 acres. B-llH Geology . Although most of Tierra Rejada Basin is underlain by fractured vccanic rocks, a small portion is underlain by the Modelo, Topanga, and Sespe re mat ions. The volcanics consist of about 2,000 feet of basaltic flows, agglom- Bi.tes, rhyolitic tuffs, and interbedded conglomerates and clays. These materials ■i intruded by basaltic dikes and sills. All formations present are folded and faulted. In general the struc- tre of the basin is that of a westward plunging syncline. The volcanic rocks in ti3 southern and eastern parts of the basin dip from 10 to 30 degrees toward the fit irrigated portion of the basin. North of the irrigated area the attitude of tp volcanic rocks is nearly vertical. These rocks are terminated near the north bandary of the basin by the east-west trending Simi fault. Another fault trend- ig north-south displaces the volcanic rocks several hundred feet near the western sde of the basin. Occurrence of Ground Water . The volcanic rocks are generally highly iactured but appear to be most intensively fractured beneath the irrigated por- 1j.on of the basin, as wells in the volcanics have highest yields there. Ground v.ter occurs chiefly within these fractures, and is essentially unconfined. Movement of Ground Water . Ground water moves through the highly frac- ired volcanic rocks converging toward the westerly end of the basin. At the west ad subsurface flow out of the basin is impeded by the above mentioned north-south mlt. That this fault serves as a ground water barrier is evidenced by a pro- ounced drop in water level. In 1951 the ground water level east of this fault n Tierra Rejada Basin stood about 100 feet above the level observed in a well ituated near the fault on its westerly side. Movement of ground water is in- icated by ground water elevation contours on Plates 15-C and 16-C. Replenishment and Depletion of Ground Water . Tierra Rejada Basin is re- lenished by percolation of direct precipitation, stream flow, and the unconsumed B-115 portion of water applied for irrigation and other uses. The basin is depleted by pumped extraction, limited subsurface outflow into Santa Rosa Basin, and possibly effluent discharge and consumptive use of phreatophytes during periods of high water level. Subsurface Inflow and Outflow . No subsurface flow enters Tierra Rejad* Basin from Simi Basin. Water level measurements in the area of the drainage di- vide separating these basins indicates that a ground water divide exists which would prevent inflow from Simi Basin through the volcanics. If no ground water divide existed there, some inflow might be expected since water level elevations in the west portion of Tierra Rejada Basin are generally lower than in Simi Vail, As previously discussed, the north-south fault at the west end of Tier Rejada Basin limits subsurface outflow. A producing well situated a short dis- tance west of the fault suggests that this fault is only a partial barrier since the only feasible source of supply is subsurface flow across the fault. It is likely that subsurface flow northward across Simi fault into East Las Posas Basi is negligible. Ground Water Storage Capacity . As in Conejo Basin, poor geologic and hydrologic data resulted in uncertainties in change of storage estimates; so direct evaluation thereof could not be made.' ' Yield of Wells . Wells in Tierra Rejada Basin yield from 10 to 700 gal Ions per minute with an average yield in the principal pumping area of about 30 ( gallons per minute. Santa Rosa Basin Santa Rosa Basin, comprising about 3,490 acres, is located just east of Pleasant Valley Basin. It is bounded by the volcanics on the south, the limit the San Pedro formation on the north, Tierra Rejada Basin on the east, and the B-116 toographic narrows at the west end of the basin. Santa Rosa Basin ranges from 20 to over 400 feet in elevation with a maximum elevation of about 1,200 feet ibhe drainage divide. Geology . Principal water-bearing sediments in Santa Rosa Basin include I, Reent alluvium and the San Pedro formation . Formations underlying and adjacent tothe basin include the Santa Barbara, the Topanga and Sespe formations, and vol- aic rocks. Recent alluvium in Santa Rosa Basin consists of up to 200 feet of gravel, sad and clay. Fossil remains in outcrops of alluvium in the stream cut gullies irlcate that some of the clays in the west end of the basin have been deposited ir'a fresh water swamp or shallow lake. The San Pedro formation consists of up to 700 feet of gravel, sand, silt, ail clay. In the western end of the basin a sand and gravel member about 100 feet tllck can be traced in well logs at the base of the formation and is probably the euivalent of the Fox Canyon aquifer. This aquifer, however, cannot be traced in wll logs into the central and eastern portion of the basin. In general, the sands ai gravels of the San Pedro formation are extremely lenticular and with the above mntioned exception cannot be correlated between wells. In the west end of the bsin, the Santa Barbara formation is found below the San Pedro, but it contains vvter of poor quality. Only one or two wells are drilled into it here, so that its rture is poorly known, but it apparently consists of silt and clay with lenticular gavels and sands. The volcanics of Miocene age which underlie the alluvium and in Pedro formation on the south side of the basin are exposed in the hills to the !>uth where they dip ten to twenty- five degrees northward. The volcanics consist i'. over 2,000 feet of interbedded basaltic agglomerates and flows with scattered adesitic intrusions, all of which are fractured. The great thickness of volca- .cs on the south of the basin is represented in the Las Posas Hills by a basaltic B-117 sill about l£ feet thick. Relationships of the formations are shown on Geologic Sections N-N» and P-P« on Plate 12-C. All these formations except the alluvium have been folded and faulted. The structure of most significance is the east-west trending Santa Rosa syncline. shown on the geologic map (Plate B-1C), in which the San Pedro formation has beei folded. Field inspection of outcrops and well logs indicates that the north dipping flank of the syncline lies beneath the alluvium on the south side of San' Rosa Basin. The San Pedro formation and alluvium are underlain in part by volca- nics and other formations. The north flank of the folded San Pedro formation hai been cut off by the Simi-Santa Rosa fault system, exposing the semi-permeable Sespe and Topanga formations in the Las Posas Hills just north of the basin. Occurrence of Ground Water . Ground water occurs in pervious zones of the Recent alluvium and San Pedro formation and in the fractured volcanics. Wat of poor quality occurs in the Santa Barbara formation and possibly in the Sespe and Topanga formations. Ground water in Santa Rosa Basin is essentially uncon- fined, although the pervious lenses of the San Pedro formation are confined in some areas. Movement of Ground Water . Ground water in Santa Rosa Basin moves wes- terly and within the basin appears to move northerly from the volcanics and sou- therly in the San Pedro formation. Plate 16-C shows the southerly movement in t> fall of 19!?lj but the northern direction of movement at this time was not appre- ciable. When Cone jo Creek flows into Santa Rosa Basin, percolation occurs and a ground water mound is built up near the mouth of Cone jo Creek. Past measurement of a well on the extreme south side of the basin as well as the presence of springs in the volcanics indicate that some water probably moves directly from te volcanics into the alluvium. B-118 Replenishment and Depletion of Ground Water . Ground water in Santa Rsa Basin is replenished by percolation of direct precipitation, stream flow, and tie unconsumed portion of water applied for irrigation and other uses as well as ti subsurface inflow. The basin is depleted by pumped extractions, subsurface c.tflow, and by effluent discharge and consumptive use of phreatophytes during priods of high water Isvel, Subsurface Inflow and Outflow , Subsurface inflow to Santa Rosa Basin ccurs from Tierra Rejada and Cone jo Basins, Inflow from both these sources is cfficult to estimate by geologic methods because of the lack of wells and other eta. Subsurface outflow into Pleasant Valley through the San Pedro formation has ten estimated by the slope-area method to be about 200 acre-feet per year Ground Water Storage Capacity and Specific Yiel d, Estimates of change c' storage in alluvium and San Pedro formation are discussed in Chapter II, lighted average specific yield of the alluvium and San Pedro formation is es ti- nted to be five per cent. Yield of Wells , Water wells in Santa Rosa Basin yield up to 1,200 gal- lons per minute. Their yield averages about 600 gallons per minute, and specific upacities range from 10 to 30. The highest yielding well is in the volcanics, ad wells in the San Pedro formation generally yield slightly less than those in [jie alluvium. In general, these differences are controlled by permeability, but l some instances are dependent on the method of well construction. Artificial Spreading . Spreading in Santa Rosa Basin is feasible near le mouth of Conejo Creek, where most stream percolation has occurred. In the bher areas where surface conditions appear suitable for spreading, well log data re poor, and it is not known whether large quantities of water would percolate irectly to the water table. B-119 Miscellaneous Areas In and Near Ventura County The areas discussed below are those which contain ground water bodies c unknown extent and usefulness within and adjacent to Ventura County, but which ai outside the principal developed ground water areas. Malibu Hydrologic Unit i The Malibu Hydrologic Unit is located in the southeastern portion of the county and includes that portion of the Santa Monica Mountains draining soutl ward to the ocean. Principal geologic features are shown on Plate B-1C. Formations in this area include alluvium, Modelo sandstone and shale, volcanic rocks, the Topanga formation, and a small area of older sedimentary rocli Ground water is obtained from wells drilled into most of these formations. Prin- cipal water-bearing formations, however, are the alluvium and the volcanic rocks. Alluvium of Recent and Pleistocene age occurs as valley fill up to at least 100 feet thick in the upper drainage areas of Triunfo and Medea Creeks. Tl alluvial area which has most wells is Hidden Valley, located just west of Lake Sherwood. Water wells here penetrate alluvium and the underlying volcanic rocks, Nearly all the wells in Hidden Valley are used for domestic and limited irriga- tion purposes. Yield of wells is small in this area, probably averaging $0 gal- lons per minute. The low yield of the wells suggests that the alluvium and vole; nics are fairly impervious and have low specific yield and storage capacity. Th< direction of movement of ground water is eastward toward Lake Sherwood as shown on Plate l6-C. Downstream from Lake Sherwood a few irrigation wells obtain a good sup]J of ground water from the coarse alluvial gravels in the valley floor. In most o: the remaining alluvial areas shown on the geologic map few wells have been drills B-120 k, the alluvium is most likely thin and probably does not contain large quanti- zes of ground water. Numerous wells have been drilled into the volcanic rocks, the Topanga frmation, and the Modelo formation. Most of these wells yield small amounts of wter, but one well in the volcanics and one in the Topanga formation reportedly yeld 300 gallons per minute. Scattered well measurements and observations of Brings in the Malibu Hydrologic Unit indicate that the ground water surface con- inns in general with topography, as would be expected with formations of low j; rme ability. B ncon Subunit and Rincon Creek Drainage Area The Rincon subunit is located along the ocean between the Ventura River md the Santa Barbara-Ventura County line. Ground water bodies are extremely small i this subunit, being restricted to the alluvial filled valley bottoms, the beach ■posits, and the thin terrace deposits. Older formations probably contain water d' poor quality, as do the beach deposits during dry periods. Because of the lim- aed ground water bodies in the subunit only a few small wells are found there, n»st of the water being imported. The geology and occurrence of ground water in the Rincon Creek area has len discussed by Upson (1951). Since Rincon Creek recharges a ground water basin located mostly in Santa Barbara County, the area will not be further discussed here. C iyama River Drainage Area The principal development in the Cuyama River drainage area has occurred a Santa Barbara and San Luis Obispo Counties, This area has been described by bson and Worts (1951). The following discussion applies principally to the Ven- ira County portion of the drainage area which is utilized by only a few wells. B-121 Formations in the Ventura County portion of the Cuyama River drainage include alluvium, the Morales, Ouatal, Simmler, and older sedimentary formations as well as granitic rocks. All of these are described in Chapter B-III of this appendix. The principal water-bearing formation presently utilized is alluvium of Recent and Pleistocene age which appears to be 60 to 100 feet thick in the va. ley areas. The morales and portions of the Ouatal formations, although not pre- sently utilized by wells, appear from surface lithology to be potentially good sources of ground water. Pronounced lowering of water levels may occur in the area if the ground water is utilized, because of low rainfall and probable limitl recharge in the area of outcrop of the formations. Upper Portions of Piru Creek Drainage Areas in the upper portion of Piru Creek drainage where a few water we I are found include Lockwood Valley and Hungry and Peace Valleys. The latter two | valleys are located in the alluvial areas shown on Plate 10 near the northeast corner of Ventura County. In Lockwood Valley alluvium is very thin, and the few water wells in 1b area appear to be obtaining ground water from the continental sediments of Mioces age. One well in these sediments, however, had such a high boron content that i young apple orchard was destroyed by application of the water. The volume of ground water which is available for use is unknown, but is probably small. In Hungry and Peace Valleys a few water wells obtain a supply from the relatively thin alluvium and from sand and gravel of the underlying Ridge Basin group of sediments of Pliocene age. Two wells in the upper part of the Ridge Basin group reportedly yield large amounts of water for irrigation purposes. H is not known whether ground water storage and recharge is sufficient for potent:- future irrigation uses. B-122 BIBLIOGRAPHY /:elrod, D. I. ! The Piru Gorge Flora of Southern California. Carnegie Inst. Wash. Pub. 590, pp. 159-214. 1950. hiley, Thomas L. i Lateral Change of Fauna in the Lower Pleistocene. Bull. Amer. Assoc. Petrol. Geol., Vol. 46, pp. 489-502. 1935. Origin and Migration of Oil into Sespe Redbeds, California. Bull. Amer. Assoc. Petrol. Geol., Vol. 31, No. 11, pp. 1913-1935. 1937. I Late Pleistocene Coast Range Orogenesis in Southern California. Bull. Amer. Assoc. Petrol. Geol., Vol. 54, pp. 1549-1566. 1943. Underground Water Supply for Point Mugu Naval Base, Ventura County, California. Unpublished report for Point Mugu Naval Air Missile Test Center. Oct. 1948. !iiley, William C. South Mountain Oil Field. California Oil Fields, Vol. 29, No. 2. 1943. Shiells Canyon Area of Bardsdale Field. California Oil Fields, Vol. 31, No. 1. 1945. awalda, J. P., Gazin, C. L.,and Sutherland, J. C. Frazier Mountain, a Crystalline Overthrust Slab, West of Tejon Pass, Califor- nia. Pan-Amer. Geol., Vol. 54, No. 1, pp. 71-72. 1930. r alifornia Dept. of Public Works, Division of Water Resources Bulletin No. 45, South Coastal Basin Investigation - Geology and Ground Water Storage Capacity of Valley Fill. 1934. Bulletin No. 46, Ventura County Investigation. 1933. arlson, Stanley A. Stratigraphy of the Cuyama Valley Area, California. Paper given at Amer. Assoc. Petrol. Geol. meeting, Los Angeles, Oct. 31, 1952. art wright, L. D. Sedimentation of the Pico Formation in the Ventura Quadrangle, California. Bull. Amer. Assoc. Petrol. Geol., Vol. 12, No. 3, pp. 239-248. 1928. lements, Thomas Structure of the Southeastern Part of the Tejon Quadrangle, California. Bull. Amer. Assoc. Petrol, Geol., Vol. 21, No. 1, pp. 212-232. 1937. rowell, John C. Geology of Hungry Valley Area, Southern California. Bull. Amer. Assoc. Petrol. Geol., Vol. 34, pp. 1623-1646. 1950. Geology of the Lebec Quadrangle, California. Calif. Dept. Natural Resources, Div. of Mines, Special Report 24. Aug. 1952. B-123 Probable Large Displacement on the San Gabriel Fault, Southern California. Bull. Amer. Assoc. Petrol. Geol., Vol. 36, No. 10, pp. 2026-2035. Oct. 1952. Dehlinger, Peter Geology of the Southern Ridge Basin, Los Angeles County, California. Calif. Dept. Natural Resources, Div. of Mines, Special Report 26. 1952. Dibblee, T. W. Jr. Cuyama Valley and Vicinity. Amer. Assoc. Petrol. Geol. Guidebook, pp. 82-84. March 1952. Driver, H. L. Foraminif eral Section along Adams Canyon, Ventura County, California. Bull. Amer. Assoc. Petrol. Geol., Vol. 12, No. 7, pp. 753-756. 1928. Eaton, J. E. Divisions and Duration of the Pleistocene in Southern California. Bull. Amer Assoc. Petrol. Geol., Vol. 12, pp. 111-141. 1928. The By-Passing and Discontinuous Deposition of Sedimentary Materials. Bull. Amer. Assoc. Petrol. Geol., Vol. 13, No. 7, p. 750. 1929. Ridge Basin, California. Bull. Amer. Assoc. Petrol. Geol., Vol. 23, No. 4, pp. 517-558. 1939. i Eldridge, G. H. and Arnold, R. The Santa Clara Valley, Puente Hills and Los Anpeles Oil Districts, Southern California. U. S. Geol. Surv. Bull. 309. 1907. Emery, K. 0. and Rittenberg, S. C. Early Diagenesis of California Basin Sediments in Relation to Origin of Oil. Bull. Amer. Assoc. Petrol. Geol., Vol. 36, No. 5, pp. 735-806. May 1952. Emery, K. 0. and Shepard, F. P. Lithology of the Sea Floor Off Southern California. Bull. Amer. Assoc. Petri. Geol., Vol. 56, pp. 431-478. 1945. Handin, J. W. The Source, Transportation and Deposition of Beach Sediments in Southern Cal ornia. Beach Erosion Board, Office of the Chief of Engineers, Technical Mem randum No. 22. 1951. Hanna, G. D., and Hertlein, L. G. Characteristic Fossils of California, Calif. Dept. Natural Resources, Div. o Mines, Bull. 118, pp. 165-182, 1943. Herron, R. F. Thrust Faults of the Ventura Basin. Paper presented at meeting of the Amer. Assoc. Petrol. Geol., Los Angeles, Oct. 30, 1952. Hill, M. L. and Dibblee, T. W. Jr. San Andreas, Garlock, and Big Pine Faults, California. Bull. Geol. Soc. of America, Vol. 64, No. 4, PP. 443-458. 1953. B-124 . F>ots, H. W. Geolo© r of the Eastern Santa Monica Mountains, Los Angeles County, California. U. S. Geol. Surv. Prof. Paper 165-C 1931. Excursion in the Los Angeles Basin and the Santa Monica Mountains. 16th Int. Geol. Congr. Guidebook 15, pp. 43-48. 1932. '.man, D. L. Report on Beach Study in the Vicinity of Mugu Lagoon, California. Beach Ero- sion Board, Corps of Engineers, Technical Memorandum No. 14. Mar. 1950. Submarine Topography and Sedimentation in the Vicinity of Mugu Submarine Can- yon, California. Beach Erosion Board, Corps of Engineers, Technical Memorandum No. 19. July 1950. ttcobs, C. E. and Cooper, H. H. Jr. i A Generalized Graphical Method for Evaluating Formation Constants and Summar- izing Well Field History. Amer. Geophysical Union Trans., Vol. 27, No. 4, PP. 526-534- 1946. ahns, R. H. Stratigraphy of the Easternmost Ventura Basin, California. Carnegie Inst. Wash., Pub. 514, pp. 145-194. 1940. ■snkins, 0. P. Geologic Map of California. Calif. Dept. Natural Resources, Div. of Mines. 1938. Geomorphic Provinces of California. Calif. Dept. Natural Resources, Div. of Mines, Bull. 118, pp. 83-88. 1943. aplow, E. J. Oxnard Oil Field. California Oil Fields, Vol. 33, No. 2. 1947. ,ew, W. S. W. Geology and Oil Resources of a Part of Los Angeles and Ventura Counties, Calif- ornia. U. S. Geol. Surv. Bull. 753- 1924. limble , J . C . Underflow at Whittier Narrows, San Gabriel River Valley, Los Angeles County, California. Amer. Geophysical Union Trans., pp. 521-525. 1936. leinpell, R. M. Miocene Stratigraphy of California. Amer. Assoc. Petrol. Geol., 1938. errill, William R. Ojai to Ozena. Amer. Assoc. Petrol. Geol. Guidebook, pp. 77-81. Mar. 1952. atland, M. L. and Kuenen, Ph. H. Sedimentary History of the Ventura Basin, California, and the Action of Turbi- dity Currents. Soc. of Econ. Paleontologists and Mineralogists, Special Pub- lication No. 2, pp. 76-107. Nov. 1951. B-125 Natland, M. L. Pleistocene and Pliocene Stratigraphy of Southern California. Unpublished Ph. D. Thesis, Univ. Calif. Los Angeles. 1952. Poland, J. F., Garrett, A. A., and Mann, J. F. (U. S. Geological Survey) Progress Report on Water Supply for the Point Mugu Naval Base, Ventura County, California. Typewritten report for the Bureau of Yards and Docks, Dept. of the Navy. August 20, 1948. Putnam, William C. Geomorphology of the Ventura Region. Bull. Geol. Soc. Amer. , Vol. 53, pp. 691-754. 1942. Reed, R. D. Geology of California. Amer. Assoc. Petrol. Geol. 1933. Reed, R. D. and Hollister, J. S. Structural Evolution of Southern California. Bull. Amer. Assoc. Petrol. Geol Vol. 20, No. 12, pp. 1533-1704. 1936. Sheller, J. W. and Bien, M. N. Thrust Fault Zones in Ventura Basin, Los Angeles and Ventura Counties, Calif- ornia. Bull. Amer. Assoc. Petrol. Geol., Vol. 31, pp. 1505-1509. 1947. Soper, E. K. Geology of the Central Santa Monica Mountains, Los Angeles County, California Jour. Mines and Geol., Vol. 34, pp. 131-180. 1938. Stipp, T. F. Simi Oil Field. Calif. Dept. Natural Resources, Div. of Mines, Bull. 118, pp. 4L 7-423. 1943. Stock, Chester Oreodonts from the Sespe Deposits of South Mountain, Ventura County, Caliform, Carnegie Inst. Wash., Pub. 404, pp. 27-41. 1930. Eocene Land Mammals on the Pacific Coast. Proc. Nat. Acad. Sci., Vol. 18, No. 7, pp. 518-523. 1932. An Upper Oligocene Mammalian Fauna from Southern California. Proc. Nat. Acac Sci., Vol. 18, No. 8, pp. 550-554. 1932. Tolman, C. F. Ground V/ater. McGraw-Hill Book Co. 1937. Upson, J. E. Geology and Ground Water Resources of the South-Coast Basins of Santa Barbara County, California. U. S. Geol. Surv. Water Supply Paper 1108. 