THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS STATK OF C\L1F0UNI\ DEPARTIVIENT OF PUBLIC WORKS Publications of the DIVISION OF WATER RESOURCES EDWARD HYATT, State Engineer Bulletin No. 46 VENTURA COUNTY INVESTIGATION 1933 S36^ -8375 CALIFORNIA STATE PRINTING OFFICE HARRY HAMMOND. STATE PRINTER SACRAMENTO. 1934 f 'BRARY UNIVER^. .'OF CALIFORNIA DAVIS TABLE OF CONTENTS Page ACKNOWLEDGMEXT 11 ORGANIZATION 12 PERMANENT COMMITTEE 13 FOREWORD 14 Chapteh I SUMMARY AND CONCLUSIONS 15 Work done If) Water supply 17 Basic assumption IT Summary 17 Conclusions as to water supply 20 Development plans 22 Santa Clara Valley and Calleguas Creek Basin 22 Spreading- grounds , 23 Estimated salvage by surface reservoirs 23 Pumping in Santa Paula Basin 26 Conclusions — Santa Clara River Valley, Calleguas Creek Valley and Oxnard Plain 27 Silt problem 28 Ventura River Basin 28 Conclusions — Ventura River Basin 28 Conflict with highway on Pine Creek 29 Conclusion 30 General summary of conclusions 30 Chapter II GENERAL DESCRIPTION 32 Santa Clara River 33 Calleguas Creek 33 Ventura River 33 Chapter III GEOLOGY 35 Areal (Jeology 38 Relation of the tertiary formations to the alluvial basins 38 Eastern Basin 38 Pine Basin 40 Fillmore Basin 40 Santa Paula Basin 41 Oxnard plain nonpressure area 41 Oxnard plain pressure area 42 Simi Valley 42 Las Posas Valley 43 Pleasant Valley 44 Santa Rosa Valley 44 Newl)urv Park Area 4u Ojai Valley 45 Upper Ventura River Valley 4:i Chapter IV HYDROLOGY 46 Hydrological Investigation and Analysis i^ Precipitation 47 Stream discharge 48 Stream percolation 48 Deep percolation from rainfall on valley floor 62 Underground contribution from porous hills and mountains 62 Storage capacity in valley All 62 Underground flow ^l* Consumption by water-loving plants 63 Irrigation exportations jj;| Use by irrigated lands "•> (3) 4 TABLE OF CONTENTS Chapter V p^^^ BASIN CAPACITIES— METHOD OP COMPUTING SPECIFIC YIELD 65 Porosity, specific retention and specific yield 65 Sand and gravel samples from Santa Clara River Valley 6o Location of samples 66 Mechanical analyses 67 Specific yield of sands 69 Specific yield of gravels 'J^^ Specific yield of clay Ij- Summary of specific yield values used for Santa Clara River Basms 73 Specific yield contours "J^^ Oxnard plain, nonpressure area ]^^ Ojai Basin ]^'^ Upper Ventura River Valley J° Basin capacities and storage changes _;.5 Change in storage computations ^^ Piru Basin ^^ Fillmore Basin ^jj Santa Paula Basin '•* Oxnard Plain nonpressure area ol Ojai Valley I] Upper Ventura River Valley ot Chapter VI RAINFALL PENETRATION 82 Description of soils in Ventura area 82 Soil moisture studies in 1931-32 83 Factors in rainfall disposal 85 Initial soil moisture deficiency 85 Runoff 86 Evaporation and transpiration 88 Calculations 88 Chapter VII QUALITY OF WATER 91 Surface waters 93 Underground waters 96 Ventura River Basin 96 Santa Clara River Basin 97 Montalvo Basin 99 Santa Paula Basin 99 Fillmore Basin 100 Piru Basin 100 Review of the Santa Clara River Valley 100 Underground waters 100 Calleguas Creek Basin 101 Epworth Basin 101 West Las Posas Basin 102 Simi Valley 102 Las Posas Valley 102 Pleasant Valley 102 Santa Rosa Valley 103 Review of the Calleguas Creek area 103 Chapter VIII WATER SUPPLY OF SANTA CLARA RIVER VALLEY 104 Water supply 105 Conclusion 108 Chapter IX WATER SUPPLY OF CALLEGUAS CREEK BASIN 109 Simi Valley 109 Water supply 109 Use of water 110 Surplus or shortage 110 Conclusion 110 Las Posas Valley (Moorpark-Somis area) 110 Water supply :_ 111 Use of water 111 Surplus or shortage 111 Conclusion 111 West Las Posas Valley 112 Water supply 112 Conclusion 112 Santa Rosa Valley 112 Water supply 113 Use of water 113 Surplus or shortage 113 Conclusion 113 TABLE OF CONTENTS O WATER SUPPLY OF CALLEGUAS CREEK BASIN — Continued Fage Pleasant Valley 11-5 "Water supply 114 Use of water 114 Surplus or shortage 114 Conclusion 114 Chapter X WATER SUPPLY OF COASTAL, PLAIN 115 Use of water 115 AVater supply 116 Marine intrusion 117 Conclusion 118 Chapter XI COST ESTIMATE OF SURFACE RESERVOIRS 119 Los Alamos reservoir 119 Liebre Creek diversion to Los Alamos reservoir 12G Spring Creek reservoir 126 Concrete arch dam ■ 131 Gravity concrete dam 132 Rock fill dam 133 Blue Point reservoir 134 Devil Canyon reservoir 139 Cold Spring reservoir 144 Topa Topa reservoir 148 Matilija reservoir 152 Camarillo reservoir 156 Dunshee reservoir 159 Santa Ana Creek diversion to Dunshee reservoir 163 Chapter XII SPREADING WORKS 164 Detailed description of proposed spreading works 168 Piru Basin 168 Montalvo Basin IJl L'pper Ventura River Basin 173 Chapter XIII PLAN OF DEVELOPMENT. SANTA CLARA Rm:R VALLEY, COASTAL PLAIN AND CALLEGUAS CREEK VALLEY 176 Hydrological resume 176 The problem stated 177 Surface reservoirs 179 Piru Creek 181 Sespe Creek 184 Pumping in Santa Paula Basin 189 Reservoir on Conejo Creek 190 Conduit from Santa Clara River to the south 190 Sequence of development 192 Spreading works in Montalvo Basin 192 Spreading works at Piru 192 The silt problem 194 Chapter XIV VENTURA RIVER BASIN WATER SUPPLY AND DEVELOPMENT 195 AVater supply and present demand 196 Ojai Basin 196 Development 196 Underground basin 196 TVater supply 197 Conclusion 197 Santa Ana Creek Valley 197 L'pper Ventura River Valley 198 Percolation in river wash 198 Possible development Ventura River Valley 199 City of Ventura 200 Lands in Upper Ventura River Valley 200 LIST OF TABLES Table Page 1. Irrigated and irrigable area, 1932 18 2. Cost and accomplishment of spreading works Santa Clara Valley and Coastal Plain 23 3. Comparative cost of conservation by reservoirs based on type of dam found cheapest at each site 23 3-A. Comparative cost of conservation by reservoirs, spreading works not built — 24 3-B. Comparative cost of conservation of 6000 acre feet at reservoirs investi- gated — spreading works given priority 25 1. Conservation by reservoirs, "Ventura River Basin 2 -0 ^ - UJ 20 Rainfall at Santa Paula was estim- ated forbears 1892-1897. Discharge of Sespe Creek was estim- ated for ^rs I9l8-I9l9and 1926-1927. l\ ^ ^ ' \ I \ D sc ar |e Ses ?e Creeld ' "1 " r " 1 , ^Flowing! \ 1 \, '•. \ Water table elevation at well 9-U-9-^ In spring of^ear - Oxnard city well. / 'yr X - / \ A r > { \ Rair f; II a 5? nt a Pa ul: y ^-^'\ i s / \ ( s / \ / V \ J S / < r \ \ / t- \ y \ / CI JMULATIYE VARIATION FROM FORTY YEAR i ANNUAL MEA N 20 DIVISION f)F WATER RESOURCES The various divisions or basins into which the area was divided for study are as follows : Santa Clara River Valley — Eastern Basin (mostly in Los Angeles County). Piru Basin. Fillmore Basin. Santa Paula Basin. Coastal Plain — Montalvo Basin (non]n"essure). Oxnard Plain (])ressure area). West Las Posas Basin. Ventura River Valley — Ojai Valley. Coyote Valley. Upper Ventura River Vallej' . Calle(j)(as Creek Valley — Simi Valley. Las Posas Valley (Moorpark-Somis). Santa Rosa Valley. Pleasant Valley. Conditions are somewhat different in each of these and conclusions as to water supply are set out separately in the following. Conclusions as to Water Supply In the Eastern Basin, rainfall is small and the recent alluvium of the basin is shallow. Climate is such that type of crop which can be raised does not justify large expense for water. It is believed development here will be small and that it does not constitute a threat to the water supply to the valleys down river in Ventura County. Piru, Fillmore and Santa Paula basins have surplus water supply without conservation for present and estimated ultimate development. Even after the long period of drought now in progress the lower end of Fillmore Basin and all of Santa Paula Basin are so full that the under- ground water is forced to the surface along the river channel and a growth of willows is sustained which is estimated to be wasting over 12,000 acre-feet of water each year. The water table in Piru Basin lowers drastically in periods of drought but the basin will fill with normal years of preci})itatioii. Li the other two basins only moderate lowering of the water table occurs in dry cycles. The Coastal Plain derives its natural supply from overflow of water which has percolated into Santa Clara River Valley and also from percolation of floods crossing Montalvo Basin. As development increases in the valley, supply to the plain decreases. There is thought to be a small long-time shortage in the Coastal Plain with present draft and if there had been the same acreage irrigated in Santa Clara River Valley and the plain during the past forty years as there is today, and if the pumping draft per acre had been the same as during the period of investigation, the water table in the plain would now be VEXTURA fOl'XTY INVESTIGATION 21 considerably belo^v sea level. This condition thi-eatens intrusion of water from the ocean into the pumping strata. Further development in Santa Clara River Valley and in the plain will increase danger from this source. It is iirobable, however, that for the present type of crops in the Coastal Plain the pumping draft would be less in years of normal or above normal rainfall than the average during the five years of field work and if so the overdraft predicated on present draft would not actually exist. However, intrusion of salt water would still threaten. In Ojai Valley the natural underground supply is believed to average more than sufficient for present draft on it and if supplemented by sju-eading on the cone to induce artificial recharge of the basin, it is believed the supply will be snf^cient for a considerable increase in draft. Fluctuations in water table with wet and dry cycles are drastic but when the water table is high there is waste by seepage out of the gravels. When it is low this ceases and becomes available for pumping. For the basin along the upper Ventura River, information, although all available was gathered, is not sufficient to draw as definite conclusions as for the basins previously discussed. Agricultural draft on the basin is small. The city of Ventura draws most of its supply at the lower end from overflow of the ground water of the basin. There is no indication that the basin could not safely furnish a larger supply than at present by proper development. The underground waters of the valleys of Calleguas Creek are apparently derived in the main from deep percolation of rain on the porous portions of the watershed, which is transmitted under- ground to the valleys. Xo attempt has been made to evaluate this supply and hence no evaluation is made of the total supjily. Conclu- sions made are indefinite and based mainly on behavior of the water table during the investigation and the area of permeable watershed tributary to each valley. Around Simi Valley the watershed to the north is not permeable but it is to the south. The long-time average supply to the north side of the valley floor may be insufficient for present draft but it may be sufficient to the south side. The watershed of Las Posas Valley is large on the north side and highly permeable. The long-time average underground supply is believed sufficient for present draft and probably for additional draft. The watershed of Santa Rosa Valley on the south is permeable. Xo evidence was found leading to the belief that a shortage in supply exists but no estimate is attempted of additional draft which may be made. The water table stays at a remarkably constant level whethei- the seasons are wet or dry. Pleasant Valley has no large water.shed nor is it very permeable. The water table is under pressure over part of the valley and no contribution could occur from rainfall in this area. Most of the wells penetrate below the recent alluvium into the Saugus formation and draw their supply from it. It is believed the water sujiply is inade- quate for present development. With the exception of Ventura city and the possibility of intrusion of salt water in Oxnard Plain the situation as to water sui)ply does not call for immediate expenditure to remedy it in any of the basins even 22 DIVISION OF WATER RESOURCES though shortage may exist in some. While a shortage may exist in some of the valleys of Calleguas Creek Basin yet the water table can go to considerably greater depths than at present before imported water could compete in cost, even with greater pumping lift. Although water supply is believed sufficient in most of the county, yet Avhen the Avater table lowers, quality of water deteriorates and expenditure for conservation may be justified for this where it can be done cheaply as in the case with the proposed Piru spreading works. DEVELOPMENT PLANS Santa Clara Valley and Calleguas Creek Basin Numerous reservoir sites exist on Piru and Sespe Creeks tributary to Santa Clara River, as shown on frontispiece. The estimated average annual run-off of these creeks for the forty-year period beginning fall 1892 is 53,000 acre-feet and 94,000 acre-feet, respectively. Several sites exist in Calleguas Creek Basin but the average local run-off tributary to them is insignificant. Estimates of cost of reservoirs were made for Los Alamos, Spring Creek, Blue Point and Devil Canyon sites on Piru Creek, of Cold Spring and Topa Topa sites on Sespe Creek and of Camarillo site on Conejo Creek tributary to Calleguas Creek. The last would be used to conserve winter run-off of Santa Clara River con- veyed to it by conduit. Estimates were made for various capacities and various types of dams on the Sespe and Piru Creek sites. There may be other reservoir sites, particularly on Piru Creek in the canyon below Spring Creek, not found during the investigation and a careful reconnaissance should be made prior to any construction program. The sites mentioned are believed to be the cheapest possibilities but the costs as shown by these estimates are excessive. The run-off is extremely erratic, that of the maximum year being over forty times that of the minimum year while for the ten-year period 1923-1932 it is estimated to be only 60 per cent of the long-time average. The waste into the ocean for the ten-year period is estimated to be only about one-third the long-time average. This, together with the exces- sive cost of reservoirs, indicates that if built they should be built to control only the waste of the deficient periods of years as it would be prohibitive to attempt to hold over water in them from the years of excess run-off, and studies indicate that all underground reservoir capacity in Santa Clara River Valley will be fully occupied by natural percolation in wet cycles. This may be true also of Oxnard Plain even without conservation but spreading at Montalvo will assure it. No other area is naturally accessible and the valley material east of Oxnard Plain is not suitable for spreading to recharge the underground reser- voirs even if s])ace were available in wet cycles. Accordingly the studies of reservoir capacity and yield are based on the salvage possible in the ten-year period, plus the holdover from the winter of 1921-22, as tlie reservoirs would be filled in that year of prolific run-off. Studies were also made of conservation Avhicli could be accom- plished by utilizing s]iace in the underground reservoirs of Piru l>asin in Santa Clara River Valley and IMontalvo Basin in the Coastal Plain. In these basins the water table h)wers sufficiently in dry cycles so that more water could be caused to percolate into them. Piru Basin, VENTURA COUNTY INVESTIGATION 23 it is estimated, will naturally refill in wet cycles so that no more water t'ould be placed in it at such times but this would not be the ease witli ^lontalvo Basin unless, as seems probable, the draft during: wet cycles were smaller than found in tlie years in whicli the investifi'ation was in progress. Spreading grounds are proposed in these two basins to cause water which now wastes into the ocean durinfr floods to percolate to the water table. Estimated cost and accomplishment are as follows, the amount of salvage being that in excess of natural percolation : TABLE 2 COST AND ACCOMPLISHMENT OF SPREADING WORKS, SANTA CLARA VALLEY AND COASTAL PLAIN Average conservation 1922-1932, acre-feet Diversion rate 200 sec. ft. Estimated cost Name Total Per acre-foot conservation Piru 4,800 12.600 $401,000 348,000 $84 28 A cheaper plan could be worked out at each location. The diver- sion rate in each case would be smaller and the salvage less. The cost per acre-foot would be less. Estimated salvage hij surface reservoirs in the following table is from stream flow which would still run into the ocean after supplying the above spreading works, natural percolation and present diversions. The release would be regulated so that it could be caused to percolate into the spreading grounds listed in the foregoing table. TABLE 3 COMPARATIVE COST OF CONSERVATION BY RESERVOIRS BASED ON TYPE OF DAM FOUND CHEAPEST AT EACH SITE SPREADING WORKS BUILT Approxi- mately most economic capacity, acre-feet Average conservat-ion 1922-1932, acre-feet* Cost Name Total Per acre-foot conservation Piru Creek- Los .\lamos 11,600 15,000 20,000 30,000 40,000 40,000 ♦♦3,000 3,470 4,800 5,770 8,600 16,400 •♦$1,710,000 1.550,000 3,500,000 3,600,000 1,920,000 3,860,000 $570 455 Blue Point 730 625 Sespe Creek— 224 Topa Topa 366 * The ten-year period plus a full reservoir from the winter of 1921-22. ** Includes Liebre Creek diversion to the reservoir. The following table gives for the most important surface reservoirs, for which estimates wore made, the estimated salvage and cost per acre- foot assuming no spreading works are built and that all conservation 24 DIVISION OF WATER RESOURCES IS credited to the reservoirs. From tliem water M'ould be released in flows small enough so that it Avould percolate in the stream bed. TABLE 3-A COMPARATIVE COST OF CONSERVATION BY RESERVOIRS SPREADING WORKS NOT BUILT Acre-feet Cost Name Capacity Average conservation 1922-1932 Total Per acre- foot of conservation Piru Creek— 15.000 30,000 40,000 4.900 9,170 11,500 $1,550,000 3,600,000 1,920,000 $316 392 Sespe Creek — 167 Topa Topa _. , . . 20,000 40,000 and 60,000 22,000 15,780,000 $263 The three foregoing tables show clearly the comparative cost of conservation (1) by spreading works alone, (2) by surface reservoirs alone from which water could be released to percolate into the stream bed as rapidly as it naturally would, and (3) by a combination of surface reservoirs and spreading works. The cheapest conservation by spreading works alone M'ould be at Montalvo where an average of 12,600 acre-feet could be conserved annually at a total capital cost of $348,000 and an acre-foot cost of $28 for the capacity of works on which estimates are based. The cheapest conservation by surface reservoirs alone would be at Cold Spring site on Sespe Creek where for the most economic capacity an average of 11,500 acre-feet could be conserved annually at a total capital cost of $1,550,000 and an acre-foot cost of $167. The combination of surface reservoir and spreading works would not give the sum of the quantities credited to each one singly since some of the water could be conserved at either. Cold Spring reservoir and Montalvo spreading works are the cheapest combination and would give for the most economic capacity of reservoir and the capacity of works on which estimates are based an average of 21,200 acre-feet ami nail v at a total capital cost of $2,270,000 and an acre-foot cost of $107. AVliile the three tables show the much smaller capital cost of spread- ing works as compared to the cheapest surface reservoir possibility, they do not show the merits of the surface reservoirs compared one with another. The cost per acre-foot of conservation is given in each case in Table 3 for the most economic capacity of each reservoir and there are large differences in the amounts of conservation achieved by the most economic capacity of each, so that in Table 3, reservoirs of different capacities and different conservation achievement are com- pared. This may not be tlie best basis for comparison. At all sites except Devil Canyon* the cost per acre-foot of conservation increases *Becau.se of bad foundation conditions which limit the heiglit of the dam, no estimates were made of costs of hipher dams at Blue Point site and tlie most economic capacity is not known. Hence the discussion does not apply to Blue Point site. VENTURA COUNTY INVESTKJATION 25 rapidly for smaller or larg'er reservoirs than the most economic capacity. (See pages 182 and 186 <^^ypnd-feet canal ^'^^\\ ^^ second -feet pipe line ^A \ond-feet canal ::;^^"^ ^ond-feet canal ■|0N OF D CANAL 'ER TO THE SOUTH EJO^MTN TUNNEL SECTION 8367— S TYPICAL CANAL SECTION 75 second-feet capacilj/ TUNNEL SECTION 8367 — 8376— pages 26-27 VENTURA COUNTY INVESTIGATION 27 PLAN 1. SURFACE RESERVOIRS Cold Spring Reservoir (conservation S600 acre-feet) $l,H20,0t)M Conduit of 200 second-feet capacity, diverting floods to Camarillo Reser- voir when spreading works not operated (conservation 3400 acre- feet) and delivery from Cold Spring Reservoir direct to irrigated lands in years when available 1,300,000 Camarillo Reservoir 808,000 Total $4,028,000 PLAN 2. UNDERGROUND RESERVOIRS Created by Pumping (See Plate IV) (_;ra\ity diversion of rising water and pumping plant installation in lower end of Santa Clara Valley (conservation 12,000 acre-feet at least)__ $371,000 Conduit of 7 5 second-feet delivering water by gravity to Pleasant Valley lands in all years 583,000 Camarillo Reservoir (not required) Total $954,000 Either of these plans could be used to deliver water by further pumping to Las Posas Valley. The comparison indicates that it would cost about four times as much to conserve 12,000 acre-feet by surface reservoirs as it would by creating new underground capacity in Santa Clara River Valley. Operating cost, however, would be higher for the latter, but not sufficiently higher to cause total annual cost of Plan 2 to approach that of Plan 1. The above two plans are independent of the spreading works noted in Table 2, but Plan 2 would decrease the water available to spreading works at Montalvo. Conclusions — Santa Clara River Valley, Calleguas Creek Valley and Oxnard Plain The cheapest step in conservation of Santa Clara River Valley water would be construction of Montalvo spreading works. The next would be a pumping project in Santa Paula Basin and a conduit of 50 to 100 second-foot capacity to Pleasant Valley if investigation indicates that legal complications can be overcome. For present draft ]\[ontalvo spreading works would prevent marine intrusion into the pumping strata of Oxnard Plain with considerable margin of safety. Piru spreading works would raise the water table in Santa Clara River Valley and help the cjuality of water. They would benefit the possible future shortage in Oxnard Plain to an extent. Xothing more than the spreading works is believed necessary at present if their accomplishment is found to be as estimated but when aijd if the time arrives that water must be taken south, the size of the conduit and the comparative merits of creating additional underground storage space by pumping or creating surface storage space by construc- tion of a dam should be reviewed in the light of new information which will have been gained both as to the silt problem and other matters. When and if construction of reservoirs is undertaken. Cold Spring would be the first on the list because cheapest and Topa Topa would be next unless reconnaissance finds cheaper sites than those investi- gated. VENTURA COUNTY INVESTIGATION 27 PLAN 1. SURFACE RESERVOIRS Cold Si)ring Reservoir (conservation 8600 acre-feet) $l,!t20,0()0 Conduit of 200 second-feet capacity, diverting floods to Camarillo Kesei- voir when spreading works not operated (conservation 3400 acre- feet) and delivery fiom Cold Spring Reservoir direct to irrigated lands in years when available 1,:joi),(Mhi Camarillo Reservoir iSOS.OOU Total $4,028,000 PLAN 2. UNDERGROUND RESERVOIRS Created by Pumping (See Plate IV) tlra\ity diversion of rising water and pumping plant installation in lower end of Santa Clara Valley (conservation 12,000 acre-feet at least)__ $:171,000 Conduit of 75 second-feet delivering water by gravity to Pleasant Valley lands in all years 588,000 Camarillo Reservoir (not required) Total $954,000 Either of these plans could be used to deliver water by further puiiipinji' to Las Posas Valley. The comi)arison indicates that it would cost about four times as much to conserve 12,000 acre-feet by surface reservoirs as it would by creating new underground capacity in Santa Clara River Valley. Operating cost, however, would be higher for the latter, but not sut¥iciently higher to cause total annual cost of Plan 2 to approach that of Plan 1. The above two plans are independent of the spreading works noted in Table 2, but Plan 2 would decrease the water available to spreading works at Montalvo. Conclusions — Santa Clara River Valley, Calleguas Creek Valley and Oxnard Plain The cheapest step in conservation of Santa Clara River Valley water would be construction of Montalvo spreading works. The next would be a pumping project in Santa Paula Basin and a conduit of 50 to 100 second-foot capacity to Pleasant Valley if investigation indicates that legal complications can be overcome. For present draft IMontalvo spreading works would prevent marine intrusion into the pumping strata of Oxnard Plain with considerable margin of safety. Pirn spreading works would raise the water table in Santa Clara River Valley and help the quality of water. They would benefit the possible future shortage in Oxnard Plain to an extent. Nothing more than the spreading works is believed necessary at present if their accomplishment is found to be as estimated but when aijd if the time arrives that water must be taken south, the size of the conduit and the comparative merits of creating additional underground storage space by pumping or creating surface storage space by construc- tion of a dam should be reviewed in the light of new information which will have been gained both as to the silt problem and other matters. Wlien and if construction of reservoirs is undertaken, Cold Spring would be the first on the list because cheapest and Topa Topa would be next unless reconnaissance finds cheaper sites than those investi- gated. 28 DIVISION OF^ WATER RESOURCES Spreading- works and utilization of Santa Paula Basin would pro- vide during a period such as 1922-1932 an average of about 25,000 acre-feet annually of new water or perhaps more and it is possible by reservoir construction fo provide about 25,000 acre-feet in addition during' such a period bringing the total possible salvage to at least 50,000 acre-feet. Silt Prohlrin. The expense of co])ing with silt is an intangible item not considered in the foregoing costs. Silt disposal is a serious ])roblem in an attempt to conserve the waters of Ventura County as shown by the large amount of silt in water samples from streams col- lected by Santa Clara Conservation District. The comparative diffi- culties of the three available methods of conservation appear about as follows : 1. Natural silt dispf)sal would not be upset by pumping Santa Paula Basin and creating new storage capacity. The additional expense would therefore be nothing. 2. The spreading works proposed are designed to provide for dis- posal of silt from the Avorks to the stream bed whence it would find its way to the sea in subsequent floods. An item of additional expense Avould be incurred. 3. Xo way is known of disposing of silt from surface reservoirs. T'uless such means are found it would finally fill the reservoirs and destroy the investment. In ])roper accountinti- an amortization charge would be set up to care for this in addition to the amortization charge to retire the debt incurred by building the reservoir. Because of the large cost of the reservoirs it is believed such charge for silt deprecia- tion alone would be larger than annual expense of clearing silt from spreading works to say nothing of interest charge and the other amorti- zation charge just referred to. Ventura River Basin Two reservoir sites were investigated, the most economic capacities of which are as follows : TABLE 4 CONSERVATION BY RESERVOIRS, VENTURA RIVER BASIN Location Approxi- mately most economic capacity, acre-feet Average conservation 1922-1932, acre-feet Cost Name Total Per acre-foot of conservation Dunshee 7,400 10,000 2,000 5.300 •J780.000 2,550,000 $393 Mati'ija Ventura River 481 *Include.s conduit for diversion of Santa Ana Creek to re.servoir. The cost of a 25 second-foot conduit from ]\Iatilija Reservoir to Ojai Valley is estimated at $215,000. Conclusions — Ventura River Basin No construction is absolutely necessary at present for Ojai Valley but spreading works on the cones of the creeks tributary to it would VENTURA COI^XTY IXVESTIOATION' 2d raise the water table. Importation of water from Ventura River or Sespe Creek would involve such large cost that it seems impossible. The yield of the upper Ventura River Basin could probably be improved by pumping the basin and installing spreading works. The estimated cost of s])reading works is $142,000. No estimate of amounts of yield from the basin has been made. Before either installation of pumps or of spreading works the basin should be explored to determine capacity and depth to water table and the matter should be reviewed in the light of knowledge thus gained. The city of Ventura has four choices in the matter of water supply: (a) development of rpi)er Ventura River Basin as above noted; (b) construction of Dunshee Reservoir or other reservoir on Coyote Creek;* (c) pumping in the Lower Ventura River Basin below Casitas Road and near the ocean; (d) pumping at some point in the Coastal Plain southeast of the city. Costs for all these items have not been estimated but the estimate of Dunshee Reservoir indicates the probability that it would be by far the most expensive per acre-foot delivered. The first and the la.st involve certain legal complications. The silt problem previously discussed in connection with control of Santa Clara River would also be important on Ventura River and the foregoing discussion applies to it equally. CONFLICT WITH HIGHWAY ON PIRU CREEK The new state highway between Los Angeles and Bakersfield passes through Spring Creek and Los Alamos reservoir sites. As this is the second most important stream in Santa Clara River Basiii capable of conservation by surface reservoirs, question arises as to the damage suffered by Ventura County if the highway occupancy precludes use of these .sites for conservation of water. In the estimates of cost on which the following paragraphs are based no allowance was made for removal of highway from the above reservoir .sites so that the comparison is the same as though the highway were not constructed. Spreading works at Piru and Montalvo would give cheaper con- servation by far than the cheapest surface reservoir on Piru Creek. Likewise the reservoirs on Sespe Creek would be much cheaper per acre- foot of conservation than those on Piru Creek and would give a much greater amount of conservation. Furthermore, pumping in Santa Paula Basin to create additional capacity and to salvage a part of the estimated 12.000 acre-feet now being lost annually by willow growth would be cheai)er than any known surface reservoir either on Piru or Sespe Creek. The amount of conservation ultimately advisable is problematical at the time of this report. Economic limitations may be such that it will be impossible to supply all lands to the south which may eventually have a shortage in supply. It is probable that all cheaper conservation features will be adopted first and if so, no matter what the ultimate need, a reservoir on Piru Creek would be the last on the program and • A reservoir site exists on Coyote Creek a short distance above its junction with Ventura River. No surveys had been made of this by others at tlie time of this report. Before construction of a reservoir on Coyote Creek this site should be surveyed and foundation explored to determine its merits compared to Dunshee. 30 DIVISION OP WATER RESOURCES its necessity may be far in the future. Tlie future alone can deter- mine Avhether it will ever be neeessary and decision when made will rest on accumulation of knowled<>e between the present and the time of the decision. If decision is reaclied to add to conservation at that time by buiklin age, consists of sand- stone, shale and conglomerate. Its permeability is low and there are no water wells in this area producing directly from it. Deep wells drilled into structural depressions in this formation would probably produce large amounts of water. A well drilled by the Shell Oil Com- pany on an anticline near Santa Barbara developed a large quantity of water from it. The Topanga formation (Middle Miocene) consists of sandstones and conglomerates. In the vicinity of Newbury Park where the allu- vium is of small area and shallow depth the wells obtain their water indirectly from this formation, producing up to 25 miner's inches of water. The Mint Canyon formation, of Upper Miocene age, occurs from the vicinity of Mint Canyon eastward to the San Gabriel Mountains. It consists of interbedded conglomerate, sandstone and clay. "A study of the lithologic conditions of the Mint Canyon formation indicates that it must have been deposited under subaerial conditions. The region at that time was probably a large valley surrounded by moun- tains composed largely of granitic and metamorphic rocks and similar to large valleys in the southern California of today."* The formation is soft and gives rise to bad land topography. In general, the sandstone and conglomerate lenses are poorly consolidated and are relatively pervious. Many shallow water wells have been drilled into this formation and they produce small amounts of potable water. No large capacity wells are known in it. It is probable that dee*p wells in the formation would be good producers, especially if drilled in structural depressions. The Modelo formation, of Upper Miocene age, consists essentially of shale, with lenses of sandstone. Any water in contact with the shale is generally of poor quality, due to salts leached from it. The Modelo formation borders the Pirn Basin, and Pirn Creek flows for a great part of its course through it. According to Scofield,** the salt content of the water of Piru Creek, as measured by electrical con- ductance, is much higher than that of Sespe Creek. No water wells are known in the Modelo formation. In the area between Simi Valle,y and Newbury Park occur extrus- ives of andesite, basalt, dacite, tuff and breccia. The extrusives are in part vesicular and scoriaceous, and fractured. One well in Tierra Rejada, west of Simi Valley and east of Santa Rosa Valley, obtains its water directly from the igneous rocks. In the vicinity of Newbury Park some wells obtain their water indirectly from them. The Pico formation, of Lower Pliocene age, consists of interbedded sandstones, shales and conglomerates of marine origin. No water wells are known in the Pico formation. It is for the most part well con- solidated, forms bold outcrops, and ai)pears to be practically impervious to the movement of water. The Saugus formation, of Upi)er Pliocene and Lower Pleistocene age, consists of gravel, sand and silt, more or less unconsolidated. It varies greatly from place to place in lithology, degree of consolida- * Kew, W. S. W., Geology and Oil Resources of a part of Los Angeles and Ventura Counties, U. S. Geological Survey Bulletin 753, p. 53, 1924. ** Scofield, C. S., and Wilcox, L. V., Boron in Irrigation Waters, U. S. Depart- ment of Agriculture, Tech. Bulletin 264, p. 37, 1931. VENTURA COUNTY INVESTIGATION 37 tioii and pei-meability. Tcnvard tlie west tlif Sau^'us formation is of marine origin but it grades eastward into sti-ata of fiuviatile origin or alluvial fan deposits. "The physical characteristics are unmis- takably those of an alluvial deposit, a river delta, progressively sink- ing."* The gravels are lenticular and have a sand matrix with little argillaceous cement. Locally, there is some calcareous cement. In the canyons tributary to the Santa Clara River in the region from the Los Angeles-Ventura County line to a point a few miles east of Saugus there are many shallow wells drilled in the Saugus formation which furnish small amounts of potable water. North of the city of Ventura the Shell Oil Company drilled a deep well into the Saugus formation capable of producing 200 inches of water. Many, of the commercial wells in the vicinity of Camarillo and Oxnard produce from this formation. Wells of the Tapo Mutual Irrigation Company in Ta])o Canyon, north of Santa Susana, also produce from it. The terrace deposits, of late Pleistocene age, are chiefly poorly consolidated gravels and sands and clays of terrestrial origin, laid down as flood plains or alluvial fans. They all exhibit a reddish color due to oxidation. They occur as almost flat-lying remnants on ridges or sides of the valleys, as on the ridge between Dry Canyon and Haskell Canyon, and also as deposits gently sloping from the hills toward the valleys partially overlain by recent alluvium, as in the area at Saugus. Several distinct terrace levels may be seen on the eastern side of Castaic Valley north of Castaic Junction. The present terraces are the remnants of originally broader deposits. The terrace deposits are, generally speaking, permeable, and their importance as underground reservoirs depends on the local structure. Naturally, where these deposits occur as caps on ridges they can not long hold water. The recent alluvium is confined to the lowest portions of the valleys. It represents a recent period of deposition following the earlier period when the streams eroded their channels in the older formations. It is loose and uncemented. In the Santa Clara River Valley the alluvium is chiefly gravel, forming a broad, flat deposit in the valley bottom. The surface of the gravel is covered with gray sand, hardened in places by fine silt. Although sand predominates at the surface of the Santa Clara River bed, gravel predominates below the surface, as shown by well logs. It is probable that the surface sand is carried away by the winter floods and gravel deposited in its place. Then, as the flow subsides, sand is deposited on the gravel, and finally silt. Most of the streams of the area are now entrenched in channels in the alluvium. This is not true throughout the length of Santa Clara River but applies chiefly to tributary streams. West of Lang the bed of Santa Clara River is dry during most of the year, except for areas near Castaic, Piru and Santa Paula where there is rising water throughout the year which supports a dense growth of willoAvs. The character of the alluvium varies according to locality, from the coarse, porous sands and gravels in Santa Clara River Valley * Her.shoy, O. H., American Geologi.st, V. 29, pp. 359-362, 1902. 38 DIVISION OF WATER RESOURCES to tigliter, more clayey deposits formed by tributary streams and by run-off from the sediments of the hills bordering the valley. Santa Clara River, rising in an area of granitic and metamorphic rocks, and flowing through the gravelly deposits of the Mint Canyon and Saugus formations, has deposited relatively clean, porous alluvium. In Ojai Valley, granitic boulders are absent. The alluvium is chiefly sandstone boulders with more or less angular fragments of slaty shale. Areal Geology Geological maps of part of the area covered in the report have been published. The maps in U. S. Geological Survey Bulletin No. 753* cover the area to the east of the Santa Paula, Quadrangle. A sketch map of the geology of a portion of the Ventura Quadrangle is included in Volume 12 of the Bulletin of the American Association of Petroleum Geologists.** The geologic maps (Plates LI to LIII) in rear pocket, accompany- ing this report, are based partly on the IT. S. Geological Survey maps above noted and partly on information obtained from Dr. Eliot Black- welder, Mr. Claude Leach and others. On these maps the formations are grouped according to their importance as water yielding forma- tions. The groups are as follows : (1) The Recent Alluvium, Avhich occupies the valleys and from which most of the commercial wells obtain their water. (2) The Terrace Deposits (Pleistocene), which are, in general, permeable, and whose importance depends on structure. Many commercial wells produce from the Terrace Deposits. (3) The Saugus formation (Upper Pliocene and Lower Pleisto- cene) and the Mint Canyon formation (Upper Miocene), which produce domestic supplies from shallow wells and larger supplies from deep wells. The aquifers in this group are usually confined and the water is under pressure. (4) All the other, less pervious, formations. RELATION OF THE TERTIARY FORMATIONS TO THE ALLUVIAL BASINS Eastern Basin The large area of alluvium to the east of the Ventura-Los Angeles County line is referred to as the Eastern Basin. In this basin there is a broad area of terrace gravels bordering and in places underlying the alluvium. As the few wells in the basin are located within a narrow belt in the alluvium, there is no lateral control for estimating water levels, upon which change in storage computations depend. Hence no attempt was made to compute changes in storage in the Eastern Basin. The alluvium and terrace gravels comprising this basin are bordered on all sides and underlain by the semipervious sediments of the Saugus and Mint Canyon formations, which are both of continental origin and are the most permeable of the sediments older than the • Kew, W. S. "W., op. cit. ** Cartwright, Lon D., Jr., Sedimentation of the Pico formation in the Ventura quadrangle, Calif., Am. Assoc. Petroleum Geologists, Bull., V. 12, No. 3, Jan. 1928. VENTURA COUNTY INVESTIGATION . 39 terrace gravels. Both formations contain streaks and lenses of poorly- consolidated sand and gravel capable or producing water of good quality. Shallow wells drilled into them yield domestic supplies of water. The depth to water measurements made during the course of the general investigation were confined to the wells drilled in the main valley bottoms as all the commercial wells occur in them. Records of depth to water were obtained for scattered wells drilled in the Mint Canyon formation in the vicinity of IMint Canyon and Plum Canyon. These wells showed very little fluctuation of water level. Information from owners of wells drilled in the Saugus formation in the area northwest of Castaic indicated that there was very little fluctuation of water level in this formation. The stable water level over long periods of time is no doubt due to the small number of wells drilled into the Saugus and j\Iint Canyon formations in comparison to their large area. As the recent alluvium and terrace gravels comprising the Eastern Basin are bordered and underlain by the semiporous Saugus and Mint Canyon formations, the important question arises: "Do these older sediments constitute an integral part of the main underground allu- vial water basins?" To do so, there must be a direct connection betAveen the water bearing strata of these formations with the recent alluvium, so that a lowering of the water plane in the alluvium will cause a transfer of water between them and result in a corresponding lowering of the water level in the Saugus and ]\Iint Canyon formations. In the Eastern Basin, this transfer of water does not appear to take place. Wells in the alluvium of the Santa Clara River Valley from Mint Canyon east are pumped dry in the summer months. The wells in the Mint Canyon formation do not reflect this lowering of water level. The water level in a well drilled on the ridge between Mint Canyon and Soledad Canyon, in the Mint Canyon formation, was, when measured, 200 feet higher than the water level in the alluvium of Soledad Canyon, only 3500 feet distant. One element preventing direct connection of the water yielding beds of the Saugus and ]\Iint Canyon formations wnth the alluvial basins is folding. The older formations are warped and dip under the alluvial basins, and impervious strata interbedded Avith the more pervious sands and gravels prevent migration of water into the alluvium. In the Eastern Basin there are really two basins, first, the alluvial basin, and, second, the basin composed of Saugus and Mint Can^'on sediments which borders and underlies the alluvial basin. It is pos- sible that deep wells drilled through the alluvium, well into either the Saugus or Mint Canyon formations, and perforated only in these latter formations, would produce large quantities of water. No wells of this type are known in the Eastern Basin. Under similar geologic condi- tions, the well previously referred to drilled by the Shell Oil Company through the alluvium of the Ventura River a short distance north of the city of Ventura produces from the Saugus formation about 200 inches of water. The Saugus and Mint Canyon formations undoubtedly^ contribute some water by underflow to many of the alluvial basins. This contribu- tion is at a more or less constant i-ate throughout the vear and the rate 40 ' DIVISION OP WATER RESOURCES is not appreciably increased by loAverini-e area of pervious tei-raee deposits on tlie north side of tlie basin. The northern boundary of the basin is the contact of the alluvium or terrace deposits with the impervious Pico, Modelo and T(\ion formations and, near tlie exti-eme western end, with tlie Sang'us formation. The alluvium of the basin is in contact on the south with Ihe relatively impervious Modelo, Vaqueros and Sespe formations of Oak Rido-e. The western boundary of the basin is arbitrary and is based neither on <>eolo«iic structure nor a steepening of the water plane. It approxi- mates the eastern limit of the area of rising water which supports the dense growth of willows in the Santa Clara River east of Willard Bridge. There is some indication of a fault extending almost due west from the south side of the valley at the Piru-Fillmore Basin boundary to well number 15-N-8 (Plate XLIX in rear pocket) about four and one- h df miles to the west. The presence of the fault is indicated chiefly by water levels. Some wells to the north of this supposed fault flow. Santa Paula Basin Santa Paula Basin on its eastern end, adjoins Fillmore Basin. Its southern boundary is the contact of the alluvium with the relatively impervious sediments of South Mountain, namely, the Pico, Modelo, Vaqueros and Sespe formations. The northern boundary is approxi- mately the contact of the alluvium or terrace deposits with the Saugus formation. A well drilled for the Blanchard Investment Company in Fagan Canyon, northwest of the city of Santa Paula, penetrates and draws its water from the Saugus formation, yet its water level fluctu- ates with the water level in the alluvium. There are not enough wells to the north of the alluvium-Saugus contact to determine how far north the water level in the Saugus formation reflects the fluctuation of water level in the alluvium. In computing the change in storage, only the area of alluvium and terrace deposits was considered. The western basin boundary is a definite, devious line separating the higher water level of Santa Paula Basin from the lower water level of Oxnard Plain. The barrier sei^arating these two water levels is believed to be due partially to faulting and partially to a subsurface fold in the Tertiary sediments. The alluvium and terrace deposits of Santa Paula Basin are under- lain by the Saugus formation which crops out on the northern side of the valley. (See Plate LIII in rear pocket.) Oxnard Plain Nonpressure Area The Oxnard Plain nonpressure area occupies the upper portion of the Santa Clara River alluvial fan. The alluvium is bounded on the north along the foothills by the Saugus formation, and by Santa Paula Basin. The eastern boundary is the eastern limit of the Santa Clara River fan and is approximately a line connecting the western end of South Mountain with the western end of Camarillo Hills. The southwestern boundary was determined by a study of the well records. Those wells the water level of Avhich rose rapidly at the end of the puminng season were included in the pressure area. Wells, the water level of wliieli showed no rajjid I'ise, were included in Ihe nonpressure area. 42 DIVISION OF WATER RESOURCES The Oxnard Plain nonpressure area is underlain by the Saugus formation. Anomalies in water level indicate that some of the wells obtain their water from the Saugus formation but most of the water pumped is from the alluvium. There may be a slow, steady contribu- tion of water from the Saugus formation to the alluvium, but this quantity can not be actually measured. Oxnard Plain Pressure Area The Oxnard Plain pressure area occupies the Santa Clara River flood plain between the nonpressure area and the Pacific Ocean. In this area occurs perched water and deeper artesian water, separated by clay beds. The depth to the upper surface of the Saugus formation varies from zero at the western end of Camarillo Hills to approximately 1300 feet. It is not a smooth surface but shows ridges and valleys extending in a general northwest-southeast direction, governed by the structural lines of the region. Overlying the Saugus formation occur the Pleistocene and recent deposits transported chiefly by Santa Clara River and deposited under estuarine conditions. The sorting action of waves in the shallow embayment accounts for the clay beds overlying the coarser, permeable sands and gravels. Small tidal lagoons and marshes still exist along the coast. Many of the wells in the Oxnard