^ THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS 4603 STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS PUBLICVTIONS OF THE DIVISION OF WATER RESOURCES EDWARD HYATT, State Engineer BULLETIN No. 44 SOUTH COASTAL BASIN INVESTIGATION WATER LOSSES UNDER NATURAL CONDITIONS FROM WET AREAS IN SOUTHERN CALIFORNIA PART I Report of a Cooperative Investigation by the Division of Irrigation, Bureau of Agricultural Engineering, United States Department of Agriculture. PART II Report of a Cooperative Investigation by the Water Resources Branch Geological Survev, United States Department of the Interior. 1933 LIBRARY UNIVERSITY OF CALIFORNIA DAV IS FOREWORD The value of water that can be put to beneficial use in southern California is so great that it seems advisable to call attention to existing wastage along streams and in other wet-surfaced areas of that region. Studies that have been made recently lead to the conclusion that the possibility of utilizing such sources of supply to advantage is worthy of the most serious consideration. This bulletin gives basic data which may be applied in evaluating water now wasted that might be put to profitable uses. The bulletin is in two parts: Part I, a report of investigations made by the Division of Irrigation, Bureau of Agricultural Engineer- ing, U. S. Department of Agriculture, dealing with the disposal of water by evaporation and transpiration in various parts of southern California, and Part II, a report of investigations made by the Water Resources Branch, Geological Survey, U. S. Department of the Interior, dealing with loss of water from Santa Ana River in lower Santa Ana Canyon. Both reports were made cooperatively with the Division of Water Resources, Department of Public Works, State of California. It is believed that the publication of these two reports will throw needed light upon the little-understood subject of waste of water through natural causes. ( 5 ) PART I CONSUMPTIVE USE OF WATER BY NATIVE PLANTS GROWING IN MOIST AREAS IN SOUTHERN CALIFORNIA By Harry F. Blaney (1) At stations in Santa Ana Valley and Coastal Plain near Santa Ana, Prado and San Bernardino, (2) In the Mojave River Area near Victorville, (3) In Coldwater Canyon near Arrowhead Springs, located in the San Bernardino Mountains, and (4) At Baldwin Park and other evaporation stations in southern California. TABLE OF CONTENTS PART I Page FOREWORD 5 LETTER OF TRANSMITTAL 15 ACKNOWLEDGMENT 16 ORGANIZATION, STATE DEPARTMENT OF PUBLIC WORKS 17 ORGANIZATION, UNITED STATES DEPARTMENT OF AGRICULTURE 18 Chapter I INTRODUCTION AND SUMMARY 19 Introduction 19 Summary 20 Santa Ana, Prado, and San Bernardino Stations 20 Victorville Station 23 Coldwater Canyon Investigations 24 Evaporation from free water surfaces 25 Chapter II INVESTIGATIONS IN THE SANTA ANA RIVER VALLEY AND COASTAL PLAIN 26 Santa Ana Station 26 Description of site 26 Station equipment 28 Method of filling soil tanks 29 The Mariotte tank 30 San Bernardino Station 32 Description of site 32 Station equipment 33 Prado Station 34 Description of site 34 Station equipment 34 Meteorological records 35 Operation of tanks 40 Sources of errors in tank experiments 40 Santa Ana Station 41 San Bernardino Station 45 Prado Station — 45 Protection from rainfall 45 Soil alkali in tanks 47 Consumptive use of water 49 Evaporation from soil surfaces in tanks 49 Use of water by salt grass — 50 Use of water by Bermuda grass 53 Use of water by tules and cat-tails 58 Use of water by willows 64 Use of water by wire rush 66 Adjustment factors 67 Soil characteristics 68 Mechanical analyses 6 8 Moisture equivalent 69 Porosity, specific yield and specific retention 70 Apparent specific gravity "2 Chapter III INVESTIGATIONS IN MOJAVE RIVER AREA 74 Procedure J6 Consumptive use of water 81 Chapter IV INVESTIGATIONS IN COLDWATER CANYON 88 Equipment 93 Controls 93 Flume for winter measurements 94 Flow recorders 96 ' Evaporimeter 97 Evaporation and transpiration losses along the stream channel 99 Loss from stream between controls 99 Loss from stream above the highest control 114 Comparison of use between controls with meteorological data 116 Yield of water from drained slopes on Arrowhead Mountain 119 (9) 10 CONTENTS — PART I Chapter V EVAPORATION PROM FREE WATER SURFACES 122 Baldwin Park Key Station 122 Miscellaneous evaporation records 124 PART II GROUND WATER SUPPLY AND NATURAL LOSSES IN THE VALLEY OF SANTA ANA RIVER BETWEEN THE RIVERSIDE NARROWS AND THE ORANGE COUNTY LINE 141 Table of Contents, Part II 142 PUBLICATIONS OF THE DIVISION OF WATER RESOURCES 173 CONTENTS — PART I 11 LIST OF PLATES Plate Page Geographical locations of stations Frontispiece I. Plan of Santa Ana Station 27 II. Mariotte tank connected to soil tank to maintain a constant water level in the soil and supply water, evaporated or transpired, Santa Ana station, 1929-1932 31 III. Board housing for Mariotte tanks at San Bernardino 33 IV. Circular metal covers to protect soil tanks from rainfall while allow- ing free circulation of air over the tank surface 4G V. Monthly use of water by salt grass in tanks having various depths to water table 52 VI. Bermuda grass in tanks in field of similar growth at San Bernardino. The tanks are in the center of the picture showing heavier growth 57 VII. Comparison of use of water by Bermuda grass at San Bernardino with that of salt grass at Santa Ana and evaporation from water in Tank No. 16 at Santa Ana_- 58 VIII. A. Tules growing in tank six feet in diameter at Santa Ana station, 1931, with small tanks of tules and cat-tails at the right GO B. Cat-tails growing in small tank, Santa Ana station, 1931 60 C. Tules growing in small tank, Prado station, 1931 60 IX. Hourly rate of use of water by tules, evaporation from standard Weather Bureau pan and air and water temperatures, Prado station 61 X. Willow tree growing in 6-foot tank, Santa Ana station, 1931 65 XI. Moist area along the Mojave River above the Upper Narrows near Victorville, California 76 XII. Plan of Victorville station 77 XIII. Arrangement for tank No. 2 to supply water and to measure amount of evaporation and transpiration 7S XIV. Arrangement for tank No. 3 to regulate supply of water and to measure amount of evaporation and transpiration 78 XV. A. General view of Victorville station, taken October 31, 1931 79 B. View taken October 31, 1931, of swamp where two tanks were located, the stadia rod being held between the two tanks 7 9 XVI. View of tank No. 1, taken October 31, 1931 80 XVII. Monthly evaporation and use of water from tanks No. 1, No. 2 and No. 3, February, 19 31-February, 1932 : 81 XVIII. Mean monthlv evaporation and use of water from tanks No. 1, No. 2 and No. 3 83 XIX. Aerial view of Coldwater Canyon showing location of the controls 89 XX. A. Alders in canyon bottom viewed from an overhanging cliff 91 B. Alders in canyon bottom about midway between the middle and lower controls 91 XXI. Middle Coldwater control showing 3-inch Parshall measuring fluVne and flow, recorder 93 XXII. Combination flume for measurement of water at both high and low stages 95 XXIII. Flow recorder installation at lower Coldwater control 96 XXIV. A. Evaporimeter with shallow black pan 24 inches in diameter 98 B. Evaporimeter showing weighing mechanism and record cylinder 9 8 XXV. Evaporimeter charts 99 XXVI. Fluctuation in the water table in Coldwater Canyon, September 7-15, 1932 100 XXVII. Flow at Middle Coldwater Canyon control, August 9-15, 1931 102 XXVIII. A. Drop in flow in Coldwater Canyon, August 11-12, 1931 103 B. Daily evaporation-transpiration cycle, Ontario willow and reed tank, September 11-12, 1930 103 XXIX. Use of water between controls In Coldwater Canyon and daily maxi- mum temperatures at San Bernardino during 1932 113 XXX. Comparison of loss of water from evaporimeter and air temperature near mouth of Coldwater Canyon, September 7-15, 1932 118 XXXI. East slope of Arrowhead Mountain draining into Coldwater Canyon — 120 12 CONTENTS — PART I LIST OF TABLES Table Page 1. Monthly temperatures, rainfall and miles of wind movement at Santa Ana station 36 2. Monthly temperatures, rainfall and miles of wind movement at Prado station 37 3. Monthly temperatures, rainfall and miles of wind movement at San Ber- nardino station 38 4. Rainfall by storms at Santa Ana station 39 5. Rainfall by storms at San Bernardino station 39 6. Installation data on tanks used at Santa Ana station 42 7. Installation data on tanks used at San Bernardino station 45 S. Analyses of station water supplies and water from annular spaces of soil moisture tanks at Santa Ana and San Bernardino stations 47 9. Alkali salt concentrations and pH values of composite soil samples from various depths in soil moisture tanks at the Santa Ana and San Bernar- dino stations 48 10. Relation of soil moisture to depth of water table in tanks at Santa Ana station 51 11. Record of weekly evaporation from soil and use of water by salt grass in tanks at Santa Ana, California, May, 1929, to September, 1930__Between 52-53 12. Record of weekly use of water by salt grass in tanks at Santa Ana, California, October, 1930, to November, 1931 Between 52-53 13. Summary showing monthly use of water by salt grass and tules and evapo- ration from soil and water surfaces, May, 1929, to April, 1930, in tanks at Santa Ana, California Between 52-53 14. Summary showing monthly use of water by salt grass, tules, cat-tails, willows and wire rush and evaporation from soil and water surfaces, May, 1930, to April, 1931, in tanks at Santa Ana, California__Between 52-53 15. Summary showing monthly use of water by salt grass, tules, cat-tails, willows and wire ru.sh, and evaporation from water surfaces, May, 1931, to April, 1932, in tank at Santa Ana, California Between 52-53 16. Record of weekly u.se of water bv Bermuda grass in tanks at San Bernar- dino, California, May, 1929, to September, 1930 54-55 17. Record of weekly use of water by Bermuda grass in tanks at San Bernar- dino, California, October, 1930, to November, 1931 56 18. Summary showing monthly use of water by Bermuda grass and evaporation from "water surfaces. May, 1929, to April, 1930, in tanks at San Ber- nardino, California Between 58-59 19. Summary showing monthly use of water by Bermuda grass and tules and evaporation from water surfaces, May, 1930, to April, 1931, in tanks at San Bernardino, California Between 58-59 20. Summary .showing monthly use of water by Bermuda grass and tules and evaporation from water surfaces. May, 1931, to April, 1932, in tanks at San Bernardino, California Between 58-59 21. Estimated consumptive use of water by tules and cat-tails in swamps based upon tank experiments and percentage of swamp use to tank use 63 22. Summary of tank investigations showing estimated annual consumptive use of water in moist areas •' 67 23. Mechanical analyses of soil from tanks at Santa Ana and San Bernardino stations 68 24. Moisture equivalents of soil from tanks at Santa Ana and San Bernardino stations 69 25. Comi>ari.son of the computed specific yield of soils in the absence of a water table with the observed specific yield of the same soils having high water tables — 71 26. Porosity, specific yield and specific retention of soils in tanks having high water tables 72 27. Apparent specific gravity of soils in tanks at Santa Ana and San Bernardino stations. 73 28. Monthly summary showing evaporation, consumptive use of water from tule tanks, use of water expressed in per cent of evaporation, wind move- ment, rainfall, and temperatures at Victorville station, February ], 1931, to February 28, 1933 82 29. Evaporation from free water surfaces in the Weather Bureau pan and tanks Nos. 1, 2, and 3, December 5, 1930, to January 29, 1931 85 CONTENTS — PART I 13 Table Page 30. Summary by months of mean t(^mperatures, wind movement, evaporation, and consumptive use of water from tule tanks Nos. 1, 2, ami 3, and use of water from tule tank No. 3 expressed in per cent of evaporation at Victorville station 87 31. Classification of trees between middle and lower controls in Coldwater C^an.Non 90 32. Cla.ssilication of trees between upper and middle controls in Ooldwater Canyon 92 33. Comparison of estimated loss by evaporation from stream and total loss between middle and lower controls in Coldwater Canyon, September S-14, 1932 101 34. Daily maximum and minimum temperatures in Coldwater Canyon of the air, the stream, and the water in the evaporation pan, September 8-14, 1932 101 35. Daily maximum and minimum discharges at middle and lower controls in Coldwater Canyon, August 1 to October 17, 1931 105 3G. Daily maximum and minimum discharges at each control in Coldwater Canyon, June 24 to November 3, 1932 106-107 37. Daily loss of water from the stream between middle and lower controls in Coldwater Canyon, August 1 to October 17, 1931 110 38. Daily loss of water from the stream between middle and branch controls and lower control in Coldwater Canyon, June 25 to November 2, 1932 111 39. Daily loss of water from the stream between the upper and middle controls in Coldwater Canyon, July 15 to November 2, 1932 112 40. Daily loss of water from the stream indicated by dips in discharge curve at middle control in Coldwater Canyon, August i to October 17, 1931 114 41. Daily loss of water from the stream indicated by dips in discharge curve at upper control in Coldwater Canyon, July 15 to November 2, 1932 115 42. Monthly mean maximum and minimum temperatures at the mouth of Cold- water Canyon, at Alpine, and at San Bernardino, June to October, 1931 and 1932 117 43. Loss of water from atmometers at Coldwater Canyon, July 18 to October 24, 1932 117 44. Com])arison of loss of water from atmometers, evaporimeter, and loss of water between middle and lower controls, September 8-14, 1932 119 45. Precipitation 1931-32 season 120 46. Monthly evafporation records at cooperative key station at Baldwin Park, California, 1932-1933 ___— 123 47. Monthly evaporation records at Santa Ana, California, 1929—1932. Observed by the Bureau of Agricultural Engineering, U. S. Department of Agri- culture 125 48. Monthly evaporation records at San .Bernardino, California, 1929-1932. Observed by the Bureau of Agricultural Engineering, U. S. Department of Agriculture 126 49. Monthly evaporation records at Prado, California, 1930-1933. Observed by the Bureau of Agricultural Engineering, U. S. Department of Agri- culture 127 50. Monthly evaporation records at Ontario, California, 19,28-1931. Observed by the Bureau of Agricultural Engineering, U. S. Department of Agri- culture 127 51. Monthly evaporation records at Victorville, California, 1931-1933. Observed by the Bureau of Agricultural Engineering, U. S. Department of Agri- culture 128 52. Monthly evaporation records near Pomona, California, 1903-1905. Observed by the Office of Experiment Stations, U. S. Department of Agriculture 128 53. Monthly evaporation records at Chula Vista, California, 1918-1933. Observed by the Weather Bureau, U. S. Department of Agriculture 129 54. Monthly wind movement at Chula Vista, California, 1918-1930. Observed by the Weather Bureau, U. S. Department of Agriculture 130 55. Monthly evaporation records at Riverside, California, 1924-1933. Observed by the Citrus Experiment Station, University of California 131 56. Monthly evaporation records at South Haiwee Reservoir, California, 1924— 1932. Observed by Bureau of Water Works and Supply, City of Los Angeles 132 57. Monthly evaporation records at Fairmont Reservoir, California, 1923-1932. Observed by Bureau of Water W^orks and Supply, City of Los Angeles. J 132 58. Monthly evaporation records at Silver Lake Reservoir, California, 1930- 1933. Observed by Bureau of Water Works and Supply, City of Los Angeles_ 133 59. Monthly evaporation records at lower Fernando Reservoir, Callfureau of Agricul- tural Engineering, U. S. Department of Agriculture. Respectfully submitted, Berkeley, California, June 3, 1933. Chief, Division of Irrigation, Bureau of Agricultural Engineering, U. S. Department of Agriculture. ( 15 ) ACKNOWLEDGMENT The aiithors acknowledge the assistance rendered by members of the Division of Irrigation of the Bureau of Agricultural Engineering, United States Department of Agriculture, especially Dean W. Blood- good, Associate Irrigation Engineer, Dean C. Muckel, Junior Civil Engineer, and H. W. Kistner, who assisted in the preparation of the manuscript, and A. Lincoln Fellows, Senior Irrigation Engineer, who edited it. The advice and assistance of Harold Conkling, Deputy State Engineer, is recognized. Acknowledgment is made of the assistance rendered by P. C. Ebert, Jarret Oliver, and K. R. Melin of the United States Geological Survey. W. P. Rowe of the Board of Water Commis- sioners, City of San Bernardino, and M. N. Thompson, Engineer of the Orange County Flood Control District, also rendered valuable assistance. Acknowledgment is made to A. S. Amaral of the Appleton Land and Water Company for providing the site for the experiment station at Victorville, of the courtesies extended by II. S. Ward of the Arrow- head Springs Company in the ColdAvater Canyon Investigations, and to the Los Angeles County Flood Control District and San Gabriel Valley Protective Association for furnishing the site for Baldwin Park Key Station. Scientific names for native plants were determined at the Herba- rium of the University of California. ( 16 ) ORGANIZATION STATE DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES Earl Lee Kelly Director of PuUic Worlis Edward Hyatt State Engineer The South Coastal Basin Investigation was conducted under the supervision of Harold Coxkling Deputy State Engineer 2 — 4503 ( 1^ ORGANIZATION UNITED STATES DEPARTMENT OF AGRICULTURE BUREAU OF AGRICULTURAL ENGINEERING DIVISION OF IRRIGATION Cooperating in South Coastal Basin Investigation AV. AV. McLaughlin Chief of Division This report "was prepared by Harry F. Blaney Irrigation Engineer Assisted by Colin A. Taylor Assistant Irrigation Engineer A. A. Young Assistant Irrigation Engineer Harry G. Nickle Junior Hydraulic Engineer ( IS ) CONSUMPTIVE USE OF WATER BY NATIVE PLANTS GROWING IN MOIST AREAS IN SOUTHERN CALIFORNIA By Harry F. Blanet * CHAPTER I INTRODUCTION AND SUMMARY INTRODUCTION In southern California the natural water supply is exceedingly limited, while the demands for water are great and its value is high. In some sections the value of continuous-flow gravity water ranges from $100,000 to as much as $200,000 per second-foot,** depending upon its use. Both present and future agricultural, domestic, and industrial development depends upon the adequacy of the water supply. Under these circumstances it is economically important to utilize the available water supply to the fullest extent. For this reason federal, state, county, city, and other agencies are working along lines to deter- mine ways and means by which water, now wasted, may be conserved for beneficial use. The Bureau of Agricultural Engineering in cooperation with vari- ous agencies is making studies to determine the contributions of rainfall to the ground water of valley floors, consumptive use of water by plant life on both irrigated and nonirrigated lands, irrigation water require- ments of different crops, replenishment of underground storage of water by spreading, evaporation losses, and noneconomic use of water by native plants growing in moist areas. This report deals with the consumptive use of water by various types of indigenous vegetation commonly found in meadows and swamps and along stream beds, evapo- ration losses from soils without vegetative growth in areas of high water table, and evaporation from free water surfaces. In considering the adequacy of public water supplies in the past, too little attention has been given to use of water by noncrop plants. In most instances such plants are so located that they get their supplies of water before settled communities get theirs, and therefore such use must be considered in estimating water available for other purposes. For areas where large amounts of money are spent to develop and deliver water for irrigation at heavy annual cost to the irrigators, the water that could be saved by preventing the growth of uneconomic plants may be reckoned as approximating in value that of an equal amount of water in storage. For citrus fruits the cost of water is frequently as high as $15 to $20 per acre-foot and in some instances it is much higher. Tules, willows, and alders growing in irrigation canals, drainage ditches or stream channels or on their banks are usually exposed in narrow strips to sun and wind so that their consumption of * Irrigation Engineer, Division of Irrigation, Bureau of Agricultural Engineering, U. S. Department of Agriculture. ** State of California Department of Public Works Bulletin No. 36, Cost of Irrigation Water in California, by Harry F. Blaney and Martin R. Huberty. (1930.) ( 19 ) 20 DIVISION OF WATER RESOURCES water is very liiyli. Linin<>' canals to check see})a^'e losses and' diverting stream flows into conduits conserve water by eliminating losses due to such aquatic growths as well as by decreasing the seepage. In many instances irrigation and domestic supplies are obtained by diverting water from the lower reaches of canyons, the bottoms of which usually are covered with vegetation. The amount of water lost through consumptive use by that vegetation may be of considerable importance where the flow of the stream is relatively small and studies have therefore been undertaken to measure such losses. Evaporation records from standard Weather Bureau pans are valuable in estimating evaporation losses from reservoirs and consump- tive use of Avater by native vegetation growing in moist areas. Very few data have been published on evajjoration in southern California, accordingly all available records are included in this report. Among these are those kept by the Bureau of Agricultural Engineering at several stations in cooperation with the State Engineer of California and those kept in other localities by local agencies. SUMMARY Commencing in 1929 and continuing thereafter investigations of evaporation and transpiration losses in moist areas have been conducted by the Division of Irrigation, Bureau of Agricultural Engineering, United States Department of Agriculture, in cooperation with the Division of Water Resources, Department of Public Works, State of California, and other agencies. Stations were established at Santa Ana, Prado, San Bernardino, Victorville, Coldwater Canyon and Baldwin Park. The results obtained are summarized in the following discussion. Santa Ana, Prado, and San Bernardino Stations Data regarding evaporation from bare uncultivated soil and use of w^ater by noneconomic native growth found in moist areas in Santa Ana River Valley have been collected for the three-year period immedi- ately preceding May 1, 1932. Results of the first year's work have already been published.* Investigations were conducted at three sta- tions, although the greater part of the work was done at Santa Ana, with smaller stations at San Bernardino, 50 miles distant, and at Prado, midway between the other two. The Prado station w^as established a year after the others and work there is being continued. The other two stations have been dismantled. The soil at the Santa Ana station is classed as a Hanford fine sandy loam** and that at San Bernardino as Chino silt loam. The work at Prado did not include soil moisture studies and the soil class was not determined. The investigation included studies of evaporation from soil, consump- tive use of water by salt grass and Bermuda grass in tanks wdth pre- determined water levels, use of water by tules and cat-tails in submerged soil, and by willow and wire rush. Some experiments in evaporation from water surfaces also were included. Soil evaporation and use of water studies were carried on at Santa Ana in unbroken columns of soil in 12 tanks and with disturbed soil in three tanks. All soil moisture * California State Department of Public Works Bulletin No. 33, Rainfall Pene- tration and Consumptive Use of Water in the Santa Ana River "Valley and Coastal Plain, bv Harrv F. Blaney, C. A. Taylor, and A. A. Young. ** Soil Survey of the Anaheim Area, California. Bureau of Soils, U. S. Depart- ment of Agriculture. WATER LOSSES FROM WET AREAS 21 experiments were carried on in triplicate to average errors and the effects of soil differences. The following: snmraaries and conclusions are given from the data obtained during the investigation : 1. ^Mariotte tanks Avere nsed with all soil tanks to supply and main- tain a constant water table in the soil. Their value lies in the ease with which periodic measurements of water used may be made as they are automatic in operation. Great care is necessary to protect the ^Mariotte tank against temperature changes or from leakage of air into the tank or the connecting pipe system. 2. Evaporation tests from bare soil were conducted with both dis- turbed and undisturbed soil in tanks, separately. No evaporation occurred from tanks of undisturbed soil having a water table 4 feet below the surface. When the water table was raised to 3 feet from tlie soil surface the evaporation averaged 0.1 acre-inch per acre per month. Tanks of undisturbed soil having water tables at a depth of 2 feet lost an average of 0.445 acre-inch per acre per month for 15 months. In contrast with losses from undisturbed soil, three tanks filled with dis- turbed soil having a 2-foot depth to water level had a mean monthly loss by evaporation of 1.599 acre-inches per acre, while the average loss from undisturbed soil for the same period was 0.404 acre-inch per acre, or about 25 per cent. In disturbed soil the opportunity for evaporation was greater as the soil contained more moisture. Evapora- tion from undisturbed soil is more comparable to that lost under field conditions than is that from disturbed soil. These data indicate that there will be no evaporation from the light textured soils of the Hanford series when the water table is 4 feet or more below the ground surface. 3. Use of water by both salt grass and Bermuda grass was influ- enced by the availability of moisture in the soil and the depth to water table. Grasses in tanks having the highest water tables used the most water. During the year ending April 30, 1932, salt grass grown in tanks having water tables 1 foot in depth used water at the rate of 42.75 acre-inches per acre; with a 2-foot depth, 36.23 acre-inches; and with a 5-foot depth, 22.12 acre-inches per acre. In general, the ratio of the use of water to depth of water table b}* Bermuda grass was about the same as that of salt grass. From these data, it is concluded that use of water by these grasses is not excessive and does not exceed the amount that would be used by many cultivated crops grown under the same conditions of soil moisture. 4. Consumptive use of water bj- tules or cat-tails grown in tanks in exposed locations is not closely indicative of the true use by these plants growing in their natural environment. Growths in exposed tanks are subject to greater solar radiation, lower humidity and greater wind movement conditions than are found under natural swamp condi- tions; and use of water by swamp growth transplanted to exposed locations is inordinately high. Numerous instances of tules in tanks using an acre-inch or more of water per 24 hours at the Santa Ana station and an extreme use of 3.6 acre-inches per acre per 24 hours at Prado were noted. Taken as a percentage of evaporation from a standard Weather Bureau pan the use of water by tules or cat-tails in exposed tanks varied from 168.3 per cent for cat-tails at Santa Ana to 451.7 per cent for triangular stem tules at Prado. From other experi- ments bv the Bureau of Agricultural Engineering it is evident that 22 DIVISION OF WATER RESOURCES if the size of tanks was extended to swamp areas the consumptive use would decrease to a relatively small fraction of that used by exposed tanks. Very little is known as to the proi^er factor to be applied, but a limited investigation indicates that consumptive use of water by tules or cat-tails in densely grown natural swamp areas may be as low as 30 per cent of the consumptive use by similar growth in isolated tanks having extreme exposure to the elements. 5. Willow uses more water than either of the two wild grasses with which tests were made. A single clump of willow used 52.71 acre-inches per acre with a water table at a depth of 2 feet during an eleven-month period. This was 83.5 per cent of the evaporation from a standard Weather Bureau pan. The willow was fully exposed and the consumptive use may have been higher than would be the case from an area of equal size in a willow thicket. As a moist area noneconomic growth, the willow is responsible for Avaste of water which might other-wise be put to a more beneficial use. On the other hand, willows will grow in gravelly river bottoms Avhere they furnish protec- tion against erosion. Any benefit obtained by removal of such protection to increase the water supply may be offset by damage by floods carrying sand and gravel into valuable farm communities. No data are available indicating a factor for reduction of consumptive use by wdllow^s grown in exposed and isolated tanks to that used by natural growth in large areas. 6. Wire rush grows in a limited area in the Santa Ana Valley where high ground water exists. Its consumptive use measured from a 2-foot water table is high, exceeding that from grasses or willow. In July, 1931, it amounted to 13.75 acre-inches per acre, which was 2.8 times the amount used by salt grass during the same period and grow- ing at the same location. As far as is known, wire rush has no value for live stock and the water it consumes is an economic loss. No data exists for determination of a factor to reduce consumptive use from tank growth to that by natural field groAvth, but some factor should be applied. 7. Soil tests were made to determine mechanical analysis, moisture equivalent, porosity, and apparent specific gravity of soils in tanks. About 20 per cent of the soil at the Santa Ana station was fine enough to pass a No. 200 screen. Soil in the San Bernardino tanks was considerably finer. Moisture-equivalent values as determined at Santa Ana were not constant, varying from 5.8 to 13.0 per cent in different tanks. The moisture equivalent of the top foot of soil at San Ber- nardino was about 30 per cent, or nearly twice that of the subsoil at a depth of 3 feet. Porosity tests of soil in tanks show an average of 40.2 per cent at Santa Ana and 47.4 per cent at San Bernardino. 8. Specific yield and specific retention in relation to high water tables, the sum of the two equaling the total porosity, also were deter- mined. Each of these varies with the depth to the water table, the greater yield occurring with the least depth, and the greater retention with the greater depth. Porosity of the disturbed soil is about the same as in the undisturbed soil, but the specific yield is much less and specific retention is correspondingly greater. In the Chino silt loam at San Bernardino, the specific yield is small in comparison with the specific retention. The percentages measured as specific yield and WATER LOSSES P^ROM WET AREAS 23 specific retention are apparent rather than real, as they apply only to conditions of hi^-h water table. True values can be obtained only when measured from a high colunui of soil, disregarding the fringe of capillary moisture. 9. Alkali deposits occurred on the surface of several soil moisture tanks at the Santa Ana station, depending in amount on the depth to water table in the tank, ^luch of this alkali was originally present in the soil, but it was increased by the small amounts in solution in the water consumed. During the first two seasons, when the soil tanks were covered during rain storms. th(> concentration of alkali on the surface increased month by month. During the third season, much of the surface deposit was carried back into the soil by rainfall pene- tration, causing a redistribution. Chemical analyses of soils taken from the tanks at the end of the investigation show a high pH value and where the water table was close to the tank surface a very high con- centration of salts in the top inch of soil. As salt grass is alkali resistar:iC it is doubtful if the rate of transpiration was affected. Alkali was very much less in amount at the San Bernardino station, and no deposits occurred on the tank surfaces. Water used in the tests was from an artesian well and was relatively pure. The distribu- tion of salts was greater in the top soil, decreasing in amounts toward the water tables. The same was true of the pH values. Victorville Station . In November, 1930, an experiment station was established near Victorville for the purpose of measuring evaporation and transpiration losses from moist areas along the Mojave River and for recording meteorological data. The work was correlated with the stream flow measurements being made by the U. S. Geological Survey to determine the consumptive use of water between gaging stations at several loca- tions on the river. The experiment station was located in and on the bank of a small cienaga on the east side of the IMojave River. The equipment consisted of three tule tanks, a standard Weather Bureau evaporation pan, an anemometer, a set of standard maximum and minimum thermometers and a thermograph housed in a standard shelter, a rain gage and a ground well. Previous investigations regarding consumptive use of water by native A^egetation along stream channels* indicate that if data from tanks are to be used in estimating losses from larger areas under field conditions, the tanks should be set in a field of natural growth similar to that in the tanks. Two tule tanks were therefore placed in the swamp, one 2 feet in diameter and the other 6 feet in diameter. A third tule tank, similar to those used at the Santa Ana, Prado, and San Bernardino stations, was set in the ground on the bank for the purpose of demonstrating the effect of exposure on the use of water by plants grown in tanks. The standard Weather Bureau evaporation pan was also placed on the bank with similar exposure. Observations were made on evaporation, consumptive use of water from tules, "u-ind movement, rainfall, and temperatures from Febru- ary 1, 1931, to February 28. 1933. The results indicate the following conclusions : * California State Department of Public Works Bulletin No. 33, Rainfall Pene- tration and Consumptive Use of Water in the Santa Ana River Valley and Coastal i'lain, by Harry F. Blaney, C. A. Taylor, and A. A. Young. Chapter 4. 24 DIVISION OF WATER RESOURCES 1. Based on the 25-month period of record, the mean annnal con- sumptive use of -water by tules growing in a tank 6 feet in diameter, located in a swamp with natural conditions replicated, was found to be 78.5 acre-inches per acre. 2. For the same period, the mean annual evaporation from a standard Weather Bureau pan located on the bank near the swamp was 82.5 inches. By applying a conversion coefficient of 0.7 to this value, the mean annual evaporation from a lake surface is indicated to be 58 inches. 3. The ratio of the mean annual consumptive use of water by the tules to the mean annual evaporation from the standard Weather Bureau pan for the period of record is 0.95. 4. Based on the mean record for the two growing seasons from ]\Iay to October, inclusive, the evaporation from a lake surface is indicated to be 40 inches, while for the same period the consumptive use of water by tules would be 62 acre-inches per acre. This exceeds the loss by evaporation from the free water surface of a reservoir by 22 inches. 5. The investigation demonstrates the impracticability of applying to field conditions records of tests made in isolated tanks of tules grown apart from their natural environment. Coldwater Canyon Investigations The investigation into the lo.sses (tccurring along the stream chan- nels above the usual points of diversion was started in Coldwater Canyon near San Bernardino in 1931 and continued through 1932. The combined evaporation and transpiration by the native vegetation grow- ing in the canyon was determined by accurately measuring the water at various points along the channel. The controls were on bed rock so that the amount of water entering the upper end of each section of channel was known as well as the amount leaving each section. The losses from two sections of the canyon are reported, the average elevation above sea level of one being 2400 feet and of the other 2800 feet. The average width of the canyon bottom fill in the lower section is 49 feet, and in the upper section it is 44 feet. The results of this study show a loss from the lower section of the canyon of 72 acre-inches per 1000 feet of canyon for the six-month period from May to October, inclusive, 1932. This is at the rate of 64 acre-inches per acre of canyon bottom fill. For the same period in the upper section of canyon, the loss was found to be at the rate of 50 acre- inches per acre of canyon bottom fill. The evaporation from the water surface in the stream is shown to he only a small part of the total loss by evaporation and transpira- tion. The water surface of this stream is almost completely shaded and the evaporation rate would be greater in open areas where the water surface is exposed to the sun. The maximum loss in the canyon occurred during the month of August. 