' 12 I THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS p> k im STATE:^0F CALIFORNIA DEPARTMENT OF PUBLIC WORKS PUBLICATIONS OF THE DIVISION OF WATER RESOURCES EDWARD HYATT, State Engineer Reports on State Water Plan Prepared Pursuant to Chapter 832, Statutes of 1929 BULLETIN No. 33 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER IN SANTA ANA RIVER VALLEY AND COASTAL PLAIN A Cooperative Progress Report by the Division of Agricultural Engineering of the U. S. Department of Agriculture. 1930 81141 I TABLE OF CONTENTS LETTER OF TRANSMITTAL— ^^Tn ACKNOWLEDGMENT II~IIIIIIIII"IZ iV R§^^S?i'^^!J95^• STATE DEPARTMENT OP PUBLIC" WORKS 12 ?£?#?i^^r3T''sTi?S^Tfi!)^P^Ti^2"9^^ opTg^r^iIuLture::::: | ^^iillW' STATUTES OP 1929:::::::::::::::::::::::::::::::::::::::: | Part I RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER ON VALLEY FLOORS Chapter I INTRODUCTION AND SUMMARY iq Definition of terms "_:_ _:i:~I~:::::: 20 Apparent specific gravity (volume weiglit): I ~ ~ " pn Pield capacity !___ 3 iY. Consumptive use ~ :_:::::: 21 Initial fall moisture deficiency : of Acre-inches per acre pi Transpiration use : || Soil moisture percentages : ~ o? Summary :_:_ : ~ :: : ?! General description of area : : : Z :_:::::::":: 22 Chapter II METHODS AND EQUIPMENT .,. Ramfall penetration stations ~ iJ Soil moisture studies :: ::::::i:::::::::i::::~ 11 Chapter III AREAS OF NONIRRIGATED LAND___ 90 Brush -_ _ ^l Devil Canyon Shaft Plot :ii::i it Analyses of material I _ on Mechanical analyses 01 Apparent specific gravity ~ "" ,1 Artificial rain I_i:::::i:: ^Q Disposal of rainfall — soil moisture deficiency-. H Run-off IIIi: ^t Evaporation and transpiration ~ oT Season of 1927-28 :_::il H Season of 1928-29 it Season of 1929-30 ^A Muscoy plots TX Claremont Tunnel Plot I ~ ji Palmer Canyon Plot K I J^ Special plots " li Plot B2 49 Plot B3 : 50 Plot B4 51 Plot B5 ~ |1 Plot B6 ~ 51 Plot B7- Plot BS. 51 52 General stations Z ~ 51 No. 75 ~~ 52 No. 76 52 No. 104 ::::::::::::::::::::: rl Summary of disposal of rainfall on brush plots rj Grass and weeds 21 Devil Canyon Plot B ~ %1 pyie Shaft Plot II ::::i~ii::::~:::::~: 11 Special rainfall penetration stations ~ ~ cs Station A ?° Station D 59 Station E I_ " 60 Station P I_ oj Station G °i Station H :::::::::::::::::~:ii:::::::: 11 (3) 4 TABLE OF CONTENTS Chapter IV Paqb CONSUMPTIVE USE OF WATER BY NATIVE VEGETATION ALONG STREAM CHANNELS 65 Measurements on Temescal Creek 65 Supporting tank data 68 Probable limits to the losses along stream channels 73 Chapter V AREAS OP IRRIGATED LAND 75 Citrus orchards 75 Ebert plots 75 Holden Plot 76 Woodbridgc and Buchanan plots 80 Comparison of penetration of rainfall in citrus plots ; 81 Deciduous orchards 82 Walline Plot 82 Rainfall penetration tests by inspection 82 Alfalfa 85 Thomas Plot 85 Chapter VI FACTORS IN RAINFALL DISPOSAL 87 Initial soil moisture deficiency 87 Summary of plots 87 Citrus and walnut plots, Orange County 87 Run-off 91 Evaporation and transpiration losses 93 Evaporation from bare soil after rain — Ontario Plot 93 Edison Avenue Plot 94 Interception of rain by vegetation 96 Results of test No. 1 98 Summaiy of winter consumiJtive use 98 Soil drainage with no surface evapoi'ation or transpiration 99 Edison Avenue Plot 99 Evaporation from water surface 100 Part II EVAPORATION AND TRANSPIRATION LOSSES FROM MOIST AREAS Chapter I GENERAL STATEMENT 107 Introduction 107 Summary 107 Chapter II EXPERIMENTS AT SANTA ANA AND SAN BERNARDINO STATIONS 110 Meteorological conditions 110 Santa Ana Station : 114 Description of site 114 Equipment installed 114 San Bernardino Station 116 Methods vised in filling soil tanks 116 Operation of soil tanks 119 Santa Ana Station 119 San Bernardino Station 124 The water-year 125 Protecting soil tanks from rainfall 126 Results of soil tank operation 126 The Mariotte tank 128 Operation 133 Effects of temperature 134 Consumptive use of water by tules 135 Effect of oil films on evaporation 138 Chapter III PERCHED WATER TABLE IN ORANGE COUNTY 141 General discussion . 141 Surface test wells 142 Rainfall penetration 143 Appendix PRECIPITATION RECORDS 147 PUBLICATIONS OF THE DIVISION OF WATER RESOURCES 159 LIST OF TABLES Part I Table Page 1. Penetration below root zone and consumptive use of water at Devil Canyon Plot, San Bernardino 30 2. Mechanical analysis of material taken from Devil Canyon Shaft, San Bernardino, 1928 31 3. Mechanical analysis of material used in field determinations of apparent specific gravity 32 4. True specific gravity of material taken at various depths from Devil Canyon Shatt, San Bernardino 33 5. Artificial rainfall records at Devil Canyon Shaft, San Bernardino, 1928 34 6. Average moisture content at Devil Canyon Shaft, San Bernardino,, 1928 36 7. Rainfall records, 1927-:i8, Devil Canyou Shaft and Xewmark Reservoir, San Bernardino 36 8. Transpiration use of water by brush at Devil Canyon Shaft, San Bernardino, June 8 to September 7, 1928 37 9. Rainfall record, 192 8-2 9, Devil Canvon Shaft, San Bernardino 39 10. Average moisture content at Devil Canyon Shaft, San Bernardino, 1929 39 11. Transpiration use of water by brush at Devil Canyon Shaft Plot, San Bernardino; May 1 to August 1, 1929 40 12. Rainfall record, 1929-30, Devil Canyon Shaft, San Bernardino 41 13. Average moisture content at Devil Canyon Shaft, San Bernardino, 1930 41 14. Transpiration use of water by brush at Devil Canyon Shaft Plot, San Bernardino, May 15 to August 23, 1930 41 1.5. Field capacity, initial fall moisture and initial deficiency at various depths in Muscov Brush plots I and J 43 16. Disposal of rainfall at Muscov Brush Plot I, 1927 to 1930 44 17. Disposal of rainfall at Muscov Brush Plot J, 1927 to 1930 44 18. Winter evaporation-transpiration rates at Muscoy Brush Plot I, 1927-1930 — 45 10. "W'Miter evapo'-ation-transpiration rates at Muscov Brush Plot J, 1927-1929 — 45 20. Average moisture content at Claremont Tunnel Brush Plot I, 1929 and 1930__ 47 21. Field capacitv, initial fall moisture content and initial deficiency at various depths in Palmer Canyon Brush Plot K 49 22. Average moisture content at Palmer Canyon Brush Plot K 49 23. Comparison of rainfall at nine foothill stations for storm of January 5 to 15, 1930 50 24. Penetration of rain and fall deficiency in soil moisture content at seven loca- tions on the rocky brush covered fans of San Antonio, Cucamonga, Deer and Dav creeks 51 25. Results of soil sampling at General Station No. 75-brush, 1928 and 1929 52 26. Results of soil sampling at General Station No. 76-brush, 1928, 1929 and 1930 53 27. Summary of dispo.sal of rainfall on brush plots, 1927 to 1930 54 28. Summary of average winter rates of evaporation-transpiration and initial fall deficiencies in soil moisture content for brush covered areas 55 29. Average moisture content at Devil Canyon Plot B-grass and weeds, Novem- ber 3. 19'^9 to .Tanuarv 11. 1930 56 30. Initial deficiencv in soil moisture content at beginning of the rainy season, 1928 and 1929, Devil Canvon Plot B 57 31. Re.sults of soil sampling at Pyle Shaft Plot Il-grass and weeds, 1928, 1929 and 1930 - 58 32. Differences in flows of Temescal Creek at two-hour intervals past dam and bridge . 67 33. Summarv of results showing: indicated evaporation-transpiration losses at Temescal Creek, April 16 to May 27. 1929 69 34. Monthlv loss of water bv evanoratinn and transpiration from T^nks A and B at Temescal Creek and Ontario. October, 1929. to August, 1930 72 35 "U^eeklv ]o.9s of water bv evaporation and transpiration from Temescal Tula Tank A, October. 1929, to June. 1930 72 36 Monthlv tran.«niration use of water — Ebert Grove, Plot A. Mature Navel orange "trees, Julv. 1928. to .Tune, 1930 jt^——, '^^ 37. Monthlv transpiration u=e of water — Ebert Grove, Plot B. Mature Navel orangetrees, March. 19?9, to .Tune, 1930 78 38. Disposal of rainfall — Ebert Grove. Plot B. Mature Navel orange trees. Season of 1928-29 79 39. Disposal of rainfall — Ebert Grove, Plot B. Mature Navel orange trees. Season of 1929-30 "^S 40. Disnosal of rainfall — 'TVoodbridge Plot. Mature lemon trees. Season of 1929-30 80 41. Disposal of rainfall — Buchanan Plot. Mature Navel and Valencia orange trees. Season o^ 1929-30 81 42 Deficiencv of soil moisture and disposal of rainfall — ^Walline Plot. Tuscan pTng neaches. R-^a^on of 1928-29 82 43 T^sp of water — ■'W^alline Plot, Tuscan cling peaches, Ontario, 1928 82 44. Penetration of rainfall in neach and apricot orchards as determined by field :• inspection. Season of 1928-29 83 (5) b LIST OP TABLES Table Page 45. Penetration of rainfall in vineyards as determined by field inspection. Sea- son of 1928-29 83 46. Penetration of rainfall in walnut groves as determined by field inspection. Season of 1928-29 84 47. Penetration of rainfall in peach and apricot orchards as determined by field inspection. Season of 1929-30 84 48. Penetration of rainfall in vineyards as determined by field inspection. Sea- son of 1929-30 85 4 9. Penetration of rainfall in walnut groves as determined bv field inspection. Season of 1929-.Sn 1 85 50. Consumptive use of water — alfalfa plot, Thomas Ranch, Chino, 1930 86 51. Summary of initial fall moisture deficiency for various plots 88 52. Deficiency of soil moisture in citrus groves, Orange County, 1928 88 53. Deficiency of soil moisture in citrus groves, Orange County, 1929 89 54. Maximum deficiency of soil moisture under good irrigation practice on basis of root distribution for citrus. Orange County, 1928 90 55. Maximum deficiency of soil moisture under good irrigation practice on basis of root distribution for citrus. Orange County, 1929 90 56. Deficiency of soil moisture in walnut groves. Orange County 90 57. Maximum deficiency of soil moisture under good irrigation practice on basis of root distribution for walnuts. Orange County, 1928 and 1929 91 58. Rainfall run-off from Riverside Field Plot 1 — 5.28 acres of Navel oranges on Ramona loam soil 92 59. Rainfall ruji-off from Riverside Field Plot 6 — 11.8 acres of oats on Ramona loam soil 92 60. Rainfall run-off from Riverside Plot 7 — native brush — 100 square feet in plot on Ramona lo^ni soil 93 61. Rainfall run-off from Riverside Plot 8 — clean furrow plot in walnut grove — 100 square feet in plot on Ramona loam soil 93 62. Intensity of rainfall on Riverside run-off plots — table gives intensities of 0.20 inch per hour or higher , 93 63. Evaporation from bare soil after rain — Edison Avenue Plot. Season of 1928-29 96 64. Summary of average winter evaporation-transpiration rate per 30 days for brush, and grass and weed plots 98 65. Soil drainage with no surface evaporation or transpiration. Covered Plot A — Edison avenue, Ontario. 1929-30 101 66. Soil drainage with no surface evaporation or transpiration. Covered Plot B — TTfiisnn avenue, Ontario, 19.'^0 102 67. Evaporation from water surface — ^Class A Weather Bureau type of pan at Ontario, San Bernardino and Santa Ana 103 68. Evaporation from water surface — Class A Weather Bureau type of pan at C'trus Experiment Station. University of California. Riverside 103 69. "^"eeklv record of evaporation from water surface — Class A Weather Bureau type of pan at Ontario 104 Part II 1. Monthly temperatures, rainfall and miles of wind movement per month at Santa Ana and San Bernardino stations 111 2. Daily rainfall at Santa Ana Station, with totals for storms, 1929-30 112 3. Daily rainfall at San Bernardino Station, with totals for storms, 1929-30 112 4. Installation data on tanks used at Santa Ana and San Bernardino stations 121 5. Distribution cf soil moisture in Tank No. 3, September 25, 1929, Santa Ana Station 122 6. Summary showing weekly evaporation from soil and water surfaces and use of water by salt grass and tules, May, 1929, to May, 1930, in tanks at Santa Ana following page 124 7. Summary showing weekly use of water by Bermuda grass. May, 1929, to May, 1930, in tanks at San Bernardino 125 8. Summary showing monthly evaporation from soil and water surfaces and use of water by salt grass and tules, Mav, 1929, to May, 1930, in tanks at Santa Ana 127 9. Summary showing monthly evaporation from water surfaces and use of water by Bermuda grass and tules, May, 1929, to May, 1930, in tanks at San Bernardino 129 10. Difference in gage heights due to temperature, Mariotte Tank No. 4, at San Bernardino Station 135 11. Monthly use of water by tules growing in submerged soil in Tank No. 19 at Santa Ana Station 137 12. Evaporation from oil-covered water surfaces, as compared with free-water surfaces 140 13. Mean rise of perched water table in Orange County due to rainfall between December, 1929, and April, 1930 143 Appendix ' 1. Rainfall data at Santa Ana; U. S. "Weather Bureau 149 2. Rainfall data at Tustin ; U. S. Weather Bureau 150 3. Rainfall data at Corona; U. S. Weather Bureau 150 4. Rainfall data at Chino ; American Beet Sugar Company 151 5. Rainfall data at Narod ; W^est Ontario Citrus Association, C. W. Fox, observer 151 6. Rainfall data at Twenty-second street. Upland ; J. R. Johnson, observer 152 7. Rainfall data at Baseline and Hermosa avenues, Alta Loma ; L. A. Smith, observer 152 8. Rainfall data at Guasti ; Guasti Wine Company 153 I LIST OF TABLES 7 Table Page 9. Rainfall data at "Wineville ; Charles Stern and Company 153 10. Rainfall data at Riverside; U. S. Weather Bureau 154 11. Rainfall data at Etiwanda : W. F. Barnes, observer 154 12. Rainfall data at San Bernardino; U. S. Weather Bureau 155 13. Rainfall data at Redlands ; U. S. Weather Bureau 156 14. Rainfall data at mouth of San Antonio Canyon; U. S. Weather Bureau 157 15. Rainfall data at Lytle Creek; U. S. Weather Bureau 158 16. Rainfall data at Devore Ranch ; U. S. Weather Bureau 158 LIST OF PLATES Plate I II III IV V VI VII VIII IX X XI XII XIII XIV XV XVI XVII XVIII XIX XX XXI XXII XXIII XXIV XXV XXVI XXVII Part I Page General map showing rainfall penetration stations following page 20 tSoil sampling equipment 26 Devil Canyon Plot, showing brush cover and material from shaft. November, 1928 29 Variation in moisture content at Devil Canyon Plot, 1928 35 Variation in moisture content at Devil Canyon Plot, 1929 38 Variation in moisture content at Devil Canyon Plot, 1930 42 Muscoy Brush Plot J. August, 1930 43 Claremont Tunnel Plot. August, 1930. A. Cover crop. B. Soil profile 46 Palmer Canyon Brush Plot. August, 1930. A. Cover crop. B. Soil profile 48 Pyle Shaft Plot. August, 1930 57 Typical clean cultivated plot and adjacent grass and weed plot 59 Storage of rainfall in the soil. Plots A-1 and A-2, Anaheim, Union Water Company fiO Storage of rainfall in the soil, Plots D-1 and D-2, Edison avenue 61 Storage of rainfall in the soil, Plots E-1 and E-2, Braundale Acres — 62 Storage of rainfall in the soil. Plot F, Cucamonga 62 Storage of rainfall in the soil, Plots G-1 and G-2, Glen Avon Heights. 63 Storage of rainfall in the soil, Plots H-1 and H-2, Redlands 64 Temescal Creek map following page 64 Temescal Creek gaging stations. A. Control at dam showing six-inch Parshall flume and U. S. Geo- logical Survey record shelter. B. Control at bridge showing six-inch Parshall flume and recorder .shelter 66 Temescal Creek swamp tanks. A. Tank A (right) and Tank B (left), June, 1930. B. Tank B at Ontario in July, 1930 70 Flow and evaporation-transpiration losses in Temescal Creek, 1929, and rate of evaporation-transpiration compared to air temperatures at Ontario, 1930 71 Tran.spiration from citrus trees during rainy season, covered plot in Ebert Grove, February, 1929 76 Transpiration losses from Navel orange trees, Ebert Grove, 1928-1929 77 Evaporation from bare soil after rain, Ontario 94 Evaporation of rain from the soil, Edison avenue, Ontario, 1928-1929 95 Interception of rain as determined by weighing and sprinkling a lemon tree. May, 1930 07 Edison avenue soil drainage plot, August, 1929 100 Part II I Daily records of evaporation from water surfaces, maximum and mini- mum temperature."? nnd wind movement, Santa Ana Station, 1929-1930 113 ir Plan of Santa Ana Station, 1929-30 115 III Placing soil tanks at Santa Ana Station. A. Cribbing and jack forcing tanks six feet into the ground, 1928. B. Soil tanks before backfilling and timbers used in driving tanks by impact, 1929. C. Soil tanks in trench before backfilling, 1929 118 IV Soil Tanks at Santa Ana Station, 1929. A. Board fronts with doorways to buried Mariotte tanks ; soil and evaporation tanks in the foreground. B. Inner shell of soil tank showing rods supporting bottom plate. C. Outer shells of soil tanks, six feet deep 120 (8) LIST OF PLATES 9 Plate Page V Mean weekly and monthly use of water by Tanks 1 to 15, Inclusive, Santa Ana Station, 1929-1930 124 VI Mean weekly and monthly use of water by Tanks 1 to 4, inclusive, San Bernardino Station, 1929-1930 124 VII Mariotte tank connected to soil tank to maintain a constant water level in the soil and supply water evaporated or transpired, Santa Ana Station, 1929-1930 130 VIII Board front for Mariotte tank showing doorway with glass tube and meter stick inside. Santa Ana Station, 1929 132 IX Tank No. 19, showing density of tule growth amounting to 364 stems in 3.5 square feet, Santa Ana Station, 1930 136 X Tanks used in study of prevention of evaporation by oil films, Santa Ana Station. A. Three tanks used in study, 1929. B. Oil film tank showing accumulation of waxy flakes on tank surface, 1930 138 XI Map of western Orange County showing location of surface test wells, with well numbers and surface water contours for April, 1930 144 XII Effect of rainfall penetration on 1900 acres of Newhope Drainage District as measured at Manhole 26, January to June, 1930 146 LETTER OF TRANSMITTAL Mr. Edward Hyatt, State Engineer, Sacramento, California. Dear Sir: There is transmitted herewith a cooperative progress report on "Rainfall Penetration and Consumptive Use of Water in Santa Ana River Valley and Coastal Plain" (in reference to irriga- tion). This report contains a description of the methods used, plan followed, and data obtained from the investigations conducted under cooperative contract in the Santa Ana River area, dealing with (1) penetration of rain falling upon the valley floor, and consumptive use of water by crop and native plants; and (2) loss of water from moist areas. The report indicates the extent to which rain falling upon the valley floor may penetrate below the reach of plant roots and ultimately sup- plement the ground water supply. There is indicated, also, the rela- tion of rainfall to irrigation requirements and the amount of water lost through transpiration and direct evaporation in moist areas. Respectfully submitted, U.cJ M '^4^M^ Associate Chief, Division of Agricultural Engineering, U. S. Department of Agriculture. Berkeley, California, November 1, 1930. (10) ACKNOWLEDGMENT The researcli studies set forth in this bulletin were planned jointly by the cooperating agencies with advice of officials of Orange, River- side and San Bernardino counties. Paul Bailey, A. L. Sonderegger, G. S. Hinckley and W. P, Rowe, Board of Consulting Engineers for southern California, furnished valuable advice during the progress of the work. The Board of Water Commissioners of the City of San Bernardino and "William Starke, Superintendent of the San Bernardino Municipal Water Department, provided the Devil Canyon shaft and the site for the San Bernardino Experiment Station. Acknowledgment also is made of the courtesies extended by F. C. Ebert, H. C. Troxell, and Jarrett Oliver of the U. S. Geological Survey. 0. V. P. Stout of the Division of Agricultural Engineering, furnished data relative to the Mariotte Tank. k (11) ORGANIZATION STATE DEPARTMENT OF PUBLIC WORKS B. B. Meek Director Edward Hyatt State Engineer Harold Conkling Deputy State Engineer (J2) ORGANIZATION UNrTED STATES DEPARTMENT OF AGRICULTURE BUREAU OF PUBLIC ROADS DIVISION OF AGRICULTURAL ENGINEERING Cooperating in Water Resources Investigation W. W. McLaughlin Associate Chief This bulletin was prepared by Harry F. Blaney, Irrigation Engineer, C. A. Taylor, Assistant Irrigation Engineer, and A. A. Young, Assistant Irrigation Engineer. (13) CHAPTER 832, STATUTES OF 1929 An act making an appropriation for work of exploration, investigation and preliyninary plans in furtherance of a coordinated plan for the conservation, development, and utilization of the water resources of California including the Santa Ana river, Mojave river and all water resources of southern California. [I object to the item of $450,000.00 in section 1 and reduce the amount to $390,- 000.00. With this reduction I approve the bill. Dated June 17, 1920. C. C. Younq, Governor.] The people of the State of California do enact as follows: Section 1, Out of any money in the state treasury not otherwise appropriated, the sum of four hundred fifty thousand dollars, or so much thereof as may be necessary, is hereby appropriated to be expended by the state department of public works in accordance with law in conducting work of exploration, investigation and preliminary plans in furtherance of a coordinated plan for the conservation, devel- opment and utilization of the water resources of California including the Santa Ana river and its tributaries, the Mojave river and its tributaries, and all other water resources of southern California. Sec. 2. The department of public works, subject to the other provisions of this act, is empowered to expend any portion of the appropriation herein provided for the purposes of this act, in coopera- tion with the government of the United States of America or in copera- tion with political subdivisions of the State of California ; and for the purpose of such cooperation is hereby authorized to draw its claim upon said appropriation in favor of the United States of America or the appropriate agency thereof for the payment of the cost of such portion of said cooperative work as may be determined by the depart- ment of public works. Sec. 3. Upon the sale of any bonds of this state hereafter authorized to be issued to be expended for any one or more of the purposes for which any part of the appropriation herein provided may have been expended, the amount so expended from the appropriation herein provided shall be returned into the general fund of the state treasury out of the proceeds first derived from the sale of said bonds. (14) CHAPTER 656, STATUTES OF 1929 An act providing money for the study of the flood prohlems of the Santa Ana river system, the preparation of plans and specifications in connection therewith, providing for study of rainfall penetra- tion in connection therewith, and establishment and maintenance of gauging stations, jjroviding for the cooperation hy interested counties and districts, and directing the division of engineering and irriga- tion, department of puMic works, to provide for the carrying on of said work under its own direction or under the direction of the department of agricidture of the United States, and relating thereto. [I object to the item of twenty-five thousand dollars in section 1 and reduce the amount to fifteen thousand dollars. With this reduction I approve the bill. Dated : June 3, 1929. C. C. Young, Governor.] The people of the State of California do enact as follows: Section 1. The sum of twenty-five thousand dollars or so much thereof as may be necessary is hereby appropriated out of any money in the state treasury not otherwise appropriated, which said sum shall be expended in and for the study of the flood problems of the Santa Ana river system and the study of rainfall penetration in connection there- with, and for the establishment and maintenance of gauging stations upon said river system, said wo'rk to be done under the direction of the division of engineering and irrigation, department of public works, and in conjunction with the department of agriculture of the United States of America; provided, however, that such sum shall become available and be disbursed from time to time in such amounts not exceeding said sum of twenty-five thousand dollars, as shall be matched or made avail- able by any political subdivision or subdivisions within the State of California, or by the federal government, or by any other interested party, district or agency. (15) FOREWORD This report is one of a series of bulletins on the State Water Plan issued by the Division of Water Resources pursuant to provisions of Chapter 832, Statutes of 1929, directing further investigation of the water resources of California. The series includes Bulletin Nos. 25 to 36, inclusive. Bulletin No. 25, "Report to Legislature of 1931 on State Water Plan," is a summary report on the entire investigation. Prior to the studies carried out under this act, the water resources investigation had been in progress more or less continuously since 1921 under several statutory enactments. The results of the earlier work have been published as Bulletin Nos. 3, 4, 5, 6, 9, 11, 12, 13, 14, 19 and 20 of the former Division of Engineering and Irrigation, Nos. 5, 6 and 7 of the former Division of Water Rights, and Nos. 22 and 24 of the Division of Water Resources. This bulletin is one of two pertaining to investigations of the water resources of the state prepared cooperatively by the Division of Agri- cultural Engineering, United States Department of Agriculture, the University of California Agricultural Experiment Station, and the Division of Water Resources of the State Department of Public Works. Important phases of the general investigation, particularly in south- ern California, have been the estimation of the amounts of water con tributed to underground reservoirs froih direct rainfall on the valley floor, consumptive use of Avater by crops and native plants and loss of water from moist areas. This bulletin presents the results, so fai available, of cooperative studies undertaken, pursuant to provisions o: Chapter 656, Statutes of 1929, to determine quantitatively various sources of loss from and supply to the underground water in the Santa Ana Basin occurring in the valley floor. While the data presented are in the form of a progress report, it is believed that the information obtained is of sufficient value to warrant its publication at this time. It is planned to continue and extend these studies. The bulletin is in two parts. Part I deals principally with penetra- tion of rainfall and consumptive use of water and Part II with the loss of water from moist areas. I (16) PART I RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER ON VALLEY FLOORS 2—81141 CHAPTER I INTRODUCTION AND SUMMARY* In southern California an increasing demand for water from under- ground supplies for irrigation, domestic and industrial purposes has created a need for more definite and accurate information on the con- sumptive use of water by plant life on irrigated and unirrigated lands and the contributions of rainfall on the valley floors to the ground water. The irrigation water requirements of crops are dependent on the amount and distribution of rainfall. The time of the first summer irri- gation depends on the amount of soil moisture stored within the root zone at the end of the rainy season. The need for winter irriga- tion depends on whether or not the rains are sufficient to replenish the fall deficiency in soil moisture and meet the water requirements of the crops that grow during the rainy season. The annual irrigation require- ments, therefore, are of necessity interrelated with rainfall, the primary purpose of irrigation being to maintain proper soil moisture conditions for crop production. In the past, soil moisture studies related to irri- gation requirements have been confined mainly to the period between the last effective rain in the spring and the first effective rain in the fall. In this report an attempt is made to follow the soil moisture conditions throughout the year, with special emphasis on the less explored field of winter conditions. When new land is brought under irrigation, the net increased draft on the irrigation water supply depends to a certain extent on the amount of rainfall formerly consimied by the uncultivated native growth. This amount of moisture which would have been used by the natural growth must be subtracted in obtaining the net increased draft on the water supply caused by placing land under irrigation. The penetration of rainfall and consumptive use of water on uncultivated land were there- j fore studied especially with reference to the draft on the irrigation water j supply. At the request of the State Engineer of California, a cooperative irvestigation was started in December, 1927, by the Division of Agri- ciltural Engineering, Bureau of Public Eoads, U. S. Department of Agriculture, to determine the disposition of rain falling on the valley floors of the Santa Ana River area in Orange, Riverside, and San Ber- nirdino counties. The four factors that combine in disposing of rainfall are (1) surface rin-off, (2) evaporation, (3) transpiration, and (4) percolation. Under ordinary topographic and soil conditions, a part of the precipitation * Part I was prepared by Harry P. Blaney, irrigation engineer, and C. A. Taylor, aisistant irrigation engineer, under the general supervision of W. W. McLaughlin, associate chief of the Division of Agricultural Engineering, U. S. Department of Agriculture. ( 19 ) 20 DIVISION OF WATER RESOURCES runs off from the surface of the land and eventually reaches the main drainage channels. That portion retained temporarily in the top layer of the soil or intercepted by plants is returned to the atmosphere by evaporation. Of the water whicli percolates into the ground, a portion is stored in the soil within tlie root zone and subsequently is transpired by plants, Avhile 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 three factors entering into the disposition of rainfall, since all water pene- trating 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. Fortunately, in soutliern California nature has created large under- ground reservoirs by filling deep basins with porous alluvial material. These natural underground reservoirs regulate the water supply derived from erratic precipitations by accumulating and storing the water of wet years for use in dry periods. The storage capacity of underground reservoirs of this character is enormoiLS in comparison to that of artificial surface reservoirs. These underground basins are replenished by the percolation of rain falling directly upon the valley floors, seepage from streams traversing the valleys, flood waters dis- charging over alluvial fans, artificial water spreading, return waters from irrigation and in other ways. After careful consideration of several methods, it was decided to study the problem mainly from a soil moisture standpoint by taking soil samples to a depth below the root zone. Rainfall penetration sta- tions were established on predominating soil types and studies made of rainfall, run-off, transpiration, evaporation and depth of penetration. The location of these stations is shown on Plate I. This investigation is still under way and will be continued. The purpose of this progress report is to present a portion of the data col- lected to September 1, 1930, and to describe methods and procedure followed, rather than attempt to give definite conclusions based ufon the