Plain pressure area are known to produce from the Saugus formation, although there is no great difference in water level between deeper and shallower wells. This may be due to the practice of perforating the casing to produce from both the alluvium and the underlj-ing Saugus formation. Simi Valley The Simi Valley Basin occupies a depression" to the south of Oak Ridge and west of the Santa Susana Mountains. The two towns of Simi and Santa Susana are located in the basin. The alluvium of the basin is, on the south and east, in contact with resistant Eocene sand- stone, on the north with standstone and clay of the Sespe formation, and on the west bj^ the Sespe formation and by Miocene extrusive and intrusive igneous rocks. (See Plate LI in rear pocket.) There are no large streams flowing into Simi Basin. The ground- water is an accumulation over a long period of rainfall on the small watershed. There is very little real gravel in the alluvium of Simi Valley. This is because the alluvium was derived from an area of sedimentary rocks which break down by mechanical disintegration into their con- stituent grains resulting in fine sand chiefly, and silt and clay. What gravel lenses there are were derived by a reworking of the gravels of the Saugus formation and the terrace deposits. A large number of wells in Simi Basin are drilled through the alluvium into the under- lying Sespe or Eocene formations. At the northwestern end of Simi Valley there is a small pressure area in the alluvium. Although the static water level is above the ground surface, the water level rapidly lowers in the wells when pumped. For instance, the water level in wells numbers 20-R-l and 20-R-18 (see Plate XLIX in rear pocket) lowers 150 feet when pump- VENTURA COUNTY INVESTIGATION 43 iiig 25 iiiclies of water, although their static level is above the ground surface. As shown by the rapid drawdown of wells in it, the alluvium at tlie lower end of the basin is very tight and there is little underflow out of the basin through it. Also, a well was drilled just south of well number 20-R-18 to a depth of 264 feet and produced no water. There is a small flow of rising water at the lower end of Simi Basin due apparently to a slow upward migration of water through the tight, clayey alluvium. Flowing wells drilled in this area may be accounted for on the theory that they allow the water to reach its static level without having to overcome the friction of the alluvium. The channel leading out of Simi Valley varies from 65 to 85 feet in depth and well logs show that a shallow lake existed at the lower end. This lake was gradually filled with vegetation and covered with silt and clay. Water evaporating from this marshy area resulted in a concentration of salts, so that the water in wells in the lower end of Simi Valley is of very poor quality. Evaporation of rising water is still increasing the mineral concentration, and there is not enough sur- face flow or underflow to wash this concentration out of the tight alluvium. In general, ground water on the south side of Simi Valley is of good quality and is better than that on the north side of the valley. Water entering the basin from the south flows over and through crevices in the cemented Eocene rocks and does not pick up enough minerals from the rocks to seriously affect the water. The small streams which enter Simi Valley from the north rise in areas of Modelo shale or the Sespe formation, and leach out salts from them, chiefly from the former. Also, there are a number of old oil wells to the north of Simi Basin and it is believed that waste water from these wells is a contributing factor to the poorer quality of water on the north side of the valley. In the Sespe formation exposed on the north side of Simi Valley there are some springs of good quality water north of the oil weUs. The springs south and west of the oil wells, and down the slope from them, are of poor quality. These wells are producing highly mineral- ized water which eventually finds its way into the alluvium. This oil well waste water accounts for the extremely bad water in well number 19-Q-2. North of Santa Susana, in Tapo Canyon, several wells of the Tapo Mutual Water Company are producing directly from the Saugus formation. The water contains some sulphur but is of good quality for irrigation. Here the controlling factor is structure. Plate LIII in rear pocket shows a geologic section up Tapo Canyon across the synclinal structure in which the underground water is stored. Many of the wells in Simi Valley produce from the Tertiary sedi- ments which underlie the alluvium in which the water is under pressure. The actual change in storage for such wells takes place around the margins of the basin outside of the alluvium. Las Posas Valley The Las Posas Valley extends from a line connecting the western end of South Mountain with the western end of the Camarillo Hills to the lower end of Simi Valley. As the groundwater conditions are 44 DR'ISTOX OF WATER RESOURCES different in tlie eastern half of the valley tlian in the western half, the two sections will be discussed separately. The eastern half of the valley, from the vicinity of Somis east to ^Ioor])ai'k, is an area of alluvinni nnderlain by terrace deposits which are in turn nnderlain by the Saiigus formation. Wells drilled in this area produce from all of these formations. The quality of the water is in general far better than the water at the lower end of Simi Valley. The water is obtained by underflow from the large area of terrace deposits and pervious Saugus gravels to the north. The eastern half of Las Posas Valley occupies a structural trough, as shoAvn on Plate LIII in rear pocket. The western half of Las Posas Valley, namely, the area between Camarillo Hills and xSouth Mountain is also an area of alluvium, ter- race deposits and Saugus formation, but these formations in this area are tight. North of the eastern half of Las Posas Valley, in the vicinity of Epworth, there are several wells of good quality water and good rate of production. These wells are drilled in the terrace deposits and Saugus formation, which in this area, is very pervious. Good exposures of loose porous sands and gravels of the Saugus formation may be seen along the Grimes Canyon Road northwest of Epworth. (See Plate LI in rear pocket.) The recharge for the Epworth area is dependent on the penetration of rainfall on the large area of pervious sands and gravels of the terrace deposits and Saugus formation. Pleasant Valley Pleasant Vaile.y lies south of Camarillo Hills, north of the Santa Monica Mountains and to the northeast of the Oxnard Plain pressure area. Well logs in this area show that there is very little gravel in the upper 400 feet. Wells vary from 400 to 1500 feet in depth. The water is under pressure and different wells exhibit different water levels. The production is chiefly from the Saugus formation. Santa Rosa Valley Santa Rosa Valley lies just south of the Las Posas Hills. H is a valley of alluvium and terrace deposits bordered on the south by igneous extrusives and intrusives. The alluvium and terrace deposits are underlain by a few hundred feet of the Saugus formation which is, in turn, underlain by the Sespe formation. Wells drilled in the alluvium and terrace deposits are very good, producing up to 150 inches of water of good quality, and the water level holds up remark- ably well. There is no large surface inflow of water to the basin and it obtains its recharge by rainfall penetration on the alluvium and terrace deposits within the basin and by underflow chiefly from the igneous rocks to the south. That these andesitic breccias and scoriace- ous and fractured basalt are pervious is shown by a well drilled in Tierra Rejada, to the east of Santa Rosa Valley. This well was drilled to a depth of 400 feet, practically all of which was through the "]\Ialapai formation full of wormholes, " which is the vesicular and scoriaceous andesite and basalt. No gravel was encountered. The well produces about 80 inches of good water. VENTURA COITXTY INVKS'lKiAlIOX 45 A well was drilled into the Saiii"id«>e to Cavin Road. -8367—8375 50 DIVISION OF WATER RESOURCES PLATE V 10,000 c o u TO o ■OO Q 10.000 1.000 100 1 M 1 ' M ! 1 1 ! 11 1 -l-±-\ L^M_4-U-i-l- ' 1 -f- PERCOLATION IN SECOND-FEET SANTA CLARA RIVER CAVIN ROAD TO MOUTH OF SESPE CREEK FROM MEASUREMENTS 1 / - / - - / - - / / - - ( - 1 1 f t 1 f 1 - i - - / - - '\ - - / / - y / / o ft. OO -o >> -OO 1i '0 •OO o 1 1 1 ' I 1 1 1 M 1 1 1 1 1 1 1 II 1 1 i 1 1 II 1 1 1 1 1 1 1 1 1 1 I F 'ERCOLATION IN SECOND-FEET HOPPER CREEK HIGHWAY BRIDGE TO CAVIN ROAD FROM MEASUREMENTS f t t / / - - / / - - 4 / / / / - / f / - / / - - / - - i / f - - / / / / - * / / / 4 - / - - - J A' o 1931-1932 - / / 1 .,i .. 1— _L_ 1 _1 . - I 10 Percolation in second-feet 100 VENTURA COUNTY INVESTIGATION 55 PLATE X 10,000 2^ 1.000 0) ^- i ■a c o o a> 0) oo CD -C OO 0) 1- x: o V) Q 100 10 1 I 1 1 1 1 1 i 1 1 1 f - i - \ r - 1 / - - 1 / / - / / / r - / - - / - - / / f - - / / / / - ° J* jr^ ^ ° Ao o T° / - y - - / / - - / / - -/ / 1931-1932 - f' - PERCOLATIC SE. MOUTH OF CAN FRC )N IN SECOND-FE 5PE CREEK YON TO HIGHWAY BRIDG )M MEASUREMENTS ET E - J .-L.. -JL. 1 L_ 1 _L 1 10 100 Percolation in second-feet 56 DIVISION OF WATER RESOURCES PI.ATE XI un-off at Newhall Ranch Bridge in acre-feet i § § 1 1 '., ' 1 1 T-'-r ■ ' 1 ' 1 UPiKJUl v Drn/*Ai ATiriM w 1 A/»Pir r L rrr " WUnmLi ri:nv,WLMi lUiN IIM AV-«L r SANTA CLARA RIVER NEWHAI 1 R&NTH RRIDfXF Tn TriDDFv on EET * /- - / - - / / - / / i / - y Vm - IL _ - / - - / - - ^ - -/ /- - / _ - / - - / - ~ / - c o 10 - n - , / - 3 / - ^ _J_ _1__L 1 1 _I__L 1 , , , - 10 100 1,000 10,000 Monthly percolation in acre-feet VENTURA COUNTY INVESTIGATION 57 PLATE XII 100,000 "3 1 0,000 c o en >. Kooo >) 1 1 -r 1 1 1 1 7 /- / 1 _ _ 1 MONTHLY PERCOLATION IN ACRE FEET SANTA CLARA RIVER TORREY ROAD TO CAVIN ROAD / / - / - - / - - / - - / - 1 / z / ^^ / J r \r_ - / / - - / / - - /> / - - / y^^Percolation a / / major floods fter - _A J* 1 t / 2^ // O - ^ / - - A y - - y // - - / - , ' J 7 / - / - - / - - / - / __i_ 1 1 ._!._ J_ 1 IL _L 1 1 i_ 100 1.000 10,000 Monthly percolation in acre-feet 58 DIVISION OF WATER RESOURCES PLATE XIII 100,000 0,000 T3 O CH > o 1.000 c 00 1 1 i 1 1 """ T 1 1 1 1 ' 1 -U-i i / - MONTHLY PERCOLATION IN ACRE FEET SANTA CLARA RIVER / CAVIN ROAD TO MOUTH OF SESPE CREEK / — - / - — — - - - - - - - / / - zx a TL / / / - / - - / - - / > - J C — — r Z^ 7 - / - - / / - _> / - A 1 1 1 1 1 1 1 _L, , 1 100 1,000 Monthly percolation in acre-feet VENTURA COUNTY INVESTIGATION 59 PLATE XIV 100,000 (V '^ 10.000 c ■o \_ CD >% o CO -t-» c 1,000 100 ' 1 1 M M 1 1 1 1 1 1 I 1 1 1 1 1 1 1 M 1 1 1 1 1 ' A - MONTHLY PERCOLATION IN ACRE-FEET SANTA CLARA RIVER IN VICINITY OF SATICOY / / / 1 1 / — /- — (- / / - ' < - - / / / 1 - - / / 1 1 - - // - / / / / * / / f / ,' - / f - - / > 1 - - / 1 - - / ( f / / - / / / / f , / From Saticoy Bridge to Montalvo Bridge- / t - / - - / / f / - - / / C •om i 3. inl 5an take ta ; t Clara Mo Water and ntalvo brie Irri^ s - A f 4 / ,' / f > / - / • - - / • f - . - i L_ _i_ .._i_ i - 10 100 ,000 Monthly percolation in acre-feet 60 DIVISION OF WATER RESOURCES PLATE XV 100.000 10.000 cu ID $ 1.000 2^ 100 1 1 11 ■ ' 1 < 1 1 1 ! : : 1 1 1 1 1 r i : 1 1 1 i { { : 1 1 i 1 1 ■ 1 ' 1 I'll ' 1 1 - ' ' ; ■ 1 1 1 1 i- - MONTHLY PERCOLATION IN ACRE-FEET PIRU CREEK HIGHWAY BRIDGE TO TORREY ROAD ! 1 '~ - / — / - / ■ : 1 ' 1 1 1 1 1 1 \ 1 1 ' i i i 1 ! i j ! 1 ^ - 1 1 i 1 / ^ - i / - > / : J 1 - 1 / / - — H — 1 ~H" "^ ' — -T 1 \A yf^ 1 ! > ' 1 t — i !/| A - ! /;l - - y 1 1 1 |: - ~ / / i - I 1 / 1 . 1 1 / 1 1 1 - 1 >^ I — _ 1 /( - - / - -/ ^ 1 I 1 1 1 1 1 1 I 1 , 1 1 10 100 1000 Monthly percolation in acre -feet VENTURA COUNTY INVESTIGATION 61 PI.ATR XVI Monthly run-off at Highway Brid6e in acre-feet — o - o b — o o o o o o o ' ; ' 1 ■ 1 ' 1 1 M i 1 ' 1 1 1 ' I N I- 1 J-H - ' -U-^ MONTHLY PERCOLATION IN ACRE FEET HOPPER CREEK HIGHWAY BRIDGE TO CAVIN ROAD — — -l~ -- c. / - y y - / - V - - / j / 1 / / / / - / - - y f - - / - - / / - 1 / / / / - / - - / - - / - - / / - / / / / - / - / - / - / I _ .1 1 1 - 10 100 1,000 Monthly percolation in acre-feet 62 DIVISION OF WATER RESOURCES The season 1931-32 was the only year when discharge from the canyon mouth of Ventura River was sufficiently sustained to measure percolation. The losses are shown in Table 7. TABLE 7 PERCOLATION IN UPPER VENTURA RIVER VALLEY, AVERAGE SECOND-FEET Period Discharge At Matilija Ranch Intake Loss Discharge At Meyer Road Crossing Loss Discharge At Oakview Road Crossing Gain Discharge At Ventura City Intake Total loss, Matilija to Oakview January 3 to 7. 1932— 5 days 38.9 105.0 123 45.9 5.9 2.0 3.0 2.9 33.0 103.0 120.0 43.0 28 1 9.0 4.0 3.8 4.9 94.0 116.0 39.2 7 3 23.0 42.0 20.7 12.2 117.0 158.0 59.7 34.0 February 3 to 6, 1932— 4 days . 11 2 February 15 to 29, 1932— 7 8 March 1 to 31. 1932— 31 days 6.7 Distance between points in miles Total distance, Matilija Ranch to Oakview Road. Note.— Percolation also occurs immediately below Oakview Crossing and above the rim of rising water. Measurements were not taken on this. In addition to the locations shown, measurements were taken at Burnham Road between Meyer Road and Oakview which indicated a gain between Meyer Road and Burnham Road for a portion of the period, although the net loss from Meyer Road to Oakview still was consistent with prior and subsequent measurements. For this reason discharges at Burnham Road are not given as it is believed these measurements do not show true conditions. Deep Percolation from Rainfall on Valley Floor The method of estimating this is given in Chapter VI. By the method thus developed, the percolation for each storm during the period of investigation was calculated for each basin. The information thus developed was used to construct generalized curves by which the percolation by months during the 40-year period was estimated from rainfall records. This is not a large source of supply to the under- ground basin of Santa Clara Valley, being estimated at 20 per cent of the total. For Calleguas Creek the supply is smaller, as the rain- fall is less, but is believed to be larger than the contribution from streams. Underground Contribution from Porous Hills and Mountains This is a small amount in Santa Clara Valley or the basin of Ventura River, but is probably the major source of supply in the basins of Calleguas Creek. As it is a small item in the total supply in Santa Clara Valley it was neglected. No attempt to calculate it was made for Calleguas Creek Basin. Storage Capacity in Valley Fill This is estimated as described in Chapter V. VESNTURA COUNTY INVESTIGATION 63 Underground Flow This refers to the uiideifiround flow from an upper into the next lower basin. No wholly satisfactory method of arriving at this is known. For this analysis, it was accepted that any quantity remaining after all contributions to and drafts on a basin had been evaluated was inflow underground if the residual quantity was plus and outflow if it was minus. This throws all error into the quantity. The quanti- ties thus determined for each year were used to plat a curve of outflow as compared to water table elevation, as obviously the outflow must increase as the water table rises unless there are unusual conditions not found in any basins studied. Consumption by Water-loving Plants Where the water table is close to the surface will be found a growth of willows, etc. These cover 3670 acres in Santa Clara Valley and about 150 acres in Ventura River Basin above Casitas Road but the area is negligible in Calleguas Creek Basin. From other work it is esti- mated the willows of Santa Clara Valley consume 34 inches of water in depth per acre in the seven months from November to ^larch, inclu- sive, and a total of 40 inches in depth per year per acre, causing a total loss from groundwater of 11,700 acre-feet per year and 500 acre-feet from rainfall which would have penetrated to the water table if they had not been present. This loss was proportioned in accordance with area covered by such vegetation as measured during the investigation. In Ventura River Basin the type of water-loving vegetation consumes 4.0 feet in depth annually, from determinations elsewhere.* Irrigation Exportations This refers to the exportation from one basin for use in another. Records were secured during the investigation. Use by Irrigated Lands In the Oxnard Plain where there is an impenetrable clay cap between the ground surface and the pumping strata and in Pleasant Valley where wells draw from the Saugus formation, percolation from irrigated land can not return to the source and consequently the use is the total water pumped. The surplus is drained into the ocean artificially. In Santa Clara Valley, Ojai Basin, Ventura Basin and the basins of Calleguas Creek other than Pleasant Valley, this surplus percolates again to the water table and is reused. In such cases the total use by each irrigated area is the water actually consumed by the plants and incidental evaporation and not the amount pumped. This consumptive use is smaller than the water applied. The values used for this analvsis are as shown bv the following table. • Bulletin 44, "WTater liosses Under Natural Conditions from Wet Areas in Southern California," South Coastal Basin Investig'ation, Division of Water Resources. 64 DIVISION OF WATER RESOURCES TABLE 8 ASSUMED CONSUMPTIVE USE OF WATER FOR IRRIGATION Acre- feet per acre Piru Basin 1.45 Fillmore Basin 1.33 Santa Paula Basin 1.15 Oxnard Plain *0.90 Las Posas Valley 1.24 Simi Valley _.. 1.21 Santa Rosa Valley 1.30 Pleasant Valley '1.10 Ojai Basin Not estimated Ventura River Basin. __ .Not estimated • Total use. CHAPTER V BASIN CAPACITIES— METHOD OF COMPUTING SPECIFIC YIELD The terms "srroiuid water storage" and "storage capacity" as here used refer to the volume of the open voids or interstices available for the storage of water which can be entirely recovered. They do not include the volume occupied by water which can not be recovered due to the forces of adhesion and cohesion which give rise to the retention of water as films and in capillary openings. Quoting Meinzer:* "The specific yield of a rock or soil is the per- centage of its total volume that is occupied by gravity ground water, and the specific retention is the percentage of its total volume that is occu- pied by water which is not gravity ground water and which it will not yield to wells. Thus, the specific yield and the specific retention of a rock or soil are together equal to its porosity. If a rock has a specific yield of 8 per cent and a specific retention of 13 per cent its porosity is obviously 21 per cent. The specific yield of an impermeable rock is zero, its specific retention being equal to its porosity. ' ' The terms "ground water storage" and "storage capacity" are the volumetric equivalents in acre-feet of the specific yield in per cent. For computing storage capacity or change in storage the five min- ute lines of latitude and longitude are shown on U. S. Geological Survey maps of the region and w^ere divided into 10 equal parts, result- ing in a grid of areas one-half minute of latitude by one-half minute of longitude. Each covers an area of 174.7 to 175.8 acres** and an average of 175 acres was used in computations. Groups of well logs were averaged and specific yield values com- puted for intervals of 50 feet in depth below the ground surface. POROSITY, SPECIFIC RETENTION AND SPECIFIC YIELD Sand and Gravel Samples from Santa Clara River Valley Methods followed were those developed in South Coastal Basin Investigation of the Division of ^\"ater Resources.*** Sixteen samples were taken of sand and gravel in the Santa Clara River Valley to determine the porosity, specific retention and specific yield. At the location for digging the sample, the ground surface was cleared of soil and leveled. A hole was dug, as small in area as pos- sible at the top and widening with depth. All of the excavated mate- * Meinzer, O. E., The Occurrences of Ground Water in the United States U. S. Geological Survey Bulletin 489, p. 51, 1923. ** Ganett, S. S., Geographic Tables and Formulas, U. S. Geological Survey Bulletin 650, p. 120, 1916. *** Bulletin No. 45, Division of Water Resources, South Coastal Basin Investi- gation, "Geology and Ground Water Storage Capacity of Valley Fill." 5 — 8367 — 8375 ( 65 ) 66 DIVISION OF WATER RESOURCES rial was ])laced in sacks to be analyzed at the laboratory in Claremont maintained cooperatively b>' the Division of AVater Resources by arrangement with Pomona College. The volume of the sediments exca- vated was determined by filling the holes with a measured volume of sand of uniform grain size. The sand was poured from a receptacle into the measuring can or graduate without packing and poured into the hole in the same manner and from the same height, in order that the sand when in the hole would occupy the same volume as it did in the measuring device. At the laboratory, the samples were screened to segregate the con- stituent grains into the following grade sizes : Over 512 millimeters ; 256 to 512 mm. ; 128 to 256 mm. ; 64 to 128 mm. ; 32 to 64 mm. ; 16 to 32 mm. ; 8 to 16 mm. ; less than 8 millimeters. The volume of the grade sizes over 8 millimeters was determined by submerging the particles in water and measuring the volume of the water displaced. The particles under 8 millimeters in diameter were separated by screens shaken mechanically into the following grade sizes: 4 to 8 mm.; 2 to 4 mm.; 1 to 2 mm. ; I to 1 mm. ; i to ^ mm. ; and less than ^ mm. The volume of the various grade sizes under 8 millimeters in diameter was deter- mined by dividing the dry weight by the specific gravity. Specific gravity determinations were not made on the samples, but a value of 2.68 was used, as this is the average specific gravity of a number of samples from stream cones in the South Coastal Basin as determined in the Claremont laboratory. The total volume of the solid aggregate sub- tracted from the measured volume of the hole gave the volume of pore space in the gravel as it existed in the field. The specific retention of the sample was estimated from its mechan- ical analysis.* The porosity in per cent minus the specific retention in per cent gave the specific jdeld in per cent. Location of Samples The locations of the samples are given below. The sample num- bers in parentheses are the sample numbers in Bulletin No. 45. Sample No. 2, (G-125). Gravel sample from Kellerman pit, about 200 feet east of Torrey Road and 50 feet south of Howe Road. Depth of sample 103 feet to 105 feet, underlain by a clay streak and overlain by several feet of clean gravel. Sample No. 4, (G-127). Gravel sample from 100 feet west of Highway No. 99 at north end of Pico Creek Bridge, from a bench about three feet above the present stream bed. Sample No. 5, (G-128). Gravel sample from 150 feet north of sample No. 4, in the same gravel deposit. Sample No. 6, (G-129). Gravel sample from 150 feet east of Bou- quet Canyon Road and 200 feet south of the south end of the Santa Clara River Bridge, from bench about 10 feet above the present river bed. The gravel was loose and caved readily. A large sample was taken because of the large size of the top opening (approximately 8 by 14 inches) and because of sporadic boulders up to seven inches. * Bulletin No. 45, siipi'a. VENTURA COUNTY INVESTIGATION 67 Sample Xo. 7, (G-13()). Gravel sample from west side of gravel pit, ai)proximately 100 feet soiitlnvest of the Los Angeles aqueduct and 1200 feet nort invest of Mint Canyon Road. Sample No. 8, (G-131). Gravel sample from gravel pit east of Piru Creek and south of the highway. Sample No. 9, (G-132). Gravel sample from 500 feet south of the Santa Clara River crossing southwest of Lang, from bench about three feet above the present river bed. Sample No. 10, (G-133). Gravel sample from five feet north of sample No. 9. Sample No. 12, (G-135). Sand sample from 2000 feet east of the south end of Saticoy Bridge over the Santa Clara River. Sample No. 13, (G-136). Sand sample three feet from sample Xo. 12. Sample No. 14, (G-137). Sand sample from 1500 feet west of the middle of Fillmore Bridge over the Santa Clara River. Sample No. 15, (G-138). Sand sample 10 feet from sample No. 14. Sample No. 16, ,(G-139). Gravel sample 10 feet from sample No. 15. Sample No. 17, (G-140). Gravel sample five feet from sample No. 16. Sample No. 18, (G-141). Coarse sand and fine gravel from 300 feet north of the south bank of the Santa Clara River and 50 feet west of Torrey Road. Sample No. 19, (G-142). Sand sample from 25 feet north of sample No. 18. Mechanical Analyses Of these samples, numbers 12, 13, 14 and 15 were sand samples. Number 13 was a tight, well indurated, rather dirty sand. Its porosity was 36.5 per cent and its specific yield 24.8 per cent. The average for the other three clean river sands was 41.8 per cent porosity and 31.4 per cent specific yield. Samples numbers 18 and 19 were of coarse sand and fine gravel. Their average porosity was 37.6 per cent and their average specific j'ield 31.7 per cent. The other ten samples were of gravel. Of these, numbers 2, 8, 16 and 17 w^ere of clean, unaltered gravels. The others were more dirty and had a reddish color due to oxidation. For the four clean samples the average porosity was 18.9 per cent and the average specific yield 15.0 per cent. For the six partially altered samples the average poros- ity was 23.4 per cent and the average specific yield 18.0 per cent. This does not mean that dirty, altered gravels have a higher specific yield than clean gravels, but that representative averages can not be obtained from so few samples over so large an area. 68 DIVISION OF WATER RESOURCES PLATE XVIT 1 N 3 y 3 d o >o o "1 -"t ■* lO o ^h-c O ?. ^ ^ / /■ / 1 n3Avao kNnia3w c -IC RE OF TH ROSITY ■/ 1 13AVaO 3Nld SPECI ME NTS PO 7 / o 1 1 z D Z. jj jj r J L J u 1. / O ONVS ATlSAVaO POROSITY SEDI / / Q 1 ONVS 3savoD / L >- O / ONVS 3savoD \ O LlI Ol I I / ONVS Ani03>N • \< / ONVS 3Nld O /> 'n ONVS 3Nld AVnO AQNVS i 1 lllS^ AVID n (\J f\J 1 N 3 D y 3 d VENTURA COUNTY INVESTIGATION 69 TABLE 9 POROSITY AND SPECIFIC YIELD OF SAMPLES Porosity in per cent... Retention in per cent- Yield in per cent Samnle number 2 4 5 6 7 8 21.2 5 16.2 23.7 6.1 r.6 25.0 6.0 19.0 26.5 4.6 21.9 21.2 5.6 15.6 18.5 3 15.5 23.2 4.8 18.4 10 12 13 14 15 16 17 18 19 20.7 5 15.7 43 7 11 5 32 2 36.5 U 7 24.8 42.2 10.5 31.7 39 5 9 3 30 2 15 6 3 9 11 7 20 1 3 6 16 5 37.7 5 3 32.4 37.4 6.4 31.0 Specific Yield of Sands An inspection of Table 9 shows that gravel samples have widely varying porosities and specific yields. The same is true for sand samples. It is obvious that a representative value for specific yield of gravel or of sand can not be obtained by determining the specific yield of one or two samples from that area. The representative value should be obtained by averaging a large number of samples. In the Santa Clara River Valley there are not many localities where good gravel samples can be obtained as the surface deposits along the river are chiefly sand or silt with some streaks of gravel exposed which are not of great enough vertical thickness to sample. Gravel pits at Piru, Fillmore and Saticoj^ afford good gravel exposures. In the South Coastal Basin several hundred gravel samples were dug for porosity determination. The rock types there are similar to the rock types in the alluvium of the Santa Clara River. Plate XVII shows curves of porosity, specific retention and specific yield for 201 samples of conti- nental deposits from the South Coastal Basin. The samples were grouped, averaged and plotted according to their maximum 10 per cent grade size. By the term "maximum 10 per cent grade size"* is meant that grade size of a sample in which the cumulative total of the coarsest material reaches 10 per cent of the total sample. It is a grade size which is more sensitive to the degree of sorting than either the absolute maximum size or the mean size. For the 16 samples from the Santa Clara River Valley the average porosity, specific retention and specific yield for each maximum 10 per cent grade size was as follows: TABLE 10 POROSITY, SPECIFIC RETENTION AND SPECIFIC YIELD OF SAMPLES FROM SANTA CLARA RIVER VALLEY Maximum 10 per cent grade size, millimeters Number of samples Average porosity, per cent Average specific retention, per cent Average specific yield Hto 1 _ Ito 2 16to 32 32to 64 64 to 128 . 4 2 3 5 2 40 5 37 5 23 3 22 3 17 1 10.8 5.8 5.7 4 7 3.5 29.7 31.7 17 6 17.6 13.6 The above specific yield values for the various grade sizes for the Santa Clara River Valley samples are slightly lower than the * Bulletin No. 45, supra. 70 DIVISION OF WATER RESOURCES specific yield values for corresponding grade sizes from the South (Coastal Basin. Because of the far greater number of samples from the South Coastal Basin, it is believed that they give a more representative average than the few samples from the Santa Clara River Valley and that by comparison the values for Santa Clara can be established. For any given grade size the specific yield can be fairly accurately determined. In actual practice, the greatest difficulty lies in interpret- ing the drillers' logs, which are the basis for estimates of specific \aeld, and determining what grade sizes are meant by his terms gravel, sand, silt, muck, rock, etc. What one driller calls a coarse sand another may call a fine gravel. What one driller terms a sand in an area where good gravels are abundant he may term a gravel in areas where good gravels are scarce. It may be assumed that the term "sand" as commonly used by well drillers includes particles whose dominant grade size varies from a minimum of one-fourth millimeter to a maximum of four millimeters in diameter. As the dominant grade size for sand is commonly one grade size smaller than the maximum 10 per cent grade size, the correspond- ing maximum 10 per cent grade size limits for the drillers' term "sand" would be one-half to eight millimeters. From the specific yield curve it is seen that the average specific yield of samples having the maximum 10 per cent grade size within the limits of one-half to eight millimeters is as follows : Maxi7nu7n 10 per cent grade size Specific yield J to 1 millimeter 30.9 per cent 1 to 2 millimeters 32.4 per cent 2 to 4 millimeters 31.3 per cent 4 to 8 millimeters 29.1 per cent Average 30.9 per cent The average specific yield is 30.9 per cent. This is approximately the highest point on the specific yield curve on Plate XVII. Hence, if the driller included either coarser or finer material under his term "sand" the specific yield would be lowered. Dirty or clayey sand would also lower the specific yield. Experience in inspecting samples from drilling wells has shown that it is quite common for drillers to log fine sand as "sand." But fine sand, i.e., particles of dominant grade size of one-sixteenth to one-fourth millimeter,* has an average specific yield as shown by the specific yield curve of only 21.1 per cent. For the computations for this report a value of 27 per cent was used as the specific yield for sand. The specific yield value used for fine sand was 18 per cent. Mixtures of sand and clay occur and naturally their yield is variable. In this report a specific yield value of 9 per cent was used for sandy clay. Specific Yield of Gravels Along the river area of Santa Clara River Valley the surface deposits are of sand and silts with some gravels including cobbles up to ten inches (254mm.) in diameter. The gravel pit at Saticoy exposes very few boulders over 10 inches in diameter. The maximum 10 per * Wentworth, C. K., A scale of grade and class terms for clastic sediments, Jour. Geology, V. 30, No. 5, pp. 377-392, 1922. VENTURA COUNTY INVESTIGATION 71 cent grade size for gravels is usually one grade size smaller than the absolute niaximum size. Hence, the largest common ma:ximum 10 per cent size for the Santa Clara liiver area is 64 to 128 millimeters. The specific yield for each maximum 10 per cent grade size from 8 to 128 millimeters from Plate XVII is as follows: Maxiniu7n 10 oer cent grade size Specific yield 8 to 16 millimeters 26.6 per cent 16 to 32 millimeters 22.8 per cent 32 to 64 millimeters 18.4 per cent 64 to 128 millimeters 15.4 per cent The average for these four grade sizes is 20.6 per cent specific yield. A value of 21 per cent was used as the specific yield for gravels in the river area of Santa Clara Kiver Valley. Boulders larger than 10 inches are common in the alluvial cones of Piru, Sespe and Santa Paula Creeks, and in the Timber Canyon Cone. The specific yield for each maximum 10 per cent grade size from 8 to 512 millimeters from Plate XVII is as follows : Maximum 10 per cent grade size Specific yield 8 to 16 millimeters 26.6 per cent 16 to 32 millimeters 22.8 per cent 32 to 64 millimeters 18.4 per cent 64 to 128 millimeters 15.4 per cent 128 to 256 millimeters 13.7 per cent 256 to 512 millimeters 13.7 per cent The average specific yield for these six maximum 10 per cent grade sizes is 16.8 per cent. But boulders are common in these cones up to 40 i«iches (1016mm.) in diameter and larger. No mechanical analyses were made on samples whose maximum 10 per cent grade size was greater than 512 millimeters (20 inches). However, there is no good reason to believe that the specific yield curve (Plate XVII) should rise as the maximum 10 per cent grade size becomes greater than 512 millimeters. Using 13.7 per cent as the specific jdeld for the 512 to 1024 millimeters and 1024 to 2048 millimeters maximum 10 per cent grade sizes, and averaging these with the other six grade sizes from 8 to 512 millimeters, gives an average specific yield of 16.3 per cent. As the larger maximum 10 per cent grade sizes are more common than the 8 to 16 grade size, a value of 15 per cent was used as the specific yield for gravel on the north side area of Santa Clara River Basin. Gravels vaiy from good, clean gravel to cemented gravels or mixtures of gravel and clay. Their yields vary dei)ending on the degree of cementing or the proportion of clay. Specific yields were assigned in the ratio of 3-2-1. That is, where the specific jield was 21 per cent for gravel, tight gravel was assigned a specific yield of 14 per cent and gravelly clay 7 per cent. For the north side areas of the Santa Clara River Valley where the specific yield of gravel was 15 per cent, tight gravel was assigned a specific yield of 10 per cent and gravelly clay 5 per cent. Specific Yield of Clay True claj^ can be considered as nonproductive, or, at best, as yielding slowly 1 or 2 per cent. Well drillers have a tendency to log sandy clays and sometimes silts as clays but sandy clays and silts should 72 DIVISION OF WATER RESOURCES PLATE XVIII >- Ml UJ m o U. -) L- O o a: n o CM p Q 7^ Q- H < (/) O h 1 a: If) rr -J P - o < Z) 2 a UJ U- UJ 1- asins were combined into natural groups. The formations were averaged by 50 foot intervals from the ground surface to depth 250 feet and the per cent specific yield determined for each interval. The formations were listed under eight headings: (1) True Clay; (2) Doubtful Clay; (8) Sandy Clay; (4) Gravelly Clay; (5) Sand; (6) Fine Sand; (7) Tight Gravel; (8) Gravel. The centers of gravity of the well groups were marked on a map, and given the specific yield values determined by the w^ell group averages. Then specific yield contours were drawn, so that all points on any contour have the same specific yield. This was done for each 50-foot depth interval. Plate XVIII shows specific yield contours for Piru. Fillmore and Santa Paula Basins for the depth interval 150 to 200 feet. Oxnard Plain, Nonpressure Area On the Oxnard Plain representative gravel samples were not avail- able. The same procedure was followed as in Santa Clara River Valley and the same specific yield values were used. Boulders larger than those appearing in the Saticoy gravel pit should not occur in any abundance in the river cone deposits of sand and silt to the southwest. Averages on samples of marine sands in South Coastal Basin show that their specific yield is no higher than continental sands. From the well group averages, specific yield contours were drawn for each 50-foot depth interval. One set of these contours is presented on Plate XIX to illustrate the general shape of the specific yield con- tours in the Oxnard Plain nonpressure area, where the condition of deposition of sediments changes from that of a confined valley to an alluvial plain. OJai Basin In the Ojai Basin there are very few localities where good samples can be taken for determining the porosity and specific yield of the 74 DIVISION OF WATER RESOURCES PLATE XIX VENTURA COUNTY INVESTIGATION 75 gravels because the gradation is very rapid between the very large boulders at the northeastern end of the valley and the silts and clays at the southwestern end of the valley. Most of the gravels exposed contain boulders so large that rei)resentative samples can not be taken. Only two gravel samples were dug iu Ojai Valley. They were taken from the bank of San Antonio Creek north of the Ojai Avenue Bridge. Their mechanical analyses are shown in Table II. No specific gravity determinations were made on the particles under 8 millimeters in diameter. A specific gravity of 2.68 Avas assumed as this is the approxi- mate specific gravity of particles derived from areas of crystalline rocks. As the alluvium of Ojai Valley is derived from sedimentary formations, the specific gravity assumed may be slightly high and the resulting porosity and specific yield slightly high. TABLE 11 POROSITY AND SPECIFIC YIELD OF GRAVEL SAMPLES FROM OJAI VALLEY Sample No. 20 Porosity in per cent 21.9 24.1 Retention in per cent 2.1 2.1 Yield in per cent 19.8 22.0 Although computations of capacity were made for this basin they Avere not used as it appears difficult to correctly evaluate the voids. Upper Ventura River Valley 111 Upper Ventura River Valley the extremely large size of the boulders make it impractical to dig field samples to determine porosity. Boulders occur as large as 7 feet in diameter. So far as is known, no determination of porosity, specific retention or specific yield have been made anywhere on samples containing boulders over 512 millimeters (20 inches) in diameter. For the Upper Ventura River Valley it is estimated that the average specific yield of the alluvium composing the basin is not over 10 per cent but storage capacity computations were not used. BASIN CAPACITIES AND STORAGE CHANGES Change in Storage Computations To compute the change in storage between water tables, isopiestics were drawn for all recorded and hypothetical water tables. As defined by Meinzer,* an isopiestic line of an aquifer (water- yielding formation) is an imaginary line, all points on Avhich have the same static level. It is a contour of the piezometric surface of the aquifer. A piezometric surface may be an artesian pressure surface, which is above the upper surface of the zone of saturation ; a normal- pressure surface, which coincides with the upper surface of the zone of saturation ; or a subnormal pressure surface, which is below the upper surface of the zone of saturation. A normal pressure surface is generally the same as the water table. For this report, the storage * Meinzer, O. E. Outline of Ground Water Hydrology, U. S. Geological Survey, Water Supply Paper 494, pp. 38-39, 1923. 76 DR'ISION OF WATER RESOURCES PT^ATE XX VENTURA COUNTY INVESTIGATION 77 computations were made only for those basins iiaving a normal-pressure surface. Henee, the isopiestics used are contours on top of the zone of saturation. Computations of change in storage were made for the following basins : Piru, Fillmore, Santa Paula, Oxnard Plain nonpressure area, Ojai Valley and Ventura River. In the other basins the geologic con- ditions are such and data so meagre that no attempt at computations was made. The elevations of the water tables at the end of the pumping season were used in computing change in storage. These elevations are termed fall measurements, although they may vary from September to January. Piru Basin Computations were made of the change in storage resulting from the lowering of the water table from fall 1927 to fall 1932. The change in storage was as follows : Period Acre-feet Fall 1927 to fall 1928 — 4,100 Fall 1928 to fall 1929 — 9,900 Fall 1929 to fall 1930 — 3,800 Fall 1930 to fall 1931 — 4,300 Fall 1931 to fan 1932 +13,400 Net change — 8,600 A computation was made of the storage capacity between the water table of fall 1931, which is the lowest water level on record, and a hypothetical water table twice as far below the w^ater table of fall 1927 as was the water table of fall 1931. (See Plate XX.) The storage capacity as computed is 21,300 acre-feet, making a total storage capacity below the water table of fall 1927 of 43,400 acre-feet. There is, of course, additional capacity below but this elevation is arbitrarily assumed as bottom of the reservoir. Hypothetical water tables were drawn for each 20-foot rise above that of spring 1928 at the spreading areas. Storage between the water table of spring 1928 and fall 1927 is computed to be 2200 acre- feet. The storage capacity computed for each successive 20-foot rise is as follows : First 20-foot rise 9,700 acre-feet Second 20-foot rise 12,700 acre-feet Third 20-foot rise 10,600 acre-feet In spring 1928 there was an area of rising water extending along the bed of the Santa Clara River from the western boundary of Piru Basin eastward about 2000 feet. It is estimated that for the above hypothetical water levels above the water level of spring 1928 the rising water area would be extended eastward as follows : Distance from western end Water level of Piru Basin Spring 1928 2,000 feet Spring 1928 -f20 feet 5,000 feet Spring 1928 -|-40 feet 7,000 feet Spring 1928 -f60 feet 15,000 feet It is believed that if the water table rose higher than 60 feet above the level of spring 1928 the flow of rising water would be so 78 DIVISION OF WATER RESOURCES PLATE XXI 19Aa| E3S 8Aoqe |9aj. ui uo!|ba3|3 "^ ^ ks >jisva Tyid - ^ A ^ QC / \ X \ ^/ \ \ BASIN o > a: '\' 'A LJ \ \ CO UJ CO ' /\\^ I o ? \\ \ Q z « ■ - \ v\ o ID Z a ' **" \ \ \ _l O (/I 5 ' 0) \ > \ w u. < \ \ e; CD V \ \\ CO ™ \ w LJ UJ ^ \\\ o cr \\\ z O 2 wv ^ \ L. _j \\ o _j u. M liJ ^\ _J \ CD < \ ^ 1- \ QC \ UJ \ h- \ S \ \ t . \ 1 1 1 NISVJ 3 vinvc VXNV s \ |8Aa| B8S 8Aoqe \3dj u\ uO!;eA3|3 VENTURA COUNTY INVESTIOATIOX 79 fi'reat that the storaji'e woiiUl not be retained : lienee the storajre eapaeity has not been computed for hypothetical water tables above that of spring 1928 at the spreading areas. A summary of the storage capacities for various intervals in I'iru Basin is as follows : Interval Acre-feet Above level of fall 1928 35,200 Between level of fall 1928 and fall 1931 (lowest recorded) 22,100 Between level chosen as bottom and level of fall 1931 21,300 79,000 Plate XX is a longitudinal profile constructed from isopiestie nuij^s and showing various water tables. Fillmore Basin Computed change in storage during the period of investigation is as follows : Fall 1927 to fall 1931 — 15,800 acre-feet Fall 1931 to fall 1932 + 10,400 acre-feet Xet change — 5,400 acre-feet The computed change between the water tables of fall 1927 and spring 1928 was a gain in storage of 5000 acre-feet. The water table of spring 1928 stood within 20 feet of the ground surface along the course of the Santa Clara Kiver through the basin. A small vertical rise of water level above the water table of spring 1928 would cause a large increase in area and volume of rising water. An estimate of the amount of available storage capacity in Fill- more Basin above the water level of spring 1928 was made by drawing isopiestics coinciding with the ground surface contours along the bed of the Santa Clara River and coinciding, along the borders of the basin, with the isopiestics of equal elevation for spring 1928. The computed storage capacity between this hypothetical water table repre- senting a full liasin and the water table of spring 1928 was 12,000 acre- feet giving a total capacity above the fall 1927 level of 17,000 acre-feet. Adding this to the capacity between the fall 1927 and fall 1931 levels gives 33,000 acre-feet. There is of course much capacity below the 1927 level available with small pumping lift. (See Plate XXI.) Santa Paula Basin Computed changes in storage during the period of investigation are as follows : Period Acre-feet Fall 1927 to fall 1931 — 14,400 Fall 1931 to fall 1932 + 8,300 Net change — 6,100 The computed gain in storage of Santa Paula Basin from fall 1927 to spring 1928 was 1900 acre-feet. In spring 1928 there was rising water in Santa Clara River throughout its course through the basin. Any addition of water to the basin above the water table of spring 1928 would increase this flow and hence, there is no practical storage capacity above that water table. 80 DIVISION OP WATER RESOURCES PLATE XXII 19A3| eas aAoqe ;a9j ui uoi;eA9|3 o o o o o o o NISV9 TT CM o as tX> ° vnnvd viNvs > ^ ^ > >- s ^ \ > \\ 1 1 . ^ \ \ I \ 1 \ \ V \ \\ O ^'^ \ ^ \ \ 1 1° > DC \ ■< i { 1 \ ^ LJ 123 vs \\ \ I y a: £E < \ t ll \ c 1 D UJ \ ^l \ 1 --3 LO A \ r 1 ^ ' a: \ \ \ w 1 < ' Id . 1 - in DERGRO NON-PRES \ ' 111 1 E c \ 3 level N NO o c ro Q OF UN PLAIN \ 1 f i 1 1 2 • . . Q \ 1 < U q: ?1 ' 1 z 1 X . CO z o s\ [™ 1 1 < X 1 1 1- o a: 1 1 UJ \ fi \\ 1 1 1- \ i 1 . A o 'o ..lL. i/9anss3ad o NIVId QdVNXO VENTURA COUNTY INVESTIGATION 81 The water levels of si)riiig each year eoineide with the yrrouiid surface at the Santa Clara Kiver channel. Durinji' the pumping season there is a slight lowering of the water level below the ground surface in the Santa Clara River channel in the central part of the basin. Oxnard Plain Nonpressure Area Computations Avere made for the Oxnard Plain nonpressure area for the fall Avater tables of 1927 to 1932 inclusive, and the yearly change in storage computed. Several of the water levels are shown on Plate XXII. The estimated yearlv changes in storage from fall 1927 to fall 1932 are as follows : Period Acre-feet Fall 1927 to fall 192S — 20,300 Fall 1928 to fall 1929 — 26,000 Fan 1929 to fall 1930 ^13,800 Fall 1930 to fall 1931 — 10,700 Fall 1931 to fall 1932 +13,100 Net change — 57,700 The computed gain in storage from fall 1927 to spring 1928 w^as 5000 acre-feet. As shown on Plate XXII the water table of spring 1928 was within five feet of the ground surface under the Santa Clara River channel at the dividing line between the pressure and nonpres- sure area. A slight rise in water level above the level of spring 1928 would cause the ground water to flow as perched water over the artesian area. Hence, there is little available storage capacity above that water table and no attempt has been made here to estimate it. Ojai Valley Estimates of change in storage did not appear to cheek sufficiently with estimates made by other methods and were not used. No storage space can be counted on above the water table of spring 1928. In fact, the water table of spring 1928 was itself only a tempo- rary high water level. After the heavy rains of winter 1926-27 the water table rose to the ground surface near the city of Ojai, flooding the ditches during the construction of the Ojai sewer system, and rising water drained into the San Antonio Creek at the lower end of the basin. Upper Ventura River Valley Because of the smaller number of wells in Upper Ventura River Valley and because of their distribution it was impossible to make reliable computation of change in storage or of total storage. 