1932, being at the average rate of 0.44 acre-inch per acre per day in the lower section, and 0.35 acre- inch per acre per day in the upper section. In October the average rate of loss was 0.26 acre-inch per acre per day in the lower section and 0.20 acre-inch per acre per day in the upper section. Enough water is consumed during the growing season along each mile of canvon similar to the lower section to meet the annual irrigation WATER LOSSES PRO:\r WET AREAS 25 requirements of approximately 16 acres of citrus. For the upper section, the loss in each mile wonld meet the irrigation requirements of 11 acres of citrus. Evaporation from Free Water Surfaces The Bureau of Agricultural Engineering' has been keeping evapora- tion records at several stations in southern California in cooperation with the State Division of Water Resources, since 1928. Other agen- cies also have been making observations. These agencies do not always use the same type of evaporation pan and results from the different types are not comparable. For this reason a cooperative, experimental key station has been established at Baldwin Park for the purpose of correlating the data being collected by the various organizations and for determining factors that may be used to reduce the observations on various types of evaporation pans to a comparable basis. This inves- tigation is expected to continue for several years, until sufficient data are available for the purpose. The Los iVngeles County Flood Control District, the 8an Gabriel Valley Protective Association, the Pasadena Water Department, the California State Division of Water Resources, and the United States Geological Survey are cooperating with the Division of Irrigation, U. S. Bureau of xVgricultural Engineering, in conducting this investigation. Three types of evaporation pans have been installed at the station : 1. Standard Weather Bureau pan, 4 feet in diameter by 10 inches deep, set upon a wooden platform above ground. 2. U. S. Bureau of Agricultural Engineering type, 6 feet in diam- eter by 3 feet deep, set 2.75 feet in the ground. 3. Los Angeles County Flood Control District type, 2 feet in diameter by 3 feet deep, set 2.75 feet in the ground. Records of evaporation from free water surfaces in pans and tanks, collected by various agencies in southern California, are tabulated in Chapter V. AVith few exceptions all records of evaporation are comparatively recent, the majority being obtained since 1929. The oldest record available, that at Pomona, was of short duration — from 1903 to 1905. One record Avas begun at South Haiwee Reservoir, Inyo County, in 1924, and one at Fairmont Reservoir in Antelope Valley in 1923 by the City of Los Ajigeles. Both records are continuous to the present date. The longest record available is at Chula Vista, San Diego County, main- tained bv the U. S. Weather Bureau continuouslv since 1918. CHAPTER II INVESTIGATIONS IN THE SANTA ANA RIVER VALLEY AND COASTAL PLAIN By A. A. Young * This chapter deals ^vHh. the consumptive use of water in the Santa Ana River basin by varions types of moist area native vegetation commonly found along stream beds, swamps and cienagas, and the evaporation from moist soil without vegetative growth. As originally outlined the plan of the investigation was to deter- mine by tank experiments the use of water by wild grasses, and evapo- ration from bare soil in moist areas. Two experiment stations were established, one at Santa Ana and one at San Bernardino in 1929, and a third, at Prado, was added in the following year. In the vicinity of each are certain areas with relatively high ground water supporting moist area native growth from which samples were selected for trans- planting into tanks for study. A progress report giving results of studies at Santa Ana and San Bernardino stations of consumptive use of water by salt grass and Bermuda grass, and evaporation from uncultivated bare soil for the year ending May 1, 1930, has been published.** Since that bulletin was M-ritten several changes and additions have been made to the original set-up and the experiments have been extended to include the measurement of consumptive use of water by round stem tules and triangular stem tules, cat-tails, wire rush and willows grown in tanks. These studies were continued for an additional two years following the published progress report in 1930, and the data assembled during that period are presented herewith as a final report! of the investigations made. SANTA ANA STATION Description of Site Following a survey of western Orange County early in 1929, in which a study was made of soil type and soil moisture conditions, a small plot of ground was selected as the site for the Santa Ana experi- ment station for studies of consumptive use of water by moist area vegetation. The plot is in a level 10-aere field of small native vegeta- tion, 4 miles west of Santa Ana and about 7 miles inland from the coast. It is free from windbreaks and shade and is generally suitable in regard to soil, climatic conditions, and exposure to the elements for the studies undertaken. The station ground is 50 by 100 feet and is surrounded bj' a tight woven Avire fence for protection. Plate I is a general plan of the station showing the arrangement and uses of the various tanks. * Assistant Irrigation Engineer, Division of Irrigation, Bureau of Agricultural Engineering, U. S. Department of AgricuUure. ** Part II. Bulletin No. 33, Rainfall Penetration and Consumptive Use of Water in the Santa Ana River Valley and Coastal Plain. 1930. State of California, Department of Public "Works, Division of Water Resources. t Credit is due to Dean C. Muckel, Junior Civil Engineer, Bureau of Agricultural Engineering, for valuable assistance in collection of data from October, 1930, to December, 1.931, and in preparation of the report. (26) WATER LOSSES FROM WET AREAS 27 PLATE I \y 50 feet I I 1 , 23/ie Thermometer Shelter 2 o---e---------0 3 0---0------------------0 4 o=-Q---- ----- -=0 O— -— ------S-----0 13 to 50---S------0 ^ 0^'-"-"-"'-"^"-~0'^ 6 0-- -B-- ---------- -O O"-"' =--"-"Q-"^"0 15 — O Rain^a^e 7 0--€3-- 8 0----Q- BO--U- -o --0 II o-o---— ------ o 21 O 220I i2 0-^-====--^0 19 O leQ 23"Evap.tank •7 0 ^ G-O" -* 18 O Oil tests Well Tules 24 -n Willow 250 Y/ire rush 20 ( ) 4 ft. Pans Anemometer No. 488 PLAN OF SANTA ANA STATION. 28 DIVISION OF WATER RESOURCES The climatic conditions at this point are representative of the coastal climate of southern California. Summers are warm and dry while winters are moderate. Coastal fog's are of frequent occurrence and tend to modify evaporation from water surfaces and transpiration losses by plants. Soil at the station is of alluvial origin, classified as Ilanford fine sandy loam which grades into coarse yellow sand at a depth of 6 to 7 feet.* It is probably lacking' in humus and contains a small amount of alkali although not enough to affect the growth of the type of vege- tation under investigation. An ample supply of good water for use in the experiment tanks was found at a depth of a few feet. Station Equipment The equipment first installed early in 1929 consisted of 12 soil tanks, each connected to a IMariotte supply tank, a set of maximum and minimum thermometers and a thermograph set in an instrument shelter, a standard rain gage, a standard Weather Bureau evaporation pan, a circular sunken evaporation tank of the same diameter as the soil tanks and a shallow well with a hand pump to supply water for the various tanks. Later, two anemometers and three additional soil tanks with Mariotte control were added, making 15 soil tanks in all. Soil tanks are of the double type with an annular space between the inner and outer shell. The inner tank, 23^^ inches in diameter by 6 feet in depth, is suspended in the outer tank by means of a heavy angle-iron rim around the top. The bottom of the inner tank is removable and bolted in place by long rods to the supporting top rim. The inner tank holds soil, and the outer is a reservoir for water Avhich passes into the soil through perforations in the tank wall and in the bottom plate. Each soil tank unit is connected by a pipe to a INIariotte supply tank which regulates the height of the water table in the annular space between the inner and outer tank walls and supplies water to the tank growth as needed. From time to time additional tanks of simple construction were added in which tules, cat-tails, willows and wire rush were grown in order to measure consumptive use of water by each variety. One tule tank and one tank for willows were each 6 feet in diameter by 3 feet deep. Smaller tanks, used for other swamp growth, were each 25 1 inches in diameter by 2.7 feet deep. Each of the 6-foot tanks used water in such quantities that it was necessary to provide them with supply tanks equipped with automatic feed control to provide watey as needed, and at the same time hold the water level in the crop tank at a constant level. This could have been accomplished by i\Iariotte con- trol, but in this case a needle valve operated by a float was found satisfactory. When the water surface in the crop tank dropped, due to transpiration and evaporation losses, the float dropped also, opening the needle valve and admitting more water. When the water surface returned to its original level, the valve closed and the flow ceased. A water glass and a graduated scale on the side of tlie supply tank allowed readings of amounts of Avater Avitlidrawn. This type of control has been in use at all three stations during the investigations. * Soil Survey of the Analiiim Area. California. Bureau of Soils, U. S. Depart- ment of Agriculture. WATER LOSSES FROM WET AREAS 29 The evaporalioii pan was set upon a \v()()(U'ii grillage in accordance with iiistnictions issued by the Ignited States AVeather Bureau for pans of this type. Evaporation losses Avere measured by a hook gage gradu- ated to thousandths of a foot and mounted on the side of the pan. At the northwest corner of the grillage an anemometer was mounted on a stand so that the level of the cups was about V2 inches above the top of the pan and about 24 inches above the ground surface. Originally, a second anemometer was set 12 inches above the ground surface, mid- way in the row of soil tanks, to measure ground winil, but it was used only during the tir.st year of the investigation. Method of Filling Soil Tanks Heretofore a method frequently used for placing soil in experi- ment tanks has been to separate layers of soil as excavated from a trench and place them in the tank in the same order as originally found in the ground. This process broke up the soil structure, increased the volume, and changed the density. If tamped into the tank, alternate layers of loose and dense material resulted, with structural arrange- ments of soil particles entirely different' from the original. Soil mois- ture experiments with soil so placed have not always proved satisfac- tory. To rectify this condition the first tanks used in this investigation were filled without materially changing the original soil structure. The plan followed was to fill each tank by forcing the bottomless inner shell over a core of soil of the same diameter of the tank until full, at the same time excavating around the tank shell as the filling proceeded. At first use was made of a heavy screw jack resting upon a crib of timber blocks, which in turn rested upon the angle-iron rim, with the jack working against an overhead cable anchored in the ground on each side of the excavation. As the tank sank into the soil under the pressure, a gradually increasing pile of cribbing was used to support the jack against the cable. The anchors to which the cable was fas- tened were of a type generally used to anchor gaw wires and were set in auger holes bored in the ground. Friction of soil against the outside of the tank was relieved by excavating around the tank as the work proceeded. This excavation generally kept a few inches ahead of the cutting edge of the tank, cutting a core slightly larger than the tank diameter, the core being shaved to the proper size as the cutting edge of the tank moved doAvnward. As the tank gradually filled, the skin friction on the inside rapidly increased, tending to cause compression in the soil. After the first two or three attempts, it was found that the tank shell would slide over the trimmed core of soil more readily if a sharp blow was given at the to]) of the tank, using a short piece of timber as a driver. This impact broke the bond of the inside friction, resulting in less tendency toward soil compression and allowed increased speed in the work. A few of the last tanks to be filled were driven over the trimmed core of soil by impact alone. When the inner tank shell was filled, the soil column was cut off l)y jacking the bottom plate across the bottom edge of the tank and l)olting it to the angle-iron rim at the top. The whole was then hoisted above the ground by chain block and tripod. The outer shell was ther. set in place in the excavation, and the inner slu'U with its soil content 30 DIVISION OF WATER RESOURCES was lowered iuto the outer, where it hung suspended from the heavy iron rim around the top. As a means of comparing results of evaporation from similar soil placed in tanks by different methods, three tanks of the same size as those described were filled with loose soil taken from an excavation made to a depth of 6 feet. In making the excavation each foot of soil removed was kept separate from the others and placed in the tanks in the original order, foot bj^ foot. Before the tank was completely filled, it was flooded with water to compact and settle the material in a uniform manner. Water was added from time to time until it drained from the bottom through a pipe connection. Very little settlement occurred after the initial settlement and there is no doubt as to this method producing a more uniform soil density' than is obtained by placing and tamping the soil in layers. The Mariotte Tank This device consists essentially of a supply tank equipped on the principle of the Mariotte flask to supply water to the soil tank through a connecting pipe. A 12- by 36-inch galvanized-iron range boiler, chosen because of its solid construction, rigidity of its connections, and practicability of keeping it air-tight, was found satisfactory for the purpose. Mounted upon the side of the supply tank is a vertical length of glass tubing, each end of which is fitted with a rubber stopper perforated to admit a small connecting pipe. The lower pipe connects -svith the supply pipe between the Mariotte tank and the soil tank, while the upper connects with the top of the supply tank. Upon the glass tube is mounted a meter stick or scale upon which differences in daily readings determine the amount of water withdrawn. A valve in the connecting pipe makes it possible to shut off the flow of water when the supply tank is being refilled. A waste pipe also is set into the connecting pipe to discharge excess water from the soil tank into a receiving vessel. The lip of the waste pipe is set at the level of the water in the soil tank. The tank equipment is shown in Plate II. A vent tube of small diameter passes through the rubber stopper at the top of the glass gage. This tube is open at both ends and the level of the soil water is determined bj' the elevation of the bottom end of the vent. In Plate II, the water table in the soil tank is shown as being at such a depth that it is necessary to extend the vent tube downward into an extension well below the supply pipe. Previous experience has determined that A'ariations in temperature cause changes in the vapor pressure in the jMariotte tank above the water surface, causing fluctuations in the water level. Every effort was made, therefore, to insulate the IMariotte tanks against temperature changes. The Santa Ana ]\Iariotte tanks were completely buried in the ground except for a small entrance provided with a narrow door- way for making readings of the graduated scale. They were further protected from the cooling effect of rainfall on the surrounding soil by a galvanized iron roof, beneath which was free circulation of air. For the benefit of those who may be interested in the theory of operation of the Mariotte tank, a brief description follows. The vent tube provides the Mariotte control feature which maintains a constant water level in the connected soil tank. In operation, the Mariotte tank is filled -with water and the valve in the connecting pipe is opened. WATER LOSSES FROM WET AREAS 31 PLATE II .0-9 ^1^ I ! t--_- ni c i^*sii.r-^M^,£S^^j^ ^ VI ^ -, D- -^ — "5 ^ +- i- C 3 0) VI > . <0 E S o v> t: W " hA (-1 K < < ^ ^ 2 ^ 00 O O Z « 1-1 >-' < 0- IS < < K O « H o 2 < O (/) O Q H O [I) 2 2 O u 2 < U H O Pi < s 32 DIVISION OF WATER RESOURCES allowing' water to fiow to the soil tank. As the water level drops in the supply tank a partial vacuum is formed above the water surface and the water drops in the vent tube from the original level to a point depending- upon the degree of vacuum established. This point is determined by the ditference in the pressure heads, due to atmospheric pressure and the partial vacuum in the supply tank. Water will con- tinue to fall in the vent tube, but at a greater rate than in the Mariotte tank, until the pressure head corres])onding to the atmospheric pressure minus the pressure head caused by the partial vacuum is balanced by a column of water equal to the ditference in elevation between the water surface in the Mariotte tank and the bottom of the vent. Water will then stand in the vent at the bottom of the tube with the pressure at this point atmospheric. If the water continues to flow, air will enter the glass gage through the vent tube, bubbling upward through the water in the gage to enter the top of the supply tank. Water will continue to rise in the soil tank up to the level of the lower end of the vent, at which point the atmos- pheric pressure in the soil tank and the bottom of the vent tube is the same. As there is no ditference in pressure and both points are at the same level, there is no head to cause further flow and bubbling will cease. AVhen the water table in the soil falls below the bottom of the vent, the balance of pressures is again disturbed and a flow of water will again start from the Mariotte tank, replacing the amount used. Some of the difficulties in the accurate use of the Mariotte tank should not be overlooked. As the partial vacuum in the tank must be maintained at all times, pipe connections must be air-tight. Air leaks through the many joints in the system disturb the balance of pressure necessary for automatic control. Thorough insulation against tempera- ture changes inside the tank have been previously mentioned. Such changes cause expansion or contraction of the tank itself, of the water in the tank and also of the air in the chamber above the water. The combined result is to cause changes in the vapor pressure with a result- ing influence upon effective regulation. Water in the glass tube will fall with an increase in temperature in the Mariotte tank, and readings on the scale taken at this time will be erroneous. A test of the effect of temperature on scale readings showed that an increase of 30° F. in air temperature caused a fall of 1 cm. in the water surface in the glass gage. The temperature change inside the Mariotte tank during the test was not measured. When the temperature returned to the starting point the water in the gage returned to its original position. If the gage readings are taken at an early morning hour each day, the difference in the readings will repre- sent a true rate of loss as early morning temperature changes are too small to affect vapor pressure. Eeadings taken at other times of the day may be in error unless complete insulation of the supply tank is effected. SAN BERNARDINO STATION Description of Site In choosing a site for tank experiments in the upper Santa Ana River Valley, a small plot on the grounds of the Antil Pumping Plant of the San Bernardino Water Department,* about 1 mile east of town, * The Municipal Water Department of the City of San Bernardino, tlirougli tlie courtesy of William Starke, as.sisted in maintaining this station. WATER LOSSES FROM WET AREAS 33 was selected after a stiidj^ of soil and ground-water conditions in the vicinity. The plot lies in a level field of Bermuda grass, at some dis- tance from any buildings, and has excellent exposure. Climatic conditions at this point are representative of the interior climate of southern California, and summers are hot and dry. Winter temperatures are lower than at the Santa Ana station, and rainfall is greater. Soil used in the experiment tanks was taken in place at the station site and is classified as Chino silt loam.* Although the location of the station is in an area of high ground water, no evidence of alkali appeared on the tank surfaces during the 3 years of operation. Fluc- PLATE III f •.•^%r..- ,% BOARD HOUSING FOR MARIOTTE TANKS AT SAN BERNARDINO. tuations of ground water level, varying from 2^ to 6 feet from the sur- face, occur each year, being lowest during the summer months. The station is supplied with artesian w^ater from the city pumps. Station Equipment Tank equipment at the San Bernardino station is similar to that at Santa Ana, although not the same in number of tanks. Four soil tanks, each 23^^ inches in diameter, were set with their tops level with the ground surface. Because of existing high ground water, these are 40 inches in depth instead of 6 feet. Each tank is connected with a ]\rariotte supply tank to furnish water to the soil tank as needed and to maintain a constant water level in the soil. * Soil Survey of the Riverside Area, California. Bureau of Soils, U. S. Depart- ment of Agriculture. 3 — 4503 34 DIVISION OF WATER RESOURCES Because of ground water conditions, it was not deemed advisable to set the Mariotte tanks under<;round for protection from temperature changes as at Santa Ana. Instead, each tank was placed above ground enclosed in a white painted board shelter. This is shown in Plate III. Each shelter box has a narrow doorway opening before the glass gage and a hinged top to allow access for refilling the tank when empty. To provide insulation against temperature changes as much as possible, the space between the tank and the sides of the box are filled with wood shavings and the tank is wrapped with asbestos paper. Evaporation was measured from a standard Weather Bureau pan mounted on a timber grill and from a ground tank 23iV inches in diameter by 2.7 feet in depth. This tank was set mth the rim 3 inches above the ground surface and the water surface was held near the ground level. All eva])oration readings were obtained with a hook gage equipped with a vernier reading to thousandths of a foot. A four-cup anemometer was mounted on the platform of the pan, with the cups about 12 inches above the top of the pan. A single tank, 23iV inches in diameter by 2.7 feet in depth, was used in which consumptive use of water by round stem tules in sub- merged soil was measured. It was set in the ground with about 3 inclies of the rim exposed and connected to a supply tank through a float arrangement, previously described. A glass gage and a graduated scale mounted on the side of the supply tank allowed measurements of water withdrawn for plant use. Additional equipment consisted of maximum and minimum tlier- mometers housed in a standard shelter and an 8-iuch rain, gage: PRADO STATION Description of Site A small station was established near Prado on the Santa Ana River, midway between Santa Ana and San Bernardino, during the sunnner of 1930, for collection of meteorological records, measurement of evapo- ration from a water surface, and consumptive use of water by trian- gular stem tules. The site is on slightly sloping ground near the lower end of the Prado basin and is fully exposed to sun and wind. The climate is intermediate between the interior climate at the San Bernardino station and the coastal climate at Santa Ana, as it is tempered by the ocean breezes blowing through the Santa Ana canyon into the Prado basin. This station Avas operated in cooperation with the U. S. Geological Survey. Station Equipment The Prado station is equipped with a standard Weather Bureau evaporation pan, a ground tank growing tules for measurement of consumptive use of water, a thermograph housed in a standard shelter, a rain gage, and an anemometer. The evaporation pan and the tule tank are each equipped with a supply tank connection operating through a float valve arrangement to supply and maintain a constant water level in the pan or the tank. T'^se of water in each case is meas- ured on the chart of a w^ater stage recorder mounted with a float in the supply tank. This arrangement operates satisfactorily, the hourly rate of use being computed from the chart. A barograph also is used WATER LOSSES FROM WET AREAS 35 at iutervals. The station is protected from intrusion by a high wire fence with a gate, which is kept locked. METEOROLOGICAL RECORDS The three experiment stations just described are spaced at nearly equal intervals of about 25 miles along the Santa Ana River. While the distances between the stations are not great, the topography of the area is such as to cause material differences in climate. The Santa Ana River Valley is divided into two distinct basins, known as the upper and lower, connected by the lower Santa Ana canyon. The Santa Ana station lies on the coastal plain of Orange County below the canyon and has a distinctly coastal climate characterized by ocean breezes and light summer fogs, both of which modify the summer tem- peratures. The Prado station, in Prado basin, Riverside County, is in the lower part of the upper basin at the upper end of the canyon. It is slightly remote from the coast but not far enough away to be removed entirely beyond the effect of the coastal breeze. The principal difference is the absence of coastal fog, with some increase in tempera- ture. The San Bernardino station, San Bernardino County, in the upper basin, is removed farther from the effect of ocean modifying influences. The climate is classed as interior and the temperature is higher in summer than at either of the other two stations. The prevailing winds are from the southwest, off the ocean, and pass through the Santa Ana canyon by the Prado station. The total yearly wind movements here and at Santa Ana are about equal, but during the summer months the greatest movement occurs at Prado. This condition combined M'ith higher summer temperature results in a higher rate of evaporation than at the other stations. Rainfall is deficient throughout the whole of the Santa Ana River basin except in the higher mountain districts, and occurs almost entirely between November and April, inclusive. Other months are almost devoid of precipitation. Meteorological data for the three stations for the period of the investigation, showing monthly mean maximum, mean minimum and mean temperatures, rainfall, and wind movement in miles per month are given in Tables 1 to 3, inclusive. Rainfall at Santa Ana and San Bernardino is shown for storm periods in Tables 4 and 5. 36 DIVISION OF WATER RESOURCES TABLE 1 MONTHLY TEMPERATURES, RAINFALL, AND MILES OF WIND MOVEMENT AT SANTA ANA STATION Temperature, degrees Fahrenheit Rainfall in inches Wind Month Mean maximum Mean minimum Mean Maxi- mum Mini- mum movement in miles 1929— 74 76 81 85 79 80 77 72 62 66 68 72 70 75 81 82 77 80 77 70 68 68 76 76 77 81 85 84 84 79 68 63 61 62 69 72 51 53 60 60 58 52 41 41 40 44 46 47 48 55 57 59 54 47 43 36 40 45 42 49 56 56 64 62 55 50 42 37 37 40 41 42 63 65 71 73 69 66 59 57 51 55 57 60 58 65 69 71 66 64 60 53 54 57 69 63 67 69 75 73 70 65 55 50 49 51 55 57 91 95 89 96 98 101 91 86 76 87 89 88 83 88 95 93 90 95 95 82 85 75 92 88 92 99 94 96 97 97 83 73 77 87 87 89 41 43 52 51 42 36 33 30 30 33 33 39 40 47 48 51 48 39 30 24 30 49 33 41 50 49 57 56 43 39 28 30 30 29 33 35 0.03 .11 July .35 1,695 October - - 1,745 November - 1,806 1,547 1930— Januarv 5,55 .55 2.99 .80 1.23 .02 1,743 1,682 2,212 April - 1,970 May 2,228 June 1,871 July 1,671 Aiiffust - 1,518 Sentember - .02 .07 1.47 1,381 1,322 1,534 December - _ _ _ - 1,389 1931- Januarv 3.82 2.28 .03 2.68 ,67 .07 1,382 1,378 March - 1,830 1,736 1,781 1,670 July 1,656 .43 .29 .09 1.69 4.70 2.04 4.53 --- 1,415 1,201 1,121 November - - - - 1,223 December - 1,136 1932— January 1,335 February ._ 1,371 1,510 1,659 WATER LOSSES FROM WET AREAS 37 TABLE 2 MONTHLY TEMPERATURES, RAINFALL AND MILES OF WIND MOVEMENT AT PRADO STATION Temperature, degrees Fahrenheit Rainfall in inches Wind Month Mean maximum Mean minimum Mean Maxi- mum Mini- mum movement in miles 1930— June 81 92 90 82 82 77 49 52 55 50 41 39 65 72 73 66 62 58 102 106 100 103 101 98 40 42 47 41 28 25 July 2,034 August 6"27" 1.43 1 858 September 1,540 October 1,232 1,438 1,950 November _ - December 1931— January -, . _ 2.47 3.53 .09 2.17 .55 1,738 979 Febmarv March 1,373 1,646 May - - 80 85 94 93 89 81 69 52 53 63 61 52 49 37 66 69 79 77 71 65 53 94 100 105 106 102 95 93 43 46 53 53 41 39 23 1970 June 1,840 July. 2,240 .16 .15 1.89 2.69 4.77 2.29 5.29 .12 .82 1,922 Septemb-er 1,496 1,249 1,257 1,223 1,679 October - __ __ November . 1932— January' .. . - February _ _ 1,217 1,512 April - 1,313 Mav 2,116 June - ._ 82 85 88 84 79 83 65 50 54 54 54 47 39 34 66 70 71 69 63 61 50 102 92 102 98 92 93 85 43 45 44 49 32 29 27 2,285 July - 2,418 August 2,304 1,892 October . .- .- .73 1,743 1,398 December 1,578 38 DIVISION OF WATER RESOURCES TABLE 3 MONTHLY TEMPERATURES, RAINFALL AND MILES OF WIND MOVEMENT AT SAN BERNARDINO STATION Month 1929- May June July August September- October November- December.. 1930— January February.-. March April May.. June -- July August September. October November. December. . 1931— January February... March April May June July August September - October November- December- - 1932— January February... March April Temperature, degrees Fahrenheit Mean Mean maximum mmimum 82 47 88 50 95 57 98 60 88 55 85 46 80 34 75 33 61 36 74 38 70 41 77 45 74 43 86 52 96 54 95 57 84 50 82 44 77 39 72 27 68 35 66 40 76 37 79 44 83 52 86 53 98 62 95 61 89 51 81 47 69 37 Mean 65 69 76 79 72 66 57 54 49 56 56 61 59 69 75 76 67 63 58 50 52 53 57 62 08 70 80 78 70 64 53 Maxi- mum 94 108 106 106 107 98 91 85 76 87 88 95 95 101 106 104 102 94 90 79 82 73 92 94 95 101 107 108 99 100 93 Mini- mum 37 39 49 51 41 31 26 25 24 31 28 35 34 42 43 50 42 34 28 19 25 30 24 35 42 46 53 51 40 37 23 Rainfall in inches 0.12 .53 4.71 1.06 3.99 1.33 1.76 1.24 2.08 2.15 3.73 .60 2.73 .89 .06 "i"57 .24 1.14 3.17 3.59 2.61 5.99 .20 .72 Wind movement in miles 1,012 1,183 1,589 1,255 1,434 1,357 1,864 1,143 947 900 679 879 895 1,086 1,257 748 798 890 816 797 1,177 1,013 902 1,168 1,391 1,391 WATER LOSSES FROM WET AREAS 39 TABLE 4 RAINFALL BY STORMS AT SANTA ANA STATION 1929-30 1930-31 1931-32 Storm period Rainfall in inches Storm period Rainfall in inches Storm period Rainfall in inches 1930— .Tan 5-6 0.80 4.27 .48 .45 .10 .41 2.51 .07 .80 1.19 .02 .02 .02 .02 1930— Oct. 8-9 0.07 .65 .82 .40 2.49 .10 .03 .80 1.82 .04 .01 .41 .03 2.68 .67 .05 .02 .02 .41 .02 .04 .23 1931- Oct. 1 0.01 Jan 9-19 Nov. 13-17 Oct. 8 .02 Jan 26-27 Nov. 26-29 Oct. 17-19 .06 Feb ''0-22 1931— Nov. 1-2 .03 Feb 26-27 Nov. 7-11 .20 Mar 3-5 Nov. 14-15--- .83 Mar. 13-18 Jan. 5-8 Nov. 26-27 .63 Mir ''9 Jan. 13 Dec. 8 1.49 Anril ''9-30 Jan. 23 Dec. 10-11 .16 May 1-4 Jan. 30-31 Dec. 14 .50 May 8 Feb. 3-4 Dec. 20-25 .87 ^Iay 16 Feb. 6 Dec. 29-31 1.68 June 20 Feb. 8 1932— Jan. 1-3 - - Sept. 30 Feb. 10-12 Mar. 11 .23 April 21-27 Jan. 12-15 .78 May 24-25 Jan. 26- .03 Jiine 4—5 Jan. 31 - 1.00 June 25 Feb. 1-9 3.26 Aug. 12 - - Feb. 13-18 April 24-26 1.27 Aug. 28 .35 Sept. 2-3 Sept. 24-25 Sept. 30 . Totals, October 1 to September 30 11.16 11.81 13.40 TABLE 5 RAINFALL BY STORMS AT SAN BERNARDINO STATION 1929-30 1930-31 1931-32 Storm period Rainfall in inches Storm period Rainfall in inches Storm period Rainfall in inches 1930— •Jan. 5-14 4.23 .48 1.06 .48 2.39 1.12 .02 1.31 1.54 .11 .11 1930— Oct. 8-10 1.24 1.45 .63 .83 .33 .69 .30 .35 2.28 .05 .67 .38 .60 2.73 .89 .06 .36 1.21 .09 .09 .06 1931— Oct. 1 0.13 Jan. 26-27 Nov. 13-17 Oct. 18 1.01 Feb. 19-26 Nov. 26-27 Nov. 7 .02 Mar. 4-5 1931— Jan. 1-2 Nov. 10-11 .16 Mar. 14-16 Nov. 14-15 -- 1.35 Mar. 30-31 Nov. 19 .25 April 13-14 Nov. 26-27 .99 \pri! 28-30 Jan. 7-8 Nov. 30 .40 .May 1-4 Jan. 31 Dec. 8 1.02 May 8 Feb. 1 - Dec. 10-11 .42 May 17-18 Feb. 4-6 Dec. 14 .23 Feb. 8.. Dec. 20-21 .21 Feb. 11-15 Dec. 25.. .36 Feb. 19 Dec. 27-28 1.35 Mar. 24 . 1932— April 22-29 May 25-26 .34 June 5 Jan. 12-13 .40 Aug. 10-11 Jan. 15 .49 Aug. 28-29 Jan. 26 -.. .06 Sept. 2 Jan. 31 . 1.32 Sept. 25 -•-. Feb. 1 .53 Sept. 30 Feb. 6-9 2.95 Feb. 13-18 2.47 Feb. 29 . .04 Mar. 2 .01 Mar. 14.. .19 April 24-27 .72 Totals, October 1 to September 30 12.85 15.29 17.42 40 DIVISION OF WATER RESOURCES OPERATION OF TANKS Sources of Errors in Tank Experiments In conducting investigations of the consumptive use of water by- plant life two methods, each of which has certain advantages when used under the proper conditions, are available to the investigator. These are as follows : 1. Determination of consumptive use by field-grown crops by- studying soil samples taken with a soil tube. 2. Quantitative measurements of consumptive use by crops grown in tanks. Both methods have been used since studies were first begun in this field, but as knowledge of the subject increased there have been improve- ments in both method and equipment. The practice of taking field soil samples at various depths by means of the soil tube for determina- tion of soil moisture is applicable to practically all conditions of soil and crop, and consumptive use of water data may be derived from results so obtained. Similar results may be obtained by measurement of water applied to crops grown in tanks. On account of limitations in the size of tanks that may be used in experimental work, such experi- ments generally include only field or other crops having limited root systems. Previous investigators have approved the tank method of studying consumptive use of Avater, though it is subject to some errors which must be overcome as far as possible to secure applicable results. Hence, it is necessary to have some knowledge of the various sources of error. The factors influencing transpiration determinations with rooted plants in tanks as sources of experimental errors have been outlined by Kiesselbach* as follows : 1. Character of potometer and contents. a. Limitation of amount of soil. 1. Througli size of potometer. 2. Through number of plants grown in potometer. b. Limitation of fertility of soil. c. Improper distribution of soil moisture. d. Evaporation from surface of soil. e. Entrance of rain water. f. Exposure of potometer and consequent effect on soil temperature. g. Unintentional lack of uniformity in soil. 2. Environment. a. Testing under unnatural habitat. 3. The plant. a. Plant individuality. 1. Insuflicient number of replications. 2. Disease and injury. b. Stage of maturity. 1. Insufficient development. 4. Errors due to methods of computation. 5. The personal element in drawing conclusions. These factors apply also to transpiration plus soil evaporation, which is termed consumptive use of water or sometimes use of water. In the investigation reported herein a number of these sources of error were anticipated and efforts were made to minimize them b}' the selec- tion of tanks of sufficient size to provide soil capacity for proper growth of the types of vegetation chosen for study, by the method of filling the tanks with undisturbed soil and by protection from exposure to * Transpiration as a Factor in Crop I'roduction, Nebraska Agricultural Experi- ment Station Research Bulletin No. U, by T. A. Kiesselbach. 