data thus far obtained. It is not intended at this time to show the relation of these basic data to the annual irrigation requirements. More detailed studies are being conducted on the water requirements of irrigated crops and will be published later. Definition of Terms. Apparent Specific Gravity (Volume Weight). — Tlie ratio of the weight of a unit volume of oven-dry soil of undisturbed structure to that of an equal volume of water under standard conditions. Field Capacity. — The amount of water retained in a previously saturated soil after the gravitational water has drained away freely. (Following an application of water to a saturation stage there is a more or less definite period during which the drainage of the water is comparativjly rapid. After this a stage is reached where the water movement becomes comparatively slow, though continuing. The moisture still retained by the soil at the time when this change in rate of movement occurs is ihe field capacity of that soil. ) I, PLATE 1 SANTA Ana Investigation GENERAL MAP Rainfall Penetration Stations 20 DIVISION OF WATER RESOURCES runs off from the surface of the land and eventually reaches the main drainage channels. That portion retained temporarily in the top layer of the soil or intercepted by plants is returned to the atmosphere by evaporation. Of the water M'liich 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 three factors entering into the disposition of rainfall, since all water pene- trating 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. Fortunately, in southern California nature has created large under- ground reservoirs by filling deep basins with porous alluvial material. These natural underground reservoirs regulate the water supply derived from erratic precipitations by accumulating and storing the water of wet years for use in dry periods. The storage capacity of underground reservoirs of this character is enormous in comparison to that of artificial surface reservoirs. These underground basins are replenished by the percolation of rain falling directly upon the valley floors, seepage from streams traversing the valleys, flood waters dis- charging over alluvial fans, artificial water spreading, return waters from irrigation and in other ways. After careful consideration of several methods, it was decided to study the problem mainly from a soil moisture standpoint by taking soil samples to a depth below the root zone. Rainfall penetration sta- tions were established on predominating soil types and studies made of rainfall, run-off, transpiration, evaporation and depth of penetration. The location of these stations is shown on Plate I. This investigation is still under way and will be continued. The purpose of this progress report is to present a portion of the data col- lected to September 1, 1930, and to describe methods and procedurie followed, rather than attempt to give definite conclusions based upon the data thus far obtained. It is not intended at this time to show the relation of these basic data to the annual irrigation requirements. More detailed studies are being conducted on the water requirements of irrigated crops and will be published later. Definition of Terms. Apparent Specific Gravity (Volume Weight). — The ratio of the wei^'ht of a unit volume of oven-dry soil of undisturbed structure to that of an equal volume of water under standard conditions. Field Capacity. — The amount of water retained in a previously saturaled soil after the gravitational water has drained away freely. (Following an application of water to a saturation stage there is a more or less definite period during whicli the drainage of the water is comparatively rapid. After this a stage is reached where the water movement becomes comparatively slow, thougli continuing. The moisture still retained by the soil at the time when this change in rate of movement occurs is ibe field capacity of that soil. ) h 1141 — pages 20-21 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 21 ('07}su)npiive Use. — The sura of water used by the vegetative growth of a given area in transpiration or building of plant tissue and that evaporated from that area. Initial Fall Moisture Deficiency. — The amount by which the actual moisture content of a given soil zone (usually the root zone) is less than tield capacity at the beginning of the rainy season. Acre-Inches Per Acre. — The amount of water, expressed in inches of depth, over the given area. (The term is usually applied to water used in irrigation and is synonymous with the term ''inches" as applied to rainfall.) Transpiration Use. — The total amount of water, within the limits of field measurements, that is drawn from the soil directly by plant root action. Soil Moisture Percentages. — This term refers to percentages of moisture in the soil, based on the weiglit of oven-dry material. Summary. 1. The results of the last three years' work on brush plots indicate that a seasonal precipitation of at least nineteen inches is necessary before any material amount of water will penetrate below the brush root zone of the valley floors. A seasonal rainfall of less than nineteen inches is usually consumed by the brush covered area before the ground water receives any increment. 2. None of the grass and weed plots under observation in 1927-28 showed any penetration below the root zones. These plots, however, were selected in locations where the soil was deep and best suited for' accurately determining the winter rates of evaporation and transpira- tion. In the 1928-29 and 1929-30 experiments, the grass and weed pl)ts in the coarser soil types showed deep penetration below the root zone. Such penetration may be expected under these conditions after fr)m ten to twelve inches of seasonal rain have fallen. When the soil Sipports a denser grass and weed cover, the consumptive use indicated is twelve to fifteen inches before deep penetration takes place. 3. In the 1929-30 season, the average penetration of rainfall below tie root zone in three citrus plots was 5.8 inches. The average rainfall a1 these three plots was seventeen inches. 4. Unirrigated deciduous orchards that were in poor condition due t( lack of care or poor soil were found to be relatively shallow rooted, wiile the more vigorous orchards and vineyards showed root activity to fnm fifteen- to eighteen-foot depths. The poorer orchards showed deep pnetration below the root zone after eleven inches of seasonal rain, wiile some of the more vigorous orchards showed capacities for more thn eighteen inches of rain without deep penetration below the root z(ie. Penetration in the winter-irrigated areas was dependent largely 01 the time and amount of irrigation. 5. Studies of the consumptive use of water along stream channels sbw that moist land growth bordering a stream channel has a marked iiiuence on the flow of the stream. There is a daily fluctuation in flow t( meet the transpiration demands of the bordering plant growth and a Sdsonal decrease in flow as the transpiration rate increases. The peak 22 DIVISION OF WATER RESOURCES demand of transpiration on the water of a stream may be expected in July and August. Air temperature is shown to be a direct indicator of the transpiration rate and hence of the effect of transpiration on stream flow. High temperatures cause extremely high rates of transpiration and correspondingly low stream flows. 6. During the winters of 1927-28, 1928-29 and 1929-30 there was no measurable run-off from undisturbed recent alluvial soil with native brush cover on the valley floor. Certain cropped areas, particularly in the Riverside district, showed noticeable run-off. It is indicated that, in the Riverside area of ancient alluvial soil type, the principal contri- bution of rainfall on the valley floor to the ground water comes from surface run-off. The average seasonal rainfall of the Riverside area is too low to cause any direct penetration below the root zone, except possibly in heavily irrigated citrus areas. General Description of Area.* The watershed of Santa Ana River has a total length of 100 miles and drains 2050 square miles. Of this area, 1196 square miles are mountains, foothills and isolated hills and 854 square miles are main valley floor. Thus, 42 per cent of the entire watershed is in gravel, sands and silts, generally water absorbing and water bearing. Four- fifths of the habitable area of some 1000 square miles is about equally divided between San Bernardino and Orange counties. Except for a small area in Los Angeles County, the remaining portion lies in River- side County. Of the total habitable area, 342,700 acres are now under irrigation; 25,282 acres are in domestic use; 21,218 acres are in river beds and waste lands, and about 250,800 acres are usable in the future. The rate of increase of domestic and irrigation area for the historic period is 8000 acres per year, and for the last eight j'ears, apparently 21,000 acres per year. The assessed A'^aluation of the habitable area is $263,000,000. "Within it are operating 78 water organizations with a total service area of 191,500 acres, some with use dating back half a century. In addition 207,100 acres are occupied by individuals not so organized. Santa Ana Valley consists of a series of basins, mesas and hil.s. The basins are filled with detritus brought down from the precipitois mountains by the sudden violent floods of the region. They are separated, one from the other, by hills and mountain ranges or ly underground barriers, such as Bunker Hill Dike, crossing the valley between San Bernardino and Colton. Upper Basin is defined by Bunker Hill Dike. It could be divided into East Upper, L^'tle Creek and Yucaipa-Beaumont subbasiis. Jurupa Basin might be divided into Colton and Riverside mesis. Cucamonga Basin could be divided into Upper and Chino and these could be even further subdivided. These subdivisions are suggested by changes in character of valley fill which create changes in water conditions. Temescal Basin is not of great effect in its regulation of or contribution to the underground water supply, and no notation is made of possible subdivisions. Lower Basin or coastal plain has m ♦Abstracted in part from Bulletin No. 19 (1929), "Santa Ana Investigations," published by former Division of Engineering and Irrigation, State Department of Public Works. RAINFALL. PENETRATION AND CONSUMPTIVE USE OF WATER 23 upper percolating area and a lower nonpercolating area. The most definite division between basins is the mountain range separating the coastal plain from the remainder. Santa Ana River (plus Mill Creek) discharges 43 per cent of the total surface mountain run-off. Even with this concentration, water flows from the mountains to the ocean only during or a short time after a heavy rain. In all the remainder of the time the stream is absorbed in the porous detritus across which it flows. "Water percolates to the underground water plane and travels slowly in the direction of the flow of the surface stream until a barrier, either underground or surface, pushes it to the surface as rising water. Below the barrier another basin is crossed, percolation takes place and again the under- flow becomes rising water at the next barrier. On Santa Ana River, the first percolating area in Upper Basin begins at the mouth of the canyon and extends to a point seven miles below the mountains where Bunker Hill Dike begins to make its pres- ence felt and where water is forced to the surface for a distance of six miles. Then comes another percolating area seven miles long in Jurupa Basin. Then above Riverside water is again brought to the surface and this increases in amount for eighteen miles until it enters the lower Santa Ana Canyon, through the upper third of which it remains fairly constant but below which point it commences to show a decrease. Seventeen miles of the coastal plain ending at a point near Santa Ana comprises the third percolating area. The region be- tween that area and the ocean formerly must have been an area of rising water, but the present diminished pressures no longer cause rising water. However, the surface water plane is perched on impervious strata, thus preventing percolation. The percolating areas in the Upper Basin, in Colton subbasin and in the coastal plain are the important ones. These basins of vast unconsolidated gravel fills constitute reservoirs from which most of the water supplies of the region are drawn by means of pumps. They are supplied by percolation from streams that Cross them, by percolation from rain on the valley floor itself and by percolation from irrigation. They absorb the heavy flows and rains of the wet years and hold them for the dry years. The characteristic of the climate is the large annual and cyclic variation in precipitation and run-off, and this is ironed out and equated by these underground reservoirs. Without them the economic development of the region would have been impossible. This may be inferred from the fact that 90 per cent of the water supplies are derived from them either by 1)umps or by gravity diversions of rising water, due to and regulated ly them, and from the fact that only 10 per cent of the mountain lun-off escapes into the ocean because of their absorptive and retentive cualities. Above present water levels, it is estimated 1,500,000 acre- leet of water have been stored in them at the highest level of historical limes and through the action of nature alone. A conservation program ■"vill adopt nature's method of storage and seek to make it more (•fficient. 24 DIVISION OF WATER RESOURCES CHAPTER II METHODS AND EQUIPMENT Rainfall Penetration Stations. With a view to making an intensive study of rainfall penetration, a large number of stations have been established on predominating soil types in Orange, Riverside and San Bernardino counties. The major- ity of these stations, both on irrigated and nonirrigated tracts, are located at points where the ground water is so far beloAV the surface that capillary action will have no influence on the moisture content of the soil studied. A few of the stations, however, are located where depths to ground water are approximately fifteen feet. Ten stations are especially equipped for intensive work, and measurements of rain- fall, surface run-off, soil moisture deficiency, evaporation, transpiration and depth of penetration are made at these stations. Soil moisture conditions of the valley floor tracts usually can be studied through the aid of standard soil sampling tubes, and the storage of rain water in the soil and the downward percolation of the water thus determined. The alluvial fans or deltas occurring at points where drainage channels debouche from the mountains, however, are full of gravel and boulders which make the use of soil tubes impracticable, and where these conditions prevail shafts have been sunk to deptlis below the root zones. From these shafts tunnels have been driven laterally where desired and soil samples are taken from the sides of the shafts and tunnels. At one station of this kind near Devil Canyon, north of San Bernardino, artificial rain was applied during the 1927-28 and 1928-29 seasons and the downward movement of water observe^! in tunnels twelve and twenty feet, respectively, below the ground sur- face. A part of the surface run-off from the valley floors maj'- be termed local as it flows directly into depressions and then percolates into tha ground without reaching the main surface streams. The method of measuring local surface run-off on uncultivated land with native vegetation is to collect the run-off of small areas of 100 square feet and measure it volumetrically. Measurements of run-o from agricultural areas are made by installing Parshall flumes witl' recorders in drainage ditches. Areas of from two to twenty acres arc used in the plots. Records of rainfall intensity are kept by recording rain gages in connection with these tests. The direct penetration, as well as the surface run-off of any one season's rainfall, depends on the initial moisture conditions at th(^ beginning of the rainy season and the amount of evaporation and tran- spiration occurring during that season. These factors vary with the cover, but the area under consideration can be classified according to crops grown. Citrus trees are shallow-rooted and cause a small initial deficiency of soil moisture in the fall, but vines, deciduous trees and RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 25 native brush are deep-rooted and use the soil moisture to greater depths, thus causing 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 tran- spiration losses. With these factors known, the rainfall penetrating below the root zone can be calculated. Soil Moisture Studies. Since a large part of the rainfall entering the soil is lost by evapora- tion and transpiration, field plots having either cultivated crops or native vegetation are being studied intensively throughout the year to determine such losses. The improved soil tube* is used for obtaining soil samples for moisture determination. Soil samples are taken in one-foot sections to depths of from twelve to eighteen feet, reaching soil conditions well below the major root zone of most native and crop plants. The drying of the samples is done in an electric oven operated at 110 degrees Centigrade. In general, standard laboratory practices are used in determining the moisture content. A great number of soil samples must be taken in this work, often to depths of about eighteen feet. The work is greatly expedited by using an air hammer to drive the soil tube and a jack to withdraw it from the soil. Both the applications of the air hammer and jack were developed in connection with this investigation. The equipment is shown in Plate II and consists of a compressed air unit, soil tube and soil tube jack. The compressed air unit includes a compressor unit mounted on a truck, a light air hammer and a 100-foot length of one-half-inch rubber hose. The air hammer t for driving the tubes is of the clay-spader type and requires 40 cubic feet of air per minute at an operating pressure of 100 pounds per square inch. At this pressure, the hammer delivers about 2250 blows per minute, each blow striking with a force of sixteen foot pounds. The air supply for this unit is furnished by a duplex compressor with direct coupled gas engine drive, equipped with a self- starter. The soil tubes used range from 5.5 to 25 feet in length and consist of sixteen-gage seamless steel tubing fitted with a suitable driving head and point. The cutting point is made of case hardened nickel steel and has a choke bore so that the soil core slides up inside the tube without serious attendant friction. For the purpose of pulling the soil tubes from the ground a new type of jack:j: was perfected. The jack is light and simply made, and is very eifective in its operation. It is shown in the foreground of Plate II. Depths of 25 feet are practicable with the present equipment. Use of the apparatus is found impracticable in soil containing stones of diameters greater than two inches. Also the soil tube is not suited for * An improved soil-sampling tube, by F. J. Veihmeyer, Soil Science ; Vol. XXVII, No. 2 February, 19 29. t "An Efficient Soil Tube .Tack," by C. A. Taylor and H. F. Blaney, Soil Science ; Vol. XXVII, No. 5, May, 1929. t "Soil Sampling With a Compressed Air Unit," by H. F. Blaney and C. A. Taylor, Soil Science; Vol. XXXI, No. 1, January, 1931. 26 DIVISION OF WATER RESOURCES use in heavy clays that are wet enough to become plastic, as the core sticks to the walls of the tubing. Most of the valley floor area can be sampled with these tools, but the high alluvial fans are full of coarse rocks and boulders and dug shafts and tunnels must be resorted to. When the soil is very rocky, it is necessary to take large portions of the material in order to get representative samples. Accordingly, when it is necessary to resort to dug pits, 4000 gram samples are taken of the material as it occurs in place, without selection as to size of PLATE II I SOIL SAMPLING EQUIPMENT particles. All samples are weighed to the nearest one-tenth of a gram and oven-dried at 110 degrees Centigrade. After drying, the rocky samples are screened in a mechanical shaker to a screen with two millimeter openings. All material retained on the two millimeter screen is classed as rock. Moisture content then is computed from two f RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 27 bases: one, the oven-dry weight of the entire sample; the other, the oven-dry weight of the soil in the sample with all particles above two millimeters in diameter excluded. Wlien converting the percentage of moisture in the soil to equivalent depth of water in inches, it also is of value to have two bases for the determination of the apparent specific gravity. Accordingly, samples are obtained by cutting out cores of from 0.5 to 1.5 cubic feet of material as it occurs in place. The entire core is oven-dried and the apparent specific gravity of the natural material obtained. The entire sample then is screened and a second apparent specific gravity determined, based on the weight of the soil particles below two milli- meters in diameter as they occur in place in the field. In the second case, the rocks are regarded as space filler only and the moisture is considered as being held by the soil. This assumption that all of the moisture is held by the soil and none by the rock content is not strictly correct, especially when the moisture content of the material is near field capacity. However, in the conversion from moisture percentage to depth in inches the effect of excluding the rock in the calculations is merely to reduce the value of the apparent specific gravity and increase the percentage of moisture correspondingly. The equations are : D = PVd ^ Ps Vs d 100 100 where D is the equivalent depth of water in the soil, in inches ; d the depth of the soil sample considered, in inches; P the percentage of moisture in the soil based on the oven-dry weight of the entire sample ; V the apparent specific gravity of the material in place ; Ps the percentage of moisture based on the oven-dry weight of the soil in the sample with rock excluded ; Vs the apparent specific gravity of the soil content in place with the rock excluded. The advantage of using the relation on the screened basis lies in the fact that smaller samples may be used for regular sampling after the relationship is established for a particular plot. When large samples are taken and both methods used, a double check is obtained. In the intensive studies in orchards, seventeen holes are usually put down within a square of four trees and samples taken at two-week intervals. For an absolute check on the winter transpiration by citrus, a covered plot was established in one grove. A tent was placed on a frame under the tree branches in a square of four trees so that the soil was protected from rain within the square and to a distance of eight feet beyond each side of the square. Soil moisture records could then be kept without the interference of frequent rains. A record of soil moisture extraction was kept on this plot throughout the calendar year. In order to determine definitely what happens to the soil moisture below the root zone, two plots have been established on typical soil types. "Water was applied over a 20-foot square in sufficient amount to wet the soil to a depth of at least eighteen feet. A twelve-foot 28 DIVISION OF WATER RESOURCES square in the center of this plot then was boarded over and sealed with roofinof paper. Boards were extended one foot into the soil around the edge of the sealed area. The whole 20-foot plot then was roofed over with corrugated iron to protect the plot from rain. The ground is kept clear of vegetation for a distance of 30 feet around the plot and a trench five feet deep dug around the cleared area to guard against interference from roots. Soil samples are taken in foot sec- tions, to a depth of eighteen feet at frequent intervals in the sealed area. Holes are bored through the roof and sealed again after the samples are obtained. It is intended that this experiment shall con- tinue for at least two years, or longer if results indicate a continued drainage or loss of soil moisture. Evaporation from the soil has been carefully measured after each rainstorm throughout the season. The method followed was to select an area of deep dry soil in the fall of the year and then keep all plant growth cleared off throughout the rainy season. Trenches were dug to obtain the wetted outline of rainfall penetration and samples were taken for moisture content. Evaporation losses could be computed from these data. The final summation of the penetration of rainfall to the ground water is made after values have been established for the aforemen- tioned factors, namely, the run-off, the initial fall deficiency of soil moisture for each crop, the transpiration requirements of each crop and the evaporation losses. RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 29 CHAPTER III AREAS OF NONIRRIGATED LAND BRUSH Devil Canyon Shaft Plot. In the latter part of February, 1928, certain investigations were started in cooperation with the Municipal Water Department of the city of San Bernardino to study the penetration of rainfall below the root zone, the storage in the soil of rain water and the consumptive use of water by brush on the valley floor. PLATE III DEVIL CANYON PLOT, SHOWING BRUSH COVER AND MATERIAL FROM SHAFT. NOVEMBER, 1928. The board of water commissioners of the San Bernardino Municipal "Water Department furnished funds for building a shaft and tunnels in the gravel area of the valley floor south of Devil Canyon. Under the supervision of William Starke, superintendent of the San Bernar- dino Water Department, a shaft 26 feet deep and two 20-foot tunnels, one running north twelve feet below the ground surface and the other 30 DIVISION OF WATER RESOURCES running west at the 20-foot level, were excavated. Two types of col- lector pans were placed in the roofs of the tunnels to intercept rain water and on April 20, 1928, an overhead sprinkler system was installed and in 1928 and 1929 artificial rain was applied. When the shaft was dug, the native brush cover on the experiment plot, mainly chamisal, sage, wild olive, squaw berry, cactus and yucca, was moderately heavy in comparison with the general valley floor cover. Plate III shows the brush cover as left permanently in its natural con- dition and the material from the shaft so placed as not to interfere with rainfall penetration. Observation made when the shaft was dug indicated a depth of sixteen feet of root activity for the brush present. This has been con- firmed by the results of soil sampling obtained during the past three years. Some dead roots were found at eighteen feet. The brush has not been burned within 25 years. During the last three seasons, the downward movement of water was observed in the tunnels. The square collector pans intercepted part of the moisture moving downward through tlie soil. However, the amount was not a quantitative measure of the deep penetration as shown from soil sampling, but satisfactory records were kept of the moisture con- tent of the soil by excavating into the sides of the tunnels at various levels and taking samples of the material. Samples of the soil above the tunnels were taken in foot sections with standard soil tubes. From these data the penetration of rain below the root zone and the consump- tive use of water by brush were computed. A summary of the results of each season, 1927-28, 1928-29 and 1929-30, is given in Table 1. Other brush plots are being studied and the investigation is not complete. However, the results indicate the proportion of rain penetrating below the root zone is largely dependent on the magnitude and seasonal distribution of the rain storms. TABLE 1 PENETRATION BELOW ROOT ZONE AND CONSUMPTIVE USE OF WATER AT DEVIL CANYON PLOT, SAN BERNARDINO Natural rainfall in inches Artificial rainfall in inches Total rainfall in inches Deep penetration below root zone Evapora- tion and transpira- tion in inches Season From natural rain in inches Frorn artificial rain in inches Total penetra- tion in inches 1927-28 17.67 16.33 20.90 '14 33 8.49 None 32.00 24.82 20.90 None None 1.8 5.0 6.0 None ■5.0 6.0 1.8 27.0 1928-29 18.8 1929-30 19.1 ' The artificial rainfall was applied as given in Table 5, but usually most of the natural rainfall occurs before April 16. If the 14.33 inches of artificial rain had been applied before April 15, undoubtedly ten inches of rain or more would have penetrated below the root zone instead of five inches as given. Analyses of Material. — During the construction of the shaft and tun- nels, 10,000-gram samples of material were taken from each foot section of the shaft and at typical locations in the tunnels. Smaller samples (600-gram) of the finer material, from which the coarser rocks had been RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 31 excluded, also were collected. The samples were oven-dried at 110 degrees Centigrade for moisture content determination, and specific gravity determinations and mechanical analyses were made. The mois- ture content of the material showed that the depth of rainfall penetra- tion at the time of digging the shaft averaged eight and one-half feet in the shaft and eleven feet in the north tunnel. Mechanical Analyses. — The following method was used in making the mechanical analyses: The samples were oven-dried and in each determination the entire sample (about 10,000 grams) was screened down to the No. 4 sieve inclusive (Tyler standard). A 500-gram sample was then selected by twice quartering the part of the sample which passed the No. 4 sieve. This 500-gram sample then was used for sieves Nos. 8 to 200 inclusive. The values given are expressed as percentages of the entire weight of the sample. The analyses were made in a mechanical shaker and sieved to the point of practical refusal. The results are given in Table 2. TABLE 2 MECHANICAL ANALYSIS OF MATERIAL TAKEN FROM DEVIL CANYON SHAFT, SAN BERNARDINO, 1928 Per cent of material retainec on screens Per Depth of sample in feet of following sizes cent of material 3 1.50 .742 .371 No. No. No. No. No. No. No. passing screen inch inch inch inch 4 8 14 28 48 100 200 No. 200 1 6 5 3 4 6 10 17 21 14 14 2.. . 18 7 8 5 18 19 9 4 13 11 8 5 11 7 9 5 7 6 8 7 8 9 10 11 9 15 14 17 8 18 16 21 5 6 12 14 2 1 4 11 3 1 4 1 4- 6. 2 6-8 6 18 12 8 8 6 10 13 12 5 1 1 8-10 5 5 13 14 11 17 9 11 11 19 14 9 7 12 8 7 8 8 7 8 9 6 7 13 13 8 11 15 16 11 12 10 14 9 9 5 7 3 6 2 2 1 2 1 10-12 2 12-14 . 2 14-16 2 16-18 10 3 6 7 16 5 10 5 9 6 7 14 10 23 12 21 11 11 6 3 2 1 18-20 1 20-22.. 