6 — 8367 — 8375 CHAPTER VI RAINFALL PENETRATION^ Rainfall is disposed of iu four parts, (1) surface run-off, (2) evaporation, (3) transpiration, and (4) percolation. Only the last part passes to the ground water supply. Under ordinary topographic and soil conditions surface run-off will occur when the precipitation is of sufficient intensity'. A part of the surface run-off from valley floors may be termed local as it flows directly into depressions and then percolates into the ground without reaching the main surface streams. That portion of the precipitation retained temporarily in the top layer of the soil or intercepted by plants is returned to the atmosphere by evaporation. Of the water which percolates into the ground a portion is stored in the soil within the root zone and subsequently is transpired by plants, while the remainder penetrates below the root zone and joins the ground water. The amount penetrating to ground water may be determined indirectly if values are established for the other factors entering into the disposition of rainfall, since all water penetrating below the root zone and beyond capillary reach of plant rootlets and evaporation must ultimately reach ground water, excepting only moisture lost in the form of vapor due to the circulation of air in the soil below the root zone. This loss is very small and is disregarded in the following discussion. DESCRIPTION OF SOILS IN VENTURA AREA** The soils of the Ventura area may be broadly classified in four groups namely, (a) residual soils, or those derived from the disin- tegration and weathering of consolidated rocks in place; (b) old valley- filling and coastal plains soils, consisting of elevated and weathered unconsolidated water-laid deposits; (c) recent alluvial soils derived from sediments that have not undergone material changes or internal modification since their deposition, and which are still in process of formation; and (d) wind-laid soils, confined to a very narrow belt of drifting sand dunes along the ocean front. Besides these soils, parts of the area are occupied by lands mainly nonagricultural, which are separated from the preceding groups on practical economic grounds rather than on characteristics of origin and mode of formation. The first three groups comprise the soils of nearly all of the agricul- tural lands of the State, the residual soils predominating in the moun- tainous regions, the old valley-filling and coastal plains soils usually being most extensive at lower elevations and along the sea coast, and the recent alluvial soils prevailing on the flooi's of most of the valleys. * By Harry F. Blaney, Irrigation Engineer, Division of Irrigation, Bureau of Agricultural Engineering, U. S. Department of Agriculture. I'repared under the direction of W. W. McLaughlin, Chief of the Division of Irrigation. ** Abstracted in part from Soil Survey of Ventura Area, Bureau of Soils, U. S. Department of Agriculture. (1917.) (82) VENTURA COUNTY INVESTIGATION 83 Tlic ]-esi(liial soils, wliicii nw rntlier inextensive in this survey, occur pi'iiK'ipally in tlic cjistcrn find southeastern parts of the area. The old val]ey-fillinf>- soils ai-c much more extensive than the residual soils, and the recent alluvial deposits far exceed the coml)ined area of the other two. Each of tlie groups mentioned includes a number of soil series, and each series is represented by one or more soil types. The residual soils of the area are identified with hilly and mountain- ous regions and are formed from the weathering of rocks in place. They are associated with rough broken and stony land in many j)laces and have some rock outcrop locally. This group includes the Alta- mont, Diablo, and Olympic series. The soils of the old valley-filling and coastal plains group are derived from elevated, unconsolidated, water-laid deposits which have undergone marked changes since they were laid down. The five series belonging in this group are the Rincon, Pleasanton, Ojai, Madera, and Montezuma. The recent alluvial soils form by far the most extensive group of tlie area. They cover nearly all of the Santa Clara River fan on the plains in the region about Oxnard, and occur also as river bottom deposits and as numerous alluvial fans lying in the main stream valleys at the mouths of tributary creeks and drainage ways. These soils are classified in three series. Those whose materials come originally from sedimentary rocks and old valley-filling deposits are in the Yolo and the Dublin series and those from deposits washed from areas of basic igneous rocks are in the Vina series. Table 12 shows percentages of ditferent soils in the Ventura area. TABLE 12 PERCENTAGES OF DIFFERENT SOILS IN VENTURA AREA Type Per cent Type Per cent 56.7 7.1 6.0 3.5 3.3 2.4 2.2 1.7 1.7 1.6 13 11 1.1 1.0 0.9 0.9 8 .8 Yolosilty clay loam Rincon fine sandy loam 8 Rinconloam . ._ .7 Yolo silt loam Vina fine sandy loam .6 .6 Yolo loam 6 Yolo sand--- Dublin loam .5 .5 .4 Yolo verv fine sandv loam Tidal marsh .3 Rincon clay loam . Pleasanton gravelly loam .3 .2 Olympic clay adobe . .2 Ojai verv fine sandy loam Altamont clay adobe--- - . .1 .1 SOIL MOISTURE STUDIES IN 1931-32 The penetration of any one season's rainfall depends on the initial moisture conditions in the soil at the beginning of the rainy season and the amount of evaporation and transpiration occurring during that season. These factors vary with the cover, but the area under con- sideration can be classified according to crops grown. For example, citrus trees are shallow rooted and cause a small initial deficiency of soil moisture in the fall, while deciduous trees and native brush are deep rooted and use the soil moisture to greater depths, thus causing 84 DIVISION OF WATER RESOURCES a large initial fall moisture deficiency. Soil moisture studies are relied upon to determine values for the initial fall moisture condition and subsequent evaporation and transpiration losses. With these factors known, the rainfall penetrating below the root zone can be calculated. Sixteen rainfall penetration plots were established on typical areas on the valley floors of various subbasins, as indicated in Table 13 and Plate I. Soil moisture conditions at these stations were studied during the period October, 1931, to May, 1932, for the purpose of determining the initial soil moisture deficiency, evaporation-transpiration, field capacity, storage of rain water in the soil and the downward percola- tion of the water. Soil samples were taken with standard soil-sampling tubes in one-foot sections to depths of from 10 to 17 feet reaching soil conditions well below the major root zone of most native and crop plants. Standard laboratory practices were used in determining the moisture content of the soil samples. Table 14 summarizes the results of soil moisture studies on the rainfall penetration plots. TABLE 13 DESCRIPTION OF PLOTS SELECTED FOR RAINFALL PENETRATION EXPERIMENTS IN VENTURA COUNTY, 1931-32 Plot No. Location Crop Age, years Soil type Annual rainfall 1931-32, inches A g.9 mi. NW. of Saticoy Heavy weeds and grass (non- irrigated) Yolo silt loam 17 56 B 0.5 mi. N. and 0.5 mi. E. of Simi -. Apricots (irrigated) Yolo fine sandy loam 15 91 C 0.5 mi. S. and 0.3 mi. W. of Moorpark Walnuts (irrigated) 16 Yolo fine sandy loam _ . 15 72 D 1.8 mi. SE. of Saticoy 16 55 E 2.2 mi. E. of Ojai Navel oranges (irrigated). __ 12 Yolo gravelly fine sandy loam. 26.11 F 3.0 mi. W. of Ojai Apricots (nonirrigated) 6 Ojai very fine sandy loam 24.43 G 0.5 mi. NE. of El Rio Scattered weeds and grass Yolo fine sandy loam 16 55 H 1.3 mi. S. and 5.0 mi. E. of Saticoy, Las Posas District. - Walnuts (irrigated) 15 15.77 I 1.3 mi. NW. of Bardsdale Walnuts (irrigated) 25 Yolo very fine sandy loam 21.91 J 1.3 mi. NW. of Bardsdale Navel oranges (irrigated)... 10 Yolo very fine sandy loam 21 91 K 1.3 mi. SE. of Piru... Walnuts (irrigated) 16 Yolo fine sandy loam 20.91 T, 2.0 mi. SW. of Piru- Navel oranges (irrigated)--. 10 Yolo gravelly fine sandy loam. 21.08 M 0.5 mi. SW. of El Rio .__ Beans (irrigated) Yolo fine sandy loam 16.46 N 2.7 mi. NW. of Bardsdale Walnuts (irrigated) 21 Yolo fine sandy loam 21.75 2.5 mi. SW. of Fillmore Lemons (irrigated) 17 Yolo gravelly fine sandy loam. 21.75 P 2.5 mi. SW. of Fillmore Walnuts (irrigated) 23 Yolo fine sandy loam 21.75 The results of the soil sampling indicate that penetration occurred below the root zone of all the shallow rooted crops, such as citrus and beans, which had been irrigated regularly during the summer months. In areas of sufficient rainfall penetration occurred in irrigated decidu- ous lands. VENTURA COUNTY INVESTIGATION TABLE 14 85 SUMMARY OF RESULTS OF SOIL PENETRATION PLOTS IN MOISTURE STUDIES ON RAINFALL VENTURA COUNTY. 1931-32 Plot No. Crop Depth in feet Field capacity, per cent Initial soil moisture deficiency in inches Depth of penetration in feet A Grass and weeds (nonirrigated) ... 0- 6 6-10 0-10 20.6 13.3 15.1 3.5 18.6 93^ B 0- 9 9-11 0-11 12 3 7.2 6.7 6.7 No dry soil c Walnuts 0- 2 2- 4 4- 8 8- 15 0-15 9.7 28.6 6.4 10.0 3.0 4.4 2.6 0.7 10.7 No dry soil D 0- 5 20.1 5.0 Below root zone E 0- 3 3- 6 0- 6 18.1 10.2 2.1 0.8 2.9 Below root zone F 0- 6 17.0 15.6 G Grass and weeds (nonirrigated) 0- 6 6-10 0-10 14.5 5 10.6 3 3 13.9 9 H Walnuts- . 0-15 25.0 9.6 No dry soil I 0-15 16.0 11.6 No dry soil J Oranges 0- 6 18 2 3.7 Below root zone K 0- 7 7-15 0-15 21 1 4.2 6.9 1.1 8.0 No dry soil L 0- 6 12.9 2.5 Below root zone M Bare bean land - - 0- 5 15.5 4.1 Below root zone N 0- 6 6-12 . 0-12 26 1 16.6 12.9 —1.8 11.1 No dry soil 0- 6 15.0 —0.1 Below root zone P Walnuts. 0- 6 6-12 0-12 12.1 10.0 7.2 7.8 15.0 No dry soil Penetration did not occur in the grass and weed areas where the rainfall was less than 20 inches. In grass and weed plots, A and G, the soil was dry to a depth of 17 feet. The results indicate that no rainfall had penetrated below the roots in these plots for at least five years, since the annual rainfall during this period was less than that of 1931-32. The deficiency of soil moisture at the beginning of the rainy season is high, and should not be considered representative of sections receiving greater rainfall. FACTORS IN RAINFALL DISPOSAL Initial Soil Moisture Deficiency As previously suggested, there is at the beginning of almost every rainy season an initial deficiency of soil moisture within the root zone in the district studied. During the summer months the capillary 86 DIVrSION OF WATER RESOURCES moisture is more or less completely withdrawn from the soil within the root zone by the processes of evaporation and transpiration. In nonirrigated soil the moisture content may be depleted to the wilting point throughout the greater portion of the root zone, while in irrigated soil, because of the artificial application of water, the moisture content may be much greater. Thus the deficiency of soil moisture below field capacity at the beginning of the rainy season is an important factor in limiting the amount of rainfall penetrating to ground water. Aside from the penetration due to local surface run-off, there can be no material penetration below the root zone until all of the soil within that zone has been supplied with its field capacity. The moisture con- tent of the soil at the beginning of the rainy season varies with the last crop raised, type of soil, amount of irrigation water applied, evapora- tion, transpiration by plant life, depth of water table and other con- ditions. Citrus trees are shallow-rooted and their effect upon initial deficiency of soil moisture is small, while grape vines, deciduous trees, and native brush are deep rooted and draw from the soil moisture to greater depths, thus causing gi-eater moisture deficiencies. The initial fall deficiency in moisture content of the soil is deter- mined as follows: Soil samples are taken previous to the beginning of the rainy season and again later when the soil is at its field capacity, either as the result of rainfall or irrigation. The moisture content of these soil samples is determined by standard methods. The difference between the moisture content of the soil at field capacity and initial moisture content in the fall of the year is equal to the initial fall deficiency of soil moisture. This method was used to determine the initial soil moisture deficiency at the sixteen rainfall penetration plots previously described. Similar soil moisture data were obtained from the Santa Paula Citrus Fruit Association, Sespe Ranch, and Limoneira Ranch, and the initial soil moisture deficiencv was calculated. The results are summarized in Table 15. After considering many other observations made in southern Cali- fornia during the past five years, the values shown in Table 16 are taken as representative of Ventura area conditions, and are used in computing rainfall penetration. Run-off Hydrographers making the Ventura investigations have determined the rate of run-off on certain known areas. A part of the surface run-off from the valley floors may be termed local as it flows directly into the depressions and percolates into the ground without reaching the main surface streams. Of the five rainfall seasons studied, that of 1931-32 was the only one having sufficient rainfall to cause measurable run-off from the valley floors into the main river channels, and such run-off is thought to be limited to the two basins having the highest rainfall, Ojai Valley and Ventura River. The run-off from the rain- fall during the 1931-32 season is estimated to be 1.4 inches for the penetration area in Ojai Valley and 1.6 inches in Ventura River Basin, VENTURA COUNTY INVESTIGATION 87 TABLE 15 SUMMARY OF INITIAL SOIL MOISTURE DEFICIENCY DATA IN VENTURA COUNTY, 1931 Location 1 mi. NE. of Somis }^ mi. NE. of Somis 2 mi. W. of Piru... _ 1 mi. W. of Santa Paula 1 mi. K. of Santa Paula 3 mi. W. of Santa Paula 2 mi. W. of Santa Paula 8 mi. E. of Santa Paula 3 mi. W. of Sania Paula 4 mi. E. of Santa Paula 6}^ mi. W. of Santa Paula 6 mi. W. of Santa Paula 2J^ mi. W. of Santa Paula 2 mi. W. of Santa Paula 1 mi. E. of Ventura J4 mi. E. of Saticoy 2Hnii- E. of Santa Paula 5 mi. E. of Ventura 5 mi. E. of Ventura -. 2 mi. W. of Fillmore 2 mi. W. of Santa Paula 2.2 mi. E. of Ojai 1.3 mi. NW. of Bardsdale 2 mi. SW. of Piru Sespe Ranch, Fillmore _ Sespe Ranch, Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore _ Sespe Ranch, Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore 2 mi. W. of Piru Piru District 2 mi. W. of Santa Paula 2 mi. W. of Santa Paula 7 mi. W. of Santa Paula 2.5 mi. SW. of Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore Sespe Ranch, Fillmore 1.3 mi. S., 5 mi. E. of Saticoy 1.3 mi. N W. of Bardsdale 1.3 mi. SE. of Piru 2.7 mi. NW. of Bardsdale 2 5 mi. SW. of Fillmore^ ^ mi. N., J^ mi. E. of Simi }^ mi. S., 0.3 mi. W. of Moorpark Soil type Citrus Irrigated Usual Practice Rincon fine sandy loam Rincon fine sandy loam Heavy type Yolo loam... Yolo silt loam and Yolo loam, gravelly series Yolo series, badly mixed, some gravel Hea\T textured Yolo silt loam Yolo eravelly loam Several soil types, Yolo gravelly loam, some Rincon loam Yolo silt loam, some gravel Yolo silt loam or Yolo fine sandy loam. . . Yolo silt loam, some gravel Yolo silt loam Y'olo loam some gravel, some Rincon loam Yolo fine sandy loam, Yolo loam Yolo loam, hea\-y texture Yolo fine sandy loam Y'olo gravelly fine sandy loam Yolo silt loam Y'olo fine sandy loam, some rock and gravel, very fine soil Yolo fine sandy loam, gravelly type Yolo silt loam, fine type Yolo gravelly fine sandy loam Y'olo very fine sandy loam Yolo gravelly fine sandy loam Rincon loam over red clay Y'olo fine sandy loam Yolo fine sandy loam Yolo loam. Yolo silt loam. Y'olo fine sandy loam Yolo fine sandy gravelly loam Yolo gravelly loam Citrus Irrigated Just Prior to Nov. 1, 1931 Yolo fine sandy loam Y'olo fine sandy loam Y'olo fine sandy loam Y'olo silt loam, gravelly type Rincon fine sandy loam Y'olo gravelly fine sandy loam Yolo fine sandy loam Y'olo fine sandy loam Yolo fine sandy loam Yolo gravelly loam Deciduous Irrigated Yolo very fine sandy loam Y'olo very fine sandy loam Y'olo fine sandy loam Yolo fine sandy loam ; Y'olo fine sandy loam Yolo fine sandy loam Yolo fine sandy loam Crop Oranges. Oranges. Oranges. Lemons - Lemons. Lemons. Lemons. Lemons. Lemons. Lemons. Oranges. Lemons - Lemons. Lemons. Lemons. Oranges. Lemons. Oranges. Lemons. Lemons. Lemons. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges. Oranges- Oranges. Oranges. Lemons. Lemons. Oranges. Lemons. Oranges- Oranges. Oranges. Oranges. Walnuts Walnuts Walnuts Walnuts Walnuts Apricots Walnuts Initial deficiency in inches 2. 3 3.3 3.7 3.1 2.8 1.0 3 2 2.3 3.5 1.5 2.8 2.1 2.8 1.8 2.7 1.8 1.7 2.0 3.5 2.0 2.1 3.0 3.7 2.5 3.3 2,9 1.3 3.5 1.0 3.4 2.3 1.3 —1.0 —0.2 1.0 0.0 0.8 —0.1 0.5 0.8 0.7 2 9.6 11.6 8.0 11.1 15.0 6 3 10.8 88 DIVISION OF WATER RESOURCES TABLE 16 INITIAL SOIL MOISTURE DEFICIENCIES USED IN RAINFALL PENETRATION CALCULATIONS IN VENTURA COUNTY Type of land Initial soil moisture deficiency, in inches Citrus (irrigated just prior to rainy season) Deciduous trees and vineyard Truck and miscellaneous (irrigated) Peans (irrigated) 10 3 4 6 3 7 10 Bare land and rjver-wash 3 Evaporation and Transpiration Evaporation loss after a rainstorm is influenced by many factors such as temperature, wind movement, soil type, kind of vegetation, interception, periods between storms, etc. Observations made in southern California during the past five years indicate that the average evaporation loss from the top soil is about one-half acre-inch per acre after each rainstorm.* After careful consideration of all data collected from cooperative irrigation investigations made since 1926 in southern California, the average transpiration for the winter period for all active growing agricultural crops is taken as 1 acre-inch per acre per month.** Inves- tigations have shown that bare land and vineyards and deciduous orchards that are clean cultivated have no material transpiration loss during the winter period. Studies in the Santa Ana River Valley show^ the average winter evaporation-transpiration rate per 30 days for grass and weeds to be 2 inches, and for brush 2.4 inches. Observations made on grass and weeds near Santa Paula during the winter of 1931-32 confirmed these values. CALCULATIONS For the purpose of completing the hydraulic accounting in this report, an estimate has been made of the contribution of rain falling on the valley floor to the ground water supply for the rainy seasons 1927-28 to 1931-32, inclusive. The locations" of the thirteen basins considered are shown on Plate I. The same total seasonal rainfall may give entirely dilferent pene- tration due to varying intensity and distribution of storms. Winter irrigation also varies with the season and influences the amount of penetration. Rainfall records from thirty stations were used, usually several records being available in each basin. Computations were made for each rainfall station and the average of the stations taken as the penetration for the basin. • Bulletin No. 33, Division of Water Resources, "Rainfall Penetration and Con- sumptive Use of Water in Santa Ana River Valley and Coastal Plain." Bulletin No. 19, Division of "^^ater Resources, "Santa Ana Investigation." ** Bulletins Nos. 1 !i and .33, supra. VENTURA COUNTY INVESTIGATION 89 The calculations may be divided into two divisions: those for determination of penetration of rainfall in inches for various crop, cover and land classifications, and those for the determination of the total amount of penetration in acre-feet. , Under the first of these, values for initial soil moisture deficiency, ruu-otf, evaporation and transpiration losses, previously given, have been used. These were analyzed by months and deducted from the rainfall. The remainder is considered to penetrate below the root zone and eventually reach the ground water. Assumptions are for average soil conditions. An example of detailed calculations of rainfall pene- tration for one station is given in Table 17. TABLE 17 AN EXAMPLE OF DETAILED CALCULATIONS OF RAINFALL PENETRATION IN INCHES AT STATION 83, 1931-32* Factors Oct. Nov. Dec. Jan. Feb. Mar. Total Crop Rainfall 2.6 1.0 1.0 .6 19 7.8 10 1.9 4.9 3 1.7 1.0 1 4 — .7 .7 5.2 10 1.5 2.7 2.0 10 —1.0 1.0 5 irrigated usual prac- Soil moifture deficiency. _ 2 5 Rainfall 2 6 1.0 1.0 .6 .1 7.8 1,0 1.9 4.9 4.9 17 1.0 1.4 .7 5.2 1.0 15 2 7 2.0 1.0 —1.0 1,0 7.0 Run-off Soil moisture deficiency. _ 0.5 Rainfall 2.6 1.0 16 8.4 7.8 19 5 9 2 5 17 11 ,3 2.2 5 2 1.5 3.7 15 •0 1.5 Transpiration Soil moisture deficiency.. 10.0 Rainfall 2.6 1.0 1.6 8.4 7.8 19 5 9 2.5 1.7 1.0 1.4 — .7 3 2 5.2 1.0 1.5 2 7 .5 10 — 10 1.5 Deciduous, cover Run-off - . cropped Soil moisture deficiency.. 10 *Total seasonal rainfall, 17.54 inches. No winter irrigation. Run-off from the valley floors into the main surface streams was considered negligible except for the Ojai Valley and Ventura River Basin during the 1931-32 season, as previously stated. The deficiency of soil moisture at the beginning of the rainy season varies considerably depending primarily upon the last crop grown. The values used in the computations are shown in Table 16. Evaporation loss for each month was computed from daily rainfall records on the basis of one-half inch loss after each storm. The transpiration loss for all active growing agricultural crops was taken as 1 inch per month for the winter period. This loss was deducted for cover crops beginning with January. Transpiration loss for bare land and vineyards and deciduous orchards that are clean cultivated w-as considered negligible during the winter period. For native vegetation, evaporation and transpiration losses were combined 90 DIVISION OF WATER RESOURCES at the rate of 2 inches per month for grass and weeds and 2.4 inches for brush provided sufficient rain fell to meet their demands. In the case of grass and weeds, no transpiration is charged until two weeks after the first effective rain. The effect of irrigation during the rainy season upon rainfall pene- tration was estimated from records available. Such irrigation will increase the moisture content of the soil and may increase rainfall penetration. At the same time, considerable irrigation water may penetrate with the rainfall and should be classed as return water. A summary of calculations of rainfall penetration in inches in each basin for the various classifications and the five seasons studied is given in Table 57, opposite page 200. This completes the first part of the computations. As previously stated, the second part of the computations consists of determining the total rainfall penetration in acre-feet for each basin. The penetration in inches for each crop, cover and land classification is multiplied by the area. The results reduced to acre-feet are sum- marized in Table 18 for each basin and season. TABLE 18 ESTIMATED RAINFALL PENETRATION BELOW ROOT ZONE IN ACRE-FEET* Basin 1927-28 1928-29 1929-30 1930-31 1931-32 Piru Fillmore 860 890 320 150 290 1,170 2,650 680 340 720 1,7.50 2,550 950 470 900 1,700 2,950 900 520 850 5.050 s,270 4,770 1,740 Montalvo, South 3,3!0 Subtotal _ 2,510 130 80 320 180 370 5,560 400 520 710 240 460 6,620 620 520 790 190 320 6,920 470 530 780 370 580 23,140 1,940 3,430 Las Posas (Moorpark) - ._ 4,980 460 Simi 1,600 Subtotal Ojai Valley Ventura River 1,080 120 620 220 2,330 50 710 240 2,440 310 570 250 2,730 200 710 310 12,410 2,120 3,900 1,600 Subtotal 960 1,000 1,130 1,220 /•,620 4,550 8,890 10,190 10,870 43.170 'Computed by the Division of Water Resources from data in this chapter and other information. CHAPTER VII QUALITY OF WATER=i This report is based on tlie analyses of 1580 samples of water from 440 locations within the area. The analyses were made in three differ- ent laboratories, and consequently the methods of analysis used and the constituents reported were not always the same. In tabulating the analytical results the aim has been to obtain such uniformity as could be achieved by recomputation without sacrificing essential accuracy. Of the analyses reported 1117 are classed as complete and 463 as partial. The distinction between these two classes is, of necessity, somewhat arbitrary. In general those classed as complete include the determination of sulphate, calcium, and magnesium as well as bicar- bonate and chloride. Some of the complete analyses include also con- ductance and/or boron determinations. Many of the partial analyses also include conductance and boron but not the sulphates, calcium, and magnesium. The waters of the Ventura area, both surface and underground, have certain general characteristics in common. These are: (1) rela- tively high proportions of bicarbonate and sulphate; and (2) relatively low sodium percentages, i. e., high calcium and magnesium. This means that a substantial part of the soluble material consists of calcium together with bicarbonate and sulphate. These constituents form salts of such low solubility that the salts are precipitated from the soil solution in the soil before their concenfrations becomes high enough to be injurious to crop plants. The fact that the dominant constituents of these waters form salts of low solubility makes it possible to use successfully for irrigation, waters having much higher total salinity than it woidd be safe to use if the proportions of either sodium or chloride were higher. Boron is found in potentially injurious concentrations in a few wells and springs and particularly in the waters of Piru and Sespe Creeks. Some crop injury from boron has occurred in areas contiguous to these sources of boron contamination. Elsewhere in the area evi- dences of boron injury are either very slight or altogether absent. Recognition of the causes and symptoms of boron injury should make it possible to diminish its extent and seriousness by eliminating some of the sources of contamination, and by so blending the waters of the remaining sources with those of lower boron content as to reduce the boron concentration of the general supply beloAv the limit of tolerance, which for this area is thought to be 0.50 p. p.m. It should be kept in mind that the sulphate constituent is the dominant one in the waters of the Ventura area and that although much of it may be precipitated from solution as calcium sulphate * By Carl S. Scofield, Principal Agriculturist in charge of Division of Western Irrigation Agriculture, U. S. Bureau of Plant Industry. (91) 92 DIVISION OF WATER RESOURCES PLATE XXIII VENTURA COUNTY INVESTIGATION 93 witliout injury to ci'op phints, somo of it may remain in solution as sodium or magnesium sulpluite and tlius become sufficiently concen- trated in the soil solution to be harmful to crop plants. Such concen- tration has occurred in some areas in the Oxnard Plain, and to a limited extent elsewhere in the area. The aggregate quantity of sulphate carried annually to the land in the irrigation water is very large, and consideration should be given to the problem of disposing through drainage outlets of that part of it that is not precipitated in the soil as calcium sulphate. In each of the three drainage subdivisions of the Ventura area there are rather wide ranges of concentration both as to salinity and boron. By far the larger volume of the irrigation Avater is of the intermediate class with the percentage of sodium ranging below 40, the sulphate content ranging from 300 p. p.m. to 800 p. p.m., and the boron content ranging below 0.5 p. p.m. Water of this type appears to be quite safe for general irrigation use with the existing conditions of climate and soil. There are limited supplies of water of lower salinity and also some of higher salinity than this intermediate class. There does not appear to be any evidence that the deeper under- ground waters used for irrigation in the coastal plain sections are more concentrated than those found in some of the upper basins. Nor is there evidence of salt water intrusion to any significant extent along the ocean front of the coastal plain. There is some excessive salinity in the waters found in the subsoil in or just below the root zone in certain areas of the coastal plain, which indicates the need of drainage. The removal of this saline subsoil water is called for not only to protect the productivity of the overlying soil but also to prevent the contamination of the underlying supplies of irrigation water which might occur as the result of temporary or local overdrafts due to excessive pumping from the deeper strata. SURFACE WATERS The area included in the Ventura County investigation involves chiefly the drainage basin of the Santa Clara River together with the basin of Calleguas Creek and its tributaries south of the Santa Clara and the basin of Ventura River, which is west of the Santa Clara. All three streams discharge into the Pacific Ocean across the coastal plain of Ventura County. The boundaries of these drainage basins and the locations of the 98 points at which samples of surface water have been taken for analysis are shown on Plate XXIII. Rincon Creek is a small stream draining the foothills to the west of the drainage area of Ventura River. It was sampled at location 98 in January, 1929. Its water at that time was of low salinity, with low boron and low per cent sodium. The surface waters of Ventura River and its tributaries have been sampled at nine points. The samples from locations 89, 90, 96 and 97 are characteristic of the better surface waters of this area, having low- to intermediate salinity, low boron contents, and low sodium percen- tages. The sample from Wheeler's Hot Springs, location 91, is essen- tially different in character. While its salinity is intermediate (con- ductance 157), its boron content of 6.79 p.p.m. is very high as is its percentage of sodium. Also its chloride content of 241 p.p.m. is very high for that area, while its sulphate content is low. The contrast in 94 DIVISION OF WATER RESOURCES quality between the water of "Wheeler's Hot Springs and that of Matilija Hot Springs is very striking. The salinity of the latter is very low as is the boron content, although the sodium percentage is high. The evidence from the six sampling locations, 90 to 95, shows that while the North Fork of Ventura River above Wheeler's Hot Springs does not contain much boron, it is contaminated with this element from those hot springs. On the other hand, Matilija Creek above Matilija Hot Springs is contaminated with boron, and its concentration is only slightly diluted by the contributions of water from Matilija Hot Springs and from the North Fork, as is shown by the sample from location 95. The samples from Ventura River at Foster Park, location 96, range in conductance from 99.8 to 111, in boron content from 0.41 to 0.52 p. p.m. and in per cent sodium from 9 to 30. While this boron content approaches the lower limit of tolerance, the other characteristics of the river water as sampled at this point are such as to indicate that it is safe for irrigation use. Santa Clara River drains a mountain watershed most of which lies north of the main river channel. This channel is normally dry except at flood time or except at a few points where subsurface barriers force the underflow to the surface. One such subsurface barrier occurs at location 74. The stream flow as sampled at this point, eleven times during a three-year period, has ranged in conductance from 107 to 205, in boron from 0.26 to 0.70 p. p.m., and in per cent sodium from 19 to 50. The water is characteristically high in bicarbonate and sulphates but low in chlorides. The highest salinity and boron occurred in the low summer flow of 1929. The surface waters above this point are represented by samples from five locations, one at the mouth of Soledad Canyon, No. 72 ; three from near the headwaters of San Francisquito Creek; and one, No. 73, from a slough adjacent to the main channel. The samples from loca- tions 1, 2 and 72 are of low salinity and low boron ; those from locations 3 and 73 are of intermediate salinity. There is no evidence of serious boron contamination above location 74 at the Newhall ranch bridge. Shortly below this point the main channel of the river is joined by Piru Creek. This stream is one of the two more important tribu- taries of the Santa Clara. The quality of its contribution is shown by the analyses of 48 samples from location 29, and 11 samples from loca- tion 30, taken during the years 1928 to 1932, inclusive. It will be observed that the discharge at the time of sampling has varied between wide limits and that in general the salinity and the boron content vary inversely as the discharge. The range of conductance is from 51.9 to 363, and of boron content from 0.67 to 3.08 p. p.m. The per cent sodium is generally low as is the chloride content when compared with the bicar- bonate and sulphate concentrations. In general, except during flood periods, the water of Piru Creek contains more than 1.5 p. p.m. of boron, a concentration rather too high for safe use in the irrigation of citrus crops, walnuts, and similar boron-sensitive species. In view of the fact that Piru Creek contributes a substantial part of the water supply of Santa Clara River and that the boron concentra- tion of its water is high, a number of water samples were collected from l)oints along the main stream and from its more important tributaries. The locations of these sampling points, Nos. 4 to 28, inclusive, are shown on the map, Plate XXIII. From these analytical data it is evident that VENTURA COUNTY INVESTIGATION 95 boron contamination is contribnted to the headwaters of the stream by Seymour Creek and Lockwood Creek, both of which drain Lockwood Valley. In this valley and particularly along its north side there are outcrops of boron minerals, chiefly colemanite, which on weathering yield boron salts. However, it is apparent also that not all of the boron found in Pirn Creek is derived from Lockwood Valley. The waters contributed by Agua Blanca Creek and several smaller streams below it also contain relatively high concentrations of boron. In view of the fact that boron and salinity constituents are con- tributed from several different areas within the watershed of Piru Creek, it is not regarded as feasible to improve the quality of its water by attempting to segregate these sources of contamination. Any program of development by which the flood waters of the stream could be con- served by storage would doubtless result in measurable improvement by dilution, but the character of the soil of the watershed is such that even under the best system of water control the annual yield of salinity and boron must be relatively high. There are two small creeks that discharge into the Santa Clara between Piru Creek and Sespe Creek. These are Hopper Creek and Pole Creek, locations 31 to 34, inclusive. The waters of both creeks are relatively high in salinity but not in boron. Sespe Creek, like Piru Creek, drains an extensive area of mountain watershed. The determination of the quality of the water it con- tributes to the main stream is based on the analyses of 50 samples col- lected at location 59 during a period of 4^ years. In general the water of Sespe Creek is less saline than that of Piru Creek and contains much less sulphate. On the other hand, it has higher concentrations of both boron and chloride. Its chloride content is generally well below the limit of tolerance for irrigation use but its boron content, which often ranges above 2.5 p. p.m., is definitely too high for safe use for all but the more boron-tolerant crops. An exploration of Sespe Creek from near its headwaters to its mouth was made in the spring of 1930, locations 35 to 58, inclusive, and 60 and 61. The results of this exploration show that substantially all of the boron is contributed from Willet Warm Springs, location 49, and by Hot Springs Creek, location 51, each having more than 6.0 p. p.m. of boron. If it were found practicable to segregate these spring waters and prevent them from entering the main stream, a very definite improvement in quality should result. It might well be that such segre- gation would reduce the boron content of Sespe Creek water to a con- centration well below the safe limit of tolerance for general irrigation use. The quality of the water contributed by Lord Creek, location 63, is very good. Conditions along Santa Paula Creek are reported for seven loca- tions, Nos. 64 to 70, inclusive. With one exception the waters from these locations are of good quality. The exception is a spring at loca- tion 66. This spring water is high in salinity and in boron, conduct- ance 809, boron 3.58 p. p.m. but the volume of discharge is small. There is a similar spring near the head of Aliso Canyon, location 71, conductance 735, boron 5.76 p. p.m. This latter spring may be respons- ible, in part, for some of the boron injury to be observed in lemons growing on the delta of Aliso Canyon below the spring. 96 DIVISION OP WATER RESOURCES Along the main channel of Santa Clara River samples have been collected from time to time at eight locations, Nos. 75 to 82, inclusive, from Bardsdale bridge, above the junction of Sespe Creek, to Willard bridge below the junction of Santa Paula Creek. Two of these locations represent oil field drains, and the waters are high in salinity, particu- larly in chloride, and contain between 1 and 2 p. p.m. of boron. The samples of river water are generally of intermediate salinity, i.e., con- ductance ranging up to 160, with boron concentrations frequently rang- ing up to 0.8 p. p.m. or slightly higher. Water of this boron concentra- tion is not well suited for irrigation use on lemons or walnuts. In the watershed of Calleguas Creek south of the Santa Clara Valley only one sample of surface water has been reported, that from location 83. This water is of good qualit.y both in respect to salinity and boron. On the coastal plain south of Oxnard samples of drainage water have been collected periodically at locations 84 and 85. These drainage waters probably represent the excess soil solution drawn from the root zone of the soil in saline areas. The total salinity is high, as is also the boron. For purposes of comparison the analysis is reported for a sample of ocean water taken from the beach at location 87. UNDERGROUND WATERS Ventura River Basin^ For convenience in considering the quality of its underground waters the Ventura River Basin is subdivided into three districts: (1) the Ojai Valley, (2) Ventura Valley above Foster Park, and (3) Ven- tura Valley below Foster Park. In the Ojai Valley water samples have been analyzed from ten wells. For irrigation purposes the quality of these waters is very good. The conductance has been reported for only one location, 9-L— 5, for which it ranges from 72.6 to 76.8 ; the boron content ranges from 0.02 to 0.17 p. p.m. except in one case where 0.52 p.p.m. is reported. The per cent sodium ranges from 3 to 40, the chloride from 10 to 95 p.p.m., and the sulphate from 72 to 197 p.p.m. In the Ventura River Valley above Foster Park water samples have been analyzed from eight locations. The ranges in composition are as follows: Conductance (5 only), 110 to 229; boron, O'lO to 1.44 p.p.m.; per cent sodium 7 to 43 ; chloride, 40 to 202 p.p.m. ; and sulphate, 73 to 606 p.p.m. The highest salinity is found at location 7-M-3 and the highest boron contents at 6-K-2 and 6-K-3. Water from the last named two locations is rather too higli in boron for safe use on citrus or walnuts. These wells are located near the head of the valley not far below Wheeler Hot Springs, and their boron contamination may be derived from that source. In the lower Ventura Valley water samples are reported from only two wells. These are both in the lower end of the valley, and the con- centrations are high both in respect to salinity and boron. Their con- centrations are: conductances 331 and 501, boron 1.19 and 1.34 p.p.m., per cent sodium 39 and 44, chloride 620 and 1260 p.p.m., sulphate 510 and 538 p.p.m. These concentrations, particularly the high chlorides, suggest that the underground waters of this lower part of the valley may be contaminated either from the ocean or from adjacent oil fields. These waters are both rather too saline to be safe for irrigation use. * See Plate XLVI in rear pocket. VENTURA COUNTY INVKSTICATIOX 97 Santa Clara River Basin* Tho underground waters of the S;nita Clara River Basin are here placed in six groups as follows: (1) Shallow test wells of the Oxnard Plain; (2) deep wells of the Oxnard Plain; (3) deep wells of the Mon- talvo Basin; (4) deep wells of the Santa Paula Basin; (5) deep wells of the Fillmore Basin; and (6) deep wells of the Piru Basin. The Oxnard Plain has been formed by the deposition of sediments largely derived by erosion from the drainage area of Santa Clara River, although Calleguas Creek has contributed substantially to its southern section. These sediments are somewhat stratified and include beds of sand and gravel, through which water moves easily, interspersed or inter- rupted by strata or barriers of fine silt or of cemented material. These beds of water-bearing sand and gravel are tapped by deep wells and are replenished in part by flood waters from the two streams and in part by subsurface waters moving in a downstream direction along the stream channels. The bedding of the sediments is such that some of the buried gravel strata appear to be connected with the gravels of the stream channels so that replenishment is but slightly impeded, while the alternating beds of fine silt or of cemented material impede normal hydrostatic equilibrium. Thus the waters found in the buried gravels under the lower or coastward areas of the Oxnard Plain are normally under some hydrostatic pressure, and when these are tapped by wells the water rises nearly to or even above the ground surface. The pressure developed and the consequent elevation of the static water levels are influenced by the volume of replenishment from the contributing stream channels and by the volume of withdrawal through the wells. Thus the static levels are markedly high during the late winter and early spring when the rate of replenishment is high and the rate of withdrawal for irrigation is low. These conditions have a direct relationship with a discussion of the quality of the water in the Coastal Plain sediments because the evidence indicates that the water supplies cliietiy drawn upon for irrigation use are derived directly from the contributing streams and are in conse- quence of the same quality. In certain areas of the Oxnard Plain surplus water occurs in the subsoil in or just below the root zone. In general this superficial subsoil water is not connected hydrostatically with the water in the deeper gravels, although there may be some situa- tions in which such connection exists. This superficial subsoil water probably represents the local accumulations of rainfall or of surplus irrigation water rather than the rising of water from the deeper gravels. Analyses were made of water samples from lo of these shallow sub.soil waters of the Oxnard Plain. Because the conductances are not reported for these samples the concentrations of chloride may be taken as the best single measure of salinity. In all the analyses the concen- tration of sulphate is much higher than that of the chlorides. This may be taken as evidence that the salinity found in these waters is due to concentration by evaporation of the terrestrial waters and not to contamination by sea water. If sea water contamination were involved, * See Plate XLV in rear pocket. 7— S367— S375 98 DIVISION OF WATER RESOURCES the cliloride content would be liigher than the siilpliate. Of the 15 samples reported, only four have chloride concentrations below 100 ]).p.m. and only two have sulphate concentrations below 600 p. p.m. Thus it is clear that this superficial watei- is much more saline than the water from the deeper graA'els. Its boron content is also much higher, there being only three samples having less than 1.0 p.p.m. of boron. The difference in quality between the superficial and the deep water is strikingly shown by comparing the analyses of sam])les from adjacent deep and shallow wells, e.g., 6-E-l and 7-R-l ; 7-U-2 and 8-U-18 ; 9-U-l and 9-U-45. These are shown in the following table : TABLE 19 COMPARISON OF SUPERFICIAL AND DEEP WATER IN OXNARD PLAIN (Constituents in parts per million) Adjacent wells Deep Shallow Deep Shallow Deep Shallow 6-R-l 7-R-l 7-r-2 8-U-18 9-U-l 9-U-45 K X 10' at 25° c of c 122 0.64 232 35 414 127 36 95 125 53 241 39 405 120 44 88 2.94 740 1,542 4,444 680 616 1,468 5.06 220 867 1,890 256 344 610 2.33 Bicarbonate HCO», Carbonate 00= Chloride CI 331 51 382 365 Sulphate SO' 2,280 352 187 716 Analyses were made of samples collected from deep wells located in the lower part of the Oxnard Plain in what is regarded as the "pres- sure area," i.e.. the area in which the deeper water is under such hydro- static pressure as to rise in the wells nearly to or above the ground surface. This area lies between the coast and the main highway between Ventura and Camarillo. In this area 55 wells have been sampled for analyses. The water samples from 45 of these wells are remarkably uniform in quality, having conductances ranging from 100 to 160 ; boron from 0.3 to 0.6 p.p.m. ; per cent sodium from 30 to 10 ; chlorides from 50 to 65 p.p.m. ; and sulphates from 300 to 600 p.p.m. In view of the fact that the irrigation wells located in the "pres- sure area" of the Oxnard Plain draw water from gravel strata that lie well below present sea level, it might be suspected that contamination by sea water would occur in some of them. Of the 55 Avells within this area that have been sampled, 18 are located within one mile of the beach. Only two of these. 9-W-2 and.ll-X-1, show definite evidence of sea water contamination. Five others, although located within a few hundred feet of the beach, appear to be as free from such con- tamination as any of the wells within the area. One other well within the one-mile zone, lO-W-8, is slightly saline but the evidence of sea water contamination is not convincing. There are seven wells located near the foothills in quadrangles 12-W, 13-U and 13-V that are defi- nitely more saline than those farther out in the plain or nearer the beach. VENTURA COUNTY INVESTIGATION 99 Montalvo Basin The Montalvo Basin includes the upper part of the delta of the Santa Clara River between Saticoy and the State highway. It is recog- nized as a ''noupressnre area" becanse the hydrostatic pressure on its \indergronnd waters is not great enough to lift these waters through the wells to the gronnd surface. Within this area 21 wells have been sampled and analyzed, some of them repeatedly. The results of these analyses indicate that the quality of the underground water in the Montalvo Basin is substantially the same as that in the deeper gravels of the Oxnard Plain in the "pressure area." The inference is that there is direct water connection through the Montalvo Basin from the underflow of the Santa Clara River to the gravel strata in the sediments of the Oxnard Plain. In general the water found in the 21 wells sampled in this basin would be classed as of intermediate salinity, with the boron content ranging around 0.5 p. p.m. Three of the wells, 8-R^6, 8-S-6, and 10-R-ll, have rather high sulphate contents, but in view of the low sodium percentage these concentrations should not cause serious concern. Santa Paula Basin The Santa Paula Basin includes that section of the river valley below Santa Paula Creek extending to the Montalvo Basin. The arable land in this section is devoted largely to citrus and walnuts and is highly developed. It is irrigated mostly with local underground waters. These waters as sampled from 61 wells show rather more diversity in quality than is found in the wells of the Oxnard Plain. Four of them are located in the canyons north of the main valley. One of these four, lO-O-l, is a shallow well in Wheeler Canyon wdth high salinity and high boron. Two others, 10-P-l and 2, are located on the west side of Aliso Canyon. Both are of intermediate salinity, one with low boron and the other with an intermediate boron con- tent, 0.87 p. p.m. The fourth of these foothill wells. No. 11-0-1, is of low salinity Avith boron not reported. The three wells adjacent to Telegraph Road west of Wells Road have concentrations similar to those of the better w^ells in the Montalvo Basin. The two wells adjacent to Wells Road south of Telegraph Road, lO-Q-9-9 and lO-R-6, are rather more saline, as are also the two wells near the intersection of Olive Road with Tele- graph Road, lO-Q-3 and 6. and the two near the intersection of Cummings Road and Middle Road, ll-P-2 and 9. Another saline well is found at ll-P-13 south of Middle Road and east of Briggs Road, and still another near the lower end of the area, lO-R-22. With these exceptions the underground waters of this basin tend to range lower in salinity than those of the Montalvo Basin. This is particularly true of a number of wells located on the upper part of the delta of Santa Paula Creek in quadrangles 12-0 and 13-0. The wells of this grou]i are not only low in salinity but in boron also. The wells located in the vicinity of Santa Paula show the beneficial effects of the fresher water contributed from Santa Paula Creek as compared with that occurring in the gravels of the main river channel. In general also the deeper wells appear to yield somewhat better water. 100 DIVISIOX OF WATER RESOURCES Fillmore Basin The wells in this basin are located on both sides of the Santa Clara River from the junction of Sespe down to Santa Paula Creek. There are 54 of these wells for which the analyses were made. This basin includes the delta of Sespe Creek and in consequence some of the wells near that delta in (juadrangles 16-X and 16-0 have boron concentra- tions ranging up to 1.00 p. p.m. or higher. On the other hand, there are a number of wells contiguous to and north of the main highway west of Hall Road that have the lowest concentrations of salinity and of boron found in the whole valley. Wells in this section of the basin between the railroad and the river are slightly more saline and contain somewhat more boron. Wells at 14-0-16 and at 15-X— 5 are somewhat anomalous in that they have much higher concentrations of sulphate than neighboring wells, while the well at 16-M-2. in whieli the salinity is low, has an abnormally high boron content. In general the wells of this basin south of the river in the vicinity of Bardsdale have higher salinity than those north of the river, and some of them also have relatively high boron contents. It seems prob- able that the boron contamination occurs throug:h strata of gravel con- necting under the river witli Sespe Creek. Piru Basin The Piru Basin includes the section of the Santa Clara River Valley above the delta of Sespe Creek. Within that basin 25 wells have been sampled. In general the wells of this basin are located not far from the river channel because the valley is narrow in this section. The waters are, for the most part, more saline than those of the Fill- more Basin, particularly are they hig:her in sulphates. The boron content ranges rather high also, only one well having a boron content as low as 0.35 p. p.m. and range up nearly to 1.5 p. p.m. The higher sulphate concentrations occur at locations 18— N— 13, 19-N-l. 19-X-18 and 20-X-ll. These higher concentrations of boron and sulphate doubtless reflect the influence of Piru Creek waters, which are notably high in these constituents. There may be some local sources of sulphate contamina- tion in the buried sediments, but it seems probable that Piru Creek is the chief source. REVIEW OF THE SANTA CLARA RIVER VALLEY Underground Waters By way of review of the observations noted in the preceding: paragraphs it may be pointed out that in the underground waters of the Santa Clara Valley there is not a prog:ressive increase in salinity in the downstream direction. The wells in the Piru Basin j'ield waters that are, if anythiufr. slightly more saline and in general rather higher in boron than the wells of the ]\Iontalvo Basin and the Oxnard Plain. This is a condition not usually found along streams that are extensively used for irrigation. The usual condition is that salinity increases in the downstream direction because the return flow from irrigated lands is more concentrated than the Avater applied as irrigation. VENTURA COUNTY TNVESTIOATIOW 101 Til the case of tlio Santa Clara IJivcr most oi' tlic sulpliate salinity and niiii'li of the hoi-on is eontrihuted from Pirn Creek, while Sespe Creek contributes chiefly boron and chloride. The flood waters of both streams are nmch less saline than the low -water flow, and it is these flood Avaters that larofely replenish the underground supplies in the lower basins. The contributions of JSanta Paula Creek and of several of the smaller streams are also much less saline and lower in boron content than those of Sespe antl Pirn Creeks; conse(|ueutly, the local underfiii during 1915 to 1920. In other words 8367 — 8375 — p PLATE XXIV 1895 1900 1 , 1905 1 1 1 1910 1 1 1915 1 1 1 . p-, 1920 [ — 1 , 1 1 1925 1 — 1 — . . — , 930 1 j 1 =^ =r^ t= Full 1 bas ^■z*-- n^ \ 1 / k ^ /: ^ z ~~ - ^ ^ L -Tf(^ \ / \, / PIRU BASIN N /-^ d /N / s N / / N / >. 