1951. Upson, J. E. and Worts, G. E. Jr. Ground Water in the Cuyama Valley, California. U. S. Geol. Surv. Water Supp Paper 1110-B. 1951. B-126 ilace, R. E. Structure of a Portion of the San Andreas Rift in Southern California. Bull. Geol. Soc. Amer., Vol. 60, pp. 781-806. 1949. Vfaerfall, L. N. A Contribution to the Palentology of the Fernando Group, Ventura County, Calif- ornia. Univ. Calif. Bull. Dept. Geol. Sci., Vol. 18, No. 3, pp. 71-92. 1929. iizel, L. K. Methods for Determining Permeability of Water-Bearing Materials. U. S. Geol. Surv. Water Supply Paper 887. 1942. B-127 PLATE B-1A PLATE B-IS SEE PLATE B-IC FOR GEOLOGIC LEGEND VENTURA COUNTY INVESTIGATION AREAL GEOLOGY 1953 PLATE B-IC PLATE B - 2 STRATIGRAPHIC COLUMNS - VENTURA COUNTY REGION SANTA MONICA MOUNTAINS CONEJO AND TIERRA REJAOA BASINS- MALIBU H OAK RIDGE-SOUTH MOUNTAIN SIMI HILLS-SANTA SUSANA MOUNTAINS COASTAL PLAIN , OXNARO FOREBAY, OXNARD PLAIN PLEASANT VALLEY BASINS VENTURA RIVER DRAINAGE AND SANTA PAULA BASIN SESPE-PIRU CREEK AREA FILLMORE-PIRU SUBUNITS NORTH OF THE SANTA CLARA RIVER CUYAMA RIVER DRAINAGE AREA EASTERN SANTA CLARA RIVER DRAINAGE AREA TERRACE DEPOSIT OXNARD PLAIN: Slrei ELSEWHERE^ Cloy, ! PLEISTOCENE e depotitr Sond ond gravel, O-lfto' -400 (hick, Oxnord I PEORO FORMATION Marine «y, iand and irav«l, 500-2000' thick Epworth gravel*, .ear top of formotlon, 0-300'. Fo» Conyon nember-»ond and grovel, I00'-300' thick SIMI BASIN Con) SAN PEORO FORMATION; Mar.ne and non-morlne cloy, land ond grovel, 600-4000' thick Fo« Conyon member-sond ond grovel, 100-300' thick In Oinord Ploln and Pleoiont Valley at SAN PEORO FORMATIO SAN PEDRO FORMATION I SANTA BAR8ARA FORMATION Mori ■ond and gravel, 1000- ZOOO'lhl Conyon member- eond ond grovel SANTA BARBARA FORMATION: SANTA BARBARA FORMATION: r FORMATION Marine 'ICO FORMATION: Brown and groy I elan* and eonglomerole, 0-900' I Unconformity - SANTA MARGARITA" FORMATION Siliceous IIDGE BASIN GROUP -Unconformity - Misting SAUGUS FORMATION: Continental cloy.iond and grovel, 2300' thic •ICO FORMATION. Shoi ',5500'lhlc MODELO SHALE: Brown I Shale, 200 - 1500 I MODELO SANOSTONE AND SHALE: 2000' I Unconformity MINT CANYON FORMATION: Continental sands and conglomerat e. 4000' th.ek. Shole, 400 - 1600 II Sondstone. 200'- 2000' t VAQUEROS FORMATION: Shole oi Unconformity - SESPE FORMATION: I SIMMLER FORMATION: Cor :SPE FORMATION: Not I SESPE FORMATION: Cor COLDWATER SANDSTONE I COZY OELL SHALE: DSTCNE Marine, 2400' MATILIJA SANDSTONE: Marine, 4000' t Marine ehale ond sandstone, nol eipoied. ALE AND SANDSTONE: Marine, 5000 Unconformity -Fault or Unconformity - CRETACEOUS PRE- CRETACEOUS mqlamerate, 5000' ■ Base not exposed - I generolly confc column heodlngi BASEMENT COMPLEX I PLATE B-3 ^q 200 400 HUENEME OXNARD PLAIN___J__^25M^— ! CANYON^- - — -^'. ••■'■'.•..■.■.'■ •*;•'• f . " ''•'•'" ■■'■■■.' /: ■':■ :. ■•■ • OXNAftP_J»QJJJl^S 1 - ■ ■ 200 ,400 DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION SUBMARINE TOPOGRAPHY AND DIAGRAMATIC SECTIONS SCALE OF MILES 2 4 6 8 10 Line of equal depth to ocean floor APPENDIX C ESTIMATES OF COST TABLE OF CONTENTS ESTIMATES OF COST Estimated Cost of Casitas Dam and Reservoir With Storage Capacity of 92,000 Acre-feet C-l Estimated Cost of Casitas Dam and Reservoir With Storage Capacity of 105,000 Acre-feet C-3 Estimated Cost of Casitas Dam and Reservoir With Storage Capacity of 130,000 Acre-feet C-5 Estimated Cost of Casitas Dam and Reservoir With Storage Capacity of 156,000 Acre-feet C-7 Estimated Cost of Ventura River Diversion to Casitas Reservoir With Conduit of 100 Second-foot Capacity and Diversion at . • Middle Site C-9 Estimated Cost of Ventura River Diversion to Casitas Reservoir With Conduit of 150 Second-foot Capacity and Diversion at Middle Site C-ll Estimated Cost of Ventura River Diversion to Casitas Reservoir With Conduit of 200 Second-foot Capacity and Diversion at Middle Site C-13 Estimated Cost of Ferndale Dam and Reservoir With Storage Capacity of 12,000 Acre-feet C-l!? Estimated Cost of Ferndale Dam and Reservoir With Storage Capacity of 2U,000 Acre-feet C-17 Estimated Cost of Ferndale Dam and Reservoir With Storage Capacity of 3h,000 Acre-feet C-19 Estimated Cost of Cold Spring Dam and Reservoir With Storage Capacity of 35,000 Acre-feet C-21 Estimated Cost of Cold Spring Dam and Reservoir With Storage Capacity of 1*3,000 Acre-feet C-23 Estimated Cost of Cold Spring Dam and Reservoir With Storage Capacity of 77,000 Acre-feet C-2$ Estimated Cost of Cold Spring Dam and Reservoir With Storage Capacity of 100,000 Acre-feet C-27 Estimated Cost of Topatopa Dam and Reservoir With Storage Capacity of £0,000 Acre-feet • C-29 Estimated Cost of Topatopa Dam and Reservoir With Storage Capacity of 75*000 Acre-feet C-30 C-i TABLE OF CONTENTS ESTIMATES OF COST (Continued) Page stimated Cost of Topatopa Dam and Reservoir With Storage Capacity of 100,000 Acre-feet C-31 stimated Cost of Hammel Dam and Reservoir With Storage ; Capacity of 25,000 Acre-feet C-32 stimated Cost of Hammel Dam and Reservoir With Storage Capacity of 50,000 Acre-feet C-34 stimated Cost of Upper Blue Point Dam and Reservoir With Storage Capacity of 50,000 Acre-feet . C-36 stimated Cost of Blue Point Dam and Reservoir With Storage Capacity of 50,000 Acre-feet C-3S stimated Cost of Devil Canyon Dam and Reservoir With Storage Capacity of 100,000 Acre-feet C-40 stimated Cost of Devil Canyon Dam and Reservoir With Storage Capacity of 150,000 Acre-feet C-42 Istimated Cost of Santa Felicia Dam and Reservoir With Storage Capacity of 50,000 Acre-feet C-44 'stimated Cost of Santa Felicia Dam and Reservoir With Storage ! Capacity of 75,000 Acre-feet • . C-46 stimated Cost of Santa Felicia Dam and Reservoir With Storage Capacity of 100,000 Acre-feet C-48 stimated Cost of Distribution System From Casitas Reservoir C-50 stimated Cost of Casitas-Oxnard Plain Diversion C-55 stimated Cost of Santa Clara River Conduit - Devil Canyon Dam to Sespe Creek C-56 stimated Cost of Santa Clara River Conduit - Santa Felicia Dam to Sespe Creek C-57 stimated Cost of Santa Clara River Conduit - Sespe Creek to Oxnard Reservoir ....... C-58 stimated Cost of Santa Clara River Conduit - Sespe Feeder C-59 stimated Cost of Oxnard Plain-Pleasant Valley Distribution System C-60 stimated Cost of Oxnard-Port Hueneme Conveyance and Pumping System C-61 C-ii TABLE OF CONTENTS ESTIMATES OF COST (Continued) Estimated Cost of Piru-Las Posas Diversion Conduit . . Estimated Cost of Spreading Works in East Las Posas and Simi Basins Estimated Cost of Fillmore Well Field Estimated Cost of Ventura County Aqueduct to Connect With Facilities of Metropolitan Water District of Southern California - 25 Second-feet • Estimated Cost of Ventura County Aqueduct to Connect With Facilities of Metropolitan Water District of Southern California - 50 Second-feet Estimated Cost of Ventura County Aqueduct to Connect With Facilities of Metropolitan Water District of Southern California - 75 Second-feet Estimated Cost of Ventura County Aqueduct to Connect With Facilities of Metropolitan Water District of Southern California - 100 Second-feet Estimated Cost of Ventura County Aqueduct to Connect With Facilities of Metropolitan Water District of Southern California - 150 Second-feet •• Estimated Cost of Oak Canyon Lateral •••• Estimated Cost of Oak Canyon Dam and Reservoir With Storage Capacity of 7,500 Acre-feet Estimated Cost of Conejo Dam and Reservoir With Storage Capacity of 20,000 Acre-feet . Estimated Cost of Distribution System for Colorado River Water in Calleguas-Conejo Hydrologic Unit Estimated Cost of Conduit to Deliver Colorado River Water From Conejo Reservoir to Oxnard Regulating Reservoir and the City of Ventura C-iii ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 92,000 ACRE-FEET (Based on prices prevailing in spring »f 1953) novation of crest of dam: 523 feet, l.S.G.S. datum Ovation of crest of spillway: 503 feet rfc.ght of dam to spillway crest, ibove stream bed: 178 feet Capacity of reservoir to crest of spillway: 92,000 acre-feet Capacity of spillway with 10#6-&ot freeboard: 17,000 second-feet Item Quantity Unit price Cost COITAL COSTS ft! diversion of stream and de- watering of foundati#n Sxcavation, stripping Stream bed, common rock Abutments, random Right abutment, slide area Sxcavation, from borrow pits Smbankment, compacted Gravel fill, pervious drain Rock riprap Drilling grout holes Pressure grouting Slope stabilization, planting Sillway Excavation Channel Cutoff Concrete Weir and bucket Walls Floor Cutoff Reinforcing steel Ctlet Works Excavation Stripping for tower Rock, tower foundation Rock, conduit trench Concrete Tower Pipe encasement Reinforcing steel Pipe, reinf. cone, 42- inch dia. lump sum $ 10,000 780,300 cu.yd. 41,000 cu.yd. 296,300 cu.yd. 50,000 cu.yd. 4,319,400 cu.yd. 4,715,400 cu.yd. 54,400 cu.yd. 55,300 cu.yd. 8,750 lin.ft. 4,400 cu.ft. 0.41 1.10 0.88 0.82 0.44 0.24 4.60 4.00 3.00 4.00 17.2 acres 1,000.00 2,000 cu.yd. 1.50 160 cu.yd. 6.00 1,200 cu.yd. 6.00 465 cu.yd. 80.00 640 cu.yd. 40.00 110,000 lbs. 0.15 1,000 lin.ft. 21.00 C-l 319,900 45,100 260,700 41,000 1,900,500 1,131,700 250,200 221,200 26,300 17, 600 82,600 cu.yd. 2.75 227,200 690 cu.yd. 6.00 4,100 625 cu.yd. 35.00 21,900 520 cu.yd. 40.00 20,800 1,400 cu.yd. 30.00 42.000 690 cu.yd. 35.00 24,200 323,300 lbs. 0.15 48. 500 17,200 &, 241,400 3,000 1,000 7,200 37,200 25,600 16, 500 21,000 388,700 ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 92,000 ACRE-FEET (continued) Item Quantity Unit price Cost CAPITAL COSTS Outlet Works (continued) Gate valves, 30- in, dia. Gate valves, 24-in. dia. Floor stands and stems Reducing thimbles, cast iron Miscellaneous metal work Control house Reservoir Land and improvements Highway relocation Relocation of utilities Clearing reservoir land Subtotal Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL 3 each 6 each $3,000.00 2,000,00 $ 9,000 12,000 lump sum 6,000 15,000 lbs. lump sum 0,40 lump sum 2,500 6,000 2.500 $149,500 800 acres 4 lump sum lump sum lump sum 150.00 1,500,000 415,000 60,500 120.000 2,095,? $6,875,K $ 687,5) 1,031,3(' $8,937,7<> ANNUAL COSTS Interest, k% Amortization, 40-year sinking fund at U% Operation and maintenance TOTAL 357,5(' 94,00 15JD» _ $ 466,5<> C-2 ESTIMATED COST OF CASITAS DM AND RESERVOIR WITH STORAGE CAPACITY OF 105,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 533 feet U.S.G.S. Datum Elevation of crest of spillway: 513 feet Height of dam to spillway crest, above stream bed: 188 feet Capacity of reservoir to crest of spillway: 105,000 acre-feet Capacity of spillway with 9-foot freeboard: 17,000 second-feet « t Unit : Item : Quantity : price : Cost CAPITAL COSTS Dam Diversion of stream and de\\ratering of foundation lump sum $ 10,000 Excavation, stripping Stream bed, common 830,400 cu.yd. $ 0.41 340,500 rock 43,800 cu.yd. 1.10 48,200 Abutments, random 310,400 cu.yd. 0.88 273,200 Right abutment, slide area 50,000 cu.yd. 0.82 41,000 Excavation, from borrow pits 5,013,800 cu.yd. 0.44 2,206,100 Embankment, compacted 5,461,800 cu.yd. 0.24 1,310,800 Gravel fill, pervious drain 62,700 cu.yd. 4.60 288,400 Rock riprap 68,000 cu.yd. 4.00 272,000 Drilling grout holes 10,330 lin.ft. 3.00 31,000 Pressure grouting 5,170 cu.ft. 4.00 20,700 Slope stabilization, planting 17.3 acres 1,000.00 17,300 &4. 859. 200 Spillway Excavation Channel Cutoff Concrete Weir and bucket Walla Floor Cutoff Reinforcing steel Outlet Works Excavation Stripping for tower Rock, tower foundation Rock, conduit trench Concrete Tower Pipe encasement Reinforcing steel 55,300 cu.yd. 2.75 152,100 640 cu.yd. 6.00 3,800 590 cu.yd. 35.00 20,700 630 cu.yd. 40.00 25,200 1,530 cu.yd. 30.00 45,900 540 cu.yd. 35.00 18,900 330,000 lbs. 0.15 49.500 2,000 cu.yd. 1.50 3,000 390 cu.yd. 6.00 2,300 1,320 cu.yd. 6.00 7,900 520 cu.yd. 80.00 41,600 700 cu.yd. 40.00 28,000 121,900 lbs. 0.15 18,300 316,100 C-3 ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 105,000 ACRE-FEET (Continued) Item : Quantity : Unit : price : Cost CAPITAL COSTS Outlet Works (Continued) Pipe, reinf. cone. 42-in. dia. Gate valves, 30-in. dia. Gate valves, 24-in. dia. Floor stands and stems Reducing thimbles, cast iron Miscellaneous metal work Control house 1,100 4 5 20,000 lin.ft. each each lbs. $ 21.00 3,000.00 2,000.00 lump sum lump sum 0.40 lump sum $ 23,100 12,000 10,000 6,500 3,000 8,000 2.900 $ 166,2C Reservoir Land and improvements Highway relocation Relocation of utilities Clearing reservoir land 850 acres lump sum lump sum lump sum 150.00 1,500,000 415,000 60,500 127,500 2.103.0C Subtotal &7,444, 5C Administration and engineering. Contingencies, 15$ Interest during construction , 10$ & 744, 4C 1,116,7C 372, 2C TOTAL #9,677,8C ANNUAL COSTS Interest, k% Amortization, 40-year sinking fund at U% Operation and maintenance 387, K 101, 8C 18. PC TOTAL $ 506, 9C C-4 ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 130,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: Capacity of reservoir to crest of 547 feet, U.S.G.S. datum spillway: 130,000 acre-feet Elevation of crest of spillway: Capacity of spillway with 9-foot 527 feet freeboard: 17,000 second feet Height of dam to spillway crest, above stream bed: 202 feet • • : Unit : Item : Quantity : price Cost CAPITAL COSTS Dam Diversion of stream and dewatering of foundation lump sum $ 10,000 Excavation, stripping Stream bed, common 986,800 cu.yd. $ 0.41 404,600 rock 55,800 cu.yd. 1.10 61,400 Abutments, random 476,300 cu.yd. 0.88 419,100 Right abutment, slide area 50,000 cu.yd. 0.82 41,000 Excavation, from borrow pits 6,390,600 cu.yd. 0.44 2,811,900 Embankment, compacted 6,934,100 cu.yd. 0.24 1,664,200 Gravel fill, pervious drain 70,640 cu.yd. 4.60 324,900 Rock riprap 120,400 cu.yd. 4.00 481,600 Drilling grout holes 15,500 lin.ft. 3.00 46,500 Pressure grouting 7,740 cu . f t . 4.00 31,000 Slope stabilization, planting 19.7 acres 1,000.00 19.700 $6,315,900 Spillway Excavation Channel 44,950 cu.yd. 2.75 123,600 Cutoff 610 cu.yd. 6.00 3,700 Concrete Weir and bucket 590 cu.yd. 35.00 20,700 Walls 610 cu.yd. 40.00 24,400 Floor 1,170 cu.yd. 30.00 35,100 Cutoff 510 cu.yd. 35.00 17,900 Reinforcing steel 287,800 lbs. 0.15 43,200 268,600 Outlet Works Excavation Stripping for tower 2,000 cu.yd. 1.50 3,000 Rock, tower foundation 390 cu.yd. 6.00 2,300 Rock, conduit trench 2,090 cu.yd. 6.00 12,500 Concrete Tower 570 cu.yd. 80.00 45,600 Pipe encasement 740 cu.yd. 40.00 29,600 Reinforcing steel 129,000 lbs. 0.15 19,400 Pipe, reinf. cone. 48- in. dia. 1,150 lin.ft. 24.00 27,600 C-5 ESTIMATED COST OF CaSITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 130,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Outlet Works (Continued) Gate valves, 30-in. dia. Gat - * valves, 24-in. dia. Floor stands and stems Reducing thimbles, cast iron Miscellaneous metal work Control house Reservoir Land and improvements Highway relocation Relocation of utilities Clearing reservoir land Subtotal Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL 5 each 4 each $3,000.00 $ 2,000.00 15,000 8,000 lump sum 6,500 20,000 lbs. lump sum 0.40 3,000 8,000 lump sum 2.500 900 acres lump sum 1 lump sum lump sum 150.00 ,500,000 415,000 60, 500 135,000 $ 183, 0C 2 t 110,ff» $ 8,878,00 $ 887,80 1,331,70 665.90 ■ $11,763,40 ANNUAL COSTS Interest, 1$ Amortization, 40-year sinking fund at Operation and maintenance TOTAL 9 470,50 123,80 21.00 615,30 C-6 ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 156,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 560 feet, U.S.G.S. datum Elevation of crest of spillway: 540.5 feet Height of dam to spillway crest, above stream bed: 215 feet Capacity of reservoir to crest of spillway: 156,000 acre- feet. Capacity of spillway with 8.5- foot freeboard: 17,000 second-feet Item Quantity Unit price C03t CAPITAL COSTS Dam Diversion of stream and dewatering of foundati Excavation, stripping Stream bed, common rock Abutments, random Right abutment, slide Excavation, from borrow pits Embankment , compa ct ed Gravel fill, pervious drain Rock riprap Drilling grout holes Pressure grouting Slope stabilization, planti ng Spillway Excavation Channel Cutoff Concrete Weir and bucket Walls Floor Cutoff Reinforcing steel Outlet Works Excavation Stripping for tower Rock, tower foundation Rock, conduit trench on lump sum § 10,000 1,132,700 59,600 1,404,400 area 50,000 cu.yd. 5 cu.yd. cu.yd. cu.yd. I 0.41 1.10 0.88 0.82 464,400 65,600 1,235,900 41,000 11,731,900 12,441,800 cu.yd. cu.yd. 0.44 0.24 5,162,000 2,986,000 77,600 270,800 19,850 9,950 cu.yd. cu.yd. lin.ft. cu.ft. 4.60 4.00 3.00 4.00 357,000 1,083,200 59,600 39,800 31.9 acres 1,000.00 31,900 158,400 720 cu.yd. cu.yd. 2.75 6.00 435,600 4,300 395 840 2,070 720 403,000 cu.yd. cu.yd. cu.yd. cu.yd. lbs. 35.00 40.00 30.00 35.00 0.15 13,800 33,600 62,100 25,200 60,500 1,370 550 3,160 cu.yd. cu.yd. cu.yd. 1.50 6.00 6.00 2,100 3,300 19,000 635,100 C-7 ESTIMATED COST OF CASITAS DAM AND RESERVOIR WITH STORAGE CAPACITY OF 156,000 ACRE-FEET (Continued) • : Unit : Item : Quantity : price : Cost CAPITAL COSTS Outlet Works (Continued) Concrete Tower 693 cu.yd. % 80.00 % 55,400 Pipe encasement 1,110 cu.yd. 40.00 44,400 Reinforcing steel 182,500 lbs. 0.15 27,400 Pipe, reinf. con. 48- in. dia. 1,740 lin.ft . 24.00 41,800 Gate valves, 30- in. dia. 6 each 3,000.00 18,000 Gate valves, 36-in. dia. 3 each 5,000.00 15,000 Floor stands and stems lump sum 6,500 Reducing thimbles, cast iron lump sum 3,000 Miscellaneous metal work 25,000 lbs. 0.40 10,000 Control house lump sum 2.500 % 248.4C Reservoir Land and improvements lump sum 1,500,000 Highway relocation lump sum 415,000 Relocation of utilities lump sum 60,500 Clearing reservoir land 1,000 acres 150.00 150.000 2.125,50 Subtotal $14,545,40 Administration and engineering, 10$ % 1,454,50 Contingencies, 15$ 2,181,80 Interest during construction 1.^54.50 TOTAL $19,636,20 ANNUAL COSTS Interest, k% % 785,50 Amortization, 40-year sinking fund at k% 206,60 Operation and maintenance 25,00 TOTAL % 1,017,10 --' C-8 ESTIMATED COST OF VENTURA RIVER DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 100 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Based on prices prevailing in spring of 1953) Elevation at crest of weir: 910 feet, U.S.G.S. datum Height of weir above stream bed: 10 feet Total length of pipe line: 17,600 feet Total length of canal znd flume: 1U,730 feet Item Quantity Unit Price Cost CAPITAL COSTS Diversion Works Excavation Stripping Concrete 200 cu.yd. 870 cu.yd. $ U.QO $ 3.00 800 2,600 Weir and cutoff Walls Reinforcing steel Trash rack steel Outlet gates 750 cu.yd. 20 cu.yd. 2,500 lbs. 1,000 lbs. 35.00 50.00 0el5 0.20 lump sum 26,300 1,000 400 200 2,200 $33,500 Pipe Line Pips , reinforced concrete, U2-inch, installed including earthwork Air valves, blowoffs, and structures Sand trap Canal and Flume Excavation Compacted fill Shotcrete lining Flume, semicircular, metal, 6,k foot diameter, including structures Flume, semicircular, metal, 7.0 foot diameter including structures Special structure Farm road bridges Rights of Way Canal Pipe line Subtotal 17,600 lin.ft. 23.31 110,300 lump sum lump sum 26,000 9,800 14*6,100 52,690 cu.yd. 6,870 cu.yd. 21,600 sq.yd. 0.15 0.31 3.50 23,700 2,100 75,600 600 lin.ft. 21.80 13,100 30 lin.ft. 18.20 500 k each lump sum 2,200.00 17,000 8,800 1 hO, 800 20 acres 1,000.00 20,000 21 acres 150.00 3,200 23,200 $6U3,600 C-9 ESTIMATED COST OF VENTURA RIVER DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 100 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Continued) Unit price Item Quantity Cost CAPITAL COSTS Administration and engineering, 10$ Contingencies, 1$% Interest during construction TOTAL $ 6U,l*oo 96,500 32,200 ^836,700 ANNUAL COSTS Interest, h% Amortization, IiO-year sinking fund at k% Operation and maintenance TOTAL 4 33,500 8,800 U,000 $ 1*6,300 C-10 ESTIMATED COST OF VENTURA RIVER DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 150 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Based on prices prevailing in spring of 1953) lev at ion at crest of weir: 910 feet, U.S.G.S. datum [eight of weir above stream bed: 10 feet Total length of pipe line: 17,600 feet Total length of canal and flume: 1U,730 feet Item APITAL COSTS Quantity : Unit : : price : Cost iversion Works Excavation Stripping Concrete Weir and cutoff Walls Reinforcing steel Trash rack steel Outlet gates ipe Line Pipe, reinforced concrete, U8-inch diameter, installed Air valves, blowoffs, and s true tures Sand trap anal and Flume Excavation Compacted fill Shotcrete lining Flume, semicircular, metal, 7.6 foot diameter, including structures Flume, semicircular, metal, 8.3 foot diameter, including structures Special structures Farm road bridges ights of Way Canal Pipe line Subtotal 200 cu.yd. 870 cu.yd. $ I4.OO $ 3.00 800 2,600 750 co. yd. 20 cu.yd. 2,500 lbs. 1,000 lbs. 35.00 50.00 0.15 0.20 26,300 1,000 Uoo 200 lump sum 2,200 $33,500 17,600 lin.ft. 26.62 U68,500 lump sum lump sum 28,100 9,800 $06,1*00 71,560 cu.yd. 11,610 cu.yd. 29,328 sq.yd. 0.31 3.50 32,200 3,600 102,600 600 lin.ft. 29.^0 17,600 30 lin.ft. 25.80 800 h each lump sum 2,200.00 17,000 8,800 182,600 3U acres 21 acres 1,000.00 150.00 3h, 000 3,200 37,200 $759,700 c-11 ESTIMATED COST OF VENTURA RIVER DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 150 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Continued) Item Quantity Unit price Cost CAPITAL COSTS Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL > 76,000 113,900 38,000 $ 987,600 ANNUAL COSTS Interest, k% Amortization, iiO-year sinking fund at k% Operation and maintenance 39,500 10,1*00 U,ooo TOTAL $ 53,900 ::~ C-12 ESTIMATED COST OF VENTURA RIVER DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 200 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Based on prices prevailing in spring of 1953) levation of crest oj weir: Total length of pipe line: 17,600 910 feet, U.S.G.S. datum feet eight of -weir above stream bed: Total length of canal and flume: 10 feet 1U,730 feet • « : Unit : Item : Quantity : price : Cost IPITAL COSTS Aversion Works . Excavation 200 cu.yd. $ U.00 $ 800 Stripping 870 cu.yd. 3.00 2,600 Concrete Weir and cutoff Walls 750 cu.yd. 35.00 26,300 20 cu.yd. 50.00 1,000 Reinforcing steel 2,500 lbs. 0.15 Uoo Trash rack steel 1,000 lbs. 0.20 200 Outlet gates lump sum 2,200 $ 33,500 i.Lpe Line I Pipe, reinforced concrete 5U-inch dia., installed : Air valves, blowoffs, and structures I Sand trap :Unal and Flume I Excavation Compacted fill • Shotcrete lining I Flume, semicircular, metal, 8.3~foot dia., including structures I Flume, semicircular, metal, 8.9-foot dia., including structures ; Special structures Farm road bridges 17,600 lin.ft. 30.97 5U5,100 lump sum lump sum 30,000 12,300 76,700 cu.yd. 11,610 cu.yd. 31,580 sq.yd. o.ii5 0.31 3.50 3U,500 3,600 110,500 600 lin.ft. 3U.60 20,800 30 lin.ft. 26.60 800 h each lump sum 2,200.00 18,100 8,800 587,1*00 197,100 ght of 17ay Canal Pipe line Subtotal 3k acres 1,000.00 21 acres 150.00 3li,000 3,200 37,200 855,200 C-13 ESTIMATED COST OF VENTURA RIVLR DIVERSION TO CASITAS RESERVOIR WITH CONDUIT OF 200 SECOND-FOOT CAPACITY AND DIVERSION AT THE MIDDLE SITE (Continued) : : Unit : Item ; Quantity : price : Cost CAPITAL COSTS Administration and engineering, 10$ £> 85, £00 Contingencies, \% 128,300 Interest during construction 1;2,800 TOTAL &, 111, 800 ANNUAL COSTS Interest, h% $ UU,!