15 11 12 13 19 11 13 12 9 8 10 8 5 7 7 7 10 9 10 11 11 14 10 12 10 if 3 2 5 2 22-24 2 24-26 4 Apparent Specific Gravity. — When the shaft was dug, samples of the material excavated were taken at one-foot intervals to the depth of 26 feet for apparent specific gravity determination. These were made by rodding the oven-dried material into a cylinder six inches in diameter and six inches deep. The cylinder was filled by thirds and each third was rodded 25 times. The weight of the material required to fill the cylinder divided by the measured volume of the cjdinder gives the apparent specific gravity (volume weight). This method was modified somewhat when a sample contained material larger than three inches in diamenter. The volume of the large rocks then was computed separ- ately and corrections made on the cylinder determinations. The aver- age apparent specific gravity from the surface to a depth of two feet was 1.76 ; from two to six feet, 2.02 ; and from six to eighteen feet, 2.04. Detailed results are as follows : 32 DIVISION OP WATER RESOURCES Depth in feet Apparent specific gravity Depth in feet Apparent specific gravity Depth in feet Apparent specific gravity 0-1 1.75 1.77 2.04 1.99 2 02 6- 8 2.06 2.08 1 99 2.08 2.13 16-18 1.87 1-2 8-10 18-20 2.13 2-3 10-12 20-22 2.07 3-4 12-14 22-24.... --- 2.11 4-6 14-16 . 24-26 2 00 Field determinations were made of apparent specific gravity on the undisturbed soil for the purpose of comparison with those made by laboratory method. The field determinations were made by collecting all the material from a hole ai)proximately six inches in diameter and eight iiu'hes deej), and determining the volume of the liole from the amount of cold molasses required for filling it. The results are as follows : Depth in feet Apparent specific gravity Laboratory Field Difference 1 1.78 1.76 1.70 2.15 1.62 1.67 1.78 2.20 -f-.16 4 -I-.09 18 — .08 26 — .05 A mechanical analysis of samples used is shown in Table 3. The true specific gravities of material taken from the shaft from surface to 26 feet are given in Table 4. TABLE 3 MECHANICAL ANALYSIS OF MATERIAL USED IN FIELD DETERMINATIONS OF APPARENT SPECIFIC GRAVITY Depth of sample in feet Per cent of material retained on screens of following sizes No. 200 Per cent of material 3 inch 1.50 inch .742 inch .371 inch No. 4 No. 8 No. 14 No. 28 No. 48 No. 100 passmg screen No. 200 1 . 31 2 16 5 5 3 10 3 4 2 8 3 5 f 2 4 8 5 5 6 15 5 9 10 29 7 20 17 24 6 23 23 10 3 14 14 3 1 14 4 18 26 12 1 1 RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 33 TABLE 4 TRUE SPECIFIC GRAVITY OF MATERIAL TAKEN AT VARIOUS DEPTHS FROM DEVIL CANYON SHAFT, SAN BERNARDINO Depth of sample in feet 0- 1. 1- 2_ 2- 3. 3- 4- 4- 6. 6- 8_ 8-10. 10-1 2 _ Average- Specific gravity' 2.67 2.66 2.68 2.66 2.68 2.67 2.67 2.67 Depth of sample in feet 12-14 14-16- 2.67 2.66 16-18 2.66 18-20 2.66 20-22 .. 2.67 22-24 2.66 24-26 2.67 Specific gravity' ' The true specific gravities were determined by finding the volume of kerosene displaced by 58 grams of the sample. Artificial Bain. — Artificial rain was supplied by using sprinklers of the Campbell type set in a group equidistant from the ends of the two tunnels. No measurable wind blew during any of the applications so that reasonably uniform amounts were applied over the tunnels and to at least eight feet beyond the end of each tunnel. Much of the variation shown in the rain gage readings was due to the intercep- tion of rain by the brush. Applications were made between 6 p.m. and midnight as this was the time of least wind and evaporation was lowest. The intensity of application varied from 0.75 inch to 1.25 inches per hour. No standing water was observed at any time during the runs in the natural, undisturbed brush area. Around the shaft where the ground was tramped down, small pools up to a foot in diameter formed after 40 minutes of application at the rate of 1.25 inches per hour, but no lateral surface movement occurred from these pools at the end of one hour. The pools disappeared at the end of fifteen min- utes after the rate was cut to one inch per hour. The air temperature in the sprinkled area varied from 45 to 60 degrees Fahrenheit during the artificial rain storms. In 1928, records were kept of the evaporation b}^ means of a standard U. S. Weather Bureau pan located 90 feet from sprinklers. The loss of water by evaporation during each artificial rain was as follows : April 24, 0.03 inch; April 28, 0.04 inch; May 5, 0.05 inch; and May 23, 0.05 inch. The artificial rainfall records for 1928 are given in Table 5. 3—81141 DIVISION OF WATER RESOURCES TABLE 5 ARTIFICIAL RAINFALL RECORDS AT DEVIL CANYON SHAFT, SAN BERNARDINO, 1928 Gage No. April 24 April 28 May 5 May 23 Location In inches In inches In inches In i nches 1 2 3 4 5 6 7 4.1 3.6 4.3 5.1 4.2 4.5 3.3 2.6 3.0 3.2 2.9 3.2 3.5 3.0 3.7 2.9 3.0 3.6 4.3 4.4 4.4 4.5 4.4 3.0 3.1 3.6 3.6 4.16 2.97 3.27 4.17 Location Gage No. In inches In inches In inches In inches 1 3 4 5 6 7 8 9 10 4.2 2.9 3.0 2.8 3.0 3.0 2.5 3,3 2.8 2.4 2.6 2.0 3.0 2.3 2.9 3.2 5.3 3.4 3.7 3.1 3.6 4.2 4.0 4.1 3.9 3.5 3.5 4.2 4.1 4.5 3.9 4.4 4,6 3.7 3.8 4.1 3.83 2.83 3.25 4.17 4.00 2.90 3.26 4.17 Total 14.33 Disposal of Rainfall — Soil Moisture Deficiency. — Soil sampling done during the last three years indicates brush extracts moisture from the soil after wilting coefficient has been reached. The soil is classified as Hanford gravelly sandy loam and has a field capacity of about six per cent. The deficiency of moisture at the beginning of the rainy season is about one inch per foot in the top two feet of soil and three- fourths inch per foot at a depth of from two to sixteen feet. On this basis the moisture deficiency is twelve and one-half inches for a root zone of sixteen feet, eleven inches for fourteen feet, nine and one-half inches for twelve feet and eight inches for ten feet. Run-off. — At six different times artificial rain was applied to the plot at the rate of from 1.0 to 1.25 inches per hour for periods of from three to five hours. No run-off occurred and pools did not form until the rate reached 1.25 inches per hour. The intensities of natural rainfall during the 1927-28, 1928-29 and 1929-30 seasons were not suf- ficient to cause run-off at any time. Evaporation and Transpiration. — It is difficult to determine the con- sumptive use of water by plants during the winter months owing to the irregularity of rainfall, but at the end of the rainy season the transpiration use of water may readily be determined by soil moisture observations. Experimennts indicate that the average evaporation loss during each storm probably does not exceed 0.5 inch. Season of 1927-28.— l^he total rainfall to February 21, 1928, at the shaft was 12.84 inches, of which 4.92 inches were stored in the top ten feet of soil, leaviiig 7.92 inches to be accounted for by evapora- tion loss and use of water by brush. i RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 35 Previous to the first application of artificial rain on April 24, 16.54 inches of natural rain had fallen. The amount of moisture stored in the soil was about six inches and the remainder of the 16.54 inches of rain, about 10.5 inches, was lost by evaporation and transpiration. From April 24 to May 23, 15.46 inches of artificial and natural rain fell on the plot. About 6.5 inches of this amount was required to make up the deficiency of soil moisture in the root zone. The consumptive use of water during this period was estimated at four inches. On this basis, five inches penetrated below the root zone. Thus, out of a total of 32 inches of natural and artificial rain during the 1927-28 season, 27 inches were lost by evaporation and transpiration. The results of the 1928-29 and 1929-30 seasons indicate that had all of the natural and artificial rain of the 1927-28 season occurred before the middle of April, as it usually does, at least five inches more of rain would have penetrated below the root zone. The average soil moisture records are shown in Table 6 for 0-2 feet, and 2-6 feet. North Tunnel and West Tunnel. The rainfall data are given in Table 7. The transpiration use of water by brush during the summer was computed and is shown in Table 8. Plate IV shows the variation in moisture content at various depths. PLATE IV 8 M M 1 1 1 1 1 ^ TO 2-FE.ET IN DEPTH / 4 \ n / 4 / -~a ^ / N>. ^ .^ / 8 — — f» ^ V 2 TO 6- FEET IN DEPTH / H b^ s N — 8 r " n ■■ 13- FOOT DEPT i /, N( RTf TUNNtL r " _ / ■" ~~r 8 — " 20-FOOT DEPTI- --= ^ - /, •* tST TUNNtL ^ ~ -°' — 1 — •o — -° — n CC 1 { I 1 1 1 RAINFALL BY STORMS pStorm total 1 / i _] ^ . J L. i f i J J Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. VARIATION IN MOISTURE CONTENT AT DEVIL CANYON PLOT, 1928. 30 DIVISION OP WATER RESOURCES TABLE 6 AVERAGE MOISTURE CONTENT AT DEVIL CANYON SHAFT, SAN BERNARDINO, 1928 Dates of sampling Average moisture content of soil 0-2 feet 2-6 feet North tunnel (13-foot level) West tunnel (20-foot level) March 3 March 7 April 24 April 25 April 28 May 5 May 7 May 16 May 23 June 8 - June 20 July 5 July 19 August 9 September 7-. October 3 November 6.. December 12. December 14. In per cent In per cent In per cent 4.5 7.7 6.7 9.0 0.3 5.3 4.2 2.8 1.9 1.6 1.4 1.4 2.3 8.1 6.9 8.4 7.1 9.7 6.7 6.2 5.9 4.5 3.0 2.3 1.8 1.9 1.9 2.0 1.2 1.4 2.8 5.0 5.9 6.2 5,3 4.7 4.3 3.1 2.2 1.8 1.8 In per cent 3.7 3.1 3.4 5.7 6.9 5.3 5.6 6 3 6.0 5.7 6.6 6.6 6.4 TABLE 7 RAINFALL RECORDS, 1927-28, DEVIL CANYON SHAFT AND NEWMARK RESERVOIR, SAN BERNARDINO Date 1927— October 26-November 1. November 6 November 10-13 December 10-14 December 25-29 1928— January 15-16. February 3-5.. March 2-6.... March 13 March 23-27... April3 May 8-9 May 17. Artificial rainfall- April 24 April 28 May 6 May 23 Total. At mouth of Devil Canyon in inches 4.71 .09 .99 2.62 .90 0.76 3.51 1.06 .25 1.76 1.50 1.27 T At Newmark Reservoir in inches 3.56 .05 .78 1.90 1.20 1.08 3.51 1.04 .21 .90 1.05 1.11 .05 At Devil Canyon shaft in inches 4.14 .07 2.26 1.06 0.92 3.51 1.05 .23 1.12 1.30 1.09 .04 4.00 2.90 3.26 4.17 32 00 I RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 37 TABLE 8 TRANSPIRATION USE OF WATER BY BRUSH AT DEVIL CANYON SHAFT, SAN BERNARDINO June 8 to September 7, 1928 Period 1928— June 8-June 20 June 8- June 20 June8-June20 June 8- June 20 June20-July 19 June20-July 19 June20-July 19 June20-July 19 July 19-August9 July 19- August 9 July 19- August 9 July 19- August 9 August 9-September 7 August 9-September 7 August 9-September 7 August 9-September 7 June 8-September 7. . June 8-September 7-. June 8-September 7. . June 8-September 7, . Number of days Depth in feet 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 Use of water For period Zone In inches 0.46 .22 .75 1.43 0.97 2,13 1.82 4.92 0.13 .52 2.19 2.84 0.08 .37 1.64 2.09 1.64 3.24 6.40 11.28 Per foot In inches 0.23 .06 Rate per 30 days In inches 1.15 .55 1.88 3.57 0.49 1.00 .53 2.20 .18 1.88 5.09 0.07 0.19 .13 .74 .22 3.13 4.06 0.04 .08 .09 .38 .16 1.70 2.16 82 .81 .64 Season 1928-29.— ^oil sampling during 1928 indicated that the field capacity of soil was about six per cent. In the fall of 1928 the top two feet of soil reached a moisture content of 1.4 per cent, showing an initial deficiency of soil moisture of about one inch per foot of soil. From two to sixteen feet the moisture content averaged 1.8 per cent, showing a deficiency of about 0.75 inch per foot. On this basis the total moisture deficiency within the root zone, or top sixteen feet of soil, was 12.50 inches, and for the top ten feet, eight inches. On April 1, a pit was dug to the depth of twelve feet about fifteen feet north of the plot. The total rainfall to that date had been 13.76 inches and it had penetrated to a depth of ten feet. Thus eight inches of rain was stored in the soil and 5.76 inches lost by evaporation and transpiration, as no run-off occurred. On April 4 and 5, 2.16 inches of rain fell. On April 6, 3.26 inches of artificial rain were applied, followed by 5.23 inches on April 8. The water was applied at night with overhead sprinklers at a rate of one inch per hour. There was no run-off. About 4.5 inches of this 10.65- inch storm were required to bring the remaining six feet of soil within the root zone (ten to sixteen feet) up to field capacity, leaving 6.15 inches to penetrate below the sixteen-foot level or root zone. The field capacity of the soil below the root zone is about six per cent, or 1.09 inches per foot of soil. The average moisture content of the soil at the 20-foot level from April 15 to 17, was 13.15 per cent, or 2.40 inches per foot. Thus, when the soil drained to field capacity, 1.31 inches per foot would have passed below the root zone. Soil sampling indicated this occurred in the soil mass from sixteen to 20 feet. On 38 DIVISION OF WATER RESOURCES this basis the four-foot section of soil would yield 5.24 inches to the ground water supply. Soil sampling over a longer period indicated there was a further drainage of 0.87 inches. The above computations indicate that about six inches of water pene- trated below the root zone as the result of the occurrence of 2.16 inches of natural rainfall on April 4—5, supplemented by the application of 8.49 inches of artificial rain on April 6 and 8, a total of 10.65 inches within less than five days. Rainfall data for the 1928-29 season are shown in Table 9. In Table 10 is given the average soil moisture content. The transpiration use of water by brush during summer is shown in Table 11. Plate V shows the variation in moisture content at various depths. PLATE V tr 8 1 1 1 1 1 11 1 1 '^ ■^ — -s TO 2-Ff:ET IN pEPTH | 4 ,^ ^ N s ■^ , -o. ^^ u - " ~~~ y —. u ■<^ . i, y ^v -^ 2 TO 6-FEEt IN DEPTH | Z' — »>-. 12 \ \ 13- FOOT DEPTH _ NORTH TUNNEL 8 /I \ >-s / L. 4 / t>~ ►— <« / -4 12 ~ ' h 1 "— ■ T 20-FOOT DEPTH J i- , ^ 8 ' ' '— ^ ' ■■^ / >^ 4 / -~ ' — — — > n 1 1 1 I 1 1 I I RAINFALL BY STORMS jtor m total 1 J .1 1 L _L Jan. Feb. March April May June July Au^. Sept. Oct. Nov. Dea VARIATION IN MOISTURE CONTENT AT DEVIL CANYON PLOT. 1929. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER TABLE 9 RAINFALL RECORD, 1928-29, DEVIL CANNON SHAFT, SAN BERNARDINO 39 Date Rainfall in inches 8-inch gage 3-inch gage 1928— October 11-12 0.79 1.17 1.11 .76 1.16 055 1.91 2.35 .36 .59 2.23 .07 .71 2.16 .41 November 13-14 1.06 December 3-4 .72 December 13-15 1.08 1929- 0.51 January 19-21 1.80 2.26 February 5-6 .34 .55 March 9-10 March 13 2.18 .06 March 23-24 April 4-5 April 20 .68 2.09 .40 Total natural rainfall 16.33 Artificial rainfall — Aprils 3.26 5.23 Aprils Total ■- 24.82 TABLE 10 AVERAGE MOISTURE CONTENT AT DEVIL CANYON SHAFT, SAN BERNARDINO, 1929 January 10--. February 12.. March 9 March 21 April 3 April 11 April 13 April 15 April 17 April 20 April 23 April 25 May 2 May 13 May 15 May 31 Jime 8 June 13 July 1 August 1 August 27 September 26. November 1.. Deceinber 11. Dates of sampling Average moisture content of soil 0-2 feet In per cent 5.0 7.6 5.6 6.7 7.1 4.0 2.7 2.4 1.9 1.4 '2.9 1.3 2-6 feet In per cent 2.9 7.5 6.4 7.3 5.1 4.1 3.7 3.1 1.8 North tunnel (13-foot level) In per cent 1.5 1.7 1.7 13.2 12.4 9.9 9.1 8.9 6.5 5.8 5.2 4.6 2.3 2.2 'i'7" West tunnel (20-foot level) In per cent 5 4. 4.2 40 DIVISION OF WATER RESOURCES TABLE H TRANSPIRATION USE OF WATER BY BRUSH AT DEVIL CANYON SHAFT PLOT, SAN BERNARDINO May 1 to August 1, 1929 Period Number of days Depth in feet Use of water For period Zone Per foot Rate per 30 days May 15-May31. May 15-May 31- May 15-May Si- May 15-May 31- May 31-July 1 — May 31-July 1— May 31-July 1 — May 31-July 1— July 1- August 1-. July 1-August 1.. July 1-August 1-. July 1-August 1-. May 15-August 1 May 15-August 1 May 15-August 1 May 15-August 1 May 1-August 1- May 1-August 1- May 1-August 1. May l-Augiist 1. 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 In inches 0.55 .74 .46 ^ '1.75 0.34 .74 2.94 >4.02 0.21 .96 4.19 5.36 1.10 2.44 7.59 11.13 1.58 3.09 7.99 12.66 In inches 0.28 .19 .05 0.17 .19 .29 0.11 .24 .42 In inches 1.03 1.39 .86 3.28 0.33 .72 2.84 3.89 0.20 .93 4.06 5.19 0.55 .61 .76 0.79 .77 .80 ' Corrected for drainage. Season 1929-30. — An inspection of the north tunnel on April 18, 1930, showed that the rainfall previous to that date (totaling 15.46 inches) had penetrated to a depth of thirteen feet. Thus 10.25 inches were stored in the soil, leaving 5.21 inches lost by evaporation and transpiration. The rainfall beginning April 30th and ending May 7th amounted to 4.58 inches. Assuming that four inches of the rain were effective and that 2.25 inches were required to meet the deficiency of soil moisture in the root zone between thirteen and sixteen feet, about 1.75 inches passed below the root zone. This is substantiated by the fact that the moisture content at the 20-foot level increased from 4.5 per cent to 6.9 per cent, 0.44 inch per foot or 1.76 inches for the four-foot section (sixteen to twenty feet) below the root zone. Table 12 gives the rainfall data for the 1929-30 season, Table 13 the average soil moisture content, and the transpiration use of water by brush during the summer is given in Table 14. Plate VI shows the variation in moisture content of soil at different depths. i RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 41 TABLE 12 RAINFALL RECORD. 1929-30, DEVIL CANYON SHAFT, SAN BERNARDINO Date Rainfall in inches Date Rainfall in inches 1929— September 17 . 0.70 0.75 4.05 1.89 .07 .52 2.22 .60 3.91 1930— March 31 75 1930— January 5- 8 April 20 34 April 21 . . 52 January 14-15 April 29-30 1 43 January 18 May 1-2 .80 January 27 May 3. 99 February 20-26 May 4 ... .86 March 5 .. ... May 6 16 March 14-19 May 7 34 Total 20 90 TABLE 13 AVERAGE MOISTURE CONTENT AT DEVIL CANYON SHAFT, SAN BERNARDINO, 1930 January 9. January 20 . January 22. May 13 May 15 May 20 May 28.... June 6 June 21 July 23 August 20-. Dates of sampling Average moisture content of soil 0-2 feet In per cent ---- '6.0 2.6 1.6 1.3 2-6 feet In per cent '6.0 4.3 2.4 1.9 North tunnel (13-foot level) In per cent 1.4 8.7 7.3 5.6 3.0 2.0 West tunnel (20-foot level) per cent 4.5 4.5 5.6 6.1 6.4 6.8 6.9 6.4 6.1 5.9 > Estimated. TABLE 14 TRANSPIRATION USE OF WATER BY BRUSH AT DEVIL CANYON SHAFT PLOT, SAN BERNARDINO May 15 to August 23, 1930 Period Number of days Depth in feet Use of water For period Zone Per foot Rate per 30 days May 15- June 21.. May 15- June 21... May 15-June 21... May 15-June 21__. June 21-July 23-_. June 21-July 23... June 21-July 23... June 21-July 23... July 23-August 20. July 23-August 20. July 23-August 20. July 23-August 20. May 15-August 23 May 15-.\ugust 23 May 15-August 23 May 15-August 23 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 0- 2 2- 6 6-16 0-16 In inches 1.44 1.25 3.12 5.81 0.46 1.40 2.70 4.56 In inches 0.72 .31 .31 0.23 .35 .27 0.37 1.82 2.19 1.90 3.02 7.64 12.56 0.09 .18 0.95 .76 .76 In inches 1.17 1.01 2.53 4.71 0.43 1.31 2.53 4.27 42 DIVISION OF WATER RESOURCES PLATE VI 6 1 M 1 1 M M TO 2-FEET IN DEPTH 4 ' ■^ k ^_ 8 ""t*" — — 1 : 1 1 2 TO 6- FEET IN DEPTH | 4 — 1 1 - - '--. t>^ 6 1 \ 13- FOOT DEPTH J / S NORTH TUNNEL 4 / ~-i ^ 1 / ■o~. __ -^ 8 ^ -»■ ^ 20- FOOT DEPTH | 4 „ , , _, ^ WEST r TUNNCl. 1 _j 1 1 1 1 1 1 1 RAINFALL BY STORMS /Storm 1 Ota! 1 f ' / / / f L\ . 1 1 ^ 1 L Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. VARIATION IN MOISTURE CONTENT AT DEVIL CANYON PLOT, 1930. Muscoy Plots. The Muscoy brush plots, I and J, are located near Cajon boulevard about five miles northwest of San Bernardino. The growth is medium brush, chiefly chamisal and wild olive, with almost no grass. Plate VII shows the type of brush cover. The soil to a depth of eighteen feet is a coarse Hanford gravelly sand having an apparent specific gravity of 1.60. Table 15 gives the field capacity, initial fall moisture content and initial deficiency below field capacity for various depths in the two plots. The disposal of rain and winter evaporation and tran- spiration rates are presented in Tables 16, 17, 18 and 19. These results are based on soil samples taken during 192S, 1929 and 1930. Four points of sampling are located on each plot. During this period there was no percolation below the root zone at Plot I. At Plot J there was none during the 1927-28 season, and only 0.6 inch or less during that of 1928-29. Claremont Tunnel Plot I. The Claremont brush plot with tunnel is located four miles north- west of Ontario. The tunnel was driven in 20 feet from the side of a gravel pit with the roof of the tunnel 22 feet below the ground surface. Work is carried on here in a manner similar to that employed at Devil Canyon, except that it is on a less extensive scale. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 43 PLATE VII MUSCOY BRUSH PLOT J. AUGUST, 1930. TABLE 15 FIELD CAPACITY, INITIAL FALL MOISTURE AND INITIAL DEFICIENCY AT VARIOUS DEPTHS IN MUSCOY BRUSH PLOTS I AND J Initial Depth Field Initial fall moisture content in per cent deficiency below field Plot in capacity capacity feet in per cent (total to depth) in inches Plot I 0- 3 4.67 0.8 2.23 3- 6 4.00 1.6 3.61 6- 9 4.00 1.7 4.94 9-12 4.00 1.7 6.26 12-15 4.00 1,6 7.64 15-18 4.00 1.6 9.03 PlotJ 0- 3 3- 6 5.50 4.00 0.9 1.2 2.65 4.26 6- 9 4.00 1.5 5.70 9-12 4.00 2.1 6.80 12-15 4. CO 2.6 7.60 15-18 4.00 3.2 8.07 44 DIVISION OF WATER RESOURCES TABLE 16 DISPOSAL OF RAINFALL AT MUSCOY BRUSH PLOT I, 1927 TO 1930 o > o > H H H o' y 1 g'g-i 5T^- » 5-< 2.0 3 5" ^•s-° 5'o — 3§ o o. i" 1 5-S"£ ? S- 2,2, <« 3 |3- ||. g'o. 3 w unt of rain and sto 1 moisture lost aporization-transp n since last date npling in inches... p_ a' s- p 5' 5" 2 p -'3 5g 5'3. 3-£, 3 I ? 2, p 3 n re o Too "■ s grs- S3 rf «3 o s: g§ 12, n ^ D"P 8 5- 5-1 5'S ; £.?^a 2 O' ?§. =1:3 1 ^ Season 1927-28— Initial moisture defi- 9.03 February 8 . 12.84 5.79 7.05 3.24 0.00 April 26 3.70 —4.23 7.93 16.54 1.56 14.98 7.47 0.00 Season 1928-29— October 10 ... 0.00 4.99 10.16 0.00 .. 9.03 6.71 3.39 4.99 5.17 +2.32 +3.32 2.67 1.85 2.32 5.64 2.67 4.52 00 February 8 0.00 May 15 6.17 —3.22 9.39 16.33 2.42 13.91 6.61 0.00 Season 1929-30— Initial moisture defi- 9.03 0.70 0.29 0.41 8.74 0.00 7.28 +5.79 1.49 7.98 6.08 1.90 2.95 0.00 TABLE 17 DISPOSAL OF RAINFALL AT MUSCOY BRUSH PLOT J, 1927 TO 1930 o > O > H H H cc 'tJ s- 2 p o rr^- a are g B S o < 2.0 °'p ?5-^ g'd5-5 2, s. unt of 1 moi aporiz n sine upling 3* i.P -3 5'2 =•11 ^•o S-'^ 3 n re B-3-^ S re» ^ -,g S'" S-.s- 3 ° 5-3. §-g.3 §0 B "S. 5' OQ l! > M W > °0 — m P vera trai seas dav 5-^ g-i> 5'2 3 -a ™ £^ o ^ 2p2, •a j^. S§g -.3S. Period p p B. S-? ^&i „.o o 3 = IT 5' 5' 0.3 O m 3 a 5"2. PI- •g™ 3 _. " a. crP o- o —. m o" ; §•§ w5"2 ' ' P-3 ' a o'<: 7 Season 1927-28— October 25-Februarv 8 106 78 12.84 3.70 5.79 1.56 7 05 7.93 2.00 .. February 8-April 26 3.05 _.. October 25-Apnl 26 184 16.54 1.56 14.98 2.44 Season 1928-29— October 12-December 27 76 43 4.99 5.17 2.32 5.64 2.67 1.85 1.05 -. December 27-February 8 - 1.29 -_. February 8-May 15-.. . 96 6.17 2.42 9.39 2.93 -._ October 12-May 15 215 16.33 2.42 13.91 1.94 Season 1929-30— 25 7.28 6,08 1.20 1.44 _., TABLE 19 WINTER EVAPORATION-TRANSPIRATION RATES AT MUSCOY BRUSH PLOT J, 1927-1929 •z > > H » > c B 3'3- S'S, Hi 3-2.- S p2. 5 2 TO 3 ■g -• S 3 CI. veragerat transpira season ii Period a^ ^ ri- 2 p i'? ^&l „.o o 3 3 !r^ 5* 3 S.3 3-§ D.TO 5^ 2"3 p TO •S3 11 |t3 ? 1 ^ S" 'S'i^p -• P ST. p- o *-- : 5-g coS'g ■ ' 1 ^ 1 C7 o"< Y Season 1927-28— October 25-February8-_-_ February 8-April 26 October 25-April 26 106 13.21 5 92 7 29 2 06 78 4.13 3 12 6 93 2 67 184 17.34 3.12 14.22 2.32 Season 1928-29— October 12-December 27 76 43 5.34 6.04 3.62 8.67 1.72 99 0.68 ... December 27 — February 8- February 8-May 15 October 12-May 15 0.69 .. 96 6.81 4.84 10.64 3.32 .. 215 18.19 4.84 13.35 1.86 Over the tunnel there is a medium thin growth of brush (wild olive and sage) growing from two to three feet high, with a fair grass sod. Plate VIII shows the brush cover and soil profile. The soil types are sandy loam and rock, 0-2 feet, and sand-rock and gravel, 2-22 feet. During the three seasons 1927-28, 1928-29 and 1929-30 all of the rain was held within the root zone and transpired or evaporated. The consumptive use therefore was equal to the rainfall each season, as follows : Season 1927-28 1928-29 1929-30 Rain 14.93 inches 12.66 inches 16.35 inches Consumptive use 14.93 inches 12.66 inches 16.35 inches 4o DIVISION OF WATER RESOURCES PLATE VIII 4 1 1 H J. ,v- ' '•■ . f* ■ - S ^^^ *S-#:>iii^'it<-_«^^'- CLAREMONT TUNNEL PLOT. AUGUST, 1930. A. Cover Crop. B. Soil Profile. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 47 It is evident from the data for the season of 1929-30, given in Table 20, that at this location not less than 20 inches of rain would be required before deep penetration below the root zone would occur. The average rate of evaporation-transpiration from January 5 to June 3, 1930, was at the rate of 2.8 inches per 30 days. Table 20 gives tj^ical results of soil sampling. In May, 1930, a steam shovel was working through a section 500 feet north of the plot. The entire face of the cut, which was 40 feet deep, was moist and the samples taken May 14, 1930, from a depth of 32.5 feet are representative of field capacitj'. The total rain to this date was 16.12 inches and apparently deep penetration had occurred in this area. The overlying cover of brush had been kept partially removed where the shovel was working. TABLE 20 AVERAGE MOISTURE CONTENT AT CLAREMONT TUNNEL BRUSH PLOT I, 1929 AND 1930 Average moistiire content of soil Depth of sample in feet October 9, 1929 February 1, 1930 May 31, 1930 June 3, 1930 SP LP SP LP SPs LPs P Ps P Ps 1 3.4 1.2 1.1 10.4 3.4 3.4 2.8 2.4 5.4 12.6 4.7 5.9 12.0 8.5 2.1 6.3 1.9 1.9 1.8 3.8 4.7 2.9 7 2 4 1 3 0.7 4 8 4 3 5 5 1 6 7 1 7 3 8 7.8 4.3 Penetra 2.9 2.8 tion 8 3 1.8 7.7 feet 4.2 9.9 8 2.6 3 9 8.7 7.0 9 2.4 1.7 1.8 1.7 1.8 1.7 4.3 1.5 1.4 1.9 1.7 1.8 1.8 4 10 3 2 10.5 3 1 11 3 11.5 3 1 12 2 8 12.5 4 3 13 2 1 14 2 3 15 3 1 15.5 . ._ 2 8 16 3 3 17 3 8 18 19 - - - 2.4 1.8 1.2 3.4 3.5 3.2 20 21 Note: S=small sample of from 200 to 400 t;rams. L=large sample of from 2000 to 4000 grams. P=per cent of moisture content based on oven-dry weight of entire sample. Ps=per cent of mobture content based on oven-dry weight of soil in sample. Remarks: .\t 22 feet in roof of tunnel, January 20, ^928, the per cent of moisture in soil was SP 2.3 and LP 2.7. At 32.5 feet below the surface in an area 500 feet north of tunnel, the average moisture content on May 14, 1930, was SP 3.7 per cent and SPs 6.1 per cent. Palmer Canyon Plot K. The Palmer Canyon brush plot is located eight miles north of Ontario at an elevation of 1800 feet. The soil is classified in the Placentia series and is a compact red clay loam to a depth of four feet, grading into a coarser sandy loam at seven feet. The cover is a dense mass of weeds, grass, and brush not over two feet high at the points of sampling. Plate IX shows the brush cover and soil profile. 48 DIVISION OF WATER RESOURCES PLATE IX ■1^ '•If..-' • PALMER CANYON BRUSH PLOT. AUGUST, 1930. A. Cover Crop. B. Soil Profile. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 49 The total rainfall for the period from January 5 to June 9, 1930, was 19.08 inches. The amount stored in the soil on June 9 was 3.23 inches. Since there was no run-off from the plot, the evaporation and transpira- tion losses for that period amounted to 15.85 inches, occurring at an average rate of 3.07 acre-inches per acre per 30 days. In a season when the rains are widely distributed from October 1 to May 1, this plot would have a capacity for 30 acre-inches per acre per year consumptive use without any deep penetration below the root zone. Table 21 shows field capacity, initial fall moisture content and initial deficiency at various depths. Table 22 gives a summary of moisture percentages for 1929-30. TABLE 21 FIELD CAPACITY, INITIAL FALL MOISTURE CONTENT AND INITIAL DEFICIENCY AT VARIOUS DEPTHS IN PALMER CANYON BRUSH PLOT K Depths of zone in feet Field capacity in per cent Initial fall moisture content in per cent Total initial deficiency below field capacity for entire depth to bottom of zone in inches 0-1 18.0 19.0 18.0 15.5 14.5 11.0 3.7 7.0 10.1 8.6 7.6 6.6 2.75 1-2 5.05 2-3 6.57 3-4 4-5 7.89 9.22 5-6 10.06 TABLE 22 AVERAGE MOISTURE CONTENT AT PALMER CANYON BRUSH PLOT K .\verage moisture content of soil Depths of zone in feet Date of sampling October 1, 1929 January 24, 1930 February 4, 1930 March 28, 1930 June 9, 1930 0-0.5 In per cent In per cent In per cent 20.2 16.1 19.0 17.8 14.8 7.6 6.6 In per cent 11.1 12.4 17.9 18.2 15.5 14.4 10.8 9.3 6.6 8.5 9.6 In per cent 4.4 0.5-1 . 3.7 7.0 10.1 8.6 5.7 1 - 2 9.7 2 -3 3 - 4 12.4 12.6 4-5 11 6 5-6. 9.1 6 - 7 9.2 7-8 7 6 8-9 - - 8.2 9 -10 7.2 4.1 4.3 6.1 Special Plots. A very favorable opportunity for the study of the disposal of rain in the rocky brush covered areas was presented in Januarj-, 1930. A rain extending from January 5 to January 15 fell on dry soil and penetrated to depths below six feet. It was possible then, with the known rainfall and the observed depths of penetration, to compute the initial fall deficiency in moisture content below field capacity. 4— S1141 50 DIVISION OF WATER RESOURCES I Plots had been established at seven points on the rocky brush covered fans extendinfj: from San Antonio Creek eastward to Day Creek. In October, 1929, oach plot was sampled to a depth of three feet. The plots were sampled again in February, 1930, from eighteen to twenty-eight days after the rainfall of January 5 to 15. The samples in February were obtained from dug pits two feet wide by five feet long, excavated to depths below the line of rainfall penetration. Rainfall records for the storm period are given in Table 23. There was no surface run-off at any of these locations during this storm. The evaporation from a free water surface from a Class A Weather Bureau type of pan located at Ontario is given below. The values are for the 24-hour period ending at 7 :00 a.m. on the date given. Date, 1930 Evaporation in inches Date, 1930 Evaporation in inches 03 .01 .03 .04 .02 .02 January 12 .. 