1 V :\ ^ ^ ■•-- -~~ ^ /y 4- 1 1 1 1 1 1 4- \ / V. Fi jII b asin ^ h ^ ^ ^ ^ \. y ^ ■^ [^ ^ /'^^ \ / ra o 60 ^ ^ / / \ 1 III' FILLMORE BASIN ~~- ~--'' \\ N / \/ ^-., ■-^ / 1 1 1 1 1 S /' — - .' SANTA PAULA BASIN VARIATION IN STORAGE WITHOUT CONSERVATION SANTA CLARA RIVER BASINS Present use.fall storage Ultimate use, fall storage • Years in which basin is full in spring years Pi™ FUlmor^ fnrt 4»nt= c,, . 'V"'*^"' '",i^^ 'f-' I'^hen it is at the lowest for the year. It is at the highest in the spring and in some St on each b2l^n^frrt rr^^i^.J^'^V^^^^ ^^ '"" '" ^^^ spring. These years are shown by dots on the lines marked "Full Basin." The dry ye^rl Tlif d?aft wn^.^^^'i^l^'^,*'^^^^ '" T'^'^'" content is based on that found during the investigation which covered one wet and four wo^rd^st't'h'e cJlc'ula^TiSoTg^'tLrst^rSg^^Jlry^ AStTc'tualf; e'xis'"''' ^'"'■^ ""'' '' ^° °"""'''* ^""" ""^''' "" ''"""^ '"' '° ^''''- '" °""^ 8367 — S375 — pages 106-107 VENTURA COUNTY INVESTIGATION 107 fall lows of each year of the 4()-year period under discussion and with the assumption that the area irri^'ated in 1982 -svas irrinat('(l as "irrigable or habitable" on Plate XLVIII, in rear pocket of report, is 24,800 acres. Apiiroximatelj^ 6300 acres of valley floor are now iisinp^ water. l-'^OO acres are in roads, barrancas, etc., which are not irrigable and 4500 acres may be regarded as irrigable from a topographic stand- ])oint. On the hills 690 acres are now irrigated. It is assumed that 75 i)er cent of the remaining irrigable valley lands or 3400 acres and 25 per cent of the remaining hill lands or 6200 acres might some day use water if it were available at reasonable cost.* Water Supply This is derived in small part from percolation of rainfall on the valley floor to the underlying water table. The average rainfall for the 40-year period beginning fall 1892 is estimated at 13.9 inches and for the eleven years beginning fall 1921 at 12.5 inches. The estimated annual deep percolation for the 40-year period is about 1600 acre-feet. Percolation from streams entering the valley is a minor source of replenishment to the underground basin. These streams are small and flow only occasionally. Surface outflow from the valley is small except in occasional years of heavy precipitation. A portion of this comes from Sinii Basin above and that originating in Las Posas Basin may not average more than 500 acre-feet per year. The total watershed area above the valley' floor is 40,400 acres or about 63 square miles. Practically the entire area is the Saugus forma- tion with overlying areas of terrace gravel on the northern shed. The Saugus formation extends across the valley beneath the late alluvials of the valley floor. Both terrace gravel and Saugus formation are l)orous and absorb the rainfall upon them, and the formation allows the water thus absorbed to be conducted beneath the valley floor where it is within reach of pumps. The average rainfall on the watershed is slightly more than 15 inches. No reliable evaluation of the supply to the valley from this source is possible but it is believed to be large. Xo attempt is made to evaluate the total water supply. Use of Water The duty of water is about 1.33 acre-feet per acre for citrus groves, about 1.86 acre-feet for deciduous trees and about 1.30 acre- feet for beans. The estimated consumption of irrigation water for the 6300 acres now irrigated is about 8400 acre-feet. In addition, about 3600 acre-feet are exported to West Las Posas Valley and about 700 acre-feet to Pleasant Valley. Surplus or Shortage During the period of investigation water levels dropped somewhat over the entire valley except from fall 1931 to fall 1932. During the first four years precipitation was subnormal and in winter 1931-32 was about 20 per cent above normal. In the period between fall 1931 and fall 1932 the general water level neither fell nor rose. Conclusion It is probable that recharge from deep percolation in the mountains during the winter had not made itself felt entirely by the fall of 1932 * Compare with table on page 220. 132 DIVISION OF WATER RESOURCES since the time ol' 1i'a\'cl siiould he lon<>'. Xotiiiii"' very deiinite is indi- luited but it is believed that water sup])ly over the long-time average is sufficient for present acreage and exportation but conclusion can not be made as to whether supplies are sufficient for much additional draft. WEST LAS POSAS VALLEY This basin is bounded on the south by Camarillo Hills, on the north by South Mountain, on the east by the low topographic divide between it and Las Posas Valley, and on the west it merges into the Oxnard Plain, but the dividing line is marked by a slope somewhat more steep than the terrain either to the east or west. As is general in Calleguas Creek Basin, the boundary between hills and valley is not definite. This valley does not drain into Calleguas Creek, but is discussed under that general heading for convenience. Its surface waters debouch onto the Oxnard Plain and are dissipated before arriving at any major drainage channel. The water table slopes from Las Posas Valley entirely through West Las Posas Valley toward Oxnard Plain. There is no hydrographic divide between the two. The total area of valley floor is 6200 acres. The area of hills around the margin of the valley designated "irrigable or habitable" on Plate XLVIl, in rear pocket of report, is 3700 acres. Approximately 4200 net acres of valley floor are now using water, 300 acres are in roads, barrancas, etc., which are not irrigable and 1700 acres may be regarded as irrigable from a topograj)hic standpoint. On the hills 110 acres are now irrigated. It is assumed that 75 per cent of the remaining valley irrigable lands or 1300 acres and 25 per cent of the remaining hill lands or 900 acres may some day use water if it were available at a reasonable price.* Water Supply Wells driven in this area give unsatisfactory yields and most of the w^ater used is imported from Las Posas Valley and from Oxnard Plain. That from Las Posas Valley has averaged 3600 acre-feet for the past 10 years. The only source of local supply is deep percolation from rainfall on the valley floor and contribution from local water- sheds, believed to ap])roximate about 1200 acre-feet for the forty-year average rainfall of 14 inches. AVith ]iresent conditions this goes in large part to the underground supply of Oxnard Plain. Conclusion Water supjily depends on suiijily of Las Posas Valley already discussed, and of the Oxnard Plain. SANTA ROSA VALLEY The area below the rather indefinite line between hills and valley" floor is 8300 acres. The area of hills around the margin of the valley marked "irrigable or habitable" on Plate XLVII, in rear pocket, is 12,900 acres. Approximately 2550 net acres of valley floor are now using water, LSO acres are in roads, barrancas, etc., whicii are nonirri- gable and 5500 acres may be regarded as irrigable from a topographic standpoint. On the hills 1020 acres are now irrigated. It is assumed * Compare with table on pase 220. VENTURA COUNTY INVESTIGATION' 113 that 75 per cent of tlic i-emniniiit;' valley lands or 41()0 acres and 25 per cent of the remaining;- hill lands or 8()()() acres may use water at some future time if it b(Y'omes available at i-easonable cost.* Water Supply This is derived in part from percolation of rainfall on the valley floor to the underlying water table. The forty-year average rainfall on the valley floor is estimated at 13 inches and for the eleven years beginning fall 1921 at 12 inches. The estimated annnal deep percola- tion for the 40-year period probably does not exceed 1000 acre-feet. Percolation from the streams entering the basin is small in amount and it is thought that the outflow from the valley does not exceed 300 acre- feet on the average as it occurs only occasionally. If so, most of the rainfall on the watershed and valley floor is retained. The total watershed area above the valley floor is 32,900 acres or about 50 square miles. The small watershed to the north is sufficiently porons to allow deep penetration of rainfall on it. That to the south is basaltic but it is not as porous as it is to the east above Simi Yallej'. The average rainfall on the watershed south of Santa Rosa Valley is abont l-t inches and it is believed that the valley receives the major ])ortion of its supply from rain on this area which has percolated into the fissures of the rocks and finally reaches the valley. No reliable evaluation of this or of the total water supply can be made. Use of Water Xo data on duty of water are available, but it may be assumed similar to Las Posas Valley. The important factor is water consumed rather than that applied and this is assumed the same as for Las Posas Valley. The estimated consumption of present crops is about 4200 acre-feet. Surplus or Shortage During the five years of the investigation there was little change in water levels at the wells measured although rainfall in the first four years was subnormal and in the last year above normal. This indicates a distant source of supply fed gradually to the valley. Conclusion No evaluation of water supply can be made, but from behavior of wells, it is calculated that it is sufficient for present draft. If the watershed to the south is fairly absorptive there may be water for addi- tional acreage. PLEASANT VALLEY Pleasant Valley is an arm of the Oxnard Plain extending eastAvard. There is no boundary between it and the Oxnard Plain either on the surface or by definite underground structures. The boundary selected is believed to approximate the eastern limit of the wanderings of Santa Clara River as it built the Oxnard Plain. It does not appear possible that the river could ever have flowed further to the east. Well logs to * Compare witli table on page 220. S — 8367 — 8375 114 DIVISION OF WATER RESOURCES tlie west of the line shown as tlie boundary "ive much larger quantities of sand than do those to the east in Avhich tight material predominates. The boundary is shown by a dotted line on Plate I. To the east of the line of small dots on the plate, the underground waters are not under pressure and to the west they are. Pressure level in that portion to the west of the line is different from that of the Oxnard Plain. The Saugus formation underlies most of Pleasant Val- ley and many wells are drilled into it. Wells in Oxnard Plain do not penetrate this formation. The total area of the valley floor is 22,000 acres. There are about 1500 acres of hills marked "irrigable or habitable" on Plate XLVII in rear pocket. Approximately 15,100 acres of valley floor are now using water, 600 acres are in roads, barrancas, etc., which are not irrigable and 6300 acres may be regarded as irrigable from a topographic stand- point. It is assumed that 50 per cent of the remaining valley lands or 3200 acres and 25 per cent of the remaining hill lands or 300 acres may use water at some future time if it is available at reasonable prices.* Water Supply This is derived in part from percolation of rainfall on the valley floor to the underlying water table. The forty-year average rainfall on the valley floor is about 13 inches and for the 11-year period begin- ning 1921 about 11 inches. The estimated deep percolation on the non- pressure area for the 40-year period probably does not exceed 2000 acre-feet per annum. Percolation from the streams entering the valley is small. About 700 acre-feet per annum are imported from Las Posas Valley. Total watershed area above the valley floor is 1300 acres or about 21 square miles. Most of this is to the south and consists of intruded basalts. Hence, the watershed is less fissured here than further east. The estimated rainfall on the watershed is only 13 inches which would give no very large deep percolation later available to the valley even if the formation is open enough to allow it. The remaining small portion of the watershed is Saugus formation, but the supply to the valley from it must be insignificant. No reliable evaluation of total water supply can be made. Use of Water The estimated consumption of irrigation water for the area now irrigated is 16,500 acre-feet annually. Surplus or Shortage Water levels over the entire area dropped during the period of investigation but from fall 1931 to fall 1932 were stationary on the average. Precipitation was subnormal in the first four j^ears, but in winter 1931-32 was 15 per cent above the estimated normal. Conclusion It is thought that the underground supply may be overdrawn but the extent of overdraft, if it exists, is not estimated. * Compare with table on page 220. CHAPTER X WATER SUPPLY OF COASTAL PLAIN The term Coastal Plain as used in this report includes the city of Ventura, the Montalvo area and the Oxnard Plain. The city of Ventura is supplied by Avater from Ventura River and this matter is discussed in Chapter XIV under the heading of Ventura River. Most of tlie Oxnard Plain and the Montalvo area derive water supply naturally from Santa Clara River, and this is the principal source, but above the approximate line north of Santa Clara River labeled "Assumed Limit of Influence of Santa Clara River" on Plate I, the natural supply is from the north and is insufficient and in some places of i)oor quality. Therefore water is secured by pumping south of the line and conducting it to the area to the north, making this area also de])endent on Santa Clara River. The location of the above line is governed by the two small mounds of terrace gravel which obtrude from the plain near Montalvo, the yield and location of wells and the contours of the water table. The contours indicate that the water to the north of the line must come from the north, while to the south of the line well logs and contours indicate water probably comes from the river. The location of the eastern boundary of the Coastal Plain is also at what is believed to be the approximate limit of influence of the river as disclosed by well logs. In addition there is a rise in the ground surface which indicates the division between West Las Posas Basin and Montalvo area. Surface indications are entirely lacking at the boundary between Pleasant Valley and Oxnard Plain. Eliminating the city of Ventura, the total area of Coastal Plain as thus delimited approximates 65,700 acres. Of this, 43,600 acres are now using water, and 8900 acres are in river wash, roads, etc., and will not use water in the future. From a topographic standpoint approximately 10,000 acres may be regarded as irrigable. The larger ])ortion of this is in the extreme southern corner where Calleguas Creek discharges into the ocean and here the soil is sour and salty so that it will be difficult to reclaim. In addition to the land on the valley floor, 130 acres of tributary hill land are irrigated and approximately 1550 acres are classed as "irrigable or habitable." Most of this lies in the hills to the north. As a basis for water supply calculations, it is assumed that about 5400 acres additional land will come under irrigation.* Use of Water Principal crops are beans, beets, alfalfa and truck. Citrus is gradually assuming greater imj)ortance. The climate is cool and foggy and water used per acre is small. Based on records secured in various parts of the area, the average use in north Montalvo and Oxnard areas * Compare with table on page 220. ( 115 ) 116 DIVISION OF WATER RESOURCES is 1.08 acre-feet per acre i)er year, in soutli Montalvo area 1.08 and in Oxnard Plain 0.82. The averaj?e use over the entire area is estimated at 0.90 acre-feet per acre per year. The water table is under pressure over a large part of the area and deep percolation from irrigation can not reach the water table, hence the gross draft is the draft on the underground water but this is not true of the Montalvo area. The surplus water from irrigation in the pressure area penetrates to the surface ground water which is highly impregnated with salts and can not be used. This is removed by surface drains into the ocean. Citrus trees use more water than beans, beets or truck and if groves replace these crops the draft will be increased. However, the use by citrus is estimated at only 1.00 acre-foot in the Oxnard Plain. Water Supply The principal supply is underflow from Santa Clara Valley and percolation in the river bed in crossing the absorbent Montalvo area. Next in importance is rainfall penetration on the Montalvo area and West Las Posas area, and next, percolation of run-off from the northern mountains. Other miscellaneous small supplies were neglected in calculations. Analysis of the supply to and demand on this area was made for the 40-year period beginning with fall of 1892 on the aSvSumption that all the land presently irrigated in Santa Clara Valley had been irri- gated during the period thereby decreasing the historical supply, and that all the land presently irrigated in the Coastal Plain had been irrigated during the period thereby increasing the historical draft, and that the draft during wet years would be the same per acre irrigated as during the period of investigation. The underground basin was treated as a reservoir. On Plate XXIV the changes of content are shown graphically. Starting with the reservoir full this shows a hypothetical decrease in content of 257,000 acre-feet during the period. It should be stated, however, that it is unlikely that the draft would be as large during normal or above normal years of rain- fall as it averaged during the investigation in which four of the five years were years of drought. If this supposition proves to be correct the foregoing estimate of decrease and calculated shortage in the fol- lowing table are too large. The result of tlie calculations is summarized in the following table. TABLE 22 COASTAL PLAIN Present Average Annual Supply and Demand Spring 1812. to Fall, 1932 Supply— Acre-feet Percolation in Santa Clara River across Montalvo Area 22,700 Underflow from Santa Clara Valley 5,000 Rainfall penetration in Montalvo and Los Posas Areas 5,400 Imported from Santa Paula Basin _ _ , 700 ■ 3.S,800 Demand- Agriculture, 42.400 acres at 0.90 38.200 Domestic— 1,200 acres at 150 (Oxnard) 1,800 70 acres at 1.20 (Hueneme) 100 ■ 40,100 Shortage. 6,300 ^ VENTURA COUNTY INVESTIGATION 117 The "shortage" is the average annual decrease in content of the underground reservoir through two periotls of deficient rainfall and one of surplus. Obviously the average shortage is some lesser quantity ; i.e., the loss over a period embracing one wet and only one dry period. The 25-year period from 1893 to 1918 completed a wet and dry cycle and the shortage for that period is estimated to average 1800 acre-feet annually instead of the 6800 acre-feet as shown by the tabulation. In other words over a long period and with present conditions these estimates indicate practically a balance between supply and demand in the Oxnard Plain. If a shortage exists it is api)arently small and might be made up by decrease in draft during wet years, or for the present draft could be readily taken care of at a small expense, but additional draft as new acreage is developed would require more expen- sive development of conservation. However, the underground supply of the plain may be jeopardized by intrusion of salt water from the ocean as the water table lowers during the long dry cycles such as that existing at present. Marine Intrusion If draft had been as great during the past forty years as it was during the investigation the water table would now be at a considerable distance below^ sea level over most of Oxnard Plain. Whether this would allow intrusion of water from the ocean into the pumping strata is not known. It would depend on how low the water table fell and on whether the strata are blanketed off shore with sufficient tight material to prevent inflow. In some places in the State where the water table is below sea level, intrusion has occurred and in some others it has not. It is believed that it constitutes a threat which should be guarded against by artificial replenishment of the basin during the dry period. If sufficient recharge is made during such periods, it can be safely assumed that the long-time shortage will be provided for. The water table slopes from the end of South Mountain w^est and south to the sea. To maintain it at a -gradient toward the shore line it was assumed that the total content above sea level must not be allowed to fall below 6000 acre-feet. The total reserv^oir content between sea level and ' ' Full reservoir ' ' as shown on Plate XXIV, oppo- site page 106, is calculated to be 91,000 acre-feet, leaving 85,000 acre- feet of net safe reservoir capacity. It is possible that the water table could be drawn somewhat below the arbitrarily selected level for periods of a few years without detrimental results. Reference to Plate XXIV indicates that for present draft, during the dry period since 1922 there would have been an average of 9000 acre-feet of artificial recharge per annum required to maintain the water table at the level at Avhich it is assumed that intrusion of salt water would be prevented. Maintenance at this level would result in overcharge of the basin during the wet periods or in waste of water which would have otherwise percolated during such periods. Ultimate development of 5400 acres additional w'ould require, at the assumed net use of .90 acre-feet per acre, about oCKJO acre-feet addi- tional per year. Ultimate development in Santa Clara Valley would demand 11,000 acre-feet per year in addition to present demand. It is true that this additional demand in Santa Clara Vallev would 1 18 DIVISION OF WATER RESOURCES result in 11,000 acre-feet less waste into the ocean on the average but this decrease would largely be made up by increased natural percola- tion of floods so that the net result of ultimate development in Santa Clara Valley and Coastal Plain would be, it is calculated, a need of an auxiliary supply to the Coastal Plain averging 17,000 acre-feet per annum for the years of the dry cycle since 1922 to maintain a pressure gradient to the ocean and exclude ocean water. Conclusion Recharge of the underground water supply of the Coastal Plain is slightly deficient over a 40-year period such as that since 1892, for a draft such as occurred during the dry years of the investigation. If such a period repeats itself and draft continues at that rate per acre the water table would be considerably below sea level at the end of the period. It is estimated that with such a draft it would require an average additional annual recharge of 9000 acre-feet at the present time to sustain the water table during dry cycles and that there will be eventually required an average annual augmented recharge of 17,000 acre-feet to guard against possibility of marine intrusion. If this is taken care of the shortage will be provided for -^vith considerable margin. CHAPTER XI COST ESTIMATES OF SURFACE RESERVOIRS In this chapter are g-iven the results of geological and topographi- cal surveys on the more favorable reservoir sites in the area investi- gated, together with the results of estimates of cost for various reservoir capacities and types of dams at each site. Locations of reservoirs are given on frontispiece. Exploration at the sites has been much more thorough on Piiii Creek than is usual in investigations of this nature because of the controversy caused by occupancy of Los Alamos and Spring Creek sites by the State highway which has brought about a desire to determine whether additional costs for conservation will be incurred due to this occupancy. As Sespe Creek sites offer an alternate con- servation to Piru Creek sites these were also estimated in similar detail but as geological reports indicated simple foundation conditions at the dam sites on Sespe Creek the foundations were not explored. No exploration was done on Matilija site in the Ventura River system but at Dunshee site on Coyote Creek, also a tributary to Ventura River, the abutments were trenched. It is believed that the excavation in the bottom can be fairly approximated from this. At Camarillo site on Conejo Creek borings were made. On Plates XXV and XXVI are curves giving total cost and cost per acre-foot of capacity of various types and capacities, wdiich sum- marize graphically all the information as to cost given in this chapter. Accompanying the description of each reservoir is a plate showing the general layout of one height of the most economic type of dam on wliich detailed estimates are based. In Chapter XIII the cost per acre-foot of yield is given which, as all dams are considered safe, is the idtimate criterion of comparative desirability. Los Alamos Reservoir Los Alamos Reservoir site is located on Piru Creek in Sec. 3, T. 6 N., R. 18 W., and Sees. 27, 33 and 34, T. 7 N., R. 18 W., S. B. B. and M. in Los Angeles County. The dam site for the reservoir is located in the N.E. J of Sec. 3 about 400 feet south of the north line of the section. A topographic survey of the reservoir site was made by the State in March, 1933, and a map was drawn from this survey at a scale of one inch equals 400 feet, with a contour interval of 10 feet. The water surface areas measured from this map and the cai)acities of the reser- voir computed from them are shown in the following table : ( 119 ) 120 DIVISION OF WATER PESOURCES PIRATE XXV co U 2 COMPARATIVE TOTAL OF RESERVOIRS 1 2 3 4 5 6 7 Total cost in millions of dollars \ < \ \ >S •^ ^ \ \ -*1 i c w C \ \, V D.(U 1^1 N \ Jr> -^ \\ \ \ ^_ c c c Si C 1) ^ \ ^ £-5 0-5 1:° 1^ J^ M ' .Et) O c O t>0 in £ •» li; -a c -a o J2 1- ^0 > ! \ 13 c c si ^ "III " 1 O u V— ■D 0-' ^ J) s _ 1. tl ' 3 ni 0) Q- — ^ - e n !. 1 5§ c c D C D U D C 3 c 4.93J-9JDB J.0 spuesnoq; ui X;pBdE3 VENTURA COUNTY INVESTIGATION 121 TABLE 23 AREAS AND CAPACITIES OF LOS ALAMOS RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir. in feet, U. S. G. S. datum in acres in acre-feet 2,270 2,280 1 6 2,290 8 50 2,300 19 178 2.310 39 468 2,320 05 990 2.330 96 1.790 2.340 127 2.910 2,350 156 4,320 2,360 188 6.050 2.370 218 8,090 2,380 249 10,400 2,390 282 13.100 2,400 316 16,100 2,410 348 19.400 2,420 373 23.000 2,430 403 26.900 2,440 430 31,000 2,450 463 35,500 The survey of the dam site was made by the State in April, 1933. A topographic map drawn from this survey at a scale of one inch equals 50 feet, with a contour interval of 10 feet, was used in laying out and estimating the costs of dams of several heights. The geology of the region and the dam site has been studied by Dr. Charles P. Berkey and Paul F. Kerr, Hyde Forbes, and Chester j\Iarliave. Exploration at the dam site consists of drilling six holes in the stream channel to determine the depth of gravel fill and character of the underlying rock. The following data on the geology of the reservoir and dam site are taken from a report by Chester Marliave : The region in tlie vicinity of the Los Alamos Dam site is composed almost entirely of sedimentary deposits of Tertiary age. Thick beds of siliceous and clay shales predominate with lesser amounts of inter- bedded sandstone. There are some major faults in the region, and the sediments for the most part are inclined at rather steep angles. The geology at the dam site has been carefully examined and measurements of dip and strike noted, as well as the character of the outcrops and amounts of loose overburden. The constriction in the canyon that was examined is about 1200 feet in length. Along this stretch there are several locations that are topographically suitable for the construction of a dam. The bedrock throughout this portion of the canyon is a thickly lami- nated, thin bedded, siliceous shale, all dipping uniformly upstream at about 50 degrees from the horizontal with the beds crossing the stream at various angles depending upon the course of the canyon. The rock is hard and slaty, the laminations for the most part varying between ^ inch and 6 inches in thickness. In several horizons the shales are thin bedded and weather on the surface to dark colored finely di^'ided particles, but for the most part the beds of shale have strata averaging several inches in thickness. Interspersed through the bed- ding are several strata of calcareous sandstone whicli generally occur in single layers, seldom over 12 inches in thickness. The fractured condition of the shale upon exposure to the elements is one of the poor qualities of the formation. Where the beds are 122 DIVISION OP WATER RESOURCES PLlATE XXVI ' 8 1 1 e E 1 1 tn i£ fc p *3 T3 L.-5 e sf o°t UJ - t: S"- / s // cc s c 5i •- ° S 0) > ?c ~ llJ l/> UJ 1- ig" / O Si — c // / o o .9 -i: IT o UJ O 1/1 '"o Q_ -^ CM o o i < D 1> s:p UJ o x""// / QJ *> C UJ to < □ oi > UJ r' J # — 1— QC 1 / jy O a ra < u. O / / UJ 1- ^ /i 7 O z 2 o o //^ O / / / o / // w r4 j: = / // •- f o o dr / // 2^ /^ ^ -2.1- ^ k ' / -OS / " 1 •"I ^ \ / / ^K- /rr 4) / / 1 _ro / h = U Q.(U / / f tfi 1- / ^ Q. nj > \ y // il- 1 \ -?, 3 = 1 >1 / ls // §8. o ^ o "oJ ->- — ' / ^ / 1 T r ro / \/ 1 / ^ y f y 1 / >^ a> ^ / J / L / ^ O JJ u y / > n l^ ■o O^ / / / r ^w^ ^^ / r^ / , 1 _C u-^*^ / . / 1 1 < CL - ^ •^ tr^ /I 1^ ^ ^<i- " > o ^^ i? CL ."^ bO i ^^ — -s s ^ / l-^*"^*^ ti „ * / ' «— ■ _l u? a y ^ i .?§ 1 / ^ ^ • ^ Q- ^ ' \ m Q- ^y/ \ S •" = ^ c "53 ^ i o c ^_y^ fa. -* o _,0^ — ^^ - P -s c ^ > -o " ill _g ^^ f 1 5:« 11-% J e nl £ *- / ■ \ 5 " ^' o ^■^ -^ ° o o o o o o o o o ravity concrete dam would require a large section since it would be necessary to design it for uplift over the entire base. There is also some doubt if sufficient aggregates for the amount of concrete required for this type of dam are available in the reservoir site. The site is well adapted to the slab and buttress type of dam and there is sufficient aggregate available in the reservoir site for its construction. This type was therefore selected for com- parative cost estimates. The lavout for a 135 foot dam is shown on Plate XXVIT. The crest line of the dam Avould be about 400 feet south of the township line between Twps. 6 and 7 N. In this location the dam would be below the prominent outcropping strata and on relatively uniform topography. The dam would be straight in plan and the l)()rtion over the present stream bed would be of the overflow spillway type. This spillway section would be 180 feet in length and its crest would be 20 feet below the top of the other portions of the dam. With this length of si)illway it is estimated that a flood of 61,000 second-feet, the crest flow of a flood which may occur once in 1000 years on the average, would pass . the dam without over-topping the nonoverflow sections. No gates would be placed in the spillway and the normal water surface would therefore be at the elevation of the spilhvay crest. The nonoverflow sections of the dam would have crest widths of 12 feet. The upstream face of the dam would have a slope of approxi- mately 1 :1 and the downstream side of the buttresses, except under the spillway, would be vertical for 48 feet from the top and then have a slope of :f :1. The downstream face of the spillway section would be a concrete slab on a slope of | :1. At the intersection of this slab with the stream bed there would be a concrete bucket, and downstream from til is bucket the stream channel would be paved with 2 feet of concrete t(^ a point about 85 feet from the toes of the buttresses. The buttresses would be spaced at 18-foot centers. They would be 18 inches thick at the top and increase 4 inches in thickness in each 12 feet of depth. They would be stiffened by 18-inch by 24-inch horizontal concrete struts at about 24-foot centers in both vertical and horizontal directions. The upstream slab would be 15 inches thick at the top and increase 82 inches in tliickness in each 12-foot deptli of dam. The downstream slab of the spillway would be 18 inches thick throughout. A guide w^all 10 feet high and 3 feet thick would be constructed along each side of the spillway on the downstream side. There would be two 36-inch steel outlet pipes through the dam. Each of these outlets would be equipped with a slide gate near the upstream face of the dam and a needle valve, for regulating the flow, would be })laced at the outlet end. There are in the reservoir site a number of improvements which would be flooded by the con.struction of a dam. These comprise a steel tower transmission line, 26-inch and 22-inch gas pipe lines, an 8- inch oil pipe line, a small water pipe line, a telephone line, and the new State highway from Los Angeles to Bakersfield. In making the estimates, the costs of relocating all of these improvements, except the 126 DIVISION OF WATER RESOURCES highway, so tliat the}' would not be interfered witli by the water in the reservoir, have been included. It is estimated that for the construction of the dam the removal of residual shale over the left abutment to a depth of 6 feet normal to surface and the removal of 15 feet of loose material in the stream bed would be required to reach a firm shale foundation. Additional exca- vation into this firm shale for buttress footings and a cut-off wall at the upstream toe would also be required. The rock beneath the cut-off wall would have to be sealed by pressure grouting. In estimating the cost of the concrete it has been assumed that there is sufficient aggre- gate within the reservoir site and that the cement would be hauled by truck from the railroad at Castaic. The estimated total costs for the reservoirs with all heights of dam studied are given in the following table. TABLE 24 COSTS OF LOS ALAMOS RESERVOIRS WITH SLAB AND BUTTRESS DAMS Crest elevation, in feet, U. S. G. S. datum Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 2,374 2,387.5 ' 2,400 2,430 2,470 2,354 2,367.5 2,380 2,410 2,450 5,000 7,560 10,400 19,400 35,500 $952,600 1,224,600 1,549,000 2,448,800 4,309,500 $191 162 149 126 121 ' A detailed cost estimate of this reservoir is given on page 227. The items and unit prices shown in this estimate are the same as for other capacities. Liebre Creek Diversion to Los Alamos Reservoir. — Water from Liebre Creek, which enters Piru Creek below Los Alamos dam site, may be diverted over a low divide into the reservoir site. The dis- charge would be diverted from both the main channel and its West Pork by low dams and carried in concrete lined canals and flumes along the stream canyons to approximately opposite the point where the State highway crosses the divide between the Liebre and Los Alamos Creek w^atersheds. It would then be carried across Liebre Creek in a flume and through a culvert under the highway ; thence through the crest of the divide to a spillway into the reservoir. The West Pork canal would have a capacity of 40 second-feet and the Liebre Creek canal a capacity of 60 second-feet. The total cost of this diversion is pistimated at $51,960 and the detail is given on page 228. Spring Creek Reservoir Spring Creek Reservoir site is located on Piru Creek in Sees. 1, 2, 11, 12, 13 and 14, T. 6 N., R. 18 W., S. B. B. and M., in Los Angeles County. The dam site is located in the SE^- or Sec. 14. A topographic survey of the reservoir site was made by the Pair- child Aerial Surveys Incorporated for the Santa Clara Water Con- servation District and a map was drawn from this survey at a scale of one inch equals 400 feet, with a contour interval of 20 feet. The water surface areas measured from this map and the capacities of the reservoir computed from them are shown in the following table : VENTURA COUNTY INVESTIGATION 127 TABLE 25 AREAS AND CAPACITIES OF SPRING CREEK RESERVOIR Elevation of water surface, Area of water surface. Capacity of reservoir. in feet, L'. S. G. S. datum in acres in acre-feet 2,000 2.020 6 60 2,040 48 600 2.060 77 1,830 2,080 109 3,710 2.100 150 (j,700 2.120 202 10,220 2,140 250 14,740 2,160 296 20,200 2.180 340 26 560 2.200 386 33,820 2.220 431 41,990 2.240 476 51,060 2,260 521 61,030 2.280 566 71,900 2,300 611 83,670 The survey of the dam site was made by the State in March, 1933. A topographic map drawn from this survej^ at a scale of one inch equals oO feet, with a contour interval of 5 feet, was used in laying out and estimating the costs of dams of several heights and types. The geology of the reservoir and dam sites has been studied by Dr. Charles P. Berkey and Paul F. Kerr, Hyde Forbes, and Chester ]\Iarliave. The exploratory work that has been done at the dam site is drilling five holes across the stream bed to determine the depth of gravels and character of bedrock. Where these holes penetrated bed- rock diamond drills were used and the rock was cored. The following data on the geology of the site are from the report by Chester Marliave : For many miles upstream from the Spring Creek site the course of Piru Creek cuts through a thick series of clay shale beds, which have a general east and west trend, and in the vicinity of the reservoir site dip toward the north at about 40 degrees from the horizontal. The reservoir lies for the most part within these clay shales. Near the lower end of the reservoir the stream enters a constric- tion in the mountains which is composed of conglomerate interbedded with some sandstone layers. After passing through this formation for a distance of 1000 feet, the rocks change to granites which continue for several miles downstream from the dam site. The shales and conglomerates are sedimentary deposits, while the granite is an igneous intrusion of great depth. The shales are younger than the conglomerates and seem to rest unconformably upon them although there is evidence of faulting or folding along their contact in the reservoir site. There is a fault between the conglomerates and the granite and the granite is badly crushed and altered for several hundred feet downstream from the contact. The fault is a continuous one and is recorded on the Fault Map of California which was published by the Seismological Society of Amer- ica. Little is known concerning the activity of this fault, but it is considered inactive. The San Andreas Fault, hoAvever, which is known to be active, runs parallel with it about eight miles to the east. The reservoir site lies almost entirely within the clay shales which rest unconformably against the thick beds of compact conglomerate. 128 DIVISION OF WATER RESOURCES Tlit're woukl \)c no loss oi" stored water throii<2:li tlie bottom or sides of the reservoir, as it is lined with impervious formations. The bedrock formations in the vicinity of the dam site, as pre- viously noted, consist of clay shales, conglomerates, and granite. The foundation rock which occurs at the dam site selected, consists almost entirely of conglomerate and associated pebbly sandstone. The other formations, however, will be brieflj^ described. The clay shales of the reservoir are rather thin bedded and readily break down, yielding a thick clay soil. They are an unbroken forma- tion and can be followed up the canyon for several miles in a uniformly inclined attitude. There are several horizons included within the beds where sandstones predominate but they represent a small proportion of the series. The granite which is found downstream from the canyon constric- tion is badly altered and decomposed. It appears to be crushed along the fault contact and for several hundred feet more downstream. The granite was followed down the canj-on for about 3^ miles before rock was encountered which might be utilized in a rock fill dam. Xone was encountered that could be crushed for concrete aggregate. The conglomerate which forms the foundation rock at the proposed dam site is exceptionally hard and well cemented. It is composed of both angular and waterworn pebbles of granite, gneiss, quartz, and feldspar firmly cemented together. Some of the coarse granitic cobbles in it are minutely fractured, but where encased in the siliceous matrix do not materially weaken the strength of the rock mass. Like all sediments the rock has bedding planes, and in this case the dip is about 50 degrees to the north, while the bedding planes have a general north- east strike crossing the channel diagonally. From the logs of the drill holes, it is estimated that the maximum depth of gravels is about 60 feet below present stream bed and that the thread of the bedrock channel lies somewhat to the north of the surface channel, under the bench of gravel and talus that now rests against the right-hand side of the canyon. The cross-fracturing in the conglomerate is one of the poor qual- ities of the formation. Where the rock is massive it is generally fresii and void of fracturing and even the bedding planes are sometimes hard to distinguish ; but where the cross-fracturing exists, with planes of fracture traversing the rock and intersecting the bedding stratifica- tion, the elements have access to the rock mass, and it weathers and disintegrates. This is particularly true of certain ridges where the conglomerate has been attacked and has ravelled down onto the talus slopes leaving a residual mass of conglomerate pebbles. The conglomerate, where fresh, is insoluble and not subject to removal by solution. Crushed, fractured, and disintegrated conglom- erate may be attacked by water which would help to break down the cementing material of the matrix, but the firm compact rock would be free from this action. The conglomerate where intact is impermeable. The thick strata are massive and firmly cemented and exhibit no cavernous openings or porous unconsolidated len.ses. Certain bedding planes, however, appear to be open, but this is due to surface erosion along these seams which may be augmented b}' gravitational movement in conjunction with VENTURA COUNTY INVKSTIGATION 129 cross-becldiuji'. it is believed that the cross-l'i-aeturiiig' which is occa- sionally seen as thin fracture seams on the surface will tighten up or dis;ip])ear with increased depth. The right abutment of the dam is a high massive clitf extending several hundred feet above the top of the proposed dam. The rock is almost all fresh and free of open bedding planes. The structure has a uniform monoelinal dip and appears to be continuous across the canyon. Cross-fracturing is not prevalent on this side of the canyon. One small fault or slip has been noted, but this is only a tight fracture showing a 5-foot displacement. The left abutment of the dam is composed of the same conglomer- ate beds as are exposed on the right side of the canyon. There has been considerable erosion along some of the bedding planes on this side, and cross-fracturing seems to have assisted in the breaking up of the rock, especially along the higher elevations. Along the lower slopes of the canyon adjacent to the bottom, weathering has penetrated the bedding planes quite appreciably and a cut-oif would require removal of these outer layers in order to reach compact rock strata. This would be quite necessary in case of an arch dam in order to insure stability of the foundation to take thrust loading. At a point opposite the drill holes, on the left side of the canyon, at an elevation of 150 to 200 feet above the stream bed, there are sev- eral fracture planes, one of which at contour 2150 dips toward the creek at 45 degrees and another of which at contour 2100 dips into the hill at an average of 14 degrees. These fractures truncate the prominent ridge of rock on the left abutment and contain several inches of brecciated material along the fracture seams. The rock above these fractures on this ridge is unsatisfactory foundation rock for any type of dam and would have to be removed. A ridge 150 feet farther downstream on the same side of the canyon is likewise badly fractured and unstable, and the rock is of poor quality. The rock upstream from the first mentioned ridge is best suited for the abutment of a high dam. The channel section is covered with gravel and on the right side upstream from the drill holes there is considerable' talus which has ravelled down from the high cliffs above. The somewhat open and weathered bedding planes that stand out along the edge of the gravels on the left side of the canyon appear to be tight on the right w^all of the dam site so it is concluded that they become tight under the stream gravels. It is a fact that bedrock in the bottom of stream channels is generally fresh and free from open seams. Downstream from the drill holes there is a sheer bluff of conglomerate on the right hand side, but on the left side there is a talus slope at the foot of which is a)i accumu- lation of large detrital material. A concrete arch, gravity concrete, or rock fill dam could be con- structed at this site. Rock for the rock fill dam is available in the vicinity but aggregates for concrete dams and for the concrete facing on the rock fill dam would have to be hauled for a distance of about five miles. Geological conditions at the dam site give onl^'- limited space within which each of these types of dam could be constructed. Esti- 9 — 8367 — 8375 130 DIVISION OF WATER RESOURCES PLATE XXVII r VENTURA COUNTY IN VKSTIOATION I'U iiijitcs luivt' biH'ii made for all three lypes and llieso estimates, toj^'etlier with brief descriptions of the dams, are given herewith. Layout of a concrete arch dam 185 feet in heif>'ht is sliown on Plate XXVIII. Concrete Arch Dam — Estimates have been made of the costs of reservoirs with concrete arch dams 125, 185, 240 and 283 feet in height. All of these would be located in approximately the same position in the canyon. This position is governed by minor faults and fractures in the rock above and below the site. Each dam would be of the variable radius type and would be located to fit the solid rock best ada])ted for a foundation for its construction. For the two higher dams, a gravity concrete abutment would be constructed at the left end of the arch section. The two lower dams would be full arches between the solid rock of the canyon walls. For the two lower dams, the spill- way would be placed in the crest of the dam. This spillway would be 218 feet in length and its crest would be 20 feet below the top of the nonoverflow sections of the dam. With this length of spillway, a flow of 73,000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, would pass the dam without overto])ping the nonoverflow sections. No gates would be placed in the spillway and the normal maximum water surface would therefore be at the elevation of the spillway crest. The nonoverflow sections of the dam would have crest widths of 10 feet. For the two higher dams the spillway would be of the shaft and tunnel type with the inlet structure located on the right side of the creek on the northerly side of the first bend above the dam. The tunnel would extend through this bend to a point about 500 feet below^ the dam. The weir w^ould be circular in plan with a diameter of about 100 feet between the spillway crests. The shaft would taper from this diameter to 28.2 feet for the highest dam and 29.6 for the next to liighest dam. These latter diameters would be those of the outlet tunnels. The crest of the spillway would be 314 feet in length and at an elevation 17 feet below the crest of the arch dam. This spillway w^ould also pass 73,000 second-feet without the water overtopping the concrete arch dams. The outlets through the dams would consist of two 36-inch steel pipes embedded in the concrete. Flow through each outlet would be controlled by a needle valve at the downstream face of the dam. Each outlet would also be equipped with an emergency roller type gate at the inlet end. This gate would be operated from the top of the dam and protected by steel trash racks set in a closed concrete structure extending to the top of the dam. In making the estimates, it was assumed that 10 to 75 feet of rock would be removed from the abutments and 15 to 80 feet of talus, gravel and decomposed rock from the stream bed. The rock beneath the foun- dation of the dam would also be sealed by pressure grouting. In esti- mating the cost of the concrete, it has been assumed that the aggre- gates would be hauled from a pit five miles from the site and that the cement would be hauled by truck from the railroad at Castaic. The land in the reservoir site is all government owned and it has been assumed that there would be no cost for its acquisition. There is, how- ever, a steel tower transmission line crossing the site, the cost of the 132 DIVISION OF WATER RESOURCES relocation of which has been inehidcd in the estimates. The new State highway from Los Angeles to Bakersfield passes throngh a large portion of the site but the cost of its relocation has not been included in the estimates. The estimated total costs for the reservoirs with all heights of con- crete arch dams studied are given in the following table : TABLE 26 COSTS OF SPRING CREEK RESERVOIRS WITH CONCRETE ARCH DAMS Crest elevation, in feet, U. S. G. S. datum Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 2,120 •2,180 2,235 =2,278 2,100 2,160 2,218 2,261 6,700 20,200 41,000 61,500 $1,069,800 1,954,600 4,350,500 5,464,900 $160 97 106 89 'A detailed cost estimate of this reservoir is given on page 228. The same items and similar unit prices were used for the next lower dam. ^A detailed cost estimate of this reservoir is given on page 229. The same items and similar unit prices were used for the next lower dam. Gravity Concrete Dam — Estimates have been made of the costs of reservoirs with gravity concrete dams 145, 185, 214.5, 237 and 280 feet in height. All of these dams would be located with the down- stream toe in the same position. This position is governed by a minor fracture in the rock just below the foundation site. The location of the upstream face would vary wdth the height of dam. The dams would be of the gravity concrete type with vertical upstream face and down- stream slope of f :1 starting from the upstream crest line. The crest would be 20 feet in width and there would be an approximately vertical face from the downstream crest line to an intersection with the down- stream slope of the dam. For the three lower heights of dam, the spill- way would be placed in the crest of the dam. This spillway would be 218 feet in length and its crest would be 20 feet below the top of the nonoverflow sections of the dam. With this length of spillway, a flood of 73,000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, w^ould pass the dam without over- topping the nonoverflow sections. No gates would be placed in the spillway and the normal maximum water surface would therefore be at the elevation of the spillway crest. The spilhvays for the two highest dams would be of the shaft and tunnel type. They would be the same spillways which have pre- viously been described for the concrete arch dams of approximately the same heights. The outlets through the dam would consist of two 36-inch steel pipes embedded in the concrete. The gates, valves, trash racks and operating structures would be similar to those previously described for the concrete arch dams. In making the estimates it was assumed that the necessary excava- tion on the abutments would vary from 10 to 25 feet normal to the surface and that 15 to 90 feet of talus, gravel, and decomposed rock would be removed from the stream bed. The rock beneath the foun- dation of the dam would also be sealed by pressure grouting. In VENTURA COUNTY INVESTIGATION 133 estimatiug the cost of the concrete, it has been assumed that tlie aggre- gates would be hauled from a pit five miles from the site and that the cement would be hauled by truck from the railroad at Castaic. The land in the reservoir site is all government owned and it has been assumed that there would be no cost for its acquisition. The cost has been included, hoAvever, for the relocation of a steel tower transmission line crossing the site. Xo cost has been included in the estimates for the relocation of the new State highway from Los Angeles to Bakers- field which passes through a large portion of the site. The estimated total costs for the reservoirs with all heights of gravitv concrete dams studied are given in the following table : TABLE 27 COSTS OF SPRING CREEK RESERVOIRS WITH GRAVITY CONCRETE DAMS Crest elevation, in feet, U. S. G. S. datum Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 2,140 >2.180 2,209 5 2,232 =2,275 2,120 2,160 2,189 5 2.215 2,258 10,200 20,200 30,000 39,800 60,100 $1,464,200 2,212,600 3,118,100 4,367,300 5,952,800 $143 110 104 110 99 ' .