>00 Amortization, hD-year sinking fund at h% 11,700 Operation and maintenance 1|,000 TOTAL $ 60,200 C-lli ESTIMATED COST OF FERNDALE DAM AND RESERVOIR WITH STORAGE CAPACITY OF 12,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,100 feet, U.S.G.S. datum Elevation of crest of spillway: 1,075 feet Height of dam to spillway crest, above stream bed: 165 feet Capacity of reservoir to crest of spillway: 12,000 acre-feet Capacity of spillway with 5-foot freeboard: 37,000 second-feet Item Quality Unit price Cost CAPITAL COSTS Dam Exploration Diversion of stream and dewatering of foundation Stripping tops oil Foundation excavation Abutment Channel Embankment Impervious Pervious Rock riprap Drilling grout holes Pressure grouting Spillway Excavation Concrete Weir and cutoff Floor Walls Reinforcing steel Outlet Works Excavation Inlet structure Conduit trench Concrete Inlet structure Conduit encasement Reinforcing steel Miscellaneous metal work Steel pipe 42-inch dla. High pressure slide gate Needle valve, 36-inch dia. Control house, etc. lump sum $ 30,000 lump sum 10,000 26,600 cu.yd. $ 0.60 16,000 208,500 cu.yd. 1.10 229,400 20,700 cu.yd. 0.60 12,400 902,900 cu.yd. 0.70 632,000 1,408,500 cu.yd. 0.45 633,800 38,000 cu.yd. 4.00 152,000 5,880 lin.ft. 3.00 17,600 3,920 cu.ft. 4.00 15,700 328,800 cu.yd. 2.00 657,600 1,440 cu.yd. 35.00 50,400 1,340 cu.yd. 30.00 40,200 840 cu.yd. 40.00 33,600 267,800 lbs. 0.15 40,200 300 cu.yd. 5.00 1,500 7,920 cu.yd. 6.00 47,500 220 cu.yd. 60.00 13,200 3,590 cu.yd. 40.00 143,600 183,900 lbs. 0.15 27,600 32,400 lbs. 0.40 13,000 198,000 lbs. 0.28 55,500 lump sum 25,000 lump sum 12,000 lump sum 9,100 -,748,900 822,000 348,000 C-15 ESTIMATED COST OF FERNDAIE DM AND RESERVOIR WITH STORAGE CAPACITY OF 12,000 ACRE-FEET (Continued) : : Unit : Item : Quantity : price ; Cost CAPITAL COSTS Reservoir Land acquisition lump sum $ 25#,800 Improvements lump sum 576,700 State road relocation lump sum 420,000 Clearing 270 acres $ 150.00 40,500 $1.296.00C Subtotal $4,214,90C Administration and engineering, 10$ $ 421,50( Contingencies, 15$ 632,2a Interest during construction 105 .MX TOTAL $5,374,00( ANNUAL COSTS Interest, l& % 215, OCX Amortization, 40-year sinking fund at U% 56,50( Operation and maintenance 5. OCX TOTAL $ 276, 50( C-16 ESTIMATED COST OF FERNDALE DAM AND RESERVOIR WITH STORAGE CAPACITY OF 24,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,150 feet, U.S.G.S. datura Elevation of crest of spillway: 1,120 feet Height of dam to spillway crest, above stream bed: 210 feet Capacity of reservoir to crest of spillway: 24,000 acre-feet Capacity of spillway with 5-foot freeboard: 37,000 second-feet t • Unit : Item Quantity price : Cost CAPITAL COSTS Dam Exploration lump sum $ 40,000 Diversion tunnel 15-foot diameter 1,250 lin.ft. $386. 00 482,500 Portal excavation 20,200 cu.yd. 0.80 16,200 Concrete plug 260 cu f yd. 30.00 7,800 Diversion of stream and dewatering of foundation lump sum 10,000 Stripping topsoil 37,000 cu.yd. 0.60 22,200 Foundation excavation Abutment 349,100 cu.yd. 1.10 384,000 Channel 25,200 cu.yd. 0.60 15,100 Embankment Impervious 1,757,400 cu.yd. 0.70 1,230,200 Pervious 2,343,900 cu.yd. 0.45 1,054,800 Rock riprap 56,830 cu.yd. 4.00 227,300 Drilling grout holes 7,440 lin.ft. 3.00 22,300 Pressure grouting 4,960 cu.ft. 4.00 19,800 ^3,532,200 Spillway Excavation 160,800 cu.yd. 2.00 321,600 Concrete Weir and cutoff 970 cu.yd. 35.00 34,000 Floor 1,270 cu.yd. 30.00 38,100 Walls 590 cu.yd. 40.00 23,600 Reinforcing steel 220,600 lbs. 0.15 33.100 450,400 Outlet Works Inlet structure concrete Inlet structure excavation Steel pipe 60-inch dia. Reinforcing steel High pressure slide gate Needle valve 48-inch dia. Miscellaneous metal work Control house, etc. 300 cu.yd. 400 cu.yd. 326,500 lbs. 41,000 lbs. 35,000 lbs. 60.00 6.00 0.28 0.15 lump sum lump sum 0.40 lump sum 18,000 2,400 91,400 6,200 25,000 18,000 14,000 11.000 186,000 C-17 ESTIMATED COST OF FERNDALE DAM AND RESERVOIR WITH STORAGE CAPACITY OF 24,000 ACRE-FEET (Continued) : : Unit : Item ; Quantity : price : Cost CAPITAL COSTS Reservoir Land acquisition lump sum 294,200 Improvements lump sum 641,900 State road relocation lump sum 420,000 Clearing 340 acres % 150.00 51.000 frl.407.10C Subtotal ^5,57 5, 70C Administration and engineering, 10$ $ 557, 60C Contingencies, 15$ 836, 40( Interest during construction 278 .8 CX TOTAL $7,248,50< ANNUAL COSTS Interest, k% *> 289,90' Amortization, 40-year sinking fund at k% 76,30' Operation and maintenance 6.50 TOTAL 4 372,70 C-18 ESTIMATED COST OF FERNDALE DAK AND RESERVOIR WITH STORAGE CAPACITY OF 34,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,180 feet, U.5.G.S. datum Elevation of crest of spillway: 1,150 feet Height of dam to spillway crest, above stream bed: 240 feet Capacity of reservoir to crest of spillway: 34,000 acre-feet Capacity of spillway with 5-foot freeboard: 37,000 second-feet Item Quantity Unit price Cost CAPITAL COSTS Dam Exploration lump sum $ 40,000 Diversion tunnel 15-foot diameter 1,600 lin.ft. $ 386.00 617,600 Portal excavation 12,760 cu.yd. 0.80 10,200 Concrete plug 260 cu.yd. 30.00 7,800 Diversion of stream and dewatering of foundation lump sum 10,000 Stripping topsoil 68,300 cu.yd. 0.60 41,000 Foundation excavation Abutment 423,000 cu.yd. 1.10 465,300 Channel 29,600 cu.yd. 0.60 17,800 Embankment Impervious 2,303,000 cu.yd. 0.70 1,612,100 Pervious 4,031,800 cu.yd. 0.45 1,814,300 Rock riprap 82,220 cu.yd. 4.00 328,900 Drilling grout holes 7,920 lin.ft. 3.00 23,800 Pressure grouting 5,280 cu . f t . 4.00 21,100 15,009,900 Spillway Excavation 363,820 cu.yd. 2.00 727,600 Concrete Weir and cutoff 1,260 cu.yd. 35.00 44,100 Floor 2,110 cu.yd. 30.00 63,300 Walls 1,630 cu.yd. 40.00 65,200 Reinforcing steel 340,500 lbs. 0.15 51,100 951,300 Outlet Works Inlet structure concrete 300 cu.yd. 60.00 18,000 Inlet structure excavation 400 cu . yd . 6.00 2,400 Steel pipe 60-inch dia. 381,600 lbs. 0.28 106,800 Reinforcing steel 41,000 lbs. 0.15 6,200 High pressure slide gate lump sum 25,000 Needle valve 48-inch dia. lump sum 18,000 Miscellaneous metal work 40,000 lbs. 0.40 16,000 Control house, etc. lump sum 11,000 203,400 c-19 ESTIMATED COST OF FERNDALE DaM AND RESERVOIR WITH STORAGE CAPACITY OF 34,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Reservoir Land acquisition Improvements State road relocation Clearing Subtotal Admin Let ration and engineering, 10$ Co- , .oir\£snoies J 15% Intfcrost during construction TOTAL lump sum $ 294,200 lump sum 641,900 450 acres lump sum $ 150.00 420,000 67.500 frl.423.60t $7,588,20 $ 758,80' 1,138,20' -j:&4a $9,864,60( ANNUAL COSTS Interest/ k% Amortization, 40-year sinking fund at k% Operation and maintenance TOTAL % 394,60 103,80 7,00 $ 505,4C C-20 ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR WITH STORAGE CAPACITY OF 35,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 3,400 feet, Santa Clara Water Conservation District datum, 1932 Elevation of crest of spillway: 3,378 feet Height of dam to spillway crest, above stream bed: 178 feet Capacity of reservoir to crest of spillway: 35,000 acre-feet Capacity of spillway with 5-foot freeboard: 50,000 second-feet : * Unit Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ 40,000 Diversion of stream and dewatering of foundation lump sum 10,000 Stripping topsoil 33,150 cu.yd. $ 0.50 16,600 Foundation excavation Abutment 63,630 cu.yd. 1.60 101,800 Channel 45,840 cu.yd. 0.60 27,500 Embankment Impervious 655,560 cu.yd. 0.74 485,100 Random 1,264,070 cu.yd. 0.58 733,200 Rock riprap 35,200 cu.yd. 4.00 140,800 Gravel fill, pervious drain 19,100 cu.yd. 5.25 100,300 Drilling grout holes 4,380 lin.ft. 3.00 13,100 Pressure grouting 2,920 cu .ft . 4.00 11,700 Slope stabilization, planting 7.5 acres 1,000.00 7,500 .1p1.687.600 Spillway Excavation, unclassified 343,900 cu.yd. 2.00 687,800 Concrete Weir and cutoff 920 cu.yd. 35.00 32,200 Floor 1,930 cu.yd. 30.00 57,900 Walls 690 cu.yd. 40.00 27,600 Reinforcing steel 341,700 lbs. 0.15 51.300 856.800 Outlet Works Excavation Inlet structure 300 cu.yd. 5.00 1,500 Conduit trench 8,890 cu.yd. 6.00 53,300 Concrete Inlet structure 220 cu.yd. 60.00 13,200 Conduit encasement 2,960 cu.yd. 40.00 118,400 Reinforcing steel 152,400 lbs. 0.15 22,900 Miscellaneous metal work 32,000 lbs. 0.40 12,800 C-21 ESTIMATED COST OF COLD SPRING DAM AND R~SLRVOIR V/TTH STORAGE CAPACITY OF 35,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Outlet Works (Continued) Steel pipe ^-inch dia. High pressure slide gate U8" Howell -Bunger valve Control house, etc. 221,000 lbs. ft 0.28 ',? 61,900 lump sura 25,000 lump sum 12,000 lump sum 9,000 330,000 Reservoir Land acquisition Clearing Access road Subtotal Administration and engineering, 10$ Contingencies, X$% Interest during construction TOTAL 760 acres lump sum 50.00 lump sum 25,000 38,000 110,000 103,000 -^2,977,1*00 % 297,700 UU6,600 7U.UQQ ';;3,796,100 ArJNUAL COSTS Interest, k% Amortization, kO-year sinking fund at h% Operation and maintenance •*> 151,800 39,900 7,500 TOTAL 199,200 C-22 ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR 17ITH' STORAGE CAPACITY OF 1*3,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam; 3>!il0 feet, Santa Clara Water Conservation District datum, 1932 Elevation of crest of spillway: 3,390 feet Height of dam to spillway crest, above stream bed: 190 feet Capacity of reservoir to crest of spillway: U3,000 acre-feet Capacity of spillway with 5-foot freeboard: £0,000 second-feet * • • Unit : Item : Quantity : price : Cost • CAPITAL COSTS Dam Exploration lump sum v Uo,ooo Diversion of stream and dewatering of foundation lump sum 10,000 Stripping topsoil 35,000 cu.yd. $ 0.50 17,500 Foundation excavation Abutment 85,800 cu.yd. 1.60 137,300 Channel 67,600 cu.yd. 0.60 J|0,600 Embankment Impervious 852,000 cu.yd. OM 630,500 Random l,39li,500 cu.yd. 0.58 808,800 Rock riprap 39,500 cu.yd. h.00 158,000 Gravel fill, pervious drain • 19,900 cu.yd. 5.25 iok,5oo Drilling grout holes U,620 lin.ft. 3.00 13,900 Pressure grouting 3,080 cu.ft. li.00 12,300 Slope stabilization, planting 8.0 acres 1,000.00 8,000 vl,98l,U00 Spillway Excavation, unclassified 370,000 cu.yd. 2.00 71*0,000 Concrete Weir and cutoff 1,100 cu.yd. 35.00 38,500 Floor • 1,900 cu.yd. 30.00 57,000 , Walls 610 cu.yd. ho. do ' 2lx,hOQ Reinforcing steel 371,200 lbs. 0.15 55,700 915,600 Outlet Works Excavation Inlet structure 300 cu.yd. 5.oo 1,500 Conduit trench 9,030 cu.yd. 6.00 5h,200 Concrete Inlet structure 220 cu.yd. 60.00 13,200 Conduit encasement 3,010 cu.yd. Uo.oo 120,1+00 Reinforcing steel 15U,300 lbs. o.i5 23,100 c-23 ESTIMATED COST OF COLD SPRING DAM. AJJD RLSLRVOIR VjITH STORAGE CAPACITY OF U3,000 ACRE-FEET (Continued) UniT price Item Cost CAPITAL COSTS Outlet v;orks (Continued) Liiscellaneous metal work Steel pipe 60-inch dia. High pressure slide gate 1*8" Howell-Bunger valve Control house, etc. 32,000 273,500 lbs. lbs. $ 0.1*0 0.28 lump sum lump sum lump sum $ 12,800 76,600 25,000 12,000 9,000 v 3^7,800 Reservoir Land acquisition Clearing State road relocation Access road 850 acres lump sura 50.00 lump sum lump sura 25,000 ii2,500 1,050,000 U0,000 1,157,500 Subtotal s^,UO2,300 Administration and engineering 3 Contingencies, 1$% Interest during construction 102 $ W;0,200 660,300 110,000 TOTAL &, 612, 800 +■• m m <■ i. ANNUAL COSTS a Interest, Amortization, liO-year sinking fund at k% Operation and maintenance TOTAL $ 22^,500 59,000 8,000 s? 291,500 ■■ m , 1 11 ■ !» — C-2U ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR " WITH STORAGE CAPACITY OF 77,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 3,450 feet, Santa Clara Water Conservation District datum, 1932 Elevation of crest of spillway: 3,430 Height of dam to spillway crest, above stream bed: 230' feet Capacity of reservoir to crest of spillway: 77,000 acre-feet Capacity of spillway with 5-foot freeboard: 50 , 000 second feet : : Unit : Item Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ 45,000 Diversion tunnel 16-foot diameter 1,520 lin.ft. $ 460.00 699,200 Portal excavation 3,550 cu.yd. 1.50 5,300 Concrete plug 370 cu.yd. 30.00 11,100 Diversion of stream and dewatering of foundation lump sum 20,000 Stripping topsoil 37,400 cu.yd. 0.50 18,700 Foundation excavation Abutment 98,100 cu.yd. 1.60 157,000 Channel 80,100 cu.yd. 0.60 48,100 Embankment Impervious 1 ,281,200 cu.yd. 0.80 1,025,000 Random 2 ,121,800 cu.yd. 0.58 1,230,600 Rock riprap 50,640 cu.yd. 4.00 202,600 Gravel fill, pervious drain 29,1*00 cu.yd. 5.25 i&,Uoo Drilling grout holes 5,160 lin.ft. 3.00 15,500 Fressure grouting 3,440 cu . f t . 4.00 13,800 Slope stabilization, planting 10.7 acres 1,000.00 10,700 &3.6S7.000 Spillway Excavation, unclassified 213,100 cu.yd. 2.00 426,200 Concrete Weir and cutoff 1,210 cu.yd. 35.00 42,400 Floor 1,850 cu.yd. 30.00 55,500 Walls 550 cu.yd. 40.00 22,000 Reinforcing steel 281,900 lbs. 0.15 42,300 588.400 Outlet Works Inlet structure concrete 300 cu.yd. 60.00 18,000 Inlet structure excavation 400 cu.yd. 5.00 2,000 Steel pipe 60-inch dia. 322,200 lbs. 0.28 90,200 Reinforcing steel 41,000 lbs. 0.15 6,200 High pressure slide gate lump sum 25,000 c-25 ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR WITH STORAGE CAPACITY OF 77, COO ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Outlet Works (Continued) 54" Howell-Bunger valve Miscellaneous metal work Control house, etc. Reservoir Land acquisition Clearing State road relocation Access road Subtotal Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL 35,000 lbs. 1,140 acres lump sum & \ 0.40 lump sum 18,000 14,000 11 , 300 184,700 lump sum 25,000 50.00 57,000 lump sum 1,050,000 lump sum 40.000 1.172,000 ^5,602,100 $ 560,200 840,300 280.100 ^7,282,700 ANNUAL COSTS Interest, U% Amortization, 40-year sinking fund at U% Operation and maintenance TOTAL 291,300 76,600 10.000 $ 377,900 C-26 ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 3,472 feet, Santa Clara Water Conservation District datum, 1932 Elevation of crest of spillway: 3,452 feet Height of dam to spillway crest, above stream bed: 252 feet Capacity of reservoir to crest of spillway: 100,000 acre-feet Capacity of spillway with 5-foot freeboard: 50,000 second-feet : : Unit Item Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum & 50,000 Diversion tunnel 16-foot diameter 1,520 lin.ft. $ 460.00 699,200 Portal excavation 3,600 cu.yd. 1.50 5,400 Concrete plug 370 cu.yd. 30.00 11,100 Diversion of stream and dewatering of foundation lump sum 22,000 Stripping topsoil 48,860 cu.yd. 0.50 24,400 Foundation excavation Abutment 132,600 cu.yd. 1.60 212,200 Channel 119,200 cu.yd. 0.60 71,500 Embankment Impervious 1 ,534,700 cu.yd. 0.83 1,273,800 Random 3 ,034,400 cu.yd. 0.60 1,820,600 Rock riprap 64,140 cu.yd. 4.00 256,600 Gravel fill, pervious drain 38,800 cu.yd. 5.25 203,700 Drilling grout holes 5,520 lin.ft. 3.00 16,600 Pressure grouting 3,680 cu.ft. 4.00 14,700 Slope stabilization, planting 13.3 acres 1,000.00 13.300 GIi. 69^. 100 Spillway Excavation, unclassified 185,800 cu.yd. 2.00 371,600 Concrete Weir and cutoff 1,230 cu.yd. 35.00 43,100 Floor 1,800 cu.yd. 30.00 54,000 Walls 570 cu.yd. 40.00 22,800 Reinforcing steel 281,400 lbs. 0.15 42,200 533.700 Outlet Works Inlet structure concrete 300 cu.yd. 60.00 18,000 Inlet structure excavation 400 cu.yd. 5.00 2,000 Steel pipe 60-inch dia. 322,200 lbs. 0.28 90,200 C-27 ESTIMATED COST OF COLD SPRING DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Continued Item Quantity Unit price Cost CAPITAL COSTS Outlet Works (Continued) Reinforcing steel Ul, 000 lbs. $ 0.15 $ 6,200 High pressure slide gate lump sum 25,000 54" Howell-Bunger valve lump sum 18,000 Miscellaneous metal work 35,000 lbs. O.I4O 1)4,000 Control house, etc. lump sum 11,300 $ 181;, 70C Reservoir Land acquisition lump sum 25,000 Clearing 1,290 acres 50.00 6U,500 State road relocation lump sum 1 ,050,000 Access road lump sum 1*0,000 1,179,50* Subtotal $6,593,00< Administration and engineering, 10$ $ 659,30* Contingencies, 1$% 989,00* Interest during construction 329J0( TOTAL 08,571,00* ANNUAL COSTS Interest, h% Amortization, l*0-year sinking fund at h% Operation and maintenance 3U2,80* 90,2D 12,50 TOTAL *► 1*1*5,501 C-2&- ESTIMATED COST OF TOPATOPA DM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 2,395 feet, U.S.G.S. datum Elevation of crest of chute spill- way: 2,360 feet Elevation of crest of overpour spillway: 2,380 feet Elevation of top of gates, chute spillway: 2,380 feet Height of dam to top of gates, above stream bed: 280 feet Capacity of reservoir to top of gates: 50,000 acre-feet Capacity of spillways with 5-foot freeboard: 82,000 second-feet Item : Quantity : Unit : price : Cost CAPITAL COSTS Dam Concrete Excavation Drilling grout holes Pressure grouting Diversion of stream Exploration 287,000 cu.yd. 100,000 cu.yd. 9,000 lin. ft. 7,000 cu.ft. $ 18.00 $5,166,000 3.00 300,000 3.00 27,000 4.00 28,000 lump sum 50,000 lump sum 35,000 ^5,606,000 Chute spillway Concrete Excavation Reinforcing steel Gates and hoists 4,500 155,000 380,000 3 cu.yd. 40.00 cu.yd. 4.00 lbs. 0.15 each 25,000.00 180,000 620,000 57,000 75,000 932.000 Outlet Works lump sum 60,000 Reservoir Land acquisition Roads to dam Clearing lump sum lump sum lump sum 25,000 400,000 20,000 445.000 Subtotal &7,-043,000 Administration and engineering Contingencies, 15$ Interest during construction , 10$ $ 704 000 1,056,000 3^2,000 TOTAL 5p9,155,00O ANNUAL COSTS Interest, k% Amortization, i|0-year sinking Operation and maintenance fund at k% $ 366,200 96,300 20,000 TOTAL $ 482,500 C-29 ESTIMATED COST OF TOPATOPa DAM AND RESERVOIR WITH STORAGE CAPACITY OF 75,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 2,437 feet, U.S.G.S. datum Elevation of crest of chute spillway: 2,400 feet Elevation of crest of overpour soillway: 2,420 feet Elevation of top of gates, chute spillway: 2,420 feet Height of dam to top of gates, above stream bed: 322 feet Capacity of reservoir to top of gates: 75,000 acre-feet Capacity of spillways with 5-foot freeboard: 82,000 second-feet Item : Quantity : Unit : : price : Cost CAPITAL COSTS Dam Concrete Excavation Drilling grout holes Pressure grouting Diversion of stream Exploration 412,000 190,000 11,000 9,000 cu.yd. cu.yd. lin.ft cu . f t . % ia.oo $7,416,000 3.00 570,000 3.00 33,000 4.00 36,000 lump sum 50,000 lump sum 35,000 &8 . 140 . OCX Chute spillway Concrete Excavation Reinforcing steel Gates and hoists 4,300 146,000 360,000 3 cu.yd. cu.yd. lbs. each 40.00 4.00 0.15 25,000.00 172,000 584,000 54,000 75,000 885. OCX Outlet Works lump sum 60,00( Reservoir Land acquisition Roads to dam Clearing lump sum lump sum lump sum 25,000 4 00, 000 30,000 455,00( Suhtotal $9,54O,O0C Administration and engineering, 10/o Contingencies, 15% Interest during construction % 954, 00C 1,431,00C 596,0_0C TOTAL $12,521, 00C ANNUAL COSTS Interest, U% Amortization, 40-year sinking Operating and maintenance fund at k% % 500,800 131,700 20 f 000 TOTAL $ 652,500 C-30 ESTIMATED COST OF TOPATOPA DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 2,470 feet, U.S.G.S. datum Elevation of crest of chute spill- way: 2,435 feet Elevation of crest of overpour spillway: 2,455 feet Elevation of top of gates, chute spillway: 2,455 feet Height of dam to top of gates, above stream bed: 355 feet Capacity of reservoir to top of gates: 100,000 acre- feet Capacity of spillways with 5-foot freeboard: 82,000 second-feet Item Quantity Unit price Cost CAPITAL COSTS Dam Concrete Excavation Drilling grout holes Pressure grouting Diversion of stream Exploration Chute spillway Concrete Excavation Reinforcing steel Gates and hoists Outlet Works Reservoir Land acquisition Roads to dam Clearing Subtotal Administration and engineering, 10$ Contingencies, 15$ • Interest during construction TOTAL 522,000 cu.yd. 275,000 cu.yd. 13,000 lin ft. 11,000 cu.ft. i 18.00 3.00 3.00 4.00 lump sum lump sum 4,100 cu.yd. 40.00 122,000 cu.yd. 4.00 350,000 lbs. 0.15 3 each 25,000.00 lump sum lump sum lump sum lump sum >, 396, 000 825,000 39,000 44,000 50,000 35.000 $10,389,000 164,000 488,000 52,500 75.000 62,500 400,000 40,000 779,500 60,000 502. 500 $01,731,000 $ 1,173,000 1,760,000 880.000 $i5,5Wt,ocu ANNUAL COSTS Interest, k% Amortization, 40-year sinking fund at Operation and maintenance TOTAL # 621,800 163,500 20.000 % 805,300 C-31 ESTIMATED COST OF HAMMEL DAM AND RESERVOIR WITH STORAGE CAPACITY OF 25,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of damr 1,125 feet, U.S.G.S. datum Elevation of top of gates: 1,120 feet Height of dam to top of gates, above stream bed: 330 feet Capacity of reservoir to top of gates: 25,000 acre-feet Capacity of spillway with 5-foot freeboard: 90,000 second-feet • • • Unit : Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum f» 90,000 Diversion tunnel 7-foot diameter 1*90 lin.ft. & 11*0.00 68,600 Portal excavation 2,000 cu.yd. 2.00 1*,000 Concrete plug Uo cu.yd. 30.00 1,200 Diversion of stream and dewatering of foundation lump sum 1*0,000 Stripping 179,1*00 cu.yd. 3.00 538,200 Mass concrete 530,700 cu.yd. 15.00 7,960,500 Cooling concrete 530,700 cu.yd. 0.50 265,300 Parapet wall concrete 180 cu.yd. 50.00 9,000 Drilling grout holes 3,300 lin.ft. I*. 