0.03 January 7 .02 January 14 .01 January 9 .02 .00 Total, January 6-16 0.23 TABLE 23 COMPARISON OF RAINFALL AT NINE FOOTHILL STATIONS FOR STORM OF JANUARY 5 TO 15, 1930 Observer Location Elevation above sea level in feet Storm total in inches 1,700 1,750 2,050 2,250 1,700 1,650 1,850 1,350 1,450 7.04 7.28 East Twenty-fifth street, San Antonio Heights North end of Cornelia n avenue 7.19 6.99 6.95 Reed 7.56 Cherbak 7.36 Smith 7.15 7.61 7.24 The free water loss from a Class A Weather Bureau type of pan is shown to be 0.23 inch for the ten-day storm period. The evaporation loss from the rain storm was therefore set at 0.20 inch and the remainder considered as effective in replenishing the storage in the soil. There was no surface run-off during this storm at any of these plots. The depths of major root activity are considered to be ten feet for the more compact red sandy loams and sixteen feet for the looser sands and sandy loams. The results from the seven plots are summarized in Table 24. Plot B2. — The soil classification is Ilaiiford stony sandy loam. The rocks are two inches or less in diameter down to a depth of three feet. Below three feet there are many rocks from three to ten inches in diameter, with a few from fifteen to twenty inches in diameter. The RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 51 brush cover, consisting: mainly of cliamisal, is moderately dense, ranging in height from one to three feet. TABLE 24 PENETRATION OF RAIN AND FALL DEFICIENCY IN SOIL MOISTURE CONTENT AT SEVEN LOCATIONS ON THE ROCKY BRUSH COVERED FANS OF SAN ANTONIO, CUCAMONGA, DEER AND DAY CREEKS Plot number Total rain in storm of January 5 to 15, 1930, in inches Penetration in feet Fall deficiency in moisture content per foot in inches Depth considered in feet Total deficiency in moisture content in inches B2 B3 B4 B5 7.28 7.19 7.:6 7.28 7.61 6.99 7.36 10.2 7.0 9.6 Below 8.0 8.5 6.0 10.3 0.69 1.00 .75 .50 .87 1.13 .70 16 10 16 16 16 10 16 11.1 10.0 11.9 8 B 6 14.0 B7 B8 11.3 11.1 11,1 For the top - 10.2 feet of soil, the average storage of rain equals 7.08-:-10.2=0.69 inch per foot of soil. The fall moisture content there- fore has an equivalent deficiency of 11.1 inches in sixteen feet of soil. Plot B3. — The soil classification is Ilanford gravelly sandy loam. It is a semicompact soil and there are not many large rocks. The brush cover is moderately dense, averaging about three feet high. There was a good growth of green grass, two or three inches high, under the brush on February 4, 1930. For the top seven feet of soil, the average storage of rain equals 6.99^-7.0=1 inch per foot of soil. The fall moisture content therefore has an equivalent deficiency of ten inches in ten feet of soil. Plot B4. — The soil classification is Tu.iunga stony sand. There are very few rocks to a depth of 3.5 feet. From 3.5 to 7.7 feet the rock content is high, but from 7.7 to 10.0 feet the profile shows mostly sand. In October, 1929, there was a medium growth of brush ranging from 2.5 to 10.0 feet high, but this was burned off so that in February, 1930, the surface was clean. For the top 9.6 feet of soil, the average storage of rain equals 7.16 — 9.61=^0.75 incli per foot of soil. The fall moisture content there- fore has an equivalent deficiency equal to 11.9 inches in sixteen feet of soil. Plot B5. — The soil classification is Tu.iunga stony sand. The top foot is of relatively fine material, but from two to eight feet the profile shows coarse gravelly sand with many rocks and boulders up to 24 inches in diameter. There is a fairly dense growth of scrub oak, ten feet high, at this location. For the top eight feet of soil, the average storage of rain equals 0.5 inch per foot of soil. The fall moisture content therefore has an equivalent deficiency equal to eight inches in the top sixteen feet of soil. Plot B6. — The soil classification is Ilanford stony sandy loam. The top two feet are gravelly; the third foot has many rocks from two to 52 DIVISION OP WATER RESOURCES ('ip:lit inches in diameter; and from four to nine feet the profile shows coarse sand and rock. There is a fair growth of brush, mostly wild olive about two feet high. For the top 8.5 feet of soil, the average storage of rain equals 7.41-f-8.5^=0.87 inch per foot of soil. The fall moisture content there- fore lias an equivalent deficiency equal to fourteen inches for sixteen feet of soil. Plot B7. — The soil classification is Ilanford gravelly sandy loam. It is a coarse sandy loam with relatively few rocks to a depth of 6.5 feet. The brush cover is quite dense and is from two to three feet high. For the top six feet of soil, the average storage of rain equals 6.79-^6.0^1.13 inches per foot of soil. The fall moisture content there- fore has an equivalent deficiency equal to 11.3 inches in ten feet of soil. Plot P>8. — The soil classification is Ilanford stony sandy loam. Over 50 per cent of the material, by volume, is rock ranging from six inches to two feet in diameter. One rock 3.5 feet in diameter was removed in excavating the hole. The brush cover is dense and is mainly chamisal from three to four feet high. For the top 10.3 feet of soil, the average storage of rain equals 7,16-^10.3=0.70 inch per foot of soil. The fall moisture content there- fore has an equivalent deficiency equal to 11.1 inches for sixteen feet of soil. General Stations. No. 75. — The soil is classified as Hanford gravelly sand. The plot is located seven miles northwest of San Bernardino. The brush cover is four feet high and quite dense, and consists mainly of chamisal, wild olive and sage brush. TABLE 25 RESULTS OF SOIL SAMPLING AT GENERAL STATION No. 75-BRUSH 1928 and 1929 Average moisture content of soil Depth of .sample in feet Season of 1927-28 Season of 1928-29 January 26, 1928 April 27, 1928 June 30, 1928 September 25, 1928 December 27, 1928 Mav- is, 1929 June 30, 1929 0- 1 In per cent 8.7 3.3 2.5 2.6 1.8 1.8 1.1 1.2 2.1 1.0 2.0 1.9 In per cent 1.7 3.0 1.4 In per cent In per cent 1.1 1.7 0.6 In per cent 8.6 6.6 3.5 1.0 9 0.7 In per cent 2.7 2.7 1.9 In per cent 1- 2 2- 3 3- 4 4- 5 2.9 2.2 3.1 2.9 2.1 1,5 1.1 0.8 1.0 6-6 6- 7 7-8 8- 9 9-10 -- . 10-11 11-12 12-13 Depth of penetration in feet 3.8 2 3 8 Seasonal rain to date in 9.33 16 54 17.67 4 99 16 33 16.50 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 53 There was no penetration of rain below the root zone during the seasons of 1927-28 and 1928-29. The maximum depth of penetration was eight feet, noted in May, 1929. There was no run-oif. During the two seasons of 1927-28 and 1928-29, all of the rain was held within the root zone and transpired or evaporated. The consump- tive use of water was therefore equal to the seasonal rainfall, which amounted to 17.67 inches in 1927-28 and 16.50 inches in 1928-29. Table 25 gives the results of soil moisture determinations. Xo. 76. — This station is located five miles northwest of 8an Bernardino. The soil is classified in the Hanford series. It is a coarse, sandy, gravelly loam to a depth of three feet and then gravelly sand to fifteen feet. The cover consists of a scattered growth of chamisal and wild olive from twelve to eighteen inches high, and a fair sod of grass. There was no penetration of rain below the third foot in either of the seasons of 1927-28 or 1928-29. Due to the seasonal distribution of the storms, the rains were transpired or evaporated shortly' after they fell and there was no cumulative storage of rain. The season of 1929-30 was more favorable for deep penetration and the rains had penetrated to a depth of 12.5 feet by April 18, 1930. Soil moisture records are given in Table 26. No run-off occurred from the plot during the last three years. Winter rates of evaporation and trans- piration were as follows: Date Period Amount of rain stored in soil at end of period in inches Total rain to date in inches Average rate of evaporation- transpiration for winter season per 3D days in inches April 27, 1928 May 15, 1929 October 25, 1927, to April 27, 1928... _ October 12, 1928, to May 15, 1929 0.35 0.64 16.54 16 33 2.63 2.19 TABLE 26 RESULTS OF SOIL SAMPLING AT GENERAL STATION No. 76-BRUSH 1928, 1929 and 1930 Average moisture content of soil Depth of sample in feet Season of 1927-28 Season of 1928-29 Season of 1929-30 January 26, 1928 April 27, 1928 June 30, 1928 December 27, 1928 May 15, 1929 June 30, 1929 September 26, 1929 April 18, 1930 June 30, 1930 0- 1 In percent 8.6 6 2 5 5 2.1 1.6 1.9 1.6 14 1.4 1.5 14 1.5 1.4 1.5 1.8 In per cent 2.5 2.6 2.6 2.0 In percent In per cent 7.2 3.6 2.5 2.0 2.2 1.4 In per cent 3.0 3.5 2.7 1.8 1.5 1.3 1.0 1.1 1.1 0.9 1.0 0.9 In per cent In per cent 3.8 2.1 2.3 In per cent Dry Moist Moist Moist Mobt Mobt Moist Moist Mobt Moist Mobt Mobt Dry Dry Dry In per cent 1- 2. 2- 3 3- 4 4- 5 5- 6 6- 7 7- 8 .. 8- 9 9-10. 10-11 11-12 . 12-13 .... 13-14 14-15 Depth of penetration in feet 2.8 1.5 12.5 Seasonal rain to date in inches. 9.33 16.54 17.67 4.99 16.33 16.50 0.70 15.46 20.90 54 DIVISION OP WATER RESOURCES No. 101. — The soil type is Ramona loam and the cover consists of a medium growth of brush about three feet high and a fair sod of grass. The penetration from 11.15 inches of rain to April 18, 1930, was six feet. Below six feet tlie soil was dry to ten feet and then partly moist to thirteen feet. There was no run-off from the plot. Summary of the Disposal of Rainfall on Brush Plots. The results of the last three years Avork indicate that at least nine- teen inches of seasonal rainfall is necessary before any material amount of water will penetrate below the root zone of the brush on the valley floor. A seasonal rainfall of less than nineteen inches is usually consumed by the brush cover before any portion of it reaches the ground water. Table 27 gives a summary of the disposal of rainfall on the brush plots. Table 28 gives a summary of average winter rates of evaporation-transpiration and initial fall deficiency in soil moisture content for brush-covered areas. TABLE 27 SUMMARY OF DISPOSAL OF RAINFALL ON BRUSH PLOTS, 1927 TO 1930 Location Season Rainfall in inches Evaporation and transpiration in inches Penetration below root zone in inches Devil Canyon Shaft Muscoy-PIot I 1927-28 1928-29 1929-30 1927-28 1928-29 1927-28 1928-29 1927-28 1928-29 1929-30 1929- 1927-28 1928-29 1927-28 1928-29 ■32.00 ■24 82 20.90 17.67 16.50 18.54 18.19 14 93 12.66 16.35 19.58 17.67 16.50 17.67 16.50 27.00 18.82 19.10 17.67 16.50 18.54 17.59 14.93 12.66 16.35 19.58 17.67 16.50 17.67 16.50 5 6.0 1.8 0.0 Muscoy Plot J-_ 0.6 0.0 Palmer Canyon 0.0 0.0 0.0 Station No. 75 Station No. 76 0.0 ■ Includes artificial rain. GRASS AND WEEDS Devil Canyon Plot B. The Devil Canyon plot B is located one-half mile southeast of the shaft brush Plot A. It offers an opportunity to compare the penetra- tion of rain on brush-covered areas with that on grass and weed land. The soil t.ype is a Hanford gravelly sandy loam. The land was cleared for grain about 1918, but has not been farmed since 1926. Pits were dug for the purpose of soil sampling at the beginning and end of the rainy season and after the major rain storms. The grass and weed cover on Plot B is relatively thin and the winter rate of evaporation-transpiration is low. The initial fall deficiency in soil moisture content is 6.9 inches, whereas for the shaft brush Plot A it was 12.5 inches. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 55 TABLE 28 SUMMARY OF AVERAGE WINTER RATES OF EVAPORATION-TRANSPIRATION AND INITIAL FALL DEFICIENCIES IN SOIL MOISTURE CONTENT FOR BRUSH COVERED AREAS Plot Season Average winter rate of evaporation- transpiration per 30 days in inches Initial fall deficiency in moisture content of the soil in inches 1929-30 1927-28 1928-29 1927-28 1928-29 1929-30 1927-28 1928-29 1928-29 1929-30 1929-30 1929-30 1929-30 1929-30 1929-30 1929-30 2.80 2.44 1.94 2.32 1.86 3.07 2.63 2.19 Muscoy I 9.0 Muscoy J 8.1 10.1 General Station 76 12.5 Brush, B2 _ _ . 11 1 Brush, B3 . . 10.0 Brush, B4 11.9 Brush, B5 8.0 Brush, B6 - 14.0 Brush, B7 11.3 Brush, B8 11.1 2 40 10.6 Deep penetration below the root zone may be expected on the grass and weed Plot B after from ten to twelve inches of seasonal rain has fallen. This may be compared with a requirement of eighteen to twenty-two inches for the shaft brush Plot A. However, it should be noted again that the winter grass and weed cover on Plot B is thin. Other plots where the soil supports a denser grass and weed cover have shown a consumptive use of from twelve to fifteen inches or more. The depth of root activity was found to be eight feet. The soil moisture deficiency November 3, 1928, was 6.91 inches. On February 21, 1929, the total rain to date was 10.75 inches, and the soil had been wet to field capacity to eight feet. Some moisture had penetrated below the root zone. The soil moisture deficiency September 26, 1929, was 6.97 inches. On January 22, 1930, the total rain to date was 7.46 inches, the storage of moisture in the root zone was 5.87 inches, the loss by evaporation was 1.59 inches, and the remaining soil moisture deficiency was 1.10 inches. The results of soil sampling are given in Tables 29 and 30. Pyle Shaft Plot II. The Pyle shaft plot II is located seven miles northeast of Ontario on the Deer Creek fan. The soil is classified as Tujunga stony sand. The condition of the grass and weed cover is shown in Plate X. The shaft was dug sixteen and one-half feet deep in January, 1928. A tun- nel was extended out ten feet from the shaft with the roof eleven feet below the ground surface. The material at the end of the tunnel was fairly uniform coarse sand with no large rocks such as were found in the top ten feet of soil. Kepresentative samples therefore were obtained readily by boring out laterally from the sides and ends of the tunnel at the thirteen-foot level. The tunnel was kept closed off from the shaft by a trap door. 50 DIVISION OP WATER RESOURCES a t^o><«<-* ja N CO 0) o ^•2 a S « "a eo t~t-OCM JS^ "5 Ifli t--' ■*' CO c 2 M OJ o V H a. a "a oa o» <»-<•* ja ^ ■«• 05000 3> c3 2 t^ .— o o Z"~ p. a 1 (N 00 i i ^eocooa ^ ■^ ^ I 1 e^co-»< U5 ■>!• e-icooco 00 00 o> N cffl-«l S t- o O 9^ a CO c "S e^oo CC -- 1^ >o o M-HOOOO c^ic^ 00 OJ t~ (n' « oJooio t^ ■*^ " CMCL, (1h Ph Q-i Cm P-i Oc ';;&<'!' £-2 o, WJ-J m JCCMnJ *"■ em c o. S M ! 1 toco 'o Q ill cfc a a 329- ruary 2 ruary 2 tember tember 930— uary 22 uary 22 uary 22 uary 22 ,-. c a a c ^AA^ \ o o •^ jaja o & ^ « >> >> S ''■^ S, o a o " > c o o s\ a a .■tJ CO S « u 2 rt " 3 3 g§°° S « S t» o e RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 57 TABLE 30 INITIAL DEFICIENCY IN SOIL MOISTURE CONTENT AT BEGINNING OF THE RAINY SEASON, 1928 AND 1929, DEVIL CANYON PLOT B Average deficiency of soil moisture Depth of sample in feet November 3, 1928 fSeptember 26, 1929 •^ i Per foot in inches iTotal in inches Per foot in inches ■Total "^ in inches 0-1 1.30 1.40 1.69 1.06 0.46 0.40 0.40 0.20 0.00 1.30 2.70 4.39 5.45 5.91 6.31 6.71 6.91 6.91 1.44 1.39 1.55 1.00 0.50 0.41 0.34 0.34 0.00 1.44 1-2 2.83 2-3 4.38 3-4 5.38 4-5 5.88 5-6 6.29 6-7 6.63 7-8 . . .. 6.97 8-9 6.97 ' Total deficiency of soil moisture from zero to base of section. When the shaft was dug, January 2, 1928, the depth of penetration was seven feet. The total seasonal rain on this date was 7.33 inches. Samples also were obtained from dug pits November 8, 1928, PLATE X PYLE SHAFT PLOT. AUGUST, 1930. February 26, 1929, and Febraary 11, 1930. These pits were located ten feet distant from a point directly over the end of the tunnel. On February 26, 1929, the depth of penetration was 5.4 feet. The total seasonal rain on this date was 9.48 inches. 58 DIVISION OF WATER RESOURCES The depth of major root activity appears to be nine feet as determined from du^" pits, the soil being dry to that depth in the fall. A few rootlets were found to extend to a depth of eleven feet. The amount and distribution of the rains during the 1927-28 and 1928-29 seasons were unfavorable for deep penetration. There was sufficient storage capacity within the root zone to hold the rains after they fell until they were either evaporated or transpired from the grass and weed cover. The seasonal rain for 1927-28 was 15.49 inches, and for 1928-29 the seasonal rain was 13.54 inches. The concentrated storms of the 1929-30 season caused penetration below the root zone. By February 6, 1930, the seasonal rain totaled 6.87 inches and this was sufficient to wet the soil to below the root zone, as evidenced by the tunnel samples at the thirteen-foot level. The amount of penetration could not be calculated as the soil was so rocky it could not be sampled regularly throughout the depth of the root zone. The 1929-30 seasonal rain amounted to 17.25 inches. Typi- cal results of soil sampling are given in Table 31. TABLE 31 RESULTS OF SOIL SAMPLING AT PYLE SHAFT PLOT II— GRASS AND WEEDS 1928, 1929 and 1930 Average moisture content of soil Depth of sample in feet November 8, 1928 February 26, 1929 October 10, 1929 February 11. 1930 SP LP SP LP . SP SP LP SPs LPs 1 2 In per cent 0.7 1.0 1.4 1.9 In per cent 1.4 0.9 0.8 1.3 In per cent 5.0 3.1 2.9 4.4 2.5 (Pcnetra 1.6 2.6 2.9 In per cent 3.0 In per cent 0.9 0.7 0.6 In per cent 5.4 3.0 6.9 In per cent 4.3 2.1 2.2 In per cent 6.1 4 7 7.3 In per cent 6.4 5.8 3 4 2.1 6.1 5 1.5 tion 5.4 ft.) g 1.2 1.5 1.2 1.1 7 2.3 8 6.2 6.5 3.8 4.2 9.4 8.3 11.5 g 2.5 2.2 1.9 1.9 11.2 10 January 9, 1928 April 11, 1928 April 17, 1929 February 6, 1930 May 7, 1930 May 13, 1930 13-foot level in SP 4.6 SP 4.0 SP 4.2 SP 6.0 SP 5.2 SP 6.2 Note: S=small sample of from 200 to 400 grams. L=large sample of from 2000 to 4000 granis. P=per cent of moisture ba.sed on oven-dry weight of entire sample. Ps=per cent of moisture based on oven-dry weight of soil in sam- ple. Special Rainfall Penetration Stations. During the 1927-28 rainy season, special rainfall penetration stations for intensive soil sampling were maintained in typical areas. A plot in crop and a clean cultivated plot are adjacent to one another at these stations. The clean cultivated plot is level and should give a maximum penetration, as the losses are by evaporation only. The adjacent plot in crop is on the undisturbed surface of the valley floor and the losses by evaporation, transpiration and run-off should give a minimum pene- tration. RAINFALL PENETRATION ATSTD CONSUMPTIVE USE OF WATER 59 The stations were equipped with run-off plots and standard rain gauges. The run-off plots were ten by ten feet, bordered with one by- twelve inch planks buried on edge in the ground to a depth of eight inches. Plate XI shows typical adjacent plots. Sets of soil samples were taken at four locations in each plot, in foot sections, to depths of from six to eighteen feet, and the moisture content of each sample was determined. The time interval between soil sampling was governed by the frequency and character of the rain storms. The total area of the soil disturbed on each date of sampling was five square inches, or 0.035 per cent of the plot area of 100 square feet. The soil sampling locations were never closer than one foot from any previous sampling hole, nor were samples ever taken closer than one foot from the border of the plot. Each hole was carefully backfilled with soil tamped in place. PLATE XI TYPICAL CLEAN CULTIVATED PLOT AND ADJACENT GRASS AND WEED PLOT. Station A. — This station was located two miles northeast of Anaheim on the property of the Anaheim Union Water Company. The soil is a Hanford fine sandy loam and is typical of a large area in Orange County. No run-off occurred at this station. Plot Al was clean cultivated early in December, 1927. The depth of major root activity was six feet and below that the soil was moist. The top six feet of soil is fine sandy loam, with an average field capacity of 9.25 per cent. From six to twelve feet the soil is a coarse sand with a field capacity of three per cent. The initial soil moisture deficiency below field capacity of the entire twelve-foot section was 5.8 inches. Early in February, 1928, the soil was filled to field capacity. A rain storm of 2.19 inches occurred early in March, and about 1.5 inches of rain water penetrated below the root zone. The total rainfall to April 15 was 12.39 inches, of which 4.9 inches were stored in the soil, about 1.5 inches penetrated to the ground water, and six inches were lost mainly by evaporation, although some transpiration occurred prior to the time the plot was clean cultivated in December. 00 DIVISION OF WATER RESOURCES Plot A2 was covered with grass during the winter months. A crop of weeds replaced the grass in May. The characteristics of soil in Plot A2 were the same as Plot Al, with the exception that the initial soil moisture deficiency was 4.6 inches instead of 5.8. The total seasonal rainfall of 12.58 inches was entirely lost by evaporation and transpira- tion. Plate XII shows the results obtained on Plots Al and A2 graphically. PLATE XII PLOT A -CLEAN CULTIVATED Rainfall stored in the Hnitial deficienc^y in the rool zone. This must be replenished before deep penetration occurs. PLOT A, -GRASS % , __ T 97^ -- y:-i ^ V ^ /Rainfall stored in the soil ( r ^ t , ■7-TTKrt-w.i 1 1, ►4.40 7.68 9.21 9.54 11.73 — Total rainfall to date in inches- RAINFALL BY STORMS 12.58 Depth of majoi activity-Jras; 7 f 5tor m t( tal f - - \l ll. 1 1 1 , ll ( E s u: "^ it -1- ,. 3.0 3.0 I 3.0 "^ 3.0 Oct. Nov 1927 Dec. Feb. 1928 March April May STORAGE OF RAINFALL IN THE SOIL, PLOTS A-1 AND A-2, ANAHEIM UNION WATER COMPANY. Station D. — Station D is located five miles south of Ontario. The soil in the top four feet is a Ilanford sand, grading into a silt loam at eight feet and becoming sandy again in the twelfth foot. During the winter of 1926-27 and summer of 1927, an extremely heavy crop of grass, weeds and sunflowers grew on the ])lots. The sunflowers were over six feet in height and results parallel heavy brush conditions rather than grass and M'ceds. The depth of root activity was eleven feet. The deficiency of soil moisture in the top twelve-foot section of each of the plots. Dl and 1)2, was 13.2 inches. On December 6, 1927, when the plots Avere started, two inches of moisture were stored in the soil out of a total rainfall of 3.78 inches. Thus 1.73 inches were lost by transpiration and evaporation from October 25 to December 6, 1927. No run-off occurred at this station. Plot Dl was clean cultivated and at the end of the rainy season 6.8 inches of rain had been stored in the soil. From December 6, 1927, to April 17, 1928, 2.99 inches were lost by evaporation out of a total of 7.79 inches of rainfall during that period. From December 6, 1927, to April 17, 1928, Plot D2, which was covered with a thin grass crop, showed a consumptive use of 6.19 inches. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 61 The total rainfall for the 1927-28 season was 12.74 inches. This was all lost by evaporation and transpiration. The results of Plot Dl and D2 for the 1927-28 season are sliown in Plate XIII. No rain penetrated below the root zone in either plot. Station E. — This station is located two miles southeast of Ontario. The soil is classified as a Hanford sand. The depth of major root activity was eleven feet. No run-off occurred at the station. Plot El was clean cultivated and started December 17, 1927. The initial soil moisture deficiency was 7.6 inches. The estimated con- sumptive use of water from October 27, 1927, to December 17, 1927, was 2.66 inches. From December 17, 1927, to April 17, 1928, 4.1 inches were lost by evaporation. The amount of rain stored in the soil at the end of the rainy season on April 17, 1927, was six inches. There was no penetration below the root zone. Plot E2 had an initial soil moisture deficiency of six inches. Grass was growing on the plot. Prior to December 17, 1927, the consumptive PLATE XIII PLOT D.- CLEAN CULTIVATED Rainfall stored in the soil ^^^ Nnitial deficiency in the root zone. This must be /repienisbed before deep penetration occurs. PLOT Dj -GRASS -\ / Rainfall stor d in the soil ~r^ •n M-tJ -rk^ y. -y ^ ^ >^ j\ / 1 i >4 ..Lli,,!,,, .. .x.\.. i. at £ 6 "3.73 5.71 718 9.18 10.61 — Total rainfall to date in inches- RAINFALL BY STORMS f Sand Depth of major r»t activity-grass and weeds. 7.4 ^ 14.4 * 14.7 -3 m 23.0 Q- 20.5 ? 12.5'^ 7.0 1 1 "-Storu total 1 ; ., 1 1 .III 1 1 , , Oct. Nov. 1927 Dec. Jan. Feb. March April May 1928 STORAGE OF RAINFALL IN THE SOIL, PLOTS D-1 AND D-2, EDISON AVENUE. use of water was estimated to be 1.26 inches. The consumptive use of water from December 17, 1927, to April 17, 1928, was 8.33 inches. There was no penetration of rain water below the root zone. The con- sumptive use of water for 1927-28 was equal to the total seasonal rainfall, or 14.06 inches. Plate XIV graphically shows the results obtained on Plots El and E2. 62 DIVISION OF WATER RESOURCES Station F. — This station was located on a Hanford loam soil at Cuca- monga. There was no run-off during 1927-28. The usual clean culti- vated plot was not estal^lished at this station. PLATE XIV PLOT E.- CLEAN CULTIVATED -*5.66 7.79 10.08 11.02 12.29 12.79 14.06 -Total rainfall to date in inches ' Depth of major root RAINFALL BY STORMS act,vitj,-grass and w«d^ ■ 1 1 1 ""■storm total ,f J 1 I ll i 1 7.5 7.5 ^ >% Oct. Nov. 1927 Dec. Jan. Feb. March April May 1928 STORAGE OF RAINFALL IN THE SOIL, PLOTS E-1 AND E-2, BRAUNDALE ACRES. The grass and weed plot had an initial soil moisture deficiency of 7.1 inches and the depth of major root activity was nine feet. No rainfall penetrated below the root zone. The consumptive use of water from October 26, 1927, to January 19, 1928, was 5.47 inches, and from January 19, 1928, to April 11, 1928, was 6.67 inches. The consump- PLATE XV PLOT F - NATIVE GRASS AND WEEDS r~ " 1_ VinitUI deficiency in th« root lone.This must b r«pl«tiish«d befcrt deep penetration occurs t^. X V ^Rainfall stortd in ttw toil 1 1 1 1 1 1 1 1 M -r-.__ / ^ 10 Depthof major root activity ^7^^ 4,0 1.33 _ 11.6 g SS i; 1.05 • III c 124 ^ 6.0 1. 125 a- 61 ^ .99 .c 11.7 t 6.5 „", .85 ?> — ILO^ 65 ? c .82 .S as 2 6.8 o si's 9.0 " 7.8.1 .22-5 a7 s 75 -c •2'S 7.5 L. /.5 .00 Tot al 7.09 STORAGE OF RAINFALL IN THE SOIL, PLOT F, CUCAMONGA. RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 63 tive use of water for 1927-28 was 13.89 inches and included all the rainfall. Plate XV gTapliically shows the results obtained on Plot F. Station G. — The location of this station was two miles east of Wineville at Glen Avon Heights. The soil is of a Placentia loam type and very compact. The trees growing on tlie plots depleted the moisture in the soil to a depth of seven feet, but they were pulled out several months before the rainy season started in 1927. No run-off occurred during ] 927-28. Plot Gl was clean cultivated and had an initial moisture deficiency of 8.2 inches. The consumptive use of water from October 26, 1927, to December 23, 1927, was about 2.8 inches. The evaporation from soil, December 23, 1927, to April 13, 1928, was about 5.3 inches. On April 13, 1928, 4.1 inches of moisture were stored in the soil. PLATE XVI PLOT G,- CLEAN CULTIVATED Mnitial deficiency in the root zone. This must be repi ■nish «p pirn trat PLOT Gj -VETCH » T J r _J^ r-r >> >>, /Rainf alls ore Jin the soil ol- _ _ _ _ _| _ .1 J J;i 1,, \ \^' 11 _ ►6.69 10.09 1 1 yStorm total { 1 i i 1 10.95 1Z.I8 13.35 -Total rainfall to date in inches ' Deptti of major root -}- lO RAINFALL BY STORMS activity - peaches * "g -*- 12 • Peach trees vwre pulled out in I9Z7 ri2.8™ 12.8 ^ ,2.5 § 12.4 L. 10.9 ^ 103 ■" 12.0 5 11.5 Q- 11.9 " ii.ol 9.8 ^ 8.Z Oct. Nov. 1927 Dec. Jan. Feb. March April May 1928 STORAGE OF RAINFALL IN THE SOIL, PLOTS G-1 AND G-2, GLEN AVON HEIGHTS. Vlot G2 had an initial soil moisture deficiency of 8.5 inches. A crop of vetch was growing on it during the winter. The consumptive use of water from October 26, 1927, to December 23, 1927, was 2.4 inches and from December 23, 1927, to April 13, 1928, was 8.1 inches. The consumptive use for 1927-28 season equalled the rainfall, 13.35 inches, Plate XVI graphically shows the results obtained on Plots Gl and G2. Station H. — This station was established two miles south of Redlands for the purpose of comparing rainfall penetration on an irrigated orange grove and on a nonirrigated barley field. The soil was a Placentia loam with gravel and sand below six feet. The plots were within 125 feet of each other and the major depth of root activity was five feet in each case. 64 DIVISION OF WATER RESOURCES Plot Hi was in an orange grove with a heavy cover-crop. The initial ^o\\ moisture deficioney was 3.4 inches. Some rain penetrated below the root zone before January 5, 1928, but after that the moisture in the root zone was used rapidly by the cover crop and no further pene- tration occurred. In Plot H2 a barley crop was growing and the initial soil moisture deficiency in the root zone was 4.3 inches. From October 25, 1927, to December 24, 1927, the consumptive use of water was 3.7 inches. During the period December 24, 1927, to April 2, 1928, the consump- tive use was 6.8 inches. The rainfall for the season was 12.43 inches and this was entirely lost by evaporation and transpiration since no run-off or deep penetration occurred. Plate XVII graphically shows the results on Plots HI and H2. PLATE XVII PLOT H,-IN ORANGE GROVE WITH HEAVY COVER CROP 4 .Rainfall stored in the soil Initial deficiency in the rooft zone.This must be replenished before deep penetration occurs PLOT H^ -BARLEY T 1 1 1 ! 1 1 1 II ■ ' R. infall stored in the soil i 1 (.;..: 1 : IT^T^-UJ. 1 1 1 ►5.84 7.03 7.36 9.49 10.2610.71 -Total rainfall to date in inches RAINFALL BY STORMS Depth of major root ~ "^ 3 a. ctivity- oranges and barley-' 5 ^ 4? 1 1 / — - storm total- ~^ I il ,r [ . il i J L .■,'#^?F?J 13.1* 13.1 „ 2 ~^ 13.2 £ 12.4 u it — 12.4 "■ 12.0 ■" ■- 6 6.0^ 60 1 fiO " % £■ 5o 8 - 6.0^ f „ » 10 6.0"- c ' 6.0 Oct. Nov. 1927 Jan. Feb. March April May 1928 STORAGE OF RAINFALL IN THE SOIL, PLOTS H-1 AND H-2, REDLANDS. ^*' ,-c >■ c^yi" %. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 65 CHAPTER IV CONSUMPTIVE USE OF WATER BY NATIVE VEGETATION ALONG STREAM CHANNELS Measurements on Temescal Creek. A rather unique opportunity for measuring losses of water by evaporation and transpiration from willows, tules and kindred moist land growths exists on Temescal Creek, four miles southeast of Corona. There are 12.8 acres of moist land on the canyon floor sharply outlined by a railroad grade along the east side and a road grade along the west side. The upstream end of the area is marked by an old, broken rock dam. Water is forced to the surface at this dam and flows on a very flat grade through a gap in the center. The outflow from the area passes under a bridge 2100 feet downstream from the dam, and again is confined to a narrow channel by the fills on each side of the bridge. There is no evidence of any seepage increment of water reaching the area studied from the rocky hills flanking it on the sides. The winters of 1927-28 and 1928-29 were seasons of scant rainfall and all growth outside the moist area was dry and brown at the time of the test. Even the slight depressions along the rocky hillsides showed no evidence of sub-irrigation. Plate XVIII is an airplane map of the area* made in June, 1929. The moist area as obtained from this map by planimeter measurements was found to be 12.8 acres. The method adopted for determining the rate of loss due to the moist land growth was to establish the inflow past the dam, the outflow past the bridge and the loss due to underflow. The difference between inflow and the sum of outflow and underflow was charged to evaporation and transpiration losses in the moist area. Plate XIX A shows the gaging station at the old dam. A six-inch Parshall flume was installed March 30, 1929, with a still well for measuring the upper head. Readings were taken from two to four times a week and a rating curve established for the Geological Survey recorder, t which recorded the water level in the still pool upstream from the flume. Some idea of the rapidity of plant growth at that time of the year may be had from the fact that it was necessary to clean out the tules, water cress and moss, both above and below this station, each week. Plate XIX B shows the gaging station at the bridge. A six-inch Parshall flume was installed here on April 2, 1929. A seven-day i-ecorder was installed on this flume to give a continuous record of the upper head. This station was visited twice each week. The test was started April 15, 1929, and continuous records were made until May 27, 1929, at which time the flow past the bridge dropped below 0.05 second-foot, ceasing entirely on May 29. * Photo by United States Army Air Service. t Gage height record furnished by courtesy of F. C. Ebert and H. C. Troxell of the United States Geological Survey. 5—81141 66 DIVISION OP WATER RESOURCES PLATE XIX »^i>U/;*-v TEMESCAL CREEK GAGING STATIONS. A. Control at Dam Showing Six-inch Parshall Flume and U. S. Geological Survey Recorder Shelter. B. Control at Bridge Showing Six-inch Parshall Flume and Recorder Shelter. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 67 0'-«OOOO^^i-HrH cq 00 O ■^ <: 1 c^ ^ t^ oo .-H oo J Oi r-H O I-" Ol » 1-. C^ T-l ^ ,-H ^ C cDoasioooosocvico-^co 0000-<*<10'^OCOO -r-OT-oc^ooooooi>- r'iOiOCOiO»OiX>OOOSO , ---OiOJOOOu^OOiOi .2-73 =3 a iCDOOCOOOO t-i W -•™ •s- , •a g « -5 S2, • S a." ■« z:. ; §^"> '< ^° ; g S o- a << 2. ' •2. » c, ' 0.150 ; i.570 0.28 0.176 ' .189 0.33 0.178 ' 237 0.33 0.188 i .475 0.35 0.220 . ).236 0.41 0.234 . >.570 0.44 0.259 ( ).165 0.48 0.290 1 902 0.54 0.298 r.093 55 0.298 r093 55 0.307 i:.m 0.57 0.278 1.617 0.52 0.268 i.379 50 0.267 3.355 0.50 0.297 r.069 0.55 0.298 7.093 0.55 0.318 7.569 0.59 0.330 r.855 0.61 0.353 ^.402 0.66 0.347 ? 259 0.65 0.343 M64 0.64 3.73 4 25 In Plate XXI C, the rate of use of water is shown to vary directly with the temperature of the air and to have the same time phase within rather close limits. The curves of stream flow in Plate XXI A have daily trends of maxima and minima similar to those of the transpira- tion-evaporation and temperature curves in Plate XXI C. However, the time of minimum stream flow occurs several hours later in the day than the time of maximum temperature and transpiration rate. This indicates a general lowering of the water plane over the moist area during the hours of maximum temperature. The time-lag of the hour of minimum stream flow behind the hour of maximum tempera- ture depends on the speed with which the general draft on the water table is compensated for by water from the stream channel. During periods of hot weather, the draft on the water table may not be entirely replaced by water from the stream channel within a 24-hour period. In that case the trend of the mean daily discharge of the stream is downward. * The automatic record from which the transpiration-evaporation curve in Plate XXI C was plotted was obtained by using a sensitive float valve feed from a supply tank to the willow and reed tanlt. The loss from the supply tank and the minute changes in water level in the willow and reed tank were recorded continuously on the same chart. The water level in the willow and reed tank was maintained three inches deep over the soil surface. 70 DrVISION OF WATER RESOURCES PLATE XX TEMESCAL CREEK SWAMP TANKS. A. Tank A (right) and Tank B (left), June, 1930. B. Tank B at Ontario in July, 1930. IlAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 71 < ^ < r ) < > r ^ > < > < > r > c > r > ii> 1 > > a. ? o < ^ c > > \ > o c > < ^ \ c i c p3 — f i> rr > r > ^ f > > r 1 > ^J> ( < 1 ( > < :? > > ) ^ ^ < > c f ) < > : <^ < • ^ ( c^ * r > (' > s 5 s- ^ ~ ' ">" ~s "I -5 1 's -^ -d 1" ~ 1 ~ 3 ^ *^ 1 V ^ ^ k 5. S- E ^ i ^.^ "! _z I > I '- 11 ^^ ^ '^ "o "^ ) a. * ^ 5" ^1 ^ '^ f d ° ~ 1 — C^ ° 1-6 ^ S 9 3 s t >^ -: g i -- ^ M -= 3 't- - s s . "5 i ■-- •2 '-< > < ^ ^ 'S n < ■) ^ oc •^ ft < -J ^; > < —t <:: "^ < — > <: c; -> -:: 1 <: ' < -> <; p < — 0000 Oi < H Z (SI O ^< U CO 3 W H hJ < < « W Oh "s w < w 2 Xepjadajoejad saqoui-ajDEJoqidap saL|DU! Ul sso"| ;aa>puoD3S MOI^UISSOT f*E 11 E S u. -oO •< •5 2 ■s ■< >-§ 1^ 72 DIVISION OF WATER RESOURCES TABLE 34 MONTHLY LOSS OF WATER BY EVAPORATION AND TRANSPIRATION FROM TANKS A AND B AT TEMESCAL CREEK AND ONTARIO October, 1929, to August, 1930 Date Location •Tula Tank A, loss per month in inches 'Willow and Reed TankB. loss per month in inches 1929— October Temescal Creek Temescal Creek _ - Temescal Creek Temescal Creek Temescal Creek Temescal Creek Temescal Creek, -.-.-- Temescal Creek 16.79 9.15 4.83 3.91 2.74 4.82 11.53 14.33 6.64 5 52 December.-- 1930— January February 3.81 4.23 2 95 4.61 9.19 14 37 18.45 July 29 60 Ontario 30 67 • Tules planted in Tank A, August 24, 1929. ■ Tank B planted to willows Augiist 26, 1929, but swamp grass and reeds gradually possessed the tank until by March. 1930, the willows were but a minor portion of the growth in the tank. Tank B was moved to Ontario on June 4, 1930 1 TABLE 35 WEEKLY LOSS OF WATER BY EVAPORATION AND TRANSPIRATION FROM TEMESCAL TULE TANK A October, 1929, to June, 1930' Week ending Loss per week in inches Week ending Loss per week in inches 1929— October 7 4.40 3.57 3.54 4 02 2.95 2.40 2.22 1.86 1.36 0.97 0.98 1.15 1.16 1930— January 6 1 36 October 14 1.36 October 21 0.67 October 28 44 November 4 February 3 February 10 February 17. February 24 March 3 -.. . 0.45 0.73 74 0.69 70 March 10.. 0.70 March 17 0.71 December 23 March 24 . 72 December 30 March 31 2.39 April 7 1.76 April 14 2 27 April 21 3.17 April 28 . - 3 17 May 5 2.96 May 12 2.26 May 19 2 63 May 26.. June 2 4.08 4.56 ' Tules planted in tank August 24, 1929. It may then be stated that tlie moist land growth bordering a stream channel such as Temescal Creek has a marked influence on the f ow of the stream. There is a daily fluctuation in flow to meet the traispira- tion demands of the bordering plant growth and a seasonal decrease in flow as the transpiration rate increases. The peak demand of trans- piration on the "water of the stream may be expected in July and August. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 73 Air temperature is shown to be a direct indicator of tlie transpiration rate and hence of the stream flow. High temperatures cause extremely high rates of transpiration and correspondingly low stream flows. This loss may be largely prevented by carrying the streams in lined canals or pipes and by lowering the water table bj'- pumping in areas of rising water during the period from Maj^ 1 to October 1. Probable Limits to the Losses Along Stream Channels. The indicated loss of 12.9 inches in 30 days at Temescal Creek, together with still higher rates of loss from small isolated tanks of swamp growth, has led to a consideration as to what the probable limits for losses in moist areas along stream channels might be. The radiant energy received from the sun, or insolation as it is termed, suggests certain upper limits to the amount of water that may be vaporized over large swamp areas. Average daily records of insolation are published in the Monthly Weather Review for stations at La Jolla, Pasadena and Fresno. The equivalent water of vaporization for the insolation received at Pasadena and Fresno for the calendar year 1929 is as follows : Station Total annual insolation' Equivalent water of vaporization at 68 degrees Fahrenheit Gram calories per square centimeter 165,416 169,691 Depth in feet 9.27 Fresno 9.51 9.39 ' Direct plus diffuse received on a horizontal surface. This suggests that, if all of the radiant energy received from the sun were used in vaporizing water, it would be possible to lose 9.39 acre- feet per acre annually, as an average for the two stations, as the result of insolation. Using the Fresno records for the period April 28 to May 27, 1929, we have the insolation as 20,467 gram calories per square centimeter and the equivalent water of vaporization at 68 degrees Fahrenheit as 13.8 inches. This is for the same period that the indicated loss from the swamp on Temescal Creek was 12.9 inches. It is likely, then, that the rate of loss was approaching its probable maximum when the tests on Temescal Creek ceased, due to a failing water supply late in May. There is some additional supply of heat to the swamp area from the surrounding rocky canyon walls and from the strong draft of air flowing through the canyon. On the other hand, not all of the insola- tion received directly on the swamp area is used in vaporization. Some of the radiant energy is stored in combination within the plant tissues, some is reflected from the plant surfaces and part goes into heat storage and in part is again radiated back to the sky. The discussion of the receipt of energy, other than the vertical com- ponent from the sun, leads to a consideration of what the effect might be on very small patches of swamp growth. The extreme case may well be considered as an isolated tank of swamp growth two feet in diameter set in otherwise barren ground. The radiant energy inter- cepted by the plant growth in the tank must necessarily be a greater 74 DIVISION OF WATER RESOURCES amount than the same area of growth in a swamp would receive because the isolated tank growth has a side exposure that in a swamp would be protected by surrounding plants. The analogy that might be drawn is that of a lens focusing the sun's rays on the restricted area of the tank. Take the case of the two-foot tank used at Ontario in studying the correlation between air temperature and transpiration. The loss for the month of August, 1930, from the Ontario willow and reed tank was 30.67 inches depth. This is about two and one-half times the depth of water that could be vaporized by the insolation falling on the horizontal area of the tank. A partial explanation is that the tall growth in tlie isolated tank intercepts a much larger amount of insola- tion than the same area of growth would receive in a swamp. But in the case of the small tank, the heat energj- brought to the growth in the tank by air movement also is relatively large. An experiment inves- tigating this point was performed at Ontario on August 22, 1930. On this date, the willow and reed tank was shielded from the direct rays of the sun by a corrugated iron roof, eight by ten feet, placed just high enough to clear the plants and allow free lateral wind movement. The record of water loss is shown in Plate XXIC. The full line on August 22 is the actual loss with the tank shielded. The dotted line is the average of August 21 and 23. The values are : Loss August 21 1.296 inches Loss August 23 1.274 inches Average loss for August 21 and 23 1.2S5 inches Loss August 22 0.77S inches (with tank shielded) The heat supply for vaporizing this 0.778 inches of water on August 22 must have come almost entirel}^ from the moving air currents passing through tlie growth in the tank. However, when a large SAvamp area is considered, there must be a rapid drop in temperature of the air as it passes through the swamp growth if it is to give up its heat supply at the rate indicated by the above experiment. As soon as the air is cooled to the same tempera- ture as the plants there can be no further transfer of heat from the air to the plants. When this condition is reached, the energy for vaporization must come solelj^ from insolation. It may be expected, then, that small isolated patches of swamp growth will show rates of loss per unit area higher than that accounted for by insolation alone, but it also is probable that the loss from an extensive swamp area is limited to a value not widely variant from that indicated by insolation. The inference is that in conducting tank work to gain data for use in estimating losses from field areas, that the tank should be set in a field of growth similar to that in the tank and the outside growth must completely surround the tank so the exposure of the growth in the tank is normal. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 75 CHAPTER V AREAS OF IRRIGATED LAND Land in the Santa Ana River area cropped during the summer is generally irrigated, although some deciduous orchards and vineyards are exceptions to the general rule. All citrus crops within the area require irrigation, but the amount of water applied varies widely, being dependent on the immediately available supply. In the basins having the least water, the amount applied on citrus land is quite often insufficient to moisten the entire root zone. As a result, there is an increasing soil moisture deficiency as the summer season progresses, and the groves in such basins enter the winter season with a relatively dry root zone capable of absorbing a large portion of the winter rainfall. On the other hand, in basins having a surplus of water, citrus crops may be heavily irrigated so that the root zone is then relatively moist when the rains come and a considerable portion of the rainfall percolates through the root zone and reaches the underground water table. Deciduous orchards and vineyards are usually handled in such a manner as to retain much of the winter rainfall within the root zone. There is generally a large soil moisture deficiency in the fall of the year, and, where irrigation is practiced during the dormant season, it is usually delayed as long as practicable in the hope that there will be sufficient rain to thoroughly moisten the root zone. The disposition of rainfall in cultivated areas is described in the following pages. Citrus Orchards. Ehert Plots. — The Ebert plots, A and B, are located in a mature Navel orange grove. The soil t^'pe is Hanford fine sandy loam to a depth of five feet and is fairly free from rock to that depth. The soil type was the major factor in the selection of this grove for study as over 2000 soil samples are required annually from each plot in order that accurate determinations regarding the disposal of rain and consump- tive use of water can be made. Each plot consists of a square of four trees, and seventeen definite points of sampling are located within the square. Sets of samples are taken at intervals of from ten days to two weeks. For an absolute check on the winter transpiration by citrus, a cover plot was established in this grove after the rainfall was sufficient to fill the soil within the root zone to field capacity. By preventing rain from falling on the plots, except as desired, the amount of moisture in the soil was controlled, and thus more reliable data were obtained from soil sampling. An oiled canvas was placed on a framework beneath the tree branches at one four-tree square so that the soil was protected from rain within and to a distance of eight feet beyond each 76 DIVISION OF WATER RESOURCES side of the square. Plate XXII is a photograph of this plot. Soil moisture records then were kept without interference from the fre- quent rains. A record of soil moisture extraction in one-foot sections down to a depth of six feet was kept for this plot throughout the year. The results showing use of water by transpiration are summarized in Tables 36 and 37. Plate XXIII is a graphical presentation of the results from Plot A for 1928-29. Tables 38 and 39 show the disposal of rain for 1928-29 and 1929-30 seasons. Holden Plot. — The Holden grove of mature naval orange trees is located in the Arlington district West of Riverside. An excellent record of winter rate of tranpiration was obtained from Plot E in this grove PLATE XXII TRANSPIRATION FROM CITRUS TREES DURING RAINY SEASON. PLOT IN EBERT GROVE. FEBRUARY, 1929. COVERED between November 25, 1929, and January 3, 1930. The rate for this 39-day period was found to be 1.41 acre-inches per acre per 30 days. The greatest deficiency in soil moisture during the winter occurred just prior to the start of the January rains when the indicated defi- ciency was 3.09 acre-inches per acre below field capacity. This value includes the deficiency in the soil mulch. The amount and distribution of the rain for 1929-30 were such that it all was held within the root zone until May 1. The grove was very heavily irrigated on April 26-30 so that when the early May rains started the soil was very wet. Due to the heavy rains added to the excessive irrigation, the soil below the second foot was still above field capacity on May 15, ten days after the end of the rain on May 5. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 77 - 400J xs\ jooj puj looj -pje jooj "Mit iooj ms »j3e jad Uj-Dv O'V C] >. Ijos J.0 ioo; Ljoea jo^ sa?Piu9DJ9d 9jnisio|^ sagouiui ||e^uiBj sXepofjadDejaduioeui JO uoneSij j| 8jn;s!0UJ jios p asn jo a^ey 78 DIVISION OF WATER RESOURCES TABLE 36 MONTHLY TRANSPIRATION USE OF WATER >-EBERT GROVE, PLOT A MATURE NAVEL ORANGE TREES July, 1928, to June, 1930 Use of water in acre-inches per acre Month 1928 1929 1930 0.80 0.72 1.05 1.36 1.63 1.92 1.02 1.13 1.09 1 40 1.40 July 3.01 2.86 2.25 1.74 1.43 0.95 ' The "transpiration use of water" is the actual amount of water extracted from the soil by root action and is mainly transpiration. The loss by evaporation from the four-inch loose soil mulch is not included in these figures. TABLE 37 MONTHLY TRANSPIRATION USE OF WATER— EBERT GROVE, PLOT B MATURE NAVEL ORANGE TREES March, 1929, to June, 1930 Month Use of water in acre-inches per acre 1929 1930 1.29 1.16 i.74 1.72 2.22 2.81 '3.28 3.15 1.91 2.16 1.53 1.35 1.50 1.95 2.09 ■2.18 'Total use July 1, 1929, to June 30, 1930, 23.55 acre-inches per acre. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 79 TABLE 38 DISPOSAL OF RAINFALL— EBERT GROVE, PLOT B MATURE NAVEL ORANGE TREES Season of 1928-29 o H > ^ a f > c:^ 13 IT 1 o E^ 2,8 11- li'^' 3-ri 111 •-1 cT =3 2. 5" o •^S^ 5' c §^1 3 O 3*3 3 5" 5" 5' ^,5 a « If a i S B o-a o 2.S 5-J 5' cr §•0 a. 1 o- ^"^ TO 2. N? 2, ^ 1 S" 2 o 1 era (D 5'S g-? o 1929— 6.19 8.01 2.07 1.34 Jan. 27_.__ 1.82 0.73 0.73 0.34 0.02 0.00 0.02 Feb. 9 9 09 1.08 0.98 0.36 0.43 0.28 0.01 0.00 0.01 Mar. 6--_ 9.86 0.77 1.88 —0.90 0.97 0.70 00 0.00 0.00 Mar. 16... 12.74 2.88 ■+0.14 2.02 0.56 20 0.10 0.00 0,10 April l.._ 13 12 0.38 0.89 —1.03 0.90 0.38 0.00 0.13 0.13 April 16__ _ 15.05 1.93 0.57 32 0.84 0.67 0.00 0.10 O.IO April 29... May 1S 15 05 00 1 34 —0 77 0.77 -- 0.00 0.00 0.00 15.05 0.00 2.16 —0.82 82 0.00 0.00 0.00 ' Surcharge was in second and third feet. TABLE 39 DISPOSAL OF RAINFALL— EBERT GROVE, PLOT B MATURE NAVEL ORANGE TREES Season of 1929-30 ( O 1 o 5. 3 1 p 5' s- i: 5' 5* cr > 2,0 p 3 ll. 3 2. .-.3 3 g s 1 ' a. ; p_ CO tJ* o 3 C :> 3 TO j|. ?^ 2 o 4 3 o .-^m P 3'o^i. S p B 0-3 ; TO 3 s-p? p 3 il •0,0 3' TO 2. B'S > ill "" 2 -T a| £.65 p, i" 3 =s 5' 3" r.3 < 0* |p. I'i li 1 ■a ■a a ? 1< Oct. Oct. Oct. Nov. Nov. Dec. Dec. Dec. 1 Jan. ., Feb 29— 3 0.55 2.41 7' 8 1.53 3.26 .91 1.93 2.51 .00 0.14 1.13 1.20 .42 1.72 1 58 3.17 0.88 —1.73 2.35 —1.02 — .58 2.51 —0.14 — .99 — .07 .78 —1.30 .14 —1.59 1.15 1.74 .53 .97 .63 .24 1.12 1.12 .33 1.62 1.30 1.89 1.59 9' 20 10 23 28' )30— !5._-- 51 6.50 7.22 7.89 12.73 5.95 .72 .67 4.84 0.37 .59 .41 1.14 0.13 4.47 .00 .00 1.24 .00 .00 .00 4.60 Mar < 'O6' April April May June 3... 23 1.30 22.... 13 15.56 2.83 .80 Totals 15.56 5.90 ' Irrjgated. ' Irrigated, 3.5 acre-inches per acre. 80 DIVISION OF WATER RESOURCES The excessive irrigation prevented an accurate determination of the disposal of the May rains, but the saturated soil condition on May 15 indicated a deep penetration below the root zone for both rain and irrigation water. Woodhridge and Buchanan Plots.— After development of the com- pressed air unit for driving the soil tubes and the soil tube jack for pulling the tubes it was possible to do intensive work in the rocky soils of the Ontario-Upland district. Accordingly, in the fall of 1929, a plot was established on the Woodbridge grove in Upland and one on the Buchanan grove in Ontario. The disposal of rain for the season of 1929-30 on the Woodbridge plot is shown in Table 40 and for the Buchanan plot in Table 41. TABLE 40 DISPOSAL OF RAINFALL— WOODBRIDGE PLOT- MATURE LEMON TREES Season of 1929-30 'Note — No surface run-off. Total penetration below su-foot level in unirrigated section along tree line, 3.08 inches. Total penetration below six-foot level in irrigated section, 8.49 inches. Average equivalent penetration below six-foot level over entire plot, 6.57 inches. H > 5P f-, > »TJ -1 o-B P o 30.2. 3 p s'p'w 5-oB 1-1° "3 Date of soil sampling 3* o a. 5' £ 2, B r •Op 5' 5' 5'|- 5' c 5-p3 rli; S;P D 5' 0^9. g'SB p 3 g 11 II 5'cr ? ° 1 o- P" — "?■< I'll „ ^-t =? PI i§ : 5-^ 1 TO a a' a s-v ^ Unirrigated section along tree line (40 per cent of area) 1929- 0.51 4.86 1930— January 18 7.83 7.32 -1-0.13 4.99 1.53 0.70 0.10 Irrigated section (60 per cent of area) 1929- 0.51 0.51 2.31 2.66 December 21 —0.35 0.35 0.00 0.00 1930— 0.51 7.83 0.00 7.32 0.14 -1-0.95 -1-2.52 -fl.09 0.50 0.62 0.00 0.70 0.00 4.91 Whole plot February 19 8.35 0.52 1.12 —2.17 1.33 0.52 0.84 March 28 13.78 13.95 18.74 5.43 0.17 4.79 0.46 1.89 0.33 -1-0.66 —1.43 -1-1.56 1.73 1.43 1.73 1.00 0.17 0.80 2.04 April 23 0.00 May 19 - 0.70 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 81 TABLE 41 DISPOSAL OF RAINFALL— BUCHANAN PLOT MATURE NAVEL AND VALENCIA ORANGE TREES Season of 1929-30 Date of soil sampling Unirrigated section along tree line (40 per cent of area) 1929— December 10 December 27 1930— January 18 Irrigated section (60 per cent of area) 192^- December 10 December 27 1930— January 18 Whole plot February 19 March 28 April 23 May 20 0.62 0.62 0.62 0.62 6.65 13.37 13.54 16.76 5.36 5.36 0.67 6.72 0.17 3.22 '~'o t^' 5'p <= 5o 2.84 3.42 +0.81 0.26 1.58 +1.99 1.09 +0.02 1.97 1.16 O fD 2 3 Is" 5'o 2. erg o —0.58 +4.23 —1.32 +3.57 —3.08 +1.11 —1.99 +0.81 a s= gg 3 S-. 0.58 0.43 1.32 0.74 1.07 1.37 1.99 1.42 ;-g 3 0.00 0.70 0.00 0.70 0.60 1.00 0.17 0.80 0.00 0.00 0.00 0.35 3.24 0.00 0.19 •Note — No surface run-o£F. Total penetration below six-foot level in section along tree line, 3.43 inches. Total penetration below six-foot level in regularly irrigated section, 5.86 inches. Average equivalent penetration below six-foot level on entire grove, 4.89 inches. Comparison of Penetration of Bainfall in Citrus Plots. — Summarizing the results for 1929-30 for the three citrus plots on which quantitative data were obtained for the deep penetration below the root zone, we have : Plot Season Rainfall in inches Penetration below root zone in inches Ebert-. 1929-30 1929-30 1929-30 15.56 18.74 16.76 5.90 6.57 4.89 Both the Ebert grove and the Woodbridge grove were irrigated late in December, so there was very little deficiency in soil moisture when the January rains started. The Buchanan plot had a deficiency of 1.9 acre-inches per acre in the irrigated section at that period and this plot shows the lowest value for deep penetration below the root zone. A thorough inspection of the soil moi.sture conditions in citrus groves of the Santa Ana River area in May, 1930, showed all of the root zone thoroughly moistened. This is evidence of a general contribution of rainfall to the ground water supply by direct penetration of moisture through the root zone. 6—81141 82 DIVISION OF WATER RESOURCES Deciduous Orchards. Walline Plot. — The Walline peach plot is located in an orchard four miles east of Ontario. The soil is a uniform Hanford sand to a depth of fifteen feet, and below this depth it is somewhat silty with occa- sional gravel pockets. The peach variety is Tuscan Cling and the trees were set out in 1916. Irrigation in this grove is accomplished with the furrow and cross- check system. The standard orchard plot method of soil sampling was used with seventeen points of sampling within the square of four trees. Table 42 shows disposal of rain and Table 43 the use of water throughout the year. TABLE 42 DEFICIENCY OF SOIL MOISTURE AND DISPOSAL OF RAINFALL— WALLINE PLOT TUSCAN CLING PEACHES Season of 1928-29 > o > H H H V Date of soil sampling o 3 w C ■2.2, m §. ||5- r||. S'c" TO g 3.0'S- 5' a. 5" 3 3^ ?l § £. S g. C_3 re li ft 5'2, S'g cr3 s — — c w^ si S'o. Cm B rt. S-S- '. "< , a. ' S- li &•? i a 0. '< cr i ?■ 1928— Initial fall deficiency 13.85 November 21 1.54 2.38 0.56 1.49 0.98 0.89 1.54 3.92 0.56 2.05 0.98 1.87 13.29 December 28 _- 11.80 1929— January 23 1.93 1.43 50 5.85 3.48 2.37 10.37 February 28 1.38 1.23 0.15 7.23 4.71 2.52 9.14 April 8 . - 3.79 2.55 1.24 11.02 7.26 3.76 6.59 TABLE 43 USE OF WATER-^WALLINE PLOT, TUSCAN CLING PEACHES, ONTARIO, 1928 1928 Transpiration use in acre-inches per acre' 1928 Transpiration use in acre-inches per acre' January 0.0 5 3.0 6.2 July... 8.0 6.0 March . - . September October 2.7 0.9 May. 0.2 June December.. 0.0 1 From upper fifteen feet of soil. Transpiration, total for year 27.5 inches Evaporation, winter rains 4.3 inches Evaporation, irrigation 2.0 inches Total atmual evaporation-transpiration 33.8 inches Rainfall Pe^ietraiion Tests hy Inspection. — General soil moisture sur- veys were made by crops at the end of the rainy reason in 1929 and again in 1930. Usually the depth of rain penetration could be deter- mined from an examination of the soil tube cores as the soil would be RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 83 distinctly dry below the depth of the seasonal moisture penetration. If no dry soil was found, borings were made to depths of twelve, fifteen or eighteen feet, depending on the crop, and the notation "no dry soil" recorded. Deciduous orchards irrigated in the late fall or winter were generally moist to the full depth of the root zone. Nonirrigated orchards in poor condition due to lack of care or poor soil were found to be relatively shallow rooted, while the more vigorous orchards and vineyards showed root activity to fifteen and eighteen-foot depths. This was indicated by dry soil at such depths. The records for the 1928-29 and 1929-30 seasons are given in Tables 44 to 49, inclusive. TABLE 44 PENETRATION OF RAINFALL IN PEACH AND APRICOT ORCHARDS AS DETERMINED BY FIELD INSPECTION Season of 1928-29 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 2 ..... April 24, 1929 April 24, 1929 April 24, 1929 April 25, 1929 April 25, 1929 April 25, 1929 April 25, 1929 April 26, 1929 April 26. 1929 April 26, 1929 April 26, 1929 April 26, 1929 April 26, 1929 April 24, 1929 April 26, 1929 April 26, 1929 April 26, 1929 April 26, 1929 11.07 11.07 11.07 11.07 11.07 11.07 11.07 11.07 11.07 11.07 11.07 13.13 13.13 11.07 13.13 13.13 13.13 13.13 9.5 3 5.3 4 9.0 5 7.5 6 7 8 10.0 9.3 9 8.3 10 No dry soil 11 7.2 12 No dry soil 16 . . 8.5 18 7.2 Tests in irrigated areas 1 13 14 15 No dry soil No dry soil No dry soil No dry soil 17 8.5 TABLE 45 PENETRATION OF RAINFALL IN VINEYARDS AS DETERMINED BY FIELD INSPECTION Season of 1928-29 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 2 May 4, 1929 May 4, 1929 April 26, 1929 May 4, 1929 May 4, 1929 11.39 11.39 11.07 11.39 11.39 7.2 4 6.8 Tests in irrigated areas 1 No dry soil 3 6.2 5 No dry soil ij 8d DR^ISION OF WATER RESOURCES TABLE 46 PENETRATION OF RAINFALL IN WALNUT GROVES AS DETERMINED BY FIELD INSPECTION Ssason of 1928-29 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 13..,. 14 18 May 2, 1929 May 2, 1929 May 2, 1929 April 27, 1929 April 27, 1929 April 27, 1929 April 27, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 May 2, 1929 13.13 13,13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 13.13 4.5 5.5 5.5 Tests in irrigated areas 1 4.5 2 . . . 5.0 3 5.5 4 9.0 5 .. 11.0 6 7 - - . -- No dry soil 12.0 8 14.0 9 12.0 10 . - No dry soil 11 14.0 12 No dry soil 15 No dry soil 16 _ . . - No dry soil 17 No dry soil TABLE 47 PENETRATION OF RAINFALL IN PEACH AND APRICOT ORCHARDS AS DETERMINED BY FIELD INSPECTION Season of 1929-30 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 19 April 14, 1930 April 14, 1930 April 14, 1930 April 14, 1930 April 14, 1930 April 14, 1930 April 14, 1930 April 14, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 14, 1930 April 14, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 April 15, 1930 9.16 9.16 9.16 9.16 9.16 9.16 9.16 11.95 13.54 13.54 12.32 12.32 12.32 12.32 12.32 11.95 13.54 13.54 12.32 12.32 12.32 12.32 12.32 12.32 12.32 12.32 13.54 13.54 4.0 20 4.0 21 3.5 22 3.3 23 4.0 24 7.5 25 6.0 27 No dry soil 29 . 8.5 30 10.0 33 7.0 34 9.0 35 6.0 37 6.0 41 5.4 Tests in irrigated areas 26 . No dry soil 28 -- - 31 - No dry soil No dry soil 32 No dry soil 36 No dry soil 38 No dry soil 39 No dry soil 40 No dry ."oil 42 No dry soil 43 No drv soil 44 No dry soil 45 No dry soil 46 11.5 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 85 TABLE 48 PENETRATION OF RAINFALL IN VINEYARDS AS DETERMINED BY FIELD INSPECTION Season of 1920-30 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 9.. 10.. 11-. 12.. Tests in irrigated areas April 17, 1930 April 17, 1930 April 17, 1930 April 17, 1930 April 17, 1930 April 17, 1930 April 17, 1930 April 17, 1930 12.32 12.32 12.32 12 32 12 32 12.32 12.32 7.0 8.0 6.2 No dry soil ■ 5 8.0 8.0 No dry soil May 9, 1930 May 9, 1930 May 9, 1930 May 9, 1930 May 9, 1930 May 9, 1930 15.70 15.70 15.70 15.70 15.70 15.70 8.2 8.0 8.2 9.0 9.3 9.0 TABLE 49 PENETRATION OF RAINFALL IN WALNUT GROVES AS DETERMINED BY FIELD INSPECTION Season of 1929-30 Hole No. Date of sampling Total rain to date in inches Depth of penetration in feet Tests in unirrigated areas 22 May 16, 1930 May 16, 1930 May 16, 1930 May 16, 1930 May 16, 1930 May 16, 1930 14.73 14.73 14.73 14.73 14.73 14.73 6.5 Tests in irrigated areas 19 5.0 20 No dry soil 21 No dry soil 23 :.. No dry soil 24 No dry soil Alfalfa. Thomas Plot. — The alfalfa plot is located on the Thomas ranch, three miles southeast of Chino. The soil is a Hanford sand to a depth of four feet, shading into a silt loam at seven feet, and is quite sandy again in the thirteenth foot. Irrigation is accomplished by flooding with the aid of portable slip-joint pipe. The plot is 48 feet square and six points of sampling are located eight feet apart across the center of the plot. Intensive sampling with- out disturbing the crop is accomplished by working from portable wooden horses. None of the 1930 summer irrigation water penetrated to the twelve- foot level on the plot, and it is probable there was a considerable deficiency in soil moisture at the beginning of the rainy season. This, of course, will depend on the amount and time of fall irrigations. The rate of use of water from May to August, 1930, is shown in Table 50. 86 DIVISION OF WATER RESOURCES TABLE SO CONSUMPTIVE USE OF WATER— ALFALFA PLOT, THOMAS RANCH, CHINO, 1930 Dates of irrigation May 26. July 12. Aug. 6. Sept. 12. Dates crop was cut May 12.. July 18. Aug. 21. Period studied May 12-May 23. June 7-July 1. July 21-Aug. 4. Rate of use in acre-inches per acre per 30 days 4.03 5.50 '3.54 ' Crop was cut July 18. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 87 CHAPTER VI 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 being studied. During the summer months the capillary moisture is more or less completely withdrawn from the soil within the root zone by the processes of evaporation and transpiration. In non- irrigated soil the moisture content may be depleted until little more than hygroscopic water is left, 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 pene- tration 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 sup- plied with its field capacity. The moisture content of the soil at the beginning of the rainy season varies with the last crop raised, type of soil, amount of irrigation water applied, evaporation, transpiration by plant life, depth of water table and other conditions. 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 greater moisture deficiencies. The initial fall deficieny in moisture content of the soil is determined 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. Summary of Plots. — The deficiency of soil moisture below field capacity at the beginning of the rainy season for the various experimental plots heretofore described is summarized in Table 51. The initial fall mois- ture deficiency for any particular plot may be considered a fairly definite amount for unirrigated lands, but for irrigated areas, especially citrus, the amount is variable, depending upon the irrigation practice. Citrus and Walnut Plots, Orange County. — During the years 1927 and 1929, S. H. Beckett, Division of Irrigation Investigations and Practice, University of California, conducted a cooperative investigation in Orange County on the use of water by citrus and walnut trees. From the result of these studies, the following tables have been compiled : 88 DIVISION OF WATER RESOURCES TABLE 51 SUMMARY OF INITIAL FALL MOISTURE DEFICIENCY FOR VARIOUS PLOTS Location Crop Soil type Initial fail moisture deficiency of .soil below field capacity in inches Devil Canyon shaft Muscoy Plot I Muscoy Plot J --- Palmer Canyon Plot K. PlotB2 PlotB3 PlotB4 PlotB5 PlotB6 PlotB7 PlotBS Devil Canyon Plot B... PlotAl PlotA2 PIotDl Plot El — PlotE2 PIotF. PlotH2 EbertPlot A (September 23, 1928). (October9, 1928)...