\ detailed cost estimate of this reservoir is given on page 230. used for the next lower dam. = A detailed cost estimate of this reservoir is given on pa^e 231. used for the next two lower dams. The same items and similar imit prices were The same items and similar unit pricjs were Rock Fill Dam — Estimates have been made of the costs of reser- voirs with rock fill dams 147, 187, 242, 285 feet in height. All of these dams were located with the center line of the crest in the same position in the canyon. The dam would have a crest width of 15 feet, an upstream slope of 1.3:1, and a downstream slope of 1.4:1. The entire section would be built with rock dumped in place, with the exception of a layer 15 feet in thickness over the entire upstream face which would be constructed of large derrick placed rocks. The upstream face of the dam would be covered with a concrete facing and a heavy concrete cut-off wall along the toe of the dam, extending into bedrock would be constructed. Below this cut-off wall, the founda- tion rock would be sealed by pressure grouting. The concrete facing would consist of a subslab 12 inches in thickness at the top increasing one inch in thickness in each 25-foot depth of dam. Over this sub- slal) there would be a laminated reinforced concrete facing composed of slabs six inches in thickness. There would be two of these slabs for the first 75-foot depth of dam, and one more slab would be added in each additional 75 feet of depth. The spillway for all heights of dam Avould be of the side channel type located on the left side of the canyon with the crest immediately upstream from the crest of the dam. The spillway crest would be ■305 feet in length and 22 feet below the crest of the dam. With this length of crest, a flood of 73,000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, would pa.ss the dam without encroaching on the upper 7 feet of freeboard. Xo gates would be placed in the spillway and the normal maximum water surface would therefore be at the elevation of the spillway crest. 134 DIVISION OP WATER RESOURCES The spillway channel would have bottom widtlis increasing from 60 feet at the u])stream end to about 100 feet opposite the crest of the dam and would continue with this bottom wi(,lth through the ridge at the left abutment of the dam. The water on leaving the spillway channel would flow down the rock surface of the ridge and into the creek channel several hundred feet below the dam. The spillway crest and channel would be lined with reinforced concrete. The creek would be diverted during construction througli a concrete lined tunnel 20 feet in diameter under the left abutment of the dam. After the completion of the dam, tliis 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 60-inch steel pipe laid througli this plug and extended through the tunnel to its downstream end. A slide gate would be placed in the pipe just downstream from the tunnel plug and a needle valve for regulating the flow would be placed at the outlet end. A trash rack structure would be constructed at the inlet of the tunnel. In making the estimates, it was assumed that talus and gravel to depths of from 15 to 90 feet would be removed from the stream bed over the entire foundation for the dam and that loose and decomposed rock to depths of from 5 to 60 feet would be removed from the abut- ments. In estimating the cost of the concrete, it has been assumed that the aggregates would be hauled from a pit five miles from the site and that the cement would be hauled by truck from the railroad at Castaic. The land in the reservoir site is all goverment owned and it has been assumed that there would be no cost for its acquisition. The cost has been included, however, for the relocation of a steel tower transmission line crossing the site. No cost has been included in the estimates for the relocation of the new State highway from Los Angeles to Bakers- field which passes through a large portion of the site. The estimated total costs for the reservoirs with all heights of rock fill dams studied are given in the following table : TABLE 28 COSTS OF SPRING CREEK RESERVOIRS WITH ROCK FILL DAMS Crest elevation, in feet, U. S. G. S. datum Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 2,142 '2,182 2,237 2,280 2,120 2,160 2,215 2,258 10,200 20,200 39,800 60,100 $2,652,000 3,578,000 4,897,000 6,442,000 $260 177 123 107 'A detailed cost estimate of this reservoir is given on page 232. The same items and similar unit prices were \ for the other dams in the table. Blue Point Reservoir. The Blue Point Reservoir site is located on Piru Creek in Sees. 3, 4, 9 and 10, T. 5 N., R. 18 W., S. B. B. and M. in Ventura and Los Angeles counties. The dam site for the reservoir is located about 500 feet north of the south line of Sec. 10. VENTURA COUNTY INVKSTIGATION 135 A topographic survey of the r'cservoir site was made by the State ill April, 1981. and a map was drawn from this survey at a scale of one inch equals 400 feet, with a contour interval of 20 feet. The water surface areas measured from this map and the capacities of the reservoir computed from them are shown .in the following- table: TABLE 29 AREAS AND CAPACITIES OF BLUE POINT RESERVOIR Elevation of water surface, Area of water surface. Capacity of reservoir, in feet' in acres in acre-feet 1,110 1,120 2 10 1,140 28 318 1,160 65 1,254 1,180 127 3,173 1,200 180 6,244 1,220 232 10,368 1,240 279 15,476 1,260 326 21,528 1,280 377 28,562 1,300 444 36,768 • Subtract 45 feet to obtain U. S. G. S. elevation. The survey of the dam site was made by the State in March, 1931, and additional" data were obtained in IMarch, 1933. A topographic map drawn from this survey on a scale of one inch equals 200 feet with a contour interval of 10 feet was used in laying out and estimating the costs of dams at the Blue Point site. The geology of the region and the dam site has been studied by Dr. Charles P. Berkey and Paul F. Kerr, Hyde Forbes, and Chester Marliave. The dam site has been explored by trenching on both abut- ments and by test hole drilling. Five holes were drilled in the stream bed and four of these penetrated the stream gravels and were con- tinued into the bedrock. One hole was bored vertically into the right abutment at an elevation about 160 feet above the stream bed. The following geological data have been taken from a report by Chester Marliave : The region in the vicinity of the dam site is composed entirely of Tertiaiy 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 syn- clines which are conspicuous 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. In the vicinity of the dam site the sedimentary beds are in the reverse order from the way that they were laid down. The older or earlier formations now rest upon the younger or later ones. This condition is due to an overturned anticline located about a mile upstream from the site which is one of the main structural features of the folding in this vicinity. 136 DIVISION OF WATER RESOURCES Tile bedrock at the 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 resistant 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 underlying these harder strata weather easily so that there are high vertical bluffs on their downstream side. Resting upon these hard thin sandstone 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 50 degrees from the horizontal, while the strike is at right angles to the direction of the stream channel. The channel section at the dam site is about 175 feet wide at the constriction of the 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. This information is on record in previous geologic reports. The mate- rial 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. This is obscured by the stream gravels, but there is evidence of its existence. The straight uniform channel of the stream for a distance of 6000 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. At the dam site the beds along the contact of the Sespe and Vaqueros formations do not closely line up across the stream bed. They appear to merge beneath the gravels with a horizontal displacement of about 25 feet, the strata on the left abutment having moved upstream with reference to the strata on the right abutment. The apparent displacement of about 25 feet might result from a bending or folding of the strata beneath the channel, but the dislocation is nevertheless evident. There is step faultino: along the white strata in the bluff near the stream bed. Tliis shoAvs movement in the direction mentioned. If this step faulting continues below the stream bed to accumulate the displacement of 25 feet, then the bedrock is A^ery badly fractured, but if it does not continue then there is probably quite a slip causing the displacement, and the stream has cut its channel along this line or zone of weakness. 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 uniformly upstream in a monoclinal structure across tlie site. There is a large amount of talus material scattered along the bottom of the draw over wdiich 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. VENTURA COUNTY INVESTIGATION 137 The riojht end of the dam sljould rest in the depression upstream from the prominent outerojiped rib of rock on tliat side of the canyon. Within the immediate limits of tlie dam site, the structure at this abutment is monoclinal but the upper portion merges into an inclined syncline which is badly distorted and faulted. One fault traverses the abutment in a vertical direction at an elevation of about 140 feet above the stream bed and has probably crushed the bed rock 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. It is believed that on account of foundation conditions, only a flexible type of dam Avith 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 till is found just below the dam site. The earth fill type was therefore selected as the most suitable for this reservoir. Also, on account of foundation conditions, it is doubtful that a dam more than 150 to 175 feet in height would be safe. Estimates have therefore been made for the costs of reservoirs with earth fill dams 130 and 165 feet in height. Layout of a dam 165 feet in height is shown on Plate XXIX. Both of these dams would be located with the crest line or axis well into tlie depressions just upstream from the prominent outcropping ribs or bluffs at the site, described above. The dam would have a crest width of 20 feet, an upstream slope of 2.5 :1, and a downstream .slope of 3 :1. It would be of the rolled fill type. All of the downstream section lying between the downstream face of the dam and a plane on a slope of 1 :1 from the downstream crest line would be of pervious material obtained from the stream channel. Under this section of the dam, no material would be excavated except for the removal of loose surface material and vegetation. The remainder of the dam would be constructed of impervious material obtained from borrow pits in the vicinity of the dam and could be compacted by rolling. Under this section of the dam all loose material would be excavated to a firm rock foundation. The U])stream face of the dam would be protected by a 6-inch layer of reinforced concrete terminating in a small toe wall set into the solid rock at the toe of the dam. The spillway would be of the side channel type and would be located on the right side of the canyon with the crest just upstream from the crest of the dam. The spillway crest would be 311 feet in length and 25 feet below the top of the dam. With this length of spill- way it is estimated that a flood of 98.000 second-feet, the estimated crest flow of a flood Avhich may occur once in 1000 years on the average, will pass the dam without encroaching on the upper seven feet of the freeboard. No gates would be placed in the spillway and the normal maximum water surface would therefore be at the elevation of the spillway crest. The spillway channel would have bottom Avidths increas- ing from 30 feet at the upstream end to 109 feet opposite the down- stream end of the spillway crest. It would then decrease in width as the channel follows down the slope of the canyon wall to the stream bed. The spillway crest and the channel would be lined with reinforced concrete. 138 DIVISION OF WATER RESOURCES PLATE XXIX < UJ I— Ld n Z en °- n ° OQ v \ N ^.^ o E k ^ V / • |3uuE^j3 (ei.wds ^ 25 §■= IJO OS o o o o o o o o o o o o ;33J Ul UOI4BA3I3 VEXTURA COUXTY TXVESTIGATIOX 139 Tlie stream would be diverteil diiriiiji' cDnstruction throuj;!! a con- crete lined tunnel 20 feet in diameter under the rio^ht abutment of the dam. After the comph»tion of the dam, this tunnel would be used for the outlet from the reservoir. A concrete jilug would be placed in the ui^stream end of the tunnel and a 6()-inch steel pipe would be laid through this plug and extended through the tunnel to its downstream end. A slide gate would be placed in the pipe just downstream from the plug and a needle valve for regulating the flow would be placed at the outlet end. A trash rack structure would be constructed at the inlet of the tunnel. Only a portion of the land in the reservoir is i)rivately owned and the remainder belongs to the United State Government. It is therefore assumed that the only cost for the reservoir site would be for the acqui- sition of about 320 acres of the privately owned lands with the improve- ments. There are no other improvements within the reservoir site which would have to be acquired or relocated. It is estimated from borings and surface indications that 15 to 90 feet of gravel and boulders would be removed from the stream bed under the impervious section of the dam and that 5 to 30 feet of soil and decomposed rock would be removed from the abutments under the same section. The material for the impervious section could be obtained from borrow pits located on both sides of the canyon about 1.500 feet below the dam site. Gravel and sand for the concrete could be obtained from the stream bed for a distance of about one mile downstream from the dam site. The cement would be hauled by truck from the railroad at Piru. The estimated total costs for the reservoirs with both heights of earth fill dams studied are given in the following table : TABLE 30 COSTS OF BLUE POINT RESERVOIRS WITH EARTH FILL DAMS Crest elevation, in feet> Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 1,245 '1,280 1,220 1,255 10,500 20,000 $3,033,800 3,514,000 1289 176 ' Subtract 45 feet to obtain U. S. G. S. elevation. 'A detailed cost estimate of this reservoir is given on page 233. The same items and similar unit prices were used for the lower dam. Devil Canyon Reservoir. Devil Canvon Reservoir site is located on Piru Creek in Sees. 3, 4, 9, 10, 14, 15, 16, 21, and 22, T. 5 N., R. 18 W., S. B. B. and M. The dam site for the reservoir is located in the south half of Sec. 22 about 300 feet north of the south line of the section. A topographic survey of the reservoir site was made by the State in April, 1931, and a map was drawn from this survey at a scale of one inch equals 400 feet, with a contour interval of 20 feet. The water surface areas measured from this map and the capacities of the reser- voir computed from them are shown in the following table : 140 DIVISION OF WATER RESOURCES TABLE 31 AREAS AND CAPACITIES OF DEVIL CANYON RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir. in feet> in acres in acre-feet 1,030 2 1,040 25 135 1,060 57 955 1,080 93 2,455 1,100 173 5,115 1,120 263 9,475 1,140 347 15,575 1,160 424 23,285 1,180 531 32,835 1,200 628 44,425 1,220 726 57,965 1,240 823 73,455 ' Subtract 45 feet to obtain L'. S. G. S. elevation. A survey of the dam site was made by the State in April, 1933. A topographic map dra-oii from this survey on a scale of one inch equals 100 feet with a contour interval of 10 feet was used in laying out and estimating the costs of the dams at the DcA'il Canyon site. The geology of the region and the dam site has been studied by Dr. Charles P. Berkey, Paul F. Kerr, Hyde Forbes and Chester Mar- liave. The exploration work that has been done at the dam site is sinking two test pits, drilling two test holes at the base of slope and one 150 feet up the slope on the right side of the canyon to determine the character of the foundation rock, and drilling two holes in the stream bed to determine the depth of the gravel fill and the character of the underlying rock. The following geological data have been taken from a report by Chester ^Nlarliave : The region is one of Tertiary sediments composed for the most part of clay shales and interbedded sandstones with occasional strata of conglomerate. The area has been subjected to lateral compression in a general north and south direction with the resulting anticlinal and synclinal folds having an east and west trend. ]\linor faulting has accompanied some of the folding, but no breaks or dislocations jiave been observed passing through the dam site. Tlie reservoir site above the proposed Devil Canyon Dam rests entirely upon the sediments of the ]\rodelo formation. This series of Tertiary sediments is made up of beds of diatomaceous and clay shales interbedded with sandstone and some conglomerate. The series would form a tight and impervious reservoir. The bedrock at the dam site is also part of the Modelo series. Sand- stone and shales form the two abutments and appear to be continuous under the stream gravels. Some of the strata can be projected across the canyon and identified on the opposite slopes, which indicates that there is evidently no major faulting down the canyon. The sandstones are more resistant to weathering than are the shales and stand out more prominently on the hillsides. They are mostly coar.se grained and white to buff colored on the surface, and are occasionally massive but generally alternately bedded with the shales in varying ]n-oportions. Some of the sandstone strata are quite liard and ring under the hammer, but these strata are seldom over 5 feet in VENTURA COUNTY INVESTIGATION 141 tliu'kness. I'lu'v are coiitimious, liowever, across the caiiyou and if Tliey are unbroken in the stream Ix'd wonhl act as cut-offs to any l)ercohitin^' ground water. The sandstone, for the most part, is poorly cemented and some of the beds weather rather unevenly. The shales at the dam site are mostly siliceous, with some dark colored clay partings interbedded. They Aveather down into small flat angular fragments along the outcrops yielding a soil which feels much like a handful of soda cracker crumbs. The structure of the beds at the dam site selected is monoclinal but liaving a slight curve. It forms the south limb of an anticlinal fold that, turns over just a short distance above the upstream toe of the dam site. The beds at the dam site, however, appear to be continuous from one side of the canyon to the other, dipping do\\^istream at an average angle of 45 degrees from the horizontal. The direction of the bedding x^lanes strikes across the canyon almost at right angles to the canyon. The solubility of the foundation rock is not appreciable. There is verj' little evidence of solution leaching out the cementing material either in the sandstones or the shales, nor is there any structure in the bedrock that might be weakened by such action. The permeability of the rock is not very great. The attitude of the beds dipping downstream would tend to seal off any water from getting through the abutments as each stratum would act as a cut-off to stop it. The total distance of travel to get around the dam would be so great that could any seepage percolate through the formation, which is unlikely, the rate of flow would be very small. The steep attitude of the beds would force any contained water down along these planes into the bedrock where it would seal itself oif from escape. On the right abutment of the dam site, the strata are not as well exposed as on the opposite side of the canyon. However, the bedrock has been exposed nearly continuously along the bottom of the abut- ment at its junction with the gravel fill. The rock formation thus exposed is much the same and .shows a cross section of the various beds that make up the foundation rock over the whole abutment which is continuous with that under the channel and on the opposite abutment. There is one ravine that has been eroded down the face of this abut- ment, but examination shows that it is only an erosional feature and discloses no structural break. On the downstream side of the ridge forming the right abutment there is a fault contact. This is an inactive fault, sui^iciently far removed from the end of the proposed dam not to affect the integrity of the abutment. On the left abutment of the dam site, the strata are inclined, with the more resistant sandstone ridges standing out in relief. The strata are not distorted and have a uniform structure. The anticlinal axis of folding runs up a canyon which is just upstream from the toe of the proposed dam. This canyon, which in general indicates the axis of flexure, was examined and shows no faulting, for the beds can be fol- lowed continuously across the canyon and dow^^ over the abutment of the dam. This character of the strata wdiich has permitted them to bend without fracturing and faulting shows them to be favorable as 142 DIVISION OF WATER RESOURCES PIRATE XXX 1 '^ < u U 0- Z o - O < 3 IL ^-^ Q. > UJ Q \ K I f1 - 1 1 -1 — k Ids r 23 if u C ll. = 433J UI uo!;eA3|3 VENTURA COUNTY INVKSTKiATION 14.") Jouiulatioii rock lor a (Uiiii. 'I'lie even surfaced slopes along the upstream toe of the dam indicate that the shale and sandstone have weathered evenly, leavin<^- no ])rominent outcropi)infi' of hard sandstone. The channel section is about 400 feet wide and contains a gravel fill with a maximum dei)th of 80 to 90 feet. There is nothing in the i-egional geology to suggest faulting down the canyon and the structural conditions on both sides of the canyon indicate a continuity of the for- mations across the bottom. It is believed that on account of the character of the foundation materials, only a broad based, flexible type dam should be constructed at this site. No rock for a rock fill dam is available within reasonable hauling distance, so all estimates made for dams at this site are based on an earth fill type. Estimates have been made for the cost of reservoirs with dams 110, 146, 185 and 215 feet in height. Layout of a 185-foot dam is shown on Plate XXX. All of these dams were located with the crest or axis line in the same position in the canyon. This position is about half way between the ravines in the right and left abutments referred to above, and 300 feet north of the south line of Sec. 22. The dam would have a crest width of 20 feet, an upstream slope of 2.5:1 and a downstream slope of 3:1. All of the downstream section lying between the downstream face and a plane on a slope of 1:1 from the downstream crest line would be of ])ervious material obtained from the stream channel and rolled into place. Under this section of the dam, no material would be excavated except for the removal of loose surface material and vegetation. The remainder of the dam would be constructed of impervious material obtained from borrow pits in the vicinity of the dam and compacted either by the hydraulic process or by rolling. Under this section of the dam all loose material would be excavated to a firm rock foundation. The upstream face of the dam would be protected by a 6-inch layer of reinforced concrete terminating in a small toe wall set into the solid rock at the toe of the dam. The spillway would be of the side channel type and would be located on the right side of the canyon with the crest just upstream from the crest of the dam. The spillway crest would be 314 feet in length and 25 feet below the to]) of the dam. With this length of spill- way it is estimated that a flood of 106,000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, will pass the dam without encroaching on the upper 6.5 feet of the freeboard of the dam. No gates would be placed in the spillway and the normal maximum water surface would therefore be at the elevation of the sjullway crest. The bottx)m of the spillway channel would vary in width from 15 feet at the ui)i)er end to 125 feet oii])Osite the down- stream end of the spillway crest. It would then decrease in width as tlie channel follows down the slope of the canyon wall to the stream bed. The spillway crest and the channel would be lined with reinforced concrete. The stream would be diverted during construction through a con- crete lined tunnel 20 feet in diameter under the right abutment of the dam. After the completion of the dam, this tunnel would be used for llie outlet from the reservoir. A concrete plug would be placed in the upstream end of the tunnel and a 60-inch steel pipe would be laid 144 DIVISION OF WATER RESOURCES through this plug and extended through the tunnel to its down.stream end. A .slide gate Mould be placed in tliis pipe just downstream from the plug and a needle valve for regulating the flow would be placed at the outlet end. A trash rack structure would be constructed at the inlet of the tunnel. Only a portion of the land in the reservoir is privately owned and the remainder belongs to the United States Government. It is there- fore assumed that the only cost for reservoir lands would be for the acquisition of about 650 acres of the privately owned lands. The only improvements within the reservoir are those on the lands which M'ould be acquired and they would not have to be relocated. It is estimated from the borings and from surface indications that 10 to 90 feet of gravel and boulders would be removed fi-om tlie stream bed under the impervious section of the dam and that 5 to 20 feet of soil and decomposed rock would be removed from the abutments under the same section. The material for the impervious section could be obtained from borrow pits located on the left side of the canyon about 1500 to 2000 feet downstream from the center line of the dam. Gravel and sand for concrete could be obtained from the stream bed a short distance below the dam site. The cement would be hauled by truck from the railroad at Piru. The estimated total costs for the reservoirs with all heights of earth fill dams studied are given in the following table: TABLE 32 COSTS OF DEVIL CANYON RESERVOIRS WITH EARTH FILL DAMS Crest elevation, in feet> Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 1,145 1,181 =1,220 1,250 1,120 1,156 1,195 1,225 9,400 21,500 41,300 61,500 12,705,800 3,321,800 3.991,100 4,738,700 {288 155 97 77 ' Subtract 45 feet to obtain U. S. G. S. elevation. ■A detailed cost estimate of this reservoir is given on page 234. The same items and similar unit prices were used for the other dams. Cold Spring Reservoir Cold Spring Eeservoir site is located on Sespe Creek in Sec. 6, T. 5 N., R. 22 W., S. B. B. and M. ; Sees. 1, 2 and 3, T. 5 N., B. 23 W., S. B. B. and M. ; and Sees. 31 and 32 in T. 6 N., E. 22 W., S. B. B. and I\I., in Ventura Countv. The dam site for the reservoir is located in lots 8 and 9 of Sec. 6, T. 5 N., R. 22 W., S. B. B. and ]\I., about one- half mile upstream from the month of Howard Creek. A topographic survey of the reservoir site was made by the engineering offices of J. B. Lippincott in July, 1925, and a map was drawn from this survey at a scale of about one inch equals 600 feet with a contour interval of 10 feet. The water surface areas measured from this map and the capacities of the reservoir computed from them are shown in the following table : VENTURA COUNTY INVESTIGATION 145 TABLE ii AREAS AND CAPACITIES OF COLD SPRING RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir. in feet in acres in acre-feet 3,210 3,220 2 10 3,230 10 70 3,240 22 230 3,250 35 515 3,260 55 965 3,270 70 1,590 3,280 95 2,415 3,290 125 3,515 3,300 158 4,930 3,310 196 6,700 3,320 226 8,810 3,330 256 11,220 3,340 292 13,960 3,350 350 17,170 3,360 412 20,980 3,370 480 25,440 3,380 550 30,590 3,390 620 36,440 3,400 690 42,990 3,410 762 50,250 3,420 843 58,275 A survey of the clam site was also made by the engineering- offices of J. B. Lijipincott. A toi)()0'raphie map drawn from this survey at a scale of one inch ec^uals 100 feet, with a contour interval of 10 feet, was used in laying- out and estimating the costs of dams at the Cold Spring site. The geology of the dam site has been studied by Dr. Charles P. Berkey and Paul F. Kerr, and Hyde Forbes. No exploratory work of any kind has been done at the dam site. The following geological data on the dam site have l)een taken from the report by Dr. Berkey and Paul F. Kerr: The proposed site is located in an area of moderately' inclined sandy shales and sandstone of Eocene age. The strata lie nearly flat at the best location, being only slightly arched so that the angle of dip is not more than 8 degrees from the horizontal. Several resistant sandstone beds are exposed on the canyon walls oil either side of the proposed dam site. One of these beds outcrops along the north canyon wall and continues for several hundred yards on either side of the proposed dam site. It is a bed of approximately 25 feet in thickness, and is made up of hard, massive sandstone. The bed is almost flat-lying, but at a point upstream from the dam site a dip of approximately 8 degrees was observed. Lower on the north hillside are other sandstone members, some of which are decidedly lenticular, and can not be traced for any great distance on either side of the dam site. Between the sandstone members are considerable thicknesses of sandy shale agreeing in attitude with the strike and dip of the sandstone members. The conditions in the south wall of the canyon are similar in many respects to those just described for the north wall. Prominent sand-, stone beds are also exposed with intervening shale. The beds on the south side of the canyon, however, do not appear to match the beds 10— S3G7 — 837-5 146 DIVISION OF WATER RESOURCES PLATE XXXI s < a ^ III o UJ z IT ( ) CO UJ OL to Ul o to _l O o *l ^ \ / 1 — 5 :^ 130 :f i DC o 488J Ul UO!iEA3|3 VENTURA COUNTY INVESTIGATION 147 ill till' iitiitii canyon wall. This situation seems to lie (liic to tlu* len- ticular habit of the individual beds of this formation. It is probable that the ])eds on the north side g^radually thin down and virtually disappear before reaehiiifi: the south canyon wall. Similarly, some of the beds of the south canyon wall seem to disappear before reaching: the opposite side of the canyon. The result of this lenticularity is an ajiparent discrepancy in the strata of the two sides of the canyon. This normally suo-orests displacement. Continuation of some of the beds around the bend below the dam site, however, shows that the discrepancy is entirely due to original sedimentation instead of to faulting-. On account of the location of the site, the character of the founda- tion rock, and the materials for dam construction available in the vicinity, the only type of dam for which estimates were made is the earth fill. Estimates have been made of the costs of reservoirs with dams 145, 175 and 215 feet in height. Layout of a 215-foot dam is shown on Plate XXXI. All of these dams would be located in approxi- mately the same position in the canyon, which is just above a 90-degree bend in the stream and just west of the east line of Sec. 6. Each dam would be located so that the downstream toe would lie just above the bend in the stream. The dam would have a crest width of 20 feet, an u])stream slope of 2.5:1, and a downstream slope of .3:1. The central portion of the dam lying between planes on slopes of 1.5 :1 upstream and downstream from the upstream and downstream crest lines, respec- tively, would be placed wet by the hydraulic process. The remainder of the material in the dam would be placed dry and compacted by rolling. A cut-oflP trench about 30 feet deep and 30 feet in width would be excavated on approximately the center line of the dam, across the entire canyon, and back-filled with wet material during the con- struction of the dam. All gravel and loose material in the stream bed and loose and decomposed material on the two abutments would be removed under the upstream rolled section and the central section of the dam placed by the hydraulic method. The upstream face of the dam would be protected by a six-inch layer of reinforced concrete terminating in a small toe wall set into the solid rock at the toe of the dam. The spillway would be an open cut channel through the ridge which forms the left abutment of the dam. The weir at the inlet to this channel would be at right angles to the center line of the channel and would be 100 feet in length. The crest of the weir would be 25 feet below the top of the dam. This .spillway channel would have a capacity of 23,500 second-feet, the crest flow of a flood which may occur once in 1000 years on the average, with a net freeboard of over 6 feet on the dam. The channel would narrow from a 100-foot bottom width at the weir to 60 feet at a distance of about 50 feet from the weir and would continue with this width through the ridge. The water would then spill down the side of the canyon into the creek bed some distance below the dam. The spillway weir and the channel would be lined with reinforced concrete. The stream would be diverted during constriu-tion through a con- crete lined tunnel 12 feet in diameter under the left abutment of the dam. The inlet and outlet to this tunnel would be in concrete lined 148 DIVISION OF WATER RESOURCES open cuts. After the completion of the dam, this tunnel would be used for the outlet from the resei-voir. A concrete plug would be placed in the upstream end of the tunnel and a 60-inch steel pipe would be laid through this plug and extended through the tunnel to its downstream end. A slide gate would be placed in this pipe just below the plug and a needle valve, for regulating the flow, would be placed at the outlet end. A trash rack structure would be constructed at the inlet of the tunnel. Most of the land in the reservoir site is owned by the United States Government and it is assumed that there would be no cost for the acquisition of these lands. There are, however, four privately owned parcels aggregating about 360 acres which would have to be purchased. The only improvements within the reservoir are a few buildings on these privately owned lands and these would be acquired Avith the land. It has been estimated that 10 to 80 feet of gravel and earth would have to be removed from the stream bed and about 10 feet of soil and decomposed rock from the abutments, to obtain a solid rock foundation. The materials for both the pervious and impervious sections of the dam could be obtained from borrow pits in the reservoir site a short distance from the dam. Concrete aggregates would probably have to be obtained in the vicinity of Santa Paula and hauled to the site by trucks. Cement would be hauled from the railroad at Ojai. The estimated total costs for the reservoirs with all heights of dams studied are given in the following table : TABLE 34 COSTS OF COLD SPRING RESERVOIRS WITH EARTH FILL DAMS Crest elevation, in feet Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 3.355 3,385 > 3,425 3,330 3,360 3,400 11,220 20,980 42,990 $1,503,000 1,642,400 1,979,200 $134 78 46 'A detailed cost estimate of this reservoir site is given on page 235. The same items and similar unit prices were used for the other dams. Topa Topa Reservoir Topa Topa Reservoir site is located on Sespe Creek in Sees. 26, 27, 32, 33, 34, 35 and 36, T. 6 N., R. 20 W., S. B. B. and M., in Ventura County. The dam site for the reservoir is located in the SW^ of Sec. 36. A topographic survey of the reservoir site was made by the Fair- child Aerial Survey, Incorporated, for the State in December, 1932. and a map was drawn from this survey at a scale of one inch equals 400 feet with a contour interval of 20 feet. The water surface areas measured from this map and the capacities of the reservoir computed from them are shown in Table 35. The survey of the dam site was made by the Santa Clara Conserva- tion District in May, 1932. A topographic map drawn from this survey on a scale of one inch equals 100 feet with a contour interval of 10 feet was used in laying out and estimating the costs of the dams at the Topa Topa site. VENTURA COUNTY INVESTIGATION 149 TABLE 35 AREAS AND CAPACITIES OF TOPA TOPA RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir, in feet' in acres in acre-feet 2.090 1 2,100 7 40 2,120 14 250 2,140 33 720 2,160 53 1,580 2,180 76 2,870 2,200 99 4,620 2,220 125 6,860 2,240 168 9,790 2,260 214 13,610 2,280 256 18,310 2,300 293 23,800 2,320 351 30,240 2,340 415 37,900 2,360 470 46,750 2,380 533 56,780 2,400 618 68,290 1 Add 56 feet to obtain U. S. G. S. elevation. The g-eology of the dam site has been studied by Dr. Charles P. Berkey and Paul F. Kerr, and Hyde Forbes. No exploratory work of any kind has been done at the dam site. The following geological data have been taken from the report by Dr. Berkey and Paul F. Kerr : The formations at the Topa Topa location are of Eocene age, and probably belong to what is known as the Matilija sandstone member of the Te.jon formation. The strata forming the floor and walls of the canyon at the dam site consist of beds of a hard, massive, greenish, mottled sandstone. The individual beds vary in thickness from a few inches to over 50 feet. Some are very uniform and massive and strongly resistant to erosion. The inclination of the strata is approxi- mately 12 degrees, and the dip, which is remarkably uniform in the immediate vicinity of the dam site, is downstream. Between the large massive sandstone beds there are occasional thin beds of sandy shale. These vary from 2 or 3 inches to a foot or more in thickness, and do not resist erosion as well as the associated massive sandstones. The sandstones are prominently jointed, and frost action has pried off many blocks, the detrital material going to make up talus accumulations that obstruct the gorge. The individual blocks vary from a few inches in thickness to some that are 20, 30, or even 50 feet across. Although there has been enougli deformation to develop a con- siderable amount of jointing, little displacement has been recorded. Occasional displacements of from 1 to 6 inches were observed. There is virtually no gouge clay in the seams or joints, and all could be tilled by grouting. The sandstones forming the foundation and the abutments are very substantial rocks. The beds are hard and resist weathering well, as is shown by the cross profile of the gorge. The walls of the canyon at the proposed dam site rise abruptly for almost 300 feet. The canyon at the bottom is approximately 250 feet wide. There is only indirect evidence concerning the depth of cover over the rock floor of the canyon bottom. Stream gravels cover most 150 DIVISION OF WATER RESOURCES PLATE XXXII taa^ ui uo!;eA3|2 < Q hi u hi LjJ O ?^ U u. O O^ UJ n a. 1- to u < to Q- O VENTURA COITNTY INVESTIGATION 151 of tho flooi', ])at ill a few places ledges are exposed for almost half of the distance across the gorge. The out-cropping of these ledges would seem to indicate comparatively shallow cover. In no ])lace, however, is ledge rock exposed for the entire distance across the bottom of the canyon. There is always a clogged or buried deeper gorge, but it may not be more than 25 or 30 feet deep. There are many joints. The principal ones are almost vertical, and strike across the canyon almost at right angles to the general course of the stream. In places there are closely spaced groups of joints, probably corresponding to zones of shear. There are no abnormal or special peculiarities, however, about these deformational structures. They are ordinary features to be expected in any region of moderate tilting. There is no fault in the gorge at this site. It is judged that the foundation is sound and sufficiently substantial to support any type of dam. On account of its remoteness from a railroad and the fact that no suitable concrete aggregates for a gravity concrete dam or earth for an earth fill dam are available in the vicinity, a rock fill dam is the only type which was considered for this site. Estimates have been made of the costs of reservoirs with dams 180, 240 and 300 feet in height. Layout of a 240-foot dam is shown on Plate XXXII. All of these dams were located with the center line of the crest in the same position in the canyon. The dam would have a crest width of 15 feet, an upstream slope of 1.3:1, and a downstream slope of 1.4:1. The entire section would be built up of rock dumped in place, with the exception of a layer 15 feet in thickness over the entire upstream face which would be constructed of large derrick placed rocks. The upstream face of the dam would be covered with a concrete facing with a heavy concrete cut-off wall along the toe of the dam, constructed into bedrock. Below this cut-off wall, the foundation rock would be sealed by pressure grouting. The concrete facing would consist of a subslab 12 inches in thickness at the top and increasing one inch in thickness in each 25-foof depth of dam. Over this subslab there would be a laminated reinforced concrete facing composed of slabs 6 inches in thickness. There would be two of these slabs for the first 75-foot depth of dam, and one more slab would be added in each additional 75 feet of depth. The spillway for all heights of dam would be of the side channel type. For the highest dam it would be located on the right side of the canyon and for the two lower dams on the left side of the canyon. The spillway crest would be immediately upstream from the crest of the dam, 180 feet in length, and 25 feet below the top of the dam. The spillway would pass floods of 53.000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, without encroaching on the upper 8 feet of freeboard of the dam. Xo gates would be placed in the spillway and the iioi-mal maximum wafer surface would, therefore, be at the elevation of the sjullway crest. The spillway channel would have widths increasing from 40 feet at the upstream end to 70 feet opposite the downstream end of the crest and would continue with this width to the stream channel. The spillway crest and channel would be lined with reinforced concrete. 152 DIVISION OF WATER RESOURCES The stream would be diverted during construction through a concrete lined tmmel 15 feet in diameter under the right abutment of the dam. There would be concrete lined open cuts at the inlet and outlet ends of this tunnel. After the completion of the dam, this 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 60-inch steel pipe would be laid through this plug and extended through the tunnel to its downstream end. A slide gate would be placed in this pipe just below the plug and a needle valve, for regulating the flow, would be placed at the outlet end. A trash rack structure would be constructed at the inlet end of the tunnel. All of the land in the reservoir, except one small parcel, is owned by the United States Government. It is therefore assumed that the only expense for the acquisition of reservoir lands would be for the purchase of this one 80-acre tract. There are no improvements within the reservoir site which would either have to be purchased or relocated. The dam site is at present inaccessible by road and it would therefore be necessary to build about 10^ miles of new road for the transportation of materials. The rock for the construction of the dam would be obtained from the spillway excavation or from quarries adjacent to the dam. Concrete aggregates and cement would be hauled by truck from Fillmore. It is estimated that 10 to 30 feet of gravel and loose material would be removed from the stream bed and 5 to 10 feet of loose and decomposed rock from the abutments, to obtain a solid rock foundation for the dam. The estimated total costs for the reservoirs with all heights of dams studied are given in the following table : TABLE 36 COSTS OF TOPA TOPA RESERVOIRS WITH ROCKFILL DAMS Crest elevation, in feet' Water surface elevation, in feeti Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 2,265 22,325 2,385 2,240 2,300 2,360 9,790 23,800 46,750 $3,0n,140 4,254,720 6,844,650 $308 179 146 ' Add 56 feet to obtain U. S. G. S. elevation. 