00 13,200 Pressure grouting 2,200 cu.ft. 3.00 6,600 18,996,600 Spillway Reinforced concrete Walls 1,1*90 cu.yd. 1*0.00 59,600 Piers 7U0 cu.yd. 50.00 37,000 Gates and hoists 928,000 lbs. 0.32 297,000 Reinforcing steel 51*9,000 lbs. 0.15 82,300 Bridge lump sum 20,000 1*95,900 Outlet Works Ring seal gates 120,000 lbs. o.U5 51*,ooo Needle valve l*8-inch dia. 32,000 lbs. 0.55 17,600 Steel pipe 5h-inch dia. 75,000 lbs. 0.28 21,000 Trashrack steel 90,000 lbs. 0.1*0 36,000 Miscellaneous metal work 371,000 lbs. o.i*o 11*8,1*00 277,000 Reservoir Access road 2 miles 50,000.00 100,000 Clearing 210 acres 150.00 31,500 Land and improvements lump sum 12,500 ll*i*,000 Subtotal •39,913,500 Administration and engineer ir ig, io# $ 991,300 Contingencies, 15$ 1,1*87,000 Interest during construction ., 1*95,700 TOTAL $12,887,500 C-32 ESTIMATED COST OF HAMEL DA11 AND RESERVOIR WITH STORAGE CAPACITY OF 2£,000 ACRE-FEET (Continued) : : Unit : Item ; Quantity : price : Cost ANNUAL COSTS Interest, k% $ £l£,£00 Amortization, liO-year sinking fund at h% 135>,600 Operation and maintenance 1$,000 TOTAL % 666,100 C-33 ESTIMATED COST OF HAMMEL DAM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,223 feet, U.S.G.S. datum Elevation of top of gates: 1,218 feet Height to top of gates, above stream bed: U28 feet Capacity of reservoir to top of gates: £0,000 acre-feet Capacity of spillway with 5-foot freeboard: 90,000 second-feet Item Quantity Unit price Cost CAPITAL COSTS Dam Exploration Diversion tunnel 7-foot diameter Portal excavation Concrete plug Diversion of stream and de- watering of foundation Stripping Mass concrete 1 Cooling concrete 1 Parapet wall concrete Drilling grout holes Pressure grouting Spillway Reinforced concrete Walls Piers Gates and hoist Reinforcing steel Bridge Outlet Works Ring seal gates Needle valve U8-inch dia. Steel pipe 5^-inch dia. Trashrack steel Miscellaneous metal work Reservoir Access road Clearing Land and improvements Subtotal lump sum $ 110,000 560 lin.ft. $ lUO.OO 78,iiOO 2,000 cu.yd. 2.00 ii,000 I4O cu.yd. 30.00 1,200 lump sum U0,000 286,100 cu.yd. 3-00 858,300 ,067,900 cu.yd. 15.00 16,018,500 ,067,900 cu.yd. 0.50 533,900 320 cu.yd. 50.00 16,000 14,920 lin.ft. ii.00 19,700 3,280 cu.ft. 3-00 9,800 $17,689,80' 2,120 cu.yd. iiO.OO 81*,800 7U0 cu.yd. 50.00 37,000 928,000 lbs. 0.32 297,000 725,000 lbs. 0.15 108,700 lump sum 20,000 120,000 lbs. 0.U5 5U,000 32,000 lbs. 0.55 17,600 12^,000 lbs. 0.28 3ii,70O 90,000 lbs. o.l;0 36,000 7ii7,500 lbs. 0.U0 299,000 2 miles 50,000.00 100,000 320 acres 150.00 h8,oco lump sum 12,500 5147,50 14*1,30 160,50 $18,839,10 c-3l ESTIMATED COST OF HALOEL DAM AND RESERVOIR Y/ITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Continued) : : Unit : Item : Quantity : price : Cost IlPITAL COSTS ilministration and engineering, 10$ v 1,883,900 (mtingencies, 1$% 2,825,900 iiterest during construction 9U2,OQO TOTAL ^21*, 1*90,900 JNUAL COSTS :iterest, h% $ 979,600 -aortization, liO-year sinking fund at h% 257,600 (>eration and maintenance 15,000 TOTAL $ 1,252,200 C-35 ESTIMATED COST OF UPPER BLUE POINT DAM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Based on prices prevailing in spring of 1953) 1,320 Elevation of crest of dam: feet, U.S.G.S. datum Elevation of crest of spillway: 1,295 feet Height of dam to spillway crest, above stream bed: 205 feet Item Capacity of reservoir to crest of spillway: 50.000 acre-feet Capacity of spillway with 5-foot freeboard: 100,000 second-feet Quantity Unit price Cost CAPITAL COSTS Dam Exploration lump sum i | 50,000 Diversion tunnel 20-foot diameter 1,250 lin.ft. $ 500.00 625,000 Portal excavation 4,000 cu.yd. 0.70 2,800 Concrete plug 730 cu.yd. 30.00 21,900 Diversion of stream and dewatering of foundation lump sum 20,000 Stripping topsoil 53,000 cu.yd. 0.40 21,200 Foundation excavation 679,500 cu.yd. 0.90 611,600 Embankment Impervious 1,867,500 cu.yd. 0.70 1,307,300 Pervious 3,118,900 cu.yd. 0.50 1,559,500 Rock riprap 77,000 cu.yd. 4.00 308,000 Drilling grout holes 6,660 lin.ft. 3.00 20,000 Pressure grouting 4,440 cu . f t . 4.00 17.800 ^4, 565, 10C Spillway Excavation 599,900 cu.yd. 2.25 1,349,800 Concrete Weir and cutoff 1,860 cu.yd. 30.00 55,800 Floor 4,080 cu.yd. 25.00 102,000 Walls 1,840 cu.yd. 40.00 73,600 Reinforcing steel 624,100 lbs. 0.15 93,600 1,674,80< Outlet Works Tower concrete 660 cu.yd. 80.00 52,800 Tower excavation 400 cu.yd. 5.00 2,000 Steel pipe 72-in. dia. 336,600 lbs. 0.28 94,200 Tower inlet valve 36-in. dia. 4 each 3,600.00 14,400 Howell- Bunger valve 48-in. dia. 1 each 12,000.00 12,000 Needle valve 48-in. dia. 1 each 18,000.00 18,000 Sluice gate lump sum 25,000 Miscellaneous metal work 32,000 lbs. 0.40 12,800 Control house, etc. lump sum 10.000 241, 20( c-36 ESTIMATED COST OF UPPER BLUE POINT DAM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Reservoir Land acquisition Clearing Access Road Subtotal lump sum $ 33,300 640 acres I 50.00 32,000 lump sum 15.000 ft 80.300 $6,561,400 Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL $ 656,200 984,200 328.000 $8,529,800 ANNUAL COSTS Interest, U% Amortization, 40-year sinking fund at k% Operation and maintenance TOTAL $ 341,200 89,700 $ 438,400 C-37 ESTIMATED COST OF BLUE POINT DAM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,305 feet, U.S.G.S. Datum Elevati on -?f crest of spillway: 1,280 feet Height of dam to spillway crest, above stream bed: 215 feet Capacity of reservoir to crest of spillway: 50,000 acre-feet Capacity of spillway with 5-foot freeboard: 100,000 second-feet j • Unit : Item : Quantity : price : Co st CAPITAL COSTS Dam Exploration lump sum $ 50,000 Diversion of stream and dewatering of foundation lump sum 40,000 Stripping topsoil 33,200 cu.yd. $. 0.40 13,300 Foundation excavation 733,100 cu.yd. 0.90 659,800 Embankment Impervious 1,435,800 cu.yd. 0.70 1,005,100 Pervious 2,061,900 cu.yd. 0.50 1,031,000 Rock riprap 55,400 cu.yd. 4.00 221,600 Drilling grout holes 4,830 Lin. ft 3.00 14,500 Pressure grouting 3,220 cu . f t . 4.00 12,900 iSi3,048,20C Spillway Portal excavation 300,000 cu.yd. 2.25 675,000 Tunnel excavation 60,000 cu.yd. 15.00 900,000 Concrete Weir 4,500 cu.yd. 30.00 135,000 Walls and paving 2,500 cu.yd. 40.00 100,000 Tunnel lining 12,000 cu.yd. 50.00 600, OCO Reinforcing steel 2,000,000 lbs. 0.15 300,000 2,710,OOC Outlet Works Excavation Tower foundation 380 cu.yd. 5.00 1,900 Conduit trench 5,080 cu.yd. 6.00 30,500 Concrete Tower 660 cu.yd. 80.00 52,800 Pipe encasement 3,340 cu.yd. 40.00 133,600 Reinforcing steel 283,400 lbs. 0.15 42,500 Steel pipe, 72-inch dia. 359,600 lbs. 0.28 100,700 Gate valve 36-inch dia. 4 each 3,600.00 14,400 Howell-Bunger valve 48-inch dia. 1 each 12,000.00 12,000 Needle valve 48-inch dia. 1 each 18,000.00 18,000 Sluice gate 1 each 20,000.00 20,000 Miscellaneous metal work 33,000 lbs. 0.40 13,200 Control house, etc* lump sum 10,000 449/60C C-38 ESTIMATED COST OF BLUE POINT DAM AMD RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Reservoir Land acquisition Clearing Access Road Subtotal 640 acres lump sum $> I 50.00 lump sum Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL 33,300 32,000 12,200 $ 77,500 $6,285,300 $ 628,500 942,800 314,300 $8,170,900 ANNUAL COSTS Interest, U% Amortization, 40-year sinking fund at k% Operation and maintenance TOTAL % 326,800 86,000 7,500 % 420,300 C-39 ESTIMATED COST OF DEVIL CANYON DM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACaiE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,21j5 feet, U.S.G.S. datum Elevation of crest of spillway: 1,220 feet Height of dam to spillway crest, above stream bed: 21^0 feet Capacity of reservoir to crest of spillway: 100,000 acre-feet Capacity of spillway with 5-foot freeboard: 102,00 second-feet • : Unit Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ U0,000 Diversion tunnel 21-foot diameter 1,750 lin.ft. $ 510.00 892,500 Portal excavation 13,300 cu.yd. 1.50 19,900 Concrete plug 730 cu.yd. 30.00 21,900 Diversion of stream and dewatering of foundation lump sum 50,000 Stripping tops oil 57,200 cu.yd. o.Uo 22,900 Foundation excavation Abutment 105,300 cu.yd. 1.1*0 1U7,I»00 Channel 905,000 cu.yd. 0.60 5U3,ooo Embankment Impervious 2,599, U00 cu.yd. Pervious 3, 761*., 100 cu.yd. Rock riprap 80,000 cu.yd. Drilling grout holes 6,360 lin.ft. Pressure grouting U*2U0 cu.ft. Spillway Excavation Concrete Weir and cutoff Floor Walls Reinforcing steel Outlet Works Inlet structure concrete Inlet structure excavation Steel pipe 72-in. dia. Reinforcing steel High pressure slide gate Needle valve 60-in. dia. 1 each Miscellaneous metal work 32,000 lbs. Control house, etc. 1,288,300 cu.yd. 5,220 cu.yd. 8,i|60 cu.yd. 5,180 cu.yd. 1,573,700 lbs. 300 cu.yd. 1|00 cu.yd. il50,100 lbs. 30,000 lbs. 0.65 1,689,600 0.U5 1,693,800 U.00 320,000 3.00 19,100 U.oo 17,000 $5,^77,ia 2.00 2,576,600 35-00 30.00 ko.oo 0.15 60.00 5.00 0.28 0.15 lump sum 27,500.00 o.Uo lump sum 182,700 253,800 207,200 236,100 18,000 2,000 126,000 l*,5oo 25,000 27,500 12,800 10,000 3,U56,liO( 225,80< C-40 ESTIMATED COST OF DEVIL CANYON DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Reservoir Land acquisition Clearing Subtotal lump sum $ 110,300 1,050 acres $ 50.00 52,500 $ 162,800 Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL $9,322,100 $ ' 932,200 1,39S, 300 466,100 $12,118,700 ANNUAL COSTS Interest, l+% Amortization, 40-year sinking fund at k% Operation and maintenance TOTAL % 484,700 127,500 12 , 500 $ 624,700 C-41 ESTIMATED COST OF DEVIL CANYON DAM AND RESERVOIR WITH STORAGE CAPACITY OF 150,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,290 feet, U.S.G.S. datum Elevation of crest of spillway: 1,265 feet Height of dam to spillway crest, above stream bed: 285 feet Capacity of reservoir to crest of spillway: 150,000 acre- feet Capacity of spillway with 5-foot freeboard: 102,000 second- feet J : Unit : Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ 40,000 Diversion tunnel 21- foot diameter 2,130 lin.ft. , $ 510.00 1,086,300 Portal excavation 12,000 cu.yd. 1.50 18,000 Concrete plug 730 cu.yd. 30.00 21,900 Diversion of stream and dewatering of foundation lump sum 50,000 Stripping topsoil 91,860 cu.yd. 0.40 36,700 Foundation excavation Abutment 104,400 cu.yd. 1.40 146,200 Channel 1,036,300 cu.yd. 0.60 621,800 Embankment Impervious 3,421,500 cu.yd. O.65 2,224,000 Pervious 6,467,400 cu.yd. 0.45 2,910,300 Rock riprap 112,840 cu.yd. 4.00 451,400 Drilling grout holes 7,080 lin.ft. 3.00 21,200 Pressure grouting 4,720 cu . f t . 4.00 18.900 &7. 646. 700 Spillway Excavation 1,280,100 cu.yd. 2.00 2,560,200 Concrete Weir and cutoff 4,250 cu.yd. 35.00 148,800 Floor 10,520 cu.yd. 30.00 315,600 Walls 5,490 cu.yd. 40.00 219,600 Reinforcing steel 1,727,800 lbs. 0.15 259.200 3.503.400 Outlet Works Tower concrete 850 cu.yd. 80.00 68,000 Tower excavation 400 cu.yd. 5.00 2,000 Steel pipe 72-inch dia. 673,200 lbs. 0.28 188,500 Tower inlet valves 36- in. dia. 5 each 3,600.00 18,000 Howell-Bunger valve, 48-in. dia. 1 each 12,000.00 12,000 Needle valve, 48-in. dia. 1 each 18,000.00 18,000 Sluice gate lump sum 20,000 Miscellaneous metal work 40,000 lbs. 0.40 16,000 Control house, etc. C-42 1 lump sum 10,000 352.500 ESTIMATED COST OF DEVIL CANYON DAM AND RESERVOIR WITH STORAGE CAPACITY OF 150,000 ACRF-FEET (Continued) : : Unit : Item Quantity : , price ; Cost CAPITAL COSTS Reservoir Land acquisition lump sum $ 110,300 Clearing 1,500 acres $ 50.00 75.000 & 185.300 Subtotal $11,687,900 Administration and engineering, 10$ $ 1,168,800 Contingencies, 15% 1,753,200 Interest during construction 876 . 600 TOTAL $15,486,500 ANNUAL COSTS Interest, l& % 619,500 Amortization, 40-year sinking fund at U% 162,900 Operation and maintenance 15.700 TOTAL $ 798,100 C-43 ESTIMATED COST OF SANTA FELICIA DAM AND RESERVOIR WITH STORAGE CAPACITY OF $0,000 ACRE-FEET (Based on prices prevailing in spring 1953) Elevation of crest of dam: 1,030 feet Elevation of crest of spillway: 1,010 feet Height of dam to spillway crest, above stream bed: 11*0 feet Capacity of reservoir to crest of spillway: 50,000 acre-feet Capacity of spillway with 5-foot freeboard: 103,000 second-feet Item : Quantity Unit .price. Cost CAPITAL COSTS Dam Exploration Diversion of stream and dewatering of foundation Stripping tops oil Foundation excavation Abutment Channel Excavation for embankment From borrow pits From stream bed Embankment Impervious 1 Pervious 1 Rock riprap Drilling grout holes Pressure grouting lunp sum $ 50,000 lump sum 30,700 cu.yd. $ 0.1*0 29,1*00 886,1*00 .,686,600 638,700 ,1*66,600 ,571,300 1*1,100 6,21*0 1*,160 cu.yd. cu.yd. cu.yd. cu.yd. cu . yd . cu.yd. cu.yd. lin.ft. cu. ft. 1.1*0 0.55 0.1*7 0.36 0.18 0.12 1*.00 3.00 1*.00 50,000 12,300 la, 200 1*87,500 792,700 301,900 261*, 000 188,600 161*, 1*00 18,700 16,600 Spillway Excavation 1,598,100 cu.yd. 0.90 1,1*38,300 Concrete Weir and cutoff 3,290 cu.yd. 35.00 115,200 Floor 8,590 cu.yd. 30.00 257,700 Walls 3,010 cu.yd. 1*0.00 120,1*00 Reinforcing steel 1,199,800 lbs. 0.15 180,000 Outlet Works Excavation Inlet Structure 300 cu.yd. 5.00 i,5oo Conduit Trench 5,250 cu.yd. 6.00 31,500 Concrete Inlet structure 220 cu.yd. 60.00 13, 200 Conduit encasement 1,750 cu.yd. 1*0.00 70,000 Reinforcing steel 91,200 lbs. 0.15 13,700 Steel pipe 60-inch dia. 159,000 lbs. 0.28 1*1*, 500 Miscellaneous metal work 32,000 lbs. 0.1*0 12,800 High pressure slide gate lump sum 25,000 Needle valve 51*-inch dia. lump sum 20,000 Control house, etc. lump sum 10,000 !,387,900 2,111,600 21*2,200 C-44 ESTIMATED COST OF SANTA FELICIA DAM AND RESERVOIR WITH STORAGE CAPACITY OF 50,000 ACRE-FEET (Continued) Unit price Item Quantity- Cost CAPITAL COSTS teservoir Land acquisition Clearing Road relocation and oil well damage 1,030 acres lump sum $ 50.00 lump sum $ Ui7,000 51,500 350,000 $81*8,500 Subtotal $5,590,200 Administration and engineering, 10$ Contingencies, 1$% Interest during construction TOTAL $ 559,000 838,500 139,80 $7,127,500 ANNUAL COSTS Interest, k% Amortization, ^0-year sinking fund at h% Operation and maintenance TOTAL $285,100 75,000 9,000 $369,100 C-Ii5 ESTIMATED COST OF SANTA FELICIA DAM AND RESERVOIR WITH STORAGE CAPACITY OF 75,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,055 feet Elevation of crest of spillway: 1,035 feet Height of dam to spillway crest, above stream bed: 165 feet Capacity of reservoir to crest of spillway: 75,000 acre-feet Capacity of spillway with 5-foot freeboard: 103,000 second-fee 1 Item CAPITAL COSTS Quantity Unit price Cost Dam 1*2,600 cu.yd, Exploration Diversion tunnel 22-foot diameter 1,080 lin.ft. Portal excavation 18,000 cu.yd. Concrete plug 800 cu.yd. Diversion of stream and dewatering of foundation Stripping topsoil Foundation excavation Abutment 37,100 cu.yd. Channel 989,300 cu.yd. Excavation for embankment From borrow pits 2,198,200 cu.yd. From streambed 1,79U,1*00 cu.yd. Embankment Impervious 1,911,500 cu.yd. Pervious 2,615,500 cu.yd. Rock riprap 59,700 cu.yd. Drilling grout holes 6,960 lin.ft. Pressure grouting 1*,61*0 cu.ft. Spillway Excavation Concrete Weir and cutoff Floor Walls Reinforcing steel Outlet Works Inlet structure concrete Inlet structure excavation Steel pipe 72-inch dia. Reinforcing steel High pressure slide gate Needle valve 60-inch dia. Miscellaneous metal work Control house, etc. 1,03U,100 cu.yd. lump sum I 530.00 1.50 30.00 lump sum 0.1*0 1.1*0 0.55 0.1*7 0.36 0.18 0.12 l*.oo 3.00 h. oo 0.80 3,290 cu.yd. 35.00 8,230 cu.yd. 30.00 2,820 cu.yd. 1*0.00 1,153,100 lbs. 0.15 290 cu.yd. 60.00 i 390 cu.yd. 5.oo 280,500 lbs. 0.28 27,300 lbs. 0.15 lump sum 1 each 27,500.00 32,000 lbs. 0.1*0 lump sum & 50,000 572,1*00 27,000 21*, 000 60,000 17,000 51,900 5W*,ioo 1,033,200 61*6,000 3U*,100 313,900 238,800 20,900 18,600 827,300 115,200 21*6,900 112,800 173,000 17,1*00 2,000 78,500 1*,100 25,000 27,500 12,800 10,000 C-46 ESTIMATED COST OF SANTA FELICIA DAn AND RESERVOIR WITH STORAGE CAPACITY OF 75,000 ACRE-FEET (Continued) Item Quantity Unit price Cost HPITAL COSTS sservoir Land acquisition Clearing Road relocation and oil well damage Subtotal lump sum 1,270 acres $ 50.00 lump sum iministration and engineering, 10% Dntingencies, 15% iterest during construction TOTAL 447,000 63,500 350,000 ^860,500 $6,1471,900 $ 6U7,500 971,200 323,700 $B71H77300 ;JHUAL COSTS .'iterest, k% ,iortization,[iO-year sinking fund at k% Deration and maintenance TOTAL $336,700 88,500 10,000 $U35,200 C-U7 ESTIMATED COST OF SANTA FELICIA DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam* 1,077 feet, U.S.G.S. datum Elevation of crest of spillway: 1,057 feet Height of dam to spillway crest, above stream bed: 187 feet Capacity of reservoir to crest of spillway: 100,000 acre-feet Capacity of spillway with 5-foot freeboard: 103,000 second-feet : : Unit : Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ 50,000 Diversion tunnel 22-foot diameter 1,270 lin.ft. $ 530.00 673,100 Portal excavation 19,800 cu.yd. 1.50 29,700 Concrete plug 890 cu.yd. 30.00 26,700 Diversion of stream and dewatering of foundation lump sum 70,000 Stripping topsoil 92,300 cu.yd. 0.40 36,900 Foundation excavation Abutment 57,700 cu.yd. 1.40 80,800 Channel 1,018,600 cu.yd. 0.55 560,200 Excavation for embankment From borrow pits 2,458,200 cu.yd. 0.47 1 .,155,400 From stream bed 2,492,500 cu.yd. 0.36 897,300 Embankment Impervious 2,137,600 cu.yd. 0.18 384,800 Pervious 3,290,500 cu.yd. 0.12 394,900 Rock riprap 75,740 cu.yd. 4.00 303,000 Drilling grout holes 7,260 lin.ft. 3.00 21,800 Pressure grouting 4,840 cu.ft. 4.00 19,400 ;;>4,704,00( Spillway Excavation 699,100 cu.yd. 0.70 489,400 Concrete Weir and cutoff 3,290 cu.yd. 35.00 115,200 Floor 8,950 cu.yd. 30.00 268,500 Walls 3,190 cu.yd. 40.00 127,600 Reinforcing steel 1,245,700 lbs. 0.15 186,900 1,187.60( Outlet Works Inlet structure concrete 290 cu.yd. 60.00 Inlet structure excavation 390 cu.yd. 5.00 Steel pipe 72-inch dia. 295,800 lbs. 0.28 Reinforcing steel 30,000 lbs. 0.15 High pressure slide gate lump sum Needle valve 60-inch dia. 1 each 27,500.00 Miscellaneous metal work 32,000 lbs. 0.40 Control house, etc. lump sum 17,400 2,000 82,800 4,500 25,000 27,500 12,800 10.000 182, (XX C-48 ESTIMATED COST OF SANTA FELICIA DAM AND RESERVOIR WITH STORAGE CAPACITY OF 100,000 ACRE-FEET (Continued) Item Quantity Unit price Cost CAPITAL COSTS Reservoir Land acquisition Clearing 1,490 acres Road relocation and oil well damage Subtotal Administration and engineering, 10$ Contingencies, 15$ Interest during construction TOTAL lump sum $ 447,000 I 50.00 74,500 lump sum 350.000 $ 871.500 $6,945,100 $ 694,500 1,041,800 347.300 $9,028,700 ANNUAL COSTS Interest, lff> Amortization, 40-year sinking fund at 1$ Operation and maintenance TOTAL % 361,100 95,000 12.500 $ 468,600 C-49 ESTIMATED COST OF DISTRIBUTION SYSTEM FROM CASITAS RESERVOIR (Based on prices prevailing in spring of 1953) Item Quantity Unit price Cost CAPITAL COSTS Main Feeder - Casitas Reservoir to Foster Park Excavation and backfill 12,900 lin.ft. $ 2.80 '4 36,100 Furnish and install 36- inch diameter reinforced concrete pipe 12,900 lin.ft. 16.25 209,600 Ventura River crossing 1,100 lin.ft. 26.75 29,UOO Gate valves lump sum h, 000 Line meters 2 each h, 000. 00 8,000 Blowoff valves 2 each 500.00 1,000 Air valves 2 each iiOO.OO 800 Chlorinator structure lump sum 10,000 Chlorinator equipment lump sum 10,500 Road surfacing 12,900 lin.ft. 1.00 12,900 Concrete in structures 220 cu.yd. 65.00 LU,300 Miscellaneous metal 2,500 lbs. 0.65 1,600 Fire hydrants k each 150.00 600 Right of way lump sum 5,000 Eastside Conduit - Foster Park to Lacrosse 2.15 Excavation and backfill 8,700 lin.ft. 18,700 Furnish and install 27- inch diameter concrete cylinder pipe 8,700 lin.ft. 11.85 103,100 Creek crossing 300 lin.ft. 20.75 6,200 Gate valve - 18-inch dia. 1 each 1,000.00 1,000 Blowoff valves lump sum 1*00 Air valves 2 each 300.00 600 Service outlets 5 each 150.00 800 Concrete structures 50 cu.yd. 65.00 3,300 Miscellaneous metal 1,000 lbs. 0.65 700 Road surfacing 8,700 lin.ft. 0.85 7,1*00 Fire hydrants 2 each 150.00 300 Right of way lump sum 1,000 Eastside Conduit - Lacrosse to Baldwin Road 1.86 Excavation and backfill 18,000 lin.ft. 33,500 Furnish and install 214- inch diameter concrete cylinder pipe 18,000 lin.ft. 10.25 181|,500 Gate valves - 18-inch dia. 3 each 1,000.00 3,000 Line meter lump sum 2,900 Blowoff valves 2 each koo.oo 800 Air valves 2 each 300.00 600 Service outlets 5 each 150.00 800 Concrete structures 80 cu.yd. 65.00 5,200 Miscellaneous metal 2,000 lbs. 0.65 1,300 $ 3k3, 800 110,500 C-50 ESTIMATED COST OF DISTRIBUTION SYSTEM FROM CASITAS RESERVOIR (Continued) Item Quantity Unit price l ist side Conduit - Baldwin Road to Fairview Wye Excavation and backfill Furnish and install 16- : inch diameter concrete cylinder pipe Gate valves - 12-inch dia. Blowoff valves Air valves Service outlets Concrete structures Miscellaneous metal Road surfacing Fire hydrants Pumping plant Right of way 11,1*00 lin.ft. 11,1*00 lin.ft. 1.00 each each each each 80 cu«yd. 1,000 9,000 7 lbs. lin.ft. each 'eek Road Conduit - Lacrosse to Terminal Reservoir Excavation and backfill Furnish and install 16- inch diameter concrete cylinder pipe Gate valves - 12 -inch dia. Line meter Blowoff valves Air valves Service outlets Concrete structures Miscellaneous metal Road surfacing Fire hydrants Highway crossing Reservoir Pumping plant Right of way jper Ojai Conduit Excavation and backfill Furnish and install 12- inch diameter concrete cylinder pipe 1*2,800 lin.ft. 1.00 Cost (JITAL COSTS hstside Conduit - Lacrosse to Baldwin Road (Continued) "Road surfacing 7,500 lin.ft. $ 0.80 Fire hydrants 8 each 150.00 Reservoir lump sum Pumping plant lump sum Right of way lump sum 6,000 1,200 35,000 32,200 15,000 11,1*00 $ 322,000 6.25 71,200 U5o.oo 900 200.00 600 300.00 600 150.00 800 65.00 5,200 0.65 600 0.60 5,Uoo 150.00 1,000 lump sum 27,000 lump sum 1*,000 1-2,800 1*2,800 lin.ft. 6.25 267,500 8 each U5o.oo 3,600 lump sum 2,000 1* each 200.00 800 8 each 300.00 2,1*00 111 each 150.00 2,100 150 cu.yd. 65.00 9,800 3,300 lbs. 0.65 2,100 21*, 1*00 lin.ft. 0.60 Hi, 600 10 each 150.00 i,5oo lump sum 2,500 lump sum 35,000 lump sum 3l*,200 lump sum 7,000 10,200 lin.ft. 0.80 8,200 10,200 lin.ft. U.85 1*9,500 128,700 1*27,900 I c-5i ESTIMATED COST OF DISTRIBUTION SYSTEM FROM CASITAS RESERVOIR (Continued) Unit price Item Quantity Cost CAPITAL COSTS Upper Ojai Conduit (Continued) Gate valves - 10- inch dia. Line meter Blowoff valves Air valves Service outlets Concrete structures Miscellaneous metal Road surfacing Fire hydrants Pumping plant Right of way Cross Tie to Grand Avenue Excavation and backfill Furnish and install 12- inch diameter concrete cylinder pipe Gate valves - 10-inch dia. Line meter Blowoff valves Air valves Service outlets Concrete structures Concrete pipe anchors Miscellaneous metal Road surfacing Fire hydrants Right of way 2 each % 350.00 \ \ 700 lump sum 1,800 2 each 200.00 Uoo 2 each 300.00 600 5 each 150.00 800 75 cu.yd. 65.00 k,900 1,000 lbs. 0.65 600 U,200 lin.ft. 0.55 2,300 3 each 150.00 Uoo lump sum 15,700 lump sum 2,500 U,5oo lin.ft. 0.80 3,600 it, 5oo lin.ft. In 85 21,800 2 each 350.00 700 lump sum 1,800 lump sum 200 2 each 300.00 600 3 each 150.00 1*00 20 cu.yd. 65.00 1,300 20 cu.yd. 30.00 600 1,000 lbs. 0.65 600 U,5oo lin.ft. 0.55 2,500 3 each 150.00 boo lump sum 5oo Baldwin Road - Santa Ana Conduit Excavation and backfill Furnish and install lk- inch diameter concrete cylinder pipe Ventura River crossing Gate valves - 12-inch dia. Line meter Blowoff valves Air valves Service connections Concrete structures Miscellaneous metal Road surfacing Fire Hydrants 11,800 lin.ft. 11,800 lin.ft. 1,600 lin.ft. 3 each 2 3 k 60 1,500 8,800 3 each each each cu.yd. lbs. lin.ft. each 1.00 $.k$ 10.70 U5o.oo lump sum 200.00 300.00 150.00 65.00 0.65 0.60 150.00 11,800 6k, 300 17,100 1,1|00 1,800 !