- EbertPlotB (Octobers, 1929).--- (December28, 1929)' HoldcnPlot Woodbridge Plot (■December 13, 1929)' (Januarys, 1930)'-- Buchanan Plot (December 27, 1930)' Plot HI WallinePlot PlotGl PlotG2 Brush Brush Brush Brush Brush Brush Brush Brush Brush Brush Brush Weeds and grass Weeds and grass Weeds and grass Weeds and sunflowers Grass and weeds Grass and weeds Grass and weeds Barley Citrus Citrus Hanford gravelly sandy loam- Hanf ord gravelly sand Hanford gravelly sand Plaoentia clay loam Hanford stony sandy loam Hanford gravelly sandy loam- Tuiunga stony sand Tujunga stony sand Hanford stony sandy loam — Hanford gravelly sandy loam- Hanford stony sandy loam Hanford gravelly sandy loam- Hanford fine sandy loam Hanford fine sandy loam Hanford sand Hanford sand Hanford sand Hanford loam Placentia loam 12.5 9.0 8.1 10.1 11.1 10.0 11.9 8.0 14.0 11.3 11.1 6.9 5.8 4.6 13.2 7.6 6.0 7.1 4.3 Hanford fine sandy loam. Hanford fine sandy loam- Citrus Citrus Citrus Citrus Peaches Peaches Peaches Hanford loam ^- Hanford gravelly sandy loam. 2.9 '0.0 3.1 Hanford gravelly sandy loam- Placentia loam 2.5 '0.6 Hanford sand.- Placentia loam- Placentia loam- 2.1 3.4 14.3 8.2 8.5 ' Prior to major rains. 2 Grove had been recently irrigated. TABLE 52 DEFICIENCY OF SOIL MOISTURE IN CITRUS GROVES, ORANGE COUNTY, 1928 Deficiency of soil moisture Depth of sample in feet Station 17A Station 17B Station 19A Station 196 Station 20A Station 21A Station 21B October 10 October 10 November 8 October 22 October 22 October 26 October 25 0-1 In inches' 0.99 1.29 1.33 1.31 1.21 1.09 In inches' 1.21 1.92 2.38 2.60 2.43 1.94 In inches' 1.14 2.33 3.01 3.45 3.68 3.92 In inches' 0.84 1.69 1.82 1.91 2.02 2.02 In inches' 0.86 2.06 2.43 2.72 2.83 2.76 In inches' 0.21 0.60 1.01 1.50 1.06 2.09 In inches' 0.02 1-2 0.54 2-3 -- 1.00 3-4 1.49 4-5 1.63 5-6 1.72 > Total to bottom of section. Tables 52 and 53 show the deficiency of soil moisture for citrus plots on various dates in the fall, and Tables 54 and 55 show the maximum deficiency of soil moisture permissible under good irrigation practice on RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 89 O M I-) « o 10 CO 00 •'t* 10 CO «ooci ci c^ N J g. a 02 M 10 c ^ s --1 "-l »- --l J3 -g a .s rf i d ^ xn Q s ■^ OS-^OO t^o Q ^ C^ a 1 2 S 2; 1 00 00 ^ »-< C<1 t^ OS ^ (M -"S* -^ CO r^ ■3 "0 05 1 1 _d 000000 g" J S d cc P 03 CO CO CO 1-^ CO (M „ 000 CO to 0.00 03 1 .a T^^cicic^cn .S ■| > d m z 00-HC0 00050 Q « ooooo^co ^_, S ^^^c^ccieo 1^ a5 S — irt cqccic^ci *"• ^ ,J3 13 .2 d 02 > d <33 urs t^ >o 00 03 _ CO -* >0 CO to j_j S T-H ^ 1-1 T-* ^H c M -d "cl a .3 d ra a 00 030 05t^ t^ tn „ ^ 03 CO CO >o to t^ fli S ,-< ^ cd e a :9 m Z »-< a 0— • ^^ s -e 0. &£ «g TV??'?? ■-< IM CO •>!< 90 DIVISION OF WATER RESOURCES the basis of root distribution. Tables 56 and 57 give similar informa- tion for walnuts. These values for soil moisture deficiency are for the wi root zone below the loose soil mulch. f TABLE 54 ; MAXIMUM DEFICIENCY OF SOIL MOISTURE UNDER GOOD IRRIGATION PRACTICE ON BASIS OF ROOT DISTRIBUTION FOR CITRUS, ORANGE COUNTY, 1928 Depth of sample Deficiency of soil moisture in feet Station 19A Station 19B Station 20A Station 17A Station 17B Station 21 A station 21B 0-1 In inches 1.58 1.34 .52 .48 .33 .25 In inches 1.61 1.32 .27 .31 .22 .07 In inches 1.69 1.72 .64 .54 .10 .06 In inches 1.39 .46 .23 .13 .02 .02 In inches 1 55 1 35 .60 .36 .07 In inches 1 37 .75 In inches 1 09 1-2 .55 2-3 3-4 4-6 .23 .22 5-6__ .15 .24 Totals 4.50 3.80 4.75 2.25 3.93 2 50 2.10 TABLE 55 MAXIMUM DEFICIENCY OF SOIL MOISTURE UNDER GOOD IRRIGATION PRACTICE ON BASIS OF ROOT DISTRIBUTION FOR CITRUS, ORANGE COUNTY, 1929 Deficiency of soil moisture Depth of sample in feet station 19C Station 19D Station 20B Station 17C Station 17D Stations 21 AandB 0-1 In inches 1.46 1.27 .49 .42 .16 .10 In inches 1.51 1.32 .51 .44 .20 .12 In inches 1.73 1.59 .46 .42 .08 .15 In inches 1.50 .42 .10 .06 ioi In inches 1.53 .46 .18 .05 .02 .02 In inches 1.20 1-2 _-- .94 2-3 .45 3-4 . . .44 4-5 .20 5-6 --- .07 Totals 3.90 4.10 4.43 2.09 2.26 3.30 TABLE 56 DEFICIENCY OF SOIL MOISTURE IN WALNUT GROVES, ORANGE COUNTY Deficiency of soil moisture Depth of sample Station 18A Station 18B Station 18C Station 18D November 10, 1928 November 10, 1928 November 6. 1929 November 6, 1929 0-3.. -. In inches' 5.34 10.26 12.90 In inches' 5 34 10.86 15.06 In inches' 5.04 8.64 10.89 13.05 In inches' 4.20 3-6 6.54 6-9 9 39 9-12 11.01 I Total to bottom of section. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 91 TABLE 57 MAXIMUM DEFICIENCY OF SOIL MOISTURE UNDER GOOD IRRIGATION PRACTICE ON BASIS OF ROOT DISTRIBUTION FOR WALNUTS, ORANGE COUNTY, 1928 AND 1929 Depth of sample Deficiency of soil moisture in feet Station 18A Station 18B Station 18C Station 18D' 0-3 In inches 5.10 4.33 1.51 In inches 5.12 2.64 1.86 In inches 4.90 4.45 1.48 0.35 In inches 4.42 3-6 4 00 6-9 9-12 0.80 0.64 Totals 10.94 9.62 11.18 9.86 Run-off. Measurements of run-off from the mountain catchment areas into the valley and the surface water discharge from the basins have been made for some years by the United States Geological Survey and more intensive studies have been made during the last three years. Very little is known, however, as to the amounts of surface run-off from the valley floors, and plots have, therefore, been selected in typical soil and under other conditions with the view of making careful studies of such amounts. A part of the surface run-off from the valley floors may be termed local as it flows directly into depressions and then percolates into the ground without reaching the main surface streams. This local surface run-off is measured volumetrically by collecting the discharges from small areas in suitable reservoirs. Measurements of the surface run-off from larger areas are made by installing Parshall measuring flumes* with automatic recorders in the drainage channels. During the mnters of 1927-28 and 1928-29 there was no measurable rainfall run-off from undisturbed soil with native cover. Certain cropped areas, however, showed noticeable amounts of run-off. This mn-off occurred in areas cultivated several times during the year, particularly citrus groves. The greatest amount of run-off occurred on the ancient alluvial soils where a plow sole is most readily formed, but there also was some run-off in the groves on recent alluvial fine sandy loam. The gravelly areas around Upland and Claremont did not show any measurable run-off, but water stood in furrows in some groves in these areas and a slight increase in rainfall intensity would have caused run-off. Records were obtained of the amount of run-off from rainfall at four locations during 1928-29, but its ratio to the total seasonal rain was less than three per cent, even on the intensely cultivated groves. All plots on soil with undisturbed cover showed no run-off during either the season of 1927-28 or 1928-29. The average contribution to ground water from local surface run-off of rainfall during the seasons of 1927-28 and 1928-29 therefore was considered to be of very minor importance. * The improved Venturi flume, by R. L. Parshall ; Bulletin 335, Colorado Agricul- tural College. 92 DIVISION or WATER RESOURCES The records for the 1929-30 season indicate an appreciable contribu- tion to the o^roimd water by local surface run-off to low spots in the Riverside district of ancient alluvial soils. The season was one of above normal rainfall for the district and whenever the storms Avere of long duration or of high intensity appreciable run-off occurred. One field of 11.8 acres that had an oat crop growing during the winter showed a total run-off of 3.55 inches, 28 per cent of the rainfall. For the same period, the run-off from an adjacent native brush plot was 0.74 inch, six per cent of the rainfall. Similar comparison by artificial rain tests shows an even more pronounced run-off from cultivated areas. *i^l The penetration of rain by local surface run-off to low lying areas appears to be the principal avenue by which it reached the ground water in the Riverside area of ancient compact alluvial soils. Tables 58 to 61, inclusive, show the run-off records for the Riverside area for 1929-30 and Table 62 gives the intensity of rainfall at Riverside for the 1929-30 season. TABLE 58 RAINFALL RUN-OFF FROM RIVERSIDE FIELD PLOT 1 5.28 Acres of Navel Oranges on Ramona Loam Soil Date of storm causing run-o£F Total rain for storm in inches Total run-off for storm in inches 1930— January 9-12 - - 3.36 .76 .52 0.71 January 14-16 .05 January 26-27' .03 Totals 4.64 0.79 ' No further record, as grove was disked, thereby destroying the drainage ditch. TABLE 59 RAINFALL RUN-OFF FROM RIVERSIDE FIELD PLOT 6> 11.8 Acres of Oats on Ramona Loam Soil Date of storm causing run-off Total rain for storm in inches Total run-off for storm in inches 1930— January 9-12 _ January 14-16. . _ January 26-27. _ 3.36 .76 .52 .66 2.61 .74 1.83 1.29 1.02 Trace .11 .18 March 14-17... March 31 -..\ prill April30-May 2 May 3-5 . 1.29 .32 .17 .46 Totals 11.77 3.55 'Note— Total rain January 5 to May 5, 1930 Total run-off January 5 to M.ay 5, 1930 Per cent of run-off January 5 to May 5, 1930. .12.69 inches . 3.55 inches -.28 per cent i RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 93 TABLE 60 RAINFALL RUN-OFF FROM RIVERSIDE PLOT 7— NATIVE BRUSH" 100 Square Feet in Plot on Ramona Loam Soil Date of storm causing run-off Total rain for storm in inches Total run-off for storm in inches 1930— January 9-12 3.36 2.61 0.56 .18 Totals 5.97 0.74 'Note— Total rain January 5 to May 5, 1930 12.69 inches Total run-off January 5 to May 5, 1930 0.74 inches Per cent of run-off January 5 to May 5, 1930 6 per cent TABLE 61 RAINFALL RUN-OFF FROM RIVERSIDE PLOT 8— CLEAN FURROW PLOT IN WALNUT GROVE 100 Square Feet in Plot on Ramona Loam Soil Storm of March 30, March 31, April 1, 1930 Rain during two periods of high intensity 0.38 inch Total run-off .32 inch Amount absorbed in nineteen minutes 0.06 inch Absorption coefficient 0.19 inch per hour TABLE 62 INTENSITY OF RAINFALL ON RIVERSIDE RUN-OFF PLOTS' Table gives intensities of 0.20 inch per hour or higher Date of storm Start of interval End of interval Minutes in interval Rainfall in inches during interval Intensity of rainfall in inches per hour 1930- January 6 January 9 January 9 January 9 January 11 January 12 January 27 March 4_. March 14.. March 14.. March 30_. March 31.. April 30... April 30... May 3 May 3 May 4 11:34 p.m. 4:55 p.m. 7:00 p.m. 10:05 p.m. 4:55 a.m. 4:40 p.m. 11:28 a.m. 11:05 p.m. 6:50 p.m. 8:50 p.m. 2:48 a.m. 1:33 p.m. 1:18 p.m. 5:02 p.m. 6:45 p.m. 6:55 p.m. 4:25 p.m. 11:39 p.m. 6:00 p.m. 9:00 p.m. 10:38 p.m. 7:25 a.m. 5:28 p.m. 11:40 a.m. 11:18 p.m. 8:50 p.m. 11:20 p.m. 2:58 a.m. 1:52 p.m. 1:35 p.m. 5:32 p.m. 6:55 p.m. 7:20 p.m. 4:40 p.m. 05 65 120 33 150 48 12 13 120 150 10 19 17 30 10 25 15 0.10 .24 .50 .17 .83 .22 .04 .13 .63 .59 .11 .27 .12 .10 .13 .14 .10 1.20 .22 .25 .31 .33 .28 .20 .60 .32 .24 .66 .85 .42 .20 .78 .34 .40 'Total rainfall January 5 to May 5, 1930=12 .69 inches. Evaporation and Transpiration Losses. Evaporation From Bar-e Soil After Rain — Ontario Plot. — During the 1927-28 season, a late spring rain afforded an opportunity to observe the rate of evaporation from the soil surface following" a rain. The plot used for the test had a winter crop of grass that had matured and died before the May rain so the soil was dry before the rain and the out- line of penetration of the May rain could, therefore, be readily observed. The dead grass cover was removed so that the soil surface was bare. 94 DIVISION OF WATER RESOURCES The average depth of penetration was obtained by digging a trench twelve feet long and measuring the outline of the wetted soil. Soil samples were taken at six points along the face of the trench in six- inch increments of depth. On each succeeding date of sampling, the face of the trench was advanced six inches into undisturbed soil. The amount of rain stored in the soil was computed from the soil moisture data and the outline of penetration. Results are graphically shown in Plate XXIV. The total rain May 8 and 9 was 1.49 inches and 0.79 inch of this had evaporated by May 29. This may be considered as representative of late spring or early fall conditions. During the colder months of January and February, the evaporation is much less, as shown by the complete season 's results for 1928-29 in Plate XXV. PLATE XXIV 8 10 12 14 16 EVAPORATION FROM BARE SOIL AFTER RAIN, ONTARIO. Edison Avenue Plot. — Evaporation from the soil after each rain was measured in several ways throughout the season. One of the methods used was to select a plot 60 feet square on which the soil was dry to a considerable depth before the occurrence of rains in the fall. All plant growth was removed and the plot kept bare throughout the rainy season. A thorough sampling was made of the plot while it was still dry to obtain the initial moisture content. After each rain a trench twelve feet long and of required depth was dug and the wetted outline of rainfall penetration was noted. This was done daily for five days after each storm and then at less frequent intervals until the next RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 95 storm. The trench was immediately refilled after the wetted outline was obtained and the face of the next day's trench was advanced six inches into undisturbed soil. Soil samples were taken in six-inch incre- ments of depth at from five to seven points along the face of the trench. In other places soil tubes were used and five or seven holes put down to depths below the plane of rainfall penetration. Here, also, samples Avere taken in six-inch increments of depth. From the data thus PLATE XXV V ^ — > Plot B b>- ■ — —I RAINFALL F »ENET RATION V A v N 12 I 10 DC 1 1 1 1 1 11.94 inches total rainfal 3 A CCUM LA TIVE RAINFALL - ir -'lo .94- AND SOIL STORAGE 1 1 1 1 J 1 1 1 St by To al r ainf ill— \ i J JL. — - r •^ i-ii. _ R ainf i\\ s ore i in' he s 3i|- "\ f ,^ ''-E.vaporation Mo5s / ^ n stor 1 1 1 6.00 inches - i ■ed in the sm\-^ \ , / '— n L / L r TT L r ^Net storage f ^ J i%i cc.s RAINFALL BY STORMS Oct. Nov. Dec. Jan. Feb. March April 1928 1929 EVAPORATION OF RAIN FROM THE SOIL, EDISON AVENUE, ONTARIO, 1928-1929. obtained the amount of rain stored in the soil was computed from day to day, and the difference between stored rain in the soil and total rainfall charged to evaporation. After the rain had penetrated more than four feet into the soil, trenching became unduly laborious. Moreover, the probable error in computing the total stored rainfall in the soil increased as the pene- tration increased. To overcome these difficulties, a tract having an area of 800 square feet was roofed over in the fall before the rains started 96 DIVISION OF WATER RESOURCES and this area was kept dry until the penetration in the soil not so covered was four feet deep. The roof then was removed and a new series of observations started from the ground surface. Data from this second plot were not used until the percolation had extended down- ward more than six inches. Data from the two plots gave an accurate record of the evaporation from the soil under actual field conditions throughout the entire rainy- season. Over 2500 soil samples were taken from the two plots during one season so as to reduce the experimental error as much as possible. The results are given in Plate XXV, which shows the rain by storms, the total rain, the outline of rainfall penetration in the soil, the amount of stored rain in the soil and the evaporation throughout the season. The evaporation after each storm is given in Table 63. TABLE 63 EVAPORATION FROM BARE SOIL AFTER RAIN— EDISON AVENUE PLOT Season of 1928-1929 Date of storm Rainfall in inches Actual evaporation before nex t storm in inches 1928— October 13-14 0.40 1.10 .93 .95 1.05 1.56 .85 .09 .77 1.79 .08 2.37 0.30 .60 .22 December 11-13 .36 1929— .11 .29 .57 March 10-12 March 22 .82 >.67 Totals. - -- 11.94 '3.94 ■ To April 15. Interception of Rain hy Vegetation. — Interception by vegetation may be considered as one factor in the evaporation of rain. Citrus crops retain their foliage throughout the winter and intercept a certain portion of the rain before it reaches the ground. The amount of interception that may be expected was determined experimentally by weighing, sprinkling and reweighing a large lemon tree. The tree obtained for the test was 40 feet in circumference at the drip and twelve feet tall. Plate XXVI shows the tree as it appeared, somewhat wilted, eighteen hours after the start of the test. The test was started on May 22, 1930. The tree was cut off at the base of the trunk at 7.00 p.m. and fitted with a base so that it could be set on a platform scale. At 7.50 p.m., the tree was weighed and then sprinkled for fifteen minutes with a fine spray and then weighed again. The amount of water held on the leaves, branches, and trunk of the tree was found to be equivalent to 0.04 inch depth over the area within the drip of the tree. The test was repeated at midnight and again at 4.00 a.m., and then seven other times until noon of May 23. After 7.00 a. m., each succeeding test was started as soon as the RAINFALL PENETRATION AND CONSUMPTIVE USE OP WATER 97 water from the preceding test had disappeared from the leaves. The tree did not appear wilted at 5.00 a. m., but the leaves drooped quickly after the sun's rays reached the tree and the tree did not regain its normal appearance even after continued sprinkling. The night was clear and calm until midnight, but a light east wind started shortly PLATE XXVI INTERCEPTION OF RAIN AS DETERMINED BY WEIGHING AND SPRINKLING A LEMON TREE. MAY, 1930. after midnight, becoming brisk after 8.00 a.m. After the first test the tree did not again show as great an increase in weight in any of the succeeding tests, due in part to the branches and trunk being slightly wet when the succeeding tests were started. 7—81141 98 DIVISION OF WATER RESOURCES Results of Test No. 1. — Weight of tree and support 50 minutes after cutting tree_462.0 pounds Weight of tree and support immediately after sprinkling_490.0 pounds Weight of tree and support after rapid dripping from leaves had ceased 485.5 pounds Weight of tree and support after shaking tree vigorously-480.5 pounds In view of the above test, interception of rain on tree foliage was not considered of sufficient importance to warrant its consideration as a separate factor in the disposal of rain on the valley floors of this area. Interception and evaporation from the leaf surface is offset by the effect of shading the ground and reduction of evaporation from the shaded soil surface. Summary of Winter Consumptive Use. — The detailed results of winter evaporation-transpiration studies have been given in previous chapters. With the exception of citrus, it has been very difficult to separate these two factors in rainfall disposal. In the Ebert plot A (citrus) the monthly winter transpiration use of water varied from 0.72 to 1.43 inches between November 1, 1928, and April 30, 1929, with an average of 1.05 inches per mouth. The average for the months of February, March and April in 1*930 was 1.08 inches per month. Investigations have shown that bare lands and vineyards and deciduous orchards that are clean cultivated have no material transpiration loss during the winter period. A summary of the average winter evaporation-transpiration rate per 30 days is given in Table 64, both for brush plots and for grass and weed plots. The average consumptive use of water for brush was 2.41 inches per 30 days, while that for grass and weeds was 2.07 inches per 30 days. These values, together with the average fall soil moisture deficiency, may be used in calculating the probable consumptive use for any year from the daily rainfall records. TABLE 64 SUMMARY OF AVERAGE WINTER EVAPORATION-TRANSPIRATION RATE PER 30 DAYS FOR BRUSH AND GRASS AND WEED PLOTS Plot Crop Period Evaporation- transpiration losses in inches per 30 days Brush.. . . . October 25. 1927, to April 26, 1928 October 12, 1928, to May 15, 1929 2.44 Brush 1.94 Brush October 25, 1927, to April 26, 1928 October 12, 1928, to May 15, 1929 2.32 Brush 1.86 January 5, 1930, to June 9, 1930.. 3.07 Station 76 - . Brush.. . . . October 25, 1927, to April 27, 1928 October 12, 1928, to May 15, 1929 Januarys, 1930, to June 3, 1930 2.63 Station 76 Brush 2.19 2.80 2.41 A2 Grass and weeds Grass and weeds Grass and weeds. Grass and weeds Vetch. December 6, 1927, to April 14, 1928 December 6, 1927, to April 17, 1928 December 6, 1927, to April 17, 1928 January 19, 1928, to AprU 11. 1928 December 23, 1927, to April 13, 1928 December 24, 1927. to April 2. 1928 2.37 D2 - - 1.40 E2 2.05 F2 2.41 U2 2.16 H2 2.03 2.07 RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 99 The average maximum annual opportunity for consumptive use of water by brush of the valley floor may be estimated as follows : The average initial fall moisture deficiency for the brush plots was 10.6 inches. The average winter rate of evaporation-transpiration was 2.4 inches per month. The normal distribution of rainfall is such that the full evaporation-transpiration opportunity is not met by the rains that come in October, November and April. This deficiency of rain- fall is indicated to be 3.0 inches. With normal distribution of rain- fall from October 1 to April 30, then, the average maximum annual opportunity for consumptive use is indicated to be 24.4 inches, com- puted as follows: 10.6+(7X2.4)— 3. However, direct deep penetration below the root zone occurs at any time when the total rain to that date has been sufficient to replenish the initial fall deficiency in soil moisture and the evaporation-transpir- ation demands up to that date. When the seasonal distribution of rain is such that the storms are concentrated within a period of four months, deep penetration may be expected after the total rain for the season passes 19.0 inches. Daily rainfall records must be used in determining the annual con- sumptive use of water by brush and the yield to the underground water supply by direct deep penetration below the root zone, as the distribu- tion of the storms is important. When the total seasonal rain is less than nineteen inches, it is usually entirely consumed by evaporation and transpiration on the brush covered areas of the valley floor. Pene- tration of rain to the ground water also may occur at any time when the intensity is high enough to cause local surface run-off to low spots. This factor, however, has been considered separately under the title "Run-off." Soil Drainage With No Surface Evaporation or Transpiration. Records from the 20-foot level in the Devil Canyon tunnel showed continued slow losses of soil moisture over periods of months. There were no roots present at any of the points of sampling and the losses could not be charged to air circulation in the tunnel as borings for samples were made through undisturbed soil to distances of five feet laterally from the sides of the tunnel. Edison Avenue Plot. — To check the rate and amount of soil moisture drainage that might occur in the soil below the root zone, soil drainage plots were established at Edison avenue, five miles south of Ontario. Starting in September, 1928, a plot 60 feet square has been kept entirely free of vegetation. From October 12, 1928, to April 6, 1929, 11.94 inches of rain fell on the plot. On June 18, 1929, a six-inch irrigation was applied to a 20-foot square area in the center of the clean cultivated plot. The center 144 square feet of the irrigated area was boarded over and sealed with roofing paper, and the entire 400 square feet covered with a corrugated iron roof. Plot A is shown in Plate XXVII. The movement of soil moisture under the sealed area, then, is entirely without the influence of transpiration or direct surface evaporation. The moisture from the six-inch irrigation moved rapidly downward during the first few days after the water was applied. There also has been a continued slow movement of moisture, out of the top six feet of soil, extending o"«^er a period of fourteen months. 100 DIVISION OF WATER RESOURCES • To make certain that this movement of soil moisture was downward, a second plot was established in January, 1930. This plot was set in a barley field that had a summer weed crop after the spring harvest of 1929. The soil was dry when the rains started in January, 1930. From January 6 to 12, 3.72 inches of rain fell on the plot and it then was covered and sealed in a manner similar to that employed in protect- ing the first plot. Soil sampling under the sealed area is accomplished by boring through the roof with a wood auger and then using standard soil tubes to obtain soil samples. Each hole is backfilled and then resealed with tar and roofing paper. PLATE XXVII EDISON AVENUE SOIL DRAINAGE PLOT. AUGUST, 1929. The soil moisture record from the two plots is given in Tables 65 and 66. All samples are being saved and moisture equivalent determina- tions will be made after the test is completed. Evaporation From Water Surface. Records of the evaporation from a free water surface are available at Ontario, San Bernardino, Riverside and Santa Ana. The type of pan at each location is the standard United States Weather Bureau Class A pan. The Riverside record is kept by the Citrus Experiment Station of the University of California and covers a period from November, 1924, to date. The total annual evaporation at this station shows a range from a minimum of 64.33 inches recorded in 1927 to a maximum of 70.06 inches recorded in 1925. RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 101 ? o .13 i -a "o 1 > -5- 1 .2 s £ 3 '3 p f- 1 CO t>. M U5 «0 c<5 O m lO t^ to OJ O O t^ C^ -"l" xf o tooto 1 3l CO*" to 1 « O -H lO O to •» t~ U5 05 CO C^ O •* m M M !M 50 t>. 'oooooot^ tor^ to x)oo t^oot^t^OiO Oi Oioooo t^eoo (Stow :0 OO i(MtOOmcO<»0<»< 1 to 05 00 to •«. 0 ffO ■* (M ■* M CO OS — 1 00 lO t^OOTf odrt'co CNCOCO -^j* 1 ^ 00 air^ O) 00 lO i^ 05 00 u3 1-" t^ OS to 00 o o •-H 3| ^H . cnr^ t^ tooooo^ o ^ t^^H lo TJ1CO oi^H ic^ to CON CO to icC-^-'J^'^MOO-^ifSiOtOCOtCtDCOkCQOOt^t-- 3| C3 V tO 'cOXS Osas«MOC^OC<50C. 00 t^ 00 t~ 00 00 00 00 Ol Ol 03 -H -OSC0CDt^U5l0^ t^OCO COCO-* C^C^(M ^ 1 ^ CM CM CM CM CM CM CM Cq Cq CM CM CM (M C^ CM CM CM CM 05 ^ OS 1 lO Oi lO t^ t^ CD CO -H CO CM CO 05 00 -^ Oi TJ* 00 OO '^J* iricoh- CO . -rji Tf lO CM M" lO ^ '^ CO -^ Tt^ CO "* CO -<»* -^ lO CO CO CM « (M CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM 00^ r^ ' t^ OSCOOOCOliJ^H OICOOO W »O00»OCM OOO OCM iftOiOi O <0SC0»-<0it^01000S^»-i^^CTt« OOOTJi t^ b- t^ t- ilr^^COCOCMCMCM^^^O^OOOOOOOOt^t^ -* . O CO CM CO OS OO liti CO '-^ CO O 05 CO »0 »0 U5 CM O I^ ::« CO t ^H ^ ^ O C35 OS OS OS 0500 00 t— t^^-cDCO CO CD »0 5 ^ ^1 '-* SocDlOCM-'J't^CO^OI^'^'^OCM-^'^^^OO tnunui CO rtCMOOi050000C00000l>-t^t~-t^l>>cDC0c0C0iO 5 ^ 3 w 5.6 re -inches 11.8 9,9 8.8 8.5 8.1 8.0 7.6 7.9 7.6 7.3 7.0 7.0 6.9 6.9 6.2 6.2 5.9 5.8 5.7 CO-* — 11 o 1^ 4.2 d — six ao 10.8 8.6 8.5 8.0 7.5 7.4 7.0 7.6 7.4 7.5 6.3 6.2 7.0 6.6 6.0 5.9 5.6 5.5 5.2 o ■28 '=? o 3 u 2.2 Irrigate 12.5 10.2 8.3 8.5 7.9 8.0 7.8 7.9 7.3 6.5 5.5 5.6 5.5 ■7.4 6.5 6.6 6.3 6.4 5.8 CO CO lO 1 Q 1929— June 17 June 18 June 19 June 20 June 21 June 22 June 23 June 24 June 25 June 26 June 28 July 1 July 5 July 8 July 12 July 18 August 17... August 28..- September27 October 26.. December 2.. 1930— January 7 May 3 August 27... 102 DIVISION OF WATER RESOURCES So W O o Z a, re "o ^g lO 1 KM'* 1 CO 1 1 a>oo tr>£ 5" 00 ira k. Itk I '•>»;o> oo -g S.P 1 1-^ 1 loo P^ 5§ 00 oo lO 1 !•*« 5 ■" 1 CO t >00 03 kOiS C3 u t^ lO ^ ' ■* ' i '~: °^. •^■s S| ':-V 1 IcOl^ o « O u t^ t^ k* lo '• 1 -Hio o .^ a> -*3 D-g i^ 1 IcOt- >Oi„ C3 u to lO li IcO 1 Im t- £ £" .J3 "5 .a U5 J_, 1 -^-^CO t^^ •re's p,"S lt-^g^oio>o O QJ o a u a> W5 •"• lO ^ 1 o> loooco 1 o »^ a| 1 CO lOO a>c33 ira^ c] O '3 .13 ^ •<>< "S lOOOS^ oco 1 ■* « C-^ t-l CO O V -7 V O O u a -S a ■<*< *"* -* !-• CC*^ i(MCM "5 5^ COM IcOCOlO o "5.2 a OOM CO-*** oo s m"S S.a 04 CD CO CO CO U5 °>2 5" CO CO !-• O, 1 1 1 1 1 2*^ S,g (m' 1 1 ! t ! i«^ a o i i i i i c^ lO oa^H OiiO^ CO o.2 a u '^ 1 1 1 1 1 '"' ira cDlO'*rtOOCO 0,2 ^1 C3 op f^ as iO ip '"' O -t^ k> O li«tOo ** o aa OOO t^cO CO U5 o^ .»o a u °d : I ; i ; : "o J: H) C ■ ■i £ nam 1 '. ^ qS ** ST a* O.J3 _■=■- p-a jvT « o 2 o > "t! T3 fl C ra b C3 CO,„ rt C3 0) =* « >.o a, o S S «> a o o5*.i:co c-S B a g g o "^cSIIIII P^ -e -e -e -s -s -e O CL, PL, PL, p^ Ch PL, RAINFALL PENETRATION AND CONSUMPTIVE USE OF WATER 103 The stations at Ontario, San Bernardino and Santa Ana were established during the progress of this investigation. The variation between stations is small, as indicated by the records for the year July 1, 1929, to June 30, 1930, as follows : f^fation Ontario San Bernardino Riverside Santa Ana P(Tlod July 1, 1929, to June 30, 1930 July 1, 1929, to June 30, 1930 July 1, 1929, to June 30, 1930 July 1, 1929, to June 30, 1930 Evaporation in inches 66.42 67.95 66.90 67.62 The maximum deviation from the mean reading at these four stations is 1.2 per cent. Table 67 gives the records from Ontario, San Ber- nardino and Santa Ana by months. The monthly record for the Riverside station is given in Table 68. Table 69 gives the weekly record for the Ontario station. TABLE 67 EVAPORATION FROM WATER SURFACE—CLASS A WEATHER BUREAU TYPE OF PAN AT ONTARIO, SAN BERNARDINO AND SANTA ANA Month Ontario' San Bernardino' Santa Ana' 1928 1929 1930 1929 1930 1929 1930 January . ._ In inches In inches 1.87 1.85 3.53 3.83 7.31 8.59 10.17 10.55 6.39 6.21 4.96 3.32 In inches 1.51 2.57 3.54 5.19 5.25 6.76 8.43 7.65 In inches In inches 2.32 3.46 5.02 5.38 5.89 7.22 8.33 In inches In inches 2.28 February 2 87 March _ 3.39 6.28 6.04 7.37 9.74 9.28 8.25 4.44 3.46 1.96 4 48 April- - _ . . .. 6.05 7.78 8.89 9.78 8.81 5.69 5.58 4.98 3.82 8,39 8.23 8.89 8.90 5.65 6.06 5.26 3.44 6 79 June ^ July August . . ... 6.95 8.54 September October November _ December . _ Total evaporation, July 1, 1929, to June 30, 1930— Ontario 66.42 inches San Bernardino 67.95 inches Santa Ana 67.62 inches 'Observations by C. A. Taylor. ■ Observations by A. A. Young. TABLE 68 EVAPORATION FROM WATER SURFACE— CLASS A WEATHER BUREAU TYPE OF PAN AT CITRUS EXPERIMENT STATION, UNIVERSITY OF CALIFORNIA, RIVERSIDE' Month 1924 1925 1926 1927 1928 1929 1930 January. In inches In inches 3.558 2.626 4.990 5.282 6.523 8.402 10.558 9.618 7.152 3.470 5.041 2.937 In inches 4.422 3.808 4.851 4.570 7.856 7.437 9.045 9.317 7.003 5.899 2.561 1.888 In inches 1.199 .935 4.127 3.999 7.610 7.596 9.975 10.302 7.227 5.620 3.768 1.975 In inches 2.538 4 503 3 903 6.731 5.763 7,590 9.523 9.441 7.739 4.705 3.215 2.827 In inches 2 406 2.384 4.122 4.593 6.905 8.611 10.093 9.970 5.405 5 526 5.492 3.598 In inches 1 755 February 2 206 March 3 891 April .. ... 