'A detailed cost estimate of this reservoir is given on page 236. The same items and similar unit prices were used in estimates of the other dams. Matilija Reservoir The Matiliia Reservoir site is located on IMatilija Creek, a tribu- tary of Ventura River, in Sees. 29 and 30, T. 5 N., R. 23 W., S. B. B. and M., in Ventura County. The dam site for the reservoir is located in the NW^ of the SE5 of Sec. 29. A topographic survey of the reser- voir site was made by the engineering offices of J. B. Lippincott in February, 1926, and a map was drawn from this survey at a scale of one inch equals 400 feet with a contour interval of 20 feet. The water surface areas measured from this map and the capacities of the reser- voir computed from them are shown in the following table: VENTURA COUNTY INVESTIGATION 153 TABLE i7 AREAS AND CAPACITIES OF MATILIJA RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir. in feet, U. S. G. S. datum in acres in acre-feet 970 980 1 1,000 5 50 1.020 10 250 1,040 32 680 1,060 54 1,480 1,080 78 2,800 1,100 98 4,600 1,120 123 6,850 1.140 150 9,550 1,160 179 12,800 A survey of the dam site was made by the State in April, 1933. A topographic map drawn from this survey on a scale one inch equals 100 feet with a contour interval of 10 feet was used in laying out and estimating- the costs of the dams at the Matilija site. The geology of the dam site has been studied by Hyde Forbes but no exploratory work of any kind has been done. The following g'eological data are taken from Mr. Forbes' report: The ^Matilija Dam site lies in a "V" shaped notch eroded from almost vertically dipping sandstone beds. The sandstone is of Eocene ag-e, Tejon, which is the oldest or bottom, and most competent rock, of the Tertiary series of sediments. It is a massive, well cemented arkose sandstone, durable and resistant to weathering- agencies. These massive sandstone beds dip beneath shale beds which extend upstream about a mile from the dam site, at which point Cretaceous shale beds make up the canyon walls. The overturned structure is well exposed at this point and in the shales area intervening between it and the dam site. The deformation and thrust movement within the formation has been so extensive as to produce extreme contortion and weakening of the formation as a whole. ^lany slickensided faces are found in the sandstone. ])robably the result of the massive hard sandstone beds yield- ing- and slipping- along the bedding- planes and joint faces in relieving pressure exerted during the general folding. At the dam site the sandstone strikes northeast-southwest across the stream channel and dips almost vertically, the measured dips ranging from N. 75° W. 75° to N. 85° W. 70° across the stream at stream bed. flattening to 65° to 70° up the abutments. On the ridge above the west abutment, the dip is northerly about 45° and up the North Fork the same beds dip westerly about 60°. The folding of the massive Eocene sandstone and conglomerate contrasts in a marked way with that of the thinly laminated siliceous Monterey shale found along Piru Creek. In the shale, the type of fold produced by the drag of block movement resulted in steep dij^ping, greatly fractured bedded structures, while the more competent sand- stone beds resist deforming pressures and the folds have greater amplitude. There is no major fault closer than two miles from the site and tliat approximately parallel to the axis of the dam. 154 ^•<* DIVISION OF WATER RESOURCES PLATE XXXIII 1 V— — \- \ > ^ o \ >*. » VH in > V E ■s ; — ti in O o O /,; /^ // / ( 4- < < (U Q uJ .(u tr XJO Q < uJ UJ U cr (/^ o O < ^ Q_ -) ° < O _J -3 Q. 1- 5 < s OS a. -• VEXTT'RA COI'XTY INVESTIGATIOX 155 Tlie only type of tlam eonsiclored for this location is the rock fill. Estimates have been made of the costs of reservoir with dams 135. 170 and 205 feet in height. Layout of a 170-foot dam is shown on Plate XXXIII. All of these dams were located with the center line of the crest in the same position in the canyon. The dam would have a crest width of 15 feet, an upstream slope of 1.3:1, and a downstream slope of 1.4:1. The entire section would be built up of rock dumped in l)lace, with the exception of a layer 15 feet in thickness over the entire upstream face which would be constructed of large derrick placed rocks. The upstream face of the dam would be covered with a con- crete facing with a heavy concrete cut-off wall along the toe of the dam, constructed into bedrock. Below this cut-off wall, the foundation rock would be sealed by pressure grouting. The concrete facing would con- sist of a subslab 12 inches in thickness at the top and increasing one inch in thickness in each 25-foot depth of dam. Over this subslab there would be a laminated reinforced concrete facing composed of slabs 6 inches in thickness. There would be two of these slabs for the first 75-foot depth of dam. and one more slab would be added in each addi- tional 75 feet of depth. The spillway would be an open cut through the ridge between Matilija Creek and its North Fork, about 1500 feet upstream from the dam. Material taken from this cut could be used in the construction of the dam. In addition to the cut through the ridge, some widening and deepening of the North Fork channel would be necessary. There would be a 10-foot weir 83 feet in length, with its crest 25 feet below the top of the dam. at the inlet to the spillway channel. This weir would have a capacity of 27,250 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, with a 5-foot net freeboard on the dam. No gates would be placed in the spillway' and the normal maximum water surface would therefore be at the elevation of the crest of the weir. The channel would have a 72-foot bottom width and would be lined with reinforced concrete. The stream would be diverted during construction through a con- crete lined tunnel 10 feet in diameter under the left abutment of the dam. There would be concrete lined open cuts at the inlet and outlet of this tunnel. After completion of the dam, the tunnel would be used for the outlet from the reservoir. A concrete plug would be placed in the upper end of the tunnel and a 36-inch steel pipe would be laid through this plug and extended through the tunnel to its downstream end. and upstream from the plug to the stream channel. The portion outside of the tunnel would be laid in an open cut and encased in con- crete. A slide gate would be placed in the pipe just below the tunnel plug and a needle valve, for regulating the flow, would be placed at the outlet end. A trash rack structure would be constructed at the inlet to the pipe. All of the land in the reservoir is privately owned and it is esti- mated that about 300 to 400 acres would have to be acquired. There are also some buildings on these lands and these would be acquired with the land and would not have to be relocated. It is estimated that to obtain a firm rock foundation for the dam. it will be necessary to remove about 15 feet of gravel and boulders in the stream bed and 8 feet of broken and decomposed rock over the abutments. The rock for 156 DIVISION OF WATER RESOURCES the construction of the dam could be obtained from the spillway channel or from quarries adjacent to the dam. Aggregates for the concrete would be hauled from Santa Paula by truck, and cement would be liauled from the railroad at Ojai. The estimated total costs for the reservoirs with all heights of dam studied are given in the following table : TABLE 38 COST OF MATILIJA RESERVOIRS WITH ROCK FILL DAMS Crest elevation, in feet, U. S. G. S. datum Water surface elevation, in feet Capacity of reservoir, in acre-feet Capital cost Cost per acre-foot of capacity 1,120 ■1,155 1,190 1,095 1,130 1,165 4,100 8,150 13,700 S2,599,000 2,329,000 3,270,000 S634 286 . 239 'A detailed cost estimate of this reservoir is given on page 237. The same items and similar unit prices were used for the other dams. Cost of spillway for the lowest dam is large because for this dam the open cut through the ridge in- volved heavy excavation and makes the total cost of reservoir larger than for the reservoir for which detail cost estimate is given. Camarillo Reservoir The Camarillo Reservoir site is located on Conejo Creek in lots 39, 40, 41, 42, 43, 48 and 49 of the Rancho Calleguas, in Ventura County. The dam site for the reservoir is located in lots 39 and 40. A topographic survey of the reservoir was made by the State in ]\[arch, 1933, and a map was drawn from this survey at a scale of one inch equals 400 feet with a contour interval of 5 feet. The water surface areas measured from this map and the capacities of the reser- voir computed from them are shown in the following table : TABLE 39 AREAS AND CAPACITIES OF CAMARILLO RESERVOIR Elevation of water surface. Area of water surface. Capacity of reservoir. in feet, U. S. G. S. datum in acres in acre-feet 165 4 10 170 7 36 175 27 122 180 66 357 185 118 818 190 163 1,520 195 190 2,400 200 239 3,470 205 291 4,800 210 348 6,390 215 406 8,280 220 457 10,400 225 507 12,800 The survey of the dam site was also made by the State in March, 1933. The topographic map drawn from this survey on a scale of one inch equals 100 feet wdth a contour interval of five feet w'as used in laying out and estimating the cost of the dam. A preliminary study of the geology of the Camarillo Dam site has been made by Chester Marliave and a number of holes were bored across the dam site to determine the depth to firm foundation material. The following data on the geology have been taken from his report : VENTURA COUNTY INVESTIGATION 157 Tlie left ahutniciil of the cbnii site is a n L « u / o // \\ 1 1 1 1 f I ' ; j \\ II Q UJ DC L. ^- O a d) O o o. , in ,*-* y ^ 'l V S , ui '7 ki S 1/ o / -1 / i f' ' / k- ^ ' '-"^ 'I ' £ 1 J V t: in \ .3 \ 01 ) L /* a-' OJ \ c OJ o Ao ^ 1 I 1 < o ll. o. c z ■ o H U Q UJ CO O Q. O a: Q. < cc < < o o i99j ui uo!ieAa|3 VENTURA COUNTY INVESTIGATION 159 thick would be constructed through the center of tlie dam. This wall would be carried throuj^-h the surface material on both abutments to the firm underlying material, into which it would be keyed. For a distance of 85 feet to the right, and 185 feet to the left of the center line of the stream channel, where there is a porous alluvial fill of 15 to 50 feet, the core wall would be constructed of concrete only above the ground surface and would be extended to the firm underlying material by a row of steel sheet piling driven through the alluvium. The spillway would be located in a saddle on the left side of the reservoir about 1000 feet upstream from the dam. The bottom of the cut through the saddle would be at elevation 215 feet, or 20 feet below the top of the dam. There would be no gates in the spillway and the normal maximum water surface would therefore be at the elevation of the spillway crest. The channel would have a bottom width of 100 feet with side slopes of 1 :1. It would be lined with reinforced con- crete for a distance of 280 feet from the inlet end. The spillway capacity would be 10,000 second-feet, the. estimated crest flow of a flood which may occur once in 1000 years on the average, with a net free- board of 10 feet on the dam. The outlet from the re.servoir would be ]ilaced under the left side of the dam near the base of the steep slope. It would consist of a 36- incli steel pipe encased in concrete and would be laid in an open cut excavated to firm foundation material. Water would enter the pipe through a concrete inlet tower which would be provided with two slide gates. All of the land in the reservoir is privately owned and most of it is under cultivation. There is a county road along the right side of the reservoir, low points in which would be raised by earth fills to bring the entire road surface above the high water level of the reservoir. Material for the earth fill for the dam would be obtained from the re.servoir near the dam site. Sand and gravel for concrete would be obtained from Saticoy and hauled 14 miles by truck. Cement and other materials would be hauled five miles by truck from the railroad at Camarillo. A detailed cost estimate of the reservoir totaling $808,000 is shown on page 238. Dunshee Reservoir The Dunshee Reservoir site is located on Coyote Creek in the Rancho Santa Ana. in Ventura County. The dam site for the reservoir is located about five and one-half miles above the junction of Coyote Creek with the Ventura River. A topographic survey of the reservoir site was made by E. E. Everett in August, 1931, and a map was drawn from this .survey at a scale of one inch equals 200 feet with a contour interval of 10 feet. The water surface areas measured from this map and the cai)acities of the reservoir computed from Ihem are shown in Table 40. A survey of the dam site was made by E. E. Everett in August, 3933. A topogra])hie map made from this survey on a scale of one inch equals 50 feet with a contour interval of five feet was used in laying out and estimating the costs of the dams at the Dunshee .site. 160 DIVISION OF WATER EESOURCES TABLE 40 AREAS AND CAPACITIES OF DUNSHEE RESERVOIR Elevation of water surface, Area of water surface, Capacity of reservoir, in feet' in acres in acre-feet 110 4 40 115 10 75 120 15 125 125 21 200 130 2S 350 135 35 500 140 45 700 145 54 90C 150 62 1,200 155 74 1,500 160 84 1,900 165 95 2,400 170 100 2,850 175 106 3,350 180 112 3,900 185 120 4,500 190 130 5,100 195 140 5,800 200 149 6,500 205 154 7,100 210 168 8,000 215 183 8,900 220 200 9,900 ' Add 30!i.7 feet to obtain U. S. G. S. elevation. A preliminary examination of the geology of the site has been made by Chester Marliave. The following data have been taken from his report : The reservoir would occupy an area covered by thick deposits of gravels and clays heterogeneously mixed. It is believed that stored water would not be lost by subterranean seepage. The vicinity of the dam site is a region of Tertiary sediments con- sisting of soft sandstones, clay shales and some conglomerate probably belonging to the Vaqueros, Sespe and Modelo formations. At the site the rock exposures are medium grained, fairly well cemented sand- stones which alternate with clay shale beds. The sandstones occur in rather massive beds varying from several feet to 40 feet in thickness, but seldom exhibit a ring when struck with a hammer. They are some- what fractured near the surface but tighten shortly below it. Appar- ently they are not crushed or distorted but in places are somewhat softened by water. The exposed shales in the trenches at the dam site are in beds varying from 1 foot to 12 feet in thickness. They do not show any appreciable amount of gypsum. From observation of the bedding planes it is believed that there is an anticlinal fold with its axis passing clown the canyon through the dam site. On the right side of the canyon the strata indicate a uniform monoclinal dip downstream but the beds of the left abutment appear to have turned over in a gentle anticlinal fold with a break occurring about 50 feet above the stream bed. For a short distance above this break there is a shelf about 100 feet wide Avhieh gives the ai)])earanee of a slide or break through this abutment. On the right abutment of the dam site a thick hard bed of sand- stone outcrops along the lower slope of the bank having an exposed thickness of about 12 feet while above it in the two trenches which VENTURA COUNTY INVESTIGATION 161 were dug on that abutment the shale beds alternate with the sand- stones. These beds are nniformly tilted without evidence of folding. Upstream from the axis of the dam site there is an exposure of sand- stone the attitude of which likewise shows a similar position indicating the uniformity of structure on the right abutment. The left abutment shows a thick stratum of sandstone in the trench dug along the axis of the proposed dam. This stratum extends to a height of 50 feet above stream bed and above it occurs the break mentioned before. Above the break there are shale beds. At a point 70 feet above stream the rock surface dips and the trench exposes only an old terrace deposit of gravel and boulders. No suitable material for a rock fill dam occurs in the vicinity of the site. There is, however, ample material for an earthen dam within reasonable haul. Stripping would probably have to be done to an average normal depth of 15 feet on the sides and the stream gravels might have a maximum depth of 40 feet with an average of 20 feet across the 180-foot bottom. The exploration work consisted of trenches on each abutment and a pit in the bottom which struck bedrock at 14 feet but it is believed that the bedrock would be found at a greater depth further from the canyon wall. It is believed that the most suitable type of dam for this location is the earth fill. This type was therefore selected for estimating the costs of the reservoirs with dams 90, 120 and 135 feet in height. All of these dams were located with the crest or axis line in the same posi- tion in the canyon. The dam would have a crest width of 20 feet, an upstream slope of 2.5 :1 and a downstream slope of 3 :1. Layout of a 120-foot dam is shown on plate XXXV. All of the downstream sec- tion lying between the downstream face and a plane on a slope of 1 :1 from the downstream crest line would be of pervious material. Under this section of the dam no excavation, except for the removal of loose surface material, would be made. The remainder of the dam would be constructed of impervious material compacted either by the hydraulic process or by rolling. Under this section of the dam, all loose material would be excavated to a firm rock foundation. The upstream face of the dam would be protected by a 6-i2ich layer of reinforced concrete terminating in a small toe wall set into the solid rock at the toe of the dam. A low^ dyke in a saddle about one-half mile northeast of the dam site on the left side of the reservoir would be required for all dams with a crest elevation exceeding 515 feet. The dyke would have a crest width of 20 feet, a water side slope of 2 :1 and a downstream slope of 3 :1. The water side face would also be ])ro- tected by a 6-inch layer of reinforced concrete. The spillway would be of the straight channel type excavated through the ridge forming the right abutment of the dam. The weir in this channel would be 100 feet in length and 15 feet below the top of the dam. The spillway could pass a flood of 9000 second-feet, the estimated crest flow of a flood which may occur once in 1000 years on the average, without the water surface in the reservoir encroaching on the upper six feet of freeboard of the dam. No gates would be placed in the spillway and the normal maximum water surface would 11 — S367 — 8375 162 DIVISION OF WATER RESOURCES PLATE XXXV o O UJ X in z o u a: O z O liJ I- O >- o o (^ r o> ^ i ■D b > [- 8 o o m N, auueq:) ^eM]|id / / .11 C U. ;j 4.aaj ui uO!4eAai3 VEXTURA COUNTY INVESTIGATION 163 therefore be at the elevation of the spillway erest. The spillway ehaiiiiel would extend to the ereek ehaimel at a point several iiundred feet below the dam. The spillway channel would be lined with rein- forced concrete. The stream would be diverted durin«i' construction tliroujih a con- crete lined tunnel 10 feet in diameter extendino- tlirou u 720 Cres t of levee elev 774 T n ~ ■\Ground surface-, ^.^ -16' radial iates-K ieiev75l' y\ 1 1 1 f" ;^ r.^ ^Crest of dan Stripping line — -" ~T~T\ ULJJ ■ --, - > 1 . -1 — : — r_i .-> \"" -■\ -- ;f--i •- "i"j \ Bott 1 3m of cut-off wa 1 1 1 1 TUNNEL SECTION Length m feet PROFILE OF DAM^LOOKING UPSTREAM STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION PROPOSED SPREADING WORKS NEAR PIRU VENTURA COUNTY INVESTIGATION" 171 Montalvo Basin A diversion dam with four 55-foot width floodway openings is proposed at the present site of the Lloyd-Butler Ditch intake. The bottom of these openings would be approximately two feet above the river bed and flood water levels would be increased but little. Roller- crest control would enable the water level to be raised four feet above the permanent crest, to elevation 156. The structure would include extraordinary provision against destruction by erosion. Cut-off walls and sheet piling to a depth of 20 feet below the river bed and reinforced concrete piling under the piers to a depth of 35 feet are proposed. A 20-foot by 6-foot taintor gate would provide a sluiceway adjacent to the canal intake and a smaller taintor gate would control the canal intake. On the north bank it would be necessary to extend a protected levee a few hundred feet upstream and one or two hundred feet down- stream. On the southerly bank it is proposed to extend levee and bank protection from the diversion dam downstream along the desilting basins which would adjoin the river on the south. A concrete lined canal with a capacity of 400 second-feet with bottom width of 15 feet, water depth of 5 feet, side slopes 1^ to 1, and grade of 0.00025 would extend to the desilting basins. Control gates would regulate the flow three ways : to the basins, to Lloyd-Butler Ditch (or Camarillo Canal proposed as part of the ultimate county plan), and to the spreading grounds direct through a concrete lined bypass canal. Provision of 530 acre-feet of storage for desilting the flood flows of the Santa Clara River water prior to spreading would be provided by two parallel desilting basins. The division levee and required structure in separating the storage into two basins add about $20,000 to the total cost but the opportunity for more flexible operation and the increased safety against interruption of spreading appear to justify the added cost. The larger basin adjacent to the river would have an area of 43 acres, a capacity of 280 acre-feet and a maximum water depth of 12 feet. The other, an area of 39 acres, a capacity of 250 acre-feet and a maximum water depth of 13 feet. The levee sections for the basins would be similar to those for the Piru spreading works, but the fills would include a considerable volume of cobblestone. With some additional cost these might be used for riprapping portions of the levees where concrete paving and flexible wire me.sli construction would not be required for protection against river erosion or they could be used as wave protection on the inside of the levee. Freeboard on the levees forming the basins would be three feet. Large outlet pipes leading to the river would provide for sluicing sediment out of the desilting basins. This would be facilitated by strip levees which lead to a lip on concrete channels which discharge into the outlets. Flashboard controlled sluices at the upper end of the basins would make it possible to sluice the individual strips. Outlets from the basins would be a combination of overflow spill- way and deeper flashboard controlled sluices discharging into a con- 172 DIVISION or WATER RESOURCES PLATE XXXVIII VENTURA COUNTY INVESTIGATION 173 Crete lined collection canal which would connect with the main dis- tributing canal at the lower end of the bypass canal. The concrete lined bypass canal from the upper to the lower end of the desilting basins would have a capacity of 220 cubic feet per second, bottom width of 6 feet, depth 3 feet, side slopes 11 to 1 and grade 0.0025. From the levee end of the bypass canal a concrete lined canal 6 feet bottom width, 25 feet depth, 1^ to 1 side slopes, grade 0.003, 200 second-foot capacity, would pass through the spreading area lying above Del Norte Avenue. At the lower end of this spreading area the canal would be provided with a w^asteway, discharging into the river bed and with an outlet to 120 second-feet canal extending down Vine- yard Avenue to the spreading area below Del Norte Avenue. The estimated cost of preparing the spreading grounds is based upon ponding in from one- to ten-acre blocks, with maximum water depth of about two feet. The outside levees and some interior ones would be wide enough for roadways. Strip levees with channel flooding could be provided for most of the area W'ith no increase in cost over the proposed plan. Approximately 250 acres of spreading area are proposed of which 135 acres are above Del Norte Avenue and 115 acres below it. Additional areas could be secured in the river wash above Saticoy Bridge. Capacity- of works is based on absorption in the spreading grounds of two feet in depth per day. Upper Ventura River Basin The location selected for the spreading development is the highest practicable one on the Ventura River, with a diversion dam located 1800 feet below the present diversion of ^Matilija Ranch. The river bed elevation at the proposed diversion site is 764 feet. A rubble concrete masonry structure ^^^th old steel rails surface pro- tection is proposed, with a crest elevation of 768 feet. The structure would be provided by a stilling pool with a flexible concrete mattress below it. Headgates for the spreading works diversions would have a total sill length of 32 feet and a depth of 2 feet below the crest of the dam. A 16-foot sluiceway with a sill 4 feet below the crest of the dam would be closed by a radial gate. A guide levee on the west side of the main channel would extend upstream from the end of the dam to the existing levee protection of the Rancho Santa Ana diversion works. Its crest elevation at the end of the proposed diversion would be 780 feet. In order to avoid exces.sive spillway capacities for the main flood- ing levees, it is desirable to bypass the flood flows of the Cozy Dell Creek. By means of a diversion levee the flood flow of this creek may be kept in the most northern channel of its cone and carried across a covered section of the spreading works channel. From the diversion dam to the southern end of the spreading grounds, a low road levee is proposed. In general it would be built on the highest ground lying between the main river channel and the spreading grounds. This would provide a considerable measure of protection from flood menace, and would provide access for the con- struction of flexible mattresses or other protection works at the threat- ened point. 174 DIVISION OF WATER RESOURCES PLATE XXXIX /•^-~*- VENTURA COUNTY INVESTIGATION 175 Main flooding levees would be constructed with top widtli of 18 feet and would be smoothed for roadways. The control structures would have ''single lane" bridges over them. Guides of 4-inch, H- beams section would be provided for flashboard or gate control. Half of the 20-foot spans of the control openings included in the estimates and shown on the plan would be for use as overflow spillways and would have weirs without provision for flood-board control. It is possible that some other type of spillway could be constructed at less cost. The area flooded by these main levees, as shown, would be 50 acres and the volume of storage 127 acre-feet with a maximum water depth of about 9 feet for the larger basins. The mean depth for the entire flooded area would be 2.5 feet. On an area of about 90 acres it is proposed that contour levees be constructed to a height of about 3 feet, with one foot freeboard. The average distance between 2-foot contours for this area is about 32 feet and therefore an average of little more than one-quarter of a mile of levee would be required for each acre flooded. These levees may be constructed by the use of a Martin Ditcher or by a road grader. CHAPTER XIII PLAN OF DEVELOPMENT SANTA CLARA RIVER VALLEY, COASTAL PLAIN AND CALLEGUAS CREEK VALLEY Hydrological Resume As an introduction to a plan for development a brief resume of the hydrology of these areas follows: The water supply of all the above areas is derived by pumping underground water which has penetrated by percolation from streams, or from rainfall on the valley floor. In addition to these sources, there is a supply produced by deep percolation of rain on the porous portions of the watershed above the valley in those areas where these formations also underlie the recent alluviums of the valley and transmit the water which has thus percolated to a point beneath the valley wiiere it becomes available to pumps penetrating the alluvium or the porous older formation. Water from this source is believed to be a consider- able item in all the basins of Calleguas Creek drainage area. Informa- tion sufficient to evaluate this supply is not available and hence no attempt has been made to calculate the surplus or shortage in Simi, Santa Rosa, West Las Posas, Las Posas, and Pleasant Valleys. It may be that present draft in Pleasant Valley and in the northern part of Simi Valley is greater than the long time average and that local sources are insufficient, which condition, if it exists, will eventually necessitate tlie importation of water if present agricultural develop- ment is maintained. In the other valleys above mentioned it is believed supply is equal to or greater than present demand but evaluations of supply have not been attempted. Use of irrigation water has been rapidly increasing in the recent past and rainfall has been deficient, either of which is sufficient to cause the water table to fall as it has done even without long-time deficiency. This obscures the true con- dition of these valleys. Very little water from this drainage area wastes into the ocean, indicating that little conservation can be accomplished by reservoirs in the watershed or by spreading operations. In Santa Clara River Valley natural percolation without conserva- tion is sufficient for present irrigated area and for ultimate expansion with a large margin to spare for a forty-year period similar as to pre- cipitation to that beginning in the fall of 1892. With present irrigated area the average annual waste out of the valley for the 40-year period is estimated to have been 177,000 acre- feet of which 27,000 acre-feet was water which had percolated to the water table and reappeared at the lower end. The remainder was flood waste. (176) VENTURA COUNTY INVESTIGATION 177 The estimutecl Jiverajiv nniiiuil wjisti' from the valk'V in tho ten years of drought beginning with 1922 is 73,000 acre-feet of which 52,000 acre-feet occurred in flood flows. Not all of the discharge from Santa Clara River Valley wastes into the ocean. Most of the rising water and part of the flood flow again j)ercolate and is the prinei])al supply to Oxnard Plain. Estimates of the sup]ily to Oxnard Plain indicate that the long- time average is slightly less than pumping draft which occurred during the dry years of the investigation. A difficulty in Oxnard Plain may be prevention of intrusion of salt water from the ocean into the pump- ing strata as the water table lowers during long periods of drought. With present irrigated acreage and draft as it occurred during the investigation it is estimated that in a diy period similar to that which began in 1922 the requirement for this would be 9000 acre-feet annually on the average. For possible ultimate development it is esti- mated that this would require 17,000 acre-feet for a similar draft. It may be found in a recurrence of normal or above normal years of rainfall that the draft will be less which would reduce the foregoing estimates. Discharge from the mountains is highly erratic. In the past forty years the period from 1893 to 1904 was one of drought, the period from 1905 to 1918 was one of prolific run-off and the period from 1919 to 1932 was again deficient. Records of precipitation indicate that prior to 1892 cyclic variation also occurred. In addition the annual variation is great. The estimated run-off of Santa Clara River for the most prolific year is over forty times the estimated run-off of the most deficient. Such a condition necessitates excessive storage capacity if a. large percentage of the waste is to be conserved as to do this requires that the Avaste of prolific cycles be held for use in deficient cycles. The Problem Stated The problem presented is to so regulate and control the surplus of Santa Clara River Basin that it can be transported to the areas to the south now deficient or which may become deficient. Facilities avail- able for control are surface reservoir sites on Piru and Sespe Creeks and the natural underground reservoirs now available in Piru Basin and Montalvo area as shown on Plate I, page 16, and Plate XXXVI, page 166, or underground space created by pumping. In both the areas mentioned the water table is sufficiently below the surface in dry cycles of years so that large reservoir capacity is available and conditions are favorable for artificial recharge. Once placed in under- ground reservoirs evaporation losses may be held to a minimum by proper manipulation while in surface reservoirs such loss is large if water is held over long periods. Two general routes are available for transportation of the water to the south. One would transfer water across South Mountain at a point near the town of Fillmore in Santa Clara River Valley and land it on the other side in the general vicinity of the town of Moorpark. Pressure pipe lines, high pumping lifts and tunnels would be required. The area nearest the outlet would be the Moorpark-Somis area, that is. Las Posas Valley and the upper part of Pleasant Valley. The other i 12 — 8367 — 8375 178 DIVISION OF WATER RESOURCES PLATE XL i£-oe 92-SZ ^ 13-03 Q) E a> -t- Q. CU CO (1) J3 P o 1 11-01 ro 0) >) To c in 90-SO TO 0) 10-0061 96-S6 s. RUNOFF MASS DIAGRAM PIRU CREEK AT LOS ALAMOS DAM SITE SEASONAL YEAR ENDING SEPTEMBER 30 \ \ \ \ 'v V \. s \, ' N ^ \ L \^. \ K% \ \\ \ % Vj "» V \ f-. \ , Vl , »=». >-»joe ooO'iVZ >. s \ v. — * % V N"^ \ \ v_ '\ \ \ \ \ 1 \ \ \ v_ -^ \ V » ^ L_ ^ \ \ i \ \ V '^ c 1 > 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 o o o » to IV. lO lO M- (^ +a8^-8Joe u! ^^o-uny 200.000 100.000 D VENTURA COUNTY INVESTIGATION 179 route would carry the water around the end of South Mountain after Santa Clara River Valley had secured its full demand. A gravity conduit would reach well to the eastern part of Pleasant Valley, (Plate IV, opposite page 26.) Santa Rosa Vallej^ and the lower areas in the vicinity of Moorpark could be reached with comparatively small pumping lift. Most of the Oxnard Plain could be reached without artificial conduit, the water being transported underground through the aquifers as it is in a state of nature. Detail cost estimates were made of the second but not of the first plan. Surface Reservoirs Xo favorable reservoir sites exist on Santa Paula Creek. The work done on the sites on Piru Creek and Sespe Creek is discussed in detail in Chapter XI which gives careful estimates of cost of each reservoir with different types of dam and different capacities. For the reservoirs on Piru Creek the curves indicate that for a capacity of 30,000 acre-feet the cost per acre-foot of capacity would be approximately as follows : Spring Creek $108.00 Devil Canyon 135.00 Los Alamos 140.00 Blue Point site was estimated only for smaller capacities because of bad foundation conditions involved for a higher dam. At lower capacities the cost per acre-foot for Spring Creek becomes still more favorable relatively but at 40,000 acre-foot capacity Devil Canyon becomes the cheapest per acre-foot of capacity. On Sespe Creek estimates were made for only Cold Springs and Topa Topa sites which show the former to be much cheaper per acre- foot of capacity than Topa Topa and cheaper for any capacity above 14,000 acre-foot than any of the reservoirs on Piru Creek. On Plate XL is shown a cumulative mass curve of run-off at Los Alamos site on Piru Creek. To maintain a draft of 27,000 acre- feet per year would require a capacity of 245,000 acre-feet. X^o such capacity is possible from a physical standpoint and equally impossible from the standpoint of cost. Water would be held over in the reservoir for more than a quarter of a century and approximately half of it would be lost by evaporation leaving a usable yield of only 14,000 acre- feet. This curve is typical of all storage sites whether on Piru Creek, Sespe Creek or on Ventura River. At Devil Canyon a capacity of 525,000 acre-feet would be required to give a u.sable vield of about 28,000 acre-feet. From this analysis and because of the small reservoir capacities as shown by surveys and the large cost per acre-foot as shown by esti- mates it is concluded that, if built, surface reservoir capacities should be only sufficient to control the waste of the dry cycles. The ten and half-year period from spring 1922 to fall 1932 was therefore selected for study. A similar deficient period occurred from 1893 to 1904 but data are more reliable for the later period and during five years of it the investigation was under way giving opportunity to intensively observe all hydrological phenomena. 180 DIVISION OF WATER RESOURCES PLATE XX.I 0) I U c tn 3 O c o l- c o u "r5 c c 14 12 10 Spreading after storm periods only, combined with reservoir.^. ^. / ^ — / 1 Additional conservation Y /spreading after storm p with reservoir eriods only. \ " 10 c IE UJ g o l^ tE i o FCONS AND TY OF ON CREEK EET SPREA 1- S Eo >~. 1 /\ / t/5 <£ H o NIT CO UIRED C ITH 200 S o \ c \ \\ 1 ZD Cf ^ a. UJ Ol oc \ L \ \ N i \ V // \ vX « X\ / / \ \ •^ \\ ' / \ \ / W / \ \ > ' ^\\ \) / V ^ +- z' ^ /^ ^ I ,/ ^ y / \ y^ v Q. y* '"■vt \\ a) 3 !.-"' ,-v / ^ S,^ \^ OQ ^^' ' ^^'' y \ N>. Y \^^ ,^ ^1^^ y^ ^ ,V /) 7 -.-'^\ t^" ^V / ^,-«''' ^ X w Y^ /, \/, / ^******'^ K^ \ ^ \\y c <3 ■s \ ^ A S s E .s Q £ TO <: 5 < in ^ sje||Op u!'uoi;eaj9suoo jo |ooj-9JDe jad iso^ VENTURA COUNTY INVESTIGATION 183 TABLE 43 PIRU CREEK CONSERVATION— SPREADING WORKS ALONE AND IN COMBINATION WITH DEVIL CANYON RESERVOIR, 30,000 ACRE-FOOT CAPACITY Acre-feet conservation— average per annum, 1922-32 Second-feet spreading capacity Spreading works alone Additional by Devil Canyon Reservoir Combined Devil Canyon Reservoir and Spreading 100 200 300 400 3,780 4,770 5,230 5,540 9,170 6.570 5,770 5,470 5,240 9,170 10,350 10,540 10,700 10,780 Incidentally the first figure under the heading "Additional by- Devil Canyon Reservoir" is the yield of a reservoir of that size without spreading. From the cost estimate of the reservoir the cost per acre- foot of salvage by reservoir alone can be calculated. In the following table this is shown together -with the same information for Spring Creek Reservoir for which a similar study was made. TABLE 44 COMPARATIVE COST AND AMOUNTS OF CONSERVATION, SPRING CREEK AND DEVIL CANYON RESERVOIRS WITHOUT SPREADING Acre-feet Cost Name Approxi- mately most economic capacity Conserva- tion, average, 1922-32 Total Per acre- foot of conservation Sluing Creek 15.000 30,000 4,900 9,170 11,550,000 3,600,000 $316 Devil Canyon 392 Note. — The Spring Creek Reservoir cost is for the cheapest type of several dams on which estimates were made. Only one type of dam was used in estimates for Devil Canyon. After consideration it was decided that further studies should be on the basis that spreading works could be made to function on all days when water was available and that the diversion would be 200 second-feet although as explained in Chapter XII the diversion capacity would actually be 300 second-feet. All subsequent studies are based on spreading 200 second-feet. In these studies water is assumed to be held in the reservoir only w^hen the discharge exceeds 200 second- feet plus natural stream bed percolation. Plate XLII shows the unit cost of conservation of all reservoirs investigated on Piru Creek, assuming that they salvage only the water which could not be salvaged by spreading. The lowest point on the curves also shows the most economic capacity of each reservoir. The following table is taken from the supporting data for these curves. 184 DIVISION OF WATER RESOURCES TABLE 45 PIRU CREEK, COMPARATIVE COST OF CONSERVATION BY RESERVOIRS, SPREADING GIVEN PRIORITY Name Approxi- mately most economic capacity, acre-feet Total cost Conserva- tion, acre-feet Cost per acre-foot, conservation Los Alamos with Liebre Creek diverted to it Spring Creek Blue Point . 11,600 15,000 ♦20,000 30,000 $1,710,000 1,550,000 3,500,000 3,000,000 3,000 3,470 4,800 5,770 J570 455 730 625 Not most economic but capacity limited by geological conditions. Sespe Creek The results of various studies of amount of conservation of Sespe Creek water which could be effected by reservoirs of various capacities, spreading works at Montalvo Basin of various capacities and combina- tions of the two, are shown on plates in the same way as the same information was shown for Pirn Creek. All studies on Sespe Creek are also for the deficient period 1922—1932. The plates on pages 120 and 122 give total cost of all reservoirs with diff'erent types of dams and costs per acre-foot. As with Piru Creek it is cost per acre-foot of yield which is important and not cost per acre-foot of capacity. In estimating yield the reservoirs on Sespe Creek were assumed to be emptied in the same way as those on Piru Creek and the discussion on page 181 applies equally to Sespe Creek conservation. Plate XLIII shows the average acre-feet of water from Sespe Creek which would be conserved by spreading works of various capac- ities diverting from Santa Clara River in the Montalvo area near the town of Saticoy, alone and also combined with surface reservoirs on Sespe Creek. Curve 1 shows the estimated conservation if spreading can be done on all days when the water would not naturally percolate. Curve 2 shows the estimated conservation if spreading could not be done during floods and until the stream had settled to a steadily decreasing flow thereafter. In estimating the days on which spreading could not be done the run-off of each year of record was inspected and for those years in which no records are available a proportionate number of days allowed depending on the flood discharges of Sespe Creek for which records are available. The average number of days per year in which it was assumed that no spreading would be attempted is six and one-half but in some years it is much more. As a basis for further studies it was assumed the accomplishment of the spreading works would be based on 200 second-feet diversion not operated during flood periods. Curve 3 shows the combined annual conservation accomplished by Cold Spring Reservoir, capacity of 40,000 acre-feet, combined with spreading works if they could function all days when water was present. Curve 4 shows the amount of conservation in the combination VENTURA COUNTY INVESTIGATION 185 due to the reservoir. Curves 5 and 6 give the same information, respec- tively, for Cold Springs R-eservoir built to 40,000 acre-foot capacity and Topa Topa built to 20,000 acre-foot capacity. The supporting data for these curves are given in the following tables : TABLE 46 SESPE CREEK CONSERVATION— SPREADING WORKS ALONE AND IN COMBINATION WITH COLD SPRING (40,000 ACRE-FEET) AND TOPA TOPA (20,000 ACRE-FEET) RESERVOIRS Conservation— acre-feet— average per annum, 1922-1932 Second-feet spread iog capacity Spreading works alone Additional by Cold Spring Reservoir Combined Cold Spring and Spreading Additional by Cold Spring and Topa Topa Reservoirs Combined Cold Spring and Topa Topa and Spreading 100 200 300 10.300 12,600 14,500 11,500 9,500 8,600 8,000 11,500 19,800 21,200 22,500 22,000 18,700 18,600 16,600 22,000 29,000 30,200 31,100 Note. — Spreading works not operated during floods. Incidentally the first figures in the two columns which show con- servation by reservoirs alone are the yields of the reservoirs of that size without spreading and from the cost estimate of the reservoirs the cost per acre-foot of salvage by reservoir alone can be calculated. TABLE 47 COMPARATIVE AMOUNTS OF SALVAGE, COLD SPRING RESERVOIR ALONE AND COMBINATION OF COLD SPRING AND TOPA TOPA RESERVOIRS WITHOUT SPREADING Name Approxi- mately most economic capacity, acre-feet Total cost Conserva- tion, acre-feet Cost per acre-foot of conser\-ation Cold Spring 40.000 $1,920,000 11,500 22.000 $167 40,000 20.000 $1,920,000 3,860,000 Topa Topa... 60,000 $5,780,000 263 Plate XLIV, page 187. shows the unit cost of conservation for different capacities in combination with spreading works of 200 second- feet capacity at Saticoy not operating during floods and assuming that the reservoirs salvage only water which could not be salvaged by spreading works without reservoirs. Most of the information is for a 40,000 acre-feet reservoir at Cold Spring combined with various capacities at Topa Topa. However, a study was made of a 30,000 acre-foot reservoir at Cold Spring site combined with a 30,000 acre-foot reservoir at Topa Topa and the results are shown on the graph. This increases the yield but also the unit cost. The plate also shows the most economic size of reservoir. 186 DIVISION OF WATER RESOURCES PLATE XLIII U TO O (/) T3 C ro If) o c o 30 ^^ -^ ■XD- 28 / -^ / ^""^ — ^Spreading' after storm periods witti Cold Spring and Topatopa reservoirs 26 / / / 24 / / 22 Spreading after storm periods with Cold Spring reservoir^ ^ .^ ^ >- 20 \ \^ ^ J©- ^ N > K itiona ngan conse d To pa rvatio topa ^ with reserv Cold sirs y 18 / / ^ -< Spr y / iS)- ^^ -~~ -7^ / 16 / / /^ "^ / Spreading all da^s without reservoir- * > f ^ 14 / / / / / ^ 12 / / jdT X'*^^^Spreading after storm periods without reservoir \ ' / ^ ^' 10 \ ^ y y / f^ -<§x. -<' ^^Additional conservation with Cold Spring reservoir a / "^"^ -- 100 200 300 Spreading capacity in acre -feet SANTA CLARA RIVER MEAN ANNUAL CONSERVATION FOR PERIOD 1922-1932 AVAILABLE BY SPREADING NEAR SATICOY AND WITH RESERVOIRS ON SESPE CREEK 40,000 ACRE-rEElT CAPACITY AT COLD SPRING AND 20,000 AT TOPATOPA VENTURA COUNTY INVESTIGATION 187 PIRATE XLIV A80 A60 440 .20 O -D AOO ■^ 380 > O 360 O 8 3^° <+- l_ o ns 320 o 300 280 Conservation in thousands of acre-feet 6 8 10 12 14 16 18 260 240 220 \ \ i 1 ] \ \ UNIT COST OF CONSERVATION AND REQUIRED CAPACITY OF RESERVOIRS ON SESPE CREEK 200 SEC.-FI SPREADING AT SATICOY AFTER STORM PERIODS ONLY \ \ I \ \ \ \ \ \ y^ Capacrty Conservation 1 V \ \ \ V > V \ ^Topatopa / \ / \ \ > / / 1 \ / \ >< / / 1 i loS^s^^ /^ '^ — ^/ Combin ' 1 ed storage'^ 30- / Tho jsands of acre -feet in Topa remainder in Cold Spring topaf' ^ V Nc / 15 ■ i 1 v\' \ \ \ \ ] V \ \ \ \\ \ 1 WCold Spring i 1 V\i 1 / W / / \\ / ,/ r \^ V > / f _x y ! ^ ^ 20 40 60 Capacit_y in thousands of acre -feet .. OJ CS ro o ©■"^ 188 DIVISION OF WATER RESOURCES TABLE 48 SESPE CREEK, COMPARATIVE COST OF CONSERVATION BY RESERVOIRS, SPREADING GIVEN PRIORITY Name Approxi- mately most economic capacity, acre-feet Total cost Conserva- tion, acre-feet Cost per acre-foot, conservation Cold Spring... TopaTopa.. .. 40,000 40,000 $1,920,000 6,000,000 8,600 16,400 17,500 18,800 J224 366 Cold Spring . 40,000 20,000 1,920,000 3,860,000 TopaTopa. Combined 60,000 5,780,000 330 Cold Spring 30,000 30,000 1,760,000 4,850,000 TopaTopa... Combined 60,000 6,610,000 352 The cost of conservation and amounts on all different reservoirs and spreading works are brought together for comparison in the fol- lowing table : TABLE 49 COMPARATIVE COSTS OF CONSERVATION Investigated Reservoirs and Spreading Works Name Approxi- mately most economic capacity of reservoir, acre-feet Average annual conserva- tion, 1922-1932 Cost per acre-foot of conser- vation Piru Creek — 11,600 15,000 20,000 30,000 40,000 60,000 •3,000 3,470 4,800 5,770 8,600 17.500 $570 Spring Creek. 455 Blue Point 730 Devil Canyon 625 Sespe Creek — 224 Cold Spring and Topa Topa combined Spreading Works (see Chapter XII) . 330 Piru 4,800 12,600 84 Montalvo 28 * Includes Liebre Creek diversion. Even after allowing for wide variation between estimated conser- vation by spreading and actual performance and adding also a reason- able extra sum per acre-foot for operation and maintenance, two definite conclusions may be drawn from the foregoing: 1. Spreading works are the cheapest items in the construction pro- gram per unit of conservation and Montalvo works should be preferred to Piru works. 2. Cold Spring Reservoir is the most favorable for construction of any surface reservoir and Topa Topa is next. There is another conclusion of importance, but before stating it, reference is made to Chapters VIII and XII wherein water supply of Santa Clara Valley and spreading works are discussed. Analysis indi- VENTURA COUNTY INVESTIGATION 189 cates that tlie total conservation estimated durinj;' dry cycles ior Piru Creek would not drift downstream with suflScient rapidity to become available to Oxnard Plain if the dry cycles of the future are comparable in length to that from 1894 to 1904 or to the present dry cycle if it does not extend many years into the future. It would finally reach Moutalvo Basin but if it did so after the water table had raised due to a wet cycle the need for it would have passed, the basin would be full and the water in question would waste into the ocean. As development goes on and the water table is lowered further in Piru Basin, and to an extent in Fillmore and Santa Paula Basins, more of the water spread in the dry cycles would be intercepted before reaching Oxnard Plain or Saticoy diversion works and the benefit of such works to the areas to the south and to Oxnard Plain would decrease, assuming that Oxnard Plain water table is never pumped so low that there is possibility of sea water encroachment. Estimated conservation by surface reservoirs on Piru Creek shown on Plate XLI is assumed to be done in conjunction with spreading, that is, it is assumed that their water is emptied and caused to perco- late in the Piru spreading works as soon as possible. If this is done, a part at least will never become useful to the lower and southerly areas lor the same reason that the water spread without reservoirs will not. The results of studies made for this report for the 40-year period 1892-1932 indicate that there would be no shortage in Santa Clara Valley for a similar period and that there is no possibility of it unless rainfall becomes much more deficient than that so far recorded. Con- sequently conservation of Piru Creek water, aside from incidental local advantages, would be only for areas elsewhere which are short of water supply. To get full benefit to these areas Piru Creek water conserved in surface reservoirs would have to be transported from Piru Canyon to place of use. Therefore the following additional conclusion may be made : 3. To the foregoing cost estimate of conservation of Piru Creek water the cost of a 25-mile conduit from Piru Canyon mouth to the proposed Saticoy diversion should be added. Without this the esti- mated salvage is larger than the actual amount that will be available to supply shortages. Pumping in Santa Paula Basin The underground storage capacity unoccupied is comparatively small in Santa Clara Valley and Coastal Plain and can not be increased except by more severe drought than has occurred in the period of record or by additional draft to lower the water table. The amount of lowering permissible is limited by possibility of salt water intrusion in the Oxnard Plain and by cost of pumping in Piru Basin so that at best the capacity in these areas to care for possible ultimate development of areas to the south, is insufficient during dry cycles. Additional capacity could be created by pumping Santa Paula Basin if additional w^ater becomes necessary after spreading works are installed. This would lower the water table and increase conservation in two ways : The willows which border the stream would be killed and the water now consumed by them would be available for beneficial use ; 190 DIVISION OF WATER RESOURCES there would be an area provided in the river wash into which addi- tional percolation could take place. If such pumping were done it would be done only for transporta- tion of the water to Oxnard Plain, Pleasant Valley and other areas south of South Mountain. No immediate necessity for this conserva- tion is apparent and it remains a matter for study as time goes on. It involves legal and physical complications but these are not insoluble. The physical cost per acre-foot would be less than could be secured at any surface reservoir available. Such pumping would decrease the salvage of the spreading works below but would increase the total salvage possible in the lower river. Some additional cost would be incurred by pumping the water from Santa Paula Basin which would otherwise have reached the spreading works. Against this those who received this water on the surface would be relieved of present pumping cost and could afford to finance the project to an equal amount. As a basis for estimate of cost the following plan was laid out: A maximum pumping drawdown of 60 feet by a combined plant capacity of 75 second-feet from 30 wells, together with conveyance channel capacity of that amount from the wells to a point about one mile west of Camarillo and thence 25 second-feet capacity to a point along Camarillo Road about 1^ miles east of Calleguas Creek. A diversion canal extending from the Turner Ditch intake on Santa Clara River, about three-fourths mile above Willard Bridge at Santa Paula, with a capacity of 40 second-feet would connect with the river bottom pipe conduit which would collect the water from the pumping units. The estimated cost is $954,000. (See Plate IV.) Reservoir on Conejo Creek A reservoir site on Conejo Creek, about five miles southeast of the town of Somis, was surveyed and found to have a capacity of 8280 acre-feet. The estimated cost is $808,000.