|00 900 600 3,900 1,000 5,300 Uoo $ 88,U( C-52 ESTIMATED COST OF DISTRIBUTION SYSTEM FROM CASITAS RESERVOIR (Continued) Unit price Item Quantity Cost CPITAL COSTS E ldwin Road - Santa Ana Conduit (Continued) "Highway crossing Reservoir Right of way £ nor Canyon Extension "Excavation and backfill Furnish and install 10- inch diameter welded \ steel pipe Gate valves - 6-inch dia. i Line meter Blowoff valves ; Air valves Service outlets j Concrete structures Miscellaneous metal Road surfacing Fire hydrants Pumping plant Right of way jf mada Larga Conduit Excavation and backfill Furnish and install 6- inch diameter welded steel pipe Gate valves - U-inch dia. Line meter Blowoff valves Air valves Service outlets Concrete structures Miscellaneous metal Road surfacing Fire hydrants Highway crossing Pumping plant Right of way .neon Conduit Excavation and backfill Furnish and install welded steel pipe 10-inch diameter 8 -inch diameter Gate valves - 6-inch dia. lump sum lump sum lump sum 29,200 lin.ft. 0.80 C-53 $ 9,000 lin.ft. $ 0.80 7,200 9,000 lin.ft. 2.65 23,900 2 each 300.00 600 lump sum 1,000 2 each 200.00 Uoo 2 each 300.00 600 3 each 150.00 Uoo UO cu.yd. 65.00 2,600 1,000 lbs. 0.65 600 2,000 lin.ft. 0.60 1,200 3 each 150.00 Uoo lump sum 13,700 lump sum 2,500 2,500 35,000 5,00 $ i5i,Uoo 23, Uoo 29,200 lin.ft. 1,80 52,600 U each 170.00 700 lump sum Uoo 3 each 100.00 300 U each 200.00 800 5 each 150.00 800 50 cu.yd. 65.00 3,300 1,000 lbs. 0.65 600 10,000 lin.ft. 0.55 5,500 6 each 150.00 900 lump sum 1,000 lump sum 8,500 lump sum 2,500 99,000 lin.ft. 0.75 7U,200 79,000 lin.ft. 2.75 217,300 20,000 lin.ft. 2.25 U5,ooo 6 each 300.00 1,800 55,100 101,300 ESTIMATED COST OF DISTRIBUTION SYSTEM FROM CASITAS RESERVOIR (Continued) • • • 1 Unit : Item : Quantity : price : Cost CAPITAL COSTS Rincon Conduit (Continued) Line meter lump sum $ 1,000 Blowoff valves 10 each $ 200.00 2,000 Air valves 10 each 300.00 3,000 Service outlets 10 each 150.00 i,5oo Concrete structures 80 cu.yd. 65.00 5,200 Miscellaneous metal 5,000 lbs. 0.65 3,200 Road surfacing 20,000 lin.ft. 0.60 12,000 Fire hydrants 10 each 150.00 1,500 Reservoir lump sum 35,000 Pumping plant lump sum 30,900 Right of way lump sum 5,000 $ 1*38,600 Conduit from Matilija Line to Proposed Reservoir 5,000 Excavation and backfill 5,000 lin.ft. 1.00 Furnish and install 11*- inch diameter concrete cylinder pipe 5,000 lin.ft. 5.U5 27,200 Gate valves - 12 -inch dia. 2 each U5o.oo 900 Blowoff valves 2 each 200.00 1*00 Air valves 3 each 300.00 900 Service outlets 3 each 150.00 1*00 Concrete structures 1*0 cu.yd. 65.00 2,600 Miscellaneous metal 1,000 lbs. 0.65 600 Road surfacing 1*,000 lin.ft. 0.60 2,1*00 Fire hydrants 1* each 150.00 600 Reservoir lump sum 35,ooo Right of way lump sum 5,ooo $2 81,000 Subtotal ,316,700 Administration and engineering, 10$ 3 231,700 Contingencies, 1$% 3ll7,5O0 Interest during construction $2 57,900 TOTAL ,953,800 ANNUAL COSTS Interest, h% $ 118,200 Amortization, l*0-year sinking fund at k% 31,200 Replacement, 30-year sinking fund at 3.5% 9,700 Operation and maintenance lit, 500 Electrical energy 78,1*00 TOTAL $ 252,000 c-5U ESTIMATED COST CF CASITAS - OXNAflD PLAIN DIVERSION (Based on prices prevailing in spring of 1953) Capacity of conduit?. 25> second-feet Length of conduit: 96,300 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, reinforced concrete cylinder, furnish and install, 30-inch diameter 27- inch diameter 115,000 cu.yd 94,800 cu.yd. 49,000 lin.ft. 47,300 lin.ft. Fittings Valves Air release, 3-inch dia. Blowoff, 5-inch dia. Gate, 24- inch dia. - Venturi meter River crossings Road resurfacing and crossings Right of way Subtotal Administration and engineering, 10$ Contingencies, 15% Interest during construction TOTAL 1.29 0.53 10.10 8.93 lump sum $ 148,400 50,200 494,900 422,400 41,800 6 each 6 each 3 each 300.00 1,000.00 1,300.00 1,800 6,000 3,900 1 each 5,000.00 5,000 lump sum 85,000 lump sum 21,000 lump sum 29,800 $1,310,200 $ 131,000 196, 500 32,800 $1,670,500 ANNUAL COSTS Interest., k% Amortization, 20-year sinking fund at k% Operation and Maintenance TOTAL $66,800 56,100 4,200 $127,100 C-55 ESTIMATED COST OF SANTA CLARA RIVER CONDUIT DEVIL CANYON DAM TO SESPE CREEK (Based on prices prevailing in spring of 1953) Capacity of conduit: 65 second-feet Length of conduit: 90,200 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, reinforced concrete, furnish and install U2-inch diameter 36-inch diameter Fittings Valves Air release, U-inch diameter Blowoff, 6-inch diameter Gate, 36-inch diameter Venturi meter River crossings Road resurfacing Right of way Subtotal Administration and engineering, 10$ Contingencies, \$% Interest during construction TOTAL 1U2,000 cu.yd. $ 0.90 $ 127,800 11U,800 cu.yd. 0.1*5 51,700 26,600 lin.ft. 16.19 1;30,700 63,600 lin.ft. 12.13 771,500 lump sum 55,200 7 each 8 each 2 each liOO.OO 1,300.00 3,600.00 2,800 10,1*00 7,200 1 each 5,000.00 5,000 lump sum 65,000 lump sum 35,000 lump sum 16,000 $1,578,300 $ 157,800 236,700 39^00 $2,012,300 ANNUAL COSTS Interest, k% Amortization, 1+0-year sinking fund at U% Operation and maintenance TOTAL $ 80,500 21,200 5,000 $ 106,700 c-56 ESTILiATED COST OF SANTA CLARA RIVLR CONDUIT SANTA FELICIA DAM TO SESPE CREEK (Based on prices prevailing in spring of 1953) '•apacity of conduit: 65 second-feet Length of conduit: 77, 100 lineal feet • • • • Unit : Item : Quantity : price : Cost ■ APITAL COSTS xcavation 129,200 cu.yd. 0.90 Q 116,300 iackfill 103,700 cu.yd. o.U5 1^6,700 ipe, reinforced concrete, furnish and install It2-inch diameter 5U,200 lin.ft. : 36-inch diameter 22,900 lin.ft. 16.02 11.65 868,300 266,800 it tings lump sum 56,800 alves Air release, U-inch dia. Blowoff , 6-inch dia. Gate, 36-inch dia. 7 8 2 each each each liOO.OO 1,300.00 3,600.00 2,800 io,Uoo 7,200 snturi meter 1 each 5,000.00 5,000 Lver crossings lump sum 65,000 Dad resurfacing lump sum 35,000 Lght of way lump sum 16,000 Subtotal #1,1*96,300 ilministration and engineering, 10$ <>ntingencies, V~>% iiterest during construction TOTAL $ lii9,600 22l|,i|00 37,^00 #1,907,700 i!NUAL COSTS i'.terest, h% Ziortization, UO-year sinking fund at h% (eration and maintenance TOTAL $ 76,300 20,100 1^,800 5 101,200 c-57 ESTIMATED COST OF SANTA CLARA RIVER CONDUIT SESPE CREEK TO OXNARD RESERVOIR (Based on prices prevailing in spring of 1953) Capacity of conduit: 120 second-feet Length of conduit: 92,500 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, reinforced concrete, furnish and install 5>lj.-inch diameter U8-inch diameter U2-inch diameter Fittings Valves Air release, U-inch dia. Blow off, 8-inch dia. Gate, U8-inch dia. Venturi meter River crossings Road resurfacing Right of way Subtotal Administration and engineering, Contingencies, V~>% Interest during construction TOTAL 211,000 cu.yd. Z 0.90 159,700 cu.yd. 0.1*5 67,500 lin.ft. 15,000 lin.ft. 10,000 lin.ft. h each 3 each 3 each 1 each 10£ 20.10 16.95 1U.25 lump sum IiOO.00 1,600.00 8,700.00 10,000.00 lump sum lump sum lump sum § 189,900 71,900 1,356,800 25U,300 ll±2,500 81,700 1,600 U,800 26,100 10,000 120,000 10,000 10,600 $2,280,200 $ 228,000 3U2,000 57,000 $2,907,200 ANNUAL COSTS Interest, k% Amortization, UO-year sinking fund at k% Operation and maintenance TOTAL 116,300 30,600 7,300 l$k 9 200 C-58 ESTIMATED COST OF SANTA CLARA RIVER CONDUIT SESPE FEEDER (Based on prices prevailing in spring of 1953) Japacity of conduit: 3>5> second-feet Length of conduit: 28,800 lineal feet • • • Unit Item : Quantity : price : Cost APITAL COSTS iversion -works I Excavation 9,770 cu.yd. % 1*.00 % 39,100 Concrete Weir and cutoff 3,620 cu.yd. 35.00 126,700 Walls 1*90 cu.yd. 50.00 2U,500 Reinforcing steel 109,900 lbs. 0.15 16,500 Trashrack steel 16,700 lbs. 0,20 3,300 Outlet gates lump sum 1*,200 Sand trap lump sum 9,800 % 22l*,100 ipe line Excavation 1*3,200 cu.yd. 0.95 1*1,000 Backfill 35,11*0 cu.yd. 0.1+5 15,800 Pipe, reinforced con- crete, furnish and install, 36-inch dia. 28,600 lin.ft. 11.65 335,500 Fittings lump sum 16,800 Valves, furnish and install Air release, l*-inch dia. 2 each to. 00 800 Blowoff, 8 -inch dia. 2 each 1,500.00 3,000 Gate, 30-inch dia. 2 each 3,000.00 6,000 Meter and junction lump sum 7,500 Road and railroad crossing lump sum 3,000 i Right of way lump sum 8,500 U37,900 Subtotal $662,000 iministration and engineering, 10$ % 66,200 ontingencies, 1$% 99,300 iterest during construction 16,500 TOTAL $81*1*, 000 ..INUAL COSTS iterest, h% aortization, l*0-year sinking fund at deration and maintenance TOTAL $ 33,800 8,900 1*,200 $ 1*6,900 C-59 ESTILIATED COST OF OXNARD PLAIN- PLEASANT VALLEY DISTRIBUTION SYSTEM (Based on prices prevailing in spring of 1953) Capacity of conduit: 120 second-feet Length of conduit: 17l|, 500 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, reinforced concrete, furnish and install Fittings Valves Line meters Service outlets Road and stream crossings Road resurfacing Regulating reservoirs Right of way Subtotal Administration and engineering, 10$ Contingencies, lS% Interest during construction TOTAL 219,000 cu.yd. $ 0.90 $ 197,100 178,UOO cu.yd. 0.1*5 80,300 17u,500 lin.ft. 9.U9 1,656,000 lump sum 82,800 lump sum 35,700 3 each hi 000.00 12,000 191 each 150.00 28,700 lump sum 5,000 lump sum 10,000 lump sum 250,000 lump sum 25,000 $2,382,600 $ 238,300 357,aOO 59,iiOO $3,037,700 ANNUAL COSTS Interest, h% Amortization, IjO-year sinking fund at h% Operation and maintenance TOTAL $ 121,500 32,000 15,200 $ 168,700 C-60 ESTIMATED COST OF OXNARD-PORT HUENEME CONVEYANCE AND PUMPING SYSTEM (Based on prices prevailing in spring of 1953) Capacity of conduit: i|0 second-feet Length of conduit: £0,700 lineal feet i : Unit : Item • • Quantity : price : Cost CAPITAL COSTS Pipe line Excavation 79,hOO cu.yd. $ 0.95 $ 75,1+00 Backfill 65,900 cu.yd. o.U5 29,700 Pipe — furnish and ins stall, reinforced concrete • cylinder H2-inch dia. 18,550 lin.ft. ih.25 26^,300 36-inch dia. Li,25to lin.ft. 11.65 U9,500 30-inch dia. 15,600 lin.ft. 9.30 lii5,100 2ii-inch dia. 12,300 lin.ft. 7.15 87,900 Fittings (elbows, re- ducers, enlargers, etc.) lump sum I5,ii00 Valves — furnish and install Gate 36-inch dia. 1 each 1,800.00 1,800 Gate 30-inch dia. 3 each 1,200.00 3,600 Gate 2li-inch dia. 1 each 800.00 800 Air release 3 each U00.00 1,200 Blowoff 3 each 500.00 1,500 Line meters 2 each 2,900.00 5,800 Road surfacing 9,500 lin.ft. 0.80 7,600 Railroad crossings k each 200.00 800 Right of way lump sum 10,000 $ 700,1*00 Pumping system Well, gravel packed, drilled 16 each 3,750.00 60,000 and cased, 18-inch dia. Pump and motor installed 16 each k, 330. 00 69,300 Pipe — furnish and install reinforced concrete cylinder l|2-inch dia. 1,500 lin.ft. llu25 21,1*00 30-inch dia. 2,880 lin.ft. 9.30 26,800 18-inch dia. 3,220 lin.ft. 5.25 16,900 Valves — furnish and install Gate 18-inch dia. 7 each 600.00 1,200 Check 18 -inch dia. 16 each 300.00 14,800 Land acquisition bO acres 3,000.00 120,000 Fencing 9,600 lin.ft. 1.00 9,600 333,000 Subtotal $1,033,1*00 c-61 ESTIMATED COST OF OXNARD-PORT HUENEME CONVEYANCE AND PUMPING SYSTEM (Continued) Item Quantity Unit price Cost CAPITAL COSTS Administration and engineering, 10$ Contingencies, 13$ Interest during construction TOTAL $ 103,300 155,000 25,800 #1,317,500 ANNUAL COSTS Interest, k% Amortization, UO-year sinking fund at h% Replacement, 30- year sinking fund at 3«5$ Electrical energy Operation and maintenance TOTAL $ 52,700 13,900 1,300 20,U00 6,000 $ 9^,300 I C-62 ESTIMATED COST OF PIRU-LAS POSAS DIVERSION CONDUIT (Based on prices prevailing in spring of 1953) lapacity of conduit: 80 second-feet Length of conduit: 67,500 lineal feet Item • • • • : Quantity : Unit : price : Cost APITAL COSTS xc a vat ion 1 67, 81*0 cu.yd. $ 0.95 $ 159,1*00 ackfill 123,820 cu.yd. 0.1*5 55,700 ipe, lock joint concrete cylinder, furnish and install 60-inch diameter 51*-inch diameter 51*, 800 lin.ft. 12,700 lin.ft. 39.53 32.17 2,166,200 1*08,600 alves Air release, l*-inch dia. Blowoff, 8 -inch dia. Gate, l*2-inch dia. 9 each 9 each 1* each 1*90.00 1,650.00 7,200.00 l*,l*oo 11*, 900 28,800 ittings lump sum 128,700 ine meters lump sum 15,000 tructural concrete 220 cu.yd. 90.00 19,800 iscellaneous metal ll*,600 lbs. 0.55 8,000 oad resurfacing 25,000 lin.ft. 1.55 38,800 iver crossings 700 lin.ft. 1*0.65 28,500 appy Camp Canyon Tunnel 13,500 lin.ft. 165.00 2,227,500 ight of way lump sum 50,000 Subtotal ^5,351*,300 ^ministration and engineering, Dntingencies, ~L$% iterest during construction 10$ $ 535,1*00 803,100 267,700 TOTAL ^6,960,500 \INUAL COSTS iterest, h% aortization, i*0-year sinking fund at h% deration and maintenance $ 278,1*00 73,200 17,1*00 TOTAL $ 369,000 C-63 ESTIMATED COST OF SPREADING WORKS IN EAST LAS POSAS, AND SIMI BASINS (Based on prices prevailing in spring of 1953) j : Unit : Item ; Quantity ; price : Cost CAPITAL COSTS Happy Camp Spreading Works - Capacity 50 second-feet Levees 89*220 cu.yd. 0.35 $ 31,200 Strip checking grounds 50 acres $300.00 15,000 Riprap 1,200 cu.yd. U.00 a, 800 Feeder system to basins 2,600 lin.ft. 7.60 19,800 Stilling wells 3 each 700.00 2,100 Corrugated metal culverts, in place, including • end sections, and toe- plates 15 each 2I0.00 3,600 Right of Way 50 acres 500.00 2^,000 $ 101,50c Happy Camp - Simi Lateral - Capacity 30 second- feet Excavation 96,000 cu.yd. 0.95 91,200 Backfill 67,200 cu.yd. 0.U5 30,200 Pipe — furnish and install U2-inch diameter concrete U8,000 lin.ft. 23.77 i,ila,ooo Valves lump sum 7, loo 1 ,269,80c Dry Canyon Spreading Works - Capacity 30 second -feet Levees 121,200 cu.yd. 0.35 U2,Uoo Strip checking ground 70 acres 300.00 21,000 Stilling well 1 each 700.00 700 Corrugated metal culverts, in place, including end sections, and toe- plates 18 each 2U0.00 U,300 Right of Way 70 acres 2,000.00 iUo,ooo 208,U0( Subtotal n,579,70C Administration and engineering, 10$ $ 158,00( Contingencies, 1$% 237,0a Interest during construction 39,50( TOTAL •$2,OlU,20( ANNUAL COSTS Interest, h% $ 8O,60C Amortization, Uo-year sinking fund at h% 21,20( Operation and maintenance 5,oot. TOTAL $ 106, 80( C-6U ESTIMATED COST OF FILLMORE WELL FIELD (Based on prices prevailing in spring of 1953) !apacity of pumps: ^>S second-feet Iross seasonal pumpage: 22,000 acre-feet • • « • Item : Quantity : Unit : price : Cost iAPITAL COSTS 'ell, gravel packed, drilled and cased, 18 -inch diameter 18 each $3,080.00 $ 55,koo ump, motor and equipment, installed 18 each ii,330.00 77,900 Ipe, welded steel 18-inch diameter 3,600 lin.ft. ; 30-inch diameter 3,800 lin.ft. 5.25 10.10 18,900 38,1*00 alves lump sum 5,000 ence 7,200 lin.ft. 1.00 7,200 egulating reservoir lump sum 20,000 ight of way 30 acres 1,500.00 U5,ooo Subtotal $267,800 dministration and engineering, 10$ ontingencies, 1$% nterest during construction $ 26,800 hO, 200 3,300 TOTAL $338,100 NNUAL COSTS nterest, k% mortization, liO-year sinking fund at k% eplacement, 30-year sinking fund at 3 .5$ lectric energy peration and maintenance TOTAL $ 13,500 3,600 2,600 30,800 5,000 $ 55,500 C-65 ESTIMATED COST OF VENTURA COUNTY AQUEDUCT TO CONNECT WITH FACILITIES OF METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA (Based on prices prevailing in spring of 1953) Capacity of conduit: 25 second-feet Length of conduit: 438,800 lineal feet Item . • Quantity : Unit price : Cost CAPITAL COSTS Excavation 625,100 cu.yd. $ 1.70 $ 1,062,700 Backfill 516,500 cu.yd. O.76 392, 500 Pipe, lock joint concrete cylinder furnish and install, 36-inch diameter 24- inch diameter 18- inch diameter 414,800 lin.ft. 5,000 lin.ft. 3,800 lin.ft. 17.30 8.50 6.50 7,176,000 42,500 24,700 Valves-furnish and install Air release - 3 -inch diameter 49 each Blowoff - 6-inch diameter 46 each Gate 6 each 325.00 1,250.00 2,200.00 15,900 57,500 13,200 Venturi meter and equipment 2 each 18,000.00 36,000 Fittings (Elbows, redu- cers, enlargers, man- holes, passholes, etc.) lump sum Administration and engineering, Contingencies, 15$ Interest during construction TOTAL 334,900 Road surfacing Temporary Permanent 16,600 tons 23,700 tons 4.50 6.00 74,700 142, 200 River crossings Railroad crossings 3,450 lin.ft. 620 lin.ft. 36.70 38.00 126,600 23,600 Santa Susana tunnel 15,200 lin.ft. 165.00 2,508,000 Pumping plant and equipment 2 each 145,500.00 291,000 Right of way lump sum 76,000 Subtotal $12,398,000 $ 1,239,800 1,859,700 929,800 $16,427,300 C-66 ESTIMATED COST OF VENTURA COUNTY AQUEDUCT TO CONNECT WITH FACILITIES OF METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA (Based on prices prevailing in spring of 1953) Capacity of conduit: 50 second-feet. Length of conduit: li38,800 lineal feet. • • Item : • Quantity : Unit : price : Cost CAPITAL COSTS Excavation 883,600 cu.yd. $ 1.70 $ 1,502,100 Backfill 675,200 cu.yd. 0.76 513,200 Pipe, lock joint concrete cylinder, furnish and install, 48-inch diameter 28-inch diameter 24-inch diameter 414,800 lin.ft. 5,000 lin.ft. 3,800 lin.ft. 32.65 9.60 8.50 13,543,200 48,000 32,300 Valves-furnish and install Air release - Zj-inch diameter 49 each Blowoff - 8-inch diameter 46 each Gate 6 each 360.00 1,550.00 6,450.00 17,600 71,300 38,700 Venturi meter and equipment 2 each 18,000.00 36,000 Fittings (Elbows, redu- cers, enlargers, man- holes, pass holes, etc.) lump sum 645,300 Road surfacing Temporary Permanent 30,300 tons 42,400 tons 4.50 6.00 136,400 254,400 River crossings Railroad crossings 3,450 lin.ft. 620 lin.ft. 39.90 58.00 137,700 36,000 Santa Susana tunnel 15,200 lin.ft. 165.00 2,508,000 •Pumping plant and equipment 2 each 244,900.00 489,800 Right of way lump sum 76,000 Subtotal $20,086,000 Administration and engineering, 10$ Contingencies, 15$ Interest during construction $ 2,008,600 3,012,900 1.506,400 TOTAL $26,613,900 C-67 ESTIMATED COST OF VENTURA- COUNTY AQUFDUCT TO CONNECT 1JITH FACILITIES OF T'ETROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA (Based on prices prevailing in spring of 1953) Capacity of conduit: 75 second -feet Length cf conduit: ^38,800 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, lock joint concrete cylinder, furnish nna install, 5^-inch diameter 30 -inch diameter 28 -inch diameter 1,008,900 cu.yd. 763,000 cu.yd. i+lU,800 lin.ft. 5,000 lin.ft , 3,800 lin.ft, I Valves -furnish and install Air release - 5 -inch diameter 1+9 each Blowoff - 10 -inch diameter k6 each Gate 6 each Venturi meter and equipment Fittings (elbows, redu- cers, enlargers, man- holes, passholes, etc.) 2 each 1.70 O.76 38.90 10.10 9.60 U25.OO 1,650.00 6,1+50.00 20,000.00 lump sum $ 1,715,100 579,900 16,135,700 50,500 36,500 20,800 75,900 38,700 U0,000 771,300 Road surfacing Temporary Permanent 30,100 ton U8, 500 ton U.50 6.00 135, J*oo 291,000 River crossings Railroad crossings 3,^50 lin.ft. 620 lin.ft. 67.OO 150,000 kl, 500 Santa Susana tunnel 15,200 lin.ft. 165.OO 2,508,000 Pumping plant and equipment 2 each 331,900.00 663,800 Right of way lump sum 76,000 Subtotal &2^.^no.ioo Administration and engineering, Contingencies, 15$ Interest during construction TOTAL $ 2,333,000 3,^99,500 1,7^9, 800 $30,912,1+00 C-68 ESTIMATED COST OF VENTURA COUNTY AQUEDUCT • TO CONNECT .WITH FACILITIES OF 'METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA (Based on prices prevailing in spring of 1953) Capacity of conduit: 100 second-feet Length of conduit: 438,800 lineal feet Item Quantity Unit price Cost CAPITAL COSTS Excavation Backfill Pipe, lock joint concrete cylinder, furnish and install, 60 -inch diameter 36 -inch diameter 30-inch diameter 1,151,200 cu.yd. 851,000 cu.yd. 414,800 lin.ft. 5,000 lin.ft. 3,800 lin.ft. $ 1.70 O.76 45.60 13.00 10.10 Valves -furnish and install Air release - 5-inch diameter 49 each Blowoff - 10-inch diameter 46 each Gate 6 each Venturi meter and equipment Fittings (elbows, redu- cers, enlargers, man- holes, passholes, etc.) 2 each 425-00 1,650.00 14,680.00 27,000.00 lump sum $ 1,957,000 646,800 18, 914, 900 65,000 38,400 20,800 75,900 88, 100 54,000 906,800 Road surfacing Temporary Permanent 37,000 54,250 ton ton 4.50 6.00 166, 500 325,500 River crossings Railroad crossings 3,450 620 lin.ft. lin.ft. 47.ll 75.00 162, 500 46, 500 Santa Susana tunnel 15,200 lin.ft. I65.OO 2,508,000 Pumping plant and equipment 2 each 411,600.00 823,200 Right of way lump sum 76,000 ;.; Subtotal $26,875,900 Administration and engineering, 10$ Contingencies, 1% Interest during construction $ 2,687,600 4,031,400 2,015,700 TOTAL $35,610,600 C-69 ESTIMATED COST OF VENTURA COUNTY AQUEDUCT TO CONNECT WITH FACILITIES OF METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA (Based on prices prevailing in spring of 1953) Capacity of conduit: 150 second-feet Length of conduit: 1*38,800 lineal feet : "1 Unit : Item : Quantity : price : Cost CAPITAL COSTS Excavation Backfill Pipe, lock joint concrete cylinder, furnish and install 7 2- inch diameter 1*2- inch diameter 3 6- inch diameter Valves-furnish and install Air release - 6- inch dia. Blowoff - 12 -inch dia. Gate Venturi meter and equipment Fittings (elbows, reducers, enlargers, manholes, pass- holes, etc.) lump sum 1,200,1*00 Road surfacing Temporary Permanent River crossings Railroad crossings Santa Susana tunnel Pumping plant and equipment Right of way Subtotal $3k, 3^7,500 Administration and engineering, 10$ $ 3,l*3i*,800 Contingencies, \% 5,152,100 Interest during construction 3, l*3l*, 800 TOTAL $1*6,369,200 1,1*61*, 300 cu.yd. $ 1.70 $ 2,1*89,300 1,035,000 cu.yd. 0.76 786,600 l*ll*,800 lin.ft. 5,000 lin.ft. 3,800 lin.ft. 60.1*0 21.10 13.00 25,053,900 105,500 1*9,1*00 1*9 each 1*6 each 6 each 1*90.00 1,750.00 ll*,680.00 2l*,000 80,500 88,100 2 each 27,000.00 51*, ooo 1*1*, 300 tons 66,1*00 tons U.50 6.00 199,1*00 398,1*00 3,li50 lin.ft. 620 lin.ft. 50.70 90.00 171*, 900 55,800 15,200 lin.ft. 165.00 2,508,000 2 each 501,650.00 1,003,300 lump sum 76,000 C-70 ESTIMATED COST OF OAK CANYON LATERAL (Based on prices prevailing in the spring of 1953) Capacity of conduit : 40 second- -feet Length of conduit: 4,010 lineal feet • • Item : Quantity : Unit : price - • • : Cost ' CAPITAL COSTS Excavation 7,100 cu.yd. $ 0.90 $ 6,400 Backfill 5,700 cu.yd. 0.45 2,600 Pipe, lock joint concrete cylinder, furnish and install, 42- inch diameter 4,010 lin.ft. 22.30 89,400 Valves - furnish and install Air release, 4-inch diameter Blowoff, 8-inch diameter Gate, 36-inch diameter 2 each 2 each 1 each 350.00 1,550.00 6,500.00 700 3,100 6,500 Fittings (elbows, reducers, enlargers, etc.) lump sum 9,200 Right of