1916, WATICR LOSSES FROi\[ WET AREAS 41 diurnal changes of temperature by setting all tanks in the ground with tlie tops level with the ground surface. The growth in any tank should not exceed the number of plants of the same crop ordinarilj^ grown in an equal area under normal field conditions. Not only should the area per plant be maintained but also the volume of soil available for plant roots is important. In tanks having high water tables the soil volume is sometimes limited, curtailing growth of the root system and likewise affecting the aerial growth. jMoreover, a small volume of available soil will soon lose its fertility if heavily cropped. This is especially true of anj^ investigation extending over, more than one crop year when the soil in the tank is unchanged. A sufficient lack of soil fertility may result in a higher water requirement per unit of drv matter produced and be the cause of a considerable source of error. A further error also exists when the spread of area of foliage grown in a tank exceeds the tank area. Cases of this kind are found when the groAvth droops or spreads beyond the tank limits. In such a case computation of consumptive use per unit of tank area gives an amount in excess of the true consumptive use as the crop area is in excess of the tank area. Experimental records of consumptive use of water by plant growth in tanks include evaporation from the soil as well as water transpired through the stomata of the plant leaf. To the agriculturist and others interested in determining the amount of irrigation water which should be applied to soil in order to produce a normal crop, a separation of the water losses into evaporation and transpiration is not important and the water requirement of a crop as determined by experiment generally includes both soil evaporation and plant transpiration. In making such experiments, evaporation and transpiration can not readily be separated from each other except through the use of methods that are inapplicable to field conditions. Evaporation from soil tanks having the same climatic exposure varies with the degree of soil satura- tion, soil texture, and crop shading. In the tanks used in the experi- ments described herein both the degree of crop shading and the soil moisture at the tank surface varied greatly. Both are greatest for those tanks having the highest water tables. It is evident, therefore, that it is not proper to subtract soil evaporation from consumptive use of water by the crop to arrive at the transpiration alone. Lack of natural euAdronment is also an important source of error in conducting consumptive use of water studies by the tank method. As transpiration and evaporation are closely related to climatic condi- tions, tank experiments with crops nuist be conducted where the experi- mental growths can be maintained in their natural environment. Experiments with field crops should be carried on in fields of the same crop variety, those with grasses should be in meadows where the same kind of grass has a natural growth and experiments with swamp growth must be conducted in a swamp area where humidity is high, to obtain results that are at all comjiarable with actual swamp con- sumptive use. Santa Ana Station Because of errors which might occur in the use of water by evapora- tion or consumptive use of water by crops in different soil tanks, it was thought best to operate all tanks in sets of three, the depth to water 42 DIVISION OF WATER RESOURCES level and variety and age of crop being identical in each. Twelve tanks were filled with undisturbed soil and three with loose soil settled in svater. Complete installation data on tanks in ^^se at the Santa Ana station, giving the diameter, the use made, period covered by test, content, and depth to water table are shown for each tank in Table 6. TABLE 6 INSTALLATION DATA ON TANKS USED AT SANTA ANA STATION Tank number' 1-2-3 1-2-3 1-2-3 4-5-6 4-5-6 7-8-9 7-8-9.---- 10-11-12.. 10-11-12-- 13-14-15.. 13-14-15.- 16 17» 18" 19 20 21 22 23 24 25 26 Dia Beter of tank in inches 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 25 1/2 48 25 1/2 25 1/2 72 72 25 1/2 48 Purpose of tank Evaporation . Evaporation . Use of water - Evaporation _ Use of water - Use of water - Use of water. Use of water - Use of water - Evaporation - Use of water - Evaporation - Evaporation . Evaporation - Use of water. Evaporation - Use of water - Use of water - Use of water - Use of water . Use of water. Evaporation . Period of test Beginning May, 1929 Oct., 1929 Oct., 1930 May, 1929 Oct., 1930 May, 1929 Oct., 1930 May, 1929 Oct., 1930 July, 1929 Oct., 1930 May, 1929 .A.ug., 1929 \ug., 1929 Aug., 1929 Mav, 1929 Mav, 1930 May, 1930 May, 1930 Mav, 1930 Aug., 1930 May, 1931 Ending Oct., 1929 Oct., 1930 April, 1932 Oct., 1930 .\pril, 1932 Oct., 1930 April, 1932 Oct., 1930 April, 1932 Oct.. 1930 April. 1932 April, 1932 Mav, 1930 May, 1930 April, 1932 April, 1932 .April, 1932 .April, 1932 April, 1932 April, 1932 April, 1932 April, 1932 Content of tank Bare soil Bare soil Salt grass Bare soil Salt grass Salt grass Salt grass -- Salt grass Salt grass Bare soil Salt grass Free water surface Water covered with oil film Water covered with oil film Round stem tules in water Free water surface Triangular stem tules in water Cat-tails in water Round stem tules in water Willow Wire rush Five per cent sodium chloride solution. Depth to water table in feet ' Undisturbed soil was used in Tanks Nos. 1 to 12, inclusive; disturbed soil in Tanks Nos. 13, 14, and 15. 2 Results of these experiments are published in State of California. Department of Public Works Bulletin No. 33. When the station was first installed, in 1929, four tanks had an original growth of salt grass growing on the column of soil enclosed in them, two others had salt grass transplanted in them, and the rest had bare surfaces. Use of water by salt grass and evaporation from bare, uncultivated soil was measured from these tanks from May, 1929, to October, 1930, when several changes in water levels were made and all bare-soil tanks had salt grass transplanted in them. The new grass did not make good growth at first, and until gro^\•th began in the following spring the recorded use of water was largely due to soil evaporation rather than to consumptive use by the transplanted gi'ass. No further changes were made in the crop grown or in the depth to water table in any soil tank after the changes noted in October, 1930. For reasons which will be given later, measurements of evaporation from bare, uncultivated soil surfaces in Tanks Nos. 1, 2, and 3 were begun with an initial water table depth of 4 feet and were continued thus throughout the summer of 1929. It soon became evident that this water-table depth was greater than the limit of capillary rise of the soil moisture. This was evidenced in part by the lack of soil moisture in surface soil and proved beyond doubt by the fact that there was no withdrawal of water from the Mariotte supply tanks during a five- month period which included tlie warmest months of the year. In October following the period during which no evaporation occurred the water-table levels were raised from 4 to 3 feet from the WATER LOSSES FROM WET AREAS 43 surface and the evaporation test was continued. There was immediate response in loss of water from tlie supply tanks, but indications were that the large initial losses from the JMariotte tank were partly absorbed by the dry soil as capillary moisture, and that only a small part was lost by soil evaporation. This adjustment of soil moisture continued for a period of four to six weeks until the capillary demand was satis- fied, after which a small but rather uniform rate of evaporation con- tinued. The evaporation test with water tables at a 3-foot level continued for the following 12-month period to October, 1930, at which time a number of changes in depth to water tables in some tanks were made and all soil evaporation tanks were transplanted to salt grass. It was rather hard to get this started and in some cases light surface irriga- tions were applied as the tank surfaces were generally quite dry. Moreover, the time of year was not the best for starting new growth and the grass was slow in developing a root system. Consequently the recorded use of water during the winter or dormant season by those tanks in which grass was newly transplanted was almost entirely caused by evaporation from the soil surface rather than l)y consumptive use. The increase in use of water beginning in jNIarch, foUoAving trans- planting, shows definitely that this was the end of the dormant period for the salt grass in this set of tanks. The second set of tanks, Nos. 4, 5, and 6, containing undisturbed soil, were first used for measurement of evaporation from the soil surface with the water table at a depth of 2 feet. As this depth was well within the limit of capillary rise, evaporation began immediately after the soil received water and continued until October, 1930, when the soil evaporation tests were completed. The first two months of record in 1929 showed a high rate of loss from the iMariotte supply tank, which may be accounted for as ad.justment and increase of moisture held in the soil following establishment of a fixed water table. Such losses were observed in every case where the water table was raised to a higher level. Immediately following completion of the evaporation test, the tanks in this set were transplanted to salt grass, the water table remaining unchanged. As with the first set of tanks, the grass was slow to start and some early surface irrigation was necessar}^ Consequently, the water used during the following winter when the grass was in the dor- mant stage was almost entirely soil evaporation. Increase in growth began in the following February and these tanks were soon covered with a luxuriant growth of grass which completely shaded their soil surfaces. Kecords were made until April 30, 1932, when the investi- gation was completed. The third set, including Tanks Nos. 7, 8, and 9, was first operated with a 2-foot water table, but with salt grass sod instead of bare sur- faces. Tank No. 9 was the only one to have an original crop of grass at the outset. In this tank the grass root system was fully developed and remained undisturbed, exceept where the shell of the tank cut off lateral roots as it was forced into the ground. The other two tanks were bare, and it was necessary to transplant grass and tlevelop root systems before the maximum use of water was attained. The trans- planted grass showed a very heavy and healthy growth of 6 inches or 44 DIVISION OF WATER RESOURCES more. Tank No. 9. on the other hand, had a heavy mat of short stemmed grass which did not compare in height with the new growth. Records were kept of the consumptive nse of water nnder these conditions from j\Ia.y, 1929, to October, 1930, when the water table was raised from 2 feet to 1 foot, remaining at this level until the end of the investigation. From the very beginiiing, these tanks had moist soil surfaces on which accumulations of powdery alkali occurred, and with the rise in the water table, this became more pronounced. The concentration, however, was not sufficient to cause injury to the salt grass, which increased in height and density with the higher water table. Tanks Xos. 10, 11, and 12, comprising the fourth set, were covered with the original salt grass sod found growing on the surface when the tanks Avere filled, and therefore had fully developed root systems from the beginning. Prom the first this groAvth was very dry and sparse and did not increase in density when additional water was sup- plied. The initial water table was at a depth of 4 feet and consump- tive use of water measurements were made under these conditions from May, 1929. to October, 1930, when the water table was lowered to 5 feet. At this depth the experiment was continued until the investiga- tion was completed. As the water table was always below the limit of capillary rise, the tank surfaces remained dry in contrast with others which were always moist. In consequence, there was little or no soil evaporation and no surface deposit of alkali. Tanks Nos. 13, 14, and 15 were installed during the summer of 1929, for the purpose of comparing evaporation from soil in tanks filled by different methods. The comparisons were to be with Tanks Nos. 4, 5, and 6, ]n-eviously described. Each set had the same depth to water, the same bare surfaces, and contained the same type of soil, except that Tanks Nos. 4, 5, and 6 contained undisturbed soil, while Nos. 13, 14, and 15 were loosely tilled. These comparisons of evaporation from soils of different structural arrangement were continued until October, 1930. At this time the soil evaporation studies were discontinued and all bare tanks were transplanted to salt grass for further comparative studies. After both sets of tanks were transplanted to salt grass, the comparison was con- tinued without changes in depth of water tables until the investigation was discontinued. Both sets of tanks produced good growths of grass, although that grown in the loose soil was not as heavy as that grown in the undisturbed soil. In addition to use of soil tanks with ^Nlariotte connections for evaporation and consumptive use of water studies, several tanks of simple design were used for growths of tules, willows, and wire rush. As tules are aquatic plants accustomed to grow in swamps with their roots submerged, the tanks in which they were grown were maintained with water tables about 2 inches above the soil level. The height of the water table was determined by an index point in each tank. In the smaller tanks the water table was raised to the index point each morning by using a measured anu)unt of water. In larger tanks this involved a greater amount of work and supply tanks were operated to maintain llic proper water level and supply water as used. In the WATER LOSSES FROM WET AREAS 45 willow and wire rush tanks, the water table was kept 2 feet below the soil surface with sliglit fluctuations. San Bernardino Station The four tanks used at the Antil Plant of the San Bernardino Water Department were installed for measurement of consumptive use of water by Bermuda grass, of which there was a heavy crop growing in the yard in which the tanks were set. As the tanks were filled with undisturbed soil each had a good stand of grass with root systems fully developed from the beginning of the investigation. At this station tanks were operated in duplicate, one pair having a depth of water table of 3 feet and the other of 2 feet below the soil surface. These depths were unchanged throughout the investigation. Each soil tank was connected to a ^Nlariotte supply tank from which the daily amounts of water used were measured. Besides the four soil tanks, one tank of round stem tules was maintained to determine the consumptive use by this growth. This tule tank was coimected with a supply tank through a float valve to supply water as needed and hold the water table at an index point about 2 inches above the soil level. Installation data giving the number of tanks, periods of use, and content of each tank are shown in Table 7. TABLE 7 INSTALLATION DATA FOR TANKS USED AT SAN BERNARDINO STATION Tank number' 1-2 3-4 5-- 6- 7-- Diameter of tank in inches 23 1,16 23 1/16 23 1/16 23 1/16 4S Purpose of tank Use of water. Use of water. Evaporation . Use of water. Evaporation _ Period of test Beginning Ending May, 1929 May, 1929 Mav, 1929 April, 1930 May, 1929 Jan., 1932 Jan., 1932 April, 1932 April, 1932 April, 1932 Content of tank Bermuda grass Bermuda grass Free water surface Round stem tules in water. Free water surface Depth to water table in feet ' Undisturbed Chino silt loam soil used in Bermuda grass tanks. Prado Station* Only one crop tank has been used at the Prado station in deter- mination of consumptive use of water. This tank contains a dense growth of triangular stem tules grown in submerged soil as at the other stations. A supply tank is used in connection with the tule tank, the connection being made through a float valve. Measurement of water withdrawn from the suppl}' tank is shown on recorder charts by means of a water stage recorder, and weekly or semiweekly visits are made to the station to replenish the water supply and renew the charts. This station is still in operation and will be continued. Protection from Rainfall During the wet seasons of 1929-30 and 1930-31, covers were pro- vided for all soil tanks to prevent changes in soil moisture content due to rainfall. The covers (Plate IV) were of light metal, circular in design and ^\■^th sloping tops, and Avere set on legs a few inches high to allow full circulation of air over the protected tank surface. While it was impossible to keep all rainfall from the tanks be(!ause of absence from the station at the exact beginning of each storm, they were set as * Thf United States Geological Survey, cooperated in maintaining this station through the courtesy of F. C. Ebert. 46 DIVISION OF WATER RESOURCES soon as possible and removed when the rain ceased. The amount of addi- tional moisture the tanks received from rainfall Avas negligible and was soon evaporated. There is objection to using covers as the shade they give reduces both evaporation and transpiration. At the time they w'ere used, however, both evaporation and transpiration were at a minimum on account of overcast sky and increased humidity. Also, because covers were raised above the soil tanks by the legs on which they stood, normal air movements were not restricted. Beginning with the 1931-32 rainy season, it was decided to have all soil tanks exposed to rainfall and covers were not used as during PLATE IV CIRCULAR METAL COVERS TO PROTECT SOIL TANKS FROM RAINFALL WHILE ALLOWING FREE CIRCULATION OF AIR OVER THE TANK SURFACE. the two previous seasons. Under these conditions each rain changed the water content of the soil. The additional soil moisture was dis- posed of by evaporation and transpiration or the excess drained off through the overflow outlet to be caught and mea,sured in a container. On account of changes in soil moisture, withdrawals of water from the Mariotte tanks did not give a correct index of consumptive use by the soil tanks. Recourse to taking soil moisture samples from each tank at the beginning of each month was therefore necessary. Consumptive use was computed as the algebraic sum of the change in soil moisture, rainfall during the period, water drawn from the supply tank, and waste water measured in the overflow containers. Certain inaccuracies inherent to this method could not be avoided. Probably the most important of these was caused by inability to obtain soil moisture samples immediately above the water table in the soil tank. This soil was saturated to such an extent that it could not be held in the soil tube, and the samples obtained indicated less moisture than actually existed. WATER LOSSES FRO^I WET AREAS 47 Since tanks were protected from rainfall durini>' the first two years and exposed dnrinti- the third year, results from tank studies are not entirely comparable. Greater evaporation occurred from tanks subject to rainfall, both from the soil surface and from moisture intercepted by the grass. On a heavy growth of grass, the latter item might be considerable during an entire season. There was every reason to sup- pose that consumptive use of water by crops grown in tanks exposed ro rainfall during the wet season would exceed that used in tanks protected from rain, and the records show this to be true. SOIL ALKALI IN TANKS Most western soils contain alkali salts in various amounts and the soil at the Santa Ana station was no exception. As the station was pri- marily for the investigation of consumptive use of water by salt grass, which is tolerant of a considerable concentration of salts, no eifect on the rate of transpiration was expected. Several tanks w'ere used for soil evaporation studies, and it is probable that in a few of these gradual deposition of alkali on the tank surface had some influence in reducing the amount of evaporation. The greatest evaporation from any tanks occurred from those holding disturbed soil, although the most alkali was evident on their surfaces. As the processes of evaporation and transpiration continued month after month, the original amount of alkali in the soil was increased by constant addition of water to the soil tanks. This water was obtained at the station from a shallow Avell and chemical analysis showed it to be relatively free from injurious salts and in every waj' suitable for tank use. Water used in the experimental work at the San Bernardino station was supplied from an artesian well and was even better for the purpose than that at Santa Ana. Samples of water from the annular spaces of a number of tanks at both stations also were analyzed and the results of both anatyses are shown in parts per million in Table 8. The carbonates are entirely lacking in both water supplies and bicarbonates and sulphates are the principal salts. No accumula- tion of salts is sho-\ra in the water of the annular space as they are carried into the soil for distribution. Apparently water used at the Santa Ana station is fair and the San Bernardino supply is good for irrigation. TABLE 8 ANALYSES OF STATION WATER SUPPLIES AND WATER FROM ANNULAR SPACES OF SOIL MOISTURE TANKS AT SANTA ANA AND SAN BERNARDINO STATIONS' Source of sample Classification of salts in parts per million Station 01 CO, HCO, SO, Ca Mg Na Santa Ana . Shallow well Shallow well Tank No. 2 Tank No. 5. Tank No. 8 Tank No. 11. - Tank No. 14 Artesian well. Tank No. 2 Tank No. 4 55 57 130 62 36 41 61 19 17 25 0 0 0 18 27 21 30 0 0 0 220 317 88 73 70 137 140 156 152 178 100 98 170 66 55 53 95 42 57 33 78 81 54 18 18 20 24 38 40 38 40 27 37 12 10 10 15 30 38 36 25 Santa Ana 76 Santa Ana 70 Santa .\na 75 Santa -\na _ - 75 Santa .\na . 85 Santa Ana.- 117 Sar Bernardino 10 San Bernardino San Bernardino -- 0 0 ' Samples for analysis were collected during October, 1930, except the second well sample at Santa Ana which was taken in January, 1932. 48 DIVISION OF WATER RESOURCES The migration of alkali salts through the soil, either upward or downward, is dependent upon the movement of soil water, in both direc- tion and amount. In the presence of a water table within the reach of capillary action, this movement ordinarih' is upward and when there is high evaporation there is a rapid concentration of salts at or near the surface. If the movement of salts was always in one direction, many fields would soon be ruined for production of crops. Fortunately, heavy rains and the surface application of irrigation water tend to carry the salts downward. In the soil tanks at Santa Ana, soil alkali accumulated during the dry season on the surface of those tanks having high water tables. In some cases white deposits were noticeable. During the wet season of 1931-32, these deposits were carried downward into the soil by penetra- tion of rainfall, and as the tanks were dismantled in May. 1932, much of the alkali had little opportunity to return to the surface. Exceptions occurred in Tanks Xos. 7, 8, and 9, in which the water tables were but 1 foot from the surface and a high concentration of salts was redeposited TABLE 9 ALKALI SALT CONCENTRATIONS AND pH VALUES OF COMPOSITE SOIL SAMPLES FROM VARIOUS DEPTHS IN SOIL MOISTURE TANKS AT THE SANTA ANA AND SAN BERNARDINO STATIONS- ' Samples for analysis were collected during June, 1932. WATER LOSSES FRO:\[ WET AREAS 49 iu the top inch of soil. About two months after the last heavy rain in the spring of 1932, samples of horizontal sections of soil in various tanks Avere collected for chemical analysis. The results of these analyses are shown in Table 9. The salts shoAm are predominately sodium salts, and extracts from the high carbonate soils were all black, indicat- ing black alkali. There was no calcium present in the solution, due to the high content of the carbonate ion. Also, the amount of sulphates present is of no importance. The pH values at the Santa Aiia station are very high, ranging from 8.4 to 10.6. These values indicate a highly alkaline reaction. In the tanks of undisturbed soil where depth to water table was 2, 3, or 5 feet, the surface concentration of salts in the top inch of soil was not excessive. With a water table 1 foot from the surface, there was an extremely heavy deposit of salts in the top inch, measur- ing as high as 3200 parts per million of carbonate. In general, greater deposits occurred at or near the surface in those tanks having the highest water tables. The same was true at the San Bernardino station, although the bicarbonates exceeded the carbonates in amount, which was the opposite of the Santa Ana condition. The pH values do not indicate an excessively alkaline reaction. CONSUMPTIVE USE OF WATER Evaporation from Soil Surfaces in Tanks In making studies of evaporation from bare soils at the Santa Ana station, distribution of soil moisture under natural conditions as found at the station site determined the initial maximum depth to the water table in the first set of tanks. In excavating around the tanks as they were filled, the upper 15 inches of soil was observed to be moist from previous rains, while the soil from 15 to 30 inches iu depth was found to be extremely dry. Below this dry belt was capillary moisture arising from the perched water table found at a depth of 6 to 7 feet. It was evident, therefore, that the limit of capillary rise in undisturbed soil with which the tanks were filled was the difference between the depth to the water table and the lower limit of the dry area, or slightly less than 4 feet. This measure was, therefore, adopted as the depth to the lowest water tables in the soil evaporation tanks. From this 4-foot water table, no soil evaporation occurred at any time during the warm summer months between May and October. Data regarding Aveekly amounts of evaporation from- soil surfaces obtained at the Santa Ana station, where water tables were at different depths, are found in Table 11. Monthly data relating to the same tanks are given in Tables 13 and 14. No losses by evaporation occurred when the water table w'as at a depth of 4 feet, but there were small losses when it was raised to 3 feet and still greater losses at 2-foot depths, confirming the initial conclusion that the limit of capillary rise was about 4 feet. For a six- month period during the winter of 1929-30, when evaporation was at its lowest, the total evaporation from the tanks having 3-foot water tables averaged but 0.913 acre-inch per acre. For the same period, evaporation from tanks having water tables at a 2-foot depth was 1.775 acre-inches per acre. 4—4503 50 DIVISION OF WATER RESOURCES In order to liave a coniparisou of evaporations from both disturbed and undisturbed soils, further tests were carried on with soil looselj^ settled in water as the tanks were filled. Diflt'erences due to the methods of filling the tanks became apparent immediately at the outset. Although both sets of tanks had water tables at the same depth, the moisture content in the loosely filled soil was enough to keep the soil surface moist, Avhile the surface in tanks of undisturbed soil was dry. For comparison of monthly records of soil evaporation under the two conditions of soil structure, further reference is made to Tables 13 and 14, which show the monthly use of water by all tanks. For the same six -month winter period of 1929-80, during which evaporation from undisturbed soil having a 2-foot depth to the water table was 1.775 acre-inches per acre, the disturbed soil with the same water table evaporated 6.889 acre-inches per acre, or nearly four times as much. In applying the results of these experiments to field conditions, it is obvious that only data secured from experiments with undisturbed soil should be used, and that measurements of evaporation from dis- turbed soil do not represent a true criterion for natural soil moisture losses. The large difference in the rate of evaporation for disturbed and undisturbed soils, indicates the advisability of further experimental work of this character. It also seems to cast doubt on the accuracy of results of some previous experiments along the same line. Use of Water by Salt Grass Salt grass {Distichlis spicata) is most often found in somewhat alkalied areas of shallow water table, the limit of depth from which the roots may draw moisture depending upon the soil type. In various investigations the limiting depth to water at which it has been found has varied. In one small locality with heavy soil, in the lower Santa Ana River basin, it was observed where the ground water was at a depth of 11 to 12 feet, but in general the limiting depth in lighter soils is about 6 feet. Moreover, it was found to exist only in those areas that were classified by the United States Bureau of Soils as containing some alkali. The growth of the plant is spread by means of a thick creeping root stalk within the upper few inches of soil from which finer roots extend downward in search of moisture. The stifle, light green leaves rise from each joint of the root stalk and sometimes spread to form a considerable sod. The grass has a distinctly salty taste and, although it is sometimes used for pasture, stock do not thrive on it. The grow- ing period in southern California is from February to December and although the grass dies or becomes dormant in the Avinter, there is some discharge from the water table throughout the winter months. Salt grass is not an excessive user of water. Its habit of growth in alkali soils has caused the plant to protect itself against toxic effects of alkali salts by a decreased rate of transpiration. Until recent years, the area devoted to salt grass in the lower Santa Ana River basin has been considerable, but the advent of drainage systems and extension of the cultivated area has crowded out the salt grass from a number of districts. Various salt-grass areas still exist, however, especially where the ground water continues to remain near the surface. This investigation was begun to measure the consumptive WATER LOSSES FROM WET AREAS 51 use of water by salt grass for comparison with nse of water by other wild growths in order to determine the net draft on the ground water supply by native vegetation. In experiments with salt grass grown in tanks at the Santa Ana station, distribution of moisture above the water table was determined by means of soil-moisture samples. Depth to water in the different tanks ranged from 1 to 5 feet. Reference to Table 10 shows the average soil moisture in the top foot of soil, when the water table was 1 foot from the ground surface, to be 27.1 per cent and that it decreased rapidly until the water table was 3 feet in depth, or near the limit of the capillary rise. With the water table below 3 feet there was little difference in the moisture content of the top foot of soil. It is evident, then, that there was greater soil evaporation in the tanks having the highest water tables. In the same tanks there was also greater transpiration because of a heavier crop of grass, due, in turn, to a higher moisture content. As consumptive use of water includes both soil evaporation and plant transpiration, it follows that plant growth in tanks having the highest water tables has the higher TABLE 10 RELATION OF SOIL MOISTURE TO DEPTH OF WATER TABLE IN TANKS AT SANTA ANA STATION Average soil moisture content in per cent Depth of sample in feet Depth to water table in soil tanks, in feet 1 2 3 5 1 2 27.1 15.5 21.3 6.7 9.7 21.4 7.6 10.7 3 18.7 4 20 5 5 . . 29 5 consumptive use. This is indicated in Plate V, which shows a compari- son of monthly use of water by each set of salt grass tanlvs. The set having the highest water table, shown by the solid bar, used the most water. It will be noted that bars representing tanks of disturbed soil show a greater use of water than do tanks of undisturbed soil, when both have the same depth to water table. The draft of salt grass on the ground water supply depends upon the depth to the water table and the soil structure. This may be estimated by comparison with results of tank experiments made dur- ing this investigation. When an irrigated area is extended to include uncultivated lands, the resulting net draft on the ground water supply is the difference between the amount of water required by cultivated crops and by the indigenous growth which the cultivation replaces. If the cultivated crop uses no more water than the native growth in the same area, no depletion results because of the change. Practical experience and scientifie experiments have indicated the necessary water requirements of crops, but little information is available as to the consumptive use of water by noneconomic plant life. 52 DIVISION OF WATER RESOURCES PLATE V MONTHLY USE OF WATER BY SALT GRASS IN TANKS HAVING VARIOUS DEPTHS TO WATER TABLE. Although the presence of salt grass is always an indicator of ground water, these experiments have demonstrated that its consump- tive use is not excessive when compared with water requirements of many cultivated crops. In general, farming operations are conducted on water-free soil of sufficient depth to allow ample root development. The average depth to free water naturally varies with each locality, but a minimum of 5 or 6 feet is considered a safe depth for many field crops. For the 12-month period ending April 30, 1932, salt grass grown in tanks having a depth of 5 feet to water table, used an average of about 22 acre-inches of water, including rainfall. During this period, conditions were the same as in natural salt-grass areas. This consumptive use is no more than that used by various crops of low water requirement, and is less than amounts required by alfalfa, citrus, or walnuts. In tanks having a water-table depth of 2 feet, the 12-month consumptive use for the same period was about 36 acre-inches per acre, which is sufficient, with careful management, to produce a fair crop of alfalfa. In most salt-grass areas in the Santa Ana basin the ground water occurs at depths exceeding 4 feet and the average seasonal draft is, therefore, Ioav. It is concluded, therefore, that the yearly water requirement of salt grass in this area is generally less than that of cropped lands. Data on the weekly use of water by salt grass at the Santa Ana station from May 7, 1929, to November 3, 1931, are given in Tables 11 and 12. On the latter date, readings at the station were discontinued, ■ORNIA, MAY, 1929, TO SEPTEMBER, 1930 1 e (ith fixed water table four feet Bare soil with fi-\ed water table two feet iw the ground surface below the ground surface Tank Tank Mean Tank Tank Tank Me&n No. 11 No. 12 No. 13 No. 14 No. 15 0.000 0 180 0.095 .000 000 .000 .277 .127 .066 .117 .060 .042 .022 .021 115 .191 .333 265 .444 .462 .551 .508 .508 .097 .179 .234 .519 .482 .366 .587 .636 .823 .944 .870 .057 .088 .138 .311 .344 .315 .482 .621 .790 .742 .716 ' '"o'^i" ""'"0'449" " ' 6"353" 0'352 .439 .373 .620 .848 .866 1 465 1.060 579 .561 .518 .542 .824 1.197 .854 593 .689 .657 .392 .738 1 336 .822 .308 .625 .512 .488 .514 .749 .584 .466 .276 .419 .552 .450 .685 .562 .273 .270 .295 .318 .524 .546 .463 .138 .515 .352 .531 .479 .748 .5S6 415 .737 .574 .572 372 696 .547 .243 .646 .431 .499 .502 .588 .530 .259 .487 .326 .490 .385 .546 .474 147 .343 .188 .403 .438 641 .494 297 .123 .278 .511 .417 .600 .509 196 .021 .186 435 .385 .492 .437 .173 .000 .139 .403 .309 .491 .401 .177 .000 .139 .371 .310 .395 .359 .138 .036 .148 .295 .245 .197 .246 .107 .070 .131 .159 .266 .324 .250 .138 .022 .109 .128 .246 .175 .183 .099 .222 .172 .211 .192 .386 .263 .114 .117 .136 .286 .267 .363 .305 1 .148 .095 .169 .272 .287 277 .275 .043 .063 .063 .137 .234 .085 .152 .000 .010 .021 .063 .140 .097 .100 .000 Oil .039 .137 .288 .160 .195 .021 .010 .067 .042 ^ .235 .160 .146 .053 .000 .046 .106 .277 .181 .188 .125 .032 .095 .126 .211 .256 .198 063 .010 .081 .148 .171 .255 .191 .127 .021 .105 .169 265 .203 .212 .095 .000 .081 .181 .203 .331 .238 .074 .000 .046 .203 .448 .159 .270 .084 .074 .091 .192 .320 .201 .238 201 .064 .209 .234 .288 .385 .302 159 .115 .172 .256 .320 .330 .302 148 .159 .251 .290 .394 .417 .367 276 .190 .297 .278 .331 .341 .317 212 .212 .240 .299 .351 .471 .374 191 .168 .198 .299 .246 .268 .271 180 .170 .247 .332 .278 .394 .335 179 .168 .246 .437 .373 .416 .409 306 .233 .318 .362 .426 534 .441 .305 .180 .320 .383 .471 .578 .477 .295 .222 .342 .373 .449 .524 .449 255 .222 .329 .340 .309 .426 358 .319 .243 .335 .361 .202 .439 .334 329 .274 .381 .394 . 