* The supply to it from Conejo Creek is negligible and if the site is used, water must be con- veyed to it from Santa Clara River. There are other possible sites in and north of Camarillo Hills and to the east of Somis which have not been surveyed. Conduit from Santa Clara River to the South The reservoir could be utilized for storing water diverted from Santa Clara River during the winter season. It is estimated that a 200 second-foot conduit from the Saticoy diversion operated only during floods when the spreading works could not operate and at other times when water was available in excess of capacity of spreading works would divert an average of 3400 acre-feet per annum from Santa Clara River during the period 1922-1932 but the capacity of 8280 acre-feet would be required to accomplish this conservation. The cost of the con- duit given in detail on page 222 is estimated at $1,300,000. Its location is shown on Plate IV which shows also the location of the reservoir. The conduit would start from the end of the conduit conveying water to the Saticoy spreading works, thence skirt South Mountain through difficult construction between South Mountain and Camarillo Hills, ♦ See page 238 for detail estimate. VENTURA COUNTY INVESTIGATION 191 thence a 2300-foot lined tunnel tliroiioino- estimates are correct unless pumping draft in wet cycles should be smaller than during the investigation, thus allow- ing the basin to fill at such times and decreasing the amount needed in dry cycles. If the situation has been correctly evaluated the next step is dis- tant in the future. No immediate need for additional water appears to exist in Pleasant Valley or any valleys to the south whether they are permanently overdrawn or not. Until the pumping lift becomes considerably greater than present, water can be obtained in such valley's by present practice probably more cheaply than it can be imported from Santa Clara River. When and if the time arrives to conduct water to the south con- sideration should be given to the comparative merits of building sur- face reservoirs to conserve it or creating new underground reservoir capacity in Santa Clara River Valley below the city of Santa Paula. Reference is made to the preceding discussion in this chapter of pumping in Santa Paula Basin. Natural recharge and limited draft in Santa Clara River Valley keeps the water table near the surface along most of river in Ventura County and there are only two areas at present where unoccupied capacity exists and then only during dry periods. These are in Pirn Basin extending down into Fillmore Basin and in Montalvo Basin. Both of these will be fully recharged by the spreading works proposed and even with ultimate development are expected to be full to over- flowing in wet cycles without spreading w'orks. Of all surface reservoirs. Cold Spring on Sespe Creek can be built the cheapest and would conserve 8600 acre-feet at an estimated capital cost of $224 per acre-foot, assuming that Montalvo spreading works are operated as planned. This water would in part percolate as it flowed down Sespe Creek cone but the major part would reach the Saticoy diversion to go southward in a conduit. No attempt has been made to estimate care- fully the cost per acre-foot delivered at the Saticoy diversion from Cold Spring Reservoir as compared to cost of the same delivery of water secured by pumping in Santa Paula Basin but it is believed that if legal difficulties could be equably adjusted the cost of delivering an acre-foot at the diversion by pumping an amount in Santa Paula Basin equal to the possible conservation in Cold Spring Reservoir and thereby creating storage space in Santa Paula Basin, would be prob- ably not more than half the cost of delivering an acre-foot from the surface reservoir. The same pumping installation would make possible the extraction of more water at a smaller unit cost. Further steps therefore depend on the situation as it is at the time necessity exists. Pumping in Santa Paula Basin will be accepted or rejected when the time arrives that more water is needed. Further steps after that development or in lieu of that development depending on the situation at the time appear to be about as follows in order of desirability: (a) Construction of Cold Spring Reservoir; (b) con- struction of Topa Topa Reservoir; (c) spreading of river water in 13—8367—8375 194 DIVISION OP WATER RESOURCES Fillmore Basin if the water table lowers; (d) construction of Camarillo Reservoir or other reservoirs in southern valleys and enlargement of the lower end of the conduit from Santa Clara River; (e) construction of Devil Canyon Reservoir on Piru Creek. THE SILT PROBLEM In attempting to conserve the waste water of Santa Clara River the silt carried by the stream and its tributaries will add to the cost an amount which can not be accurately evaluated and this intangible cost must be considered in any construction program. It is not considered in the foregoing estimates. Surface reservoirs will even- tually be filled with silt, their usefulness gone and the investment destroyed unless they can be desilted. It is believed that the pro- posed spreading works are so designed that the silt can be removed and placed in a position where the normal floods will carry it into the ocean but this will add to the operating cost. Conservation by pump- ing from Santa Paula Basin would not encounter this problem to any greater extent than it occurs naturally. Silt if deposited would be removed without effort. The situation appears to be as follows : 1. Pumping in Santa Paula Basin to create storage space under- ground and kill the willow growth which is now wasting water would not be hampered by an aggravated silt problem. 2. Spreading works which accomplish any considerable amount of salvage must be operated in floods and the silt consequently deposited in them must be removed artificially, thereby increasing operating expense. 3. No way of removing silt from surface reservoirs is known and the usefulness of any constructed must eventually be destroyed unless it can be disposed of. Some are located more favorably than others and other things being equal, if surface reservoirs are constructed the location at which the silt carried is least should be chosen first. CHAPTER XIV VENTURA RIVER BASIN WATER SUPPLY AND DEVELOPMENT Ventura River drains an area of 226 square miles. It discharges into the extreme northerly end of the Coastal Plain and its waters under natural conditions do not influence the supply to the under- ground waters of the plain. The principal tributaries are Coyote Creek from the west, with a drainage area of 41 square miles and San Antonio Creek from the east, with a drainage area of 51 square miles, which enter the river at the upper end of the canyon which the river has cut in the coastal range to find its way to the ocean. These two tributaries extend fan- like from the main stream and their valleys together with the river valley form a basin of plains and rolling hills entirely surrounded by mountains. Rainfall, as shown by Plate II, page 18, averages from 19 inches to 23 inches annually and is higher than in most of the habitable por- tion of Ventura County. This is reflected in the more prolific growth of oaks which cover large portions of the hills and plains of the valley. The eastern arm of the valley drained by San Antonio Creek is known as Ojai Valley from the town of that name. The western end is called Santa Ana Valley from the name of the creek, while the center drained by Ventura River is called Upper Ventura River Valley. The status of lands is shown in Table 71, page 221, and Plate C, in rear pocket. The city of Ventura gets most of its supply by gravity and pump- ing at a diversion point above Casitas Road Bridge. Its production from this source is not known exactly but the entire supply from this and other sources was 3300 acre-feet in the twelve months July, 1932, to June, 1933. From this it supplied inclusive of transportation losses approximately 1400 acre-feet for domestic use in the city, 1400 acre- feet for industrial use, and 500 acre-feet to 777 acres of irrigated land along Ventura Avenue, north of the city limits. Water Supply and Present Demand For the Ventura River Basin all analyses of the water supply have been made for the period spring, 1922, to fall, 1932, as this encom- passes the period of most deficient rainfall on which there are records. The average water crop for the period is estimated to be as follows : TABLE 51 AVERAGE WATER CROP, VENTURA RIVER BASIN, SPRING 1922— FALL 1932 Ventura River System 18,900 ;vcre-fcot Santa Ana Creek System 6,300 acre-feet San Antonio Creek System 4,800 acre-feet Total - 30,000 acre-feet ( 195 ) 196 DIVISION OF WATER RESOURCES Compared to this the estimated use of water is approximate!}' as follows : TABLE 52 USE OF WATER, VENTURA RIVER BASIN Consumptive use — irrigation and domestic, 4,300 acres at 1.00-1.25 4,300-5,400 acre-feet Consumptive use of Willows, etc., immediately above Casitas Road, 150 acres at 4.00 600 acre-feet City of Ventura, approximately 3,000 acre-feet Total 7,900-9,000 acre-feet The remainder of 21,000-22,000 acre-feet wastes into the ocean or is consumed by vegetation below Casitas Road. OJAI BASIN It is in this basin that the development has been most rapid and it is here that it is to be expected to be most rapid for the near future. Practically all water supplies are secured by pumping. Ground- water is replenished from rainfall on the valley floor and by percolation of Gridley, Senor, Horn and miscellaneous smaller creeks as they cross the large and porous detrital cones at their mouths. It is only in years of larger floods that water from these canyons is sufficient to cross the cone and reach the channel of San Antonio Creek. Rainfall on the valley floor averages about 20 inches annually and of this a consider- able portion penetrates to the water table. Development As shown by Table 71 there are 1540 acres net now using water on both hill and valley ; 2470 acres remaining in the valley which can be considered as irrigable judging from the topographic standpoint; and 620 acres classified as "irrigable or habitable" on the hills (Plate XLIX in rear pocket). The future is problematical. In the valley the climate immediately east of and adjacent to the city of Ojai has been found too cold for citrus and little attempt has been made to grow other crops. On the hills the soil is of poorer quality and the future use of the land probably lies in subdivision into estates. The cost of water would not be of moment to such holdings as in general only the area immediate to the dwelling place is irrigated. For the pur- pose of an estimate it is assumed that 75 per cent of the remaining valley or 1900 acres and 25 per cent of the remaining hill land or 150 acres wull demand water at some future day if it is available. This amounts to assuming that all the hill land will be subdivided but only one-quarter actually irrigated. What has been said in a previous chapter in discussing the future of valley lands not now irrigated in Santa Clara River Valley and the difficulty in reclaiming them applies even more cogently to Ojai Valley where return from citriculture is smaller. Underground Basin With information available no attempt has been made to estimate the change in content of the underground basin during the years of investigation. The drop in water table between fall 1927, when the depth to w^ater was first measured, and fall 1931, the lowest level reached during the investigation, averaged 46.8 feet over the area VENTURA COUNTY INVESTIGATION 197 in which wells exist. By fall 1932 the water table had recovered 32.1 feet or 71 per cent. At elevations at and above that midway between the hig-hest and lowest above noted water seeps out of the basin to San Antonio Creek. Period Chaiifje per year Averafje rainfall over basin Per cent of long time average Fall 1927-fall 1931 .___ —11.7 14.81 74 Fall 1931-fall 1932 .___ +32.1 27.34 135 Additional capacity could be secured by pumping below the water table of fall 1931. Water Supply The estimated average annual run-off tributary to Ojai Valley is 5000 acre-feet for the period of deficient rainfall for which calculations are made in this report. No estimate has been made of consumptive use for irrigation or of run-off out of the valley. Average annual rainfall penetration is thought to be above 800 acre-feet. Conclusion It is believed that the average annual recharge of Ojai Basin is greater than present draft on it. The basin is limited in capacity and changes in water table are large during a wet or dry year. It is believed that the same formation found above the lowest recorded water table exists below it and hence that capacity to retain recharge could be increased if the water table lowered and this will come about as development increases. Leakage from the basin would be decreased if the water table lowered. It seems probable that if spreading is done when it eventually becomes necessary the average annual recharge during a period similar to the 40-year period since 1892 would be sufficient to maintain a draft at least 50 per cent greater than present and perhaps more. The additional draft would cause much further lowering of the water table and more extreme annual fluctuations than present. It will be perhaps many years before development will cause draft to approach available natural supply. If it passes it, spreading on the cones should be the first step in conservation and if necessary to import, Ventura River is the possible source. SANTA ANA CREEK VALLEY Only 170 acres are now irrigated and those by gravity. There are no underground reservoirs of sufficient capacity to furnish a supply. As shown by Table 71, page 221, there is an area of 2600 acres in the valley floors classed as irrigable topographically and 1300 acres in the hills classed as "irrigable or habitable" on Plate XLIX in pocket. Perhaps there are small reservoir sites not discovered in this investigation in which a supply can be conserved for summer irrigation, but the amount which can be thus developed is believed negligible. It is not believed feasible to develop any other reservoir sites for irrigation and, therefore, studies have not been made. There appears little possibility of further development of irrigated agriculture but 198 DIVISION OF WATER RESOURCES if demand arises and if Dunshee Reservoir is built a supply might be secured from it. UPPER VENTURA RIVER VALLEY Ventura River after leaving the mountains has cut a channel in the alluvium considerably below the general level and about 2000 feet wide. It continues in this until it reaches the mountains below. For the first six miles the stream loses water. Below this point the river bed is still absorptive but the water table is close to the surface and water rises in the stream bed so that a dense growth of water-loving vegeta- tion is maintained almost to the ocean. The largest single area thus occupied is immediately above Casitas Road where there are about 150 acres of willows. Present irrigated area above Casitas Road draw- ing on Ventura River supply is about 1000 acres in the valley and 40 acres in the hills. Below Casitas Road a total of 1320 acres is using water supplied by the city, of which 780 acres are irrigated land and 540 acres are subdivision. In the A^alley above Casitas Road there are 3800 acres classed as irrigable from a topographic standpoint and 2200 acres in the hills classed as "irrigable or habitable" on Plate XLVIII in rear pocket. Below Casitas Road there are in the river valley proper another 1000 acres classed as irrigable from a topographic standpoint and about 460 acres of hill land classed as "irrigable or habitable." The greater part of the land now irrigated above Casitas Road receives its supply from gravity conduits diverting from the river and taking all the summer flow. Wells have not been successful on the mesa to the east and west of the river wash. Some pumping from the river wash has been done for lands to the west but only small areas are thus irrigated. Apparently no serious attempt has been made to secure water from this source for lands to the east. Percolation in River Wash During the investigation the only period when the flow of the stream continued long enough to get measurements of percolation was in 1932. The estimated average daily discharges and percolation losses are shown in parallel at various locations in Table 7. page 62. There are no wells below Meyer Road by which distance to water table can be determined, but in general it is believed that it is not at great depth. The run-off for the season 1931-1932 was about 12 per cent above the estimated average for the forty-year period. The measurements on percolation above cited indicate that the cone soon fills with an above normal run-off. It is believed that the yield of Ventura River Basin could be increased by pumping from ground water in the basin between Casitas Road and La Crosse and also in the basin above La Crosse. This would increase the yield (1) by depriving the water-loving vegetation of the water which it now transpires and (2) by providing space to impound the floods of the more prolific years of the dry cycles. The only present user which could pump this basin is the city of Ventura. The folloAAing table based on interpolation between occasional measurements shows the approximate discharge of rising water above the city's intake at Casitas Road and above Coyote Creek inflow but VENTURA COUNTY INVESTIGATION 199 below San Antonio Creek compared with the city's use of water July, 1931, to June, 1932, inclusive. As tlie surface flow of both creeks is negligible the quantities in the table are presumed to be rising water mainly from the underground storage basin in Ventura River Valley. The city supplements its supply by pumping in the river gravels near this point. Presumably when this pumping is going on natural rising water is decreased. No attempt is made to evaluate the total possible yield from this basin at present or if supplemented by spreading operations in the basin. TABLE 53 APPROXIMATE AMOUNT OF RISING WATER ABOVE VENTURA CITY INTAKE Based on Occasional Measurements Discharge in second-feet 1928 1929 Demand, second-feet January 1--. February 1. March 1 April 1 Mayl June 1 .lulyl August 1 September 1 October 1... November 1 December 1. 7.5 8.5 9.0 8.0 6.5 5.5 5.0 4.5 4.0 2.5 2.0 1.5 2.0 2.5 7.5 12.0 13.0 11 5 7.0 7.0 5 5 4.5 3.0 3 2.5 4.0 5.5 6.5 7.0 7.0 6.0 7.0 2.0 3.0 1.0 10 1.0 .5 1.0 1.0 2.0 3.0 2.5 2.0 2.0 1.5 1.0 1.0 2.0 5.0 8.0 13.0 13.0 13.0 9.0 8.0 5.0 4.0 3.4 2.9 4.7 4.9 5.2 4.9 6.0 5.9 4.8 5.0 4.1 3.9 POSSIBLE DEVELOPMENT VENTURA RIVER VALLEY The cost of Dunshee Reservoir on Coyote Creek * and Matilija Reservoir on Matilija Creek was estimated for various capacities. These are discussed in Chapter XI and a curve of total cost for various capacities is shown on Plate XXV, page 120. A curve of acre-foot cost of capacity is shown on Plate XXVI, page 122. In estimates of yield it is assumed that Santa Ana Creek is diverted to Dunshee Reservoir through the low pass on the north side by a 200 second-foot canal 1.25 miles long. The estimated cost is $35,000 and this should be added to cost of that reservoir shown on the above plates. TABLE 54 DUNSHEE RESERVOIR Approximate Yield and Cost, 1922-1932; Annual Draft Equal Each Year Capacity, acre-feet Cost* Conservation,* acre-feet Cost per acre-foot of conservation 2,600 5,000 7,400 9,800 $505,000 610,000 780,000 1,010,000 1,000 1,500 2,000 2,500 $505 407 390 405 ' Includes diversion from Santa Ana Creek. * Surveys of Dunshee Reservoir by other interests were available but no sur- veys were available for another site a short distance above the mouth of Coyote Creek. Funds were not available for the survey and no estimates were made of the cost. Its location is not shown on Frontispiece. This site should be investigated if reservoir development is planned. 200 DIVISION OF WATER RESOURCES Curves of estimated yield for dififerent capacities were not drawn but the following tabulation shows approximations derived from various studies of the salvage accomplished by these reservoirs for the period 1922-1932. TABLE 55 MATILIJA RESERVOIR Approximate Yield and Cost, 1922-1932; Annual Draft Equal Each Year Capacity, acre-feet Cost Conservation, acre-feet Cost per acre-foot of conservation 8,100 10,000 14,000 J2,330,000 2,550.000 3,300,000 2,600 5,300 5,800 5533 481 570 The cost of a pipe line to carry 25 second-feet to Ojai Basin was also estimated, based not on a detailed survey but examination of U. S. G. S. topographic sheets and a reconnaissance of the line. This water would be spread when not needed for direct irrigation. This cost esti- mate given in detail on page 226 is $215,000. City of Ventura The city apparently does not have a full supply for present demands at its present intake in Ventura River during the late summer and fall and in dry winters. Although the gravity flow is supple- mented by pumping, supply to the pumps is insufficient. The average annual waste from Ventura River Basin in the dry period 1922-1932 is estimated at 22,000 acre-feet after supplying all demands of the city and in the valley above. Evidently there is plenty of water but the difficulty lies in making it available. The following possibilities for the city should be investigated. 1. Installation of pumps in the valley below Casitas Road or near the ocean or perhaps leasing already existing wells. No investigation Avas made of the ])ossible yield from these sources or the chances of contamination by salt water intrusion from the ocean or from the oil M'ells. 2. Development of the Upper Ventura River Valley underground basin by wells and spreading grounds. This may involve some legal complications and the yield from it is uncertain. 3. Construction of Dunshee Reservoir or other reservoir at con- siderable expense. 4. Pumping in the Coastal Plain northwest of Saticoy and in the area receiving its supply from Santa Clara River. This may entail legal complications. Lands in Upper Ventura River Valley A certain additional development is believed possible by pumping from the gravel basin. The fact that this has not been extensively done although the water is there leads to the belief that cost and other com- plications have impeded it and that returns from agriculture would not justify it. If the surrounding area is subdivided into estates such a tlevelopment would secure water in this waj^ and the cost would not be prohibitive. NFALL ._. — _^ ^ Acton No. 1 Power House"* Snyder Ranch Conejo Ranch No. 1 Santa Susana 1892-93 .-- . 20 53 5 45 13 91 8.44 18 54 1893-94 1894-95 1895-96 1896-97 .. 11.93 1897-98 5-83 4.00 6.50 14.50 10.68 4.26 7.88 7.81 13 09 10.41 1898-99 1899-00 1900-01 1901-02 1902-03 15.74 4.62 17.54 16.04 21 37 17.55 7.82 20.67 18 57 23.02 1903-04 1904-05 1905-06 1906-07 1907-08 11.49 12.11 14.99 12.92 13.80 16.01 23.82 14.97 20.79 9.43 1908-09 .- 1909-10 1910-11 1911-12 ... 1912-13 9.04 17.80 17.62 14.37 10 35 11.14 22.02 16.75 17.08 15 74 1913-14 26 36 22.80 16.63 15 96 19 79 1914-15 19 92 1915-16 16 96 1916-17 11.90 1917-18 9.25 13.12 13 55 11.48 14.74 16 81 10.10 9 43 11 60 15.91 15.99 11.79 11 49 12 10 20 02 17 99 1918-19 14.34 17.92 17.55 26.44 8.11 1919-20 . 10 74 1920-21 7 24 1921-22 16 30 1922-23 1923-24 1924-25 - - 10 55 9.49 7.70 13.18 13.81 16.91 8.06 12.72 21.64 21.66 12.51 6.26 9 28 16.68 15 45 9.50 7 39 9 29 18 75 18 22 8 53 5.36 9.92 1925-26 18.25 1926-27 16.28 1927-28 6.51 7.24 7.78 9.06 16.32 13.52 13 54 12.46 16.99 25.23 9 95 10 46 9.83 10 33 15 87 10 89 10 00 12 02 12 59 i 17 60 12.05 1928-29 10.34 1929-30... 11 16 1930-31... 11 to 1931-32 15 91 Years of record. 36 14 40 19 19 11 86 17.07 13.65 14 70 13.09 11.66 17.64 13.65 14 88 13.25 3,300 3,000 300 650 980 1 38 54 5 50 ' • Records from Los .\ngeles County Flood ( •• Records from United States Weather Bur *** Los Angeles City Water Works Departmt 836^ -8375 — pages 200-201 TABLE 56 RECORDS OF PRECIPITATION AT KEY STATIONS USED IN COMPUTING AVERAGE ANNUAL RAINFALL Seasonal Year, July 1-June 30. Rainfall in Inches Santa Barbara** •Ojai Valley** Valley Matilija Canyon Wheeler Springs Mono Ranch'* Hueneme Santa Paula Fillmore Newhall Ranch Mellon Ranch* Newhall Depot" Acton No. 1 Power House*** Snyder Ranch Conejo Ranch No. 1 Santa Susana 26.97 7.02 16 34 13.37 18.50 19 62 6.28 13.13 10.27 10.37 23,14 7.19 19.86 8.76 18.42 20.53 545 13 91 8.44 18 54 12.68 11.93 4.99 1233 12.66 16 40 14 21 3.03 10.77 9.56 10.55 11.68 5.91 7.40 9.57 16.09 13.09 2.73 2.98 6.46 9.28 6 34 5.62 5.44 7.59 19.08 9.89 5.83 4 00 6 50 14.50 10.68 4.26 7.88 7.81 13.09 10.41 lUOO-01 25.64 16 03 1901-02. 19.38 1902-03 _ 20 74 11.58 29.64 22.70 27.72 22 65 12 54 37.32 25 53 42 38 23 64 14.78 45.20 38 99 53,36 18.62 7.39 19,17 16,27 23,92 18.40 11.54 24.26 17.93 27.83 12 35 3,80 13 31 12 37 15 97 19 64 8 22. 27.53 18 39 33.06 15.74 4.62 17,54 16,04 21 37 17 55 7.82 20.67 18 57 23 02 1903-04 17.75 40.75 26 87 41 00 1904-06 1905-06 23.71 37 44 19 81 27,52 1906-07. 1907-08 19.21 36.29 19 62 31 94 16 35 18 95 29 24 19.64 33.91 13 34 21.17 33 70 16 32 33 01 20 25 35 55 30 86 45.48 27,18 40.80 24.38 55.82 20.02 15 11 19 93 13,17 17,83 9,51 14.58 25.90 13 94 22.00 11 14 15 55 26 45 17 48 25,25 12 12 1,09 8,08 9,66 10,48 7,65 15 31 22.63 19.85 22.72 20.03 11,49 12.11 14.99 12.92 13 80 16.01 23.82 14.97 20.79 9 43 1908-09 . 1909-10 1910-11. 1911-12 1912-13 12 58 31.52 21 25 25.90 22.56 18 12 39,60 24 02 28 30 22.15 19 71 46 26 27 03 26 23 19 36 19 00 50 75 27 60 33 87 25 27 22 92 58.72 11,62 17,95 18,52 17 53 17,08 14,91 28 98 23,12 23 05 21,39 16,15 32 99 23,13 24,99 21,12 13.78 5,09 14,09 12 65 10,49 5 95 17.79 31 24 27.50 9.04 17.80 17.62 14 37 10 35 11.14 22.02 16 75 17.08 15.74 1913-14.. 26.36 22 80 16 63 15.96 19,79 1914-15 19.96 20.50 12.49 19.92 1915-16 16 96 1916-17 11.90 1917-18 21.68 14 46 14.68 14 31 19 22 24 99 13.55 16.64 18.30 26 91 29 05 14 62 16 22 17.98 29 56 28.00 16,98 9,67 8 30 11,42 14 81 19,84 12 41 14 24 17,28 21 10 19,94 11 33 15 17 18,72 22 81 18 06 12.10 14 02 14.06 21 31 8,20 8,61 9 84 8 89 14 49 9.25 13.12 13.56 11.48 14.74 16 81 10.10 9 43 11.60 15 91 15.99 11.79 11 49 12 10 20.02 17 99 1818-19 11.31 14.51 21.71 31.15 14.34 17.92 17.55 26.44 8 11 1919-20... 16.88 17.37 33 25 10 74 1920-21.. 1921-22. 16 30 1922-23. 17 24 6 36 12 26 16 87 22 68 18 83 7.30 11 96 21 70 26.19 17 05 7 13 11.36 19 71 26 31 21 77 9 49 12 67 32 04 33 07 10 24 5.78 8.04 15 24 16.68 14 93 7,71 10,01 16 41 23,32 16.53 7.28 10.52 20 34 23.24 13 23 7,99 8 47 18,78 17 57 6 68 6 26 7 64 11 01 11,89 11.22 8.01 7.49 25.53 23.66 10.56 9 49 7.70 13 18 13,81 16.91 8 06 12 72 21 64 21 66 12.51 6.26 28 16 68 15 45 9.50 7 39 9,29 18,75 18,22 1923-24... 1924-25. 14 34 38.20 9.92 18 25 16.28 1025-26. 1926-27 1927-28 13.54 14.54 13.71 14.55 22,13 15.66 13 14 13.99 16.62 26 11 13 31 14 29 15 45 16 63 28 83 14.74 19 28 16 76 16 94 30.05 17.80 20 03 18.31 17.91 30.96 9.07 9.18 10 03 11.31 16 05 11 15 13,48 12,26 14.00 20.60 11 35 16.10 14 57 14.69 23 19 9,80 12 24 14 60 12,89 21,37 4,80 5 98 9,86 10 26 15,58 10.46 12.70 11.10 14.07 2S.47 6,51 7,24 7,78 9,06 16,32 13 52 13 54 12.46 16 99 26 23 9 95 10 46 9.83 10 33 16 87 10,89 10 00 12 02 12,59 17 60 12.05 10.34 11.16 11 £0 15 91 1928-29 1929-30.... 1930-31 1931-32 36.11 Years of record 65 27 31 27 7 14 40 35 27 19 36 37 36 14 40 19 19 Mean of re?ord. 18.10 21 49 22.66 26 56 22 51 34 38 13 31 16 56 18 83 14 91 9 18 17.23 11 86 17 07 13.65 14 70 13 00 ■ Estimated 40-year mean 18.24 20.14 21.06 24.48 27.30 28.11 13.31 16.56 17.94 15,59 9,02 17.28 11.66 17.64 13.65 14 88 13.25 Elevation above sea level 125 800 1,250 950 1,560 3,210 10 275 530 750 3,100 1,273 3,300 3,000 300 650 980 Station number. 46 30 64 107 70 21 17 48 11 25 74 28 1 38 54 = 30 • Records from Los Angeles County Flood Control District. Records from United States Weather Bureau Los Angeles City Water Works Department -8375 — pages 200-201 TABLE 57 SUMMARY OF DETAIL CALCULATIONS OF RAI^fFALL PENETRATION IN INCHES' Seasonal rainfall Penetration below root zone Citrus Deciduous Bea.is Grain Truck, miscel- laneous, garden, alfalfa Bare land Grass and weeds Basin Clean cultivated Cover cropped Clean cultivated Cover cropped Irrigated Non- irrigated Fall planted Irrigated Irrigated Brush Clean cultivated after crop Planted to truck after crop, also beets alone Clean cultivated after crop Irrigated Non- irrigated Just prior to rains Usual practice Just prior to rains Usual practice FOR 1927-28 Piru Fillmore -- Santa Paula -- - -- Montalvo, north of river''- - - Montalvo, south of river ''_ West Las Posas, - _ 10 44 11 57 9,71 9 92 9 SB 9 90 9 98 10 03 ^■10,95 11,93 J14 36 14 36 13 09 11 97 15 42 12 72 11 06 10 69 12 27 10,34 10 39 '11 09 11 84 12,97 14 72 12 28 1 4 !l 7 9 1 1 1 1 6 1 5 8 1 1 3 1 3 1 2 3 1 8 3 9 1.2 2 03 3 4 1 7 11 1 7 3 5 2 2 1 1 1 1 5 1 9 1 1 5 7 1 4 9 7 9 1 1 1 1 6 1 5 8 1 1 1 6 1 6 1 6 1 5 2 1 2 2 2 1 7 7 13 1 8 1 2 1 2 3 8 6 1 9 2 1 3 10 6 6 2 7 1 3 2 5 4 8 4 8 2 9 3 6 9 3.3 2 1 7 1 7 1 5 1 9 2.2 2 9 3 6 5 6 3 3 1 8 1 8 1 3 1 9 1 1 1 1 9 9 2 2 5 2 8 2 8 9 13 3 9 1 3 1 1 1 12 1 6 3 5 13 2 3 3 3 2 8 2 8 2 13 2 9 1,2 1 1 1 5 1,1 1 1 2 9 19 6 0,6 3 1 4 U 10 5 2 9 3,0 2,3 2 1 5 15 1,1 1,7 2 3 3 5 5 8 5 8 3 9 4 6-9 4 3 3 2 7 2 7 2.5 2 9 3 2 3 9 4 6 6 5 4 3 n Simi _ OjaiValley..- __ Ventura River Ventura Avenue . _ _ FOR 1928-29 Piru Montalvo, south of river'', . West Las Posas - . - Pleasant Valley'- Lag Posas (Moorpark) Simi Ojai Valley. Ventura Avenue 8367— 8375— pages 200-201 FOR 192S-30 Km..- Fillmore Santa Paula MoDtalvo, north of river** Mootalvo, south of river** West Las Posas Pleasant Valley •> Las Posas (Moorpark) , Conejo (Santa Rosa) . _ Simi Ojai Valley Ventura River Ventura Avenue FOR 1930-31 Piru FUhnore Santa Paula Montalvo, north of river *> Montalvo, south of river** West Laa Posas. Pleasant Valley** Las Posas (Moorpark) C!onejo (Santa Rosa) Simi Ojai Valley Ventura River Ventura Avenue FOR 1931-32 Piru Fillmore Santa Paula Montalvo, north of river*" Montalvo. south of river** West Las Posas Pleasant Valley** Las Posas (Moorpark) Conejo (Santa Rosa) Simi Ojai Valley" Ventura River «... Ventura Avenue 13 58 13.68 II 32 10.97 10 44 11 33 9.87 11 31 13.43 12 94 15 05 13.54 13 23 11.46 11 05 9 86 10.46 12.24 12.35 15 63 15.70 14 23 20 95 21.71 18.68 16.86 15 86 15.82 14 78 15 80 13.54 16.78 26.81 26.29 TABLE 57— Continued SUMMARY OF DETAIL CALCULATIONS OF RAINFALL PENETRATION IN INCHES" Penetration below root zone 9 4 5 S 3 9 Clean Itivated after crop 4 1 4 9 3 2 7 2 2 2 8 1.4 2 1 4 2 5 3 8 2 9 3 8 5 6 3.8 3 2 2.1 16 10 19 2.6 3 3 5.1 5 3 4 9 8 10 7 8 4 6 7 5 9 5 5 5 5 2 3 9 5 6 13 5 15 4 U 9 Planted to truck after crop, also beets alone Clean cultivated after crop 14 5 16 4 12 9 3 this chapter and other information . * Computed by the DiviBion of Water Resources from data '• In non-pressure area. ■^ An average of Pleasant Valley and Simi. '^ No record — used Ojai values. • These figures do not allow for run-off from rainfall, which is estimated to be 1.4 inches for Ojai Valley and 1.6 inches for Ventura River. Estimate based on run-off records. 8367—8375 — pages 200-201 VENTURA COUNTY INVESTIGATION 201 TABLE 58 SANTA CLARA RIVER— ESTIMATED RAINFALL PENETRATION IN ACRE-FEET OF SANTA CLARA RIVER VALLEY AREA AND NON-PRESSURE AREA, OXNARD PLAIN For 40-year Period, 1892-93 to 1931-32 Season Piru Basin Fillmore Basin Santa Paula Basin Montalvo Basin West Las Posas Basin Summation South North 1892-93 10,000 200 3.200 1,300 6,600 18,500 100 6,000 1.500 11.500 10,300 100 3,500 900 6,500 7,100 2,200 500 4,600 3.800 900 200 2.000 4,600 1,500 300 2,700 54.300 400 17,300 4,700 33,900 893-94 1894-95 1895-96 1896-97-.. 1897-98 800 800 2,400 2.000 100 700 800 3.500 2.800 400 500 1,900 1,500 200 200 1,300 1,000 100 500 400 100 900 700 100 2,100 2,500 10,500 8,400 1898-99 1899-00 1900-01 1901-02 1902-03 -. - 5.800 1,000 9,400 5,600 11,300 10.200 1.000 17.100 9.600 21.200 5,600 500 9.600 5,500 11,800 4.000 300 6,500 3,800 8.000 1.700 100 3,400 1,600 4,500 2,500 100 4,300 2,400 5,400 29,800 3,000 50,300 28,500 62,200 1903-04 -. 1904-05- 19D5-06 1906-07 1907-08 3,500 11.200 3,000 9.200 1.300 5.800 21,000 4,700 16,900 1,500 3.200 11.800 2.600 9,500 900 2.100 7,900 1,800 6,400 500 800 4,400 700 3,300 200 1,400 5,300 1,200 4,200 300 16,800 61,600 14,000 49,500 4,700 1908-09 1909-10 1910-U. 1911-12 1912-13 2,600 10,600 7.400 7.300 5,100 3.600 20,100 13,000 12,700 8,700 2,000 11,300 7,400 7,200 4,900 1,400 7,500 5,200 5.100 3,400 600 4,200 2,400 2,400 1,400 1,000 5,100 3,300 3,200 2.200 11,200 58,800 38,700 37,900 25,700 1913 14 1914-15 1915-16 . - 1916-17 1917-18 5,300 1,200 1,600 2,600 6.000 9,300 1,400 2,000 3,800 10,300 5,200 900 1,100 2.200 5.800 3,600 500 700 1,400 4,100 1,500 200 300 600 1,800 2.300 300 400 1,000 2.600 27.200 4,500 6,100 11,600 30,600 1918-19. _-, 1919-20 - - 1920-21 1921-22... 1922-23 2,000 100 800 4,500 6,300 3.000 200 900 8,400 11, poo 1,300 100 400 3,600 6,100 1.000 200 2.900 4,300 400 100 1,200 1,900 700 200 2.000 2.800 8,400 400 2.600 22,600 32,400 1923-24 1924-25 - 1925-26 1926-27 1927-28 900 1,200 1,800 1,700 5,100 900 2,700 2,600 3,000 8,300 300 700 1,000 1,000 4,800 300 700 900 800 3.300 200 300 500 500 1,700 100 400 600 500 1,900 2,700 6,000 7,400 7,500 25,100 1928-29. 1929-30 1930-31 1931-32 202 DIVISION OF WATER RESOURCES ^ - "^ £ o- CO - . Di Ui b o > 2 1 a: 3 S < H - u , a. < > a H a: ^ ta 0) O (/J « t. U ii 3-0 g'm a c g c3 a 3 a,-^ f-.S o o o o ^HOO-^ ^H o o o oo ^ C50 o o oo CO ^H CO o COC^ t^CX) *o o o o o c> ooooo ooooo ooooo ooooo ^ o ? ■^3 a ooooo ooooo ^ ^ C5 occ ooooo ooooo ooooo ^ ^ C ooooo ooooo ooooo ooooo o o o - CC i-H '-" ■O O OCD O <=5 CD o oo ooooo Oi <£> CC Ol o o o-c-o oi o> o oo ooooo ooooo 0> CO CO -^ t- »0 C^'C^CO CO f' CO^ -Tf c> o oo o ooooo ^^o_co^0^t^ »C (m"»-h ^CO — I lO ooooo ooooo to m lO CO lo t-- CO OS OS t>- o oo oo ooooo ooooo 0(000 o ooooo ooooo ^ t^(MC^ rH ooooo ooooo Oiifim t>- CO o o o o o o o o o o ooooo OOi o o o 05 t— -^ O 00 ^oococo^ ooooo I ooooo CD OO) O O owf-^* i-HcoeDt^O -"I^COCOOM OOOOO OOOOO) o o o o ooooo ooooo ooooo ooooo o> o o o o O O'O o o ooooo oo o o- o ooooo ooooo ooooo ooooo ^ ic cocoes o o> o o o- ooooo ooooo ooooo ooooo ooooo ooooo ooooo ^ (M CO O-^ ooooo Oi o o o . C<1 ooooo ooooo ooooo ooooo ^ CO -"-"CO i-x ooooo ooooo ^iC (M (M ^H ooooo ooooo CD ^ CO O lO ooooo ooooo lO oo O CO lO CD r^ CO-' ooooo OOOOO t- oo o o ooooo ooooo ooooo c<) 00 oo —I 00 ooooo ooooo ooooo 000C)0 ooooo 0)0000 C^J T-i CO C-l ^ ooooo ooooo ooooo Ooooo ooooo Tfi ic or- CO ooooo ooooo ^ OiCC^' ooooo- oo OSO •-•(N p O^ ^ w 30 Ol O '-' oo 0*-i — CO Tf w5 cor* VENTURA COUNTY INVESTIGATION 203 o o o oo O O O O C5 I »0 O «0 CO OOOOO I ooooo ooooo ooooo ooooo ooooo ooooo O O OrOO ooooo O O C^0>0 (M CM ^ ^^ C ooooo ooooo o oo- o o ooooo ooooo CO CC CO CO -^ ooooo ooooo ooooo ooooo ooooo t^^CC C» GO ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo |C rr :o —•" O O O O C5 O ooooo OOOOO ooooo OOOOO »0 C^r C^ O 00 ooooo OOOOO c:^ --JT lo c^ c^ "rf'-^'rr"*:}^ oo ooooo ooooo r- :0 t* O "5 ooooo ooooo ooooo — GO ro o c ooooo i ooooo ooooo I ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ^H r-11-.^H oo ooooo ooooo ooooo ooooo ooooo ooooo 00 OCICC '-H — ^o ci_^ o^ O* ic ci" »r3 cc GO — ^r- (M oo o o : 00 cc cc -^'c ooooo ooooo - - - o o t^o_ ■o c; ci c— ' X 204 DIVISION OP WATER RESOURCES TABLE 60 PIRU CREEK Estimated Run-off at Proposed Reservoir Sites in Acre-feet; 40-year Period, 1892-93 to 1931-32 Year Los Alamos Reservoir drainage area, 269 square miles Spring Creeli Reservoir drainage area, 302 square miles Blue Point Reservoir drainage area, 367 square miles Devil Canyon Reservoir drainage area, 389 square miles Piru Creek Gaging Station near mouth ■ drainage area, 432 square miles 1892-93 47,600 900 13,300 7,600 18,000 59,500 1,200 16,700 9,500 22,600 96,300 1,900 27,000 15,400 36,500 103,200 2,100 28,900 16,500 39,200 115,000 1893-94 1894-95 -- - 2,300 32,300 1895-96 18,400 1896-97 43,700 1897-98 500 1,900 3,000 9,000 3,800 700 2,400 3,700 11,300 4,700 1,100 3,800 6,000 18,300 7,700 1,200 4,100 6,400 19,600 8,200 1,300 1898-99 - ------- 4,600 1899-00 ---- 1900-01 7,200 21,900 1901-02 9,200 1902-03 1903-04 - - - - - 12,400 3,100 72,400 20,900 69,800 15,500 3,900 90,600 26,200 87,300 25,100 6,400 146,500 42,300 141,200 26,900 6,800 157,000 45,300 151,300 30,000 7,600 1904-05-. 1905-06 1906-07 175.000 50,600 169,000 1907-08 1908-09 - - 11,400 73,700 13,800 102,300 11,800 14,300 92,300 17,300 128,100 14,700 23,200 149,200 27,900 207,100 23,800 24,800 159,900 29,900 221,900 25,500 27,700 178,000 1909-10 1910-11 33,400 248,000 1911-12 28,500 1912-13 1913-14 1914-15 19,400 103,700 23,800 31,600 13,200 24,300 129,900 29,800 39,500 16,500 39,400 210,000 48,200 63,900 26,700 42,200 225,100 51,600 68,400 28,600 47,100 251,000 57,600 1915-16 76,400 1916-17 --- --- 31,900 1917-18 - . - 33,100 6,200 8,000 6,400 51,000 41,400 7,700 10,000 8.000 63,800 67,000 12,500 16,100 12,900 103,200 71,800 13,400 17,300 13,800 110,600 80,100 1918-19 --- 15,000 1919-20 19,900 1920-21 15,400 1921-22 - 123,000 1922-23 7,600 1,400 1,600 18,500 17,600 9,500 1,800 2,000 23,200 22,000 15,400 2,800 3,200 37,500 35,600 16,500 3,000 3,400 40,200 38,200 18,400 1923-24 3,400 1924-25 3,800 1925-26 44,900 1926-27 - - - 42,600 1927-28 4,500 4,100 3,900 5,200 21,900 5,600 5,100 4,900 6,600 27,400 9,000 8,300 7,900 10,600 44,300 9,700 8,900 8,500 11,400 47,500 10,800 1928-29 - - - - 9,910 1929-30-.-- 1930-31 - 9,440 12,700 1931-32 53,000 Mean 22,000 27,500 44,500 47,720 53,200 Estimated from ratio of area of each watershed and rainfall on each watershed, to area and rainfall of total water- shed and run-off from total watershed at Piru Gaging Station. VENTURA COTTNTY IXVESTIGATION 205 TABLE 61 SESPE CREEK Estimated Run-off at Proposed Reservoir Sites in Acre-feet; 40-year Period, 1892-93 to 1931-32 Year Cold Springs Reservoir drainage area, 65 square miles Topa Topa Reservoir drainage area, 165 square miles Sespe Creek Gaging Station, near mouth 257 square miles 1892-93 56,100 2,600 20,100 10,000 27,500 135,800 6,200 48,500 24,300 66,600 207,000 1893-94 9,500 1894-95 --- 74,000 1895-96 37,000 1896-97 101,500 1897-98 800 3,100 4,500 12,400 5,400 1,800 7,600 10,800 30,100 13,200 2,800 1898-99 11,600 1899-00 16,500 1900-01 45,900 1901-02 20,100 1902-03 . 18,100 4,700 73,400 31,500 71,700 43,700 11,300 177,600 76,400 173,500 66,600 1903-04 17,200 1904-05 1905-06 270,700 116,400 1906-07 264,500 1907-08 17,500 74,300 20,800 92,700 13,800 42,300 179,800 50,400 224.300 33,400 64,500 1908-09 274,100 1909-10 1910-11 76,800 342,000 1911-12 50,900 1912-13 24,500 93,800 34,900 40,500 16,500 59,200 227,000 84,500 98,100 39,800 90,300 1913-14 346,000 1914-15 128,800 1915-16 149,600 1916-17 60,700 1917-18 1918-19 1919-20 .- . 42,400 8,300 9,800 7,800 65,500 102,700 20,200 23,700 18,900 158,500 156,600 30,800 36,200 1920-21 1921-22 28,800 241,600 i 1922-23 9,300 1,500 1,800 23,600 27,500 22,600 3,700 4,400 57,100 66,600 34,400 : 1923-24 1924-25. 1925-26 5,700 6,700 87,100 1926-27-. 101,500 1927-28 5,300 5,100 4,900 4,600 22,500 12,800 12,400 11,800 11,100 54,500 19,500 1928-29. 1929-30 18,900 18,000 1930-31 1931-32 16,900 83,000 M«an 25,300 61,200 93,300 Estimated from ratio of area of each watershed and rainfall on each watershed, to area and rainfall of total watershed and run-off from total watershed at Sespe Creek Gaging Station. 206 DIVISION OF WATER RESOURCES < H O H < z o <; u w b o H a z w u .J < W o b 'o O I u § I >- a z •£ O -o 2 ^ M'W ?o t^eo C^ 05^ 00'**' 0»^COC4C4 ^^oot^ C^ ^H ■^ CO CO . toQOoo^Hwa CO CO CO CO N CO COfMC^-^ (N C^ tOQOO b-cococoTj« c^ CO I-- CO r~-» 00 CO -^'^ CO CO'^COOOO locoeooco OJ ^« CO t^ oo O r^ CO w :o ^ ^ lO » lO c^ <-« -H CO :0 CSJ 05 •— < !>■ OS CO t^ CO T^ - -^ ^^ CO iO CO '— ' CO O:>00«OiOt^ I>-C^ -^O CO oooo^;^ OSOaOOO t-- OO CSO -- O: C: C3 O O OO OO QO OiCi CO ^-^ CO ^ CO CO 04 C4 00 CO r^ i— > CO C4 NC0»-^C4 0J o o o oo ■^coioeo^^ — 'coiccoeo C^ «-« CD —« C^l CD ^^ OC0 00 04 00 OCO*4- VENTURA COUNTY INVESTIGATION 207 oousQO'^eo OS 03 00 ^»0 CO ift m csco r- :Doooo»o osr^io -^lO 1-1 00 C^ CO 00 OQOOSQOO OiSS-^OO 'OOOOMCO CO U5 00 C^l ^ O C^ lO ^ lO — C^ Tr 00 — 00 ^ -Tr »o o oi ooooo ooooo ooooo OS 00 •* C<1 ^^ ooooo ooooo OS .-lOiO CKI — — -^ ^'CO ooooo o>o ooo ooooo lO O O OiO ooooo OOOO'fl" O OS t^ i-" »0 (M rt rt« OOOOO OOOOO OOOOO OOOOO OS ^-H kO O lO ooooo "50000 CO CO -^r 00 CO ooooo lo o oo o ooooo oooooo so If5 oo ooooo ooooo CO CD C^ 00 OS CO — — 00 t ooooo ooooo CO CO CO CO »o c4" C-f ^ CO ic ooooo ooooo — CO t^ C-l (M ooooo ooooo oo O O OS 00 C^l lO CO -^ ooooo oomoo CO — C- ^« lO --0 CO ooooo ooooo C3 00 OO OQ 0% ooooo ooooo SOOOO OXiTftMO 0500050 C^000505 ooi-t-oooo ooor-ocoo I cooosoooo ooooo 5iOO - oo t>- lOOOiOO OOC^OO [Ot^OO^iO OO-^O" ~ t^OO ' OOOI OOOOO OO >ooo OOOOO oooo< ooooo »0 lO o o o '-" — CSICC(M ooooo I ooooo OtOO"D^ ~ ooooo OOOOO ooooo OtOtOOC^ '^f OO *- lO c O »0 O TT ■-' ^^c^^ec «-hc^<: ooooo O OO O 00 o ooooo ooooo ooooo Or^iOOO ooooo I — I O — « CM : 00 to lO C5 " CQ t^ '-' ^ ■^ ^ C I ooooo OiCOOO ooooo I OOOOO o to o oco O O '^f' CM o ooooo 0*0 OO o '-"-H'^CMiO ooooo I OOOOO OOOOO'— lO^OTrosco C5 'S* CO CC-^ I O lO t-^ -^ iO ooooo OOiOOO ooooo ooooo OOOOO O OOtO o OOOOO OO ■<*' ^ ^ O OOOOO O "5 O O O — o o — — ooooo looooo "Oroooos-rt* CM rco — O ooa»o i-«c4 I I 1 I I r-ooo50 •-« ^ « — C^l CM CMCMCMMCM I I I 1 I CI CC ^ lO :C CM CM C) CM CM C5 05 05 02 05 OO 050— ' CM 14 — 8367 — S375 210 DIVISION OF WATEK KESOUKCES Q Z < u Ui u D o h u u b I Zg " a« £!: a z s. sssss ■^ CO '-H'^ sssss (M rt i— (M J »^ <>) ^ CO Soooo oooo W5 i-HiiO (M lO ^ TT OiC^ Oi CO ^ ^ OOOOO §ooo< oooc ■^ CO CO toe Ol CM M 3QOOC >ooo< CO -^ »C I© h» I I I I I (M CO ^ lo OO 00 GO OO OO SSSSS cocoes OSM OOOOO 'SSS 'Siii I sssss O t^ ^O O OS s°sss s^sss SSSSS w ^ M" oos °ssss ssss§ i-H M CO 1— lO '-« lO ^ c 5SS? '-' (M t^ r-co OOOOO OOOOO Soooo OOOO ^ - ooooo o oooo ooo o o C*5 ^H CC' oo o o o o o o o o r--^-^occ o S8SSS 88Si gggsg (M — -^ COCC iO -H — :o iO o oooo o o ooo oo o o o o ooo o i:^^ i-^ 00 M -^r M t^ -^ oo»o »0 C^ « CQ t>» (M 35 00 oo O ^ J O CO O o o o oo JOOOO 1 oooc ■tT! c0 OOOOO OOOOiO I^CO ^00 c^ ooooo c^^ o w3 o o ^H r^ U5 05 CO ooooo ooooo ooooo ooooo ooooo ooooo ooooo O^O C^(M ooooo ooooo ooooo ooooo ooooo t^OOOsO ^ C^ O^ 03 o o QO 00 00 C^ C^ CO ^t* W3 CD t>- Oi OS O) OS VENTURA COUNTY INVESTIGATION 213 cs'^ooSoo ccooust^-^ Ocx>cc^^r>- car^c^ior^ c^-^«coc^ aosacsccoa — ' -V 1 ^ « "3 OOOOO ooooo ooooo ooooo ooooo ' ooooo ^^ CO ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo OOOS'^O 00-^*0'^ — Ci 'o CO cq cq -^ §000 000 oooo OCO CO 05-^ i^ CO 2 ^ OOOOO ooooo OOOOO ooooo »o IC O "5 o ooooo ooooo O^C> C5 OCO o' CO — r-^ CD --< CO 00 C<1 ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo ooooo o o 00 »o 000 o »o ooooo ooooo ooooo oooo-^ CO 00 -^ ^- CI ooooo ooooo ooooo O OOUO iO ■* 50000 OOOOO oooo ooooo OOOcB — lOOOOO U5 O 000 g§ss ooooo ooooo OOOOCO OOOOIM COOOOO •«^»a CO tr^ coco loV"© ooooo ooooo ooooo '88 CS ^« >— t SSSS8 oi -^ iO iri" so 88888 OO ^9* to ^ CO OO — CC CO C^I>-OS I oooo o 8888? U5 ^Ci o )QOOO 50000 1 to U50 O to lO ^ CO i 00C500 I-- c^ lOO o :oco" od — 88888 coc^^oo w to * ^ Vio 888S§ ca O CO ^ C 88888 OOM- C^ M Cq OOO CaO 1-H ^ (M 88888 S*='='8 SS = SS -loqc^»Oco;t^ tolOco 00 OOOOO ooooo eo^j* *o o t^ 0% Cd Ca 03 03 a>oooo QOOiO^CJ 03 c) cd o oa > C3 . C3 K = »> » == fi " =s -Is m ° S ¥ ^ c fe S . o " o^ 2 3 ® oja a, to O 3 3 »— _ « M t?i: 2 2 i I. a -5-5^ "2-^Z £■« » 5 2 D i M S °s -^ a, c= c -I- » -13 si--r^ ja f * |£i2 3 a= M »- oA " •I i I i i O O - 3-^ .S— , >,.2 « op I. 3 * 216 DIVISION OF WATER RESOURCES ooooo ooooo CO r-^ OCOOO ooooo o oo^o '-^CO '-"CO^H ooooo ooooo »--i^ . ooooo ooooo ooooo ooooo ooooo ooooo 1^ c^ r- 00 l~* c-f ococ4"^ ooooo ooooo ooooo o<^ooo ooooo ooooo ooooo o oo^ o ooooo ooooo 05*0 C^ OOO to -^ CD CO -^ ooooo OOOOO ooooo OOOOO ooooo OOOOO ooooo I -^OOOO c^oooo OO CO 00 "^ CQ ooooo ooooo C oooo oooo oo OiOiOS^ o 00 oo oo 05 05 CO Tt« lO CD t-- ooocpo C^ CO -4< «0 CD ooooo oo 050'-H C-1 ??77V 000'-<— < 05 CJl Oi Oi Oi Od O^ O^ Oi o;> VENTURA COUNTY INVESTIGATION 217 SSSSS IgSSSS ^^0*0 05 OOCOC30t>-0 OOQkO ODO CO CO CO CO o CO *0 Tf lO lO ooooo o ooo CO — -^ c^ ooooo 05 00^ '-*-^ »o ^*< CO h-*o ooooo ooooo Ud CS ^ lO m ooooo ooooo ooooo ooooo OSO COtM o M OOiO t— O ooooo ooooo CS COtM-^CO ooooo ooooo M as-**- o oo ooooo ooooo CO '-' r^ eo O ooooo i ooooo ooooo ooooo 00 TT (M -^f lO OiO O OSO ■^ r— oo c^ 00 O ^ C o -^ -* ^ -^ c^ c^ O^ CS C^ OS OS 00O5O -^c^ CI « CO CO CO c^ c^ c^ c*5e^ Cd C& C^ C3 o^ _ 3 03 O c O eO O o 5£^- O K C is " 02 = 3 S la *m-^ ■g'e oa > £ g 4) a IB » a = o i-Hii 218 DIVISION OF WATER RESOURCES TABLE 68 ESTIMATED ANNUAL WATER CROP OF VENTURA RIVER WATERSHED ABOVE DIVERSION DAM OF VENTURA CITY AT MOUTH OF COYOTE CREEK,1917-18 to 1931-32 Acre-feet Season Ventura River area Coyote Creek Matilija Creek North Fork Matilija San Antonio Creek Total 1917-18 24,800 1,100 4,500 4,200 21,400 5,900 700 350 11,200 12,400 600 900 •1,200 •400 •13,200 29,800 1,500 5.700 4,300 32,000 8,300 1,200 500 15,900 17,100 •808 •1,430 •1,720 •563 •15,100 37,300 7,500 8,600 6,800 52,800 14,500 3,000 1,600 20,700 27,900 •5,380 •3,650 •3,630 •1,950 •25,540 12,300 2,700 2,800 2,300 17,400 4,800 1,000 530 6,800 8.600 1,610 •1,270 •1,160 •698 •7,380 14,600 1,700 3,000 3,700 13,200 3,800 170 1,100 6,900 13,200 •1,700 •2,300 •1,600 •2,700 •14,900 118,800 1918-19 1919-20 1920-21 1921-22 14,500 24,600 21,300 136,800 1922-23. 37,300 1923-24 1924-25 6,070 4,080 1925-26 1926-27 61,500 79,200 1927-28 1928-29 10,100 9,550 1929-30 1930-31 1931-32 9,300 6,310 76,100 Average -. _. 41,000 •Measured. All others estimated from rainfall and relative area of watershed. TABLE 1-A ESTIMATES OF IRRIGABLE LAND In Division of "Water Resources Bulletin No. 43, South Coastal Basin Investi- gation "Value and Cost of Water for Irrigation in Coastal Plain of Southern California," by Prank Adams and Martin R. Huberty, authorities of the University of California on irrigation economics, is given an estimate of the additional irrigable land in Ventura County with the exception of Ventura River Basin. The authors do not consider any additional hill land "irrigable according to conservative standards" except in the vicinity of Moorpark. The following table is condensed from Table 49 on page 112 of Bulletin 43 : Es J 3 C! CQ "^ M < u ^ -J H •Z « o g a 3 S S CO ^ m o c^ ogogggggc I 'Xi »rt ■^ 00 CO *- OOOOOOOOQOOOOOO t£ :D OO -H lO iO_(M lO ^lO lO t-* IC 00 ^ 9 *^ vf 9P^ -i< COS 3'^ 53 ISSSSS OOOOOOO (MOSOOtO'— OiOOirtWe _ oooS co. QO 1-1 ^N ^H ^H CO ooooooooooooooc 5000o»oooiM'^oo<; l>» 1-1 ^ OOOOOOiOOOOOOOOO c; lO c^ O i>- c • OiOOCOOSCCOiO OOQOO SS§ggSg88§? if^"— ccr-oc^ »— t I CTi »0 CC ^ »0 ooooooooooooooc OOOOOOt-OOOO'MOOC §00000000000000 CCOOOOW5CCOOC^»0000 00 CC C^O^^OCC (M ■^ -^^CO (M (M CO Oi C^ lO ^ccic^ coco Cvj OOOOOOOOOOOOOOC O r-o OO c . 5 OOOI-- »0 O '(McoOcoior^-— "O ?sg ooooc 8g§ . _ JOOOOO _ . _?ooooooooo QO CO^UO '^'^ t-~zD ':Ci Oi 00 ^^ osuood«5oi'odM'-^'--t-^^coco'«*<: OOOSO'-^CMCO'^tC^f^OOOiO'— 'C ^-NC^C^iMC^C^(M(M(M(MC^COCOC 1 1I £ • 5 =8 a ^ a-- 2 o >.