5 437 May .. . 5 845 June ... 7.684 July 9 504 August ._ September .. October November 4.400 3.362 December. Totals 70.057 68.657 64.333 68.478 69.105 ' Records furnished by Dr. L. D. Batchelor, Director, Citrus Experiment Station, University of California, Riverside. 104 DIVISION OF WATER RESOURCES TABLE 69 WEEKLY RECORD OF EVAPORATION FROM WATER SURFACE-CLASS A WEATHER BUREAU TYPE OF PAN AT ONTARIO 1928 1929 Week ending Loss for week in inches Week ending Loss for week in inches Week ending L(K8 for week in inches February 13.. February 20.. February 27.. March 5 March 12 March 19 March 26 April 2 April 9 April 16 April 23 Apial30 May 7 May 14 May 21 May 28 June 4 June 11 June 18 ^- June 25 July 2 July 9 July 16 - July 23 July 30 August 6 August 13 August 20 August 27 September 3. September 10. September 17. September 24. October 1 October 8 October 15 October 22... October 29... November 5. November 12. November 19. November 26. December 3 . December 10. December 17. December 24.. December 31.. 0.97 .81 .86 .62 .67 .93 .69 1.12 1.29 1.46 1.54 1.63 1.99 1.00 1.04 1.39 1.44 1.55 1.88 1.64 2.08 2.00 2.36 2.34 2.19 1.77 2.22 2.08 2.20 2.20 2.26 1.76 2.00 1.50 1.29 .87 1.18 .75 .64 .90 .58 1.10 .58 .54 .28 .47 .47 January 7_. January 14.. January 21.. January 28. . February 4 . February 11. February 18. February 25. March 4 March 11 March 18... March 25.... April 1 April 8 April 15 April 22 April 29 May 6 May 13 May 20 May 27 June 3 June 10 June 17 June 24 July 1 July 8 July 15 _ July 22 July 29 August 5 August 12... August 19 August 26 September 2 September 9 September 16 September 23 September 30 October 7.. October 14.. October 21... October 28. _ November 4 November 11 Novcmoer 18 November 25 December 2. December 9. Dccembcr 16. December 23- Decembcr 30. 54 .67 .18 .31 .29 .33 .47 .71 .71 .66 1.08 .81 .93 .70 1.00 1.79 1.84 1.65 1.02 2.11 1.61 1.71 2.56 2.15 2.23 2.18 2.58 2.37 2.15 2.49 2.36 2.35 2.28 1.35 1.04 1.33 1.17 1.61 1.15 .94 2.00 1 26 1.01 1.30 1.23 .81 .71 .52 .89 .98 January 6.. January 13.. January 20.. January 27. . February 3. February 10. February 17. February 24. March 3 March 10... March 17 March 24 March 31.... April 7 April 14 April 21 April 28 May 5 May 12 May 19 May 26 June 2 June 9 June 16 June 23 June 30 0.64 .17 .22 .36 .55 .70 .71 .51 .59 .53 .66 .74 1.32 1.04 .93 1.60 1.46 .36 1.08 l.U 1.88 1.43 1.75 1.32 1.42 1.82 PART II EVAPORATION AND TRANSPIRATION LOSSES FROM MOIST AREAS I CHAPTER I GENERAL STATEMENT* Introduction. This progress report presents the results obtained in the first year's study of some of the ground water problems in the Santa Ana River Valley in southern California. Soil moisture studies carried on simul- taneously by the Division of Agricultural Engineering in various parts of the Santa Ana River Basin were presented in Part I. The original purposes of this study were to determine, by tank experiments, the evaporation from bare uncultivated fine sandy loam soils and the consumptive use of water by salt grass (Distichlis Spicata) and Bermuda grass (Cynodon Dact^don), where the water table is six feet or less beneath the ground surface. With these objects in view, equipment for two experiment stations was installed early in 1929. Because of differences in climatic conditions it was deemed advisable to divide the work at the outset between San Bernardino County, in the upper, and Orange County, in the lower Santa Ana basins, with the intention of installing the greater part of the equipment at the latter place. The original plan has been extended from time to time and additional tank experiments now are being conducted to determine the consump- tive use of water by tules, cat-tails, rushes and willows, but data obtained from only one tank of tules is now available, the other tanks having been installed too late to permit of the incorporation of the results obtained in this report. Investigations to determine the effect of oil films in preventing evaporation from water surfaces with a view to finding a means of preventing large evaporation losses from storage reservoirs, and studies of the surface, or perched water table of the Coastal Plain of Orange County by measurement of surface test wells throughout one dry and one wet season were carried on. Records were obtained of the rise of the perched water table due to rainfall, and the amount of precipitation which penetrated to the perched water table, increasing the underground drainage flow from a portion of the New- hope Drainage District, was measured. Summary. 1. Data regarding evaporation from bare soils and transpiration from salt grass and Bermuda grass grown in tanks in which the water levels have been held at predetermined depths have been collected at experi- ment stations at Santa Ana and San Bernardino. From the data thus obtained the following conclusions have been reached : * Part II was prepared by Harry F. Blaney, Irrigation Engineer, and A. A. Young, Assistant Irrigation Engineer, under the general supervision of W. W. McLaughlin, Associate Chief of Division of Agricultural Engineering, U. S. Department of Agri- culture. (107) ]08 DIVISION OF WATER RESOURCES No evaporation occurred from bare surfaces of undisturbed fine sandy loam soil in tanks having a water level four feet below the soil surface. The monthly evaporation from the same tanks, but with the water Itvel three feet below the surface, for the period from January 1 to April 30, 1930, inclusive, was less than 0.1 inch. For similar tanks having a two-foot water level, evaporation from bare soil averaged 0.75 inch per month during five summer months and 0.25 inch per montli during four winter months. In tanks containing disturbed soil Avith a two-foot depth to the water table, soil evaporation ranged from 2.95 inches during August, 1929, to 0.73 inch in February, 1930, with a total of 14.58 inches from August, 1929, to April, 1930, inclusive. This is 3.5 times the evaporation recorded for the tanks containing undis- turbed soil with the water table held at the two-foot depth for the same period. Consumptive use of water by salt grass growing at the Santa Ana station in tanks having a two-foot water level varied from 5.64 inches in July, 1929, to a minimum of 0.72 inch in January, 1930, with a total of 35.3 inches for the twelve-month period, May, 1929, to April, 1930, inclusive. With a four-foot water level, a maximum loss of 2.96 inches occurred during August, 1929, a minimum loss of 0.31 inch during January, 1930, and a total use of 13.37 inches for the entire period. At San Bernardino, Bermuda grass growing in tanks having a three- foot water level used a maximum of 5.49 inches during July, 1929, and a minimum of 0.66 inch in February, 1930, with a total of 32.53 inches for the twelve-month period ending April 30, 1930. In tanks having a two-foot Avater level, the maximum use of 6.51 inches occurred during July, 1929, and the minimum use of 0.45 inch during January, 1930, with a total use of 37.27 inches for the period. 2. Tules growing in submerged soil in a tank not under natural swamp conditions used a maximum of 28.38 inches of water in October, 1929, and a minimum of 1.86 inches in January, 1930, when the tops were dead. The total consumptive use from August, 1929, to April, 1930, inclusive, was 139.32 inches, and for the twelve-month period from August 1, 1929, to July 31, 1930, inclusive, was 213.56 inches. 3. Commercial hot water tanks were successfully used as Mariotte reservoir tanks for automatically supplying water to soil tanks at pre- determined constant levels in determining losses by evaporation and transpiration. Great care is necessary to protect the tank against temperature changes. The Mariotte tank and connecting pipe system must be air tight since the smallest air leak into the system upsets the equilibrium of forces responsible for successful automatic operation. The Mariotte tanks at Santa Ana are buried in the ground and are less affected by temperature changes than those at San Bernardino, which are above ground but boxed in and protected by asbestos paper and shavings. An increase of three degrees in temperature at San Bernar- dino increased the value of the vapor pressure in the partial vacuum chamber of the tank enough to reduce the water level in the glass gauge one millimeter. 4. During wet weather, soil tanks were protected from rains in order that the soil moisture content within the tanks might remain unchanged. If rainfall is not allowed on tank surfaces and water consumed by evaporation or transpiration is supplied only by a water level held at a EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 109 constant level, the experiment is a laboratory one, and the data obtained are not entirely applicable to natural field conditions. On the other hand, if rainfall is allowed upon the tank surface, soil moisture condi- tions within the tank will be changed until evaporation or transpiration removes the excess moisture and the initial conditions of the experiment, which were to maintain a constant water level at a predetermined depth, will no longer exist. Each method seems open to objection, but during the past season that of covering all soil tanks was adopted as probably constituting the better plan. 5. Various tests were made with the view of preventing evaporation from water surfaces by the use of oil films. Several grades of cylinder oil were used without material success. A portion of the oil film dis- appeared from the tank surface either by evaporation of the more volatile oil substances or through absorption by the water upon which it floated. Effective prevention of evaporation lasted but a few days and at the end of six weeks all benefit due to the oil film had dis- appeared. ^ 6. The ground water underlying much of the agricultural area of Orange County is divided by an impervious stratum into a perched water table a few feet below the ground surface and a deeper under- ground supply which formerly was of an artesian character. The perched water table is replenished each year by rainfall, surface irri- gation and occasional floods. It is depleted by soil evaporation, transpiration and drainage run-ofl^. Surface test wells show that the water table does not fluctuate greatly. The deep underground basin, which is the greatest source of irrigation supply, has been depleted during the past 20 years until only a small artesian area remains. Water levels in wells are dropping from year to year, and costs of pumping are increasing with increased lifts. The underground basin is replenished by deep penetration from stream channels and rainfall, underflow from surrounding hills, excess irrigation in areas where a perched water table does not exist and by overflow from occasional floods. 7. Penetration of rainfall through from six to eight feet of fine sandy loam, measured as increased drainage flow between January 1 and June 1, 1930, amounted to less than one-half an acre-inch per acre over an area of 1900 acres with a total rainfall for the season of 11.1 inches. Increases in flow resulted from rains of 0.5 inch or over, and decreases occurred between heavy rains and following light rains. No doubt a part of the rainfall unaccounted for eventually reached the water table by slow drainage. Measurements of drainage flow were discontinued at the beginning of the irrigation season. 110 DIVISION OF WATER RESOURCES CHAPTER II EXPERIMENTS AT SANTA ANA AND SAN BERNARDINO STATIONS Meteorological Conditions. Orange County is about equally divided between the Coastal Plain, upon wliich intensive agriculture is practiced, and the mountainous area lying east and north and covered with chaparral and other forest growths. The Santa Ana River cuts through these mountains in a canyon twelve miles long, dividing the Santa Ana Valley into two parts, with Riverside and San Bernardino counties in the upper and Orange County in the lower basin. Table 1 shows the monthly mean maximum, mean minimum and mean temperatures, the rainfall, and the total number of miles of wind per month at the San Bernardino and Santa Ana stations. The prevailing wind throughout the entire basin is from the ocean. The cooled night air of the Mohave Desert, after being warmed by the sun, flows upward during the day and is replaced by cooler air blowing in from the coast. At times, however, the direction of the wind is reversed and blows from the desert down through Cajon Pass, in the San Bernardino Mountains, across the Wineville district and through the Santa Ana Canyon into Orange County. These northerly winds, locally termed "Santa Ana winds," while they are sometimes cold, are very often hot and dry. When hot Avinds occur, large increases in the use of water by plants are recorded at the Santa Ana Station. The San Bernardino Station is not in the direct line of the Santa Ana winds and hence is not greatly affected. One important modifying factor upon the climate of Orange County is the light fog frequently prevalent for several miles back from the coast. Many of these fogs occur only in the early morning, disappearing shortly after sunrise, but they also are sometimes continuous throughout a period of several daj's. The moister air of the foggy days reduces both evaporation and transpiration. The precipitation which occurs during the cooler months is insuffi- cient for intensively cultivated crops which must, therefore, depend upon irrigation to supply the deficiency. On the Coastal Plain the rainfall increases slightly toward the adjoining mountains, but the increase is small, except in the higher ranges. It is slightly larger at San Bernardino than at Santa Ana. Tables 2 and 3 show the daily rainfall at the Santa Ana and San Bernardino stations, with the total precipitation for each storm throughout the season. The relation between the amount of daily evaporation from the Weather Bureau pan (Tank No. 20) and ground Tank No. 16, at EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 111 Santa Ana, together with the daily maximum and minimum tempera- tures and the daily wind movement is shown on Plate I. In general, evaporation responds to both temperature and wind movement as is shown by corresponding peaks and valleys on the plate, but there are some exceptions. For example, the peak of the wind diagram on March 14, 1930, shows a total wind movement of 200 miles, whereas the usual movement is but 40 or 50 miles per 24 hours. The evapora- tion on the same day from both pan and tank shows a decrease. This decrease was caused by a heavy rain accompanying the high wind in consequence of which the air was so saturated with moisture that very little evaporation was possible. TABLE 1 MONTHLY TEMPERATURES, RAINFALL AND MILES OF WIND MOVEMENT PER MONTH AT SANTA ANA AND SAN BERNARDINO STATIONS Temperature Rain- fall in inches Wind move- ment at Weather Bureau evapora- tion pan in miles per month (A) 3 Wind move- ment at soil tanks in miles per month (B)* Month Mean maxi- mum, in degrees Fahren- heit Mean mini- mum, in degrees Fahren- heit Mean, in degrees Fahren- heit Maxi- mum, in degrees Fahren- heit Mini- mum, in degrees Fahren- heit Ratio ofBto A in per cent Santa Ana Station 1 gag- May" -— 74 76 81 85 79 80 77 72 62 66 68 72 70 51 53 60 60 58 52 41 41 40 44 46 47 48 63 65 71 73 69 66 59 57 51 55 57 60 59 91 95 89 96 gs 101 91 86 76 87 8g 88 83 41 43 52 51 42 36 33 30 30 33 33 39 40 0.03 .11 July .35 1695 1745 1806 1547 1743 1682 2212 1970 2228 1452 1416 1431 1093 1201 1180 1582 1327 1301 85.7 October - - - 81.1 79.2 70.7 1930— 5.55 .55 2.99 .80 1.23 68.9 70.2 71.5 67.4 58.4 Total 11.61 San Bernardino Station 1929— 82 88 95 98 88 85 80 75 61 74 70 77 74 47 50 57 60 55 46 34 33 36 38 41 45 44 65 69 76 79 72 66 57 54 4g 56 56 61 59 94 108 106 106 107 98 91 85 76 87 88 95 95 37 39 49 51 41 31 26 25 24 31 28 35 34 0.12 July .53 1012 1183 1589 1255 1434 1357 1864 1143 967 October .. . - .. 1930— 4.71 1.06 3.99 1.33 1.76 March April May. _. Total 13.50 ' Beginning May 5, 1929. 2 Beginning May 9, 1929. ' Anemometer twelve inches above evaporation pan. * Anemometer twelve inches above soil tanks. 112 DIVISION OF WATER RESOURCES TABLE 2 DAILY RAINFALL AT SANTA ANA STATION WITH TOTALS FOR STORMS, 1929-30 Date 1929— May 24 -.- June 16 June 17 September 4 September 16 September 18 1930— January 5 January 6 January 9 January 10.-. January U January 12 January 13 January 14 January 15 January 17.. _ January 19 January 26 January 27. _. February 20 Rainfall in inches Day 0.03 .05 .06 .01 .01 .33 0.59 .21 1.57 .93 .10 .28 .14 .96 .20 .08 .01 .34 .14 .05 Storm 0.03 Date February 22. February 26. February 27. March 3-.. March 4 March 5 March 13-_. March 14 March 15. _. March 16 March 18.. . March 29... April 29 April 30 1930— May Mav 2- May 3. Mav 4. Mav 8. May 16. Total- Rainfall in inches Day Storm 40 09 .01 .06 .34 .01 .07 1.72 .62 .07 .03 .07 .28 .52 .05 .06 .40 .68 .02 .02 45 .10 .41 2.51 .07 1.99 .02 .02 11.61 TABLE 3 DAILY RAINFALL AT SAN BERNARDINO STATION WITH TOTALS FOR STORMS, 1929-30 Date Rainfall in inches Date Rainfall b inches Day Storm Day Storm 1929— 0.12 .48 .02 .03 0.18 .19 .04 .97 .94 .21 .45 .02 .88 .21 .14 .44 .04 .22 .54 .20 0.12 1930- 0.10 .46 .02 1.90 .25 .24 .45 .67 .01 .01 01 .47 .83 .27 .07 .64 .56 .11 .01 .10 1.06 September 18 .50 .03 .48 September 29 March 14 1930— March 16 2.39 March 30 March 31 1.12 April 13 . April 14. .02 .\pril28 April 29 April 30 .-- May 1 May 2 May 3 4.23 May 4 . 2.85 May 8 .11 .48 May 17 May 18 .11 Total. February 23 13 50 EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 113 w H ' ' ' ^ ' * » ' ' ^ 1 1 1 1 '*? 1 1 1 1 < s > ^ '^ P^ : c r > <; -^ 1 ~ 1- < e - -2 < c gi* a: !5 . — -* > ^ - - — J - ji, a. ^ ■ 5 / ^ ^ ~ ^^^ r ::fc -— - >>- - 2]2* t- 7 - (0 - 4 *^^ ?" " — >, <=i 3 1- _ c^ 3 > s -Q - ^ S X ( -^ b - l^ *^ 2 S / <<__ =- - <( ^ i^ ;> ^/ ^ (T3 - z? 1 s ^•^ s> ^ _ < <^ r* ^^ ' (0 - y^ ^ ^ "> "^^ \ -> l- -~^ —J — 7 < <: ' ^ _> s J 1) ■ "= ---, ■^ / — ■ — ?• E J s ^ / a) - 7 1 \ \ ^ - ^ \ > ' Q ^ <^ <^ s , _^ ^ <. <^ - Z i. 0- >- > UJ ^ > ^ < Or! / ^ i ) f- r , — * 3 UJ a: X 7 J3 rsi'-' <; ">S ^ s a. cc c- < ► 05 < \ > , } - -2| 2 < < > o< i 5- < ^ i M z - 2- - >- 4 >i < ' '< > G ^ Q ^ - "to f ->$ a.ia c UJLi ^ jtuJ t ^ t > } } ^ ' /^ to . U- 1 - s \ 5 P _l 3 u. c 1- f I ^ - -3 - i ^ < ;> - 4) - ^ /-- ^ ■ C / '' r ~ 3 - s <. - -> - ? f - ^ - K }> i > ^/■^ - " > <^ «=: ^ - 2 > ■*u-~.-.— LL y 1 1 1 ' 1 1 1 1 1 1 I 1 1 1 '"'7'Y-T-i-- ^Trr^v. .^ -7^- J May June July August Sept. Oct. Nov. Dec. Jan. 1929 Feb. March April 1930 MEAN WEEKLY AND MONTHLY USE OF WATER BY TANKS 1 TO 4, INCLUSIVE, SAN BERNARDINO STATION, 1929-1930. | { Tank Nos. 1 and 2 at this station maintain a soil water level three |i feet below the surface and Tank Nos. 3 and 4 have a two-foot water jj level. Tank No. 2 has given some trouble in operation and so many of | the records relating thereto are so unreliable that much of the season's' work has been omitted from the final results. ,ES, MAY, 1929, TO MAY, 1930, IN TANKS AT SANTA ANA 12 Mean 13 14 15 Mean 16 19 20 0.180 .277 .127 .096 .097 .179 .234 .519 .482 .366 .587 .636 .823 .944 .870 0.095 .117 .060 .042 .057 .088 .138 .311 .344 .315 .482 .621 .790 .742 .716 2.064 1.716 1.488 1.518 2.016 1.896 1.622 1.932 1.728 1.836 1.872 1.920 1.896 1.728 1.692 2.160 1.740 1.554 2.124 1.776 1.694 2.256 1.752 1.920 2.196 2.124 1.932 3.827 4.107 1.968 0.254 0.449 0.353 0.352 1.812 .373 .620 .848 .866 1.465 1.060 2.100 5.400 2.160 .561 .518 .542 .824 1.197 .854 1.920 5.850 1.944 .689 .657 .392 .738 1.336 .822 1.942 7.324 2.026 .625 .512 .488 .514 .749 .584 1.332 4.951 1.188 .276 .419 .552 .450 .685 .562 1.396 6.190 1.408 .270 .295 .318 .524 .546 .463 1.08C 4.838 1.116 .515 .352 .531 .479 .748 .586 1.344 6.188 1.380 .737 .574 .572 .372 .696 .547 1.416 7.284 1.620 .646 .431 .499 .502 .588 .530 1.020 4.894 1.092 .487 .326 .490 .385 .546 .474 1.092 5.738 1.092 .343 .188 .403 .438 .641 .494 1.524 7.651 1.632 .123 .278 .511 .417 .600 .509 1.344 7.427 1.500 .021 .186 .435 .385 .492 .437 1.416 6.526 1.464 .000 .139 .403 .309 .491 .401 1.032 4.952 1.236 .000 .139 .371 .310 .395 .359 1.080 4.388 1.008 .036 .148 .295 .245 .197 .246 .600 2.700 .636 .070 .131 .159 .266 .324 .250 .504 2.247 .540 .022 .109 .128 .246 .175 .183 .492 1.911 .492 .222 .172 .211 .192 .386 .263 .948 3.261 1.004 .117 .136 .286 .267 .363 .305 .912 3.037 1.188 .095 .169 .272 .287 .277 .279 .636 .636 .612 .063 .063 .137 .234 .085 .152 .252 .252 .408 .010 .021 .063 .140 097 .100 .300 .300 .456 .011 .039 .137 .288 .160 .195 .336 .336 .480 .010 .067 .042 .235 .160 .146 .720 .871 .852 .000 .046 .106 .277 .181 .188 .336 .588 .492 .032 .095 .126 .211 .256 .198 .708 1.152 .876 .010 .081 .148 .171 .255 .191 .552 .730 .552 .021 .105 .169 .265 .203 .212 .708 1.035 .820 .000 .081 .181 .203 .331 .238 .744 ■ .984 .924 .000 .046 .203 .448 .159 .270 .684 .948 .840 .074 .091 .192 .320 .201 .238 .936 1.848 1.272 .064 .209 .234 .288 .385 .302 .876 2.028 1.140 .115 .172 .256 .320 .330 .302 1.020 3.194 1.356 .159 .251 .290 .394 .417 .367 1.128 3.648 1.332 .190 .297 .278 .331 .341 .317 1.212 5.064 1.608 .212 .240 .299 .351 .471 .374 1.368 5.412 1.584 124 DIVISION OF WATER RESOURCES San Bernardino Station. — At the San Bernardino station, located at the Antil plant of the San Bernardino "Water Department, four tanks operated in pairs are filled with undisturbed Chino silt loam and all contain the original Bermuda grass cover. The soil tanks are con- nected to Mariotte supply tanks. PLATE V j V-fcJ oatcr'le wF-] — {3-fe(it irattr I wel l ' UNDISTURBED FINE SANDY LOAM T Mean N^Mean wwkly ioe_ HUM OF TAW 1 May June July August Sept. Oct. Nov. Dec. Jan. Feb. March April 1929 1930 MEAN WEEKLY AND MONTHLY USE OF WATER BY TANKS 1 TO INCLUSIVE, SANTA ANA STATION, 1929-1930. 15, PLATE VI d o E fe Q. OCOO ■a< -*OOQO CO to t^m ^^ t^co CT>— . to in ocoS E- -Hrt CJ C3i0 ^j| t^ t^ t^ t^ 2:2s troofi CO g 2§f^ m 00000 to 05-^ Oiino < oo (NrqcO (M " ^ -._- - -*t^to J3 00 O CO 00-. J* o 2gS m C- co O-^ S oo -.rtrt " — -• — coto-* 5>. 000-9< -s< tot^ 05 00 00 to — -^ -^ to coo CO -*0!tO M-OOOti H tOOCM ^Soo oo cqcoiM 3 — .O— 1 o IM 0-5 oo — — — C-) o CO aso 05 to otor^ tOl^iO <* CO ■^ ^ t^ — cf^CO asora 00-* §^5 o rtrtrt ^ — -H ^ CO — CO ^1 > oooco ■-QO(M i <35tOOO 10 CM 0-* toiom t>- 1^ to CO CO CO CO -H — rt '^ (Nt>)CO oiffl>n >o CO(MCO oot~ c^ So5t- t- 0^0 coto — CO to SiS ■^ to iCM 05 .05 I0i0>0 lO Ctl — Ctl > 000 to 2^0 «o CO 10 E2 is to ^5: is *0 'CO S CMOJ « -^ rtCMCO 3 s •»OCO s t~00O> 0—1 CM i co-in s 22g o .S '=0 .S -■o'S a" ., 03 C fc CD ^ 03 O C — ■^ - '"' M S t,00 c c S ■2 >i'r'^^ c3 *> t- i^^ 128 DIVISION OK WATER RESOURCES to May, 1930, to be 2.01 inches, or 6.7 per cent of the amount evapo- rating from the standard pan. It lias been pointed out when a water table in the soil is raised to a higher level, soil moisture adjustments occur and the record obtained from the Mariotte tank immediately after the change is greater than the actual evaporation. This appears to be the case with these three tanks, as the record shows that the mean amount drawn from the three Mariotte tanks in October was one-half of the amount used in the entire seven months. If only one-third or one-half of the October records, as given, be allowed, the final result will be more nearly correct. The same general result is noticeable in the records for the second tank set, which includes Tank Nos. 4, 5 and (3. The records for both May and June give larger amounts than those of any of the following months, and absorption by the soil during this period is the only method of accounting for this condition. It appears that, because of soil moisture changes occurring in the soil tank, permanent records should not be taken until a period of six or eight weeks has elapsed after the water table is established. If at any time the water level is changed to a higher or lower level this delay would cause a break in the record. If the water level is lowered, a similar soil moisture change would occur, but it is possible the readjustment period might be shortened somewhat, as the movement of water would be aided by gravity instead of working against it. In the records of Tank Nos 13, 14 and 15 no increase in use occurred during the first month after the tanks were put in operation, the probable reason being that two or three weeks prior to taking the first records the soil was saturated throughout. Attention has been called to these tanks as check tanks to determine the difference in evaporation between disturbed and undisturbed soil. It w^as expected that in the rearrangement of the disturbed soil, the soil mass would be looser and the capillary spaces larger, with resulting greater evaporation. Refer- ence to Table 8 indicates that this was the case. The tabulated results show tluit the total mean eva]')oration from Tank Nos. 13, 14 and 15, containing disturbed soil, was 14.576 inches during the nine-month! period from August, 1929, to April, 1930, inclusive, and that there was! a mean evaporation of onl}- 3.729 inches from Tank Nos, 4, 5 and 6 during the same period. Table 9 sums up the monthly evaporation from water surfaces and the consumptive use of water by Bermuda grass in tanks at San Bernardino, The Mariotte Tank. Measuring the evaporation of water from bare soil surfaces or its consumptive use by vegetative growth in soil tanks is greatly simplified by the use of the INIariotte tank, as previously developed and used by members of the Division of Agricultural Engineering.* Previous to this develo])ment tlie study of soil moisture through the use of tanks necessitated weighing the tanks with their contents at intervals to deter- mine the amount of water lost. This method involved a number of * Experiments to determine rate of evaporation from saturated soils and river-bed sands, by Ralph L. Parshall, Senior Irrigation Engineer, U S. Department of Agri- culture ; Proceedings, American Society of Civil Engineers, April, 1929. i EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 129 03 < < fc H 05 -a -OT3 -a -a -a T3 i O O o s s o g s c« II s "o C3 C8 a o3 & bO ih tis M a rt e3 a c3 a s •T3T3 -o ■a -a T3 3 Z3 3 3 3 3 M a a a gg a fc^ b. t-t c ^ CO IT-i CO CO •» OCO c^ ■*-^co < im'^' —■ COC^ Cd id-H id ^ jOf, to CO >o OO CO Ico cot^ o ■* J- o -H 05 o OS jo s -< '-' '^ ^ CO 'lid u a< , t^cD CO coco CO CO Ico V) 2 ^ ■*t^ CO ■* t- o t^ 1 to OSO o CO o CO ■■«< 00 leo c u 3 OtO OO to CO •* O Ico >raoo CO to S3 < tooo t^ ■<*' -^ ■* CO 1 CO a C3 o o CO Ico »-s c »-■ Oi »-< o 1^ Oi OO O ico « i^ ^»< o -^ •4-> t-lr- t^ ooo o ■* 1 OO g '^i o £ u 3 t-i lOUO o — lO to •>»< lo ^1 »o o GO ■^ -H O 100 c^ to CO-* to l>. |CS CO ^ -* i-v ^ > 2 I. ^ 1 _ rtCO CO CO lo 1 t- 1 coco CO .OO t>- Ot^ CO TT 1 to (m" 1 co COCO CO id ltd CD -H 1 ^^ tot- ^ coco O O 1 o 00 CO CO coos Oi 1 OS to ■* toco O.J3 e« ! ei COCO CO idipio S ^ lO 1 lO •*o CO OCO 00 3 OCO ■a T)^ 00 o OS lOO TJ1 1 ■* r-t OO to 00 it^ •-^ tfj 1 lO t>ilO CO 00 los o CO->J< to t^ loo & o 1 o OO o o lo OO 1 -* -TJ* OS .00 s Cd CO 00 o o .t^ '^ 1 ■* id"* to CO .t- c5 i 1 ^; ; ; j>( 1 1 a I [ H i 1 i i 1 1 t-Ic-jI CO-* lOco't^ OC/3 co^ S 3J I--" I- «/) O) Oz ' < z o:< Oi/) Q. .0-.9 "l.