277 .589 .420 .306 .316 .391 .405 .342 514 .420 .404 .349 .470 .405 .406 .503 .438 382 371 .463 .459 .514 .727 .567 .456 360 .488 .415 .428 .514 .452 318 .382 .467 .426 .469 .621 .505 445 .284 .395 .395 .405 .438 .413 318 .284 .332 .321 352 .383 .352 276 .349 .413 .375 .427 .535 .446 349 338 .438 .427 .427 .514 .456 414 320 .418 .386 437 .492 .438 265 267 .322 .342 .288 .405 .345 .339 244 .328 .322 .247 .352 .307 286 233 .300 .311 .299 .394 .335 1 TABLE 11 RECORD OF WEEKLY EVAPORATION FROM SOIL AND USE OF WATER BY SALT GRASS IN TANKS AT SANTA ANA, CALIFORNU, MAY, 1929. TO SEPTEMBER, 1930> Week ending 1929- May May May May June JuDe June June July July July July July Aug. Aug. Aug. Aug. Sept. Sept. Spet. Sept. Oct. Oct. Oct. Oct. Oct. Nov. Nov. Nov. Nov. Dec. Evaporation from bare soil and use of water by salt grass in acre-incbes per acre Dec. 10 Dec. 17 - Dec. 24 Dec. 31 30- Jan. 14 . Jan. 21 . Jan. 28 Feb. 4 Feb. 11 Feb. 18 Feb. 25 Mar. 4 Mar. 11.. .. Mar. 18 ... . Mar. 25 .... April 1 April 8 ' April 15 April22 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-... Aug. 12 . Aug. 19... . Aug. 26 Sept. 2 Sept. 9 Sept. 16 Sept.23 Sept.30... Bare soil with fi-\ed water table three feet below the ground surface Tank No. 1 Tank No. 2 Tank No. 3 Mean Xo evaporation from Tanks Nos. 1, 2 and 3 with water table at depth of four feet, May 1 to October 1, 1929 0.115 .084 .084 .074 .075 .105 .074 .081 .074 .004 .063 .053 .074 .074 .074 .011 .010 .010 .032 .031 .021 .064 .043 .021 .021 .021 .021 .000 .021 .000 .084 .042 .010 .032 .000 .011 .000 .042 .022 Oil .042 .021 .064 .010 .042 .042 .042 .033 .126 ,021 .032 .031 0 890 0.413 306 .499 .180 .254 064 ,095 .106 .180 .053 .064 .084 .126 032 .042 .084 094 ,031 ,074 .043 .085 .000 .021 ,000 .075 ,000 .032 ,000 .042 ,000 .010 .000 .032 ,000 .010 ,000 .021 .000 .021 .000 ,021 ,000 ,022 ,000 ,042 .000 021 OOO ,032 ,000 ,052 000 ,000 000 ,053 ,000 031 .000 ,032 .021 ,032 .011 .042 ,000 .052 oil ,021 .000 .000 oil ,032 .000 ,000 .000 .011 .010 .000 .021 ,000 .021 ,063 .000 .003 .032 .084 .000 .053 ,000 .032 ,000 .000 ,000 .042 .000 .011 .000 ,042 ,000 ,042 ,000 ,073 ,000 .074 .473 ,296 .173 .078 ,120 ,074 ,095 ,053 ,084 .056 .064 .025 .060 ,036 ,039 007 ,014 .007 .018 .017 ,014 ,029 ,028 OH 018 ,024 007 018 017 ,011 ,046 ,032 .021 ,021 .000 ,018 ,000 .018 Oil .010 042 .028 .060 .021 025 .014 028 .015 056 ,021 036 035 Bare soil with fixed water table two feet below the ground surface Tank No 4 .561 .445 .359 .275 ,296 ,233 .222 .232 085 .190 ,169 ,180 ,169 .170 .158 .157 .159 .158 .094 ,032 .105 .127 ,126 ,106 .147 .127 .126 ,106 ,127 ,075 .053 .053 .106 ,063 ,116 ,074 ,031 .021 .032 .021 .052 .074 ,021 .031 ,064 .010 ,053 ,032 ,063 .074 .084 143 .063 ,074 ,042 ,095 ,073 105 .105 .074 095 ,095 .095 .137 .105 .116 .084 .105 .086 127 ,074 ,094 095 Tank No. 5 0 600 ,597 ,523 .450 .449 .449 .355 .323 ,251 .229 ,188 ,177 ,167 293 .251 ,249 ,218 .241 ,261 ,177 ,W6 ,157 .166 ,156 ,125 ,178 ,187 .156 ,135 ,104 .137 .074 ,063 .104 .116 .105 .074 ,010 ,000 .043 .031 .063 .042 ,021 .043 .074 .041 ,064 ,063 115 ,095 178 ,146 ,053 ,106 .104 116 126 .145 .105 146 .156 .094 .125 .125 .125 ,136 ,137 ,135 ,157 ,177 ,137 104 125 Tank No. 6 0 274 263 .232 ,223 ,210 .136 ,158 ,115 .180 ,168 ,180 -147 ,169 ,136 ,158 .126 157 155 184 .020 .084 105 ,073 .084 ,106 ,115 ,096 ,095 ,095 ,096 ,064 ,074 .042 .096 .063 .074 .073 .032 .042 .032 .021 .063 .063 .042 .042 .032 ,031 ,042 .064 .021 ,073 ,063 ,116 063 063 ,031 ,063 064 084 ,084 ,053 ,094 ,084 ,085 ,126 ,053 094 074 073 085 085 105 074 084 0,541 ,470 ,400 ,344 ,311 ,294 ,249 ,220 ,221 ,161 .186 .164 .172 .199 .193 .178 .177 .185 .201 097 084 ,122 .122 .122 .112 .147 .137 ,126 .112 .109 .092 .067 .053 .101 .081 .098 .074 .024 .021 Salt grass with fixed water table two feet below the ground surface Tank No. 7 .024 .059 .060 ,028 ,039 .057 .027 ,053 053 .066 .081 .108 , 135 ,060 077 ,059 ,091 ,088 111 ,098 .091 .115 ,091 .102 ,129 094 .115 ,098 ,104 ,109 ,133 .105 091 101 0 296 ,275 275 .371 ,626 964 ,975 1 632 I 281 1 217 1 282 1 325 1 208 1 154 1 048 1,165 1,101 1 144 ,744 816 .646 .785 890 ,667 .848 ,636 .647 .521 .413 .317 .286 .434 .435 ■ .297 .148 .137 .192 .243 .211 ,286 ,222 ,201 265 ,223 ,328 ,435 .499 ,540 ,668 678 ,382 .647 .721 ,953 954 1 134 ,890 ,974 1 174 1,133 1 521 1,454 1 155 1 303 1 228 1,068 1 453 1 312 1 250 996 ,891 Tank No. 8 0 862 ,561 ,293 .429 .481 ,398 .670 1 167 1 178 1 251 I 442 1,462 1 315 1 283 1 271 1 314 1 314 1,430 840 .945 .661 ,881 ,998 735 ,736 ,840 ,923 .661 .713 ,565 .429 ,324 ,313 ,471 ,460 .345 .031 .000 .105 .250 ,187 ,313 ,136 ,188 .281 229 ,387 .491 ,544 ,650 .800 .756 .386 ,713 ,788 1.062 1 050 1.231 944 1,051 1 336 1.272 1 703 1 555 1 513 1 597 1 125 1,167 1 578 1 410 1 314 1 050 Tank No. 9 .801 0 699 1,003 ,624 ,741 1 111 1 007 .975 1,461 1,154 1,132 1 323 1 335 1.176 1,334 1,166 1,282 1-227 1 292 868 ,890 ,605 ,838 933 689 ,689 ,817 ,784 572 .593 .478 .392 .265 .307 ,434 ,392 ,329 ,127 063 .148 .244 .169 .318 .146 ,211 ,275 233 ,392 ,520 ,539 ,732 ,943 921 478 764 .953 1,048 ,995 1 228 890 964 1 227 I 217 1 579 1 505 1 398 1 452 1 187 1 123 1 527 1 389 1 314 1,049 953 818 0 619 613 397 514 ,739 ,790 873 1,420 1,204 1 200 1,349 1,374 1 233 1 257 1 162 1 254 1,214 1 289 ,817 ,884 637 835 940 697 ,698 ,831 ,852 ,623 ,651 621 ,411 ,302 ,302 ,446 ,429 .324 .102 .067 .148 .246 ,189 ,306 .169 .200 .274 228 ,369 ,482 ,527 ,641 ,804 ,785 ,415 ,708 ,821 1,021 1 000 1 198 908 ,996 I 246 1 207 1 601 1 505 1 355 1,451 1 180 1 119 1 519 1 370 1 293 1,032 937 ,846 Salt grass with fixed water table four feet below the ground surface Tank No. 10 Tank .No. 11 0 105 074 ,053 .032 ,053 ,063 ,064 ,223 216 ,314 ,414 764 ,996 ,773 ,770 1,049 ,413 ,690 ,604 ,514 ,343 .403 540 403 ,233 ,073 ,414 ,340 243 .240 .270 217 .166 ,196 ,176 ,265 .084 052 ,106 ,169 084 ,127 ,169 .168 .147 .063 .116 .361 ,243 446 424 ,297 234 392 ,393 .415 .476 510 510 444 540 552 656 637 647 ,700 457 ,393 ,615 626 ,520 .435 402 ,382 0 000 000 000 000 022 021 115 191 333 265 444 462 561 508 508 439 579 593 308 -466 -273 -138 445 -243 259 147 297 196 173 177 -138 -107 -138 099 114 148 -043 000 000 021 -053 125 063 127 095 074 084 201 159 148 276 212 191 180 179 306 305 295 255 319 329 306 404 382 456 318 445 318 276 349 414 265 339 286 Tank No. 12 0 180 277 -127 .096 .097 ,179 .234 .519 ,482 .366 587 ,636 ,823 ,944 870 373 .561 ,689 ,625 ,276 ,270 ,515 .737 .646 .487 ,343 ,123 ,021 .000 .000 .036 .070 .022 .222 .117 .095 .063 ,010 Oil ,010 .000 .032 .010 .021 .000 .000 ,074 ,064 ,115 ,159 ,190 ,212 .168 .170 .168 ,233 ,180 ,222 ,222 ,243 274 316 ,349 371 360 382 284 ,284 349 338 320 ,267 244 233 0 095 .117 ,060 .042 .057 .088 .138 .311 .344 .315 .482 .621 .790 742 716 620 518 ,657 512 ,419 ,295 ,352 674 .431 ,326 .188 ,278 .186 ,139 .139 ,148 .131 .109 .172 .136 .169 .063 .021 ,039 ,067 ,046 095 ,081 105 ,081 ,046 .091 .209 ,172 251 ,297 .240 .108 247 246 .318 .320 ,342 ,329 ,335 .381 391 470 ,463 .488 .467 .395 .332 .413 .438 ,418 ,322 ,328 300 Bare soil with fixed water table two feet below the ground surface Tank No. 13 ,542 ,392 .488 ,552 ,318 ,531 572 ,499 ,490 ,403 511 435 403 371 ,295 ,159 ,128 ,211 ,286 .137 .063 .137 .042 .106 .126 .148 ,169 ,181 ,203 .192 ,234 ,256 .290 278 .299 299 332 ,437 ,362 ,383 373 ,340 ,361 ,394 ,405 .405 ,459 415 .426 395 .321 375 ,427 386 ,342 .322 .311 Tank Xo. 14 Tank Xo. 15 0 449 866 824 738 514 450 524 479 372 502 ,385 ,438 .417 ,385 ,309 310 245 ,206 ,246 192 267 234 .140 .235 .277 .211 .171 ,265 ,203 ,448 320 ,288 320 394 331 351 ,246 278 ,373 426 471 449 309 ,202 .277 342 406 ,514 428 469 405 352 427 427 437 288 247 299 0 353 1 465 1 197 1 336 749 685 546 748 696 588 ,546 641 600 ,492 ,491 395 ,197 ,324 ,175 386 ,363 .277 085 .097 .160 .160 .181 .256 ,255 203 331 .159 ,201 385 330 ,417 ,341 ,471 ,268 .394 .416 534 578 .524 ,426 ,439 589 514 .503 .727 514 .621 .438 .383 535 514 ,492 .405 .352 .394 ' All tanks covered during rains. Tanks Nos. 1 to 12, inclusive, contain undisturbed soil. Tanks Nos. 13 to 15, inclusive, contain disturbed soil. 4503— Bet. pp. 52-53 TABLE 12 RECORD OF WEEKLY USE OF WATER BY SALT GRASS IN TANKS AT SANTA ANA, CALIFORNIA, OCTOBER, 1930, TO NOVEMBER, 1931' Week ending 1930- Oct. 7. Oct. 14. Oct. 21- Oct. 28. Nov. 4. Nov. 11. Nov. 18. Nov. 25. Dec. 2. Dec. 9. Deo. 16. Dec. 23.. Dec. 30.. 1931- Jan. 6.. Jan. 13.. Jan. 20.. Jan. 27.. Feb. 3.. Feb. 10.. Feb. 17.. Feb. 24.. Mar. 3.. Mar. 10.. Mar. 17.. Mar. 24.. Mar. 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.. July 7.. July 14-. July 21-- July 28-- Aug. 4-- Aug. 11-- Aug. 18-. Aug. 25.. Sept. 1.. Sept. 8.. Sept. 15.. .Sept. 22.. Sept. 29.. Oct. Oct. Oct. Oct. No 13. 20. 27. 3. Use of water by salt grass in acre-inches per acre Salt grass with fixed water table three feet below the ground surface Tank No.l 0 022 063 063 052 .064 .031 .085 .094 .032 075 044 ,032 .053 .042 .021 Oil 042 Oil .010 Oil .021 .063 .063 073 .158 .265 .709 .583 ,636 763 ,826 646 637 509 678 520 467 ,318 ,530 382 424 458 .466 ,414 .403 329 .338 .286 ,361 Tank No. 2 0 021 021 Oil 00 00 00 00 .00 00 00 00 ,021 021 021 00 ,00 021 00 00 ,00 021 .148 137 042 074 116 ,085 126 159 .116 Tank No. 3 0 021 032 ,021 ,00 .00 00 00 00 ,021 032 021 063 ,010 Oil ,021 063 042 021 Oil 00 ,073 158 ,064 126 105 032 095 169 ,243 ,064 .074 ,128 ,212 .179 666 602 614 572 635 561 487 404 615 308 424 424 403 402 360 361 256 317 ,371 0 021 039 032 017 ,021 010 028 031 018 036 022 039 028 025 014 .025 035 Oil 007 004 038 123 088 080 112 138 090 148 .201 .090 ,300 ,276 ,322 427 ,621 536 569 530 622 547 477 372 566 354 417 436 421 402 382 336 307 296 354 Salt grass with fixed water table two feet below the ground surface Tank No. 4 0,063 095 085 063 096 084 127 ,084 ,032 084 042 095 105 073 042 042 063 053 063 117 105 170 264 244 303 403 .530 ,647 688 ,477 328 ,593 698 ,762 732 679 ,774 ,944 1 163 1 038 1 028 1 060 1 164 1 102 923 710 1 059 891 837 859 815 783 784 572 552 477 ,709 Tank No. 5 0 084 156 063 084 lib 094 136 073 Oil 074 031 053 146 063 021 053 104 137 094 198 219 ,281 408 399 492 807 757 955 1 016 431 ,397 862 ,997 912 987 817 966 1 219 1,419 1 261 1 272 1 252 1 387 1 251 1 062 293 997 978 999 914 831 839 629 534 525 Tank No. 6 0 063 116 063 126 032 ,063 094 064 031 053 063 063 ,116 042 053 031 ,043 042 ,126 042 052 ,201 275 371 255 ,192 327 ,456 510 552 508 604 794 911 890 869 912 995 043 839 679 857 753 721 742 720 646 658 519 552 370 594 0 070 ,122 070 091 081 080 1.9 074 ,025 ,070 .045 ,070 .122 ,059 .039 042 070 077 ,094 ,119 .125 ,226 ,336 ,322 ,398 ,605 496 626 693 388 306 694 .717 726 ,767 ,668 781 986 1 164 I 060 1 056 1 075 1 182 1 099 ,941 732 1 070 880 845 867 ,816 ,753 ,760 573 ,546 457 ,701 Salt grass with fixed water table one foot below the ground surface Tank No. 7 0 668 656 551 478 424 446 317 180 232 253 318 286 180 222 318 372 425 392 476 561 625 .763 806 350 360 615 742 806 901 817 1 048 1 387 1 769 1 568 1 642 1 685 1 845 1 707 1 409 1 282 1 747 1 302 1 240 1 218 1 081 974 837 722 658 530 .783 Tank No. 8 0 649 880 685 482 409 692 344 083 230 283 376 230 021 199 355 397 418 335 493 629 ,619 777 829 346 252 894 1 072 975 1 262 1 031 1 303 1 725 1 923 1 650 1 756 1 702 1 818 1 577 1 347 1 018 1,618 1 051 1 061 1 061 966 819 682 619 555 503 713 Tank No. 9 0 605 646 .509 605 445 509 327 234 ,275 ,275 ,411 ,266 211 ,274 359 423 425 424 530 635 699 880 901 287 381 912 1 038 933 1 132 912 I 101 1 536 1 727 1 546 1 674 1 676 1 824 1 601 1 389 1 060 1 717 1 165 1 240 1 134 1 039 732 763 710 625 642 .784 0 641 727 582 522 426 649 ,329 ,246 270 ,368 260 ,137 ,232 344 397 423 384 500 60S ,845 ,327 ,331 807 951 906 1 098 920 1 161 1 549 1 806 1 588 1 691 1 687 1 829 1 628 1,382 1 120 1,094 1 169 1 180 1 134 1 029 842 ,761 684 613 526 760 Salt grass with fixed water table five feet below the ground surface Tank No. 10 0,264 ,213 ,191 148 158 .213 .074 ,095 ,073 ,074 .042 .107 .202 .224 .180 ,213 .234 .191 .190 .191 .415 ,477 488 ,169 ,213 351 435 .404 ,433 478 563 ,646 ,774 721 594 520 ,751 550 563 636 ,456 650 608 ,572 444 ,327 393 Tank No. 11 0 169 213 221 105 096 116 084 063 062 053 ,084 074 148 180 191 147 138 212 275 095 202 245 318 371 222 126 232 403 509 340 457 466 572 488 413 393 466 349 360 457 361 295 338 316 244 274 ,316 Tank No. 12 0,234 ,200 095 ,180 ,126 106 074 ,096 ,126 ,052 .131 .148 148 095 148 191 063 ,159 169 181 117 ,159 ,148 ,00 084 ,201 147 200 551 ,413 ,445 426 404 389 ,456 ,338 ,467 668 244 264 ,307 286 ,285 294 254 234 226 0 219 209 ,169 144 126 ,145 ,077 086 084 060 086 127 175 160 164 159 148 177 183 173 223 283 304 088 208 298 377 388 246 268 314 416 611 480 580 531 606 533 488 417 558 522 389 449 371 377 377 394 314 278 ,312 Salt grass with fixed water table two feet below the ground surface Tank No. 13 0 268 310 267 .276 .311 .278 449 391 181 321 320 383 374 236 159 191 235 267 189 266 329 393 493 437 524 567 599 718 759 577 371 557 729 718 792 ,727 ,824 .908 1,015 1 005 I 026 1 080 1 111 I 134 984 866 1 026 1 144 1 261 1 145 973 899 866 664 ,643 557 771 Tank No. 14 0 244 319 244 ,288 ,396 ,395 439 ,431 ,298 ,395 471 ,588 492 235 128 192 224 236 ,140 362 342 459 689 656 689 ,610 ,654 .769 ,844 535 373 535 674 706 611 654 717 824 ,985 1 006 973 1 060 1,048 983 866 728 919 889 673 856 759 792 739 600 556 492 610 Tank No. 15 0 266 299 322 320 406 405 427 492 266 374 406 ,513 ,395 ,234 084 169 256 ,299 ,160 ,364 503 ,695 867 685 663 652 ,739 910 867 480 364 600 791 866 941 856 1 037 1 348 I 486 1 401 1 346 1 454 I 369 1 348 1 153 930 I 411 1 069 I 047 1 036 995 388 878 656 689 512 770 'Tanks Nos. 1 to 15 inclusive covered during rains. Tanks Nos. 1 to 12, inclusive, contained undisturbed soil; Nos. 13 to 15, inclusive, contained disturbed soil. 4503— Bet. pp. 52-53 TABLE 13 SUMMARY SHOWING MONTHLY USE OF WATER BY SALT GRASS AND TULES AND EVAPORATION FROM SOIL AND WATER SURFACES, MAY, 1929, TO APRIL, 1930, IN TANKS AT SANTA ANA, CALIFORNIA" Tank No. Content of tank Deptli to water table, in feet Diameter of tank, in inches Amount of water used in inches of depth Number of months of record Total amount used, in inches Per cent of May June July August September October November December January February March April Tank No. 16 Tank No. 20 1 4-3 4-3 4-3 4-3 2 2 2 2 2 2 2 2 4 4 4 4 2 2 2 2 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 25 1/2 48 No evaporation from Tanks Nos. 1, 2 and 3 with water table at depth of four feet. May 1 to October 1, 1929 (=) (=) (') 0 474 815 453 581 3 319 3.737 3 571 3 542 1 907 1 408 1.792 1.702 2.069 2.256 3,038 2 454 5,762 23,750 5.654 0.399 1.493 1,399 1 097 559 708 ,421 563 3 413 3 696 3 447 3 519 1 377 1 164 2 457 1,666 2 221 1 857 2,770 2 283 5.640 28.380 6.060 0.370 .338 .443 384 444 552 371 456 2 662 2 861 2 458 2.660 1.326 869 .117 .771 1,695 1.431 1.957 1.694 4 884 23,350 5.256 0.275 .074 .265 ,205 339 ,462 ,307 ,369 1 630 1,736 1 557 1.641 .914 .621 .467 ,634 .911 1.067 1.263 1 080 3 060 11.300 3 444 0.179 .000 .126 .102 .242 .200 .242 .228 .858 .554 .752 .721 .549 .191 .189 .310 .651 1.067 .673 .797 1,860 1,860 2.280 0 148 000 074 074 189 .189 179 186 984 896 867 .916 612 347 042 334 454 1 829 916 733 2 436 3.610 2.872 0,085 ,000 ,137 .074 148 201 .147 .165 1 293 1 441 1,473 1,402 ,729 454 ,148 .444 862 1.418 1,118 1 133 3 384 6 020 4 476 0 084 000 .137 ,074 316 536 ,263 371 2 502 2 862 3,326 2.897 1.463 ,837 ,719 1 006 1,219 1,460 1.677 1.452 4 968 17 590 6 048 7 7 7 7 12 12 12 12 12 12 12 12 12 12 12 12 9 9 9 9 liH 9 12 2 3 2.010 7.7 6.7 4 2 160 2 418 1 076 1 885 1 440 2.417 3,501 2 453 .275 000 .702 .326 1 099 1 555 ,663 1.106 4 916 3 296 4 978 4.397 .477 .592 1 304 .791 0.709 .908 .727 .781 5.630 5 964 5 410 5 635 2,714 1,866 2 714 2,431 0 696 1.084 .651 810 5 019 5.908 5 666 5 531 3.451 2 330 3 097 2 959 1.834 2 792 4.223 2,950 8,328 23.460 8.904 5 7.501 11 2 10 6 7 8 -- 9 - Salt grass sod 36 314 56 0 50. 0 10 11 12- Mean 13 Salt grass sod Baresoil 13.374 21.4 19.0 14 15 Mean Bare soil 14 576 62.002 139.320 70.514 36 2 100 0 345 5 110,4 32 5 16- 5 574 7,910 8.196 19 Round stem tules in submerged soil* 309 7 20 Water in standard Weather Bureau pan 8 394 8 234 8 892 100.0 'Tanks Nos. 1 to 12, inclusive, contained undisturbed soil; tanks Nos. 13 to 15. inclusive, contained disturbed soil. All tanks covered during rains. - Water table raised from four to three feet, October 1, 1929. ' Record began May 8, 1929. ' Not applicable to field conditione. 4503— Bet. pp. 52-53 TABLE 14 SUMMARY SHOWING MONTHLY USE OF WATER BY SALT GRASS. TULES, CAT-TAILS, WILLOWS, AND WIRE RUSH, AND EVAPORATION FROM SOIL AND WATER SURFACES, MAY, 1930, TO APRIL, 1931. IN TANKS AT SANTA ANA, CALIFORNIA* ' Tank No. I--- 2.-- 3 -- Mean. 4 -- 6..- 6..- Mean. 9 Mean 10... 11 . 12 - Mean 13 ., 14 .. 15 . Mean 16 .. 19 .. 20 -. 21... 22- - 23 -. 24-.. 25 .. Content of tank Bare soil planted to salt grass October, 1930 Bare soil planted to salt grass October. 1930 Bare soil planted to salt grass October. 1930 Bare soil planted to salt grass October, 1930 Bare soil planted to salt grass October, 1930 Bare soil planted to salt grass October. 1930 Bare soil planted to salt grass October, 1930 Bare soil planted to salt grass October. 1930 Salt grass sod'. Halt grass sod'- Salt grass sod' Salt grass sod' - Salt grass sod=. Salt grass sod-. Salt grass sod ^ Salt grass sod*. Bnre soil planted to salt grass October. 1930- Baresoil planted to salt grass October. 1930- Bare soil planted to salt grass October, 1930- Bare soil planted to salt grass October, 1930^ \Vater in circular sunken tank Hound stem tides in submerged soil' Water in s andard Weather Bureau pan. Triangular stem tules in submerged soil' Cat-tails in submerged soil'. Round stem tulea in submerged soil' Willow* - Wire rush* Depth to water table, in feet 2-1 2-1 2-1 4-5 4-5 4-5 4-5 Diameter of tank. in inches 2S 1/16 2H 1/lfi 23 1/16 23 1 16 23 Mfi 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/10 25 1/2 48 25 1/2 25 1/2 72 72 25 1/2 Amount of water used in inches of depth May 0 147 043 147 358 398 .284 3 180 3 485 3 709 3 458 1 655 1 003 .792 1 600 1 590 1.880 1 090 5 988 22 565 6 792 12 301 11 875 10 230 3 275 June 0 075 021 .043 368 .564 295 4 426 4 834 4 563 2 173 1 292 1 024 1 575 1.366 2.138 1 C93 li 440 23 088 6 948 15 896 13 520 12 428 4.988 July 0 138 074 242 485 573 421 5 740 6 664 0 281 2 720 1 707 1 545 1 854 1 914 2 472 2 080 7 824 28 595 8 544 23 286 16 906 17 211 7 343 August 0 158 .000 095 .084 422 586 326 5 697 6 056 5 894 2,461 1 473 1 414 1 699 1 792 2 213 1 901 6.744 24 793 7 392 24 292 14 924 15 946 7 803 5 735 September 0 221 000 242 154 422 595 390 4 314 4 600 4 505 1 898 1 410 1,170 1 489 1 399 1 782 1 557 5 588 19 754 5.828 21 942 11.210 13 058 6 628 6 427 October 0 232 .053 074 349 .429 368 .382 1 250 1 288 1 308 1 302 5 032 18 352 5 500 21 012 10 140 12 043 5 359 5 682 November December 0 274 .000 021 .380 388 285 I 187 881 ,784 ,951 1 407 1 741 1,751 1 033 3 816 12 956 4 262 15 031 7 427 8 602 3 545 5,031 0 204 042 ,126 336 314 295 1 834 2 084 2 066 1 995 635 430 ,549 538 1 515 2 063 1 805 1 794 3 144 8 024 3 312 6 405 5 214 3 322 2,115 4 233 January 0 116 043 158 ,221 ,305 1,141 1 129 1 344 274 .242 .938 .896 .882 .905 2.194 3 730 2 890 2 894 3 007 2 587 2^654 February 0 074 084 168 444 .730 336 830 508 1 263 2.472 2,365 2,736 2 165 2 100 2 201 2 005 2,950 March 0 601 ,454 .401 1.267 2.231 1 749 2.035 2 084 2.247 2.122 .891 729 710 2 191 2 514 3,199 2,635 5 454 5 183 5 778 5 901 0 847 8 553 3 922 6 781 April 0-517 ,571 2 426 3,214 1 145 2,262 2 618 2 581 2 820 1,602 773 ,450 2 759 2,909 3,081 2 916 5 212 8 386 6,016 9 789 7 891 11 508 5 724 7 761 Number of months of record Total amount used, in inches 59 908 177 790 65 998 160 974 111 067 117 689 52 707 40,260 Per cent of Tank No. 16 100 0 290 8 110 2 268 7 185 4 190 4 91 3 110,7 Tank No. 20 90 8 269 4 100,0 243 9 168 3 178 3 83 5 105 8 1 Water table raised from two feet to one foot October, 1930, > Water table lowered from four to 6ve feet October, 1930. ■ Tanks Nos. 1 to 12, inclusive, contain undi.sturbcd soil. Tanks Nos. 13 to 15, inclusive, contain disturbed soil. * Rainfallinckided in water used but changes in soil moisture on account of rainfall disregarded. 'Tanks Nos. 1 to 15, inclusive, covered during rains, • Totals are not given for soil moisture tanks as conditions are not comparable throughout the vear due to changing water levels and planting new grass, » Not applicable to field conditions. 4503 — Bet, pp. 52-53 SUMMARY SHOWING MONTHLY USE OF WATER BY SALT GRASS, TULES, CAT-TAILS, WILLOWS AND WIRE RUSH, AND EVAPORATION FROM WATER SURFACES, MAY, 1931, TO APRIL, 1932; IN TANKS AT SANTA ANA, CALIFORNIA ' • Content of tank Depth to water table, in feet Diameter of tank, in inches Amount of water used in inches of depth Number of months of record Total amount used. in inches Per cent of Tank No. May June July August September October November December January February March April Tank No. 16 Tank No. 20 1 2 3 Mean i 6 Salt grass sod- 3 3 3 3 2 '2 2 2 1 1 1 1 S 5 5 5 2 2 2 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1, 16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/10 23 1/16 23 1/16 25 1/2 48 25 1/2 25 1/2 72 72 25 1/2 48 3 041 .964 1 238 1 748 3 815 4 747 2 997 3 853 5 318 6 382 5 636 5 779 2 608 1.312 1 099 1.673 3.731 3 382 5 037 4 043 6.850 27 057 8 050 24 777 14.940 19.073 4 484 10 304 7 318 2.725 2.153 2.667 2 515 4 809 5.771 4.111 4 »97 7 546 7,683 7 482 7,570 3 415 2 037 1 814 2 422 4 725 4 514 6 222 5 154 8 100 31 564 8,904 31,697 20,208 19 681 4 602 13,752 8,148 1,909 2,079 2 099 2 029 4 049 4 695 3,552 4 099 6.482 5.707 6 Oil 6 067 2 744 1.845 2.183 2.257 4 404 3 851 5 152 4 469 7 102 25 746 7.462 30 823 17,429 14 885 3,306 12 702 7,018 1 868 1 740 1 770 1 793 3 549 3 974 3 041 3 521 4 799 4 170 4 420 4 463 2 363 1 558 1 166 1 696 4 684 3 283 4 212 4 060 5,942 19. 372 6,206 29 382 14 978 12 431 2 702 10 729 5 834 1 558 I 483 1 453 1 498 2 786 2 990 2 343 2 706 3 202 2 768 3 106 3 025 1 968 1 309 1 154 1 477 3 105 2 676 2 663 2 915 4 266 14 240 4,698 20 408 12 055 7 304 1 476 8 254 4,642 1,831 1 832 1 841 1 835 2 225 2 367 2 266 2 286 2 101 1 782 1 964 1 949 2 086 1 683 1 558 1,769 2 633 2 546 2 288 2 489 2 734 6 089 3 094 6 015 5 307 5 063 1 655 4 853 2,698 1.436 1.834 2 329 1 647 2 132 1 748 I 842 " : 950 1 950 "' 1 893 1 294 1 594 ■2 557 1 215 -' 364 2 046 ,401 "761 581 1 602 3 509 2 730 1 568 2 397 ,815 1,065 1 583 1 902 2 643 3 288 3 652 3 194 2 947 2 626 3 646 3 040 2 578 2 212 1 740 2 177 2 164 2 720 2 612 2 499 2 811 1 657 2 312 2 260 3 504 6.052 -! 980 5 830 6 031 4 775 2 850 4 106 4 536 4.166 3.042 2 771 3.326 3 476 3 574 3 025 3 358 4 202 3 608 3.140 3 650 2 521 1 186 1 733 1 813 4 017 4.822 3 886 4 242 4 442 11 717 5 858 11 832 11 180 8 717 4 035 8 649 5.126 11 10 10 n 11 11 12 12 11 11 12 12 11 12 11 12 12 11 12 12 12 11 12 12 11 11 12 10 12 2 445 1,941 1,604 1 487 1 214 1 435 2 046 1,067 1,191 1 435 1547 1,685 1 616 840 1,108 1 010 .986 1 448 i 988 1 971 2 082 2.789 2.424 1 690 2 301 1.628 23 803 49 3 42.2 2,764 3 777 1 814 2 785 3 043 4 044 3 983 3 690 1 637 1.263 1 450 2.804 2,609 3 164 2.859 5 746 17 372 6 886 17 198 11 214 15 714 4 760 8.621 6 334 36 231 Mean 67 7 57 3 7 g 42.748 9 1 069 1 349 1.011 1.664 1.538 1 404 1.870 1 055 1 230 1.385 1.788 1 267 2 376 2.431 1.744 1,346 1,275 79 9 67 0 10 11 - ..- Salt grass sod 22 121 12 . ... 41 3 Salt grass sod. ... 35 0 13 Salt grass sod 14 36 443 53 524 162 986 63 232 183 992 117 483 109 804 32 915 S3 453 57 004 15 Salt grass sod Salt grass sod Water :n circular sunken tank Round stem tules in submerged soil'_ Water in standard Weather Bureau pan Triangular stem tules in submerged soil' Mean...._ 16 19 20 - 21 22 66 2 100 0 313 0 118.1 343 8 225 6 210 9 61 5 165 9 106 5 56 1 84.7 266.1 100.0 291.0 23 Round stem tules in submerged soil* Willow" '2 2 179.2 52 1 24 --- .705 25 Wire rush* _ . _ 5% NaCI solution in standard W. B. pan 28 1.484 2,004 90.2 'Tanks Nor. 1 to 12. inclusive contain undisturbed soil. Tanks Nos. 13 to 15, inclusive, contain disturbed soil. ' Wil!ow unhealthy and lost most of its leaves during latter part of the sumraer. 'Tanks Nos. 1 to 15, inclusive, covered during rains prior to December 1, I93I. except during the first half of November, 1931. ' Rainfall included in water used but changes in soil moisture on account of rainfall disregarded. ' Not appplicable to field conditions. From December 1, 1931 to May 1, 1932. all tanks were exposed to rainfall. 4503— Bet. pp. 52-53 WATER LOSSES FROM WET AREAS 53 althoug'li sufficient data were collected to obtain monthly totals through- out the following spring. Some weekly totals were omitted. Because of changes in depths to water tables in October, 1930, true records could not be obtained pending soil moisture adjustments and data for these periods are not included. At other times accident or failure of the Mariotte tanks to function properly is responsible for omissions. A complete summary of all work done at the Santa Ana station for each of the three years of the investigation is given in Tables 13, 14 and 15, which show the monthly use of water by all soil and water tanks. Descriptions of contents of tanks are included, and percentages of use of water by each moist area growtli with reference to evaporation from water surfaces is likewise tabulated. These data are the most valuable of the report. Use of Water by Bermuda Grass Bermuda grass {Cynodon dactylon) is a perennial with long, creep- ing, jointed stems, often several feet in length. It spreads largely by rooting at the nodes, although it also seeds abundantly. Where condi- tions are favorable it forms a dense turf, frequently becoming a pest in lawns by driving out or smothering other laAvn grass. It is found groov- ing wild in many localities, always in exposed places, as it is intolerant of shade. Bermuda grass is not an indicator of ground water, as is salt grass, although the experiments indicate that it may use slightly more water than salt grass when it is available. It is frequently used for pasture and makes good feed for stock. Excellent conditions for experimenting with Bermuda grass were found at the San Bernardino station. The yard in which the tanks were set was covered with a dense growth of the grass, so that tests of consumptive use of water were made with tank crops surrounded by a natural growth of the same variety. The principal difference between tank and field conditions was in depth to water table. In the tanks, the water table was fixed at definite levels during the three years of record, while the outside ground water fluctuated between 2^ and 6 feet below the ground surface. Data on weekly use of water by Bermuda grass grown in tanks at San Bernardino are given in Tables 16 and 17. In November, 1931, daily readings at the station were discontinued, because of high ground water entering the tanks through the waste pipes and changing the water levels. Records of weekly and monthly use of water immediately before and after the first week in October, 1930, are not comparable as at this time the grass was maliciously burned off from all four tanks. Previous to the burning, each tank had a heavy crop of grass which used over \ acre-inch of water per week. Immediately after the burn- ing, this loss was reduced over one-half. As the burning was done in the fall, no recovery was possible until the following spring when new growth a])i)eared on all tanks. In spite of the loss of grass, there was a small but continuous loss of water from each tank throughout the winter months. Plate VI shows the appearance of the grass in the tanks and in the surrounding field before burning took place. Tank growth is showni in the center of the picture as being higher than the surrounding grass. 54 DIVISION OF WATER RESOURCES TABLE 16 RECORD OF WEEKLY USE OF WATER BY BERMUDA GRASS IN TANKS AT SAN BERNAR- DINO, CALIFORNIA, MAY, 1929, TO SEPTEMBER, 1930i Week ending 192»- May 14 May 21 May 28 June 4 June 11 June 18 June 25 July 2 July 9 July 16 July 23 July 30 Aug. 6 Aug. 13 Aug. 20 Aug. 27 Sept. 3 Sept. 10 Sept. 17 Sept. 24 Oct. 1 Oct. 8 Oct. 15 Oct. 22 Oct. 29 Nov. 5 Nov. 12 Nov. 19 Nov. 26 Dec. 3 Dec. 10 Dec. 17 Dec. 24 Dec. 31 Use of water by Bermuda grass, in acre-inches per acre Fixed water table three feet below ground surface Tank No. 1 Tank No. 2 1.155 1 006 .828 1.198 .879 .828 1.558 1.389 1.187 1.175 1.497 1.137 1.490 1.121 1.212 1.098 1.118 .688 .742 .508 .582 .656 .901 .542 .466 .406 .400 .264 .232 .074 .149 .200 .205 .167 Mean Note: — Records for tank No. 2 could not be relied upon before October. 0.942 .403 .762 .902 .540 .382 .365 .261 .126 .286 .127 .201 .084 0.799 .652 .652 .684 .473 .391 .315 .246 .100 .217 .164 .203 .125 Fixed water table two feet below ground surface Tank No. 3 1.293 1.112 1.081 1.621 1.292 1.070 1.993 1.653 1.537 1.622 1.823 1.315 1.631 1.601 1.495 1.494 1 548 .837 1.219 .520 .636 .912 .667 .594 .772 .317 .498 .424 .327 .212 .266 .212 .201 .201 Tank No. 4 1 325 .964 .869 1.072 .859 .921 1.451 1.336 1.314 1.356 1.655 .964 1.388 1.304 1.281 1.273 1.177 .869 .911 .497 .636 .742 .645 .583 .593 .286 .392 .372 .349 .128 .255 .137 .233 .181 Mean 1.309 1 038 .975 1.347 1.075 .996 1.722 1.495 1.425 1.489 1.739 1.140 1.510 1.452 1.388 1.383 1.362 .853 1.065 .508 .636 .827 .656 .588 .683 .301 .445 .398 .338 .170 .260 .175 .217 .191 WATER LOSSES FROM WET AREAS 55 TABLE 16— Continued RECORD OF WEEKLY USE OF WATER BY BERMUDA GRASS IN TANKS AT SAN BERNAR- DINO, CALIFORNIA, MAY, 1929, TO SEPTEMBER, 1930' Week ending 1930- Jan. 7 Jan. 14 Jan. 21 Jan. 28 Feb. 4 Feb. 11 Feb. 18 Feb. 25 Mar. 4 Mar. 11 Mar. 18 Mar. 25 April 1 April 8 April 15 April 22 .\pril29 Mav 6 Mav 13 May 20 May 27 June 3 June 10 June 17 June 24 July 1 July 8 Julv 15 July 22 July 29 Aug. 5 Aug. 12 Aug. 19 Aug. 26 Sept. 2 Sept. 9 Sept. 16 Sept. 23 Sept. 30 Use of water by Bermuda grass, in acre-inches per acre Fixed water table three feet below ground surface Tank No. 1 Tank No. 2 .105 .139 .202 .160 .044 .063 .138 .265 .298 .373 .285 .180 .213 .211 .466 .571 .774 .287 .362 .448 .648 .741 1.258 .625 .953 1.256 1.186 .816 1.452 1.217 .573 .689 .974 .994 .890 .678 .783 .468 .403 .222 .188 .190 .148 .180 .074 .222 .232 .264 .264 .106 .105 .329 .201 .159 .688 .624 .370 .370 .338 .830 .870 .965 .955 .995 1.312 1.334 1.441 1.558 1.112 1.483 .858 1.007 .531 .890 Mean .169 .163 .186 .154 .112 .068 .180 .249 .281 .318 .196 .143 .271 .206 .312 .630 .699 .329 .366 .393 .739 .806 1.112 .790 .974 1,284 1.260 1.129 1.505 1.165 1.187 .768 .895 .500 .647 Fixed water table two feet below ground surface Tank No. 3 Tank No. 4 .148 .190 .127 .010 .064 .147 .212 .276 .181 .201 .074 .116 .614 .561 .657 1 039 .785 .296 .255 .627 1.058 1.167 1 345 1.175 1.219 1.515 1.399 1.633 1.578 1.496 1.409 1.093 1.146 1.473 1.249 1.145 .775 .753 .498 .179 .116 .106 .032 .042 .106 .125 .297 .233 .265 .191 .222 !l91 .223 .381 .901 .773 .626 .317 .339 .794 .933 1.271 1.208 1.166 1.484 1.271 1.398 1 452 1.346 1.071 1.123 .933 1.408 1.167 .985 .826 .561 .689 Mean .164 .153 .117 .021 .053 .126 .168 .287 .212 .233 .132 .169 .402 .392 .519 .970 .779 .461 .286 .483 .926 1.050 1.308 1.192 1.193 1.500 1.335 1.516 1.515 1.421 1.240 1.108 1.040 1.441 1.208 1.065 .801 .657 .594 ' All tanks covered during rains. Tanks contain undisturbed soil. 56 DIVISION OF WATER RESOURCES TABLE 17 RECORD OF WEEKLY USE OF WATER BY BERMUDA GRASS IN TANKS AT SAN BERNARDINO, CALIFORNIA, OCTOBER, 1930, TO NOVEMBER, 1931' Week ending 1930- ^Oct. 7 Oct 14 - Oct. 21 . Oct. 28 Nov. 4 .. Nov 11 ' Nov. 18 Nov, 25 , Dec. 2 Dec. 9 Dec. 16--, Dec. 23 Dec. 30--.- — 1 1931— Jan. 6- Jan. 13- Jan. 20- Jan. 27- Feb. 3- Feb. 10- Feb. 17- Feb. 24- Mar. 3- Mar. 10- Mar. 17- Mar. 24. Mar. 31- April 7- April 14- April21_ April 28- May 5- May 12- May 19- May 26- June 2- June 9- June 16- June 23- June 30- July 7- July 14- July 21- July 28- Aug. 4- Aug. 11- Aug. 18- Aug. 25. Sept. 1- Sept. 8- Sept. 15- Sept. 22. Sept. 29. Oct. 6- Oct. 13- Oct. 20- Oct. 27. Nov. 3. Nov. 10- Use of water by Bermuda grass, in acre-inches per acre Fixed water table three feet below ground surface Tank No. 1 Tank No. 2 0 319 .137 .105 .096 .169 .126 .083 .116 .137 .116 .095 .084 .148 .021 .042 .043 .042 .021 .159 .148 .264 .274 .231 .392 .562 .435 .519 .317 .382 .795 1.145 .966 .816 1.420 1.281 .996 .858 .858 1.144 .658 .404 .563 .806 .731 .487 .424 .371 .435 .200 .306 0.297 .168 .212 .127 .276 .244 .294 .274 .169 .181 .148 .116 .073 .011 .042 .117 .126 .095 .382 .720 .668 .480 .414 .499 .762 .743 .605 797 .786 .817 1.389 1.409 1.633 1.410 1.335 1.304 1.336 .594 1.155 .858 .562 .679 .655 .445 .508 .615 .522 .233 .212 Mean D 308 .153 .159 .112 .223 .185 .189 .195 .153 .149 .122 .100 .111 .016 .042 .080 .084 .058 .271 .434 .466 .377 .323 .446 .662 .589 .562 .557 .584 .806 1 267 1.188 1.225 1.415 1.308 1.150 1,097 .726 1.150 .758 .483 .621 .731 .588 .498 .520 .447 .217 .259 Fixed water table two feet below ground surface Tank No. 3 Tank No. 4 0.457 222 ^233 .340 .340 .413 .202 .255 .074 .170 .169 .147 .105 .043 .052 .147 .147 .212 .402 .403 .563 .562 .689 .836 .911 .222 .412 .985 .049 .860 .689 .615 .763 377 749 527 674 876 1.666 1.568 .420 .144 .419 .849 .625 .155 .836 .721 .594 .583 .476 .392 .742 .297 0.276 .371 .294 .224 .244 .244 .202 .190 .127 .126 .116 .116 .136 .042 .053 .021 .063 .138 .307 .328 .509 .434 .488 .836 .837 .254 .360 .710 .934 .711 .773 .456 .679 .293 1.516 1.409 1.687 1.538 1 345 1 322 1.239 .678 1.442 .605 .551 .859 .784 .752 .666 .266 .253 .541 .425 Mean 0.367 .297 .264 .282 .292 .329 .202 .223 .101 .148 .143 .132 .121 .043 .053 .084 .105 .175 .355 .366 .536 .498 .589 .836 .874 .238 .386 .848 .992 .786 .731 .536 .721 1 335 1.633 1.468 1.681 1.707 1 506 1.445 1.330 .911 1.431 .727 .588 1.007 .810 .737 .630 .371 .323 .642 .361 • All tanks covered during rains. ' Grass burned off tanks. Tanks contain undisturbed soil. WATER LOSSES FROM WET AREAS 57 Plate A'll sliOAvs a comparison of the consumptive use of water by Bermuda grass and salt grass, and also evaporation from the water surface of a ground tank of the same size as the soil tanks. The ground tank was No. 16 at the Santa Ana station. The water table in each case was 2 feet in depth during the period indicated, and the results PLATE VI ietk ■■■« W- BERMUDA GRASS IN TANKS IN FIELD OF SIMILAR GROWTH AT SAN BERNARDINO. THE TANKS ARE IN THE CENTER OF THE PICTURE SHOWING HEAVIER GROWTH. given are the averages of three tanks of salt grass and of two tanks of Bermuda grass. respectiA^ely. During the period of record the total use of water by salt gra.ss was 29.6 acre-inches per acre, while that by Bermuda grass was 34.7 acre-inches per acre. Although consumptive use by Bermuda grass is the greater, the maximum 12-month record from ]May to April during the three years of measurement was but little more than 3 acre-feet per acre in a year 58 DIVISION OF WATER RESOURCES when the tanks were protected from rainfall. If there had been no protection consumptive use would have been slightly increased. The San Bernardino district has an interior climate which increases evapora- tion and consumptive use of water to an amount greater than that in the coastal climate of Orange County, and irrigation requirements also are higher. The use of water by Bermuda grass is probably somewhat higher than the use by citrus, but less than that by alfalfa. Bermuda grass, therefore, does not make an excessive demand upon the ground water supply. Monthly consumptive use of water by Bermuda grass for the period covered by the investigation is shown in Tables 18, 19 and 20. These tables also show the total use of water for each year, ending April 30. Some months are omitted, but percentages of use for the PLATE VII vap I Ai pa/7 Bernardino (Bermuda) " At Santa /}na (Salt Grass) I. from ground iank >. 16 a/ San fa ^na 5 Apr. : I May- iJune.lJuly. ^ ^- \ Aug. R < Sept. Oct. Nov. Dec. 1931 COMPARISON OF USE OF WATER BY BERMUDA GRASS AT SAN BERNARDINO WITH THAT OF SALT GRASS AT SANTA ANA AND EVAPORATION FROM WATER IN TANK NO. 16 AT SANTA ANA. months of record, based on the evaporation from both the circular sunken evaporation tank and the Weather Bureau pan, separately, are given for the same period. It is through these percentages that com- parisons of consumptive use with the same or different crops grown under different climatic conditions may be made. Use of Water by Tules and Cat-Tails A study of consumptive use of water by aquatic growth was begun in the summer of 1929 at the Santa Ana station by transplanting rooted plants of round stem tules into a single tank. In the following spring investigation of triangular stem tules and cat-tails was begun at Santa Ana and later one tank of triangular stem tules at Prado and one tank of round stem tules at San Bernardino were included. The round stem tule or common bulrush (Scirpus acutus) is a perennial plant with a round, dark green stem which grows to a height of 6 to 12 feet. It is found in abundance in some sections where water VCES, MAY, 1929, TO APRIL, Number of months of record Total amount used Per cent of ;iary March April Tank No. 5 Tank No. 7 1 647 V676 1.662 '742 ^.676 1.709 1 .676 1 136 .877 1.006 1.122 .975 1 048 3.912 2 139 1.798 1.968 3.063 2.373 2 718 5.400 12 6 12 12 12 12 2 12 32.526 51.2 45 5 37 266 63 572 13 858 71 490 58.6 100.0 105 3 112 5 52.1 88.9 95 6 '456 5 016 5.376 100.0 IR SI JRFACES , MAY, 1< )30, TO Number of months of record Total amount used Per cent of nary March April Tank No. 5 Tank No. 7 1 .495 .211 .353 .253 (•) .058 0.169 .391 .280 2.036 1.674 , 1.855 4 953 8 883 5 766 9 9 10 11 11 11 12 11 12 '2 2.334 2 334 2.700 2.457 2.579 4 064 13 399 4-892 I 3 23 833 49 3 43.0 4 5 6 7 31 010 53 396 170 880 61.594 61 3 100.0 334.1 115 4 53.0 86 7 291.9 100 0 TABLE 18 SUMMARY SHOWING MONTHLY USE OF WATER BY BERMUDA GRASS AND EVAPORATION FROM WATER SURFACES, MAY, 1929, TO APRIL, 1930, IN TANKS AT SAN BERNARDINO, CALIFORNIA' Tank No. Content of tank Depth to water table, in feet Diameter of tank, in inches Amount of water used, in inches of depth Number of months of record Total amount used Per cent of Ma>-= June July August September October November December January February March April Tank No. 5 Tank No. 7 1 3 3 3 2 2 2 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/18 23 1/16 48 4 280 5 216 5 489 S 345 2 901 2,771 1 255 1 505 1 380 1 641 1 410 1 525 4 704 ' 4 980 0 719 .761 .740 1 007 849 928 3 480 s'sie" 0 650 886 ,768 ,475 433 454 2 220 "2 316 0 647 676 B62 742 876 709 2 676 3 456" 1.136 .877 1,006 1 122 ,975 I 048 3,912 5 016' 2,139 1,798 1,968 3,063 2,373 2 718 5,400 12 6 2 Mean 32.526 51 2 4.280 5 340 4 840 5,090 6,090 5 216 6 348 4 854 5,601 7.596 5 489 7 144 5 872 6 508 8 892 5 345 6 804 5 660 6 232 7 740 8 296 8 808 2 901 3 785 3 337 3 561 5 426 5 562 5 690 2,771 3 061 2 722 2 892 5 436 5 580 3 12 12 12 12 2 12 4 37 266 63 672 13 858 71 490 58.6 100 0 105 3 112 5 52 1 88.9 95.6 100 0 6 7 Water in standard Weather Bureau pan 7.780 8.892 9 780 ' Tanks contained undisturbed soil. All grass tanks covered during rains. ^Records began May 8. 1929. but May totals are proportioned for full month. TABLE 19 SUMMARY SHOWING MONTHLY' USE OF WATER BY BERMUDA GRASS AND TULES AND EVAPORATION FROM WATER SURFACES, MAY, 1930, TO APRIL, 1931, IN TANKS AT SAN BERNARDINO, CALIFORNIA' ' Tank No. Content of tank Depth to water table, in feet Diameter of tank, in inches Amount of water used, in inches of depth Number of months of record Total amount used Per cent of May June July August September October' November December January February March April Tank No. 5 Tank No. 7 1 Bermuda grass. _. 3 3 3 2 2 2 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 48 2.031 2 163 2.097 2.916 2 500 2.708 4 572 16 935 5 496 4 552 4.524 4.538 5.560 5.235 5 393 5 976 22.125 6 588 4 872 5 997 5 435 6.710 8 135 8 423 8 804 30 052 8 078 3,898 2 533 3,625 3,079 3 520 3 358 3 439 5,124 17.417 6 472 0 720 .963 .842 1 337 1 261 1 299 4,860 '13,989 5 208 0 626 1 034 ,780 1 188 ,890 1 039 3 506 '12 860 3 788 0 506 593 550 ,623 .547 585 2 851 '5 365 2 634 0 169 .391 ,280 2 036 1,674 , 1,855 4 953 8 883 5 788 9 9 10 11 11 11 12 11 12 2 . 