< « - o z 220 DIVISION OF WATER RESOURCES r-« t>i o (A o u V) < 5J c <: (,; H u a J <• ^ u u ir^OiOOt^C^OC^cocO'-HCOOiOOiM (NQOI>-00CCiO'— 'OOlC^OC-lOOOOr^ 03 00 ^lO O O CC CC CO "^^"^^^ooio •^ CO Tji" iO t^ OT I OO -^ '-H CO ■^ 03 C ro CO co^Oe CC vH ^ w ^ S -^ CO '-H »0 - -^ coco t^oseo »-H ,— ( csi -tr CO GO ■^ "-H Oicoco-<*< r^ Oi'^oocqco OOOOC^cO CO 1-HCO OO Ir^ -"J* U3 t>- OCJOiO i-H OS i-i(OCMOi-t lCO l>-_03 C^OO Oi»0 '-^ Oi CO lO t^ O i-T CO c4" ■-<■ lo o •-*' CO csT t-^ Ol ^H 1-1 ^H CO 1-l^H 1-1 ^H corf Oi t C^COOicDcOOiWSU^OS t— CO-^OliOQOl^OOOi c^oococoi^co^HOcn.iot^co-»**r^ooio OOOCOt^COTriOOC^OOCOi— tCMOlOC^I CO 1-1 1-t OiO^OO'-lt^C^COCOCqOCOCOCOC ^HOlO-H^ c^Tcood cTcor-^i-r ^co-^cdcoc^otp J ss 3 ja si 3 P §ii H = ?i m'3 c s s < ^ ea ^ o ^ ^ 5 !S iJ cc O P-i 0H ^5 53 2 SS^ oo =2. O 03 C3 •n > CO CC 03 — a 3:a ■i .Is — :^^ .. sis e S iujs C3 -a ^ « "> ja - -o S Hfr^ o .§ s ^S ♦^ Zjq 3 » VENTURA COUNTY INVESTIGATION 221 r (/5 a; D J Z CQ W < u o a: o o ■^ lO C^iO to evioo to y SI to O OiQOOs (M 05 CO 0_tO"^CO lO_ CO CO lOOO '^ •as (m' c4" ^ •^ CO o ^ i a a 'C a> L^ BJ- f^ ooor^ ^ 'oj to 1 OS m 1 -^ 1 'S '— < O^C^ 1—1 o_ '0_ ^ lOOiiO-^ uo uoc-1 c^ ci" CO ^ us ■^ CO im" to S) »— ' 'E *~* ,^ ^ ^ COCO ^ CO a> 05 lO -X tM t-l^-HO tOOO !5 oo lO 05 iS o H ^ -<*<(MOCC 05 (MC^ o i>« in 1 C^ lOCCOO too ■«< 1 ^(MCO-H lO oo ^ "o ^ -^ -^ B u) ^■n t^ OicO 1 ■M ll- OS 2 1 — ICO^ ' r>. ICO o o .5f '"' _ ■^-* I^-^ o ot^co-* o ■^ lO I^ C8 C^ CO i-H to ' 1^ CO oS to 4) *"* "■ U < C ^^0 50'^ C^ IO(M Ol a TJ* CO CO CD o •»■«< to ■^ to < O <"3 l-i ci o CO-* cOOi 5^ ; „ CO to 00 t^ r^ wi>-ko C^l 1 •«»* 01 Oi CO >. ^„ t— t CO r-c^co (^ lOO r- irao "« C3 "o ^' CO ^- w ;" ;^" cvT 3 > H CO OCOC^*M ^ i to to to 05 ^ -o oo iO cOGOcn oo 'CO o c^i--. s s, t-^ iQO to lo l^ ■sl l-T rH ^ 1 =^" 00 Oi _M 13 r* CO ^ Tt< t^ >o ' lO J^ '• Oi to CO C^i« OJCO CO 1 o o c^ iOCM 03 lO '■CO ■^^ -*-» ^ ^ \ 1-! co" \ T-i" ^ S) A PS a d 1 1 1 : : : : o s ■3 2 m 1 > 1 1 1 o S ; ; : ; <1 > o .J „;.:■« g a tl o S s S, ' ■§ Antonio jai Vallej ibby-Piri^ pper Oja reek Roa Totals S Is §1 1 &C 1 ^ i 03 V c4 a 03 o > c >aOiJPO §g «> 1 ^ M fo> o<: 1 ■c "s a J.S3 o a 6? •p.sf'S' 1^ »-" te 222 DIVISION OF WATEK RESOURCES Flow tunnel. Excavation Lining TABLE 72 CAMARILLO CANAL From Spreading Grounds to Camarillo Reservoir; Capacity. 200 Second- feet ESTIMATE OF COST 2,300', 7' diameter circular section: 5,400 cu. yds. at 2,150 cu. yds. at $5 00- 20 00. Pressure tunnel. Excavation Lining 3', 7' diameter circular section: Flumes (5' x 12' water section). Pressure pipe (7' diameter) Railroad crossing (7 ' pipe) 1,900 cu. yds. at 800 cu. yds. at 1,100 lin. ft. at 2,000 feet at 100 feet at Temporary work, etc... $5 00. 25 00. $20 00- 17 50- 20 00- Pressure pipe (7J^' diameter) - Flow pipe (7J^' diameter) Highway crossings (5' x 12').. Canal pipeline excavation: Earth excavation Hardpan Backfill 2,800 feet 4,000 feet 400 feet Canal lining Emergency spillways Right of way: Orchard Cultivated Uncultivated (side hill). Farm bridges 220,000 cu. yds. at 100,000 cu. yds. at 50,000 cu. yds. at 66,000 lin. ft. at $20 00- 17 50- 30 00 $0 20- 50. 12- $4 00 25 acres 25 acres 75 acres 25 acres $3,000 1,000. 200- 200. Pumping plant, 200 c. f. s., 87J^ ft.. 17,500 sec. ft. at $10 00. BASE COST Engineering, administration and contingencies — 25%. Interest during construction — rate 6%. $27,000 43,000 $9,500 20,000 $2,000 3,000 $44,000 50,000 6,000 $75,000 25,000 15,000 500 $70,000 30,000 22,000 35,000 5,000 56,000 70,000 12,000 100,000 264,000 16,000 $800,000 175,000 $975,000 245,000 80,000 TOTAL COST $1,300,000 TABLE 73 CONDUIT FROM SATICOY SPREADING GROUNDS TO PLEASANT VALLEY Capacity, 75 Second-feet Station 25 to 500, 75 second-foot capacity: Excavation — Earth Hardpan. Backfill Canal lining Tunnel Pressure pipe, 60". Flow (60") pipe... Flume Station 500 to 702: Excavation^ Earth Hardpan Backfill - Canal lining.-- Railroad crossing-- Flume — Calleguas Creek. Pipe (42") Station 702 to 742... Right of way: Orchard Cultivated Uncultivated Farm bridges Spillways. ESTIMATE OF COST 90,000 cu. yds. at 20,000 cu. yds. at 16,600 cu. yds. at BASE COST Engineering, administration and contingencies- Interest during construction — rate 6% 38,000 lin. ft. 24,000 feet 3,000 feet 3,000 feet 11,000 feet 20,000 cu. yds. at 5,000 cu. yds. at 400 cu. yds. at 18,500 lin. ft. at 100 feet 150 feet 1,600 feet at 3,000 feet at 20 acres 18 acres 50 acres 20 acres $0 20- 50- 12. $3 00. 25 00- 10 00- 8 00- 10 00- $0 20- 50- 12. $2 00- $5 00. $3 00. $3,000 1,000 200 100 -25%. $18,000 10,000 2,000 $8,000 2,500 500 TOTAL COST. $30,000 114,000 60,000 30,000 24,000 11,000 11,000 37,000 3,000 2,000 8,000 9,000 90,000 11,000 $440,000 110,000 33,000 $583,000 VENTURA COUNTY INVESTIGATION 223 TABLE 74 SANTA PAULA BASIN PUMPING PLANTS AND CONDUIT FROM ABOVE WILLARD BRIDGE TO SATICOY SPREADING WORKS ESTIMATE OF COST Headworks at Turner Ditch Intake Lined canal (bottom width 3', depth 2', 1^ to 1 slopes) 36" pipeline .._ 42" pipe line. 48" pipeline 18" pipe feeders 30 wells— 2J^ second-feet equipment for 60-foot lift. Right-of-way, roadways, etc.. 8.000 lin. ft. at $2 50 8,000 lin. ft. at 5 00 8,000 lin. ft. at 6 00. 8,000 lin. ft. at 7 00. 10,000 lin. ft. at 1 50. B.\SE COST Engineering, administration and contingencies — 25%. Interest during construction — rate 6%. 110,000 20,000 40,000 48.000 56,000 15,000 75,000 16,000 TOT.\L COST. $280,000 70,000 21,000 $371,000 TABLE 75 PIRU SPREADING WORKS Plan, 4. '^00-foot Tunnel and Pipe Line Dam and diversion works — Piru Creek: Excavation — Stripping dam foundation. Cut-off wall Rock excavation Levee embankment Concrete and masonry — Dam Cut-off wall Stream bed paving Bank protection Reinforced concrete — Weir chamber and inlet tower Head and wing walls for levee ESTIMATE OF COST 5,600 cu. yds. at 320 cu. yds. at 625 cu. yds. at 3,000 cu. yds. at Gates — 2 — 7' X 16' radial gates. 2 — 5' X 18' radial gates. Tunnel (6.5' net diameter, 4,900' long)- ExcavatioD _ Concrete lining Pipeline — Excavation below South Tunnel portal. 2 — 6' reducers, 6.5' to 5', installed 2,400 lin. ft. pipe at $10.00 Vent pipe, 40'-30', Calco pipe Stilling well and weir control complete 8,700 cu. yds. at 3,400 cu. yds. at 1,000 cu. yds. at $0 50- 4 00- 2 00. 00. $8 00. 10 00- 6 00- 6 00- 2,025 cu. yds. at 320 cu. yds. at 400 cu. yds. at 80 cu. yds. at 193 cu. yds. 107 cu. yds. 300 cu. yds. at $20 00- 11,500- 1,400. $5 00- 20 00- $0 30- Spreading works — Levees 362,600 cu. yds. at $0 15- Strip checking grounds 123 acres at 30 00- Paving and flexible mattress 220,400 sq. ft. at 15- Sluice pipes— basin outlets 2 complete at 750 00 - Outlet from basins — 3 — 36" pipe outlets from upper basin 3 at $450 00- 10 — outlets to spreading grounds- 10 at 350 00- Spillway from basin 2 at 500 00- Right-of-way B.^SE COST Engineering, administration and contingencies- Interest during construction — rate 6% -25%. $2,800 1,280 1,250 $16,200 3,200 2,400 480 6,000 3,000 2,800 $43,500 68,000 $300 100 24,000 100 2,100 $54,390 3,690 33,060 1,500 1,350 3,500 1,000 $39,410 111,500 26,600 98,490 35,000 TOTAL COST. $311,000 78,000 12,000 $401,000 224 DIVISION OF WATER RESOURCES TABLE 76 PIRU CREEK SPREADING WORKS Alternate Plan ESTIMATE OF COST Dam and diversion works — Piru Creek: Excavation^ Stripping foundation.- 3,600 cu. yds. at $0 50.-- Cut-offwall 500cu.yds.at 4 00. Stream bed and banks 400 cu. yds. at 20, Stream bed and banks 3,600 cu. yds. at 50. Levee on right bank 5,000 cu. yds. at 20. Concrete — Mass concrete in dam 4,850 cu. yds. at $8 00- Cut-off wall 500cu. yds. at 6 00- Paving stream bed and banks 1,300 cu. yds. at 8 00- Radial gates for sluiceway 2 at 2,000- Diversion canal and inlet works^ Excavation settling basin 260 cu. yds. at $0 50- Cut and cover section 1,400 cu. yds. at 50. Opencutwork 71,600 cu. yds. at 20- Syphontrench 2,800 cu. yds. at 100. Concrete — Lining of inlet basin and weir wall 32 cu. yds. at $15 00- Cut and cover section 142 cu. yds. at 15 00. Canallining 3,750 lin. ft. at 2 65. Canallining 2,800 lin. ft. at 2 40- Canallining 700 lin. ft. at 5 00. Inlet box to syphon 32 cu. yds. at 15 00. Concrete pipe for syphon 570 feet at 15 00. Sluicepipes 300 lin. ft. at $5 00. Slidegates 2 at 250 00. Slidegates 2 at 1,000 00- Tunnel— Excavation 4,300 cu. yds. at $5 00. Concrete lining 1,620 cu. yds. at 20 00. Concrete head walls 50 cu. yds. at 20 00. Pipe line to spreading grounds — 2,300 feet— 48 "pipe installed at $6 00 $13,800 Stilling well and weir 2,100 $1,800 2,000 80 1,750 1,000 $6,630 $38,800 3,000 10,400 4,000 56,200 $130 700 14,320 2,800 17,950 $480 2,130 9,940 6,720 3,500 480 8,550 31,800 $1,500 500 2,000 4,000 $21,500 32,400 1,000 Spreading works- Dikes 362,600 cu. yds. at $0 15 $54,390 Strip checking grounds.-. 123 acres at 30 00 3,690 Rock mattress dike protection. 220,400 cu. yds. at 15 33,060 Sluicepipes 2completeat 750 00 1,500 Outlets — upper basin 3completeat 450 00 1,350 Outlets — basin to ground lOcompleteat 350 00 3,500 Spillway basins 2completeat 500 00 1,000 54,900 15,900 98,490 Right-of-way 35,000 BASE COST $321,000 Administration, engineering and contingencies— 25% 80,000 Interest during construction — rate 6% 12,000 TOTAL COST _. $413,000 VENTURA COUNTY INVESTIGATION TABLE 77 MONTALVO SPREADING WORKS Diversion dam: Excavation -. ..,.„ 4,200 cu. yds. at Sheet piling steel ....- 364,000 lbs. at Reinforced concrete piling. Concrete — Floor slab and footing.. Piers and walls - Deck and beams .- Reinforcing steel Gates— 4 roller gates 1—20' Taintorgate... 1 — Iti' Taintor gate, with automatic control. Footbridge .. Rockfill and cleaning 1,440 at 690 cu. yds. at 730 cu. yds. at 12 cu. yds. at 134,000 lbs. at at at $0 50 05- 2 00. 8 00. 10 00. 12 50- 06. 2,.500 1,500. BASE COST Main canal: 400 second-foot capacity, 2,400 lin. ft. Bottom iridth, 15 feet; water depth, 5 feet; side slopes, IM to 1; grade .00025 . Excavation - Concrete lining Turnout structure, concrete Turnout structure, reinforcing steel- 3 — 5' X 10' radial gates 16,000 cu. yds. at 72,000 sq. ft. at 100 cu. yds. at 9.100 lbs. at Levee and paving, above desilting basin: Levee Flexible mattress or paving 15,000 cu. yds. at 50,000 sq. ft. at Desilting basins: Levees Flexible mattress and pa\'ing Feed canal, outlets to basin Excavation for inside channel, included in levee fills Lining outlets and sluicing canal Spillway lining Sluicing gates Pipe for sluicing outlets 180,000 cu. yds. at 160,000 sq. ft. at 45,000 sq. ft. 5,000 sq. ft. 300 ft. By-pass canal (lined, bottom 6', depth 3', side slope V/i to 1). 2,500 feet Distributing canals: Above Del Norte Avenue — Lined canal 5,000 ft. Unlined canal 2,000 ft. Unlined canal 2,500 ft. Turnouts, gates and wasteways Spreading dikes and road levees, above Del Norte Avenue — Road with levees 15,000 ft. Minor levees 20,000 ft. .additional for roads along canal $0 15 15- 12 50 06- 500 00- fO 20 15 $0 20- 15- 15- 15- 1,000 5 00. $3 20- $3 00- 25- 20- $0 30- 15- $2,100 18,200 5,520 7,300 150 8,040 10,000 1,500 1,500 1,200 1,610 S2,400 10,800 1,250 550 1.500 $3,000 7,500 I3o,000 24,000 2,000 6,750 750 2,000 1,500 $15,000 500 500 4,000 $4,500 3,000 500 ?60.000 10,500 73,000 8,000 TOTAL above Del Norte Avenue- Spreading works below Del Norte Avenue: Distributing canals — Pi pe under Del Norte .\ venue Lined canal, section Lined canal, section Unlined canal Turnouts and wasteways Spreading dykes and road levees- Road width levees Minor levees 200 ft. 2,500 ft. 1,200 ft. 300 ft. 15,000 ft. $5 00. 2 40. 2 00- SO- SO 30 $1,000 6,000 2,400 900 2,200 $4,500 3,000 $12,500 TOTAL below Del Norte Ave. Total above and below Del Norte Avenue . Right-of-way B.\SE COST _ Engineering, administration and contingencies — 25%. I nterest duri ng construction — rate 6% TOTAL COST. $20,000 $348,000 15 — S36-; -S3T5 226 DIVISION OF WATER RESOURCES Diversion dam: Excavation . Mass concrete Formed concrete Paving concrete Reinforcing steel--. -- Flexible mattress Radial gates Steel rails, secondhand. TABLE 78 VENTURA RIVER SPREADING WORKS ESTIMATE OF COST 1,000 cu. yds. at $0 50 600 cu. yds. at 8 00 125 cu. yds. at 12 00 100 cu. yds, at 10 00. 0,000 lbs. at 06. 6,000 sf). ft. at 20. 1 at $500, 2 at S300 Diversion channel, 500' long: Excavation Lining Covered section Cozy Dell Creek, diversion levee (1,000'— 5' ht.): Levees abo\e and below diversion dam: 65 tons at 5,000 cu. yds. at 8,000 sq. ft. at 190 cu. yds. at 5,000 cu. yds. at 20 00 $0 20- 15- 20 00- SO 20. 5,000 cu. yds. from channel 11,000 cu. vds. at 5,000 sq. ft. at Flexible mattress Road levees (20,000 lin. ft. at 1.6 cu. yd. per ft.): 32,000 cu. yds. at Contour spreading levees (120,000 lin. ft. at 1.0 cu yd. per ft.): 120,000 cu. yds. at Cross-channel levees: 85,000 cu. yds. at Cross-channel controls: 20-20' opening at 32-20' opening at Laterals and outlets Right of- way SO 20- 20 15- $0 10- ?0 20- $600- 750. BASE COST - - Engineering, administration and contingencies — 25%. Interest during construction — rate 6% $500 4,800 1,500 1,000 600 1,200 1,100 1,300 $1,000 1,200 3,800 $1,000 $2,200 1,000 $4,800 $12,000 $17,000 $12,000 24,000 TOTAL COST- $6,000 $1,000 $2,200 1,000 $4,800 $12,000 117,000 $36,000 4,000 14,000 $110,000 28,000 4,000 $142,000 TABLE 79 PIPE LINE, MATILIJA RESERVOIR TO OJAI VALLEY Capacity, 25 Second- feet Estimate is only approximate as no detailed survey was made, on field reconnaissance and U. S. G. S. topographic maps. Station — 180 24" pipe required Station 180—330 30" pipe required Excavation for 24" pipe-^.75 cu. yds. per foot Excavation for 30" pipe-^1.00 cu. yds. per foot Excavation: 4,000 lin. ft. 2,800 lin. ft. 4,000 lin. ft. 7,200 lin. ft. 15,000 lin. ft. The estimate of length and of excavation is based Backfill.- Ventura River crossing Spun concrete pipe laid in trench: 24" diameter — 30" diameter - 30,000 cu. yds. at $2 25. 75- 2 00. 40. 1 00- $0 10. 8,700 ft. high head 9,300 ft. low head 15,000 ft. tow head $4 05. 3 25. 3 75- Right-of-way and stripping. BASE COST ------ Engineering, administration and contingencies — 25%. Interest during construction~6% rate $9,000 2,100 8,000 2,900 15,000 $35,000 30,000 56,000 $37,000 3,000 3,000 121,000 3,000 TOTAL COST- SI 67,000 41,750 6,250 $215,000 VENTURA COUNTY INVESTIGATION 00' TABLE 80 COST OF LOS ALAMOS RESERVOIR With 135-foot Slab and Buttress Dam Crest of dam, elevation 2,400 feet, U. S. G. 3. datum Crest of spillway, ele%-ation 2,380 feet Dam and spillway: Excavation — Gravel — wet Loose shale Footing and cut-off trenches Concrete — Buttresses Buttress footings. . Struts and walks. . Slabs Cut-off walls Spillway walls Bucket and apron. Parapet Drilling and grouting Outlets- Concrete trash racks Trash racks. Steel pipe Xeedle valves — 36-inch- Slide gates — 36-inch Reservoir^: Linds Transnoission line. 26" gas line 22" gas line 8" oil line Telephone line Clearing — brush. _ trees.. - Capacity of reservoir, 10,400 acre-feet Capacity of spillway, 61,000 second-feet 27,400 cu. yds. at $1 50 $41,100 5,450 cu. yds. at 1 00- 5,500 6,160 cu. yds. at 5 00 30,800 $77,400 32,800 cu. yds at. $18 00 $590,000 4,900 cu. yds. at 15 00 73,500 600 cu. yds. at 25 50 15,300 8,040 cu. yds. at 18 50 149,000 1,260 cu. yds. at 15 00 18,900 300 cu. yds. at 23 50 7,100 2,480 cu. yds. at 16 50 40,900 80 cu. yds. at 18 50 1,500 896,200 5 10 ft. of dam at 25 00 $12,800 12,800 10 cu. yds. at $18 50 $200 1,500 lbs. at 10 200 160 ft. at 13 50 2,200 2 at 7,600 00 15,200 2 at 4,800 00 9,600 27,400 $5,000 1.26 mi. at $25,000 00 31,500 .89 mi. at 50,000 00 44,500 .89 mi. at 50,000 00 44,500 .60 mi. at 40,000 00 24,000 .94 mi. at 2,000 00 1,900 120 acres at 20 00 2,400 10 acres at 50 00- 50O Sub-total $1,168,100 .Administration, engineering and contingencies, 25% 292,000 Interest during construction — 6% rate — 1 year period 88,900 TOT.iL COST $1,549,000 ' Xo charge for relocating the State highway is included in estimate. 228 DIVISION OF WATER RESOURCES TABLE 81 COST OF LIEBRE CREEK DIVERSION TO LOS ALAMOS RESERVOIR Head works: Liebre Creek — Dam — Excavation. Concrete... Headgate. West Fork- Dam — Excavation . Concrete Canal: Liebre Creek- West Fork- Combined — Flumes: Liebre Creek- West Fork- Combined — ■ -Excavation Concrete lining Excavation Concrete lining Excavation — Ditcli . . Trench. Backfill Concrete lining 60-inch pipe 60-inch gate -Metal flume Sub-structure.. Metal flume Sub-structure.. Metal flume Sub-structure. - Inlet structure. Sand boxes and spillways . 32 cu. yds. at $3 00 $100 32 cu. yds. at 25 00 800 1 at 250 00 250 143 cu. yds. at $3 00 430 124 cu. yds. at 25 00 3,100 I at 250 00 $0 50 250 15,200 cu. yds. at $7,600 540 cu. yds. at 20 00 10,800 5,430 cu. yds. at 50 2,720 310 cu. yds. at 20 00 6,200 380 cu. vds. at 50- 190 400 cu. yds. at 50 200 300 cu. yds. at 25 80 20 cu. yds. at 20 00 400 70 ft. at 10 00 700 1 at 150 00 $2 35 150 475 lin. ft. at $1,120 9,570 F.B.M. at 110 00 per M. 1,050 100 lin. ft. at 2 00 200 1,020 F.B.M. at 110 00 per M. no 400 lin. ft. at 2 60 1,040 20,670 F.B.M. at 110 00 per M. 2,270 1 at 200 00 200 Sub-total Administration, engineering and contingencies, 25%. Interest during construction — 6% rate — J^ year $400 $4,930 29,040 400 $40,360 10,090 1,510 TOTAL COST. $51,960 TABLE 82 COST OF SPRING CREEK RESERVOIR ON PIRU CREEK With 185-foot Variable Radius Concrete Arch Dam Crest of dam, elevation 2,180 feet, U. S. G. S. datum Crest of spillway, elevation 2,160 feet Dam (including spillway): Excavation — Gravel and talus. ., Rock — wet Dry Concrete — Mass — arch Outlet tower Reinforced — parapets Outlet tower. Grouting and seals Outlets — Trash racks Steel pipe — 36-inch Roller gates — 4' x 4' Needle valves — 36-inch. Backfill Reservoir': Land Transmission line. Clearing — brush. . Trees.. Capacity of reservoir, 20,200 acre-feet Capacity of spillway, 73,000 second-feet 63,900 cu. yds. at 8,200 cu. yds. at 20,500 cu. yds. at $1 50 3 50 2 50 $8 50 8 50 17 25 17 25 $30 00 $0 10 13 50 5,300 00 10,100 00 $0 25 No cost $25,000 00 20 00 50 00 $95,900 28,700 51,300 $175,900 1,177,570 16,500 33,650 4,180 136,100 cu. yds. at 1,100 cu. yds. at 140 cu. yds. at 515 cu. yds. at . $1,156,900 9,350 2,420 8,900 550 ft. of dam at 1,500 lbs. at 200 ft. at 2 at 2 at 16,700 cu. yds. at $16,500 $150 2,700 10,600 20,200 $4,180 0.75 mi. at 148 acres at 30 acres at $18,800 2,960 1,500 Sub-total ... $1,431,060 Administration, engineering and contingencies, 25% 357,760 Interest during construction — 6% rate — IJ^-year period 165,820 TOTAL COST $1,954,640 ' Does not include cost of relocation of State highway. VEXTURA COl^N'TV IXVESTIGATIOX 229 TABLE 83 COST OF SPRING CREEK RESERVOIR ON PIRU CREEK With 283-fc)ot Variable Radius Concrete Arcli Dam Crest of d;im. elevation 2,278 feet, U. S. G. S. datum Crest of spillway, elevation 2,261 feet Dam: Excavation — Gravel and talus _ Rock — wet - - Dry Concrete^ Mass — arch section (iravity section _ Outlet tower Reinforced -parapets Outlet tower Grouting and seals. Outlets- Trash racks, . Steel pipe — 36-inch Roller gates — 4' x 4' Needle valves — 36-inch. Backfill Spillway (shaft and tunnel tj-pe): Excavation^ Inlet.. Shaft Tunnel- Weir. Concrete^ Mass — Vfeir Reinforced — paving Shaft and tunnel lining. Reservoir': Land Transmission line Clearing — brush Trees ... Capacity of reservoir, 61,500 acrc-fcet Capacity of spillway, 73,000 second-feet 80,200 cLi. yds. at 10,500 cu. yds. at 50,500 cu. yds. at SI 50- 3 50 2 50 306,900 cu. yds. at 21,400 cu. yds. at 1,600 cu. yds. at 180 cu. yds. at 620 cu. yds. at $8 50 8 50 8 50 17 25- 17 25 700 ft. of dam at $30 00 1,500 lbs. 250 ft. 2 18,900 cu. yds. at 35,180 cu. yds. at 10,740 cu. yds. at 12,960 cu. yds. at 16,880 cu. yds. at 14,280 cu. yds. at 710 cu. yds. at 3,750 cu. yds. at SO 10- 13 50- 6,000 00- 14,300 00 SO 25- $2 50 8 00- 6 50- 2 50- S9 50- 14 50- 20 25- 2.8 mi. 260 acres 50 acres No cost S25,000 00--- 20 00--. 50 00- _- $120,300 36,800 126,300 $2,608,700 181,900 13,600 3,110 10,700 $21,000 $150 3,380 12,000 28,600 $4,730 $88,000 85,900 84,200 42,200 $135,700 10,300 75,900 $70,000 5,200 2,500 $283,400 il8,010 21,000 44,130 4,730 221,900 7,700 Sub-total $3,771,170 -Administration, engineering and contingencies, 25% 942,790 Interest during construction — 6% rate — 2}^year period. 750,930 TOT.\L COST $5,464,890 Does not include cost of relocation of State highway . 230 DIVISION OF WATER RESOURCES TABLE 84 COST OF SPRING CREEK RESERVOIR ON PIRU CREEK With 185-fcx3t Gra\ity Concrete Dam Crest of dam, elevation 2,180 feet, U. S. G. S. datum Capacity of reservoir, 20.200 acre-feet Crest of spillway, elevation 2,160 feet Capacity of spillway, 73,000 second-feet Dam (including spillway): Excavation — Gravel — wet Common — dry Rock — wet Dry Cut-off trench Concrete — • Reinforced — parapets Gate towers and house. Grouting, drainage and seals - Outlets— Steel pipe — 36-inch Trash racks Roller gates — 4' x 4' Needle valves — 36-inch Backfill. Reservoir': Land Transmission line- Clearing — brush. . Trees. . 65,500 cu. yds, .at $1 50 $98,.300 29,800 cu. yds. , at 40 11,900 13,200 cu. yds .at 3 50 46,200 27,700 cu. yds. .at 2 50 69,300 1,680 cu. yds, yds. .at .at 6 00 S6 00 10,100 219,300 cu. .- $1,315,800 250 cu. yds .at 17 25 4,310 90 cu. yds. at )fdam at at 17 25 S90 00 S13 50 1,550 490 ft. c 544,100 140 ft. $1,890 1,500 lbs at 10 150 2 at 5,300 00 10,600 2 yds. at at 10,100 00 SO 25 No cost 20,200 43,200 cu. $10,800 0.75 mi. at $25,000 00 118,800 148 acres at 20 00 2,960 30 acres at 50 00 1,500 $235,800 1,321,660 44,100 10,800 23,260 Sub-total . $1,668,460 Administration, engineering and contingencies, 25% 417,120 Interest during construction — 6% rate — 1-year period 127,010 TOTAL COST $2,212,590 ' Does not include cost of relocation of State highway. VENTURA COUNTY INVESTIGATION 231 TABLE 85 COST OF SPRING CREEK RESERVOIR ON PIRU CREEK With 280-foot Gravity ("oncrete Dam Crest of dam, elevation 2,275 feet, U. S. G. S. datum Crest of spillway, elevation 2,258 feet Dam: Excavation — Gravel — wet Common — dry Hock — wet - Dry Cut-off trench Capacity of reservoir, (iO.lOO acre-feet Capacity of spillway, 73,000 second-feet 94,500 cu. yds. at 40,100 cu. yds. at 21,800 cu. yds. at 03,400 cu. yds. at - 2,220 cu. yds. at Concrete — Mass.... 510,900 cu. yds. at Reinforced — parapets 330 cu. yds. at Gate towers and house 120 cu. yds. at U 50- 40- 3 50- 2 50- 6 00- $6 00 17 25- 17 25 Grouting, drainage and seals. Outlets- Steel pipe — 3C-inch Trash racks Roller gates — 4' x 4' Needle valves — 36-inch (iGO ft. of dam at $90 00- 210 ft. 1,500 lbs. 2 Backfill. Spillway (shaft and tunnel type): Excavation — Inlet Shaft Tunnel Weir Concrete — Mass— weir Reinforced — paving Shaft and tunnel lining. .53,000 cu. yds. at 35,180 cu. yds. at 10,740 cu. yds. at 12,900 cu. yds. at 10,880 cu. yds. at 14,280 cu. yds. at 710 cu. yds. at 3,750 cu. yds. at S13 50- 10. 0,000 00- 14,300 00- $0 25- $2 50- 8 00- 50- 2 50- $9 50- 14 50 20 25- Reservoir': Land Transmission line- Clearing — brush.. Trees.. 2.8 mi. at 200 acres at 50 acres at No cost S25,000 00... 20 00... 50 00 .- $141,800 10,000 70,300 158,500 13,300 $3,101,400 5,090 2,070 $59,400 $2,840 150 12,000 28,000 $13,300 $88,000 85,900 84,200 42,200 $13.5,700 10,300 75,900 $70,000 5,200 2,500 $405,900 3,109,100 59,400 43,590 13,300 221,900 700 Sub-total...- $4,231,250 .■Vdministration, engineering and contingencies, 25% 1,057,810 Interest during construction — 6% rate — 2-year period 'e63!780 TOT.\L COST Does not include cost of relocation of State highwav. $5,952,840 232 DIVISION OF WATER RESOURCES TABLE 86 COST OF SPRING CREEK RESERVOIR ON PIRU CREEK With 187-foot Rock Fill Dam Crest of dam, elevation 2,182 feet, U. S. G. S. datum Crest of spillway, elevation 2,lt)0 feet Dam: Diversion of stream — ■ Excavation — Open cut Tunnel Concrete — Reinforced — tunnel lining. Mass — tunnel plug Capacity of reservoir, 20,200 acre-feet Capacity of spillway, 73,000 second-feet Excavation — Gravel and talus Rock — dry. . - - . . - Cut-off trench. Rockfill— Dumped Placed Concrete — Mass — cut-off wall Reinforced — subslab Laminated slab- Parapets Crest paving -- Grouting cut-off Backfill Spillway (side-channel type): Excavation — waste Reinforced concrete lining Outlet: Steel pipe — 60-inch Trash racks Slide gate — 4' x 5' N eedle valve — 60-inch Reservoir': Land Transmission line Clearing brush Trees No cost 75 mi. at $25,000 00-- 148 acres at 20 00 . - 30 acres at 50 00 . 7,460 cu. Vds. at $2 50 $18,700 8,420 cu. yds. at 6 50 54,700 2,260 cu. vds. at 20 25 45,800 760 cu. yds. vds. at at 8 50 $0 50 6,460 191,500 cu. $95,800 53,400 cu. vds. at 2 50 133,500 3,100 cu. yds. vds. at at 6 00 $1 50 18,600 564,300 cu. $846,500 67,000 cu. yds. at 3 25 217,800 6,900 cu. vds. at $8 50 $58,700 5,340 cu. vds. at 14 50 77,400 5,620 cu. vds. at 16 75 94,100 120 cu. yds. at 17 25 2,070 270 cu. yds. at jfdamat 14 50 S125 00 3,920 490 ft. ( $61,300 60,300 cu. yds. at 25 $15,100 602,000 cu. vds. at $1 00 $602,000 8,400 cu. yds. ■ at at 16 00 $22 50 134,400 530 ft. $11,900 1,500 lbs at 10 150 1 at 6,700 00 6,700' 1 at 14,200 00 14,200 $18,800 2,960 1,500 $125,060 247,900 236,190 61.300 15,100 32,950 23,260 Sub-total - - $2,543,060 Administration, engineering and contingencies, 25% 635,800 Interest during construction — 6% rate — 2-year period 399,000 TOTAL COST. $3,577,860 Does not include cost of relocation of State highway. VKNTIRA (OUNTV INVESTIGATION' 233 TABLE 87 COST OF BLUE POINT RESERVOIR ON PIRU CREEK With lb5-fcxDt Earth Fill Dam Crest of dam. elevation 1.280 feet (1,235 U. S. G. S. datum) Capacity of reservoir, 20,000 acre-feet Crest of spillway, elevation 1,255 feet Capacity of spillway, 98,000 second-feet Dam: Diversion of stream — Excavation- Open cut 21,300cu. yds. at $1 50 $32,000 Tunnel 14,200 cu. yds. at 6 50 92,300 Concrete — 3,450 cu. yds. at $20 25 69,900 Mass — tunnel plug 730 cu. yds. at 10 00 7,300 Excavation — Gravel -. 4.=18,500 cu. yds. at $0 50 $229,300 Rock — stripping 122,200cu. vds. at 1 50 183,300 Cut-off trench .-. Iti.TOO cu. vds. at 3 50 58,500 Toe-wall trench 220 cu. yds. at 6 00 1,300 Earth fill— Imper%-ious> 1,124,300 cu. yds. at $0 40 $449,700 Per\-ious= .-- 270,400 cu. yds. at 35 94,600 Concrete facing — Reinforced— slab 4.750 cu. yds. at $15 50 $73,600 Toe-wall 220 cu. yds. at 13 75 3,000 Backfili 94,200 cu. yds. at $0 25 $23,600 .Spillway: Excavation — Gravel 21,300 cu. vds. at $0 50 $10,600 Rock— channel. _ 1,100,000 cu. vds. at 100 1,100,000 Cut-off wall 240cu.yds.at 6 00 1,400 Concrete — Reinforced— lining 9,930 cu. yds. at 16 00 158,900 Cut-offwall 240cu.yds.at 13 75 3,300 Outlet: Steel pipe— 60-inch -• 1,100 feet at $22 50 $24,800 Concrete shell for pipe llOcu. vds.at 10 00 1,100 Backfill 7,760 cu. yds. at 25 1,900 Concrete trash rack structure 10 cu. yds. at 22 50 200 Trashrack 1,500 lbs. at 10 200 Slide gate— 4' X 5' 1 at 6,000 00 6,000 Xeedle valve— 60-inch 1 at 12,700 00 12,700 Reservoir: Lands and improvements $4,500 Clearing— brush 190 acres at $20 00 3,800 Trees .. 40 acres at 50 00 2,000 $2Ol,.50O 472,400 544,300 76,600 23,600 1,274,200 46,900 10,300 Sub-total $2,649,800 Administration, engineering and contingencies, 259c 662,500 Interest during construction — 6% rate — 1-year period 201,700 TOTAL COST : $3,514,000 » Includes cut-off trench backfill. ' Assumed 35 ^ of material required would be obtained from excavation. 234 DIVISION OF WATER RESOURCES TABLE 88 COST OF DEVIL CANYON RESERVOIR ON PIRU CREEK With 185-foot Earth Fill Dam Crest of dam, elevation 1,220 feet (1,175 feet U. S. G. S. datum) Capacity of reservoir. 41,300 acre-feet Crest of spillway, elevation 1,195 feet Capacity of spillway, 10o,000 second-feet Dam: Diversion of stream — Excavation — Open cut Tunnel Concrete — Reinforced — tunnel lining Mass — tunnel plug Excavation — Gravel Bock — stripping Cut-off trench, _ Toe-wall trench. 176,000 cu. vds. at SI 50 526,400 18,120 cu. yds. at 6 50 117,800 4.430 cu. vds. at 20 25 89,700 730 cu. cu. yds. vds. at at 10 00--,-.-. $0 50 7.300 ■08,500 S354.250 56,200 cu. vds. at 1 50 84,300 9,000 cu. vds. at 3 50 31,500 260 cu. yds. at 6 00 1,560 Earth fill- Impervious' 2,142,000cu. yds. at $0 40 $856,800 Pervious^ 468,600 cu. yds. at 35 164.010 Concrete facing — Reinforced— slab 4,000 cu. vds. at $15 50 $62,000 Toe-wall 260 cu. yds. at 13 75 3,580 92,700 cu. yds. at SO 25 $23,200 Spillway: Excavation — Gravel 2,200 cu. yds. at $0 50 SI. 100 Rock— channel 820,000 cu. yds. at 100 820,000 Cut-offtrench 520 cu. yds. at 6 00 3,120 Concrete — Reinforced— lining 11,780 cu. yds. at 16 00 188,500 Cut-offwall 610cu.yds.at 13 75 8,380 Outlet: Steel pipe— 60-inch 1.400 ft. at $22 50 $31,500 Concrete shell for pipe- 120 cu. vds. at 10 00 1.200 Backfill 8,960 cu. yds. at 25 2.240 Concrete trash rack structure 10 cu. vds. at 22 50 200 Trashrack 1,500 lbs." at 10 200 Slide gate— 4' X 5' 1 at 6,860 00 6,860 Needle valve— 60-inch 1 at 14,600 00 14,600 Reservoir: Lands and improvements $14,500 Clearing— brush 290 acres at $20 00 5,800 Trees 29 acres at 50 00 1,500 $241,200 1,020,810 65,580 23,200 1,021,000 56,800 21,800 Sub-total $2,922,000 Administration, engineering and contingencies, 25% 730,500 Interest during construction — 6% rate — IJ^year period 338,600 T0T.4.L COST 1 $3,991,100 1 Includes cut-off trench backfill. ' Assumed 35% of material required would be obtained from excavation. VENTURA COUNTY IN VKSTKIATION 235 TABLE 89 COST OF COLD SPRING RESERVOIR ON SESPE CREEK With 215-foot I'arth Fill Dam Crest of dam, elevation 3,425 feet (assumed datum) Capacity of reservoir, 42,990 acre-feet Crest of spillway, elevation 3,400 feet Capacity of spillway, 23.,';00 second-feet Dam: Diversion of stream^ Excavation — Opencut -- 4,000 cu. vds. at ?1 50 _ 16,000 Tunnel 5,530 cu. yds. at 10 00 __ 55,300 Concrete — • Reinforced— tunnel lining -.. 2,200 cu. yds. at 23 75 52,300 Head-walls and paving 530 cu. yds. at 19 50 10,.300 Mass— tunnel plug 285 cu. yds. at 13 50 3,850 Excavation — Common 321,200 cu. yds. at $0 50 S160,600 Rock— cut-off trench 34,200 cu. yds. at 3 50 119,700 Toe-wall trench 220 cu. yds. at 5 00 1,110 Earth fill- Impervious l,190,000cu. yds. at $0 40 $476,000 Fergus' 702,000 cu. yds. at 35 245,700 Concrete facing — Reinforced— slab 5,780 cu. yds. at $19 00 $109,800 Toe-wall 220 cu. yds. at 17 25 3,800 Backfill - 11,100 cu. yds. at $0 25..- - _ $2,780 Spillway: Excavation — Rock— loose 52,600 cu. vds. at $150 $78,900 Cut-offtrench 70 cu. yds. at 5 00 350 Concrete — Reinforced— lining - 2,460 cu. yds. at 819 50 $48,000 Cut-off wall 70cu. yds. at 16 50 1,160 Outlet: Steel pipe— 60-inch 970 ft. at $22 50 $21,800 Concrete trash rack structure 10 cu. yds. at 26 00 260 Trashracks 1,500 lbs. at 10 150 Slide gate— 4' X 5' 1 at 7,500 00 7,500 Needle valve— 60-inch 1 at 15,900 00 15,900 Reservoir: Land and improvements $4,000 Clearing— brush 350 acres at $20 00 7,000 Trees 35 acres at 50 00 1,750 Construction road 2 mi. at 7,500 00 15,000 $127,750 n,700 1 13,600 2,780 79,250 49,160 45,610 12,750 15,000 Sub-total $1,449,010 Administration, engineering and contingencies, 25%_ 362,250 Interest during construction — 6% rate — -IJ^-year period 167,900 TOTAL COST $1,979,160 After deducting 186,000 cubic yards placed in fill from stripping. 236 DIVISION OP WATER RESOURCES TABLE 90 COST OF TOPA TOPA RESERVOIR ON SESPE CREEK With 240-foot Rock Fill Dam Crest of dam, elevation 2,325 feet (2,381 feet, U. S. G. S. datum) Capacity of reservoir, 23,800 acre-feet Crest of spillway, elevation 2,300 feet Capacity of spillway, 53,000 second-feet Dam: Diversion of stream — Excavation — Opencut 3,670 cu. yds. at $150 $5,500 Tunnel 6,950 cu. yds. at 8 00 55,600 Cut-off trench 70 cu. yds. at 6 00... 420 $61,520 Concrete — Reinforced— tunnel lining 2,320 cu. yds. at $23 50 Head-walls, etc 310 cu. yds. at 22 25 Mass— tunnel plug 450 cu. yds. at 13 25 Excavation — Gravel -. 151,400 cu. yds. at $0 50 Rock— stripping 40,100 cu. yds. at 2 50 Cut-oiT trench 1,890 cu. yds. at 6 00 Rockfill- Dumped 929,500 cu. yds. at $150 $1,394,200 Placed 80,700 cu. yds. at 3 25 262,300 Concrete — Mass— cut-off wall 1,890 cu. yds. at $12 75 $24,100 Reinforced— subslab 8,020 cu. yds. at 18 25 146,400 Laminated slab _ 8,010 cu. yds. at 20 50 164,200 Parapets 130 cu. yds. at 2100 2,730 Crown paving 280 cu. yds. at 18 25- 5,110 Grouting cut-off 500ft.ofdamat $100 00 $50,000 Backfill 6,000 cu. yds. at $0 25 $1,500 Spillway (side-channel type): Excavation — Rock— cut-off trench 200 cu. yds. at $6 00 $1,200 Waste 270,500 cu. yds. at 100 270,500 Concrete — Reinforced— lining 6,460 cu. vds. at $19 25 $124,400 Cut-off wall... 200cu.yds.at 16 50 3,300 Outlet: Steel pipe— 60-inch 830 ft. at $22 50 $18,700 Trash rack structure 10 cu. vds. at 25 75 260 Trashrack 1,500 lbs." at 10 150 Slide gate— 4' X 5' 1 at 7,700 00 7,700 Needle valve— 60-inch 1 at 16,400 00 16,400 Reservoir: Land and improvements $400 Clearing— brush 150 acres at $20 06 3,000 Trees 30 acres at 50 00 1,500 67,360 187,300 1,656,500 342,540 50,000 1,500 43,210 4,900 Construction road 10 5 mi. at $20,000 00 _ _. $210,000 — 210,000 Sub-total $3,024,230 Administration, engineering and contingencies, 25% 756,060 Interest during construction— 6% rate— 2-year period 474,430 TOTAL COST $4,254,720 VENTUKA e'OUNTV INVKSTKiATION 237 TABLE 91 COST OF MATILIJA RESERVOIR ON MATILIJA CREEK With 170-toot Rock Fill Dam Crest of dam, elevation 1,155 feet, U. S. (!. S. datum Crest of spillway, elevation 1,130 feet Dam: Diversion of stream — Excavation — Open cut - - Tunnel Concrete — Reinforced— tunnel lining. Mass — tunnel plug Excavation — Common Rock — stripping Cut-off trench. Rockfill: Dumped- Placed,.- BackfilL Concrete — Mass — cut-off wall Reinforced — subslab Laminated slab. Parapet Crown paving-.. Grouting cut-off. Spillway: Excavation Reinforced concrete lini'ng. Outlet: Steel pipe — 36-inch __ Trash rack structure Trash rack .. Concrete pi pe cover Backfill Slide gate Needle valve Reservoir: Land and improve xents. Clearing Capacity of reservoir, 8,150 acre-feet Capacity of spillway. 27,000 second-feet 3,440 cu. yds. at 2,160 cu. yds. at 660 cu. yds. at 200 cu. yds. at $1 50 U 50 21 75 11 75 $0 50 2 50 6 00 $1 50 3 25 $5,160 24,800 14,400 2,350 53,500 cu. yds. at 41,700cu. vds. at 3,260 cu. yds. at $26,800 104,300 19,600 476.000 cu. yds. at 62,300 cu. yds. at $714,000 202,500 3,890 cu. yds. at 3,260 cu. yds. at 5,560 cu. yds. at 5,270 cu. yds. at 160 cu. yds. at 360 cu. yds. at $0 25 Sll 25- 16 50_ 18 75. 19 25. 16 50 640 ft. of dam at $125 00 11,400 cu. yds 715 lin.ft. at 10 cu. yds. at 1,500 lbs. at 70 cu. yds. at 2,100cu. yds. at 1 at 1 at $17 50 $13 50. 24 00. 10- 11 25. 25. 5,850 00- 9.200 00 160 acres at $20 00 $970 $36,700 91,700 98,800 3,080 5,940 $80,000 $199,500 $9,650 240 150 790 520 5,850 9,200 $45,000 3,200 $46,710 150,700 i,500 970 236, 220 000 199,500 26,400 48,200 Sub-total .Administration, engineering and contingencies — 25% Interest during construction — 6% rate — ^IJ^-year period . $1,705,200 426,300 197,500 TOTAL COST $2,329,000 All excavation used in dam, assuming 50% waste. 238 DIVISION OF WATER RESOURCES TABLE 92 COST OF CAMARILLO RESERVOIR ON CONE JO CREEK With 80-foot Earth Fill Dam Crest of dam, elevation 235 feet, U. S. G. S. datum Capacity of reservoir, 8,280 acre-feet Crest of spillway, elevation 215 feet Capacity of spillway, 10,000 second-feet Dam: Excavation — Stripping dam base Toe-wall _ Core-wall Steel-sheet piling cut-off walL Concrete — reinforced — Face-slab Toe-wall Core-wall 2,020 cu. yds. at 180 cu. yds. at 6,010 cu. yds. at $0 50 50 1 00-- $75 00 $16 00 14 25 16 00 $1,000 100 6,000 ?7,100 11,600 155 tons at $11,600 2,480 cu. yds. at 180 cu. yds at 2,860 cu. yds. at $39,400 2,600 45,800 Backfill— core-wall--- 5,300 cu. yds. at $0 45 $2,400 Earth fill- Dam 281,300 cu. yds. at $0 45 $126,600 Highway 39,000 cu. yds. at 50 19.500 Spillway: Excavation 24,500 cu. yds. at $100 $24,500 Reinforced concrete — Lining 2,020 cu. yds. at 16 50 33,300 Cut-offwal'.s 270cu.yds.at 15 00 4,100 Outlet: Reinforced concrete tower 120 cu. yds. at $32 75 $3,900 Trashracks 1,500 lbs. at 10 200 Excavation for pipe 670cu. vds.at 50 300 Steel pipe— 36-inch 450 feet at 13 50 6,100 Concrete pipe cover and collars 330 cu. yds .at 10 50 3,500 Backfill over pipe 340 cu. yds. at 45 200 Slide gates— 36-inch 2 at 3,000 00 6,000 Reservoir: Land and improvements $271,400 Clearing 20 acres at $30 00 600 2,400 61,900 20,200 272,000 Sub-total $609,100 Administration, engineering and contingencies, 25% 1.52,300 Interest during construction — 6"^; rate — 1-year period 46,600 TOTAL COST $808,000 VENTURA COUNTY INVESTIGATION' 239 TABLE 93 COST OF DUNSHEE RESERVOIR ON COYOTE CREEK With 120- foot Earth Fill Dam Cre.st of dam, elevation 530 feet, U. S. G. S. datum Crest of spillway, elevation 515 feet Dam: Diversion of stream — Excavation^ Open cut Tumiel Concrete — Reinforced — tunnel lining. Head-walls.. Mass — tunnel plug Capacity of reservoir, 7,100 acre-feet Capacity of spillway, lO.fiOO second-feet 2,400 cu. vds. at 2,600 cu. yds. at 1,390 cu. yds. at 110 cu. vds. at 180 cu. vds. at Excavation — Stripping Rock — toe-wall trench. 128,000 cu. yds. at 2,000 cu. yds. at Earth fill- Impervious 435,000 cu. yds. at Per\-ious 194,000 cu. yds. at Concrete-facing — Reinforced — slab Toe-wall Spillway: Excavation — Open cut Concrete — Reinforced — pa\-ing Outlet: Steel pi pe — 36-i neh Trash rack Slide gate— 3' X 3' Needle ^'alve — 36-inch... $1 50 11 50. 22 00- 20 00 12 00 $0 50 4 00 $0 40- 35- Earth dyke: Rolled fill.. Revetment- Reservoir: Land and improveaaents- Clearing Sub-totaL .---.- - . -Administration, engineering and contingencies — 25%.. Interest during construction — 6% rate — 1-year period. 14 acres at $100 00- $3,600 29,900 30,600 2,200 2,200 $64,000 8,000 $174,000 67,900 2,800 cu. vds. at 2,000 cu. yds. at 6.800 cu. yds. at 1,770 cu. yds. at $17 25 15 75 $1 50 17 75 $8 65 10 4,400 00 7,000 00 $0 40 32 $48,300 31,500 $10,200 31,400 700 ft. at 3,000 lbs. at 1 at 1 at $6,100 300 4,400 7,000 7,000 cu. yds. at 10,000 sq. ft. at $2,800 3,200 $10,000 1,400 $68,500 72,000 241,900 41,000 17,800 6,000 11,400 TOTAL COST. $539,000 134,800 41,000 $714,800 TABLE 94 DIVERSION CANAL, SANTA ANA CREEK TO DUNSHEE RESERVOIR Capacity, 200 Second-feet; Length, 1.25 Miles Right-of-way and clearing. Excavation: Dam and control works. 9,000 cu yds. rock at $1 00. 14,400 cu. yds. earth at 25. 2,330 lin. ft. concrete lining at 3 00- B.ASE COST Engineering, administration and contingencies — 25%. Interest during construction — rate 6% TOTAL COST. $9,000 3,600 7,000 $400 19,600 7,000 $27,000 7,000 1,000 $35,000 PUBLICATIONS DIVISION OF WATER RESOURCES 16—8367—8375 ( ^"H ) PUBLICATIONS OF THE DIVISION OF WATER RESOURCES DEPARTMENT OF PUBLIC WORKS STATE OF CALIFORNIA When the Department of Public Works was created in July, 1921, the State Water Commission was succeeded by the Division of Water Rights, and the Department of Engineering was succeeded by the Division of Engineer- ing and Irrigation in all duties except those pertaining to State Architect. Both the Division of Water Rights and the Division of Engineering and Irrigation functioned until August, 1929, when they were consolidated to form the Division of Water Resources. STATE WATER COMMISSION First report, State "Water Commission, March 24 to November 1, 1912. Second Report, State Water Commission, November 1, 1912, to April 1, 1914. ♦Biennial Report, State Water Commission, March 1, 1915, to December 1, 1916. Biennial Report, State Water Commission, December 1, 1916, to September 1, 1918. Biennial Report, State Water Commission, September 1, 1918, to September 1, 1920. ♦Bulletin No. 1 ♦Bulletin No. 2 — ; ♦Bulletin No. 3— ♦Bulletin No. 4— ♦Bulletin No. 5— Bulletin No. 6— Bulletin No. 7 — ♦Biennial Report, ♦Biennial Report, Biennial Report, Biennial Report, DIVISION OF WATER RIGHTS Hydrographic Investigation of San Joaquin River, 1920-1923. Kings River Investigation, Water Master's Reports, 1918-1923. Proceedings First Sacramento-San Joaquin River Problems Con- ference, 1924. Proceedings Second Sacramento-San Joaquin River Problems Con- ference, and "Water Supervisors' Report, 1924. San Gabriel Investigation — Basic Data, 1923-1926. San Gabriel Investigation — Basic Data, 1926-1928. San Gabriel Investigation — Analysis and Conclusions, 1929. Division of "^^ater Rights, 1920-1922. Division of Water Rights, 1922-1924. Division of "Water Rights, 1924-1926. Division of "VVater Rights, 1926-192S. DEPARTMENT OF ENGINEERING Cooperative Irrigation Investigations in California, 1912-1914. Irrigation Districts in California, 1887-1915. Investigations of Economic Duty of Water for Alfalfa in Sacra- mento Valley, California, 1915. Preliminary Report on Conservation and Control of Flood Waters in Coachella Valley, California, 1917. Report on the Utilization of Mohave River for Irrigation in Victor Valley, California, 1918. California Irrigation District Laws, 1919 (now obsolete). ■Use of water from Kings River, California, 1918. Flood Problems of the Calaveras River, 1919. Water Resources of Kern River and Adjacent Streams and Their Utilization, 1920. Department of Engineering, 1907-1908. Department of Engineering, 1908-1910. Department of Engineering, 1910-1912. Department of Engineering, 1912-1914. Department of Engineering, 1914-1916. Department of Engineering, 1916-1918. Department of Engineering, 1918-1920. * Reports and Bulletins out of print. Tliese may lie horrowcd tiy your lof-al lihrary from the California State tihraiT at .Sacramento, California. ♦Bulletin No. 1 — ( ♦Bulletin No. 2—] Bulletin No. 3—] ♦Bulletin No. 4 — ] ♦Bulletin No. 5—] ♦Bulletin No. 6— ( Bulletin No. 7—1 •Bulletin No. 8 — ] Bulletin No. 9—" ♦Biennial Report, ♦Biennial Report, ♦Biennial Report, ♦Biennial Report, ♦Biennial Report, ♦Biennial Report, ♦Biennial Report, ( 242) LIST OF PUBLICATIONS 243 DIVISION OF WATER RESOURCES Including Reports of the Former Division of Engineering and Irrigation *Bullt'tin Xo. 1 — California Jrrigatinn District Laws, l!i21 (m.w dl^solt-ie ) . •Bulletin No. 2 — iFormation of Irrigation Districts, Issuance of Bonds, etc., 1922. Bulletin No. 3 — Water Resources of Tulare County and Their Utilization, 1922. Bulletin No. 4 — Water Resources of California, 1923. Bulletin No. 5 — Flow in California Streams, 1923. Bulletin No. 6 — Irrigation Requirements of California Lands, 1923. ♦Bulletin No. T — California Irrigation District Laws, 1923 (now obsolete). ♦Bulletin No. S — Cost of Water to Irrigators in California, 1925. Bulletin No. 9 — Supplemental Report on Water Resources of California, 1925. ♦Bulletin No. 10 — California Irrigation District Laws, 1925 (now obsolete). Bulletin No. 11 — Ground Water Resources of Southern San Joaquin Valley, 1927. Bulletin No. 12 — Summary Report on the "Water Resources of California and a Coordinated Plan for Their Development, 1927. Bulletin No. 13 — The Development of the Upper Sacramento River, containing U. S. R. S. Cooperative Report on Iron Canyon Project, 1927. Bulletin No. ♦Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. 14 — The Control of Floods by Reservoirs, 192 S. IS — California Irrigation District Laws, 1927 (now obsolete). ♦Bulletin No. 18 — California Irrigation District Laws, 1929, Revision (now obsolete). Bulletin No. IS-B — California Irrigation District Laws, 1931, Revision. Bulletin No. 19 — Santa Ana Investigation, Flood Control and Conservation (with packet of maps), 1928. Bulletin No. 20 — Kennett Reservoir Development, an Anaylsis of Methods and Extent of Financing by Electric Power Revenue, 1929. 21 — Irrigation Districts in California, 1929. 21-A — Report on Irrigation Districts in California for the year 1929. 21-B — Report on Irrigation Districts in California for the year 1930. 21-C — Report on Irrigation Districts in California for the year 1931. ( Mimeographed. ) Bulletin No. 21-D — Report on Irrigation Districts in California for the year 1932. ( Mimeographed. ) 22 — Report on Salt Water Barrier (two volumes), 1929. 23 — Report of Sacramento-San Joaquin Water Supervisor, 1924-1928. 24 — A Proposed Major Development on American River, 1929. 25 — Report to Legislature of 1931 on State Water Plan, 1930. 26 — Sacramento River Basin, 1931. -Variation and Control of Salinity in Sacramento-San Joaquin Delta and Upper San Francisco Bay, 1931. Bulletin No. 28 — Economic Aspects of a Salt Water Barrier Below Confluence of Sacramento and San Joaquin Rivers, 1931. Bulletin No. 28-A — Industrial Survey of Upper San Francisco Bay Area, 1930. Bulletin No. 29 — San Joaquin River Basin, 1931. Bulletin No. 31 — Santa Ana River Basin, 1930. Bulletin No. 32 — South Coastal Basin, a Cooperative Symposium, lli30. Bulletin No. 33 — Rainfall Penetration and Consumptive Use of Water in Santa Ana River Valley and Coastal Plain, 1930. -Permissible Annual Charges for Irrigation Water in Upper San Joaquin Valley, 1930. -Permissible Economic Rate of Irrigation Development in Cali- fornia, 1930. -Cost of Irrigation Water in California, 1930. -Financial and General Data Pertaining to Irrigation, Reclamation and Other Public Districts in California, 1930. -Report of Kings River Water Master for the Period 1918-1930. 39 — South Coastal Basin Investigation, Records of Ground Water Levels at "^'ells, 1932. Bulletin No. 40 — South Coastal Basin Investigation, Quality of Irrigation Waters, 1933. Bulletin No. 41 — Pit River Investigation, 1933. Bulletin No. 42 — Santa Clara Investigation, 1933. Bulletin No. 34- Bulletin No. 35- Bulletin No. 36- Bullenn No. 37- Bulletin No. 38- Bulletin No. 39- * Reports and Bulletins out of print. Liliriiiv at Sarramento. California. These may l)e borrowed hy your local library from tlie California State 244 LIST OF PUBLICATIONS Bulletin No. 43 — ^Value and Cost of T^''ater for Irrigation in Coastal Plain of Southern California, 1933. '"' Bulletin No. 44 — Water Losses Under Natural Conditions from Wet Areas in Southern California, 1933. , Bulletin No. 46 — Ventura County Investigation, 1933. Biennial Report, Division of Engineering and Irrigation, 1920-1922. Biennial Report, Division of Engineering and Irrigation, 1922-1924. Biennial Report, Division of Engineering and Irrigation, 1924-1926. Biennial Report, Division of Engineering and Irrigation, 1926-1928. PAMPHLETS Act Governing Supervision of Dams in California, with Revised Rules and Regula- tions, 1933. Water Commission Act with Amendments Thereto, 1933. Rules, Regulations and Information Pertaining to Appropriation of Water in Cali- fornia, 1933. Rules and Regulations Governing the Determination of Rights to Use of Water in Accordance with the Water Commission Afct, 19 25. Tables of Discharge for Parshall Measuring Flumes, 1928. General Plans, Specifications and Bills of Material for Six and Nine Inch Parshall Measuring Flumes, 1930. COOPERATIVE AND MISCELLANEOUS REPORTS ♦Report of the Conservation Commission of California, 1912. ♦Irrigation Resources of California and Their Utilization (Bui. 254, Office of Exp. U. S. D. A.) 1913. ♦Report, State Water Problems Conference, November 25, 1916. ♦Report on Pit River Basin, April, 1915. ♦Report on Lower Pit River Project, July, 1915. ♦Report on Iron Canyon Project, 1914. ♦Report on Iron Canyon Project, California, May, 1920. ♦Sacramento Flood Control Project (Revised Plans), 1925. Report of Commission Appointed to Investigate Causes Leading to the Failure of St. Fi-ancis Dam, 1928. Report of the California Joint Federal-State Water Resources Commission, 1930. Conclusions and Recommendations of the Report of the California Irrigation and Reclamation Financing and Refinancing Commission, 1930. ♦Report of California Water Resources Commission to the Governor of California on State Water Plan, 1932. ♦Booklet of Information on California and the State Water Plan prepared for United States House of Representatives' Subcommittee on Appro- priations, 1931. ♦Bulletin on Great Central Valley Project of State Water Plan of California Prepared for United States Senate Committee on Irrigation and Reclama- tion, 1932. * Reports and Bulletins out of print. These may lie lionowed liy your IoimI liijravy from tiie California State Library at Sacramento, California. S3G7 4-34 (iOO 8375 4-34 400 l^g; 1 i> , i ■ > i rn i ^u tf j i f .^ SOUTHWEST EASTERN BASIN L 3. GEOLOGIC SECTION A-A AFTER USGS BULL 753 ^ LEVEL -500 SIMI VALLEY BASIN '^ -~-5L x_ is \ < ..Tsp\ \ Is Tm Tsp — . _ tfl y^ Tmz ./^l^jl --— ,____Qal 7mf y GEOLOGIC SECTION B-B AFTER USGS BULL 753 PIRU BASIN SIMI VALLEY BASIN GEOLOGIC SECTION C-C AFTER USGS BULL 753 STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES VENTURA -COUNTY INVESTIGATION GEOLOGIC SECTIONS HORIZONTAL SCALE SANTA PAULA BASIN WESTERN LAS POSAS BASIN PLEASANT VALLEY BASIN GEOLOGIC SECTION E-E GEOLOGIC SECTION D-D FROM USGS BULL 753 GEOLOGIC SECTION F-F VENTURA RIVER VALLEY GEOLOGIC SECTION G-G OJAI VALLEY BASIN / > I ' I ■ I 'I ' I '' I :•, 1 :. ,"^ ! " --^-^ \_^ I " , l '■ I ■' i " ^ / Av J , r> -^ " J '-.^J , --i^^:x ' " I 'T- PLATE XX.vn ^'Him^JiS-''^'^ '"II, h i ^ DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION LINES OF EQUAL CHANGE GROUND WATER TABLE FALL OF 1931 TO FALL OF 1932 IN SANTA CLARA RIVER. SIMI. LAS POSAS. SANTA ROSA VALLEYS AND OXNARD PLAIN ~T~ ^^ I I '< I I -« / / ^ /" PLATE XLV / '« / '» T" / ?a / S3 / S4 / H'T'"'-'™""""'"' .H. ^ ■"- -X- *"*"■ 'ST SS. .JSii. BBM 'v ! i 1 -? 4 \m i lUf 1«J ZIJM U.fJJ Mil i.m tm \ m.m \ i»^ ""^"nn DIVISION OF WATER RESOURCES VENTURA COUNTY INVESTIGATION IRRIGATED CROPS 1932 ! ^e / s? / se / / 3, / 3, I THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW •^ J.i AN INITIAL PINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.00 ON THE SEVENTH DAY OVERDUE. HE? 1 K96F ' SEP 12 19 5 JUN 3 1974 Book Slip-25m-7,'53(A8998s4)458 PHYSICAL SCIENCES LIBRARY Tcaz4 LIBRARY UNIVERSITY OF CALIFORNIA' DAVIS 111608 3 1175 00644 6234