^'f 1 On: ^ « « to x> a. ■♦- -} li c C 3 ravel and silt or clay. The coarser materials form the underground basin, from w^liich approximately 80 per cent of all the water used in the county for irrigation and domestic use is pumped, and the surface overlying this underground basin comprises the greater part of the agricultural area. The depth of the deposits is not definitely known, but well logs recorded in the southern portion show unconsolidated material at depths of 1000 feet and more. Underlying much of the agricultural area, tight silt or clay deposits, forming the impervious cap of an artesian basin more important formerly than now, occur at various depths. This practically water tight cap separates the waters of the underground basin from those on the surface and accounts for the perched water table found at various shallow depths throughout the area lying south and west of a line connecting the towns of Tustin, Santa Ana, Garden Grove, Stan- ton and Buena Park. North and east of this line the upward slope of the ground surface increases more rapidly and the perched water is found at greater depths. It is thought that at some point in this direction the clay cap disappears and the perched water table and the waters of the underground basin merge in one body at some lower level. It is known that the bed of Santa Ana River will absorb stream flow for several miles above the Chapman Street bridge, west of Orange, and that flood flows passing this point are not absorbed, but continue on to the ocean. Formerly large areas suffered from a high water table, supplied in part by artesian flow, and lands were of little value for cultivation, salt grass being the principal growth. As farming expanded and land values increased, numerous successful attempts were made to lower the surface water by drainage into the ocean, the surface water being held at depths which allowed sufficient root development for agricul- tural cropping. The result of the annual depletion of the underground reservoirs also is apparent in the drainage situation. Artesian wells ceased to flow and pumping at increased cost has become necessary, with the result that less water is used for irrigation and waste is cut to a minimum. Consequently drainage ditches do not carry as much water as they formerly did. Systems which flowed throughout the year now carry water only during the months immediately following the winter rains. Certain areas, however, notably the low peat area near Win- tersburg, have a continuous high water table, within two feet of the 142 DIVISION OF WATER RESOURCES ground surface. In the northwestern part of the county, also, salt grass, which is an indicator of ground water, is found more extensively than elsewhere. At the present time the perched water table apparently fluctuates through a yearly cycle, reaching a peak height in the spring after the rainy season and a minimum stage before the rains begin in the late fall. The ground supply is replenished by both rainfall and irriga- tion by pumping from the deeper levels, and is depleted by soil evap- oration, transpiration from crops and other vegetation and by artificial drainage. No use is now being made of the surface water, except from a few shallow wells constructed for domestic purposes. Irrigation pumping is entirely from the deeper underground basin. Long records of depths to water levels in used wells have shown that the present water table is much lower than the perched water level in the surrounding soil. Witli a serious shortage of water pos- sible within the next decade, if additional supplies are not procured, it may be desirable to conserve some of the surface water now wasted by evaporation, transpiration and drainage. For example, surface water collected by drainage systems could be diverted to adjacent deep wells or shafts and allowed to pass into the underground basin to replenish the failing supply. With electric power everywhere available, surface water could be pumped directly from shallow pits into existing drainage ditches through which it could flow to the con- necting wells. Thus surface waters might be stored below the possi- bility of further waste and made available for beneficial use, provided that the cost is reasonable. Surface Test Wells. In 1927 a representative of the California State Engineer began a study of the surface ground water conditions in western Orange County and established a number of test wells with a view to measuring the fluctuations of the perched water table. In general, these wells were located a mile or two apart, along east and west highways, and covered the greater part of the agricultural portion of the county. For a' time in 1928 records were kept by the Orange County Flood Control District and during 1929 by the Division of Agricultural Engineering of the United States Department of Agriculture, which in turn relinquished the taking of the records to the flood control dis- trict when its studies were resumed in 1930. The wells consisted of four-inch uncased holes bored from four to twelve feet deep. In sandy loam soils such wells would not stay open and it was necessary to rebore them for each reading. For various reasons, accurate and continuous records have been impossible in some places, but in general the results have given a very good picture of the fluctuations of the perclied water table and show the depths at which this water may be found in different localities at various seasons. This report includes only that part of the investigation during which records were kept by the Division of Agricultural Engineering, but the results obtained are representative of other years as well. During 1929 no rainfall of importance occurred after April, and in December the surface -water stood at the lowest point of the year. During January, 1930, the rainfall amounted to 5.55 inches, in Feb- ruary to 0.55 inch and in March to 2.99 inches. In most cases rains I i EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 143 amounted to less than one-half inch per 24 hours, but in January there was one rain of 1.57 inches and in March one of 1.72 inches. Neither one caused surface run-off and consequently all water which fell passed into the soil and a portion of it reached the perched water table. Prac- tically no irrigation occurred during the four-month period from December, 1929, to April, 1930, and the ground water replenishment was due entirely to rainfall penetration. The mean rise along any particular highway for the period indicated is given in Table 13. TABLE 13 MEAN RISE OF PERCHED WATER TABLE IN ORANGE COUNTY DUE TO RAINFALL BETWEEN DECEMBER, 1929, AND APRIL, 1930 Name of highway Number of wells measured Rise of perched water table in feet Orangethorpe avenue _ . Lincoln avenue Cerritos avenue Ocean avenue 3 3 4 6 6 10 4 0.7 1.1 0.9 1.5 1.5 Wintersburg avenue and Delhi road . Garfield avenue 2.0 2.2 Total number of wells and mean 30 1.4 The locations of highwaj^s and test wells and contour lines repre- senting depths below the ground surface at which the perched water table was found to lie in April are shown in Plate XI. In most cases the water contours parallel the general direction of the surface con- tours, but there are some exceptions due to soil conditions. Rainfall Penetration. In recent years a lowering of the perched water table underlying the 3500 acres comprising the Newhope Drainage District has been accomplished by the installation of several miles of drain pipe emptying into Santa Ana River. This district lies adjacent to the west bank of the river, in a narrow strip one or two miles in width extending about four miles southerly from the vicinity of Garden Grove as shown in Plate XI. Drains were laid at an average depth of from seven to eight feet and are roughly spaced about one-fourth mile apart. Test wells show that the perched water table now stands at from five to eighth feet below the ground surface throughout the district. The tract, an alluvial deposit of Hanford fine sandy loam and Hanford sand, sup- ports a thriving agricultural community. Late in 1929, a weir with water register was installed in Manhole 26 of the district drains, located on Smeltzer avenue, for the purpose of measuring the penetration of rainfall in this part of the district. It was estimated as nearly as possible from district maps that the drainage from 1900 acres could be measured at this point. As there has been no rain for several months and the volume of irrigation decreased throughout the latter months of the year, the drainage flow likewise decreased until it was at a minimum prior to the first rains of the sea- son early in January, 1930. That a better idea of the flow measure- 144 DIVISION OF WATER RESOURCES PLATE XI WESTERN ORANGE COUNTY SHOWING LOCATION OF SURFACE TEST WELLS WITH WELL NUMBERS AND SURFACE WATER CONTOURS FOR APRIL- 1930 Scale of Miles 2 3 4 s II'' / J EVAPORATION-TRANSPIRATION LOSSES FROM MOIST AREAS 145 ments may be given, Plate XII has been prepared showing the fluctuations of the drainage flow in acre-feet per day, the total amount of rainfall in inches on any particular day of the season, the accumu- lated increase in flow due to rainfall by five-day periods and the mean percentage of soil moisture above the water table at the nonirrigated site of the Santa Ana station, about midway of the district. The diag-ram shows the first rain of the season, on January 5, and the first increase in flow over the weir on January 9. In general, the daily flow increased folloAving each rain of one-half inch or more and decreased between heavy rains and also for periods following light rains. The accumulated increase in drainage flow due to rainfall begins at 0.38 acre-foot of flow per day, which was the minimum of the season, and builds up gradually from nothing to 67 acre-feet on June 1. Up to this time rainfall had been so distributed that practically^ no irrigation was necessary. The resumption of irrigation about June 1, contributed to the moisture already in the soil and caused an increase in flow not due to rainfall and for this reason further observations were discon- tinued. During the season the total rainfall amounted to 11.1 inches, as measured at the Santa Ana station, which, when computed over the entire 1900 acres drained, amounted to 1757 acre-feet. As but 67 acre-feet, or less than half an inch of rainfall, were measured at Man- hole 26 as increase due to rainfall penetration, the balance of 1690 acre- feet of rain which fell upon the drainage area can only be accounted for as soil storage, soil evaporation and transpiration from crops and other vegetation. The penetration of only 67 acre-feet out of a total of 1757 seems a surprisingly small amount to penetrate to a shallow depth through porous soil with a relatively high water table, but it must be remembered that during the entire period of five months only three storms, one in January, one in March and one early in Maj', occurred and caused immediate penetration to the depth of the drainage system. Each of these storms caused an increase in drainage flow. All other rains were light and the precipitation rapidly evaporated or transpired and did not have time to penetrate deeply into the soil. No doubt a part of the 1690 acre-feet unaccounted for remained in the soil at the time observations were discontinued and eventually reached the water table and should therefore be comited as penetration due to rainfall, and also undoubtedly a part of the total was evaporated or transpired from vegetation, but it is not possible to separate these various amounts. If soil moisture due to rainfall had not been increased by irrigation of crops, further measurements of drainage flow might supply more accurate data regarding total penetration. In December, prior to any rainfall, and following each of the heavy rains in January, March and May, soil moisture samples were taken at the Santa Ana station to determine soil moisture deficiency and field capacity of the soil at this point. This soil moisture deficiency is not representative of the entire area under consideration as the barren ground at the station is not irrigated and only receives rainfall to replenish the soil moisture, while surrounding cultivated areas receive both rainfall and irrigation. The soil moisture content would, therefore, be much greater throughout the 1900 acres of the district than at the station and the soil moisture deficiency would be less. Computations show that the deficiency at the station on December 9 averaged one 10—81141 146 DIVISION OF WATER RESOURCES inch per foot in the upper five feet of soil and was probably about the same at the end of the dry season early in January. Due to the Jan- uary storm the soil moisture nearly doubled and rose to about field capacity, increasing? very little during: the balance of the rainy season. This feature of Plate XI 1 is included merely to show that some of the moisture remained stored in the soil immediately above the water table and that a slow rate of drainage flow supplied by rainfall held in the soil might be expected to continue. PLATE XII 1.02 I I I — I — I — I — r — I — I — [ NOTE: Total area drained " rainfall on 1,900 acres Increase in drainage due To rainfall- 1,900 acres I I.I inches •• 1,757 acre-feet 67 " " soil storage plus evapo-transpiration plus an^ percolation- 1,690 acre-feet Soil is Hanford fine sand^ loam and Hanford sand. EFFECT OF RAINFALL PENETRATION ON 1900 ACRES OF NEWHOPE DRAIN- AGE DISTRICT AS MEASURED AT MANHOLE 26, JANUARY TO JUNE, 1930. APPENDIX PRECIPITATION RECORDS (147) PRECIPITATION RECORDS The United States Weather Bureau maintains stations scattered throughout the area studied and many other stations have been established in connection with this investigation in districts not imme- diately covered by the Weather Bureau. Records of rainfall intensity are available from two recording rain gages within the area. Gages were established in connection with all special plots so that records were available at the immediate locations under studv. Records for the 1927-28, 1928-29 and 1929-30 seasons are given for sixteen representative stations in the following tables: TABLE 1 RAINFALL DATA AT SANTA ANA U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches August 28 September 17 October 26-29 October 31... November 1 November 10 November 13-14 November 21 December 10-11 December 14-15 December 21-22 December 26-27 December 29-30 January 15-17 February 3- 5 March 3- 4 March 6... March 24-28 May 8-10 Totals 0.14 .04 .80 .36 2.90 .21 .13 .02 1.81 .69 .32 .62 .20 .29 2.33 .62 .86 .58 .28 13.20 October 12-13 November 13 November 15 December 3- 4 December 11... December 13-15 January 16-17 January 19-21 January 23 February 1- 4 February 6- 7 February 18-19 March 10-11 March 13 April 4- 5 April 19-.- June 17..- 0.55 .55 .87 1 06 .27 1.10 .58 .92 .05 1.01 .08 .28 1.58 1.00 .09 10.18 September 18-19 October 2... October 14-15 January 6- 7 January 10-16 January 18 January 27 January 29 February 21-22 February 24... February 28-29 March 3- 5 March 14-17 March 19... March 30-31 April 1... April 30..- May 1 May 3- 6 May 17--- 0.53 .04 .79 4.80 .13 .38 .18 .20 .33 .11 .57 3.63 .21 .08 .04 .32 .72 1.44 .03 14.56 (149) 150 DIVISION OF WATER RESOURCES TABLE 2 RAINFALL DATA AT TUSTIN U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 27-28 ... 0.74 .89 2.30 .22 .04 1.26 .56 .25 .58 .24 .31 1.48 1.39 .32 .15 .32 October 12-13 November 13-14 December 3- 4 0.54 1.53 1.01 .30 .76 1.62 .05 .59 .06 .45 .96 .06 .04 1.34 .05 .11 0.58 October 31 October 2 January 6- 7 January 9-16 .05 .79 3 85 December 13-15 January 16-21 .04 December 10-12 . . 01 December 14-15 December 22 January 27-28. February 21 .65 December 26-27 . February 1- 4. .10 February 23 .23 February 27 . -. . 11 January 15-16 February 3- 5 _ March 4- 6 March 14-17. March 19 February 18-19 March 10-11 March 13 .47 3.63 .08 March 31 .05 April 1 March 3- 5 March 24-25 March 22-23 April 4- 6 April 19 .26 March 27 April 30 .46 May 1 May 8-10 .78 May 3-5 1 51 Totals 11.05 9.47 13 65 TABLE 3 RAINFALL DATA AT CORONA U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-28 1.17 2.40 .35 .14 1.52 .20 .27 .75 .14 1.11 .01 1.96 .05 .45 .81 .28 .05 .01 October 11-12 November 13 0.85 .35 .47 .82 .17 .92 .41 1.04 .05 .64 .16 .50 1.05 .12 .15 1.14 .06 0.65 October 30-31 January 6- 7 January 9-16 January 26-27 February 21 .62 3.49 December 3- 4 December 9-11 .75 December 13-15 January 16-17 January 19-21 .05 February 23 - .55 .02 December 29-30 .40 January 14-15 January 22.. February 1- 5 March 14-17 March 30-31 April 30 2.48 .15 February 2- 4 1.45 March 10-11 March 13 May 1 .55 March 2- 3 May 4-5 May 16 1.18 March 24 .12 March 24 April 4- 6 April 19-20 March 27 Totals 11.67 8.90 12.46 PRECIPITATION RECORDS 151 TABLE 4 RAINFALL DATA AT CHINO American Beet Sugar Company 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-27 October 30 October 31... November 1 0.77 .75 1.77 3.29 .04 .47 .15 2.14 ,24 .36 1.03 .17 2.49 1.52 .97 .24 1.35 October 11-12 November 12-14 December 2-3 December 10 December 13-14 January 16-21 January 31 February 2- 4 February 7- 8 February 17-18 March 10-11 March 14 March 22 0.53 1 44 1.35 .21 1.04 2.21 .06 1.14 .10 .81 1.67 .07 .04 2.39 .07 .03 September 18... January 5-16 January 19. __ January 27-28 February 20-22 February 26 March 4.. _ 0.76 5.44 .03 .52 56 09 December 9-10-.. -._ .34 December 14-15 March 13-18 March 31 April 1 April 30... May 1- 6 May 16-17 4.07 11 December 25-29 January 15 February 2- 4 .03 .18 2.53 13 March 2-5 March 23-27 April 2 April 4-5 April 19 June 16 May 8- 9 Totals . 17.75 13.16 14 79 TABLE 5 RAINFALL DATA AT NAROD West Ontario Citrus Association, C. W. Fox, Observer 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-28 October 31 0.87 .60 1.75 .21 .38 .16 2.88 .26 1.21 .29 3.10 1.48 .10 1.45 .54 1.67 .02 October 12-13 November 13-15 _ December 3- 4_ December 11-14 January 16-21 February 2-6 February 19 March 10-13 March 19. ,_ March 22-23 April 4-5 April 20 June 17 0.32 1.25 1.04 1.41 1.83 .91 .69 1.59 .04 .19 2.21 .09 .33 September 18-19 January 6-19 January 27-28 February 21-24 February 27 0.64 5.81 .56 November 6 .81 .04 .36 March 14-18 March 31 April 30 May 1-6 May 16-17 3.77 December 26-30 January 15-16 February 3- 5 March 3- 6.. March 14 March 24-28 .13 .44 3.23 .29 AprU 3- 4 May 9-11 May 14 Totals 16.97 11.90 16.08 352 DIVISION OF WATER RESOURCES TABLE 6 RAINFALL DATA AT TWENTY-SECOND STREET, UPLAND J. R. Johnson, Observer 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-27 October 31 0.86 1.95 .10 .35 .27 2 37 .20 .81 .28 .26 3.44 1.10 .14 .82 .88 1.36 .12 October 11-12 November 13-14 December 2 December 10-14 January 15 January 19-20 February 1- 7 February 18 u.-- March 9-11 - March 19 March 22 April 3-5 April 18-19 June 16 0.72 1.47 .93 1.89 .86 1.35 1.67 .64 2.55 .05 .24 2.46 .17 .21 September 17 October 14 January 5- 7 January 10-16 0.48 .03 1.19 6.09 .04 December 9-14 December 21 December 26 January 27 February 23 February 27 -.. March 4 March 14-17. March 30-31 April 13... April 30 .52 .91 December 29-30 January 15-16 February 3- 4... March 3-5 March 13 March 24-26 AprU 2 May 8-10 .13 .64 3.75 .10 .07 1.84 May 1-8 May 16-17 2.68 .27 15.31 15.21 18.74 TABLE 7 RAINFALL DATA AT BASELINE AND HERMOSA AVENUES, ALTA LOMA L. A. Smith, Observer 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-27 October 31 November 5 0.84 1.93 .15 .35 2.57 .29 1.20 .28 3.33 1.11 .25 1.28 .82 1.38 October 12-13 November 12-14 December 2 December 10-12 January 15-16 January 19-20 February 1- 3 0.89 1.50 1.17 1.57 .74 1.67 1.27 .17 .74 2.14 .03 .23 2.11 .02 .20 September 17-.- January 5-15 41 7.15 .03 January 26-27 February 22-23 February 27 .53 December 9-10 December 13-14 December 23-29 January 14-15 .87 .16 March 4- 5 - March 14-17 March 30-31 April 30 .81 4.64 .38 February 2-6 February 18... - March 9-12 March 18 March 22 April 4-5 April 8 1.81 March 2- 5 March 13... May 1-4 2.31 March 24-27 April 2 .17 May 8-10 Totals 15.78 14.45 19.27 PRECIPITATION RECORDS 153 TABLE 8 RAINFALL DATA AT GUASTI Guasti Wine Company 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 26-28... 0.71 .40 1.82 .02 .32 .12 2.40 1.32 .45 2.85 .68 .15 1.08 .50 1.31 October 11-12 November 12-15 December 3 December 11-15 January 16-21 February 2- 4 February 19 March 11-13 March 23 April 4- 6 April 19 June 17 0.50 1.11 .75 1.21 2.29 .84 .73 1.64 .23 2.03 .06 .23 September 18 . 1.30 October 31 January 6- 7 January 10-18 January 27-28 February 21-23 .46 4 55 November 6 47 65 December 10-14 .39 December 27-30 March 15-18 March 30-31 April 30 May 1- 5 May 15 3.66 .84 February 3- 5 March 5- 6 __ March 14 March 23-27 April 3 May 9-10 .54 2.84 .11 Totals 14.13 11.62 15.81 TABLE 9 RAINFALL DATA AT WINEVILLE Charles Stern and Company 1927-28 1928-29 1929-30 Date of storm RainfaU in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 26-27 0.62 1.90 .10 ? .02 1.93 .22 .65 .60 .75 2.12 .90 .08 .63 .28 1.30 October 12 ... 0.58 .45 .53 .63 .94 .98 1.48 .64 .28 .58 1.20 .09 1.90 .00 0.60 October 31 ... January 5- 6 January 10-15 January 27 .28 3.88 .51 February 20-22 March 4 December 11-14 January 16 January 19-20 .58 .76 March 14-17 April 1 2.91 December 25-26 December 29 .20 February 4- 6 February 19 March 10 March 22 . . AprU 20 May 1- 4 .08 February 2- 4 3.25 March 3- 5 March 13 April 4..._ April 18 March 24-26 April 2 May 9-10 Totals 12.47 10.37 13.05 154 DIVISION OF WATER RESOURCES TABLE 10 RAINFALL DATA AT RIVERSIDE U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-28 October 30 1.25 2.27 .20 .02 1.13 .06 .31 .64 .20 .77 2.21 .62 .01 .20 .06 .10 .94 October 11-12 0.56 .37 .41 .48 .15 .84 .45 .94 .19 .34 .30 .52 .30 .06 .04 1.30 .16 .03 September 17-18 January 7- 8 January 10-12 January 18 January 27-28 February 21 0.63 .41 3 53 November 12 December 3 .09 .62 December 13-14 January 15-16 January 18-20 February 1- 2 February 4- 7 February 19 March 10-11 March 13 March 21-22 March 24 April 4-5 April 18-20 June 16.- .15 February 23-24 February 27 March 5 March 15-17 March 31 April 1 .44 December 25-27 .05 January 15-16- February 3- 4 .54 2.52 .21 .26 March 3-6... March 14 March 24.. --. March 26-27 April 30.-- May 1-5 May 9 .41 3.06 .08 April 3.-- May 7- 9 May 17 .07 Totals 10.99 7.44 13.07 TABLE 11 RAINFALL DATA AT ETIWANDA W. F. Barnes, Observer 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-27 0.71 2.28 .50 .33 2.10 .36 .26 1.11 .56 2.49 .78 .15 1.54 .88 .03 1.10 October 11-12 November 12-14 December 3- 4 0.60 1.34 1.52 .48 1.10 .73 2.01 1.85 1.10 2.15 .07 .25 2.31 .15 .22 September 18 49 October 31 . -- January 5-16 7.61 .56 February 20-23 February 27 .96 .26 January 15-16 January 19-21 February 1- 6 February 18... March 10 March 4. .. .89 December 25-29 January 15-17 February 3- 4 March 14-17 March 31 April 30 May 1-8 May 16-17 4.40 .46 1,90 2.60 March 3- 6 March 13 March 18 March 22 April 3- 5 April 19 June 16- .30 March 24-27 April 3 --- April 24..- May 9-12 -.. Totals 15.18 15.88 20.43 PRECIPITATION RECORDS 155 TABLE 12 RAINFALL DATA AT SAN BERNARDINO U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-29. October 31--.. November 1 November 6 November 10 November 13-14. December 10-12. December 14 December 21-22. December 25-27. December 28-29. January 15-16. February 3- 5. March 2- 6. March 13-14. March 24-25. March 27..- April 2.-. May 8-10 May 12.-- May 14 May 17... Totals 1.67 1.60 .66 .04 .23 .16 1.61 .10 .48 .57 .63 .74 2.65 .77 .16 .34 .03 .51 1.04 .02 .03 .01 14 05 October 11-12 November 13-15. December 3.-- December 11 December 13-14 January 16-21 February 1- 2 February 4 February 6- 7 February 18-19 March 9-10 March 13--- March 19--- March 23-24 March 30--- April 4- 6 April 18-19 June 16 0.82 1.10 .65 .43 .91 2.28 .59 .26 .30 .74 1.23 .02 .01 .32 .02 2.15 .26 September 5 September 18 October 28... January 5... January 7 January 9-16 January 18 January 27 February 20... February 22-23 February 26..- February 28--- March 5- 6 March 14-17 March 30-31 April 13--- April 15.-. April 30--- May 1- 5 May 7 May 16-17 0.01 .52 .05 .20 .25 4.06 .10 .51 .30 .80 .05 .01 .42 2.56 .82 .01 .02 1.05 2.21 .01 .10 14.06 156 DIVISION OP WATER RESOURCES TABLE 13 RAINFALL DATA AT REDLANDS U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches July 20 0.05 1.60 .81 1.24 .15 .04 1.30 .10 .60 1.19 .33 2.13 .77 .34 .11 .13 1.52 .05 .02 .04 October 3 October 12 November 13-15 December 3 0.03 .85 1.12 .66 .26 .82 .50 1.24 .60 .19 .27 .57 .71 .11 .05 .39 2.16 .32 .04 10 October 25-28 October 30 September 18 56 September 21 .03 January 5-16 January 18 4.75 December 11 December 13-14 .10 December 10-11 January 27 February 20 .72 .05 January 19-21 February 1- 2 February 23 .48 December 25-29 January 15-16 - February 3- 4..- March 3-6 March 24-25 March 27 .06 March 5 March 14-19 March 31 . . .52 February 6- 7 February 18-19 March 10-11 March 13 3.27 .64 April 1 .56 April 30 .- .42 March 19 May 1- 7. May 9 April 3 March 22-24. April 4- 6 April 18-19 4.01 .02 May 17 .10 May 8-10 May 14-15.. May 17 Totals 12.52 10.89 16.39 PRECIPITATION RECORDS 157 TABLE 14 RAINFALL DATA AT MOUTH OF SAN ANTONIO CANYON U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 25-28 0.95 .49 1.29 .07 .48 .27 2.51 .06 .25 .74 .08 .62 3.94 .43 .91 .43 .86 1.19 .01 .05 November 13-15 December 10-12 December 14-15 January 16-17 January 19-20 February 1- 4 February 6 February 18 March 9-10 March 13 March 22-23 April 3- 5 April 18-19 June 16 1.63 2.51 .06 1.29 1.40 2 02 .49 .81 3.38 .04 .17 3.19 .12 .17 September 18 0.50 October 31 .48 January 7 January 9-12 January 14-17 January 27 February 20... February 21-22 February 27-28 March 4- 5 March 14-17 March 30-31 April 13 April 29-30 May 1-8 May 16-17 81 November 6 4.45 1 81 November 12-13 December 10-12 December 15-16 .58 .01 1.01 .29 December 27-28 December 30 ... 1.41 January 15-17 February 3- 5 March 3- 4 March 6 4.44 .40 .07 1.97 4.38 March 14-18 April 3-4 May 9-10 May 15 June 18-19 .37 Totals 15.63 17.28 22.98 158 DIVISION OF WATER RESOURCES TABLE 15 RAINFALL DATA AT LYTLE CREEK U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm RainfaU in inches July 26 0.12 .92 2.41 .32 .90 .56 2.86 .24 .44 .66 .57 .70 4.18 .51 1.66 .33 2.09 2.46 .21 1.34 October 11-12 November 13-15 December 3- 4 December 10 1.20 1.50 3.26 .88 2.08 1.24 4.13 2.53 .92 1.36 1.29 4.70 .89 4.29 .07 .91 .52 July 18 0.08 July 31 09 October 25-27 October 31 September 18 January 5- 6 January 9-12 January 14-16 SO 1.33 December 12-13 3.03 5.66 .10 January 18-21 February 1- 2 .78 February 20-23 March 4- 6 March 14-17 March 31 2.56 December 25 27 December 29-30 1.36 January 16-17 February 3- 4 March 3 February 18-19 March 9-10 March 22-23 April 4- 6 April 9 5.47 .35 April 30 2.58 May 1-5 May 7 3.39 .41 March 13 April 19..- - May 16-17 .20 March 24-27 June 16 April 3 --- April 24 May 8-9 Totals 23.37 31.77 27.89 TABLE 16 RAINFALL DATA AT DEVORE RANCH U. S. Weather Bureau 1927-28 1928-29 1929-30 Date of storm Rainfall in inches Date of storm Rainfall in inches Date of storm Rainfall in inches October 26-28 1.27 .42 1.52 .18 .92 .83 2.49 .30 .46 1.27 .86 4.11 .52 1.21 .52 2.40 2.19 1.18 October 12-13 November 13-14 December 3- 4 December 12-14 January 16-17 January 19-21 February 3 1.14 1.43 2.94 3.20 1.07 3.96 3.06 .86 2 06 .96 5.62 .20 .80 3.16 .72 .28 September 18 96 October 31 January 6- 7 January 10 January 13-16 - January 27-28 February 22-24 February 26 November 1 1.24 3.00 6.18 .82 November 14 . 2.29 .20 February 28 - .32 March 5.. - March 15-16 March 31... December 26-30 February 4 1.28 January 15-17 February 3-6 February 6- 7 February 18-19 March 10-11 March 18 5.26 .92 April 1... .27 April 30 1.40 March 2-3 March 6 March 23-25 April 4- 6 April 19-20 June 16 May 1- 5 5 05 March 14 March 24-28 April 3- 4 May 9-10 Totals 22.64 31.36 29.19 PUBLICATIONS DIVISION OF WATER RESOURCES (159) 160 DIVISION OF WATER RESOURCES PUBLICATIONS OF THE DIVISION OF WATER RESOURCES DEPARTMENT OF PUBLIC WORKS STATE OF CALIFORNIA When the DeDartment of Public Works was created In July, 1921, the State Water Commission was iuee«e<]«d by the Division of Water Rights, and the Department of Engineering was succeeded by the Dlrlslon of Engineer- ing and Irrigation In all duties except those pertaining to State Architect. Both the DlTlslon of Water Bights and the Dlrlslon of Engineering and Irrigation functioned until August, 1929, when they were consolidated to form the Dlrlslon of Water Besources. 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. DIVISION OF WATER RIGHTS ♦Bulletin No. 1 — Hydrographic Investigation of San Joaquin River, 1920-1923. ♦Bulletin No. 2 — Kings River Investigation, Water Master's Reports, 1918-1923. ♦Bulletin No. 3 — Proceedings First Sacramento-San Joaquin River Problems Con- ference, 1924. ♦Bulletin No. 4 — Proceedings Second Sacramento-San Joaquin River Problems Con- ference, and Water Supervisor's Report, 1924. ♦Bulletin No. 5— San Gabriel Investigation— Ba.sir Data, 1923-102(). Bulletin No. 6 — San Gabriel Investigation — Basic Data. 1926-1928. Bulletin No. 7 — San Gabriel Investigation — Analysis and Conclusions, 1929. ♦Biennial Report, Division of Water Rights, 1920-1922. ♦Biennial Report, Division of Water Rights, 1922-1924. Biennial Report, Division of Water Rights, 1924-1926. Biennial Report, Division of Water Rights, 1926-1928. DEPARTMENT OF ENGINEERING ♦Bulletin No. 1 — Cooperative Irrigation Investigations in California, 1912-1914. ♦Bulletin No. 2 — Irrigation Districts in California, 1887-1915. Bulletin No. 3 — Investigations of Economic Duty of Water for Alfalfa in Sacra- mento Valley, California, 1915. •Bulletin No. 4 — Preliminary Report on Conservation and Control of Flood Waters in Coachella Valley, California, 1917. •Bulletin No. 5 — Report on the Utilization of Mojave River for Irrigation in Victor Valley. California, 1918. •Bulletin No. 6 — California Irrigation District Laws, 1919 (now obsolete). Bulletin No. 7 — Use of water from Kings River. California, 1918. •Bulletin No. 8— Flood Problems of the Calaveras River. 1919. Bulletin No. 9 — Water Resources of Kern River and Adjacent Streams and Their Utilization. 1920. •Biennial Report, Department of Engineering, 1907-1908. ♦Biennial Report, Department of Engineering, 1908-1910. •Biennial Report, Department of Engineering, 1910-1912. •Biennial Report, Department of Engineering, 1912-1914. •Biennial Report, Department of Engineering, 1914-1916. •Biennial Report, Department of Engineering, 1916-1918. •Biennial Report, Department of Engineering, 1918-1920. 'Beports and Bulletins out of print. Library at Sacramento, California. These ma; be borrowed by your local library from the CallfomU StaU PRECIPITATION RECORDS 161 DIVISION OF WATER RESOURCES Including Reports of the Former Division of Engineering and Irrigation -California Irrigation District Laws, 1921 (now obsolete). —Formation of Irrigation Districts, Issuance of Bonds, etc., 1922. -Water Resources of Tulare County and Their Utilization, 1922. -Water Resources of California, 1923. —Flow in California Streams, 1923. —Irrigation Requirements of California Lands, 1923. -California Irrigation District Laws, 1923 (now obsolete). -Cost of Water to Irrigators in California, 1925. -Supplemental Report on Water Resources of California, 1925. —California Irrigation District Laws, 1925 (now obsolete). -Gf-ound Water Resources of Southern San Joaquin Valley, 1927. —Summary Report on the Water Resources of California and a Coor- dinated Plan for Their Development, 1927. —The Development of the Upper Sacramento River, containing U. S R. S. Cooperative Report on Iron Canyon Project, 1927. -The Control of Floods by Reservoirs, 1928. —California Irrigation District Laws, 1927 (now obsolete). -California Irrigation District Laws, 1929 Revision. —Santa Ana Investigation, Flood Control and Conservation (with packet of maps), 192S. — Kennett Reservoir Development, an Analysis of Methods and Extent of Financing by Electric Power Revenue, 1929. —Irrigation Districts in California, 1929. A — Report on Irrigation Districts in California for the Year 1929, 1930. ■B — Report on Irrigation Districts in California for the year 1030, 1931. -Report on Salt Water Barrier (two volumes). 1929. -Report of Sacramento-San Joaquin Water Supervisor, 1924-192S. —A Proposed Major Development on American River, 1929. —Report to Legislature of 1931 on State Water Plan, 1930. A — Industrial Survey of Upper San Francisco Bay Ai'ea, 1930. -Santa Ana River Basin, 1930. -South Coastal Basin, a Cooperative Symposium, 1930. — Rainfall Penetration and Consumptive Use of Water in Santa Ana Valley and Coastal Plain. -Permissible Annual Charges for Irrigation Water in Upper San Joaquin Valley, 1930. ( -Permissible Economic Rate of Irrigation Development in California, 1930. -Cost of Irrigation Water in California. 1930. , Division of Engineering and Irrigation, 1920-1922. , Division of Engineering and Irrigation, 1922-1924. , Division of Engineering and Irrigation, 1924-1926. •Bulletin No. 1- •Bulletin No. 2- Bulletin No. 3- Bulletin No. 4- Bulletin No. 5- Bulletin No. 6- •Bulletin No. 7- •Bulletin No. S- Bulletin No. 9- ♦Bulletin No. 10- Bulletin No. 11- Bulletin No. 12- Bulletin No. 13- Bulletin No. 14- •Bulletin No. 18- Bulletin No. 18- Bulletin No. 19- Bulletin No. 20- Bulletin No. 21- Bulletin No. 21- Bulletin No. 21- Bulletin No. 22- Bulletin No. 23- Bulletin No. 24- Bulletin No. 25- Bulletin No. 28- Bulletin No. 31- Bulletin No. 32- Bulletin No. 33- Bulletin No. 34- Bulletin No. 35- Bulletin No. 36- Biennial Report Biennial Report Biennial Report COOPERATIVE AND MISCELLANEOUS REPORTS •Report of the Conservation Commission of California, 1912. •Irrigation Resources of California and Their Utilization (Bui. 254. Office of Exj). U. S. D. A.) 1913. •Report, State ■V\''ater 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. •R'eport 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. Francis Dam, 192S. Report of the Joint Committee of the Senate and Assembly Dealing With the Water Problems of the State, 1929. 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 the Joint Committee of the Senate and Assembly Dealing with the Water Problems of the State. 1931. •Reports and Bulletins out of print. Library at Sacramento, California. Tliese may be borrowed by your local library from the California State 11—81141 lf)2 DIVISION OF WATER RESOURCES PAMPHLETS Rules and Regulations Governing the Supervision of Dams in California, 1929. Water Commission Act with Latest Amendments Thereto. 1929. Rules and Regulations Governing the Appropriation of Water in California, 1930. Rules and Regulations Governing the Determination of Rights to Use of Water in Accordance with the Water Commission Act. 1925. Tables of Discharge for Parshall Measuring Flumes. 1928. General Plans. Specifications and Bills of Material for Six and Nine Inch Parshall Measuring Flumes. 1930. SU41 7-31 2650 < THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO 50 CENTS ON THE FOURTH DAY AND TO $1.00 ON THE SEVENTH DAY OVERDUE. 1D£C 16 \m FEB 2 6 1990 ^£B 2 6 1930 ^ RECEIVED v":t}FEB i^ i^^o PHY SCI LIBRARY NOV 12 NOV 8 ISiWb K^-CE»VcD IMUV >-^^ SCI ubrAb* ^EIPT W\{\R ''- '^ ^^ PHYS ;CJ UBI^ARY Book Slip-25TO-7,'53(A8998s4)458 lll'^98 water resoui'ces. La 'if PHYSICAL SCIENCES LIBRARY TC82k £2 A2 UBRAKT UNIVERSITY OF CAUFOBUtt PAVIS 111598 3 1175 00477 7036 ,1 hit ^mnMnH