way lump sum 4,000 Pumping plant and equipment . lump sum 38,500 Subtotal $160,400 Administration and engineering, Contingencies, 15$ lOg $ 16,000 24,100 Interest during construction, none TOTAL $200, 5^0 C-71 ESTIMATED COST OF OAK CANYON DAM AND RESERVOIR WITH STORAGE CAPACITY OF 7,500 ACRE-FEET (Based on prices prevailing in spring of 1953) Elevation of crest of dam: 1,110 feet Elevation of crest of spillway: 1,100 feet Height of dam to spillway crest, above stream bed: 170 feet Capacity of reservoir to crest of spillway: 7,500 acre-feet Capacity of spillway with 5-foot freeboard: 2,000 second-feet • • • • Unit : Item : Quantity : price : Cost CAPITAL COSTS Dam Exploration lump sum $ 10,000 Diversion of stream and dewatering of foundation lump sum 1,000 Stripping topsoil 25,000 cu.yd. $ 0.60 15,000 Foundation excavation Abutment 22,000 cu.yd. 1.50 33,000 Channel 91,000 cu.yd. 0.60 51i, 600 Embankment Impervious 586,1*00 cu.yd. 0.65 381,200 Random 1 ,000,300 cu.yd. 0.55 550,200 Rock riprap 39,1*00 cu.yd. U.00 157,600 Drilling grout holes 6,1+00 lin.ft. 3.00 19,200 Pressure grouting 1*,200 cu.ft. U.00 16,800 $L, 238, 600 Spillxvay • Excavation 900 cu.yd. 1.50 i,l*oo Concrete Weir and cutoff 230 cu.yd. 35.00 8,000 Floor 1*20 cu.yd. 30.00 12,600 Walls U20 cu.yd. I4O.00 16,800 Reinforcing steel 75,600 lbs. 0.15 11,300 50,100 Outlet Works Tower concrete 580 cu.yd. 80.00 1*6,1*00 Concrete encasement 1470 cu.yd. 1*0.00 18,800 Steel pipe, U8-inch dia. 1,020 lin.ft. 25.00 25,500 Tower inlet valve, 30- inch dia. h each 3,000.00 12,000 Needle valve, U2-inch dia. JL each 12,000.00 12,000 Miscellaneous metal work 17,500 lbs. 0.1*0 7,000 121,700 Reservoir Land acquisition lump sum 1*8,000 Clearing 160 acres 10.00 1,600 1*9,600 Subtotal &L, 1*60,000 Administration and engineering, 10$ $ 11*6,000 . Contingencies, ]£% 219,000 Interest during construction 36,000 TOTAL $1,861,000 : c-72 ESTIMATED COST OF CONE JO DM AND RESERVOIR WITH STORAGE CAPACITY OF 20,000 ACRE-FEET (Based on prices prevailing in spring of 1953) Levation of crest of dam: 375 feet ILevation of crest of spillway: 360 feet bight of dam to spillway crest, above stream bed: 130 feet Capacity of reservoir to crest of spillway: 20,000 acre-feet Capacity of spillway with 5-foot freeboard: 6,000 second- feet • • • Unit : Item : Quant: -ty : price : Cost CiPITAL COSTS lam Exploration lump sum $ 20,000 Diversion of stream and dewatering of foundation lump sum 10,000 Stripping topsoil l*5,ooo cu.yd. I 0.60 27,000 Foundation excavation Abutment 97,000 cu.yd. 1.50 ih5,5oo Channel Uoo,Uoo cu.yd. 0.60 21*0,200 Embankment Impervious 826,190 cu.yd. 0.70 578,300 Random 628,820 cu.yd. 0.60 1*97,300 Rock riprap 28,800 cu.yd. IwOO 115,200 Drilling grout holes 11,900 lin.ft. 3.00 35,700 Pressure grouting 7,900 cu.ft. 1*.00 31,600 $1,700,800 ipillway Excavation 120,000 cu.yd. 2.00 21*0,000 Concrete Weir and cutoff 230 cu.yd. 35.00 8,100 Floor 700 cu.yd. 30.00 21,000 Walls 1,000 cu.yd. 1*0.00 1*0,000 Reinforcing steel 153,000 lbs. 0.15 23,000 332,100 utlet Works Tower concrete 500 cu.yd. 80.00 1*0,000 Concrete encasement 600 cu.yd. 1*0.00 21*, 000 Steel pipe 72-inch dia. 800 lin.ft. 1*5. oo 36,000 Tower inlet valve 36- inch dia. k each 5,000.00 20,000 Needle valve 60-inch dia. 1 each 27,500.00 27,500 Miscellaneous metal work 35,ooo lbs. 0.U0 lit, 000 161,500 eservoir Land acquisition lump sum 70,000 Clearing 35o acres 50.00 17,500 87,500 Subtotal $2,281,900 dministration and engineering, 10$ $ 228,200 ontingencies, 15$ 31*2,300 nterest during construction 111* ,000 TOTAL $2,966,1*00 C-73 ESTIMATED COSTS OF DISTRIBUTION SYSTEM FOR COLORADO RIVER WATER IN CALLEGUAS-CONEJO HYDROLOGIC UNIT (Based on prices prevailing in spring of 1953) s : Unit : Item : Quantity : price : Cost CAPITAL COSTS Simi-Las Posas Feeder - - Capacity: 65 sec ond-feet Excavation 26,300 cu.yd. $ 0.90 tf 23,700 Backfill 20,000 cu.yd. O.fe 9,000 Pipe, furnish and install reinforced concrete 12, £00 lin.ft. 2U.50 306,300 Fittings lump sum 11;, 500 Valves lump sum 11,200 Line meters lump sum 6,000 Road resurfacing 800 tons 7.50 6,000 Right of way lump sum U,000 $ 380,700 Simi Lateral - Capacity: 15 second-feet Excavation 33,800 cu.yd. 0.90 30,li00 Backfill 29,200 cu.yd. o.U5 13,100 Pipe, furnish and install reinforced concrete 27,000 lin.ft. 9.69 261,600 Fittings lump sum 11,900 Valves lump sum 2,200 Line meters lump sum 2,000 Road crossings lump sum 2,000 Road resurfacing U30 tons 7.50 3,200 Regulating reservoir lump sum 38,300 361i,700 Las Posas Lateral - Capacity: 50 seco nd-feet Excavation 13U,100 cu.yd. 0.90 120,700 Backfill 110,500 cu.yd. 0.U5 U9,700 Pipe, furnish and install reinforced concrete 97,200 lin.ft. 16.29 1,583,300 Fittings lump sum 11*7,200 Valves lump sum U7,900 Line meters lump sum 5,000 Road crossing lump sum 22,000 Road resurfacing 2,100 tons 7.50 15,700 Regulating reservoir lump sum 80,000 Right of way lump sum 2u,000 2 ,095,500 Cone jo Feeder - Capacity: 30 seco nd-feet Excavation 25,100 cu.yd. 0.90 22,600 Backfill 20,900 cu.yd. o.h$ 9, to Pipe, furnish and install reinforced concrete 17,200 lin.ft. 12. U8 211;, 600 Fittings lump sum 13,000 Valves lump sum 13,1*00 Line meters lump sum U,000 Road crossings lump sum 1,000 Road resurfacing 370 tons 7.50 2,800 Regulating reservoir lump sum 70,000 Right of way lump sum 10,300 361,100 C-7U ESTIMATED COSTS OF DISTRIBUTION SYSTEM FOR COLORADO RIVER WATER IN CALLEGUAS-CONEJO HYDROLOGIC ' UNIT (Continued) • : Unit : Item : Quantity : price : Cost APITAL COSTS housand Oaks Lateral - - Capacity: 10 sec :ond-feet Excavation 18,100 cu.yd. :} 0.90 16,300 Backfill 16,200 cu.yd. o.ii5 7,300 ; Pipe, furnish and install reinforced concrete 19,U0O lin.ft. 7.81* 152,100 Fittings lump sum 9,600 Valves lump sum 2,500 Line meters lump sum 2,000 Road crossings lump sum i,5oo 1 Road resurfacing 80 tons 7.50 600 Regulating reservoir lump sum 38,300 Right of way lump sum lU,900 $ 2U5,ioo ewbury Park Lateral - - Capacity: 15 second-feet Excavation 214,700 cu.yd. 0.90 22,200 Backfill 21,900 cu.yd. o'JiS 9,900 i Pipe, furnish and install reinforced concrete 31,900 lin.ft. 6.32 201,600 Fittings lump sum 12,800 . Valves lump sum lt,U00 Line meters lump sum 2,000 Road crossings lump sum 700 ' Road resurfacing • 5U0 tons 7.50 U,100 Regulating reservoir lump sum lilt, 000 Right of way lump sum 15,700 317,1400 Subtotal $3 ,76^,500 dministration and engineering, 10$ $ 376,1+00 ontingencies, 1$% nterest during construction TOTAL 56i+,700 9)4,100 ^,799,700 NNUAL COSTS nterest, h% nortization, U0-year sinking fund at peration and maintenance TOTAL $192,000 50,500 iU,Uoo $256,900 C-75 ESTIMATED COST OF CONDUIT TO DELIVER COLORADO RIVER jATER FROM CONE JO RESERVOIR TO OXNARD REGULATING RESERVOIR AND THE CITY OF VENTURA (Based on prices prevailing in spring of 1953) Item Quantity Unit price Cost CAPITAL COSTS Excavation 227,200 cu.yd. 0.90 $ 20U,500 Backfill 16U,900 cu.yd. o.U5 7l|,200 Pipe, furnish and install 66-inch dia. lock joint concrete cylinder 73,200 lin.ft. Wi.70 3,272,000 Fittings lump sum 163,600 Valves lump sum 13,000 Line meter 1 each 5,000.00 5,000 River crossing lump sum 10,000 Road resurfacing 12,000 tons 6.00 72,000 Right of way lump sum 5,000 03,819,300 Oxnard Reservoir to City of Ventura - • capacity 25 second- "feet Excavation 55,500 cu.yd. 1.05 58,300 Backfill U6,300 cu.yd. 0.55 25,500 Pipe, furnish and install 36-inch dia. lock joint concrete cylinder 37,000 lin.ft. 13.00 I4.8 1,000 Fittings lump sum 214,100 Valves lump sura 8,100 Line meter 1 each 2,000.00 2,000 River crossing 2,200 lin.ft. 35.00 77,000 Road resurfacing 8,000 tons 6.00 1*8,000 Terminal reservoir lump sum Wi,000 Right of way lump sum 15,000 783,000 Subtotal $1^,602,300 Administration and engineering, 10$ 1*60,200 Contingencies, V~>% 690,300 Interest during construction 115,100 TOTAL • #5,867,900 ANNUAL COSTS Interest, h% * 23l»,7°0 . Amortization, l|0-year sinking fund at k% Operation and maintenance 61,700 1U,500 TOTAL $ 310,900 C-76 APPENDIX D SOME ORGANIZATIONAL AND FINANCIAL ASPECTS INVOLVED IN IMPLEMENTING WATER PLANS IN VENTURA COUNTY TABLE OF CONTENTS SOME ORGANIZATIONAL AND FINANCIAL ASPECTS INVOLVED IN IMPLEMENTING WATER PLANS IN VENTURA COUNTY Page Introduction D-l Existing Organized Public Water Districts D-2 Ventura County Flood Control District D-2 Water Conservation Districts D-3 County Water Districts D-5 County Waterworks Districts . D-5 Municipal Water Districts D-6 Other Public and Private Water Agencies D-7 Adequacy of Existing Water Districts as Regards Solution of County Water Problems » D-8 Suggested County-wide Type of Water District to Carry Out Water Development Plans, and Possible Methods of Financing Such Plans . . D-10 SOME ORGANIZATIONAL AND FINANCIAL ASPECTS INVOLVED IN IMPLEMENTING WATER PLANS IN VENTURA COUNTY INTRODUCTION Future economic expansion in Ventura County is believed to be inex- tricably involved with the development of its water resources, together with the furnishing of supplemental supplies and the importation of water from outside the County. In a number of areas throughout the County, utilization of the local water supply is nearly complete, and in some areas the water supply as presently developed is used beyond its safe limits. In these latter instances, the security of investments made many years ago, as well as of those recently made, is becoming increasingly jeopardized. Possibilities for sound future economic growth within the County appear to be remote under present water supply conditions . The physiography of Ventura County, and the location and type of min- eral, agricultural, and other resources therein, present challenges to the people of the County with respect to planning for future economic growth, in- cluding planning to provide utility services for such growth. How the people respond to these challenges will determine the economic course of the future. Because of the unique physiography, the climatic characteristics, and the concentrations of population which bear little relation with concentra- tions of assessed valuation of taxable property, the matter of initiating water resources development plans for Ventura County appears to require some- what unusual approaches with respect to organizational and financial aspects. The objectives of this appendix report are: (1) a general review of the pur- poses and powers of existing organized public water districts in Ventura County; (2) discussion of the adequacy of existing water districts with regard to solution of the County's water problems; and (3) suggestion of a county-wide D-l type of water district which would plan, finance, construct, and operate water resources projects. EXISTING ORGANIZED PUBLIC WATER DISTRICTS In California there are so many kinds of water districts that may be organized by local interests, each kind of which is designed to meet a special circumstance or need, that it behooves local interests to be certain that they either have, or organize, a type of district that best fits their overall needs. The Legislature has enacted more than 30 general and more than 30 special water district acts for the primary purpose of assisting local interests to resolve their local water problems. Investigation of Ventura County and its water problems indicates that there are several factors that should be considered in ascertaining what . type of public water district is desirable, and whether the existing district . are satisfactory to cope with the problems at hand. These factors include th following: the purposes and powers of the district, the basis of voting, the . type of governing board, restrictions on and kinds of indebtedness that may- be incurred, and the legally available sources of revenue that may be obtaine and used to retire such indebtedness. These matters will be considered in describing the existing districts, and in suggesting what types of districts may be desirable for Ventura County. Ventura County Flood Control District This district was organized in 1944, under the provisions of a special enabling act passed by the Legislature, known as the "Ventura County Flood Control Act" . It is the only district that embraces the entire County Its purposes and powers were appreciably broadened by passage of Assembly Bi3 No. 494 by the Legislature in 1953. Among other things, the District may D-2 control flood and storm waters, store, spread and sink water, reclaim water, import water, sell water, and levy charges for the use of ground water in areas where the District spreads water. The District is divided into four zones to accomplish these objectives, and for bonding and assessment purposes. The basis of voting is the qualified registered voter. Thus, tenant and landlord have equal voting power. The Ventura County Board of Supervisors constitutes the governing board of the District. General obligation bonds only may be issued and shall be a lien upon all, but only on the taxable property of the zone of issuance, not the entire District. Said bonds are declared by law to be legal investments and shall be paid from assessments levied within the zone, or out of any other fund of the zone. A two-thirds favorable vote by the electorate in the zone affected is necessary to approve a bond issue. No zone, nor the property therein, shall be liable for the bonded indebtedness of any other zone. Ad valorem taxes may be levied upon all taxable property in the District to pay district costs that are of common benefit to the whole District. The Ventura County Flood Control District does not have specific powers to develop and sell hydroelectric power, issue general obligation bonds which would be a lien upon the entire District, and issue revenue bonds. Water Conservation Districts There are four water conservation districts in Ventura County, namely: San Antonio, Santa Clara, Simi Valley, and United. These districts have been formed under two general enabling acts. The earliest known district of this type formed in the County is the Santa Clara Water Conservation District, which was organized in 1927 under the "Water Conservation Act of 1927". Its powers and purposes are somewhat limited in that there are no provisions with respect to the issuance and sale D-3 of bonds, and its assessment powers are limited. However, within the fore- going severe financial restrictions, the District may acquire, store, and distribute surface water supplies for irrigation, seasonal storage or under- ground replenishment; construct, operate, and maintain works; sell water supplies for surface irrigation; and provide flood protection facilities. The basis of voting is one vote per acre or fraction thereof. There are only a few districts in the State organized under this particular act. The Santa Clara Water Conservation District held an election in 1953 to dissolve the district. However, the proposition failed to carry. In 1929, an alternative law was enacted by the Legislature. In 1931 it was modified and is now known as the "Water Conservation Act of 1931" . It is under these latter two acts that the remaining Ventura County water conser- vation districts were organized. The purposes and powers of districts organ- ized under the 1931 act are somewhat broader in scope and generally more adequate than those organized under the 1927 act. Such districts may not generate and sell hydro-power but may, among other things, conserve and store water by almost any manner of means for- any useful purpose, including the sinking in wells and spreading of water; install and operate wells, pumps, etc.; and sell, deliver, and otherwise dispose of water. Members of the boards of directors are elected by the resident registered voters of the districts. General obligation bonds, approved by a two-thirds vote, may be issued. No revenue bonds are authorized. Ad valorem assessments may be levied on lands or real property, whichever is preferred. Improvement districts may be organized. In addition to the foregoing powers, the Legislature of 1953 grantee the United Water Conservation District special powers to own and operate hydr< electric power facilities in conjunction with its water conservation projects and to sell electrical energy at wholesale at the point of generation. D-4 County Water Districts This type of district is one of the most popular in California, although there is only one in Ventura County - the Meiners Oaks County Water District. The county water district has broad powers. It can, among other things, furnish water for any beneficial use, store and conserve water, generate and sell hydroelectric power, salvage water, sell or lease oil or mineral rights, and cooperate with other entities. The resident registered voter is eligible to vote, and the five-man board of directors is elected from the eligible electorate. Improvement districts may be created to finance projects that are not of benefit to the district as a whole. The district may issue general obligation and revenue bonds . A two-thirds favorable vote of the electorate is required for approval of all bond issues. Revenue may be obtained from sales or leases of facilities and services, including water. Assessments are based upon an ad valorem levy on all taxable property in the district. However, bond assessments may be levied only on those properties so benefited by the bond issue. This type of district is often desirable when water facilities for both urban and rural uses are involved. C ounty Waterworks Districts There are seven districts of this type in Ventura County, as follows: County Waterworks Districts No. l(Moorpark), No. 2 (Heuneme), No. 3 (Simi), No. 4 (Casitas Springs), No. 5 (Camarillo), No. 6 (Thousand Oaks), and No. 7 (Live Oaks Acres). County waterworks districts organized under the enabling act have defined purposes and powers that are more circumscribed than those of a county water district or a water conservation district. Overlapping of boundaries of D-5 certain other types of districts is prohibited. Resident registered voters may vote, and the county board of supervisors is the governing board of the district. The board may appoint directors from among the registered voters who are also owners of real property within the district. General obligation and revenue bonds may be issued, subject to a majority approved vote by the electorate. Special zones or improvement dis- tricts may be formed to construct and finance facilities, or to fix special rates and charges. The district can obtain revenue from the sale of water, and from leases or sales of property. Ad valorem assessments may be levied upon all taxable property. Municipal Water Districts The Ventura River Municipal Water District, formed in 1952, is the only one of this type in Ventura County. Residents of the Calleguas Creek watershed area will soon vote on forming the Calleguas Municipal Water Distri This type of district has broad purposes and powers and may, among other things, acquire water works, water rights, store and distribute water, sell water to all public and private entities and to individuals, salvage water, and spread and purify water. However, it may not develop hydroelectri power potentialities, nor carry on flood control activities. The area of the district may include both incorporated and unincor- porated territory. Resident registered voters may vote. Members of the boar of directors are elected by qualified voters in the district. Improvement districts may be formed for certain special purposes which do not equally affect the district as a whole. General obligation bonds only may be issued, subject to approval by a two-thirds vote, and are declared by law to be legal investments. Revenue may accrue from a number of sources. Ad valorem assess ments may be levied upon all taxable property. D-6 Other Public and Private Water Agencies In addition to the foregoing public water districts in Ventura County, there are four soil conservation districts, two of which lie wholly within the County, nine privately owned public water service utilities, and more than ninety mutual water companies. Soil conservation districts exist for the principal purposes of control of runoff, prevention and control of soil erosion, improvement of farm irrigation, development of farm storage and distribution of water, and land drainage. Although the purposes of such districts are commendable, their limited financing capacity, together with the nature and characteris- tics of their projects, precludes further consideration of soil conservation districts for purposes of implementing the water development program outlined in this bulletin. The privately owned public utility is operated for profit, and sells a service subject to the regulations of the State Public Utilities Commission. Because it must operate for profit purposes, and because venture capital flows to t hose areas and activities in which either the risks are less or the net returns are more than those accruing from financing water supply facilities, this type of public utility in recent years has not been able to resolve complex water problems. The number of privately owned water utilities is dwindling as public water districts are formed for the purpose of acquiring private properties and operating them. It is not a so-called community type of organization. The mutual water company is a community organization which may be incorporated or unincorporated. It is a voluntary nonprofit enterprise, primarily engaged in supplying water to its stockholding members. Like the foregoing commercial utility, it has no power of taxation. The mutual water company is controlled by its members rather than by the qualified electors. D-7 It is not required to serve water to nonmembers, and no pne is compelled to join it. Only where water problems are not complex, water users are rela- tively few in number, and simplicity and ease of formation and operation are desired and possible, does this type of organization appear to be suitable. ADEQUACY OF EXISTING WATER DISTRICTS AS REGARDS SOLUTION OF COUNTY WATER PROBLEMS Existing institutional factors in Ventura County are deemed to be inadequate for the purpose of implementing a plan of comprehensive county-wid water development. The existing districts, with their present limited power, jurisdictional areas, and tax bases, are not equipped to finance, construct, or operate water resource development works of the magnitude required to solv the water problems of Ventura County. Neither are they adequate to facilitat the equitable distribution of necessary supplemental water to areas of need. In spite of the number of