0 495 211 353 2 253 (•) 3 058 2 334 2,334 2,700 2 457 2 579 4 064 13 399 4 892 23 833 49 3 Mean Bermudagrass 3 898 5 608 5 066 5 337 6,844 26,108 7 536 43 0 3 Bermuda grass 4 Bermudagrass Mean Bermudagrass. 31 010 53 396 170 880 81 594 61 3 100 0 334 1 115 4 63 0 6 2 789 4.047 3 100 86 7 6 291 9 7 . . Water in standard Weather Bureau pan .... 100 0 ' Tanks contained undisturbed soil. *Grass burned off Tanks Nos. 1 to 4, October 4, 1930. » Use for November computed from 21-day record. * Ijse for December computed from 20-day record. ^Use for January computed from 25-day record. •Heavy rains ruined record. '.411 grass tanks covered during rains. •Not applicable to field conditions. 4503 — Bet pp. 58-59 TABLE 20 SUMMARY SHOWING MONTHLY USE OF WATER BY BERMUDA GRASS AND TULES AND EVAPORATION FROM WATER SURFACES, MAY, 1931, TO APRIL, 1932, IN TANKS AT SAN BERNARDINO, CALIFORNIA' ' Tank No. CoDtent of tank Depth to water table, iu feet Diameter of tank, in inches Amount of water used, in inches of depth Number of months of record Total amount used Per cent of May June July August September October November December January February March ('1 April Tank No. 5 Tank No. 7 1 3 3 3 2 2 2 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 23 1/16 48 1 959 2 759 2.359 3 677 3 086 3 382 4 850 18 067 6,794 2.798 3,969 3 384 4 780 4 304 4 .542 5.734 21 705 7 384 6 002 6 168 5.585 7 474 6 646 7 060 6 727 29 250 8 918 3 931 4.813 4 372 5 595 4 566 5 081 fi 886 23 233 8 062 2.653 2 465 2 559 3 528 3,306 3,417 5,448 '12,876 5,808 1 759 1 919 1,839 2 332 2 456 2 204 2,330 2 425 2 523 2 474 2,674 5 381 3 482 1,886 .757 1 322 2 057 1,854 1 986 2,786 5 050 2 098 1.129 9 8 9 9 8 9 12 11 12 2 . Mean Bermuda grass Bermuda grass Bermuda grass Bermuda grass 1.129 1 540 1 573 1 557 3 008 4 151 3.126 24 879 58 3 49 3 3_ 4 2 332 4 596 7 575 4 812 31 801 54 933 141 922 65 134 74 5 100 0 272,7 118,6 63 0 5 2,892 '3 134 4 232 5 839 5,240 5 100 8 795 6 276 84 3 6_ 228 9 7.- 100.0 ' Tanks contained undisturbed soil. ' All grass tanks covered during rains prior to December 1, 1931. *Tules eaten off by stock in September. * Hea\'j' rains ruined record for Bermuda grass tanks. ' Not applicable to field conditions. 4503— Bet. pp. 58-59 WATER LOSSES FRO:\r WET AREAS 59 is plentiful and grows with its roots submerged in the shallow water along the edges of stream channels and in swamps. It is a great nuisance in drainage ditches. The triangular stem tule (Scirpus olncyi) is similar to the round stem variety, being an aquatic plant that grows in areas of shallow water. The stems are three cornered and grow with considerable density, but are not generally as tall as the round stem tules. The cat-tail {Typha lati folia) is a perennial marsh plant with flat leaves that is frequently classed as a tule, although it belongs to an entirely different family. Its cylindrical head is filled with thousands of small cottony seeds which are spread by the wind. The cat-tail is found wherever there is sluggish water. It spreads rapidly from seed and is hard to eradicate. Both tules and cat-tails were grown in tanks set in the ground with 2 inches of rim surface exposed. Water was held on the tank surface to a depth of approximately 2 inches so that the roots were entirely submerged. It seems probable that air is supplied to the root systems of growths of this type through the coarse cellular structure of the stems. The surrounding ground surface w^as free from vegeta- tion during the first season, but later was covered with grass. All tule or cat-tail tanks were in exposed locations, subject to the full effect of solar radiation and wind movement. In this respect, tules grown at the stations differed from tules in swamps where a certain degree of protection is afforded by increased vegetation and a larger growing area. Consumptive use by swamp growth is partly controlled by greater humidity overlying the swamp area. It is probably true, too, that temperatures within the swamp are lower than those outside. Both factors would combine to cause a lower use of water by swamp plants than by those in exposed tanks. In general, it appears that aquatic plants in exposed tanks do not attain the maximum height of stalk growth that is found under natural conditions. Tank growth rarely exceeds 5 or 6 feet in height when fully exposed, and more often is less, whereas natural swamp growth of tules or cat-tails frequently grow to a height of 10 or 12 feet. The highest growth occurs in the swamp interior, with shortej' stalks around the water's edge. In this respect the outside growth in a swamp is com- parable to that in experimental tanks. To determine whether size of tank had an effect on consumptive use of water, an additional tank, 6 feet in diameter, was transplanted to round stem tules at the Santa Ana station. The density of growth at no time equalled that in the smaller tank and the consumptive use per unit of area was consequently less. A comparison of the data obtained from two tanks for tlie month of September, 1931, shows that the smaller tank had a density of 87 stems per square foot of tank area, which used water at the rate of 19.37 acre-inches per acre per month, M-hilo the larger tank had only 57 stems per square foot of area using 12.43 acre-inches. The exposure of both tanks was identical. Carrying the comparison further to determine the consumptive use per individual stalk indicates that each tule used tlie same amount of water, regardless of density of growth or size of tank in which it grew. Plate VIII-A shows the 6-foot tule tank, No. 23, with the small tule tank. No. 19, at the right. 60 DIVISION OP WATER RESOURCES PLATE VIII if* 1 ( A^ It, •^, i,0>C S Q »<..^ 4 ^l:, A. TULES GROWING IN TANK SIX FEET IN DIAMETER AT SANTA ANA STATION, 1931, WITH SMALL TANKS OF TULES AND CAT-TAILS AT THE RIGHT. Hi' ir'i.-»i ;.i^ B. CAT-TAILS GROWING IN SMALL TANK, SANTA ANA STATION, 1931. C. TULES GROWING IN SMALL TANK, PRADO STATION, 1931, WATER LOSSES FROM WET AREAS 61 The cooperative station at Prado was intended principally to deter- mine the rate of use of water by tales in connection with a study of the flow of the Santa Ana Kiver that was being made by the United States Geological Survey. As the station was isolated and daily visits were not practicable, recording devices were attached to both tule tank and Weather Bureau evaporation pan. From the records so obtained the hourly rates of consumptive use and of evaporation have been computed. These are plotted in Plate IX, which shows air and water temperatures, consumptive use of water by tules in an isolated tank, and evaporation from a four-foot pan for each hour of the day from August 21 to August 28, 1931, inclusive. There were periods during the early morning hours when the loss of w^ater was too small to be recorded and evaporation or transpiration, during those hours, has been listed as zero. Characteristic of both evaporation and transpiration is the daily increase or decrease with a rising or falling temperature. The minimum rate occurs near sunrise and the maximum is in the after- noon. Consumptive use is greater than evaporation and responds more readily to sunlight and changes of temperature. The rate of evapora- tion does not increase rapidly until water in the pan has been warmed PLATE IX HOURLY RATE OF USE OF WATER BY TULES, EVAPORATION FROM STANDARD WEATHER BUREAU PAN AND AIR AND WATER TEMPERATURES, PRADO STATION. by the sun and is relatively slow in comparison with the rate of con- sumptive use, which increases rapidly, comes to a peak sooner, and declines more quickly. On the morning of August 28 temperature was less than normal and a light rain occurred shortly after noon. The effect of the rain in deferring the morning increase in consumptive use and in evaporation from water until about 2 p.m. is shown on the chart. The rain was apparently the cause of a small decrease in the rate of evaporation until its effect was overcome by a rise in temperature. In general, the highest air temperature occurred at about 1 or 2 p.m., while the highest water temperature occurred about two hours later. The same interval also is noticeable in minimum temperatures. Observations in other localities have shown that the highest consumptive use of water by tules 62 DIVISION OF WATER RESOURCES occurs at approximately the time of highest air temperatures, although such is not the case in this instance. Coastal Avinds continuing through several hours each day pass over the Prado station and, in combination with high temperatures, are responsible for a continued increase in both evaporation and transpira- tion until 3 or 4 o'clock in the afternoon. This accounts for a larger consumptive use than at other localities in the Santa Ana basin. Because of their exposure and abnormal conditions affecting growth, use of water by tules grown in tanks was excessive. At Santa Ana station, round stem tules used more water than did the triangular stem tules or the cat-tails, their gro-\\i;h being greater in point of density and height of stems. Their consumptive use frequently amounted to more than 1| inches in depth per day and at one time averaged an inch a day for a period of six weeks. Tules at the Prado station had a higher consumptive use than did those of the same A-ariety at Santa Ana, partly because of slight climatic differences, but also because of differences in height and number of stems. The maximum daily use at Prado was 3.6 acre-inches per acre on a day of high temperature and wind movement. Intensive investigations near Victorsdlle, undertaken to determine the proper adjustment factor to be used in reducing consumptive use of water by tules groAvn in tanks to the actual amount used by swamps, are discussed in the folloAAdng chapter. In this study, one 2-foot tank containing tules Avas fully exposed to Avind and sunshine Avith a result- ing large use of Avater. A large tank set in a protected area of a SAvamp used a much smaller amount. Further investigation by the Bureau of Agricultural Engineering in the Sacramento-San Joaquin delta indi- cates a factor of 0.46 for cat-tails and tules for a 20-day period in August, 1930. Reporting on this and other Avork, Charles H. Lee* has adopted a tentative factor of 0.50 for making the reduction, admitting that the value may be changed Avhen further data are available. By applying the results of the Victorville investigation to the measured losses from isolated tanks used in southern California, it is found that the adjustment factor ranges in these experiments from 0.29 to 0.55 as shoAvn in Table 21. AYliile the relation betAveen the Avater requirement of a crop and evaporation from a Avater surface during the groAving season is not constant, month by month, it is the most practical means of making comparisons of consumptive use, not only from year to j'ear, but between localities having different rates of evaporation. For this purpose the best records for comparison are those of standard Weather Bureau eA^aporation pans, which are in more general use in investigational Avork than pans of other sizes or depths. For the Victorville station, where tules were grown in a swamp area, the percentage of consumptive use in the swamp with reference to CA^aporation from the "Weather Bureau pan is computed for an average year, the result being about 95 per cent. In the average year the consumptive use for each month is taken as the average of all records for that month. Neglecting other factors, such as variety, density of groAvth, and seasonal variations in evaporation and transpiration, this percentage has been applied to evaporation * BuUetin No. 28, Economic Aspects of a Salt AA'ater Barrier Below Confluence of Sacramento and San Joaquin Rivers, Division of Water Resources, 1931. WATER liOSSES FROM WET AREAS 63 records at Santa Ana, i'rado, and San Bernardino. In other words, 95 per cent of the evaporation at a station is estimated to be the con- sumptive use of water by aquatic growth in a natural swamp area in tliat locality. Ilaviuir computed the estimated consumptive use in a swamp, the percentage of computed swamp use to the observed tank use, mav be determined. This was the method followed in compiling Table 2i. TABLE 21 ESTIMATED CONSUMPTIVE USE OF WATER BY TULES AND CAT-TAILS IN SWAMPS BASED UPON TANK EXPERIMENTS, AND PERCENTAGE OF SWAMP USE TO TANK USE Station Tank number Aquatic growth Observed consumptive use from exposed tank, in acre-inches per acre per year Evaporation from Weather Bureau pan, in inches per year Computed consumptive use from swamp, in acre-inches per acre per year Swamp consumptive use, in per cent of observed consumptive use Victorville . Triangular stem tules- _ Round stem tules TriangTilar stem tules. . Cat-tails 272.2 188.3 172.5 116.9 115.4 251.3 162.1 '82.5 66.6 66.6 66.6 66.6 77.4 66.1 '78.5 63 4 63.4 63.4 63.4 73.6 62.9 28.8 19 21 22 23 33 7 Santa Ana Santa Ana 36 8 54 2 Santa Ana Round stem tules Triangular stem tiiles- - Round stem tules 55.0 Prado 29.3 San Bernardino 6 38.8 Mean percentage . 39.5 ' The observed swamp consumptive use at Victorville is 95.2 per cent of the evaporation from the Weather Bureau pan. This percentage multiplied by the evaporation at each station equals the computed swamp use for that locality. In the last column of the table there is a large difference in per- centages. These are due in part to differences in density of gro^^i:h in each tank. Disregarding small dift'erences in rates of transpira- tion, which may exist in different varieties of aquatic growth, the total use of water by adjacent tanks should correspond rather closely, pro- vided that the dry weight of crop matter is nearly the same. Trans- piration is nearly proportional to the transpiring area and is conse- quently more where there is a heavy growth than where the growth is light. Each tank used had different density of growth and a different consumptive use. In Tank No. 22 cat-tails did not spread and produce as thick a growth as is natural in .swamp areas, nor did they reach the height of stems found in swamps. The same is true of round stem tules in Tank No. 23. In both cases, the observed consumptive use is less than that of triangular stem tules at Santa Ana or of round stem tules at San Bernardino, and the percentage of computed swamp use to observed tank use is much higher than the average for other tanks. Likewise, consumptive use by tules at Prado is high and its relation to swamp use is correspondingly low. The results of the tule tank experiments indicate the impractica- bility of applying to field conditions records of tests made in isolated tanks of tules grown apart from their natural environment. 64 DIVISION OF WATER RESOURCES Use of Water by Willows Willows are water-loving shrubs or trees found in areas of com- paratively high ground water. They often grow in the coarse material forming di'y stream channels, where they draw moisture from the underflow. The root system of some varieties includes a long tap root which enables the plant to receive moisture from a water table at a considerable depth. Willows have been observed in a very sandy soil where depth to water table was about 10 feet. Investigation of consumptive use of water by a single willow {Salix laevigata) bush was begun at the Santa Ana station in 1930. The bush consisted of a single clump of 20 stems from one-half to an inch and one- quarter in diameter growing from the same root. The average height was about 7 feet. This bush was transplanted into a metal tank, 6 feet in diameter hy 3 feet deep. Measurement of consumptive use was begun in May, 1930, and continued for two years. The spread of bush area was the same as the tank area and consumptive use was computed on that basis. The soil in the tank was bare, consequently the total use includes soil evaporation. Water in the soil stood 2 feet below the surface. As the soil in the tank was shaded by the willow growth and grass and weeds grew up around the tank, evaporation was probably no more than occurs under ordinarj^ conditions of scattered brush growth. Previous experiments with evaporation from disturbed soil having the same water table depth show losses ranging from less than 1 to nearly 3 inches per month, depending upon the season. Evaporation from the willow tank should be relative^ small on account of shade and protection due to overhanging branches. During both years of the investigation stems and leaves of the willow were heavily infested with aphis and the red ants that are found with them. During 1930 the tree was sprayed regularly, every effort being made to control the pest, and apparently no harm was done. In the following year, defoliation began early in the summer and was com- plete by September, several weeks earlier than is normal. During this period consumptive use records are not for a healthy tree in full leaf. In the following spring of 1932, the third of the investigation, a normal growth of new leaves appeared at the regular time, indicating that no permanent damage to the tree had occurred. Plate X shows the Avillow growing in a 6-foot tank at Santa Ana in May, 1930, before vegetative growth surrounded the tank. Soil in the willow tank originally contained some alkali. During the summer months, when evaporation was at a maximum, white alkali was deposited on the tank surface. As the daily amount of water was added to the tank the total amount of alkali increased. These salts went through seasonal changes in location in alternate wet and dry seasons as they were carried down to the water table by winter rains and returned to the surface by summer evaporation. During the period when the tree was losing its leaves alkali was visible on the tank surface, but apparently not to exceed the amount of the previous year when no defoliation occurred. The willow is normally a user of relatively pure water and does not grow where salts are found in high concentration. The defoliation may have been due either to presence of alkali or to infestation. WATER LOSSES FROM WET AREAS 65 Consiiniptive use of water by the willow groAvth by months is shown in Tables 14 and 15. The maximum monthly use in the year in which the growth was in good condition, amounting to 7.8 acre-inches per {'cre, occurred in August. In comparison with evaporation from a Weather Bureau pan, consumptive use exceeded evaporation only dur- ing the months of August and September. The total use during a period of eleven months, shown in Table 14. was 52.7 acre-inches per PLATE X WILLOW TREE GROWING IN 6-FOOT TANK, SANTA ANA STATION, 1931. acre or 83.5 per cent of the evaporation from a Weather Bureau pan for the same period. It is evident that willows grown in tanks under the conditions of this experiment, are fairly large users of ground water. The amounts used exceed consumptive u.se by either salt grass or Bermuda gra.ss, but are less than consumptive use by tules under natural swamp conditions. An adjustment factor has been computed for tules to adjust con- sumptive use of water by tank growth to similar growth in large areas, 5 — 4503 66 DIVISION OF WATER RESOURCES but no basis exists for computing the proper factor for use with willows. Because there is a great natural difference in the habits of growth of tules and willows, the same factor will not apply to both. Tules naturally grow in swamp areas, whereas willows are found in scattered areas of dry land, sometimes in isolated clumps, small groups, or in large bodies of ))rush. AVhere isolated growth occurs, conditions of temperature, sunlight, and wind movement are the same as for tank growth, and consumptive use is nearly the same in all cases. In dense grovrths of brush, however, conditions are changed to reduce the factors mentioned and transpiration also is less. In this case, an adjust- ment factor should be applied to the observed consumptive use by willoM'S grown in tanks to arrive at the correct figure for field con- ditions. In many instances willows grow as a fringe along water courses, and endjankments of ditches. They are also found in large areas interspersed with open places that are sometimes of considerable size. Considering differences in the spread of willow growth it is evi- dent that an adjustment factor is not a constant that can be used under all conditions, but is a variable depending upon density and size of brush. Due to the present lack of data, any factor arrived at must be only an estimate, subject to revision later when further evidence is available. For willow growth in the Santa Ana Kiver basin, which is ]iartly in solid blocks of brush and partly scattering, it is estimated that consumptive use is 75 to 100 per cent of the amount of water necessary for isolated tank growth, with an average of 85 per cent. Use of Water by Wire Rush Wire rush (Juncus hallicus) grows in limited areas of high ground water in the Prado basin where it is found in association with salt grass. In appearance it is a heavy, tough, Avire-like grass growing from a thick creeping rootstalk. In places where it was observed, it did not exceed 10 or 12 inches in height. Some of this growth was transplanted into a small tank at the Santa Ana station in the summer of 1930 for the pur- pose of making a consumptive use of water study, as indications were that it might be a large user of water. During the first year of the study a considerable amount of salt grass Avas included with the wire rush, but in the following year the heavier growth had croAvded out the salt grass. A fixed water level was maintained at a depth of 2 feet in the tank, although where a natural growth occurred in tlie fields there were seasonal fluctuations of ground water at greater depths. This depth was the same as that chosen for investigations of consumptive use by salt grass, Bermuda grass, and willows. During the first winter, the wire rush tank was protected from rainfall, as were all soil moisture tanks, but during the second year it was exposed to all rains. A summary showing monthly use of water b,y wire rush is given in Tables 14 and 15. The maximum use for any month was 13.75 acre- inches per acre during July, 1931. The total use for a ten-month period was 83.45 acre-inches per acre or 141.8 ])er cent of the evapora- tion from a Weather Bureau pan for the same period. In comparison with consumptive use by grasses and willows, the wire rush has appeared to be a heavy user of water and it is fortunate that the area restricted to its growth is limited. WATER T,OSSES FRO:\r WET AREAS 67 Adjustment Factors Previous tables have shown weekly' or monthl_y use of water by each oTowtli at tlie several stations, but Table 22 contains the observed average yeai'ly eonsumplive use and also an estimated factor for adjust- ment of such use to consumptive use over large areas. This factor for tules and cat-tails is based upon experiments carried on at Victorville and reported in Chapter III. No experiments have been made to deter- mine a factor for grasses, but conditions of tank growth are so nearly those of the tield, that factors for these crops have been taken as 100 per cent. A tentative factor of 85 per cent has been adoi)ted for willow as previously stated. TABLE 22 SUMMARY OF TANK INVESTIGATIONS SHOWING ESTIMATED ANNUAL CONSUMPTIVE USE OF WATER IN MOIST AREAS Type of vegetation Depth to water table, in feet Location Length of effective record, in months Observed average consumptive use, by vegetation in tanks, in acre-inches per acre per year Estimated factor for adjustment to large areas, in per cent Estimated annual depth of consumptive use, in acre-inches per acre per year 2 3 4 1 2 3 4 5 2 3 19 11 5 17 31 11 17 10 32 31 22 33 24 23 24 28 17 19 4.7 1.6 0.0 42.1 36 0 24.8 13 2 19.6 36,2 28.8 162 1 188.3 115.4 116.9 172 5 251.3 52.7 84.5 100 0 100.0 100.0 100 0 100 0 100.0 100.0 100 0 100.0 100.0 '38,8 '33.7 <55.0 '54. 2 '36.8 •29.3 85 0 4 7 Santa Ana ... 1 6 Santa Ana 0 0 Salt grass Santa Ana _ 42 1 Salt grass . Santa Ana 36 0 24 8 Santa Ana... 13.2 Salt grass Bermuda grass Bermuda grass Round stem tules _ Santa Ana San Bernardino San Bernardino San Bernardino 19.6 36.2 28.8 62 9 63.4 Santa Ana 63.4 Cat-tails Santa Ana 63 4 Triangular stem tules. Triangular stem tules. Willow Santa Ana 63.4 2 2 Prado ,. Santa Ana Santa Ana 73.6 47.8 Wire rush 1 Evaporation from surface of bare soil. 2 Tules grown in tank 251^ inches in diameter. ' Tules grown in tank 6 feet in diameter. 'See Table 21. No data are available for estimating an adjustment factor for wire rusli. While the tank in which it grew was not set in a field of similar groAAih, it Avas surrounded by grass and weeds. It is possible, since it did not grow in its natural habitat as did the salt grass, that change of environment was responsible for an increased consumptive use as is the ease with tules in isolated tanks. In Table 22 there are also presented estimates, based upon experi- ments, of the annual drafts upon the ground water by noneconomic native growths found in moist areas in the Santa Ana basin. These estimates are only for those depths to ground water at which the 68 DIVISION OF WATER RESOURCES experiments were conducted and are not applicable to other localities with markedly different climatic conditions. SOIL CHARACTERISTICS The top soil at the Santa Ana station was overlying a coarse water bearing sand at a depth of 6 to 7 feet. It contained considerable mica and some alkali in qnantities not detrimental to the varieties of vege- tation nsed in the investigation. A thin layer of finer than average material lay at a depth of about 4 feet in all Santa Ana tanks, a mechanical analysis of which showed that 29 per cent should be classed as very fine sand and 59 per cent as silt. This fine material was unim- portant, as in all tests except one it lay below the water table and could have no effect on capillary rise of moisture or rate of transpira- tion. In the one case referred to, where it was a few inches above the water table, it apparently had no influence on rate of movement of soil moisture. Soil at the San Bernardino station is classed as Chino silt loam and is relatively free from alkali. Mechanical Analyses Mechanical analyses of soil from five tanks at the Santa Ana station and from two tanks at the San Bernardino station were made, and the percentages of different sized soil particles are shown in Table 23. Each sample of soil, representing 1 foot in depth and weighing TABLE 23 MECHANICAL ANALYSES OF SOIL FROM TANKS AT SANTA ANA AND SAN BERNARDINO STATIONS Tank number Depth of sample, in feet Per cent of material retained on screens of the following s'zes No. 14 No. 28 No. 48 No. 100 No. 200 Per cent of material passing screen No. 200 SANTA ANA STATION 3 1 0 0 14 42 21 21 3 2 0 2 23 46 14 15 3 3 0 1 17 39 21 22 3 4 0 2 13 49 16 20 5 1 0 2 22 43 15 18 5 2 0 1 13 45 19 22 5 3 0 1 12 36 20 31 7 1 0 2 17 42 16 23 7 2 0 1 16 42 18 23 7 3 0 1 14 42 16 27 12 1 0 2 13 35 20 30 12 2 0 1 1(1 33 21 29 12 3 0 1 18 32 19 30 12 4 0 1 17 47 13 22 12 5 0 3 13 51 20 13 12 6 1 12 45 22 4 10 15 1 0 4 20 47 14 15 15 2 0 2 18 44 18 18 15 3 0 2 16 46 19 17 2 1 2 2 2 3 4 1 4 . 2 SAN BERNARDINO STATION 0 2 16 28 13 41 0 2 21 23 13 41 1 4 18 38 13 26 0 1 29 30 14 26 0 1 20 29 19 31 WATER LOSSES FROM WET AREAS 69 TABLE 24 MOISTURE EQUIVALENTS OF SOIL FROM TANKS AT SANTA ANA AND SAN BERNARDINO STATIONS Tank Depth of sample, Moisture equiv- Tank Depth of .sample, Moisture equiv- number in feet alent in per cent number in feet alent, in per cent SANTA ANA STATION SANTA ANA STATION 1 1 5.8 11 1 10.4 2 8.1 2 11.0 3 8.7 3 12.2 4 6.2 4 11.9 2 1 6 5 12 1 11.0 2 8.2 2 13.0 3 9.4 3 12.3 4 7.8 4 12.2 3 1 6.6 '13 1 6.3 2 7.1 2 6.2 3 9.2 4 8.9 '14 1 2 6.2 6.7 4 1 7.0 2 8.3 '15 1 2 6.5 6.6 5 1 8.3 2 9.0 SAN BERNARDINO STATION 6 1 8.7 1 1 30.6 2 8.4 2 3 19.7 15.2 7 1 8.6 2 9 0 2 1 2 31.2 21.4 8 1 2 10.3 9.8 3 16.3 3 1 29.4 9 1 2 11.4 11.7 2 19.8 4 1 28.6 10 1 2 3 4 9.9 12.6 12.0 9.4 2 19.3 ' Tank Nos. 13, 14 and 15 contained disturbed soil, all others contained soil in place. about 1000 gTams, was air dried and screened to the point of refusal. Results at Santa Ana show that about 40 per cent of the sample was retained on a No. 100 screen and nearly half that amount passed the No. 200 screen. Soil at the San Bernardino station was finer and a larger per- centage passed the No. 200 screen. Moisture Equivalent Moisture equivalent is a measure of the value of the moisture retentiveness of a soil and is obtained by subjecting a sample of 80 grams to a constant centrifugal force of 1000 times the force of gravity for a period of 30 minutes. Experiments by many investigators have determined that moisture equivalent is a close measure of the field capacity. Tt is more easily interpreted as regards soil moisture reten- tion than is possible by sej)aration of soil particles into groups as determined by mechanical analysis. Colloidal matter in the soil, as an important factor in affecting specific yield or s])ecific retention, is not apparent in determinations of mechanical analysis, but does affect the percentage of moisture retained. High moisture equivalents are obtained from fine grained soils containing quantities of colloidal 70 DIVISION OF NYATER RESOURCES matter, while low values come from coarse materials of low water holding capacity. Soil moisture samples at the Santa Ana station, outside of soil tanks, show average moisture of 2 to 3 per cent in the upper soil after a long dry period and about 12 per cent four days after a heavy rain. The former percentage is the Avilting point for this soil, while the latter is near field capacity. Samples taken from soil tanks show moisture equivalents that approximately agree with field capacities previously determined. This is shown in Table 24 of moisture equiva- lents, as determined from samples taken from above the water tables in tanks at both Santa Ana and San Bernardino. Moisture equivalents of Chino silt loam at San Bernardino are higher than at Santa Ana because of fine soil particles, as evidenced in Table 23, and a greater variation occurs at the different depths. The San Bernardino top soil has a high moisture equivalent, while for subsoil it is decreased one-half. Porosity, Specific Yield, and Specific Retention At the end of three years of investigation at the Santa Ana station and previous to dismantling the soil tanks, tests were made of the soils in various tanks to determine (1) porosity, (2) specific reten- tion, and (3) specific yield. Porosity is a measure of the total voids in a soil and is represented as a percentage of the total volume. It varies inversely with the size of soil particles and is greater for clay soils than it is for sand or gravel. Specific retention is a measure of the water holding capacity of a soil and is recorded as a percentage of the total volume. In deter- mining specific retention, it is necessary to consider the depth to water table, as more water is held in a soil in close proximity to the water table than at several feet above it. Specific yield is the amount of water which will drain from a soil by gravity. It also is measured as a percentage of the total volume. It is influenced by the size of soil particles and is greater for soils of coarse material than for soils composed of finer grains. It depends also upon the amount of capillary moisture resulting from a high water table. It is evident that both specific retention and specific yield are entirely relative and not altogether functions of the soil, as they depend on the depth to ground water and are different with each change in depth within the capillary fringe. Stearns* sa,ys, "Obviously, in any direct test, whether made in the laboratory or in the field, the true specific retention of the material can be ascertained only by using a high column of the material and disregarding the lower part that lies within the capillary fringe." In considering these characteristics, it is obvious that the specific retention is the complement of the specific yield and that the sum of the two is equal to the total porosity. Water tables in the tanks in which these tests were made were from 2 to 5 feet below the surface, or mostly within the limits of capillary rise, and therefore the specific yield and specific retention as given in this report refer only to the conditions nnder which the tests were * Laboratory Tests on Phv.sical Properties of Water Bearing Materials, by Norah D. Stearns. (U. S. Geol. Sur. Water Supply Paper 596-F, p. 13S.) 1927. WATER LOSSES FROM WET AREAS 71 made. Tliey are not true results as would be found in the absence of a water table. For example, the true speciiic yield of a soil is measured by the quantity of water which it will yield after it lias been saturated and allowed to drain. Where a high water table exists, there can not be complete drainage. A measure of specific yield is approximated by the difference between the porosity of a soil and its moisture equivalent by volunu". This represents the pore space remaining in a soil sample after it has TABLE 25 COMPARISON OF THE COMPUTED SPECIFIC YIELD OF SOILS IN THE ABSENCE OF A WATER TABLE WITH THE OBSERVED SPECIFIC YIELD OF THE SAME SOILS HAVING HIGH WATER TABLES Tank number Porosity, in per cent Moisture equivalent, in per cent by volume Specific yield, in per cent Station Computed (without water table)' Observed (with high water table) 2 1 2 10 U 314 1 3 38.3 44.8 39 5 36 4 41.9 43.5 51.3 11.5 13 5 17.4 16.8 9.1 31.2 36.9 26 8 31.3 22.1 19.6 32.8 12.3 14.4 23 0 24.5 Santa Ana 15 2 15 5 Santa Ana _ _ _ _ - 9.8 San Bernardino . _ __ - 9.9 San Bernardino _ - . 6.6 ' Computed specific yield equals porosity minus moisture equivalent by volume. = Observed specific yield equals porosity minus specific retention. ' Tank No. 14 contained disturbed soil. In all other tanks the original soil column was ujibroken. been centrifuged. To show the difference between the computed spe- cific yield and the observed specific yield as measured in the tank tests, Table 25 has been prepared. Here the porosity as determined by meas- urement minus the moisture equivalent equals the computed spe- cific yield. In the adjoining column the observed porosity minus the specific retention equals the measured specific yield. The variation in the two values is due entirely to capillary moisture resulting from a high water table. In making these tests, soil moisture was first determined in each tank and the water content of the soil was computed. Measured quan- tities of water were poured into the tanks, raising the water level until the soil was saturated. The volume of water required for saturation added to the capillary moisture was then equal to the total pore space, and fi'om this the percentage of porosity was computed. The capillary moisture above the water tables was incapable of further drainage and was, therefore, equal to the specific retention. Specific yield is the difference between total porosity and specific retention. These quan- tities are given in Table 26 for soils in various tanks at both the Santa Ana and San Bernardino stations. It is shown in this table that both specific yield and specific reten- tion vary with depth to water. The higher yields occur in those tanks having the sliallower water tables. It will be observed that porosity of disturbed soil in Tank No. 14 was close to the average of all tanks, but that the specific retention greatly exceeded that of undisturbed soil. 72 DIVISION OF WATER RESOURCES This accounts for the frequently moist surface in this tank and for the high rate of soil evaporation from disturbed soil. One column of Table 26 includes a check of porosity by computation using the formula As P^lOO (1 ), where P is porosity, As is apparent specific Sp. gr. gravity, and Sp. gr. is the real specific gravity, which has been assumed to have a value of 2.65. Chino silt loam is composed of finer material than is Hanford fine sandy loam and, therefore, the porosity is greater. The finer material holds a larger proportion of soil moisture which results in an TABLE 26 POROSITY, SPECIFIC YIELD AND SPECIFIC RETENTION OF SOIL IN TANKS HAVING HIGH WATER TABLES Station Tank number Depth to water table, in feet Depth of soil tested, in inches Specific jield, in per cent Specific retention, in per cent Observed porosity, in per cent Computed porosity, in per cent' 1 2 Mean 10 1! Mean =14 ks 3 3 3 5 5 5 2 36 0 34.08 35.04 61.2 58 44 59.82 30 12 23 0 24.5 23.75 15 2 15 5 15.35 9.8 15 3 20.3 17 8 24 3 20 9 22.6 32 1 38.3 44.8 41 55 39 5 38 4 37.95 41.9 39.6 Santa Ana -- - 36.2 Santa Ana Santa Ana 37.9 40.4 Santa Ana - 44.5 Santa Ana Santa Ana - - .. 42.45 46 9 Santa \na, Mean of all tan 40.2 41.5 San Bernardino - 1 3 11 tanks 3 2 34.56 22.2 9.9 6.6 33.6 44.7 43.5 51 3 49.8 San Bernardino- -. 43.3 San Bernardino Mean of a 47.4 46.6 > Computed by formula: Porosity=100| 1 ;ity=100l ] Apparent specific gravity Real specific gravity ' Tank Xo. 14 contained disturbed soil. In all other tanks, the original soil column was unbroken. ) increased specific retention and a smaller specific yield. For tanks having a water-table depth of 3 feet in fine sandy loam, the specific yield averaged 23.75 per cent of the volume of soil tested, but for Chino silt loam, the yield was but 9.9 per cent. The computed porosity of this soil agrees verv closelv with that found bv actual test. Apparent Specific Gravity Apparent specific gravity is defined as the ratio of the weight of a unit of dry soil to that of an equal volume of water. It is sometimes called volume weight. It varies with the soil material and is highest for soils having the lowest porosity. It is always less than the real specific gravity. Apparent specific gravity of the soils in a majority of tanks at both stations was determined for use in computing the equivalent depth of water in inches above the water table in each tank. These WATER LOSSES PROM WET AREAS 73 determinations were not made until the winter of 1931-32, when it became necessary to measure the change in water content in the soil each month, due to soil moisture increases from rainfall. Determina- tions were made fi'om samples taken from each foot of depth, using- a new soil tube. The weight and volume of each sample was obtained and apparent specific gravity computed by dividing the dry weight of the sample in grams by its volume in cubic centimeters. There is considerable variation in the results and this may account for some discrepancies in consumptive use by different soil tanks, although the majority of values are close to the mean at each station. Check determinations made at points outside the tanks agree with those in the tanks. Values found in tanks containing disturbed soil are somewhat less than those in undisturbed soil, as might be expected. It will be noticed that the top foot of soil at San Bernardino has a lower apparent specific gravity than the second or third foot. Results of all apparent specific gravity determinations at both stations are given in Table 27. TABLE 17 APPARENT SPECIFIC GRAVITY OF SOILS IN TANKS AT SANTA ANA AND SAN BERNARDINO STATIONS Tank number or loca- tion of sample Apparent specific gravity at Station Depth in feet 1 2 3 4 Mean 1 2 5 6 10 11 12 14 15 5 feet north of Tank No. 1 4 feet south of Tank No. 8 5 feet south of Tank No. 12 4 feet north of Tank No. 6 Mean 1 2 3 4 Mean 1 61 1 07 1.41 1.51 1.56 1 54 1.48 1 34 1 42 1 57 1 50 1 44 1 49 1 50 1.35 1 33 1.37 1 34 1 35 1.60 1 70 1.63 1.46 1 57 1 40 1 49 1.46 1 28 1.47 1 53 1 47 1 47 1 50 1 50 1 52 1 62 1 58 1.56 1.58 1.70 1.60 Santa .A.na 1.69 1.52 1 49 Santa .\na Santa Ana Santa .\na Santa .\na 1.64 1 45 1.44 1.46 1.53 1 49 1 48 1 58 1.47 1.47 1 42 1.35 Santa .\na 1.44 1.36 1.46 1.52 Santa Ana Santa Ana Santa Ana San Bernardino -. San Bernardino 1.57 1.56 1 54 1.44 1 51 1.58 1 44 1.48 1.52 1.49 1.51 1.43 1.45 1.50 1 46 San Bernardino.. - 1.48 1.46 CHAPTER III INVESTIGATIONS IN MOJAVE RIVER AREA By Colin A. Taylor and Harry G. Xickle * Along the ]\Iojave River there are moist areas where the non- economic use of water by natural vegetation is considerable. In Octo- ber, 1930, the State Engineer of California requested that cooperative investigations be undertaken as follows: (1) That the U. S. Bureau of Agricultural Engineering establish an experiment station along the Mojave River near Victorville for the purpose of measuring the evaporation and transpiration losses from moist areas and of recording meteorological data; (2) that the U. S. Geological Survey establish additional gaging stations along the ]\Iojave River, and an effort be made to determine consumptive use of water between stations by stream flow measurements. The work as outlined was started in November, 1930, by the cooperating agencies. Stream flow measurements along the river are still being made, but the experiment station has been dis- continued. This chapter presents the data collected at the Victorville experiment station on evaporation and transpiration losses from moist areas along the IMojave River. The Mojave River** is situated in San Bernardino County, Cali- fornia, and constitutes the chief drainage system of the northern slopes of the San Bernardino Mountains. The mountain headwaters comprise two distinct branches. East Fork, or Deep Creek, and West Fork, which unite at the base of the mountains to form the main river. This junction is known as the Forks. Below it, the river, in its course of 90 miles across the desert plain, receives no surface tributary of con- sequence, but there is an underground contribution from springs. The course of the river is first northward 30 miles, then northeastward 20 miles, and finally eastward 40 miles. The river ends in dry lakes at an elevation of less than 1000 feet above sea level. The mountain water- shed of the river, 217 square miles in area, extends from an elevation of 8000 feet at the summit of the range to 3000 feet at the Forks. The upper portion has heavy precipitation and the main tributaries are never dry where they leave the mountains. In summer the water sinks in the river a short distance below the Forks but appears again as ^sur- face flow several miles below, reaching the Upper Narrows at Victor- ville, 14 miles below the Forks. The surface flow continues through the Lower Narrows 4 miles farther down stream and during the summer again sinks several miles below Oro Grande after supplying several irrigation ditches. The water is then brought to the surface for short distances at a number of other points, these points being farther apart and the flow diminishing in ([uantity toward the lower * Prepared by C. A. Taylor, Assistant Irrigation Engineer, and Harry G. Niclcle, Junior Hydraulic Engineer, Bureau of Agricultural Engineering, U. S. Department of Agriculture. K. R. Melin of the U. S. Geological Survey assisted in conducting field work. ** Bulletin No. 5. Report on the Utilization of Mojave River for Irrigation in Victor Valley, California. State of California, Department of Engineering. (1918.) (74) WATER LOSSES FROM WET AREAS 75 end of the stream. At each point of reappearance the water supports a considerable amount of noneeonomic vegetation. Tn describing these points in tlie rivei-, Thompson* states: ''Wherever the water is at or close to the surface there is more or less evaporation, not only from the surface streams but also from the ground water supply through direct upward capillary movement and by transpiration from the plants. In some places as summer approaches the evaporation becomes so great that the water is disposed of more rapidly than it reaches the surface, and the stream dwindles and disappears. But even when the stream no longer exists water is gen- erally present a few feet below the surface, except in places where the ground water is not held near -the surface by submerged rock "dikes" or dams. xVs the end of the dry season approaches and evaporation becomes less, more water reaches the surface and the stream becomes wider and deeper and has a greater linear extent. The end of the stream may be seen to advance on cool daj's and at night and to retreat on warm days. ' ' One of the moist areas adjacent to the river extends for several miles above the Upper Narrows at Victorville. Both surface and under- ground flow must pass over the bedrock at the Upper Xarrows, and the level of the underground water immediatelv above this obstruction fluctuates little, the water being brought to the surface by the con- striction of the channel. The ground water, therefore, is usually at or near the surface over much of the area. Several flood channels have been cut through this moist area by the river during periods of high water. After careful consideration of possible sites, one of these channels, located on the east side of the river just above the Upper Narrows, was selected as the site of the Victorville station. The only surface water that enters this channel is flood water from the river and flood waters due to torrential rain storms falling upon the adjacent higher areas. The bottom of the channel has been cut down below the general ground-water level, so that there is a free stream flow of the raised water and a swampy area (cienaga) is formed. This channel is about 1600 feet in length and from 10 to 70 feet in width, is not isolated from the main moist area, and contains a dense growth of tules. The outflow from the cienaga joins the main channel of the river at the Narrows. The altitude of the station is about 2700 feet above sea level. A low earth dam was built at the lower end of the channel chosen and a Parshall measuring flume with a water-stage recorder was installed to measure the outflow. The records obtained are not given in this report but it is believed that when analyzed they may be found useful in correlating the results of the tank experiments presented in this chapter with the stream-flow measurements made by the U. S. Geological Survey in the main channel of ]Mojave River. During the latter part of November, 1930, evaporation and trans- piration apparatus was established for the purpose of obtaining basic data. Evaporation, temperature, rainfall, and wind movement records were started November 22, 1930, but no tules were planted in the tanks * "The Mohave Desert Region, California," by David G. Thompson, U. S. Geo- logical Survey Water-supply Paper 578, p. 375. 76 DIVISION OF WATER RESOURCES until January 29, 1931. Records were continued until March 1, 1933, when the station was dismantled. PROCEDURE A general view of the moivst area above the Upper Narrows is shown in Plate XI. The small flood channel on which the station is located is designated by an X marked on the plate. About midway of the length of this small channel, previously described, a section of the swamp and an area of the adjacent higher ground were inclosed with a fence for protection against animals. The bank is 4 to 5 feet higher than the level of the swamp. The enclosure is approximately 20 feet PLATE XI MOIST AREA ALONG THE MOJAVE RIVER ABOVE THE UPPER NARROWS NEAR VICTORVILLE, CALIFORNIA. by 64 feet and includes space in the swamp for the tule tanks, and space on the bank for a tule tank, supply tanks, a ground water well, and evaporation station equipment. The plan of the station is shown in Plate XXL The equipment consists of three tule tanks, a standard Weather Bureau evaporation pan, a four-cup anemometer, a set of standard maximum and minimum thermometers and a thermograph housed in a standard shelter, a rain gage, and a ground-water well. Previous investigations by Blaney and Taylor on consumptive use of water by native vegetation along stream channels* indicate that if data from tanks are to be used in estimating losses from larger areas under field conditions, the tanks should be set in a field of natural growth similar to that in the tanks. The native vegetation should completely surround the growth in the tanks so that the exposure is normal. Otherwise it is necessary to use large reduction factors the * "Bulletin No. 33, Chapter 4, "Rainfall Penetration and Consumptive Use of Water In the Santa Ana River Valley and Coastal Plain," Division of Water Resources, California State Department of Public Works. WATER LOSSES PRO"M WET AREAS 77 PLATE XII Lotver bench of Mojave Rive Direction of flow. \ \ ^'#.'" - X %- _\_.. eal-e Swamp Water line at \ edqe of sm/an^p^ I C ■ Thermomefer'i shelter I ^ -X X X X Ram < Supply Tank . Ground wsten ; A \ Tank NO I. , y PLAN OF VICTORVILLE STATION. values of which are difficult to determine, and which at best can be only very approximate. Therefore, besides the primary purpose of determining- the consumptive use of water by tules, it was desired to demonstrate the impracticability of attempting- to determine their use of water in swamps from experiments conducted with tules planted in isolated tanks outside their natural environment. Tule Tank No. 1, 2 feet in diameter and 3 feet deep, was set in the ground on the bank for the purpose of demonstrating the effect of exposure on the use of water by plants grown in tanks. The rim of this tank was set 1 inch above the surrounding ground surface. This tank was filled with soil taken from the swamp. A sparse growth of salt grass around Tank No. 1 did not reach higher than an inch at any time during the season, so that the growth in the tank had a full exposure. The evaporation pan was placed on the bank in the standard manner and had good exposure, similar to that of Tank No. 1. Two tule tanks were placed in the swamp. Tank No. 2 being 2 feet in diameter, and Tank No. 3, 6 feet in diameter. Both tanks are 3 feet deep and set in the swamp 30 feet from the bank. Cradles for the tanks were made of 2-inch redwood planks and supported on piling so that the elevation of the rims of the tanks was approximately 4 inches above the water surface of the surrounding swamp. Pipe lines wei-e connected to the tanks 1 foot below the rim and extended to supply tanks located in a sheltered dug-out in the bank. The tanks were filled with swamp soil. A ground water well was sunk in the northeast corner of the plot with a casing extending 30 inches below the ground water into a coarse ^and. Records of the height of the ground water were kept at this well, but the fluctuations were very slight. The water supply for the various tanks was obtained from a cased well about 2 feet in diameter and 3 feet deep, located near the edge of the swamp. 78 DIVISION OF WATER RESOURCES - Jt was necessary to use a supply tank with each tule tank to main- tain the water level between narrow limits. Tule Tanks Nos. 1 and 2 are directly connected to separate water supply tanks, 4 feet in diameter and about 1 foot deep. A cone-shaped metal cover with an air vent was fitted over the supply tanks, and a second cover was placed over the sui')ply tanks to eliminate evaporation. With this arrangement the fluctuations in the water surfaces of the tule tanks are reduced by the replenishment of water from the supply tanks. Plate XIII shows PLATE XIII $yvamp water surface r^fi/jyyQH ^■h=-=^ TanH N92 / dank P'P^^ \ %'p>P^ Supply tank B (O 4 ARRANGEMENT FOR TANK NO. 2 TO SUPPLY WATER AND TO MEASURE AMOUNT OF EVAPORATION AND TRANSPIRATION. PLATE XIV ^- 3y/amp wafer surface ace-^ TanH No- 3. » VaJve I 5fillyyell r=75^ ARRANGEMENT FOR TANK NO. 3 TO REGULATE SUPPLY OF WATER AND TO MEASURE AMOUNT OF EVAPORATION AND TRANSPIRATION. WATER LOSSES PROM WET AREAS 79 PLATE XV W. A. GENERAL VIEW OF VICTORVILLE STATION, TAKEN OCTOBER 31, 1931. B. VIEW TAKEN OCTOBER 31, 1931, OF SWAMP WHERE TWO TANKS WERE LOCATED, THE STADIA ROD BEING HELD BETWEEN THE TWO TANKS. 80 DIVISION OF WATER RESOURCES the arrangement to supi)ly water for tule Tank No. 2 and also 'the still well for measuring- the amonnt of water used. Because of the volume of water required to supply tule Tank No. :>, a different arrangement was necessary there. This tank was supplied through an automatic float-valve feed connected to a supply tank of larger capacity. Plate XIV shows the arrangement for regulating the supply of water and measuring the amount used in tule Tank No. 3. Beginning November 22, 1930, Tanks Nos. 1, 2, and 3 were main- tained with free water surfaces until January 29, 1931, when they w'ere planted with tules {Scir])iis olnciji). During the installation of the equipment, the old tules around the tanks were broken down and the tanks were not completely surrounded with new growth until about ]\Iay, 1931. Prior to May 15 the side exposure of Tank No. 2 was some- what greater than that of Tank No. 3 but after that date the surround- ing growth completely hid the rims of both tanks and thereafter the exposure of the tules in Tanks Nos. 2 and 3 Avas similar to tliat of the natural swamp tules. PLATE XVI 1,%^ •i -.^> ft. VIEW OF TANK NO. 1, TAKEN OCTOBER 31, 1931. WATER LOSSES F^ROM WET AREAS 81 Plate XV-A is a general view of the station taken October 31, 1931, showing the location of the cliniatolopieal apparatus, while Plate XV-B shows the location of Tanks Xos. 2 and 3, in the swamp, where they are surrounded by natural swamp growth. Plate XVI, taken on the same date, shows the tule growth in Tank No. 1. CONSUMPTIVE USE OF WATER Table 28 records, by months, for the period from February 1, 1931, to February 28, 1933 ; the evaporation from a standard Weather Bureau pan ; the consumptive use of water from tule Tanks Nos. 1, 2, and 3 ; a percentage comparison of the consumptive use of water from the tule tanks expressed in per cent of the evaporation ; the wind move- ment ; the rainfall ; and average daily maximum and minimum tempera- tures. A comparison of the losses, from February, 1931, to February, 1932, from the three tule tanks and from the evaporation pan is shown graphically in Plate XVII. PLATE XVII 60 C 01 30 Or 20- O'T Q-O) 10- DIM m Feb. 1 Mar. Apn , May Jui'^g ; July Aug. |Sept. j Oct. ) Nov. | Dec. 0 Standard Weather Bureau Fi evaporation pan 4ft in diameter:[j -Tank No I, Two ft. in diameter, located on bank. Tank N^Z, Two ft. in diameter; located in swamp. Tank N03, Six ft. in diameter, located in swamp. 1931 '"1 \~m7inrr^M~h^M~y^ Jan. Feb. 1932 MONTHLY EVAPORATION AND USE OF WATER FROM TANKS NO. 1, NO. 2. AND NO. 3, FEBRUARY, 1931-FEBRUARY, 1932. In April the tules in Tank No. 1, located on the bank, began to use water at a relatively high rate that increased rapidly until the highest use Avas reached in July, when it amounted to 4.55 times the evajioration, or 55.83 acre-inches per acre. After reaching a peak in July and August the use dropped until the plants were killed by frost in November, after which there was a continued loss by evapora- tion. There was practically no green growth in this tank until May, 1932, as indicated in Table 28, the use being shown to be much less than the evaporation from the AVeather Bureau pan in March and April. After the tules .started to grow in 1932 they used Avater rapidly until the highest use was reached in August, when it amounted to 78.99 acre-inches per acre, which was 6.77 times as great as the evaporation from the Weather Bureau pan. The use of water from tule Tank No. 2, located in the swamp, was found to be considerably less than that from Tank No. 1 as the growing season advanced, although the tanks were of the same diameter. In 6 — 4503 82 DIVISION OF WATER RESOURCES H Z u o Q CO CO u (I. o u a^ o (J- >. 3 C0'> ZH H CO ^^ S< O W a; Oj W H > < ^ z > ^ 1^ 3 u 7^ 0> Uo z2 2q Pz ^^ °^' < o > '-' •< 50 ^ < o > X w < to I H Z o B g s Q3 R lO "^ -a 2 — ■|i-a s o c ^ 0) c^ C o o J; £ =25 C C t- HI'S a> Cm ^ O O) _5 -; « 6 o K cS c3 o "^ CC^-CO-^OQOOCKiOC^CO (MI--0Ca3^^-O — O — '— I CO — lO CO -;:■_ 9- - o =3 s; rt to ■^o ca a — O o S § 1» 1— i-^t^^-iM'^'— 'Om»-' ^- .-■ c^ M »o C5-eo c^ C5 -^ CO c^ a, .-S g g ^ coooc 3 o ■^■^ o k. 3 u O C3 « WATER LO^iRES FRf^r WET AREAS 83 1931 the highest use from Tank No. 2 occurred in May, before the tank was entirely surrounded by swamp growth, and amounted to 16.03 acre-inches per acre, while the highest use for Tank No. 1 occurred in July, and amounted to 55.83 acre-inches per acre. The use in July from Tank No. 2 was 14.37 acre-inches per acre, which is approximately one-fourth of the use from Tank No. 1 for that month. This difference must be due to the relative exposures of the two tanks, since the density of stalks was not materially different. When the tules were set out in 1931 the plants in Tank No. 2 started to grow and use water earlier than the plants in Tank No. 1, because they were warmed by the rising water that flowed around the tanks in the swamp. A flood in May, 1932, damaged Tank No. 2 and the connected supply tank, so that the record from this tank is incomplete for 1932. The record for 1931, however, supplied the data necessary for the principal objective — demonstration of the effect of exposure on the use of water from 2-foot tanks. This is shown graphically in Plate XVII. A comparison on a mean monthlv basis for the entire period of record is shown in Plate XVIII. * PLATE XVIII Jan. \ Indicating excessive use 44*^ of tvafer, due to plants y//y_ \in no I Tank being _ away from natural environmenf. Nov. Dec. MEAN MONTHLY EVAPORATION AND USE OF WATER FROM TANKS NO. NO. 2, AND NO. 3. 1, A complete record was obtained from tule Tank No. 3 during both the 1931 and 1932 seasons. This tank was 6 feet in diameter and had a normal swamp expo.sure with a growth of tules completely surround- ing the tank, so that there was a replication of natural conditions. The highest monthly use of water from this tank occurred during July in each year, amounting to 14.65 acre-inches per acre in July, 1931, and 13.61 acre-inches per acre in Juh% 1932. The mean annual use of water from this tank based on the 25-month period from February, 1931, to February, 1933, is 78.45 acre-inches per acre. This value was 84 mvisTox OF water resources obtained by averaging the monthly values for each calendar month and then totalino- these twelve monthly averages. . This value, 78.45 acre-inches per acre per year, represents the average annual loss of water dnring this period from tule swamps of the area with the water table at the ground surface or above. No reduc- tion factor should be applied to this value, since the tank was set in a SAvamp and completely surrounded by a growth similar to that in the tank. The rim of the tank Avas completely hidden from the rays of the sun so there conld be no rim effect, and the tank was bedded nearly 3 feet deep so that there conld be no abnormal temperature variation or restriction of root activity. ^Measured losses from the moist area on Temescal Creek compare favorably' with the losses from the 6-foot tank at Victorville. The loss for\he 30-day period from April 28 to May 27, 1929, for the swamp growth on Temescal Creek was 12.9 acre-inches per acre.* For the month of May, 1931, tule Tank No. 3 at Victorville nsed water at the rate of 11.62 acre-inches per acre per month, and the maximum rate measured in July, 1931, was 14.65 acre-inches per acre per month. The cross-hatched area on Plate XVIII shows the relatively large loss of water from Tank No. 1 as compared with Tanks Nos. 2 and 3, where natural conditions were replicated. In this connection, it will be noted in Plate XV that the tule growth in the tanks in the swamp was 6 feet high, whereas the growth in Tank No. 1 on the bank (Plate XVI) averaged approximately 3 feet in height. These pictures were taken October 31, 1931. This indicates that the number of pounds of dry matter produced in the different tanks bears no rational relationship to the amount of water consumed when tules are grown in exposed tanks, such as tule Tank No. 1. That is, the loss of water from a natural swamp can not be computed from the relation of pounds of water used per pound of dry matter produced as determined from tules grown in isolated tanlcs. During July and August, 1931, Tank No. 1 used between three and four times as much water as either Tank No. 2 or Tank No. 3, yet the ultimate size of the plants produced in Tank No. 1 was only one-half the size of the plants in the swamp tanks. The results indicate that the controlling factor in the consumption of water is the exposure of the tanks and demonstrates, quite forcibly, that natural conditioixs must be replicated before data are of value in estimating field losses. The diameter of a tank is a factor of importance when evaporation from a free water surface is being measured, as demonstrated by R. B. Sleight.** For the period from March 5 to November 13, 1916, Sleight found the evaporation from a 2-foot tank to be 117 per cent of that from a tank 6 feet in diameter. However, with plants growing in a tank set in a similar growth of sufficient density so that radiation from the sun does not strike the edges of the tanks, the size of the tank should not materially affect the rate of loss per unit area from like densities of plant growth. Before May 15, 1931, the surrounding swamp growth had not shielded * Bulletin No. .3 3, "Rainfall Penetration and Consumptive Use of Water In the Santa Ana Hiver Valley and Coastal Plain," Division of Water Resources, California State Department of Public Works (Page 68). ** "p:vaporation from the Surface of Water and River-bed Material," (Journal of Agricultural Research, Vol. X, No. 5, July, 1917.) WATER LOSSES FROM WET AREAS 85 the tank rims fully and tiile Tank No. 2 shows the higher rate of loss. Thereafter, differences in losses from the two tule tanks may be ascribed to a variation in the density of growth. By comparing the losses from tnle Tanks Xos. 2 and 3, from Juno 1 to October 31, 1931, it is found that the loss is 49.93 acre-inches per acre from the 2-foot tank, and 55.08 acre-inches per acre from the 6-foot tank. For this period, the loss from the 2-foot tank is 91 per cent of the loss from the G-foot tank, as compared to Sleight's ratio of 117 per cent for free water surfaces. The correlation of tank size is negative and diffci-ence in use must be due to some other factor such as density of growth. Prior to the planting of tules in the tanks on January 29, 1931, all three tanks were maintained with free water surfaces. The evapora- tion in inches and rate of evaporation in inches per 30 days for the Weather Bureau pan and Tanks Nos. 1, 2, and 3, and also the evapora- tion from Tanks Xos. 1, 2, and 3, expressed as percentages of the evapo- ration from the Weather Bureau pan for the period, December 5, 1930, to January 29, 1931, are given in Table 29. During the period of these TABLE 29 EVAPORATION FROM FREE WATER SURFACES IN THE WEATHER BUREAU PAN AND TANKS NOS. 1, 2, AND 3 December 5. 1930, to January 29, 1931 Pan or tank Standard Weather Bureau pan (4 feet in diameter) Tank No. 1 (2 feet in diameter) located on bank near Weather Bureau pan Tank No. 2 (2 feet in diameter) located in swamp ._ Tank No. 3 (6 feet in diameter) located in swamp Total evaporation in inches 4 20 2.16 6 91 4.19 Rate of evaporation in inches per 30 days 2.29 1.18 3.77 2.29 Per cent of evaporation from standard Weather Bureau pan 100 51 165 100 evaporation .studies from free water surfaces, the mean daily maximum temperature was 65 degrees Fahrenheit, the mean daily minimum tem- perature was 11.5 degrees Fahrenheit, and the total wind movement was 1389 miles. The evaporation from the 6-foot tank (Tank No. 3), located in the swamp, was practically the same as that from the Weather Bureau pan (4 feet in diameter), the values being 4.19 and 4.20 inches, respectively, while the loss from the 2-foot tank (Tank No. 2), located in the swamp, was 165 per cent of that from the Weather Bureau pan. The 2-foot tank (Tank No. 1), located on the bank near the evaporation pan and set in the ground so that its rim was 1 incli above the sur- rounding ground surface, lost 51 per cent as much as the Weather Bureau pan. This demonstrates the effect of exi)osure and location on the rates of loss from the different tanks. Tanks Nos. 2 and 3 were located in the .swamp and the rising ground water from the swamp channel flowed around them continuously. Tlie rising water in the swamp carried .sufficient heat so that no ice formed on the water surface around the two tanks, even though a minimum air temperature of zero degrees Fahrenheit was recorded on December 23, 1930. The heat from this swamp water was transmitted to the water in the tanks most effectively 86 DIVISION OP WATER RESOURCES in the case of the small tank 2 feet in diameter and to a less extent in the case of the 6-foot tank. The Weather Bureau pan, 4 feet in diameter and 10 inches deep, is set entirely above the ground, and receives heat from the sun on its sides as well as on the water surface, and it has also a maximum exposure to air movement. The 2-foot tank, located on the l)ank and sunk in the ground, could receive but very little heat energy from the dry cold ground surrounding it, but probably some of the heat received on its water surface was conducted down through the water and away into the soil. Accordingly, the evaporation from the 2-foot tank on the bank was least ; and that from the 2-foot tank in the swamp was greatest, the latter being, in fact, 8.2 times as much as the former. The water in Tank No. 2 received enough heat energy from the swamp water to keep it relatively warm, while the water surface in Tank No. 1 remained relatively cold. The fact that the rate of evaporation is relatively high when the temperature of the water is greater than that of the air, has l)een pointed out by Rohwer.* A comparison of the evaporation from Tanks Nos. 2 and 3 shows the loss from Tank No. 2 to be 1.65 times that from Tank No. 3. It is of interest to note that studies at the Salton Sea in 1910, using exposed tanks, showed a ratio of 1.48 to 1 for the loss from a 2-foot tank com- pared to that from a 6-foot tank.** In 1916, Sleight found the ratio of the loss from a 2-foot tank to that from a 6-foot tank to be 1.17 to 1 for tanks sunk in the ground. The higher ratio found at the Victor- ville station is luidoubtedly due to the heating effect of the surrounding water as noted above. As stated above, Table 29 indicates that the loss by evaporation from the free water surfaces in the cienega is relatively high during tlie winter. The reason for the high losses is that the rising water is relatively warmer than the air during the winter months. In further demonstration of the extreme effect of exposure on rates of evaporation and transjnration from tanks, it should be noted that during December and January Tank No. 1 lost b.y evaporation less than one-third as much as Tank No. 2, but, in Jul.v, 1931, conditions were reversed and the consumptive use by evaporation and transpira- tion from the tules in Tank No. 1 was nearlv four times as much as from Tank No. 2. Mean monthly values for the entire period of record, for the evaporation and use of water from tule Tanks Nos. 1, 2 and 3, together with the climatological data, are given in Table 30. The mean annual evaporation from the Weather Bureau pan, as shown in Table 30, was 82.46 inches. Tlie mean annual consumptive use of water from tule Tank No. 1, which liad the same ex]iosure on the bank as the evaporation pan, was 272.24 acre-inches per acre, Avhile from tule Tanks Nos. 2 and 3, located in the swamp and characteristic of swamp conditions, there were used 84.45 acre-inches per acre and 78.45 acre- inches per acre, respectively. Plate XVTTI shows the mean monthly evaporation and use of water from Tanks Nos. 1, 2 and 3. * "Kvai^oration from Free Water Surfaces," by Carl Rohwer, United States Department of ARriciiUure, Technical Bulletin, No. 271. (1931.) ** Studies on the Phenomena of Evaporation of Water Over Lakes and Reservoir.s. Summary of the Results of the Salton Sea Campaign. By F. H. Bigelow. Monthly Weather Review, Vol. 38, No. 7. (1910.) WATER LOSSES FROM WET AREAS 87 TABLE 30 SUMMARY BY MONTHS OF MEAN TEMPERATURES, WIND MOVEMENT, EVAPORATION, AND CONSUMPTIVE USE OF WATER FROM TULE TANKS NOS. 1, 2, AND 3, AND USE OF WATER FROM TULE TANK NO. 3, EXPRESSED IN PER CENT OF EVAPORATION AT VICTORVILLE STATION' Temperature, in degrees Fahrenheit Wind move- ment, in miles Evapora- tion from a standard Weather Bureau pan (4 feet in diameter) in inches Use of water, in acre- inches, per acre Use of water from tule tank No. 3, in per cent of evaporation from standard Weather Bureau pan Month Mean maximum Mean minimum Tule tank No. I (2 feet in diameter) located on bank Tule tank No. 2 (2 feet in diameter) located in swamp Tule tank No. 3 (6 feet in diameter) located in swamp .Tanuarv 52 55 70 74 81 86 97 94 88 76 66 52 21 24 30 35 42 46 52 52 44 37 26 22 1,458 1,299 1,680 1,818 1,746 1,396 1,245 1,114 1,044 1,020 897 1.120 2.40 3.32 6.67 7.79 9.92 10 38 12.12 10.68 8.22 5.44 3.52 2.00 2.81 2 54 4.61 7.25 17.62 35 47 63.38 59.54 46 38 25.28 4 61 2.75 1.74 3.08 5.26 8.16 11.11 14.21 14 37 9 87 7.17 4.31 3 05 2.12 1.74 2.02 3.82 5 08 8.78 10.80 14 13 12 32 10 04 5.86 2.42 1.44 72 February March .\pril May 61 57 65 89 104 .Julv 117 .August... 115 Seotember . . . 122 October 108 NovemI:)er 69 December 72 Totals per year 15,837 82.46 272.24 84.45 78.45 ^5 ' This table is based on all data from February 1, 1931, to February 28, 1933. ' Per cent based on totals per year. As tule Tank No. 3 replicated SAvamp conditions, the mean annual use of water from this tank was employed in determining a factor to be applied in calculating- swamp use from an evaporation pan record. As the mean annual evaporation from the standard Weather Bureau pan was 82.46 inches and the mean annual use of water from tule Tank Xo. 3 was 78.45 acre-inches per acre, the use of Avater from the tule swamp area Avould be 95 per cent of the eA^aporation from the Weather Bureau pan. The evaporation from a lake surface may be estimated as 0.7 of the mea.sured loss from a standard Weather Bureau pan. The mean annual evaporation from a lake surface is, therefore, indicated to be 58 inches. The mean annual loss from tule Tank No. 3, Avhich replicated natural conditions, Avas 78.45 inches. This indicates that the annual use by tules would be 20 inches more than the loss from a lake surface. Tliis is probably a maximum differential and Avould be expected in a swamp area completely coA^ered Avith tules groAving in water. It may be seen from Plate XI that a considerable portion of the moist area aboA'e the Narrows is coA'ered Avith a scattered groAvth of cottonwoods interspersed with patches of open sandy areas. The dense tule groAvths are restricted principally to sections along the main chan- nel of the riA'er and in the swampy areas such as the one on which the station Avas located. The mean annual consum]:)tiA'e use for the entire moist area Avould undoubtedly be appreciably less than the value of 78 acre-inches per acre per year determined for the tule sAvamp areas. If the period from ]May to October, inclusive, be considered, and a comparison made for that interval, it is found that tlie use of Avater by the tules Avas 61.93 inches, and the estimated evaporation from a lake surface, 40 inches. The difference is 22 inches, and for this period, the loss of water from a tule sAvani]) area would be 155 per cent of the loss from a free Avater lake surface. CHAPTER IV INVESTIGATIONS IN COLDWATER CANYON By Colin A. Taylor and Harry G. Nickle* In many instances water supplies for irrigation, domestic, and industrial uses are diverted from the lower reaches of canyons and the water is allowed to flow through many miles of open channel bordered by growing vegetation. A large portion of the water used originates in the mountain watersheds and must pass through the canyons before it reaches the irrigated areas of the valleys. There is little information available as to the amount of water lost in such canyons through evaporation and transpiration from the native vegetation. Losses from the moist land bordering the lower sections of Temescal Creek, four miles southeast of Corona, were investigated by the Divi- sion of Irrigation of the Bureau of Agricultural Engineering early in 1929. The growth was typical of the moist areas bordering the streams in the valleys, with willows and tules predominating. The results ** indicated that large losses must occur from similar growths along the Santa Ana River and that the supply of water diverted in the lower Santa Ana Canyon for irrigation in Orange County must be consider- ably diminished because of the loss of water in the moist areas adjacent to the river. Since the losses from the areas supporting willows, tules, and kindred moist land growths were indicated to be of considerable magni- tude, it was deemed advisable to extend the study to canyon reaches in which alder growths predominated, above the usual points of diver- sion from the streams. It was the purpose of this study to obtain data on the loss of water during the growing season by evaporation and transpiration from a typical small canyon and on the amount of addi- tional water which might be derived were the water supply diverted at a higher point on the stream. The experimental data for this stud}' were obtained in Coldwater Canyon, located near ArroAvhead Springs in the San Bernardino Mountains in the upper basin of the Santa Ana River, approximately 7 miles north of the city of San Bernardino. This canyon was chosen as being representative of many of the smaller canyons of southern California. The data were collected during the growing seasons of 1931 and 1932. In 1931, two bedrock stations, hereinafter called "controls," were installed in the canyon. The "lower control" was located about one mile above the mouth of the canyon, and the other, designated as the "middle control," was located 2090 feet upstream from the lower * Prepared by C. A. Taylor, Assistant Irrigation Engineer, and Harry G. Nickle, Junior Hydraulic Engineer, Bureau of Agricultural Engineering, U. S. Department of Agriculture. ** "Rainfall Penetration and Consumptive Use of Water in Santa Ana River Vallev and Coastal Plain," by Harry F. Blaney and C. A. Taylor, State of California, Department of Public Works Bulletin No. 33, Chapter IV, 1930. (SS) WATER LOSSES FRO'Sl WET AREAS 89 PLATE XIX n '-'(•. ^^: 73 J o X z o o a H O •-V Z o < y o J o 2 O Z o > z < u H < „...,^,j^ r .^ 4, V ■ ^^**. ,>i '\>Si^^- Q o u < en a < 90 DIVISION OF WATER RESOURCES control. In 1932 the same controls were continued and, in addition, another bedrock control, designated as the "npper control," was installed 5875 feet npstream from the middle control, and a snpple- mentary bedrock control was installed on the only branch entering- the main canyon from the east between the middle and lower controls, at a point about 300 feet above its month. This branch canyon enters the main canyon 800 feet above the lower control. The approximate elevations above sea level of the conti'ols are 2300 feet for the lower control, 2500 feet for the middle control, and 3100 feet for the upper control. A general view of Coldwater Canyon is shown in Plate XIX, the white marks indicating the location of the controls. The canyon bottom vegetation between the controls is composed mostly of alders, bay (California laurel), sycamore, willow, and maple, with a few oak, mountain mahogany, cedar. si:)ruce, and cottonwood trees. Also, there is considerable smaller growth of grapevine, black- berry, poison oak, ferns, etc. Table 31 shows the number and kinds TABLE 31 CLASSIFICATION OF TREES BETWEEN MIDDLE AND LOWER CONTROLS IN COLDWATER CANYON Number of trees Diameter, in inches Alder Sycamore Bay Willow Maple Oak Mountain mahog- any Total Less than 2 33 159 144 150 105 59 33 16 13 13 11 1 3 16 10 8 ti 3 4 10 1 1 2 4 30 2 1 14 2 7 4 6 1 1 2 2 51 2- 4 1 227 4- 6 162 6- 8 166 8-10 112 10-12 64 12-14 1 40 14-16 23 16-18 23 18-20 .