public water districts that now exist in Ventura County, relatively little has been accomplished in the aggregate to- ward resolving the County's water problems. Annual sums disbursed by the County and special districts for water amount to only about one per cent of the aggregate sum disbursed for all activities. The Santa Clara Water Consei vation District has been spreading runoff waters for a number of years, an activity recently taken over by the United Water Conservation District. Zonel of the Ventura County Flood Control District has constructed and operates the Matilija Dam and Reservoir. The United Water Conservation District is under taking a $10,900,000 program on Piru Creek with the objective of resolving it water problems. However, these steps, though pointed in the right direction are only a small beginning of what could and should be accomplished. The Ventura River Municipal Water District appears to be the only district with sufficient present financial capacity to develop supplemental water supplies to fully satisfy present water supply deficiencies within the D-8 district boundaries. In the case of this District, under the most feasible plan for development of the Ventura River watershed, a relatively large surplus of water over and above present requirements within the district boundaries would be developed. An immediate market for this surplus is available in the coastal plain of the Santa Clara River Valley outside the limits of the Dis- trict. However, desirable interim use of this surplus supplemental water supply in the Oxnard Plain and Pleasant Valley Subunits would be facilitated if the export were under the jurisdiction of a district with broader powers and areal jurisdiction than the Ventura River Municipal Water District. Such interim export and sale of the surplus water could ease the financial burden of taxpayers and water users in said District. Existing water districts do not appear to be either financially capable or equipped with sufficient legal powers to effect the indicated desirable diversion of surplus waters in Piru Creek for use in the water- deficient Calleguas-Conejo Hydrologic Unit. Under the plan recommended in this bulletin, sufficient water could be diverted and regulated for use in ground water storage in the Calleguas-Conejo Hydrologic Unit to alleviate present water shortages therein, and to provide for some future expansion. Such diversion appears to be the only immediate feasible source of supple- mental water for this area. Based upon the following observations: The generally increasing seriousness of the ground water overdraft in Ventura County; the difficulty that existing districts have experienced in implementing development plans; and the tendency of local interests to be divisive with respect to water resources development, a factor which is aggravated by the zonal type of organ- ization of the Ventura County Flood Control District; and in realization of the fact that imported water will be needed to supplement local supplies; and that full development of the water resources of the several watersheds, D-9 within the limits of engineering and economic feasibility, will enable trans fer of surplus water from one watershed to another; it is believed that the day of independent, uncoordinated, piecemeal planning and implementation of water supply facilities is past, and that an adequate agency is needed now t< accomplish what has not been accomplished to date. SUGGESTED COUNTY-WIDE TYPE OF WATER DISTRICT TO CARRY OUT WATER DEVELOPMENT PUNS, AND POSSIBLE METHODS OF FINANCING SUCH PLANS It is believed that implementation of comprehensive water plans foj Ventura County, as set forth in this bulletin, requires the coexistence of a county-wide water district and a number of smaller supporting water district* hereinafter referred to as member units. There are presently about 20 count} wide water districts in California, of which about one-third are flood contrc districts such as the one in Ventura County. Most of the remaining two-thirc are so-called flood control and water conservation districts. As water supp] problems become increasingly complex and involved due to fluctuating precipit tion and fast growing demands for water, it is believed that county-wide dis- tricts may well assume increasing importance in resolving future water proble of California. The county-wide water district concept is being adopted on a rapidly increasing scale as a natural extension of the local district type in coping with problems of increasing magnitude and number. In one county, the thinking has advanced on water matters to the point that the county governmen contributes $100,000 annually to the county-wide water district, to be used t help defray water costs of several member districts which purchase water unde . long-term contracts from the larger district. In another county, the county- wide water district is proposing to sell irrigation water at below cost to on of its member units, with the loss in revenue estimated at $150,000 to $200,0) per year, to be recouped by means of levying a tax on all of the taxable property of the county. D-10 Principal functions of the county-wide water district proposed for Ventura County, in addition to those already granted by the Ventura County Flood Control District Act as amended, would be facilitating the financing of projects, the construction and probable operation and maintenance of such pro- jects, and the execution of water service contracts with member units. In order to carry out these purposes, it is recommended that additional authority would have to be granted to the district by the Legislature, such as permitting the county-wide district to issue bonds, the proceeds from the sale of which would be used for constructing water development projects, which would consti- tute a lien upon all of the taxable property in the entire County, even though the proceeds thereof might be used to benefit a smaller area. However, it is further recommended that the direct beneficiaries of the project, acting through some subordinate organization, would, concurrent with the issuance of the bonds, execute water service contracts with the county-wide district, with the rates for water being set at a price that over a period of years would pay for operation and maintenance costs, replacement costs, and bond service charges. The foregoing discussion assumes that general obligation bonds would be issued. An alternative to this means of raising funds for construction would be the issuance of revenue bonds. The holder of such bonds would prob- ably have first claim to all project revenues. In calling for bids for such bonds the district would probably require a minimum bid of par, with the interest rate or rates to be fixed by the bidder. In determining whether to bid at all or what interest rate to specify, groups or syndicates of invest- ment bankers would take into consideration primarily the extent to which estimated net revenues were in excess of bond service requirements. Depending on the extent to which net revenues could be predicted with certainty, based on firm contracts or commitments for water service, they would be expected to equal at least 1.2 times bond service, with the requirements being probably D-ll 1.4 times bond service charges if such revenue estimates were less certain. However at the present time, the Ventura County Flood Control District cannot issue revenue bonds. From the foregoing, it is believed that the particular local area using project water would not be required to raise large funds in advance, and would not necessarily need to hire a staff of qualified personnel to operate and maintain the project. Instead, the county-wide agency could per- form such services. The county-wide agency would probably have less difficul in raising funds through sale of bonds because the entire County's taxing pow would support the bonds, and because of the contracts it would have with sub- ordinate districts for the sale of water, a portion of the revenues from whic would be used to pay off bond service charges. Thus, the county-wide distric might be able to obtain more favorable interest rates and other more favorab] bond issuance features than could the member units. Furthermore, the county- wide district could and should act as arbiter in disputes over water matters between member units. It should also determine that any surplus waters creat by a project would be utilized in adjacent water-deficient areas within the scope of economic limitations. Ventura Gounty is in the upper quarter of counties in California wj respect to assessed valuations. Such values have increased at an impressive rate over a period of several decades. For instance, in the fiscal year 1909-10 the total assessed valuation was $22,189,000; in 1919-20, $38,264, OCX' in 1929-30, $106,620,000; in 1939-40, $96,513,000; and in 1949-50, $228,724,( In the fiscal year 1953-54, the total amounted to $300,966,000. Inflation during the past dozen years accounts for a portion of ,th< foregoing almost phenomenal recent increases in assessed valuations. Howeve: the principal increase may be attributed to growth in population and increas< in output of goods and services in Ventura County. For instance, the populat D-12 of Ventura County increased from IS, 347 in 1910 to 69,685 in 1940, and to 114,647 in 1950. The State Department of Finance estimates that as of July 1, 1953, the population was 133,100, almost double that of 1940. Petroleum production increased from 17,038,470 barrels in 1940, valued at $18,525,000, to almost 34,000,000 barrels in 1950, valued at $92,550,000. Gross farm income (F.O.B. value) increased from $22,600,000 in 1940 to $75,300,000 in 1952. Total public bonded indebtedness in Ventura County as of June 30, 1953, was $15,660,000, including school bonds of $11,221,200, and flood control (Zone 1), county water district, and county waterworks districts bonds in the amount of $3,083,000. In addition to this total, there were more than $3,000,000 in bonds, including self-supporting bonds, issued by the munici- palities of Ventura, Santa Paula, Oxnard Ojai, and Port Heuneme. Excluding the municipal issues, the ratio of about five per cent of outstanding bonded indebtedness to total assessed valuation is below the reported average for all counties of the State. However, unlike that for Ventura County, such ratios calculated for many other counties in the State are misleading inasmuch as they do not include, for example, irrigation district bonds. It is recommended in this bulletin that a plan of water resources development in Ventura County be adopted, including construction of Casitas Dam and Reservoir with a storage capacity of 130,000 acre-feet, Devil Canyon Dam and Reservoir with a storage capacity of 150,000 acre-feet, a well field in Fillmore Basin, and certain distribution and conveyance facilities, at an estimated capital cost of about $52,000,000. The over-all average annual cost of about 73,000 acre-feet of new water developed by the plan would be $40 per ei acre-foot, with average annual unit costs varying from $62 in the Ventura i Hydrologic Unit to $33 in the Santa Clara River Hydrologic Unit. The bulletin further recommends that, if financial capacity does not permit immediate D-13 construction of all features of the plan, a staged development be undertaken whereby construction of those features relating to the proposed diversion to the Calleguas-Conejo Hydrologic Unit be postponed. The estimated capital cos of the initial works under such staged development would be about $43 3 000,00C Pursuant to the act creating the Ventura County Flood Control Dis- trict, bonds (general obligation) issued by the District, which are issued fc any zone thereof, shall be legal investments for all trust funds and for the funds of banks, insurance companies, and for other related types of funds. However, this arbitrary declaration of what constitutes a legal investment ma not, on occasions, mean much to the prospective bidder for such bonds unless certain other criteria have been met. One of the foregoing criteria may be whether the proposed issue meets the requirements of the State Financial Code regarding legal investment Section 1356(g) of that Code states that: "... the net direct debt of such public corporation or of such special district together with its net overlapping debt does not exceed 20 per cent of the assessed valuation of the taxable prop- erty within its boundaries . . .". In some instances, public district bonds have been sold in which th foregoing 20 per cent limitation has been exceeded. However, under such cond tions bond salability oftentimes is made more difficult inasmuch as the numbe of eligible buyers is reduced, and the interest rate must then be increased, or some other concession made, to enhance the salability. A second possible criterion that may be requested by the prospectiv bond purchaser is that such bonds be certified by the California Districts Securities Commission as legal securities, pursuant to Section 20045 of the State Water Code, quoted hereafter: "20045. Except as herein provided, no bond issue of any dis- trict shall be approved for certification which together with any other outstanding bonds and bonds authorized but not issued of the district exceeds 60 percent of the aggregate value of the property D-l4 owned by the district or to be acquired or constructed with the proceeds of the bonds proposed to be issued by the district and the reasonable value of the land within the district. "The foregoing limitation shall not apply to bond issues pay- able solely from revenues to be received from the proceeds of a contract with a corporation authorized to do business in this State if in the judgment of the commission the proposed revenues will be adequate to service the proposed bond issue, including any reserve fund requirements." Perusal of available data regarding annual costs of irrigation water in Ventura County indicates a wide range of from about $5.00 to $40.00 per acre, with a few exceptions outside of this range. The Federal census report for 1949 shows an average annual cost of water of about $15.50 per acre for the entire County. Reports issued by the Ventura County Agricultural Exten- sion Service, which include records obtained from all portions of the County, show the following: For 1951 , records from 12 lemon groves showed costs of water varying from about $3 to $68 per acre, with an average of about $21 per acre; those from 24 Valencia orange groves varying from $6 to $101 per acre, with an average of $37 per acre; and those from 6 walnut groves varying from $6 to $17 per acre, with an average of $9 per acre. For 1949, records from 18 lemon groves showed costs of water varying from $1 to $80 per acre, with an average of $19 per acre; those for 28 Valencia orange groves varying from $6 to $80 per acre, with and average of $36 per acre; and those for 16 bean acreages varying from about $3 to $56 per acre. Applications of water to the bean crops varied from 9 to 46 acre-inches. However, most of the water costs for the beans averaged from $5 to $8 per acre, with an application of from 10 to 14 inches per acre. It should be understood, however, that higher cost water from new projects for Ventura County would be used only as a supplemental supply and not as an exclusive supply. Therefore, the over-all average cost per acre per year of water applied, local and supplemental, might be low enough to induce the widespread use of a supplemental supply by agriculture. D-15 Adoption of the recommended initial plan under the suggested form of action to be taken would appear to involve the county-wide water district in two approximately simultaneous operations — sale of bonds to the extent of some $43,000,000 — and execution of contracts for water service with subordin* entities that would benefit from construction of the bond-financed works. Depending upon negotiations with the prospective purchasers of the construction bonds, retirement of them could commence soon after their issua: by levying assessments upon all of the taxable properties in the County and reducing such assessment rates as income from water service contracts commen to be received, or only bond interest costs could be paid during the initial period of development by levying lower assessments upon all of the taxable property of the County, with no retirement of principal scheduled until inco from water service contracts becomes receivable. In the first foregoing instance, the over-all cost of bond service charges probably would be less than in the second instance, but the assessment costs against the taxable properties not directly benefited by the project would be greater. There is an urgent need for supplemental water to supply the coast plain of the Santa Clara River Valley. Lands in this area are used so inten sively for irrigated agriculture and domestic and industrial purposes that their water needs exceed the ability of the pumped aquifers to transmit supp in sufficient quantity without creation of conditions conducive to the intru sion of sea water to the aquifers. This intensive land use had been made possible only through over- exploitation of the ground water supply and devel ment of a dangerous overdraft. All of the irrigation, domestic, and industr :• water users share in the same ground water supply, and all would be adversel; affected if sea water were to destroy the utility of the underground basin through continuance of the present overdraft. They are mutually responsible for the present overdraft condition. D-16 Inasmuch as the cost of supplemental water for the coastal plain of the Santa Clara River Valley would be much more than the cost of pumping ground rater, and all water users would benefit from such a supply whether or not the 11 3upply was used directly, question arises as to determining some equitable criterion under which all water users would share in the added cost of the supplemental supply. An answer to this question might lie in the adoption of 13 i method similar to that now being undertaken by the Orange County Water )istrict. It has become evident to the people of Orange County, after some ; " 25 years of effort and failure, that the encroachment of sea water and the ^ sventual ruin of their ground water resources cannot be prevented by uncoor- iinated, piecemeal efforts. They have apparently decided that some effective igency must be given the power to manage and operate the ground water recharge program, to collect sufficient taxes on some reasonablj' equitable basis to pay for the necessary imported supplemental water, and to administer the program. Senate Bill No. 91, passed by the Legislature in May, 1953, broadens the powers Df the existing Orange County Water District to accomplish this program. The i Dill provides, among other things^ for the assessment of land and improvements, it for a pumpage tax on water extracted from the basin, called a "replenishment issessment", and for registration and control of all water- producing facilities. If the principle of the foregoing Orange County method were adopted in Ventura County, a pumpage tax could be levied against all ground water users In a given basin on the basis of annual water production. For illustrative purposes, alternative methods for fixing these charges in the coastal plain of the Santa Clara River Valley are described. It is believed that these methods ;ould be generally applicable throughout the County. It is estimated in this bulletin that the mean seasonal pumpage in t,he Oxnard Forebay, Oxnard Plain, and Pleasant Valley Subunits approximates $5,000 acre-feet. Of this amount, under the recommended plan of water D-17 ■ development, about 44,000 acre-feet of supplemental water would be supplied by surface conduit to a portion of the area presently served from ground water. However, the present cost of ground water supplies is appreciably cheaper than would be the cost of the supplemental supply. Assuming that all water users in the area are mutually responsible for the overdraft condition, and therefore should bear all costs of alleviatin, this condition proportionately, then that portion of the water users continuin to utilize the ground water supplies would, in addition to paying for the cost of pumping ground water, also pay a pumpage tax. This tax, based on a per acre-foot of pumped water, would be sufficiently high to raise funds with whicl to purchase the necessary supplemental supply and would be used by the local water district to subsidize the users of the supplemental surface supply to th extent that all users in the area of overdraft would pay about the same unit cost for water. An alternative to the foregoing method would be to levy an ad valore tax on the real property, the revenue from which would be used to reduce the amount of the required pumpage tax. If an ad valorem tax were levied at the rate of, say, $1 per $100 of assessed valuation, and if a total assessed valua tion of $40,000,000 for the area be assumed, the annual income from this sourc i- to be applied on the annual cost of the supplemental supply would amount to about $400,000. Thus, the required pumpage tax on ground water users would be reduced and, similarly, the 44,000 acre-feet of supplemental water could be sold at a lower price. There is considerable justification for employing a combination wate toll and assessment method as a means of raising the required revenue for sup- plemental water. In many cases, high-value properties in urban and industrial areas have a relatively small water requirement. Nevertheless, they benefit substantially from the intensive agriculture that is prevailing in the D-18 :•. !: ttt surrounding area, by furnishing goods and services to the farmer in his crop production and marketing. An increase in over-all water costs to the operators of such high-value properties would not increase their costs of doing business nearly as much as it would to the farmer. In lieu of levying an assessment upon the real property described above, increased unit cost rates for water could be charged to the nonagricul- tural users. For instance, of the total seasonal delivery requirement of 35,000 acre-feet of water for the coastal plain of the Santa Clara River Valley, it is estimated that about 10,000 acre-feet per season of supplemental water could be sold to urban entities. Therefore, if one arbitrarily assumes an average cost of $20 per acre-foot to pump 41,000 acre-feet and to make avail- able a supplemental supply of 44,000 acre-feet, then 10,000 acre-feet of the supplemental supply might be sold for possibly $50 per acre-foot for urban use. Thus, the average annual cost of the remaining 75,000 acre-feet of water utilized could be reduced from $20 to about $16 per acre-foot. The foregoing suggested methods of financing supplemental water supplies for the Santa Clara River Hydrologic Unit could be undertaken by the Jnited Water Conservation District if granted certain additional powers. It is not believed that this District now has the power to implement any kind of a program that would be based upon a pumpage tax. Therefore, authority would lave to be requested of the Legislature for it to do so, as has been done by the Orange County Water District. Also, the financing programs could probably De carried out by an adequately empowered improvement district created within :he United Water Conservation District. A factor that should enhance the security of any general obligation Donds that would be presently issued in Ventura County is the probable future rate of increase in assessed values. During the past 10 years, from 1944-45 D-19 to 1953-54, inclusive, total assessed values have increased an average of $17,700,000 yearly. If only a $10,000,000 increase annually occurred in the future, there would be an aggregate increase of $100,000,000 a decade hence. With partial rectification of present adverse water supply condi- tions, such future growth in valuation does not appear unlikely. D-20 PLATE I DEPARTMENT OP PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION LOCATION OF VENTURA COUNTY ' L r 1 ^ «'•: I 1 , ; i 1 ..,. T „ ^ . - . ... -si s.» NT N fiw \v o """ ^ \ ^ •^ \ \t*- ^ P^ ^VENTURA V MBXIC" LOCATION MAP FLOOD CONTROL DISTRICT ZONE NUMBER STATE Of CALIFORNIA DEPARTMENT OP PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION MAJOR WATER DISTRICTS 1953 ■pj — r \ L I "l_. r~ef | KOUJ C OUNTY ^X_. -j -jg ,--. - ' VE NTURA™ COUnTy J \S 1 i A • = i -^i— — -* COUNTY ^ LOCATION MAP LEGEND IT BOUNDARY SUBUN1T 80UN )AHY PI RU NAME OF SUBU« STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION ■ HYDROLOGIC UNITS 1953 MILES e io [p ~*~1 A } ' , ,: , - 1 « ..,.