-- 2 16 20-22 12 22-24 3 36-38 1 1 Totals Per cent 737 81 9 71 7.9 37 4 1 25 2.8 23 2 5 5 0.6 2 0.2 900 100 0 of trees between the middle and lower controls, and Table 32 is a similar table of the trees between the upper and middle controls. These two tables show the difference in vegetation of the two sections of the canyon. In the lower section the alders constitute 81.9 per cent of the total number of trees, while in the upper section they consti- tute only 47.9 per cent of the total number. The lower percentage of alders in the upper section is accounted for principally by the increased number of bays which constitute but 4.1 per cent in the lower section, but make up 26.1 per cent of the total in the upper section. The lower section has a higher percentage of larger trees, while between the upper and middle controls the percentage of smaller trees is the greater and also the number of different kinds is greater. Views of the canyon bottom vegetation between the middle and loAver controls are shown in Plate XX. WATER LOSSES FROM NVKT AREAS 91 PLATE XX A. ALDERS IN CANYON BOTTOM VIEWED FROM AN OVERHANGING CLIFF. B. ALDERS IN CANYON BOTTOM ABOUT MIDWAY BETWEEN THE MIDDLE AND LOWER CONTROLS. 92 DIVISION OF WATER RESOURCES TABLE 32 CLASSIFICATION OF TREES BETWEEN UPPER AND MIDDLE CONTROLS IN COLDWATER CANYON Number of trees Diameter, in inches Alder Bay Maple Willow Syca- more Oak Moun- tain mahog- any Cedar Spruce Cotton- wood Total Tjpco than 2 67 222 193 242 184 175 84 48 26 15 13 12 3 2 258 371 52 11 5 3 1 48 81 56 26 10 5 5 1 1 62 82 24 8 3 1 1 11 60 34 24 15 18 32 4 2 30 8 1 5 1 1 495 2- 4 861 4- 6 364 6 -8 314 8-10 1 218 10-12 184 12-14 9 7 2 3 3 1 3 101 14-16 59 16-18 29 18-20 . - 1 19 20-22 1 17 22-24 1 13 26-28 - 3 28-30 2 30-32 1 2 1 1 2 3 34-36 1 2 36-38 1 38-40 1 3 Totals.. Per cent 1,286 47.9 701 26 1 234 8.7 181 6.7 169 6 3 63' 2 4 38 14 9 0.3 6 0.2 1 0.0 2,688 100.0 Above the upper control the growth in the main canyon bottom is principally alders, with some sycamores, willow, maple, bay, etc. The main canyon divides into two main branches, at a point 1920 feet above the upper control. Many of the smaller branch canyons above the forks have dense groAvths of ferns and underbrush. Between the middle and low^er controls there are only two branches entering" the main canyon, one from the east on which the branch con- trol was located, and one from the west vhich has an excellent bedrock exposure just as it enters the canyon. The west branch canyon con- tributed no water during the periods recorded in this report. There were no visible indications of water entering the canyon between the middle and lower controls during the period of record, except during the first part of the 1932 season as measured at the branch control. There are several branch canyons entering the main canyon betw^een the upper and middle controls. There were no visible indications of any water entering- the canyon betAveon these controls at any time during the 1932 season. The material filling the main canyon bottom between the middle and lower controls ranges in width from 25 to 80 feet for the most part, and has an average width of 49 feet and an area of 2.36 acres. Between the upper and middle controls, tiie material filling the canyon bottom ranges in width from 15 to 80 feet for the most part, and has an average width of 44 feet and an area of 5.89 acres. On both sides the canyon walls are very precipitons. The length of canvon in which surface water flowed was measured in October, 1931, after the flow had recovered to its maximum connected flow for the season. Above the forks, 1920 feet from the upper control, there were 13,170 linear feet of branch canyons in which surface water WATER LOSSES FR01\T WET AREAS 93 was flowin. Tliis makes a total above tlie upper control of 15,090 linear feet of canyon, including' all the branches, that had flowing water at the end of the 19;?1 p'l'owing season. Above the lower control the area of the watershed is 3.4 square miles, of which area the east branch, on which the branch control is located, drains 0.9 s(}uare mile. Records were obtained during the 19)11 season at the middle and lower controls on the main canyon, from August 1 to October 17, and also during the 1932 season at the three controls on the main canyon, from June 24 to November 3. Water was also measured at the branch control from June 24 to July 9, 1932, no water passing this branch control at any other time during the periods of record. EQUIPMENT Controls In 1931, the two bedrock controls were established in Coldwater Canyon at the locations previously described. At each of these con- trols, a low concrete dam was biiilt on bedrock across the bed of the stream. The flow of water was passed through a 3-incli Parshall meas- uring flume placed in one end of each dam, and water stage recorders were installed to record the head on each flume. On September 17 of the same year a flow recorder for recording the discharge directly was installed at the lower control and Avas operated during the remainder of the season. The flow recorder is described in detail on page 96. PLATE XXI MIDDLE COLDWATER CONTROL SHOWING 3-INCH PARSHALL MEASURING FLUME AND FLOW RECORDER. 94 DIVISION OF WATER RESOURCES In 1932, flow recorders operated with 30-inch floats were installed at the two controls operated in 1931 and bedrock exposures were selected for the locations of the upper and branch controls. Low con- crete dams were built on these sites and the flow passed through flumes in the dams, water stage recorders being set for recording the gage heights. Plate XXI is a view of the middle control showing the 3-inch Parshall measuring flume and the flow recorder. Flume for Winter Measurements In order to measure small summer floAvs accurately and also to obtain a record of large winter flows, a combination flume, such as is shown in Plate XXII, was found desirable. This combination flume consists of two Parshall measuring flumes, one large and one small, so arranged that both large and small flows pass through the converging section of the large flume, but the small flows are by-passed from the dip in the large flume into a basin above the small flume and thence through this latter flume, while the greater part of the large flows continues on through the larger flume. A record of the larger discharges is obtained by a recorder operated by a float in a still well connected to a larger flume, and a record of the smaller discharges is obtained by a flow recorder operated by a float in a still well connected to the smaller flume. Some overlap is j)rovided so there is a small range during which a record may be obtained from both flumes. Two separate recorders may be used, or one duiDlex recorder is sufficient if it is desired to record gage heights only. Plate XXII shows a combination of 3-inch and 2-foot Parshall measuring flumes, providing a range in discharge up to 23 second- feet. The sizes of both flumes may vary according to the accuracy and range desired. It should be recognized, however, that there are certain limitations on the accuracy of measurements over very wide variations in flows, and the selection of sizes should depend on whether the greatest accuracy is desired at very high, medium, or low stages. The application of Parshall measuring flumes to measurements in mountain canyons involves problems not ordinarily met with in valley areas. The stream gradient is steep, often 10 per cent or more, and the water tends to cut a narrow channel and travel at a relatively high velocity and carry a large bed load as well as a considerable amount of suspended material. A large flume placed, for example, directly in a stream channel where the grade is as high as 10 per cent will have a rating curve quite different from the standard calibration. It may pass as much as 30 per cent less water than that given for the lowest gage heights in the standard tables. The reason for this is that a small stream of Avater entering the center of a wide flume at high velocity tends to proceed through the center of the flume without changing its cross section greatl}', leaving dead water along each side of the wide flume. . At high stages, the flume may pass more water than is indicated by the gage height in the standard tables, because of the high velocity of approach WATER LOSSES FRO.Ar WET AREAS 95 PLATE XXII COMBINATION FLUME FOR MEASUREMENT OF WATER AT BOTH HIGH AND LOW STAGES. across the entire width of the flume. The large flumes should, therefore, be rated iu place when the conditions are extreme, such as are indicated in the example cited. With clear water it is best to set the gaging station so that there is the least possible grade in the approach channel to the flume. "Where heavy loads of detritus are being transi)orted, deposition will occur in tlie entrance to the flume where the grade is flattened at the installa- tion, and enough debris may lodge to affect the measurement. Usually, however, other conditions, sucli as bedrock exposure in the channel, will determine the location of the station, and it will be found more economical to rate the large flume for the given set of conditions after other factors have determined its location. % DIVISION OF WATER RESOURCES Flow Recorders At first when ordinary water stage recorders were used it was necessary, in order to obtain sufficient accuracy, to take off hourly values from the water-stage recorder charts. The work of taking off these hourly values and from these values computing the loss each day was found to be a long and laborious process. In order to eliminate a large part of this routine work, thereby saving much time, it was decided to use flow recorder attachments on the recorders at the controls. Accordingly, a flow recorder attachment was purchased and installed in Coldwater Canyon in conjunction with the water stage recorder at one of the controls in September, 1931. This flow recorder attachment consisted essentially of an adjustable spiral cam that mechanically solved the flow formula. The cam was geared to a float pulley wheel and the pencil cord was attached to the cam. The float turned the pulley wheel and. through the cam, moved the pencil to record the flow directly in units of discharge. A flow recorder installa- tion is shown in Plate XXIII. PLATE XXIII FLOW RECORDER INSTALLATION AT LUWKK CULUVVATh-K CONTROL. WATER LOSSES FROM WET AREAS 97 This first flow recorder attaeliment was installed to operate by a 12-incli float. After testing in the field, it was found that the pencil lag- on the record chart was too great for tlie work being undertaken. This lag amounted to as much as 0.020 second-foot and as the fluctua- tions that were being measured amounted to 0.200 second-foot and less, the error was 10 per cent or more. In order to secure greater sensitiveness, the gears were eliminated, the cam was balanced, and a 30-inch float was used. Nonadjustable cams were designed and made for use with 3-inch Parshall measuring flumes. With the improved flow recorder attachment, the pencil lag was reduced to 0.002 second-foot for flows above 0.50 second-foot, and for flows of less than 0.20 second-foot no lag could be detected. By using these flow recorder charts, the loss per day may be obtained directly by superimposing two charts, one from each control, on top of a light-table, and planimetering the area between the two curves. This area represents the daily loss between controls and, when multiplied by the proper constant, can be converted into whatever units are desired. Evaporimeter It became apparent, during the course of the investigation of the loss of water along stream channels by evaporation and transpiration, that the study would be materially aided if a continuous record could be obtained of the transpiration opportunity. Briggs and Shaiitz* showed that the evaporation from a shallow black pan correlated more closely with actual transpiration than that from any of the other devices which they tested. Loss of water from deep paas is affected by heat storage within the water. During the morning much of the heat received from the sun is used in raising the temperature of the water, and if the tank is 10 inches or more deep there is a lag of several hours in the curve of evaporation, behind the cycle of insolation. As the depth is decreased, the lag becomes less. The practical lower limit for the depth to be used appeared to be that depth which would be sufficient for one complete day's record on the hotter days. The 4-foot pan maintained at Ontario from 1928 to 1930 showed a peak rate of slightly less than 0.50 inch per day; therefore 0.60 inch was chosen as the most practical maximum depth for the water in the evaporimeter. A Fergusson recording rain gage was used as the recording device. The evaporimeter pan was made 2 feet in diameter and 0.7 inch deep. This pan was attached to a cylinder that would fit inside tlie rain gage and take the place of the usual rain-gage bucket. The pan and recorder were then placed in a box 30 inches square by 27 inches high, to provide lateral heat insulation. The evaporimeter is shown in opera- tion in Plate XXIV-A with a standard 8-inch rain gage to the right. The recording mechanism is shown in Plate XXIV-B. The chart scale is 9 to 1 ; that is, 9 inches on the chart is equivalent to 1 inch of evapo- ration. Record charts are shown in Plate XXV for typical days in August and October, 1931. * Reprint from Journal of Agricultural Research, Vol. IX, No. 9, May, 1917. "Comparison of the Hourly Evaporation Rate of Atriiometers and Free Water Sur- faces with the Transpiration Rate of Medicago Sativa," by Lyman J. Briggs and H. L. Shantz. 7—4503 98 DIVISION OP WATER RESOURCES PLATE XXIV A. EVAPORIMETER WITH SHALLOW BLACK-PAN 24 INCHES IN DIAMETER. B. EVAPORIMETER SHOWING WEIGHING MECHANISM AND RECORD CYLINDER. WATER LOSSES FROM WET AREAS 99 Wind action affects the instrument, since the change in air pressure, as each gust passes, causes a vertical movement of the pan and pro- duces a wavy line on the chart. In this way a continuous record is obtained of the time the wind blows and also a relative indication of its intensity. During cold winter months the water in the shallow pan freezes solid, and an accurate record of the evaporation from an ice surface may be obtained since the mechanism is of the weighing type. PLATE XXV >' re o .fl ,. V.--. t i 3 « - " ■ - ' ,- ■ o r "v t J: X. n t--tf7C7 o/'v ■ :■ vd? T-~-- EVAPORIMETER CHARTS. EVAPORATION AND TRANSPIRATION LOSSES ALONG THE STREAM CHANNEL Loss from Stream Between Controls The loss from a section of canyon was obtained by subtracting the volume of water leaving from the volume of water entering the section. Because of a possible storage differential in the section between the beginning and the end of any period, this method will result in small departures from the true dift'erences in short periods, such as a 24-hour period, but in longer periods this difference will be negligible. That this differential storage exists is shown by Plate XXVI, which presents a graph of the fluctuation in the water table September 100 DIVISION OF WATER RESOURCES 7-15, 1932, in a ground-water pit located a short distance upstream from the lower control and about ten feet from the stream. From this graph it is seen that there would be a small storage differential each day between September 9 and 12, but that this diiferential is almost zero between September 8 and 9 and from September 12 to 15, and that the storage differential over the entire period would be only an extremely small portion of the use of water during the period. As between September 8 and 15, the storage differential is represented by 0.85 inch. Assuming the specific yield to be 8 per cent, this represents a depth of water of 0.068 inch which spread over 2.36 acres — the area between the middle and lower controls — gives a volume of 0.16 acre-inch. The total use between those controls for this period was 7.39 acre-inches. Hence the differential storage over the entire period is only 2.2 per cent of the total use of water for this period of one week, which is no doubt higher than usual as a hot wind was blowing during the early morning hours of September 8. For longer periods, such as a month, the percentage would be considerably less. PLATE . XXVI September 1932 Change in ground water elevation, in inches. 8 th 9 tin loth II th 12 th 13 th 14 th Noon Rising sfac, v\ Fall!r f a stage <--\ /- ^-^ \ / ^ / \J \y Ky V \ vy 1 , 1 V FLUCTUATION IN THE WATER TABLE IN COLDWATER CANYON, SEPTEMBER 7-15, 1932. To obtain the volumes of water passing each control not equipped with a flow recorder it was necessary, in order to attain sufficient accuracy, to take off hourly values from the water-stage recorder charts. Later, when the flow recorders were installed, the daily volumes of water passing each control could be planimetered directly from the flow recorder charts. A section of the discharge curve at the middle control is shown in Plate XXVII. This plate shows the record of discharge at the middle control from August 9 to August 15, 1931. It includes four warm days, August 9, 10, 11, and 15 ; one day on which rain fell, August 12 ; and two cool, cloudy days, August 13 and 14. The eft'ect of evaporation is indicated by a comparison of the evaporation from an evaporation pan, placed in the middle of the stream so that water of the stream entirely surrounded the pan, and the loss between the middle and lower controls. During the period from September 8 to 14, inclusive, 1932, the average depth of evapora- tion from this pan was 0.0076 foot per day. Assuming an average width of stream surface of 3 feet the total volume whicli Mould be evaporated in the length of 2090 feet between the middle and lower WATER LOSSES FROM WET AREAS 101 controls, if the same rate were maintained, would be 0.013 acre-inch per day. Between these controls the average measured loss of water per day durino; this period was 1.06 acre-inches. Therefore the evapo- ration would be only 1.2 per cent of the total measured loss. These values are shown in Table 33 together with the daily comparisons during the period. TABLE 33 COMPARISON OF ESTIMATED LOSS BY EVAPORATION FROM STREAM AND TOTAL LOSS BETWEEN MIDDLE AND LOWER CONTROLS IN COLDWATER CANYON September 8-14, 1932 Date 1932— September 8 September 9 September 10 September 11, September 12 September 13 September 14 Averages Depth of evaporation from tank 2 feet in diameter surrounded by stream, in feet 0.015 .007 .000 .007 .008 .005 .005 .0076 Estimated evaporation from stream in acre-inches' 0.026 .012 .010 .012 .014 .009 .009 .013 Loss between middle and lower controls, in acre-inches 1.44 1.19 .91 .86 1.01 .97 1.01 1.06 Estimated evaporation loss expressed as a percentage of total loss 1.8 1.0 1.1 1.4 1.4 .9 .9 1.2 tank. > Evaporation computed for a stream surface 3 feet wide by 2,080 feet long at same rate as evaporation from 2-foot The true rate of evaporation from the stream would no doubt be less than the rate from the evaporation tank, as the average daily maximum temperature for the period was 2.4 degrees higher in the tank than in the stream. Air and water temperatures for this period are given in Table 34. It can be seen from Plate XX, which shows a typical section of the canyon, that the water surface of this stream is TABLE 34 DAILY MAXIMUM AND MINIMUM TEMPERATURES IN COLDWATER CANYON OF THE AIR, THE STREAM, AND THE WATER IN THE EVAPORATION PAN September 8-14, 1932 Date 1932— September 8 September 9 September 10 September 11 September 12 September 13 September 14 Averages Temperature, in degrees Fahrenheit Water in stream Maximum 68 68 67 66 66 66 65 66.6 Minimum 62 64 60 58 58 58 00 60.0 Water in the evaporation pan Maximum 71 72 69 68 67 68 68 69.0 Minimum 62 64 61 60 59 58 59 60.4 Air Maximum 100 93 86 85 87 85 83 88.4 Minimum 87 81 60 58 60 63 59 66.9 102 DIVISION OF WATER RESOURCES PLATE XXVII August 1931 0.6 0.5 in C --0.3 o c»th 10 -th II th 12 th i?4th 14. th l"i*h ri /' -- -^ \ t V ^ V y \ \ \ /^ - ^ r- / / \ r V 1 \ / 1 / \ / r / ^0.2 / / ' / ii Rain. 21 in. \ noon to 2 1 1 1 1 >M. \ / 0.1 0. i \ / \ i \ / / \ / \ ^ 1 1 1 1 1 1 FLOW AT MIDDLE COLDWATER CANYON CONTROL, AUGUST 9-15, 1931. almost completely shaded and the indicated evaporation rate can not be applied to open areas where the water surface is exposed to the sun. If transpiration is the main factor in causing the daily drop in a stream flow, the demand on the stream for water to take care of the transpiration needs of the vegetation growing in the canyon might be expected to follow a typical rate of transpiration curve. That it does tend to do this is shown by a comparison of a daily cycle of loss in discharge from Coldwater Canj'on to the daily cycle of a typical rate of transpiration curve. A graph of the drop in stream flow occurring at the upper and lower controls is shown in Plate XXVIII-A. Plate XXVIII-B shows a record of the loss of water by evaporation and transpiration on September 11-12, 1930, from a tank of mixed swamp vegetation, chiefly wire rush, tule, and willow at Ontario. The Ontario tank record shows 94 per cent of the loss occurring betAveen 8 a.m and 8 p.m. or between 2| hours after sunrise and 2 hours after sunset, and the peak rate of loss occurring between 1 and 2 p.m. Only 6 per cent of the loss occurs between 8 p.m. and 8 a.m., and the loss between midnight and sunrise is very low. The supply of heat energy available for vaporizing this water comes from the sun, and the insolation reaches a peak at noon and drops to zero at sunset; but there is some storage of heat in the ground and the overlying air, and therefore the cycle of transpiration lags behind the radiation cj^cle. Air temperature is an index of the heat energy available and, in Plate XXVIII-B, it is shown to have a good correlation with the rate of transpiration during the daylight hours. Both of the curves for the drop in stream flow have the same general shape as the rate of transpi- ration curve. The cross-hatched area between the two curves repre- sents the loss of Avater suffered by the stream as it passed from the middle to the lower control. The demand of transpiration first affects the water table under- lying the soil in which the trees are rooted and, as the water table drops, water moves from the stream to replenish the draft. The maxi- mum rate of drop in flow would be expected shortly after the time of maximum transpiration opportunity. The discharge curves shown in WATER LOSSES FROM WET AREAS 103 PLATE XXVIII 0.3 +: o 15 C0.2 O 0 0) (/) ■OA 0 Ll o Uaximum rates of change in ^ in flow past lower control ^rop m flow past ' middle control. A Lu SAM 85 jr 80 c JZ \ Evaporation -franspiraf ion /7/,'^ temperature 8 P.M. B. ; / 75 70 65 a; i_ OJ X! u 60 £ 55 Mdt 4Al;r.~' 8AM. A. DROP IN FLOW IN COLDWATER CANYON, AUGUST 11-12, 1931. B. DAILY EVAPORATION-TRANSPIRATION CYCLE, ONTARIO WILLOW AND REED TANK, SEPTEMBER 11-12, 1930. 104 DIVISION OF WATER RESOURCES Plate XXVII I- A have the maximum rats of change in flow occurring shortly after noon ; that is, there is a point of inflection on each dis- charge curve between 12 noon and 1 p.m. However, an elemental section of the stream passing the upper control at noon will not reach the lower control until approximately 3 p.m. It will lose water continu- ously as it passes down the channel to replenish the draft on the water table caused by transpiration. The maximum rate of loss should occur at approximately the same time at all points on the stream, but the effect of the time taken for each elemental section to move down the canyon is to displace the point of minimum flow to the right, as shown in the graph. For this reason, the loss in flow curve for the middle control, sho-s^ai in Plate XXVIII-A, is moved to the right 45 minutes, the time taken for an elemental section of water to move from the middle to the lower control. The curve of difference in flows, which is a measure of the evaporation and transpiration between controls, rises rapidly to a peak shortly after noon and then, as the water table is recharged, it gradually falls and approaches zero before sunrise of the next day. The position of the water table depends largely on the relation of the rate of use from the water table by the vegetation to the rate of recharge of the water table from the stream. The change in this relation is the chief reason for such fluctuations in the ground water as are shown on Plate XXVI, the water table reaching a maximum level in the morning and a minimum in the afternoon. If the water table is completely recharged at the time of maximum stream flow early in the morning, and there is no transpiration or evaporation at that time, the total flow into the section must equal the total flow from the section. The total flow into the section is the total of the observed surface inflow and any underground inflow, as from hidden springs. The total flow from the section is the total observed surface outflow plus any underground seepage which leaves the section. If there is neither any underground inflow nor any underground seepage, it follows that in the stated case the observed inflow and the observed outflow must be equal. As long as there is no inflow into a section between controls the water table is supplied only from the stream, and therefore the water table will never be higher than the water in the stream. From this it follows that the stream wall never drain the water table and can not gain in flow as it passes through a section where there is no under- ground inflow. The daily maximum and minimum discharges at each of the con- trols for the days of record are given in Tables 35 and 36. An exami- nation of these tables shows that during all the period of record in 1931 and during the periods in 1932 from June 25 to July 26 and from August 19 to November 3 the maximum daily discharge at the lower control never exceeded by any significant amount the combined discharges at the middle and branch controls. From this it follows that there could be no underground inflow between these controls during those periods, unless there was deep percolation as well. It is possible that a combination of underground inflow and deep percolation might result in a daily difference of zero or thereabouts in maximum discharges at the controls, but the deep percolation, if it existed, would be approximately the same for different stages during WATER LOSSES FROM WET AREAS 105 0 OS H z 0 u (t u ^ 0 .J r^ Q O 7 ^ < }J? s u .g w Q o hJ Q O m ^^ < >' o H J_< H — <; 4J 1 0 < % X u V) Q Z < >- < Q SJ o -3 K 2 = ^~ g o S coeocococC'^Tr'^*<**cccoccccec> 5^iO«Dt~-CiO'-<(MCC^»C«Dt^ o a> oj GJ o -OOOOOOOOOOOOO' OOCOOOOOOOOOOOO o :3° T3 fc- a-' J-g g (M O e*3cc =52 CO OS cnoo CO CO e-S OOtOt'-QOOOOiO'^i^OOOiOCOiOtOCMCO'-O^^'^ COCOCOCOeOCOCOCOCO'^COCOCOCOCO'^COCOCOCOCO COCOCOCOCOCOCOCOCO'^COCOCOCOCO'^COCOCOCOCO ejajajoflJGJOcJcooQJuajaiQjQJCJoajajajGJO sssasssssasasaseassaaaac .^J ^J -fcj .*i .*i .»J ,*J ,*J Jj ^J -♦J -fcj -fcj -•;> -*J -t-J -t^ -*^ -** -♦^ ♦^ -•-• -*^ -*^ OG>GJ0JfiJOOQJflJGJCJOCJDaJOO t^^OOOCOt^t^COOO--'^Coc^Oicoi^oO'<*" 03 QO to Oi ooo S " S .s ^-9 J ° II C3 Q OGOCO— C^J'— '05— 'C^iO C^C^COCOCOCQC _C '^ U _C 1 gi 0 o c ■ 1.5 QJ "^ Z) 1-0 0.5 o Da . 1 I.I ilv maximunr 1 ! II III 1^ 1 ^1 1 1, T temperatures at San Bernardino \ 1 1 1 1 1 1 1 1 ■ {\ n^ yi V L/L A 1 J W Sa« Jl ll .f^ 11 U' \ "1 1 1 1 1 1 of wai 1 er be tw( sen Up pet '• and Middle 1 1 1 C( Dntrob n-.n^-' A, /" n /^ — " 1 '\)^ 1 J Li Lt^ JS "^ L If ^ Jse of 1 wate 1 r b >et 1 /veen 1 Mi dd le c and Voy /vet -Cc )ntr 0l5 _/lr ^^ r r' \ ii ^ J L> \ 'V \ yii_i ^ ^ /F \ ■--rn u u^ May June Jurly Auq^. Sept. Oct 1932 USE OF WATER BETWEEN CONTROLS IN COLDWATER CANYON AND DAILY MAXIMUM TEMPERATURES AT SAN BERNARDINO DURING 1932. of water between the upper and middle controls for the months May to October, inclusive. This use is indicated to be 50 acre-inches per 1000 feet of canyon and. since the canyon bottom area averages one acre for each 1000 feet of canyon, the use of water in the canyon bottom is 50 acre-inches per acre. During August, 1932, the average daily loss from the stream between the upper and middle controls per 1000 feet of canyon was equivalent to 0.74 southern California miner's inch, continuous flow. From the graphs on Plate XXIX, a comparison by months can be made of the losses in the two sections of canyon. The average rate of use of water per 1000 feet of canyon between the middle and lower controls was 0.47 acre-inch per day during July, 0.49 acre-inch per day during August, 0.42 acre-inch per day during September, and 0.30 acre-inch per day during October in 1932. Between the upper and middle controls, the average rate of use of water per 1000 feet of canyon was 0.33 acre-inch per day during July, 0.35 acre-inch per day during August. 0.30 acre-inch per day during September, and 0.20 acre-inch per day during October. 8 — 4503 114 DIVISION OP WATER RESOURCES The averag-e rate of use of water ])er acre of canyon bottom fill between the middle and lower controls in 1932 was 0.42 acre-inch per day during July, 0.44 acre-inch per day during August, 0.37 acre-inch per day during September, and 0.26 acre-inch per day during October. Between the upper and middle controls, the average rate of use of water per acre of canyon bottom fill was 0.33 acre-inch per day during July, 0.35 acre-inch per day during August, 0.30 acre-inch per day dur- ing September, and 0.20 acre-inch per day during October. In the upper section, each 1000 feet of canyon has one acre of canyon bottom fill. Loss from Stream Above the Highest Control The highest control on the stream during the 1931 season was the control which later was called the middle control. During the 1932 season the upper control was the highest control on the stream. The losses indicated by the daily cycle in the discharge curves at the middle control in the 1931 season and at the upper control in the 1932 season were evaluated in the following manner. The actual volume passing the control was subtracted from that volume which would have passed the control had a sustained flow occurred throughout the day equal to the average of the maximum flow on the day considered and the maximum of the next succeeding day. This value does not represent all of the loss by evaporation and transpiration occurring in the canyon bottoms above the control. It may, however, be con- sidered as a fair approximation of the loss that might be reclaimed most readily by carrjang the water down the main canyon in pipes. Table 40 shows the amount of water during the days of record in 1931 that TABLE 40 DAILY LOSS OF WATER FROM THE STREAM INDICATED BY DIPS IN DISCHARGE CURVE AT MIDDLE CONTROL IN COLDWATER CANYON August 1, to October 17, 1931 Date Loss above middle control in acre-inches Date Loss above middle control in acre-inches Date Loss above middle control in acre-inches 1931 Aug. 1 *2.02 3.35 1.78 3.33 2,89 3.21 3.27 3.29 3.00 2.88 2.69 *2.47 3.25 3.19 2.98 3.25 3.18 3.15 3.04 3.19 2.98 1.40 2 54 2.27 1931 Sept. 1 Sept. 2 Sept. 5 1 54 *1.64 *1.81 2.34 2.37 1.93 2.05 1.64 2,24 2.19 2.44 1.01 1.32 2.06 1.89 2.22 .62 1.72 1.65 1.74 1.57 *1.70 1931 Oct. 2 Oct. 3 Oct. 4 Oct. 5 1.70 Aug. 2 - 1.68 Aug 3 1.81 Sept. 6 1.82 Aiiff .5 Sept. 7 -- Oct. 6 Oct. 7 1.42 Alicr ^ Sept. 8 - .66 Aue 7 Sept. 9 Oct. 9 .27 Aiiff 8 Sept. 10 Oct. 10 Oct. 11 Oct. 12 .98 Aug 9 Sept. 11 1.24 Aug 10 Sept. 12 1.52 Aug. 11 Sept. 13 Sect. 14 Oct. 13 Oct. 14 1.53 Aug 17 1.45 Auf 18 Sept. 15 Oct. 15 1.30 Aug. 19 Sept. 16-- Oct. 16 Oct. 17 ---- 1.48 Aug 20 Sept. 17 *1.01 Aug 21 Sept. 18 -- Aug. 22 Sept. 19--- Aug. 23 Sept. 26 Aug 24 Sept. 27 --. Aug. 25 Sept. 28 Aug. 26 Sept. 29 Aug 29 Sept. 30 Aug. 30 Aug. 31 - - Average per day (for 2.91 1.82 1.35 •Portion of day only. WATER LOSSES PROM WET AREAS 115 iiiig-ht be reclaimed above tbe middle control, if the water from the larger springs were carried in pipes and the stream bed kept dry. Table 41 similarly shows the amount of water during the days of record in 1932 that might be reclaimed above the upper control, if the TABLE 41 DAILY LOSS OF WATER FROM THE STREAM INDICATED BY DIPS IN DISCHARGE CURVE AT UPPER CONTROL IN COLDWATER CANYON July 1 5, to November 2 1932 Day of month Loss in acre-inch« s July August September October November 1 2.85 2.81 2.81 2.88 2.84 2.71 2.68 2.74 2.62 2.30 2.35 2.40 2.46 2.44 2.59 2.69 2.78 2.71 2.55 2.62 2.60 2.65 2.59 2.50 2.66 2.39 1.42 1.54 1.74 1.25 1.57 1 48 1.56 2.48 1.76 2.04 .32 1.50 .02 1.45 2.05 1.81 1.70 1.66 1.79 1.86 .74 1.30 1.11 1.11 1.33 1.46 1.34 1.50 1.02 1.19 1.33 1.30 1.06 1.04 1.20 1 03 9 2.50 2.57 2.55 2.42 2.29 2.10 2.34 2.12 1.95 .13 3 4 5 6 7 8 9 10 - - 11 12 13 14 15 2.84 2.79 2.64 2.29 2.32 2.72 2.72 2.62 2.62 2.62 2.58 2.69 2.86 2.92 2.88 2.83 2.80 16 1.93 2.38 1.28 .48 1.85 1.97 2.10 2.24 2.20 2.08 17 18 19 20 . . 21 22 23 24 25 26 27 28 - . 29 30 31 . . Average per day 2.69 2.47 2.07 1.39 water from the larger springs were carried in pipes and the stream bed kept dry. There are, however, many small springs in branch canyons or on hillsides from which the water seeps slowly through a mantle of soil toward the main canyon. When there is little or no evaporation and transpiration, water from these small springs reaches the main canyon and contributes to the flow in the main channel, but on warm days the water from these small springs may not reach the main canyon at all, as it may be intercepted and used to meet the transpira- tion needs of the vegetation which has roots in the soil through or over which the water must pass. During periods of increased transpiration, more and more of these small springs are cut off from the main canyon and the maximum flow measured at a control on the main canyon becomes less each succeeding day. When the days are cloudy and cool, transpiration is decreased and the soil reservoirs that have intercepted these flows become filled and water from the smaller springs again reaches the main canyon. Then the maximum flow in the main canyon increases from day to day. This is a factor that operates to cause a 116 DIVISION OF WATER RESOURCES seasonal drop in the discharge to a low point in August and a recovery during September and October before any rain of importance has occurred. October 9, 10, 11, 1931, were cool cloudy days and the transpira- tion loss was very low and the maximum daily flow increased to 0.46 second-foot at the middle control. In contrast to this, August 24, 25, and 26, in the same year, were three days at the end of a long period of hot weather, and on the mornings of August 25, 26, and 27 the maxi- mum flow was only 0.25 second-foot at the middle control. The dif- ference between 0.46 second-foot and 0.25 second-foot, or 0.21 second- foot, represents a loss of water originating in these small springs, but this flow was entirelj- intercepted so that none of the water represented by this value of 0.21 second-foot reached the middle control at any time on August 24, 25, and 26. A flow of 0.21 second-foot is equiva- lent to 5.0 acre-inches per da3\ This is a loss that might be reclaimed if each spring were sought out and developed at its source. The draft on the connected flow measurable by the dip in the discharge curve at the middle control on August 24, 25, and 26 is given in Table 40 and averages 3.1 acre-inches per day. The loss between the middle and lower controls on those three days averaged 1.0 acre-inch per day. This makes a total of 9.1 acre-inches per day, for the average loss per day on August 24, 25, and 26 in 1931, and is chargeable to evaporation and transpiration between the springs, where the water first comes to the surface, and the lower control. The source of the summer flow is within an area of 0.2 square mile between elevations of 3100 and 4250 feet in the stream bed. The drainage area back of the stream bed elevation of 3100 feet is 1.3 square miles and the elevation of the divide ranges from 5200 to 5800 feet. The seasonal precipitation recorded at Alpine at an elevation of 5750 feet was 53.66 inches in 1931-32, yet the first steady spring flow in Coldwater Canyon is below an elevation of 4250 feet. The flow at the lower control was never as great as that measured at the upper control during the period of measurement from July 15 to November 3, 1932. The significance of this fact is that there was no effective yield of water as summer flow from the portion of the water- shed tributary to the stream below the upper control, which portion is 62 per cent of the watershed area above the lower control. Since there was no gradual gain in flow as the stream passed through the 7965 feet of canyon between the upper and lower controls, it indicates that prac- tically all the moisture from rainfall that might have been slowly moving downhill through the soil mantle over this lower portion of the watershed was intercepted by the vegetation before it reached the canyon bottom. COMPARISON OF USE BETWEEN CONTROLS WITH METEOROLOGICAL DATA During the 1932 season records were obtained from an air thermograph, maximum and minimum thermometers, and an atmometer located near the mouth of the canyon, and also from an atmometer located near the lower control in the canyon. Monthly mean maximum and minimum temperatures are shown in Table 42 for the months of record in 1932 at the mouth of the canyon. 