„.... ^ ft rB *" c \«I« M.PPEO. \j tsElat \ ■*» V-s--**--- 3 ' LOCATION MAP PRINCIPAL DRAINAGE AREA BOUNDARY SECONDARY DRAINAGE AREA BOUNDARY PRECIPITATION STATION STATE OF CALIFORNIA DEPARTMENT OF PU8LIC WOfiKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION LINES OF EQUAL MEAN SEASONAL PRECIPITATION IN INCHES 1897-98 THROUGH 1946-47 MEAN SEASONAL PRECIPITATION 18.76 INCHES PLATE 5 RECORDED SEASONAL PRECIPITATION AT OJAI PLATE 6 2 % > ?\-i w i N ° UJ V i^l. . . , s s - t ^_,___ : _: L j\ 2 i H ^ __A_ .. 1 / v \__ r y__.S £ < 0- J.-h - n,t Sf- \ A ._[ ? ^ ^ _f __-:\ \ a o i . j , ]. Q- cc T l x \ Q _, « rJ L t\ ] r ____ q g -,oo ^---1- - . $«___.,___ L- s 1 \J - " - \ J L__ 3 5 - ____« - _ r $,.[ y 1 Si ^ 3 AC C 1894-95 1899-1900 1904-05 1909-10 1914-15 1919-20 £ ° *> ° 2 ° i i ? T i V *)- o> ^- o> **" en i Ol 01 01 ACCUMULATED DEPARTURE FROM MEAN SEASONAL PRECIPITATION AT OJAI DIVISION OF WATER RESOURCES r | 1 A • ' \ * ; X. JL > ■"■'¥■" \ -si ... NT . & V •a "*"= (S s % ^ ° \ + , \. t^"* VjEinw \ »MI« LOCATION MAP LEGEND — ^^^ PRINCIPAL DRAINAGE AREA BOUNDARY SECONDARY DRAINAGE AREA BOUNDARY ▼ RECORDING STREAM GAGING STATION , ACTIVE V RECORDING STREAM GAGING STATION , IN ACTIVE ® SURFACE WATER SAMPLING STATION .£ DRAINAGE WATER SAMPLING STATION STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION STREAM GAGING AND WATER SAMPLING STATIONS 1952 MEAN SEASONAL RUNOFF 93,900 ACRE-FEET PLATE 8 ESTIMATED SEASONAL NATURAL RUNOFF OF SESPE CREEK NEAR FILLMORE PLATE 9 400 -p t- 2 300 - 4-4- /5 -S s t/j- \( ^ Ij -i L " " ■ T J*"l a m 5 l0 ° 1 ~-i— uj i " o -hi- i h - >- _.__\__J- nSt-S ° £ ° T ttlV ____\ __\ " "- — t """ " T7 ' K \ __._ K _ *L f" t , h l L___ => "" \ 11 ___5 \ \± \ \ ..__±_5___ J; cr -300 \ -p 1 V__/ v_ Q - 1 4-1 J TV-|- - V- ■* If i- t o> en o> ACCUMULATED DEPARTURE FROM MEAN SEASONAL NATURAL RUNOFF OF SESPE CREEK NEAR FILLMORE DIVISION OF WATER RESOURCES —I GEOLOGIC LEGEND SEDIMENTARY FORMATIONS -(H -=,„, „ Qmc SON PEDRO FORMATION PLEISTOCENE' ^ | POm I SANTA BARS* QUATERNARY jgoceneJ |'% :';| asn S...LE. i»«! in EOCENE j- ™™n """' 5 "" u " Fe " WEL '- S ALEOCENeI W^ ' I UND MARmE* T SAN0STONE : . E s'M«LE D aN0 IGNEOUS AND METAMORPHIC ROCKS QD »«rffiS.'«!fi.KnaKBB CRETACEOUS L PRE-CRETACEOUS LOCATION MAP DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION AREAL GEOLOGY 1953 PLATE II r A r - 1 <^ Y fit. Vsa -*£a-3«'. cs \ *■ "t ll P^\ ^-VENTURA V ^=?= 5 fc : ^ -^ COUNTY ^ MEXICO LOCATION MAP LEGEND ■.■■.■■■■-■■■■■ GROUND WATER BASIN BOUNDARY •35NI KEY WELL E E' LINE OF GEOLOGIC SECTION STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION GROUND WATER BASINS 1953 Scale of miles 115 5S5 « J * g ^Recent Alluvium Sespe Formation " e ^ot I I a "d P/ e'stocene Deposits Undifferentiated Tefti» r H fo" 1 \*1 — \ 3 5 ^ - * 1 = j - / 400 . y ^^^3 . - % h 3 / — i^-T!-:-"'-i^ SS-^ II -I "-- 1 / I " 200 — - „,j . ^Recent and Upper Pleistocene >' 11 / _ N v * o Deposits - .,- V / ; 1 / --*-]■ - - „- ,* 1 c- / -i — -' °7* *. *.».L y ■■/ 5 / / *% // / /,' / / - -200 r » 'X / : S - " Undifferentiated Tertiary Formafions Meon Sea leve/ DEPOSl ED = SECTION F - F OJAI BASIN NORTHEAST k / \ — | 1 \ / \ il P so I 52 / \ 55 3 55 5 5 55 / o " ZZ «" \ *7 U_ ^ ^v PIRU 1 ^^_ E^_^- 'A - - 600 % -V "fT^ .■■■■■- -j-v;,- r ,'j J.,- if \ , Recent and Upper Pleistocene Deposits SI _;.; f f-'^-jp \° 400 el --__,_ -i -*^ w - °7 - 200 ^/ San Pedro Formation Mean Sea Level i SECTION J - J' PIRU BASIN DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION geologic sections e-e',f-f;g-g',h-hand j-j' SECTION H - H FILLMORE BASIN - '_ 3 i 1 PLE 6SANT • : E , k ! V ALLE 1 i i III 1 i v-\ i west la; \ftece < > nt : POSAS BASIN^.^/ j ^^ \>*^V // - d°- ^ Recent k i • »< Upp c A Plei si ^ ° A/ ,: ■ ' e f : Vi 1 i i .,- u i= r !____ — — - 1; i t ■l \ \ \ \ v r ,1,1,1.1,1,1.1,1.1.1.1.1,1.1.1. 1 % v 3 - - □ i VENTURA COUNTY INVESTIGATION GEOLOGIC SECTIONS K-K',L-L AND M-M' 1953 SECTION M-M' OXNARD PLAIN AND PLEASANT VALLEY BASINS" NOTE. PLAN OF SECTIONS SHOWN ON PIATE PLATE 12-C SECTION N - N SANTA ROSA AND EAST LAS POSAS BASINS SECTION P - P SANTA ROSA AND EAST LAS POSA5 BASINS SOUTHEAST 3 5 5 3 SANTA 5USANA format'"" 5 Tertiary □ — SECTION R - R SIMI BASIN DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION GEOLOGIC SECTIONS N-N',P-P',Q-Q' AND R-R' 1953 SECTION Q - Q' SIMI BASIN PLATE 13 SOUTHWEST Pacific Ocect-riy NORTHEAST note: Arrow* show direction of movement of ground water in foil of 1951. LEGEND HYDROLOGIC GRADIENTS SPRING 1944 FALL 1951 DIVISION OF W4TER RESOURCES VENTURA COUNTY INVESTIGATION DIAGRAMMATIC SKETCH OF OXNARD FOREBAY AND OXNARD PLAIN BASINS PLATE 14-A PLATE 14-B VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYDROLOGIC UNIT LINES OF EQUAL ELEVATION OF GROUND WATER FALL OF 1936 PLATE 14 C .................. APPROXIMATE BOUNOflfiY OF VALLE S J jVJ J NAME OF HYOROL.OGIC UNIT Oft SU( —9oo— s/ F \°r ""» E „ L „ E , v .\" 0N of VENTURA COUNTY INVESTIGATION CALLEGUAS-CONEJO AND MALIBU HYDROLOGIC UNITS LINES OF EQUAL ELEVATION OF GROUND WATER FALL OF 1936 PLATE 15-A HY0ROLOG1C UNIT BOUNDARY SUBUNIT BOUNDARY BOUNOARY OF VALLEY FLOOR OjAJ NAME OF SUBUNI1 DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION VENTURA HYDROLOGIC UNIT LINES OF EQUAL ELEVATION OF GROUND WATER SPRING OF 1944 PLATE 15- VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYOROLOGIC UNIT LINES OF EQUAL ELEVATION OF GROUND WATER SPRING OF 1944 PLATE 15-C V 10 JXIMATE BOU eouN J / Nl J NAME OF SU6UN T 20 ifATf ELEVflT 20 »n OF EQUAL H IN FOX CA «VON A1 950 ,■/•'. rVcSr ELEVAT ROCKS VENTURA COUNTY INVESTIGATION CALLEGUAS-CONEJO AND MALIBU HYDROLOGIC UNITS LINES OF EQUAL ELEVATION GROUND WATER SPRING OF 1944 PLATE 16-A VENTURA HYDROLOGIC UNIT LINES OF EQUAL ELEVATION PLATE 16-B n. —go — s d ; E F o o u « A c.~™rio°" F °E» ' m~n s^.T.r E °» u E r" AT " EL "" | 1 ABEAL EXTENT OF LAN01 1 | IN PIEZOMETRIC SURFACI VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYDROLOGIC UNIT LINES OF EQUAL ELEVATION OF GROUND WATER FALL OF 1951 PLATE 16-C / •\ OXNARD/ £ 1 JVJ J SUeUN'T 80UN0ARY APPROXIMATE 60UNDAR1 OF VALLEY FLOOR T OR SUBUNIT VATION OF CROUNO 20 ... 900 LINES OF EQUAL ELE \3sCi: VENTURA COUNTY INVESTIGATION CALLEGUAS-CONEJO AND MALIBU HYDROLOGIC UNITS LINES OF EQUAL ELEVATION OF GROUND WATER FALL OF 1951 PLATE 17-A f L- t - ^ I ii\ -»- E - T ~"-~, -r--\ -A = i } .•s~ \ ,-- ^>' \ ■-«»» .. *! vfl t] ,'h fflr 8 ^ ' - _ I 1 jk ZS>k- ';' l';^ v - \ (Hi 0/ / ■':::: \ x ^ $01^^ x -JZZi. 1 ^ \{)v v rv * -/• 2lyC J L~ " ^J p KVv Oi / r (•„ \/v*S« *^=*^ KsJiLis. \ /^X, ' ^*\, VENTURA COUNTY INVESTIGATION VENTURA HYDROLOGIC UNIT LINES OF EQUAL DEPTH TO GROUND WATER FALL OF 1951 PLATE 17-B [ ! L — v, "v.-"-"'" L_ .^—^.i^H--- i ■i\ vr^Y 1 ) 4jp a^-p-rfy 'ii fxTV \;raiL™^ ^ ' J3^y<..\ \ \ \ % \W*1 |^Fr9^ vAj^iX p,^— -y^* V r"' s' "V S ^ V^Ca^ Big 53;.... - . ■■. -■■ - .V iTE eOUNOfldt OF \ DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYOROLOGIC UNIT LINES OF EQUAL DEPTH TO GROUND WATER FALL OF 1951 PLATE 17-C PLATE 18-A f - L V v -„■•"■" 1 1 A «s ^ Y -! a r^v- /\5 ^ ._ Jlt ^. M 1 ^ Y <\ f L i / (.''ft / 1 - A~ *. vAfy -.- ^L: 2 > 1 1 1 IrA X\ v '■mfc • . . /..A \ \ -,1 __'- c,/ 5 ^ ■^tssi ^ ■ \\ l\\ 'V ^~^— I /J -' - 1 e> '• '"""'s §\\ '/ / x^sS /' ' •v vS« *£>==»/ !"^l§L^=. \ ..> j»\# sg^BSH***^. VENTURA COU NTY INVESTIGATION VENTURA HYDROLOGIC UNIT LINES OF EQUAL CHANGE IN GROUND WATER ELEVATION FALL OF 1936 TO FALL OF 1951 PLATE 18-B me : of ^.juiL ■■ ATER ELEVATION NES OF EOUAL C ELEVATION DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYDROLOGIC UNIT LINES OF EQUAL CHANGE IN GROUND WATER ELEVATION FALL OF 1936 TO FALL OF 1951 PLATE 18-C f l_.., \ ■:„-■■•""' i w,^^ .», IjjiL, •■ ^"p%.™._ 1 ?i ;-'' ^ H \ ~/) ^ ^^» \ l^ " ' '- x - -J 4 ""^ % ^\^^^F^ WlS^"^*^; ITE BOUNDARY Of VALLEY FLOOR VENTURA COUNTY INVESTIGATION CALLEGUAS-CONEJO AND MALIBU HYDROLOGIC UNITS LINES OF EQUAL CHANGE GROUND WATER ELEVATION FALL OF 1936 TO FALL OF 1951 r\ i s: PLATE 19-A VENTURA COUNTY INVESTIGATION VENTURA HYDROLOGIC UNIT LINES OF EQUAL CHANGE GROUND WATER ELEVATION SPRING OF 1944 TO FALL OF 1951 PLATE 19-B P1F1U ...E.M DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYDROLOGIC UNIT LINES OF EQUAL CHANGE GROUND WATER ELEVATION SPRING OF 1944 TO FALL OF 1951 PLATE 19-C 1 L — , L._ .-i- >-r;, w , i li\ "i S . r ~~* - V X* \ : 4 \ i, -ff '/Wi.\L ■\ v44'r^ «']7piii|M?^\\i "% \\ V^AT fiiiK ^ \ ^Cci>^r ! •"• wfj^cr 5 ^**^ ■ -U -..-- d r OF VALLEY FLOOR -20 -40 ■ EOLPAL CHANGE IN < DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION CALLEGUAS-CONEJO AND MALIBU HYDROLOGIC UNITS LINES OF EQUAL CHANGE IN GROUND WATER ELEVATION SPRING OF 1944 TO FALL OF 1951 PIRU BASIN ELL 4N/I9W25L4 ... ;- ,-,« ■" ~\-\ i, UL _ ^ _ _ JJU ■■"■ JJU k \ n UJU \ "■" \ UIU \ \ \ uuu V \ \ lUu \ IUU y " IUU *E*s=!=*: iE^s^-k OXNARD FORE WELL 2N/22W23H BAY ,H2,H s . i.U, Sj ., r-. /s A / V \ V, / '^ V \ / \ \ •\ r- \ V V z^- \, V V / \ / HI HZ — Hi moui\ WELL D BASIN 2N/22WBN h4- A A jl_a AJT A/t/vt 1 1 A " u , "v/ v in V /w^T-~l HJ OXNAR1 WELL 1 ) PLAIN /22W7DI 1 1 1 Mil rn ,; v^w^ v - H^vt — , •i\\ \ • -VA/UN 1 vw OXNARD PLAIN WELL IN/22W3F4 G „ U(10 su „ tCE ELty »„ 01i 94e 7C | {III 1 1 1 1 1 II V^M ^ MA^ki , V ^ " V »\ V. j L 1 A A.A A/U VV l/1 /IwWU v K VTi 1 " V | r 'J- - ^llW vy II I I "I WE ST FOX WE .AS POSAS CANYON AQU LL 2N/2IWI BASIN FER SRI DROUNO .;; ,, JU IU EAST LOS POSAS BASIN EPWORTH GRAVELS WELL 3N/I9W29F3 OH0Jh - EAST LOS POSAS BASIN FOX CANYON AQUIFER WELL 2N/20WI0RI GB0UN J I \ V \ V \ \ r- A. As A V N. W PLEASANT VALLE1 FOX CANYON AQUIFER WELL 2N/2QWI7J3 > i A \j v 1 IX K \r- PLEASANT FOX CANYOI* WELL IN VALLE-i AQUIFER 2IWI6AI ~r IV 7^ / N, \/-~ 2 Si \ 1 1 i 1 V 1 / \ ^ V \A A j Tfl \ nn v / j ilU r w _ 1 SIMI BASIN WELL 2N/I8WI2L3 / \ V l> -\ V / --^ L \/ X •\ TIERRA REJADA WELL 2N/I9WI40I \ SANTA ROSA 8ASIN WELL 2N/20W23RI M0UI( su , Fltt tLEV ,„ 0N ,„ . » A /V~ \ . / \ ~\ ~\ / ^^ \ \n „ A r~"\ , // f A V-^ M/ ^> M V V\ A ' \ / V 1 ^ OJAI BASIN WELL 4N/22W5LI 6BOUK0 ,„,,„„ elevation 1.0. "° 1 1 ' 1 1 1 ' 1 ft I R . A \ A f\ 1 V \ T\if\ 1 if \ . v-i J_ \T \ /V 1 \ 1 vi V 1 ' \ / -i ■ AT Tl '3~ 1 7SO I A A/I U \/\ Z ■11 \ A \h ' I M ' V 7,0 \ l h A "• \h , ^ * \ Hv- iv "0 ''I t ,0° '■■• - A it J 1-4- "0 - ft III \ I III -H «« ii-t «0 : 1 III UPPER VENTURA RIVER BASIN WELL 4N/23W20J2 . OUHD su „ 1 ' 1 ! — k \ a A/ N \A/ r "i\r "V\ - ~\i\ x V/ 1 y 1 Y 1 1 FLUCTUATION OF WATER LEVELS AT KEY WELLS NOICATES PERIC HIGH WELL FLOWEO PLATE 21 575 _l 1 1 1 1 1 1 1 III 1 1 1 1 'Mil MM MM 1 ll l 1 1 1 1 II 1 1 II 1 1 1 1 II MM 1 1 1 1 1 1 II : PIRU BASIN WELL 4N/I9W-25L4 : 3 K : O ^^ : ^•Ck-MAXIMUM BAS N DEP tETION - FALL 1951 : 3 1 \ > : HI V \ ': z FILLMORE BASIN WELL 4N/20W- 36N2 - CXJ«A XIMUM BASIN DEPL :tion- FALL 1951 ^ * 300 ^ ^ : ': < 250 ; ; > " 200 SANTA PAULA BASIN WELL 3N/2IW-20MI ; VHA XIMUM BASIN DEPL DION- FALL 1951 ': < 150 S > \ \ \ : O 100 z o N 'S N : ; t- < > 50 b] -J OXNARD F0REBAY WELL 2N/22W-23H3 ; \ ,.•£ STIMA rED s AFE DEPLETION \ >•» M AXIMUt 1 easir DEPL ETI0N - FALL 1951 - -50 i i i i 1 1 1 1 III. \ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , , , , 1111 , , , , ' '; : - " - =— ■ ^ - - . " SI M 1 BASIN - - v WELL 2N/I8W- I2L3 - - t) MAXIMUM BASIN DEPLETION* : " \ FALL 1951 - " \ - " \ - 1 : 10 15 20 25 30 35 40 45 50 GROUND WATER STORAGE DEPLETION IN THOUSANDS OF ACRE- FEET 10 20 30 40 50 60 70 80 90 100 410 120 130 140 150 160 170 180 GROUND WATER STORAGE DEPLETION IN THOUSANDS OF ACRE-FEET 1 1 I 1 1 1 1 1 1 1 1' l ! 1 1 1 \ 750 : '- K ESTIMATED SAFE - ■^ DEPLETION OJAI BASIN . 700 NELL 4N/22W- 5LI - 650 _ - 600 • MAXIMUM BASIN DEPLETION _ FALL 1951 - N " iii III i i i i \ ■ i I I 10 15 20 25 30 38 40 45 GROUND WATER STORAGE DEPLETION IN THOUSANDS OF ACRE-FEET RELATIONSHIP BETWEEN WATER LEVELS AT KEY WELLS AND GROUND WATER STORAGE DEPLETION DIVISION OF WATER RESOURCES PLATE 22 WELL LN/22W-29A2 WELL IN/22W-20R1 WELL IN/22W-20NI POINT DATE NUMBER SAMPLED CHART A Al 3-31-47 A2 5- 5 -49 A3 5-25-51 A4 7-25-51 A5 9-4 -51 A6 II -27-51 A7 3-2B-52 AS 6- 6-52 4-3-31 9- 4-31 6- 3-32 3-3-33 7-21-36 12-20-39 9-27-45 4-30-48 7-16-48 10-7-49 10-8-49 3-23-50 HC03 80 60 %S04 40 20 CHART A-CLASSIFICATION OF ANION CONSTITUENTS S04 POINT NUMBER DATE SAMPLED CHART B WELL IN/22W-28DI Dl 02 D3 D4 D5 D6 6-5-31 6-9-31 6-26-31 6-26-31 6-3-32 3-3-33 Low Tide) HiqhTide) CHARTS A ANO B SEA WATER S.W 5-1-52 DRAINAGE DITCHES 2 3 4 5 6 7 B 6-4-52 1 - 14-53 1-14-53 6-4-52 8-4-52 6-6-52 1-14-53 B- 4-52 LOCATION IN/22W- 7 J 1N/22W- 7J IN/22W- ISA 1N/22W- ISB 1N/22W- 21B 1N/22W- 2IF IN/22 W- 2 IF IN/22 W- 2IQ 9 10 6-6-52 B-4-52 IN/22W- 27C 1N/22W- 27C 1 1 1-14-53 I N/22 W- 27C 80 60 %S04 40 20 CHART B-CLASSIFICATION OF ANION CONSTITUENTS HCCb LEGEND • WELLS A GROUND WATER DRAINAGE X SEA WATER NOTE— SEE PLATE II FOR WELL LOCATIONS. MINERAL CHARACTER OF GROUND WATERS IN VICINITY OF PORT HUENEME AND POINT MUGU DIVISION OF WATER RESOURCES PLATE 23 4 2 _ 4 < 2 Q d 3 -2 u! -4 z -6 cc 5 -8 | HO O o -12 o z -14 o 5 -16 > Mill Mill 1 1 1 II 1 1 1 1 1 1 1 1 1 1 Mill Mill II 1 II Mill 1 1 1 1 1 MM II II 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 \ Mean Sea Level \ V r *V -4 600 -6 580 -8 560 540 ELEVATION OF GROUND WATER AT WELL IN/22W-20RI 580 560 540 520 500 -10 -12 520 -14 500 460 440 420 400 380 360 340 320 300 280 260 240 220 200 180 160 140 120 100 80 60 440 420 400 380 360 2 340 _J * 320 cc a. 300 VJ J 280 i 260 z 2 240 < cc l- 220 z z 200 o z 180 o u 160 o cc o |40 I 120 100 80 60 40 CHLORIDE ION CONCENTRATION AT WELL IN/22W-29A2 Mill 1 1 1 1 ' 1 " 1 1 1 1 1 ' 1 1 1 1 1 I I i I I i i i i i i i I i i 1 1 1 1 1 Mill i i i i i 1951 1952 ELEVATION OF GROUND WATER AND CHLORIDE ION CONCENTRATION DIVISION OF WATER RESOURCES PLATE 24-A LEGEND ^^^™" HYDROLOGIC UNIT BOUNDARY ■ ^ ^ SUBUNIT BOUNDARY APPROXIMATE BOUNDARY OF VALLEY FLOOR OJAJ NAME OF SUBUNIT IRRIGATED LANDS IRRIGABLE AND HABITABLE LANOS URBAN AREAS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION VENTURA HYDROLOGIC UNIT PRESENT AND PROBABLE ULTIMATE LAND USE 1950 PLATE Z- I ( : T^Wfe^J" i II \ C" J ij ^ ^-^^s ^^ QHBfe x^^^pi^^s *'O^J<^^ ,^y/?y »a. VENTURA COUNTY INVESTIGATION SANTA CLARA RIVER HYDROLOGIC UNIT PRESENT AND PROBABLE ULTIMATE LAND US 1950 PLATE 24-C OXNARb/ ,^Jf^ \~\. — i L -— L, \ \"" ! Wfep^-- A !\ V>r-*sr- V si\ ..... v ^* T '! ) f^~^^%\. \ < ><\ , ,..../> \\ " jsas_» =.,/ p'^^pn A\ --'!' "X X X jfiMS ^ >\' - vMf ^mMSliffl - \\^fi^> ; ^^m|fjL VvK^Sj/S*^ % \^?^?N* f ' ' U *"*-!■ 'J^*^*L r-^JJfr i-^nT&y ^_ === p^ p<^ •' - ^T; ^? v y " p555r™"" \ -' 1 DIVISION OF WATER RESOURCES VENTURA COUNTY- INVESTIGATION CASITAS DAM ON COYOTE CREEK RESERVOIR STORAGE CAPACITY OF 130.000 ACRE-FEET PLATE 27 ~ ~ — ' ~ % ."" _.- ■ , , . y ^^^^ SECTION OF DAM GENERAL PLAN I3O0 Vs r/ y ~<3r~\ -"'" f== — ~~ ^??;z::£°i"y m BOO V^ A — - ■" LENGTH IN FEET PROFILE OF DAM LOOKING UPSTREAM 01VISION OF WATER RESOURCES VENTURA COUNTY NVESTIGATION FERNDALE DAM ON SANTA PAULA CREEK RESERVOIR STORAGE CAPACITY OF 12,000 ACRE -FEET PLATE 28 SECTION OF DAM ZK^:- •. :■ ■ :,— ■■ • ■ '•:■■ ■>'- ■ *> 'S - ^>>. \ /i // ^> / ^/ ^sxarsr' - -- — - """ LENGTH IN TEET profile: or dam LOOKING UPSTREAM GENERAL PLAN VENTURA COUNTY INVESTIGATION COLD SPRING DAM SESPE CREEK RESERVOIR STORAGE CAPACITY OF 35,000 ACRE-FEET PLATE 29 ■ ^_ ■7 ^ /' X ^^ ■^ ~— ^> / •44. >^ ?z%Z7Zr^^ \ / l_ / / \ / \ / 1 ■ ^>^ 1 V- \ \ V - / / — - PROFILE OF DAM Mm/% --T— - SECTION OF DAM VATEB ■■■ VENTURA COUNTY INVESTIJATI >. TOPATOPA DAM ON SESPE CREEK RESERVOIR STORAGE CAPACITY OF 100,000 ACRE -FEET GENERAL PLAN PLATE 30 \ / 1 zinnLz '7 \ X /,< \ ^-- rV ^^^ s \ /, s ** \ S \ \ \ \ /Pi, /£-'* EXS rsr* \ \ ' \ • / LENGTH IN FEET PROFILE OF DAM LOOKING UPSTREAM DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION HAMMEL DAM ON SESPE CREEK RESERVOIR STORAGE CAPACITY OF 50.000 ACRE-FEET PLATE 31 SECTION OF DAM 1^ y\ / r\- \ // / V s~ N^ QZ^zLris' "•' xi // v J / LENGTH IN FEET PROFILE OF DAM DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION UPPER BLUE POINT DAM ON PIRU CREEK RESERVOIR STORAGE CAPACITY OF 50,000 ACRE-FEET PLATE 32 SECTION OF DAM 1500 / / VK j( s S^S )£* £ an f * . \ / v= & 1100 \ (^ / s / v --~ — ---*' LENGTH IN FEET PROFILE OF DAM LOOKING UPSTREAM BLUE POINT DAM ON PIRU CREEK RESERVOIR STORAGE CAPACITY OF 50,000 ACRE-FEET PLATE 33 SECTION OF DAM - / ^ X /L \^ . // vs s<*' ^ ^ Ns. '' \\ / ^T/JXr.t'l'i'" ^ s / LENGTH IN FEET PROFILE OF DAM LOOKING UPSTREAM VENTURA COUNTY INVESTIGATION DEVIL CANYON DAM ON PIRU CREEK RESERVOIR STORAGE CAPACITY OF 150,000 ACRE-FEET PLATE 34 . __ ^ SECTION OF DAM ^7 :sest elev iot, /~ - ~^ /? y \\ /,' \ -r v ,/£f «7/(/r« ffr^> ^ — - 1 r / * / / *» / *■ / - _ J/ - 2 -J / 7 0^ — ~ — 2 / ** / ° 1 - / iil 1 u - - _ 1 "* _ — 1 /*"■ / J? / 1 a:/ / A/ 2 - co/ /I ^/ - — Q/ / -J 1 1 o/ / °/ \^UPPER B _UE POINT - - ^BLUE POINT - — 4 ^ ^^ - - - - 1 = , 1 i 1 1 1 1 1 1 1 1 I 1 1 i 1 1 1 1 i 1 1 i 1 i 1 i i 1 i 1 i i I , = e io 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 CAPITAL COST IN MILLIONS OF DOLLARS RELATIONSHIP BETWEEN STORAGE CAPACITY OF RESERVOIRS AND CAPITAL COST DIVISION OF WATER RESOURCES PLAT E 3 6 < o z < o I z >■ < tr o O 160 140 120 100 80 60 40 20 1 1 1 1 1 1 1 1 1 1 1 1 i i i i i i i i l i i I - f//i <0 o // / i// S / - iff* i/ 7 to/ / / - 9> 1/ / *ir/ // v y - _ UPPER BLUE PO _ AND BLUE POINT INT // / ^° / / - Xi M 4- sK :\z:::'z\zz: :zt ,°l„- - /* 111! III i i i i i i i i i i i i i i i 5 10 15 20 25 NET SAFE SEASONAL YIELD IN THOUSANDS OF ACRE-FEET 30 RELATIONSHIP BETWEEN STORAGE CAPACITY OF RESERVOIRS AND NET SAFE SEASONAL YIELD DIVISION OF WATER RESOURCES PLAT E 3 7 i r CASITAS j, _ (INCLUOING 200 SECOND-FOOT DlVERSOfJ) COLD SPRING i I r 1 r^^ i — I — r i — i — r J I I L_l J I L 1 I 1 I I I I L 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 AVERAGE ANNUAL COST PER ACRE-FOOT OF NET SAFE SEASONAL YIELD IN DOLLARS RELATIONSHIP BETWEEN NET SAFE SEASONAL YIELD OF RESERVOIRS AND ANNUAL UNIT COST DIVISION OF WATER RE SOURCES PLATE 38 400 9& ^ >*P ^ 1 1- u Ul u. tu < o ts> D 200 ISO 100 V%" *£ *s^ o] '& $& ^ «£& gfOjiS vt«22i! ^^- — < ■ 3 O X 80 70 &l £&> oo^ Z >- 1- o < Q- 50 < o i- K O > IE IT 15 10 c i 2 1 t i ( " i E 1 i i i i 2 13 14 15 16 17 18 19 20 AVERAGE NUMBER OF SEASONS REQUIRED TO FILL RESERVOIR PROBABLE TIME REQUIRED TO FILL RESERVOIRS AFTER CONSTRUCTION DIVISION OF WATER RESOURCES PLATE 39 DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION FEATHER RIVER PROJECT - _ 4000 TURNOUT FROM MAIN CONDUIT WATER SURFACE ELEVATION 3324 8 A - 3800 / REGULATING RESERVOIR IS \ A WATER SURFACE ELEVATION 3323.5/^ ^& A k h A a SIPHON - 3400 > ^jS jpf \ ^6^Ud\^ /WATER SURFACE ELEVATION 3290 WATER SURFACE ELEVATION 1885 ~ TUNNEL ^Z TUNNEL\ - - INTAKE ELEVATION 3310 - - V PENSTOCK - 2600 - \ WATER SURFACE ELEVATION 2475 Li \ " _ POWER PLANT No. 1 ^^Lt^ WATER SURFACE ELEVATION 2275 1 \A _ ^^^ \ - f ' TUNNEL \ f 1 - 2200 - / INTAKE ELEVATION 2260 PENSTOCK->- POWER PLANT No. 2 -*H 1 1 \ l\ M " ■4 TUNNEL - INTAKE ELEVATION 1870 i^-PENSTOCK - - DEVIL CANYON RESERVOIR - 1400 - POWER PLANT No l~*- WATER SURFACE ELEVATION 1265 - i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , , I 1 , , I 1 , , , 1 , , , 1 , , , 1 , , 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I 1 I I , 1 , I , 1 , 1 , I 1 , , I 1 I , 1 , , 1 , , , 1 I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 " 20 24 26 32 36 40 44 48 52 56 60 64 68 72 76 80 DISTANCE IN THOUSANOS OF FEET 92 96 100 104 120 124 126 OIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION PROFILE OF POSSIBLE VENTURA COUNTY DIVERSION FEATHER RIVER PROJECT 200 220 240 260 280 DISTANCE IN THOUSANDS OF FEET DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION PROFILE OF PROPOSED VENTURA COUNTY AQUEDUCT TO CONNECT WITH SYSTEM OF METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA CAPACITY 150 SECOND-FEET PLATE 42 _ J i \ NATION A^^ t / \ / \ > -OJAI CONDUIT VENTURA RIVER-CA5|TA5 DIVERSION fiu ■ 5" ">t_ lc~ - - >LQi L r-2 5 -/i7" N " , 5- ^\ "I / SANTA CLARA jRIVER CONDUIT *' 'Jf f ' t-ja£«*S K\i * /• ^J^f-jzs^, ^^£_ A^ ~ THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW ANJMITIAL FINE OF 25 CENTS o»\*i z\ s 7j°*:t ke to return th,s *°°< j JCD LIBRARY DUE r EB 15 1973 pee 1 3 recd MAR 2 4 1982 Book Slip-10m-8, , 58(5916s4)45S 17322U Calif, iitate water re- sources board. Bulle tin. Itf. Call Number: TD201 C2 no. 12 PHYSICAL SCIENCES LIBRARY 17^224 3 ,! m *