4 WATER LOSSES FROM WET AREAS 117 TABLE 42 MONTHLY MEAN MAXIMUM AND MINIMUM TEMPERATURES AT THE MOUTH OF COLDWATER CANYON, AT ALPINE, AND AT SAN BERNARDINO June to October, 1931 and 1932 Temperature in degrees Fahrenheit Month Alpine, United States Weather Bureau, Squirrel Inn Station, elevation, 5,750 feet San Bernardino, United States Weather Bureau Station, ele- vation 1,150 feet Arrowhead Springs near mouth of Cold- water Canyon, elevation 2,000 feet 1931 1931 1932 1932 1931 1931 1932 1932 1932 1932 Mean maxi- mum Mean mini- mum Mean maxi- mum Mean mini- mum Mean maxi- mum Mean mini- mum Mean maxi- mum Mean mini- mum Mean maxi- mum Mean mini- mum June 71.5 85.1 79.2 74.8 71.9 46.5 62.6 60.8 47.6 39.4 74 5 80 6 81.1 83.4 66.9 42.3 51.1 53 6 53.7 41.5 90.5 103.2 100.0 92 3 83.3 55.4 65.0 63.0 54.1 50.0 86.0 92 9 93.7 91.2 82.0 48 4 52.0 51.9 48.7 43.7 July 94.5 92.9 79.9 61.4 September 60.5 October 56.8 . Average June to n(>t.nhpr 76 5 51.4 77.3 48.4 93.9 57 5 89.2 48.9 TABLE 43 LOSS OF WATER FROM ATMOMETERS AT COLDWATER CANYON July 18. to October 24, 1932 Loss in cubic centi- Loss in cubic centi- meters from atmo- meters from atmo- Period meter "A" with full meter "B" under Ratio B/A exposure located near trees in canyon bot- mouth of canyon tom near lower control July 18-Aug. 1 1,077 962 0.89 Aug. 1-Sept. 1 2,274 1,767 .78 Sept. 1-Oct. 1 1.898 1,588 .84 Oct. 1-Oct. 24 1,382 1,013 .73 July 18-Oct. 24 6,631 5,330 .80 Values are also given in Table 42 of the monthly mean maximum and minimum temperatures at the Squirrel Inn and San Bernardino "Weather Bureau stations for June to October, inclusive, during 1931 and 1932. Table 43 gives the use from each of the atmometers during the periods between readings from July 18 to October 24, 1932. For the period from September 7 to 15, 1932, a more intensive study was made of the meteorological data at Coldwater Canyon. An eva])orimeter (described in detail on page 97), a hygro-thermograph, and a second atmometer were placed near the mouth of the canyon in addition to the maximum and minimum thermometers, rain gage, and atmometer already there. Two thermographs, one to record the air temperature and the other to record the temperature of the stream, and an additional atmometer were placed near the lower control in the canyon. There were also installed at the same location an evaporation 118 DIVISION OF WATER RESOURCES pan sunk in the stream channel and completely surrounded by the stream, and a recorder on a ground water pit about 10 feet away from the stream. Readings were taken at all installations throughout this period each day near sunrise, near sunset, and at various other times. Rela- tive humidity was determined with a sling-psychrometer near the mouth of the canyon and at various locations in the canyon. The maximum and minimum discharges at the middle and the lower controls also were carefully checked each morning and evening. PLATE XXX September 1932 UJ COMPARISON OF LOSS OF Vi'ATER FROM EVAPORIMETER AND AIR TEMPERATURE NEAR MOUTH OF COLDWATER CANYON, SEPTEMBER 7-15, 1932. Plate XXX shows the comparison, during the period, of the air temperature near the mouth of the canyon with the evaporation from the evaporimeter at the same location. Note that insolation is the primary causative factor controlling the loss from the evaporimeter, since it is very nearly in phase with the radiant energy cycle and reaches a maximum each day just about noon. The air temperature lags behind and does not reach a maximum generally until around 2 p.m. The daily evaporation from the evaporimeter compared with the daily loss from the atmometers, both in the canyon and at the mouth of the canj^on, is given in Table 44 together with the daily loss between the middle and the lower controls. The record of the fluctuations during this period in the ground water pit has alreadj^ been referred to and is shown on Plate XXVI. The evaporation from the evaporation pan also has been discussed and the dailj^ values given in Table 33. WATER LOSSES FROM WET AREAS 119 TABLE 44 COMPARISON OF LOSS OF WATER FROM ATMOMETERS, EVAPORIMETER, AND LOSS OF WATER BETWEEN MIDDLE AND LOWER CONTROLS September 8-14, 1932 Loss in cubic centimeters from atmometer near mouth of canyon Loss in cubic centimeters from atmometer in canyon Loss in inches from evapo- rimetcr near mouth of canyon Loss in acre-inches from stream between middle and lower controls Per cent of average loss for the week Date Atmometer near mouth of canyon Evapori- meter near mouth of canyon Loss from stream between middle and lower controls 1932 September 8 September 9 September 10 September 11 September 12 September 13 September 14 129 70 45 54 65 61 52 --- 42 54 54 45 44 0 50 .34 .25 .28 .30 .28 .24 1.44 1.19 .91 .86 1.01 .97 1.01 190 103 66 79 96 90 76 160 109 80 89 96 89 77 136 113 86 81 96 92 96 Average 68 .31 1.06 100 100 100 The daily maximum and minimum temperatures of the water, both in the stream and in the evaporation pan sunk in the stream, and the daily maximum and minimum air temperatures in the canyon are given in Table 34. YIELD OF WATER FROM DRAINED SLOPES ON ARROWHEAD MOUNTAIN During the last mile of its course, Coldwater Creek skirts the east slope of Arrowhead Mountain, which may be identified in Plate XIX by the natural outline of an arrowhead on the southwest face of the mountain. The cutting of the main canyon has proceeded more rapidly than that of the side canyons so that the side canyons drop off on a very steep grade as they enter the main channel. This has left excellent bedrock exposures at the lower ends of many of the side canyons and there was therefore an opportunity to observe the yield of water from the drained slope above these bedrock exposures. Plate XXXI is a vieAv of the east slope of Arrowhead Mountain taken from a point across Coldwater Canyon on the divide between that canyon and Strawberry Canyon. The elevation of the trail shown at the bottom of the view is approximately 2300 feet and of the moun- tain peak 3510 feet. Seasonal rainfall records for 1931-32 to February 19 are given in Table 45. On February 19, 1932, each side canyon was explored for evidence of water flowing in its bed. No evidence of any yield of water was found in any of the canyons to the left of the point marked A in Plate XXXI. To the right of the point marked A, every channel had flowing water in it. It may be noted from Plate XXXI that there is a marked change in the density of the vegetation to the right of the line marked A-B. To the right of this line, the vegetation is less dense and there are more rock outcrops than to the left of the line. The elevation of the point marked B is approximately 120 DIVISION OF WATER RESOURCES TABLE 45 PRECIPITATION 1931-32 SEASON Station Distance from Arrowhead Mt. Elevation above sea level Total rain July 1, 1931, to Feb. 19, 1932 ■ Miles Feet Inches San Bernardino (U. S. Weather Bureau) Newmark Reservoir (San Bernardino Water Dept.) 6.5 3.5 4.5 4.5 3.0 0.5 1,150 1,400 1,850 2,700 5,750 2,000 20.87 24 30 Devil Canyon Gate (San Bernardino Water Dept.) _ _ ^ 28 47 Devil Canyon Nursery (U. S. Forest Service) .- 32 76 Alpine (U. S. Weather Bureau Squirrel Inn Station) 53.66 '24 39 ' No record prior to October IS, 1931. 3000 feet. Probably more rainfall was received at the higher eleva- tions and water percolating downward from the higher areas found its way into the channels in which the flow was observed. There was no further rain of importance after February 19 and three weeks later all of the channels had dried up and there was no more flow in them during the season of 1931-32. It therefore appears that the soil mantle on the slopes to the left of the line A-B had sufficient capacity to intercept and hold all of the rain that fell during the 1931-32 season. This amounted to at least 24.39 inches as recorded at Arrowhead Springs Hotel, and in the 19-day period from February 1 to February 19, 11.55 inches fell. It may appear rather astonishing that this large amount of rain coming ■\\dthin a period of 19 days at the end of the 1931-32 rainy season, was held without storm run-off by the soil mantle to the left of the line PLATE XXXI EAST SLOPE OF ARROWHEAD MOUNTAIN DRAINING INTO COLDWATER CANYON. WATER LOSSES FROM WET AREAS 121 A-B. However, the imderljing rock is granite and it has apparently been weathered to considerable depth. The rock was found to be weathered and seamed to depths of 30 feet and more in the road cuts along the new Arrowhead high-gear road opposite the entrance to Arrowhead Springs one mile west of the area. Hoots of chamise were found in seams along the faces of the road cuts as deep as 29 feet below the top of the cut. The capaeit}' of the soil mantle to hold moisture on the slope of a mountain depends, among other things, on the soil depth. If the average thickness of the soil mantle on a 45-degree slope were 2 feet, the equivalent depth for the same volume of soil on a horizontal plane would be 2.8 feet. Rainfall is measured by the amount falling on a horizontal plane and if equivalent depth of the soil mantle on the same plane be considered, it is apparent that the capacity for the storage of water from rainfall as soil moisture on a slope is relatively large. Water from rainfall in its movement downhill after penetrating to bedrock may be intercepted and held in the pockets of deeper soil that lie in the depressions through which the water moves in its progress towards lower elevations. In the canyon bottom, though the rate of loss is high, the area of the canyon bottom fill is but a small portion of the watershed and the actual loss by evaporation and transpiration from the canyon bottom vegetation is less than 2 per cent of the seasonal precipitation falling on the watershed. The larger portion of the precipitation must be accounted for on the drained slopes. Most of the steady spring flow that feeds Coldwater Creek comes from the higher reaches of the canyon above an elevation of 3500 feet where the seasonal precipitation is high. The source of all of the steady summer flow was found to come from within an area of 0.2 square mile between elevations of 3100 and 4250 feet in the stream bed. The area contributing to the surface drainage back of the stream bed elevation of 3100 feet is 1.3 square miles and the elevation of the divide ranges from 5200 to 5800 feet. The first steady stream flow in Coldwater Canyon is found at an elevation of 4250 feet, yet a precipi- tation of 53.66 inches was recorded at Alpine during the 1931-32 season. Alpine is at an elevation of 5750 feet. There is a considerable area over the divide that lies above an elevation of 4250 feet from which the surface drainage waters flow northward. The close proximity of the larger springs to this area of high elevation that receives a relatively large amount of precipitation suggests that a considerable amount of deep seepage must be occurring over this upland area. The results of this investigation point to deep seepage from these upland areas above an elevation of about 3500 feet as the source of most of the summer flow. A more complete study should be made of this problem by tracing the source of all of the summer flow coming from all of the drainage systems radiating from Strawberry Peak. CHAPTER V EVAPORATION FROM FREE WATER SURFACES* In any study of water supply a knowledge of unavoidable losses occurring in transmission and storage is important, and in this connec- tion evaporation from free water surfaces is of primary importance. The rate and amount of evaporation are dependent upon climatological factors and vary with each locality in conformity with atmospheric conditions. Evaporation losses from reservoirs used for storage of W'ater materially reduce the quantities available for domestic, indus- trial and agricultural uses. Although much of such losses can not be prevented, a knowledge of their magnitude and of the factors which influence evaporation is desirable for use in devising means of reducing them to a minimum, in estimating the available supply, and in deter- inining the economic feasibility of a project, taking into consideration the evaporation losses from proposed reservoirs. For these reasons the Division of Irrigation of the Bureau of Agricultural Engineering has been making evaporation studies** in the AVest for many years. Evaporation data are also valuable in estimating consumptive use of water by native vegetation growing in moist areas. Since 1928 the Bureau of Agricultural Engineering has been keeping evaporation records at several stations in cooperation with the State Division of "Water Resources and other agencies also have been making such obser- vations. Not all of these agencies use the same type of evaporation pan, and results from the different types are not ahvays comparable. For this reason, a cooperative key station was established at Baldwin Park in 1932 for the purpose of correlating the data that are being collected by the various organizations and for determining factors that may be used to reduce the observations on various types of evaporation pans to a comparable basis. Heretofore, very few data on evaporation in southern California have been published and it is the purpose of this chapter to bring together such records and make them available for general use. BALDWIN PARK KEY STATION The Los Angeles County Flood Control District, the San Gabriel Valley Protective Association, the Pasadena Water Department, the California State Division of Water Resources, and the United States Geological Survey are cooperating with the Bureau of Agi'icultural Engineering, in conducting this investigation. Three types of evapora- tion pans have been installed at the station : 1. Standard Weather Bureau type of pan, 4 feet in diameter by 10 inches deep, set upon a wooden platform above ground. ! * Prepared by Harry F. Blaney, Irrigation Engineer, Bureau of Agricultural Engineering, United States Department of Agriculture. ** "Evaporation from the Surfaces of AVater and River-bed Materials," by R. B. Sleight (Journal of Agricultural Research. Vol. X, No. 5. July .30, 1917) and "Evaporation from Free Water Surfaces," by Carl Rohwer, IJ. S. Department of Agriculture Technical Bulletin No. 271. (122) WATER LOSSES FROM WET AREAS 123 2. U. S. Bureau of Agricultural Engineering type, 6 feet in diameter bj^ 3 feet deep, set 2.75 feet in the ground. 3. Los Angeles County Flood Control District type, 2 feet in diameter by 3 feet de^p, set 2.75 feet in the ground. The standard Weather Bureau pan is the one most commonly used throughout the west and the one from wliich the majority of records are available. In southern California the Bureau of Agricultural Engineering has used this type of pan at each of its experiment stations. The 6-foot tank set in the ground is used in various localities on the valley floor, while the 2-foot tank is used in the mountain watersheds. Other equipment at the Baldwin Park station consists of a Livingston spherical atmometer, maximum and minimum thermometers, a thermo- graph for recording temperatures, a barograph for barometric pressure, an anemometer for wind movement, and both automatic and standard rain gages. Monthly evaporation records obtained from the three types of pans at the Baldmn Park station are given in Table 46. TABLE 46 MONTHLY EVAPORATION RECORDS AT COOPERATIVE KEY STATION AT BALDWIN PARK, CALIFORNIA, 1932-1933 Depth in inches Month Standard Weather Bureau pan Bureau of Agricultural Engineering pan Los Angeles County Flood Control District pan 1932 1933 1932 1933 1932 1933 2.47 3.49 4.79 5.28 6.89 8.15 9.49 1.89 2.38 3.61 4.16 6.43 6.89 7.75 2 213 February.- -- -.- 3 145 March 4 880 April - - 5 8^5 May 7 750 June ----- 7.26 4.81 4 43 4.06 2.22 9 085 July ----- 8.30 8.02 5.64 5.00 4.23 2.07 9 310 9 395 6.565 5 630 4.805 2.367 10 040 August September November-- December -.- Description of pans: Standard AYeather Bureau pan — 48 inches in diameter by 10 inches deep. Bureau of .Agricultural Engineering pan — 6 feet in diameter by 3 feet deep, set 2.75 feet in the ground. Los .Angeles County Flood Control District pan — 2 feet in diameter by 3 feet deep, set 2.75 feet in the ground. Gage held in center of pan by metal cross bar below water surface. Elevation of station: Approximately 400 feet. Remarks: This station is operated cooperatively by the following agencies: Bureau of .Agricultural Engineering, U. S. Department of Agriculture; Geological Survey, U. S. Department of the Interior; Los Angeles County Flood Control District; Pasadena Water Department: San Gabriel Valley Protective Association; Division of Water Ilesources, Department of Public Works, State of California. It is expected that this investigation will be continued for several years, until sufficient data are available for correlating the evapora- tion records that are being collected by the various agencies. The value of many of these records will be greatly enhanced if the proper coefficients can be determined to reduce the measured los.ses to the equivalent evaporation from a lake surface. It is hoped that eventually every type of pan in common use will be installed at Baldwin Park key station, and that the proper conversion coefficients will be determined. 124 DIVISION OF WATER RESOURCES No definite conclusions should be drawn at this time from the results of the first year's work. However, the data presented in Table 46 indicate that the evaporation loss from the Los Angeles County Flood Control pan is greater than that from the standard Weather Bureau pan at Baldwin Park during 1932. The cause of this result is not apparent at this time as Sleight * found that the loss from a standard Weather Bureau pan was greater than that from his 2-foot pan, but it is possible that the discrepancy is due to differences in con- struction and especially to the use of a cross bar in the Los Angeles pan that was not used in the Sleight type. This cross bar was intro- duced to make possible measurements of depth in the center of the pan. MISCELLANEOUS EVAPORATION RECORDS Evaporation stations maintained by the Bureau of Agricultural Engineering at locations other than Baldwin Park have been previously described in Chapters II and III. In addition to observations of evaporation from standard Weather Bureau pans at the Santa Ana and San Bernardino stations, records were obtained from circular tanks 23 inches in diameter by 32 inches deep, set 30 inches in the ground. Measurements were made with a hook gage in a still well to prevent inaccuracies due to surface move- ment. The normal rate of evaporation from the sunken tank was more uniform than that from the Weather Bureau pan as the water in the tank maintained a more even temperature. The total evaporation, however, was less than that from the pan. Experiments by Sleight* at Denver indicate that evaporation from a similar tank 24 inches in diameter by 3 feet deep, set 2.75 feet in the ground was 86.2 per cent of that from an adjacent standard Weather Bureau pan for the period April to November 1916. This agrees closely with the average ratio of 88.8 per cent derived at Santa Ana and 86.6 per cent at San Bernardino for the three-year period ending April 30, 1932. The difference in depths of the tank at Denver and those in California is probably of no importance, but the difference of one inch in diameter may have had a slight effect on the evaporation. Evaporation data collected by the Bureau of Agricultural Engi- neering at Santa Ana, San Bernardino, Prado, Ontario, and Victorville stations are summarized in Tables 47 to 51, inclusive. A canvass was made for other evaporation records and these are published herewith as Tables 52 to 69, inclusive, through the courtesy of agencies collecting them. * "Evaporation from the Surfaces of Water and River-bed Materials," by R. B. Sleight, Journal of Agi'icultural Research, Vol. X, No. 5, July 30, 1917. WATER LOSSES FROM WET AREAS 125 < U^ < o Z c ? F o b OJ n >J u < U U 00 4-) ■< <0 z ^ •< T) It < H C Z J rs < . ■* w c 1) CQ c < C/3 ai H a c 05 Uj o u u u -1 Oi, 3 O z tm o < H wm < O Oi 3 o > i a ^ JH >> ■-I o X Tl H Tf i:Dcoaccooo-«r-Ooooai-^ t«-> J2 fij o c3 a WJ a 'O ^ c O I o - •? 03 .t-i T3 fi c , o o u ji:'- o g.2 . Sue; t a - ^ A 00 pa = >. ^ 5 « G^ o « 4.:> C > OJ 126 DIVISION OF WATER RESOURCES 00 < 2 " 9' Z Oi o b < U d z 3 o 60 < a Q 2 % ' Z CQ z < H < O u z o H O > H Z o 2 -o C c c 'Eb c < 3 a u 3 4-) Si o Q QO C<3 C^ O O C5 CC O O QO C'l ^^ C^ C^ "^ lO 3 ':0 ■^ O CD (M CC ^f I>- t-H ^ oa . V •n s c 0> S "" S c o Q < CO U5 d 4-) I/) u u ■B .J < < H (A 3 Q CO OS u. 0 3 u u « z 2 ^ H 1 0 n CU T) < 4) > > u J S H z o s G Q C3 B C 1 -^ -* iC CO t^ 00 <© CO OO -* SO Oi CO -- ' • CCOO C»OCO&O^CC040^iiOU?'^OCDCD • a V Q Oa OO »0 OO t^ «-oto 1 .t^!0 ,05-^lOOCOCOCOCOiO'^C-lOOOC— ' ■ r..— *iOtot— coooo^ococo — — fMr^ i':OCO(MGOCO'^r05- !>■ t-~ r* i>- ex; r^ 3 iiOiior-r-cscnO'MtO'^otoiooo - 1 OO OO — Ol CO t^ CO M* — CO O CO r- CO 1 CO CO ■^ CO CiOO lO -* Ol CO ^ 0(M ^ ■ ' t-» t* CO :0 :D CO CO CO ift O i>. CO oo r^ . >> icO'«r--Oi/300-0=Cl-^-ct"C^-osor^^oocO'> 3 ■ COOOcOOt^t-cOC^l-MCOOiCCOiOCvi .co^-coo50coc-COCOCOCOiOCOOira 'CO ?3 1 oooio — dco-«f»o<©r^ooo50^- O ■a o c 3 a 5 O -s. « m C3 . C — ^ ^ 9—4503 130 DIVISION OF WATER RESOURCES o 9^ CO 4-1 rn < •8 U ^ 4-) J ^ C oa () J < - H H m < 3 CQ I O c c X: M C^" c4" C^ c4" Cq CiOiOCOlDCQt^ GOdCC— '^OO"*"— i •a t3 3 « & -n cl n a ^ c Fl B o Oi OS 1 c o ■s O. o 02 ^t^ S 2 c 0 ti k. C^ CD WATER LOSSES FROM WET AREAS 131 < ™ c Z ct 0 CO u. u KH -1 n «< ■>, u u U Q > H- 1 H CO n « u c > o m « CO 4-1 in U H J < c 03 V) E H U t- a 0 o X o UJ u 1 a XI 0 T) a V <; > 4) u 0 >- O J E H Z 0 2 i^ I-^ ^ CO lO oo COOO^OQOOaOt-COOClOOO ioocaeO'- 0 lUii^ e a a 8 .S rt P - !> — I, ■o-Q ^ 1 5? S-2t3 I t« c C o fc- ffl 3 a c — 1^ O X "So O. ** ti 132 DIVISION OF WATER RESOURCES TABLE 56 MONTHLY EVAPORATION RECORDS AT SOUTH HAIWEE RESERVOIR, CALIFORNIA, 1924-1932 Observed by Bureau of Water Works and Supply, City of Los Angeles Month Depth in inches 1924 1925 1926 1927 1928 1929 1930 1931 1932 January *1.68 3.22 *5 32 5.33 9 04 9 30 10.85 9.98 7.10 *3.31 *2.28 *1.68 1.75 2.27 3.19 6.49 6.46 9 15 9.28 7.07 6 35 3.53 2 45 1.24 1 91 1.97 3.73 4.84 6.89 8.00 8.90 6 80 5 50 3.92 3.80 *2.54 *1.75 *3.10 5 76 4.30 6.80 7.00 7.85 7.70 6,72 3.80 1.64 *1.35 *1 00 *1.18 3 39 5.26 5 02 7.36 8.35 6.00 6.25 3 15 2 00 *1.65 n.75 1 94 3.71 4 22 6.10 5 80 8.15 7.11 6 61 4 70 2.50 1 81 n.oo *2.31 3.13 3 67 5.87 5.94 8 00 7.80 6.70 3.17 2.48 *1.13 *1.75 *2.15 2 23 3.13 3 90 7.14 8.00 6.94 6 10 3 56 ♦2.57 *1.00 *1.00 February - *1.52 March 5.10 6 95 May 7.00 June - -- 8.05 July 12.80 Auffust 11.63 September October 8,45 3.95 2.24 1.76 Totals -. --- 69.09 59.23 58 80 57.77 50 61 54 40 51 20 48.47 70.45 Type of pan— Colorado land pan. Description of pan— 3 by 3 by IJ^ feet deep, set in the ground. Elevation of station — 3,800 feet. Record furnished by H. A. Van Norman, Chief Engineer and General Manager. Remarks: 'Portion of record'estimated. TABLE 57 MONTHLY EVAPORATION RECORDS AT FAIRMONT RESERVOIR, CALIFORNIA, 1923-1932 Observed by Bureau of Water Works and Supply, City of Los Angeles Month Depth in inches 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 *2.88 *3.57 5.75 7.31 14.15 15.75 16.67 17.91 14 35 7.70 4.42 *2.91 3.46 4.11 6.92 7.14 9.14 12.16 *17.48 n5.92 *11.02 *7.42 4.20 2.85 3 02 3.02 4.97 4.53 10.58 16.26 18.51 16.47 12.12 8.43 5.75 2.09 3 02 3.82 4 89 7 52 11.31 12.74 16.89 15.34 9.64 8.14 3.99 1.73 2.14 3.58 5.09 7.61 10 51 13.64 16.27 16 44 11.83 7 33 4.12 2.50 2 94 3.24 5.22 6.48 12.25 11.67 18.08 16.08 10.13 7.84 5.51 4.44 2.81 4.10 4.59 8.06 8.79 14.24 17.69 14.92 9.47 6.10 4.54 1.81 2.74 3.13 6.85 7.56 12.12 12.76 18.26 14 27 9 63 6 41 3.42 2.26 2.39 2.67 March 5.98 April - - 7.66 May - - 9.42 14.36 July 17.62 August 16 00 Septennber 12 15 7.63 5.38 3.34 5 70 December 2.24 Totals- ... 113.37 101.82 105.75 99.03 101.06 103.88 97.12 99.41 103.82 Type of pan— Colorado land pan. Description of pan— 3 by 3 by 1}4 feet deep, set in the ground. Elevation of station— 3,050 feet. Record furnished by H. A. Van Norman, Chief Engineer and Genera! Manager. Remarks: 'Portion of record estimated. WATER LOSSES FRO:\I WET AREAS 133 TABLE 58 MONTHLY EVAPORATION RECORDS AT SILVER LAKE RESERVOIR, CALIFORNIA, 1930-1933 Observed by Bureau of Water Works and Supply, City of Los Angeles January. -- Februa^y.- March April May June July August September. October November- December.. Month 1930 7.58 6.21 5.75 4,13 2.93 Depth in inches 1931 4.80 4.74 6.28 5,68 7.01 8.22 7.32 6.10 4 89 3.89 1932 3.43 4.30 5.63 5.50 6.27 7.19 7.52 5.16 4.62 3.49 2.28 1933 2.65 3.72 Type of pan — Floating pan. Description of pan — 30 inches square by 18 inches deep. Elevation of station — Approximately 440 feet. Records furnished by H. A. Van Norman, Chief Engineer and General Manager. TABLE 59 MONTHLY EVAPORATION RECORDS AT LOWER- FERNANDO RESERVOIR, CALIFORNIA, 1930-1933 Observed by Bureau of Water Works and Supply, City of Los Angeles Depth in inches Month Standard Weather Bureau pan Floating pan 1930 1931 1932 1933 1930 1931 9 06 7.54 11.62 8.72 7.51 9.45 11.71 9.76 9.33 8.07 6.23 8.23 February 8.20 8.09 March ......1 8.48 9.37 4.49 6.30 9.72 10.32 8.13 8.64 13.02 6.02 April . . - May . 5.06 Jme . 6.93 july - 8.94 August 8.32 September 8 13 October ..---. 10.97 12 94 10 69 8.25 7.97 6.43 6.37 November 4.65 December. Description of pans: Standard Weather Bureau pan — 48 inches in diameter by 10 inches deep. Floating pan — 30 inches square by 18 inches deep. Elevation of station — .\pproMmate!y 1,140 feet. Records furnished by H. A. \'an Norman, Chief Engineer and General Manager. 134 DIVISION OP WATER EESOURCES TABLE 60 MONTHLY EVAPORATION RECORDS AT CHATSWORTH RESERVOIR, CALIFORNIA, 1931-1933 Observed by Bureau of Water Works and Supply, City of Los Angeles Month January. -- February.. March April May June July August September. October. -- November. December. Total - Depth in inches 1931 10.106 8.260 7.475 5.245 3.686 1932 4.095 3.302 5.890 7.235 7.615 8.410 10.100 10.350 7.355 7.655 7.600 4.310 83.917 1933 4.688 5.425 6.605 5.705 Type of tank — Los Angeles County Flood Control District. Description of tank: 2 feet in diameter by 3 feet deep; set 2.75 feet in the ground. Elevation of station — Approximately 900 feet. Records furnished by H. A. Van Norman, Chief Engineer and General Manager. TABLE 61 MONTHLY EVAPORATION RECORDS AT ENCINO RESERVOIR, CALIFORNIA, 1930-1933 Observed by Bureau of Water Works and Supply, City of Los Angeles Depth in inches Month Standard Weather Bureau pan Floating pan Los Angeles County Flood Control Dis- trict tank 1932 1933 1930 1931 1932 1933 1932 1933 .Taniiarv 4.36 6.19 5.66 4.90 6 07 7,84 9 60 8.91 7.84 5.95 4.79 4.19 "FpKriiarv 5.00 6.85 3.59 4.93 5.22 March 5.14 6.64 6 16 7.65 8.39 10.04 7.10 6.25 5,41 3.39 7.38 May 8.48 9.56 10.16 13.00 8.14 7,58 7.49 3.70 July 9.98 11.14 7.21 6.56 7.15 3.32 . 9.19 7.14 6.47 4.56 3.95 October November Description of pans: Standard Weather Bureau pan — 48 inches in diameter by 10 inches deep. Floating pan — 30 inches square by 18 inches deep. Los Angeles County Flood Control District tank — 2 feet in diameter by 3 feet deep; set 2.75 feet in the ground. Elevation of station — Approximately 1,020 feet. Records furnished by H. A. Van Norman, Chief Engineer and General Manager. WATER LOSSES FROM WET AREAS 135 < a z Q Z <: o' •a: o a m Z 1^ ►J o o Q z ■< o <: o % (1 Ss in ^ Hr^ , r4 ci2 u u J P< CO < ~ as H »£ ►-t «r J M < > u o w IS) < < Q z o H •< b; o > H Z o 2 c o > J3 cd U c on J3 J3 o «Nco:oooascs'^asoooooo O 1 »-• CC o^-^-'j't^t'-r-.ooiooso 00 e^'^4rtia«t^;o»0'^c>a-H CO lO a> A 1-H OOt^^O^-HOO-^co— -icoo •^ CO ^c^co-^-vio — iC'^rroc^'-' CO a» '^ OQ O J O (h oow^-^-^c^r-i^-^tDt^co oo O CflOOO^OiOSOSI^-C^CCOOOS t* .— '-2 o CO — c^c^rocO'*:040Trro 1— ( ■^T'^ — crsoo^— 'oo-^focsico lO CO — t^OiCOOt^CiCiC^CSGO cic-5 — ^oo-^ OS g eoos^ooooo— icuo^as t— o CO ^H — *4cOTr»ct^:c-^coc^^H Tf< K OS ■^ O S coco t>-05 OS Cfl «^ OS 1— I ooo — Oos:ooo:ooo^c-j'^»' 00 — C^CSOSSOCSfM — C^tONCO *o CO (MCci'Tj'-^iCtCOCt-^-^CO*-^ l^ cs lO " *o K ^ -*j U3 CO 1; t^ - Q « O ra no t) «*=• . S >.«>'-' a I. a -3 — « n'-' NTi ■»A lis I c ^- "O OQ o 3 _ C^ 2.S o . § r.2 >. 3 S "S rt o 3 '5 3 .•1 k< O fc. >. » a. 5 136 DIVISION OF WATER RESOURCES TABLE 63 MONTHLY EVAPORATION RECORDS AT PINE CANYON STATION, SAN GABRIEL RIVER, 1930-1933 Observed by the Pasadena Water Department Depth in inches Month Standard Weather Bureau pan Bureau of Agricultural Enginee ring tank 1930 1931 1932 1933 1930 1931 1932 1933 2.844 2.892 6.420 5.832 7.140 7.788 10.368 9.264 7.596 5 436 3.624 1.764 1.956 2.724 5 220 6.324 6.492 7.176 9.756 9 216 7.752 6 312 5 556 2.676 3.120 3.684 5.604 5.340 2.232 2.400 4.992 4.488 5.460 6 384 8.796 7.692 6 300 4.356 2.796 1.416 1 536 1.788 3-888 5 040 5.256 6.216 7.644 7.512 6,168 5,016 4,212 2 028 2.388 Februarv - - 3.012 March - 4 212 3 744 June July October 6.036 5.220 3 156 4,896 4.152 2.760 November - - - Totals 70.968 71.160 57 312 56 304 Description of pan and tank: Standard Weather Bureau pan — 48 inches in diameter by 10 inches deep. Bureau of Agricultural Engineering tank — 6 feet in diameter by 3 feet deep; set 2.75 feet in the ground. Elevation of station— 950 feet, U. S. G. S. Record furnished by C. W. Sopp. TABLE 64 MONTHLY EVAPORATION RECORDS AT LITTLE CIENAGA, CALIFORNIA, 1929-1933 Observed by Los Angeles County Flood Control District Month Depth in inches 1929 1930 1931 1932 1933 January 1.12 2.78 .62 2.53 0.971 0.945 3.816 4.130 4.930 5.110 6.838 6.540 6.475 4.095 3.445 1.045 48.340 1.150 February. 1.691 1.23 1.67 3.120 April May - - - 3.87 3.62 4.12 2.62 3 90 4.85 3.95 3.10 2.80 1.54 July 5.51 4.98 3.40 2.78 2.52 1.71 August 3.96 3.245 2.073 .901 November Total Type of tank — Los Angeles County Flood Control. Description of tank — 2 feet in diameter by 3 feet deep; set 2.75 feet in the ground. Elevation of station — 4,650 feet. Record furnished by E. C. Eaton, Chief Engineer. Remarks: Located 1 mile north of Colbrook Camp. WATER LOSSES FROM WET AREAS 137 TABLE 65 MONTHLY EVAPORATION RECORDS AT BIG DALTON DAM, CALIFORNIA, 1930-1933 Observed by Los Angeles County Flood Control District January February -- March April May June July August September. October November. December.. Totals. Month Depth in inches 1930 10.44 9 61 14 45 9 14 10.22 9.17 5.84 1931 4.66 3.86 8.86 7.74 8 02 9 80 12.76 11.97 11.16 7.32 5.085 3.025 94.260 1932 3.210 2.710 6.020 7.195 7.150 8 410 11.025 11 835 8,855 6.785 7.885 3.100 84.180 1933 4.250 4.350 6.470 Type of tank — Los Angeles County Flood Control, feet in the ground. Elevation of station — 1,500 feet. Records furnished by E. C. Eaton, Chief Engineer. Description of tank — 2 feet in diameter by 3 feet deep, set 2 . 75 TABLE 66 MONTHLY EVAPORATION RECORDS AT PUDDINGSTONE RESERVOIR, CALIFORNIA, 1929-1933 Observed by Los Angeles County Flood Control District January.. - February.. March April May June July August September. October. _- November. December. Month 1929 6 99 7 90 7.73 5 32 Depth in inches 1930 1931 *2.29 *3.25 *2.76 *1.67 *3 60 5.78 4.52 *5 27 *4.64 5.86 6.73 7.29 11.65 10.17 10 52 9.16 7.37 8.66 7 43 6.04 *3 30 *3.74 5.24 *2.33 1932 ♦2.24 *1.61 4.20 5.47 5.50 6.65 9.42 9.30 6.70 6 53 6.76 3.38 1933 3.30 3.88 5 32 5.18 Type of tank — Los Angeles County Flood Control. Description of tank — 2 feet in diameter by 3 feet deep, set 2.75 feet in the ground. Elevation of station — 1,030 feet. Record furnished by E. C. Eaton, Chief Engineer. Remarks: *Incomplete for days of rain. 138 DIVISION OF WATER RESOURCES TABLE 67 MONTHLY EVAPORATION RECORDS AT PACOIMA DAM, CALIFORNIA, 1930-1933 Observed by Los Angeles County Flood Control District January February.-. March April May June July -. August September. October November. December.. Totals. Month Depth in inches 1930 4.85 9 80 9 06 9.29 9.06 6 07 7.10 4.46 1931 9.54 8.58 8.64 7.28 5 93 2.51 74.32 1932 2 330 1.915 5.435 6.565 5 280 7.815 9.285 9.045 7.830 7.290 7.810 3.355 73.955 1933 3.415 4 320 5 640 4 940 Type of tank — Los Angeles County Flood Control. feet in the ground. Elevation of station— 1,900 feet. Records furnished by E. C. Eaton, Chief Engineer. Remarks: Located at mouth of the canyon. Description of tank — 2 feet in diameter by 3 feet deep, set 2.75 TABLE 68 MONTHLY EVAPORATION RECORDS NEAR ACTON (MELLON), CALIFORNIA, 1931-1933 Observed by Los Angeles County Flood Control District Month January February.. March April May June July.. August September. October November. December- Total. Depth in inches 1931 11.38 9.40 6.81 4 325 2.185 1932 2.636 1.945 5.885 6.925 7.795 10.180 13.375 13.980 10.935 7.940 6.490 3.130 91.216 1933 045 415 260 860 Type of tank — Los Angeles County Flood Control. Description of tank — 2 feet in diameter by 3 feet deep, set 2.75 feet in the ground. Elevation of station — 3,100 feet. Records furnished by E. C. Eaton, Chief Engineer. Remarks: Located at North Branch of Escondido Canyon. WATER LOSSES FROM WET AREAS 139 TABLE 69 MONTHLY EVAPORATION RECORDS AT EL SEGUNDO, CALIFORNIA, 1931-1933 Observed by Los Angeles County Flood Control District Month I January -.- February.. March April May - June July - August September. October November. December. . Total. Depth in inches 1931 6.940 5.670 4.434 2.960 1932 3.210 2.845 5.415 6.945 7.525 7.450 7.650 7.435 5.445 5.005 4.395 3.529 66.849 1933 2.875 3 895 5.145 6.085 » Type of tank — Los Angeles County Flood Control. Description of tank — 2 feet in diameter by 3 feet deep, set 2.7 feet in the ground. Elevation of station — 135 feet. Records furnished by E. C. Eaton. Chief Engineer. Remarks: Location at Standard Oil Company. I PART II GROUND WATER SUPPLY AND NATURAL LOSSES IN THE VALLEY OF SANTA ANA RIVER BETWEEN THE RIVERSIDE NARROWS AND THE ORANGE COUNTY LINE By Harold C. Troxell A record of noneconomic loss of water along Santa Ana River from Riverside Narrows to the Orange County line together with an estimate of inflow from ground water above Lower Santa Ana Canyon. TABLE OF CONTENTS PART II Page LETTER OF TRANSMITTAlL. 143 ACKNOWLEDGMENT 144 ■ORGANIZATION, STATE DEPARTMENT OP PUBLIC WORKS 145 ORGANIZATION, UNITED STATES GEOLOGICAL SURVEY 146 GROUND WATER SUPPLY AND NATURAL LOSSES IN THE VALLEY OiF THE SANTA ANA RIVER BETWEEN RIVERSIDE NARROWS AND THE ORANGE COUNTY LINE 147 Description of area 147 Purpose of investigation 14S Classification of bottom land 148 Stream flow records 149 Effect of natural losses on inflow 150 Computation of changes in storage and corrected outflow 155 Computation of natural losses and inflow between Hamner Avenue and Atchison, Topeka and Santa Fe Railway bridge stations 157 Relation of natural losses to evaporation - 168 Natural losses and inflow between Riverside Narrows and the Prado gaging station 168 LIST OF TABLES Table Page 1. Classification of bottom land along Santa Ana River, 1933 148 2. Measurements of Santa Ana River between Riverside Narrows and Prado, 1931 150 3. Natural losses and inflow, in second feet, on Santa Ana River from Hamner Avenue to Atchison, Topeka and Santa Fe Railway bridge 160-167 4. Relation between evaporation and natural losses for area between Hamner Avenue and Atchison, Topeka and Santa Fe Railway bridge on Santa Ana River 169 5. Estimated water supply of the valley of the Santa Ana River above the Prado gaging station, 1930-1932 171 LIST OF PLATES Plate Page I. Map of Santa Ana River between Riverside Narrows and Prado showing area of natural losses, 1933 Between 148-149 II. Typical cross-section of river channel 150 III. Relationship of outflow to transpiration, temperature and evaporation 151 IV. Typical gage-height record 153 V. Location of E series of wells 154 VI. Typical ground-water record 154 VII. Method used in computing changes in ground-water storage Between 156-157 VIII. Relationship between temperature, evaporation and corrected outflow from Hamner Avenue to Atchison, Topeka and Santa Fe Railway 158 IX. Estimated inflow between Hamner Avenue and A., T. and S. F. Ry. Bridge, 1931 159 X. Estimated inflow between Hamner Avenue and A., T. and S. F. Ry. Bridge, 1932 159 XI. Water supply of Santa Ana River above Prado gaging station, 1932 170 (142) LETTER OF TRANSMITTAL Mr. Edward Hyatt State Engineer Sacramento, California Dear Mr. Hyatt : I am transmitting to you for publication by the State a report jirepared by Harold V. Troxell, entitled "Ground water supply and natural losses in the valley of the Santa Ana River between Riverside Narrows and the Orange County line." The report presents the results of an intensive study to determine the quantity of ground water that percolates into this stretch of the valley and is discharged either as surface flow or by evaporation or transpiration of the vegetation in the valley. The report is believed to be of value both because of the use tliat can be made of the data and conclusions which it contains in the further development of the water supply of the drainage basin of the Santa Ana River and because of the contribution which it makes to (liiantitative methods in ground water hydrology. Very truly yours, Washington, D. C, July 31, 1933. Chief Hydraulic Engineer Water Resources Branch, U. S. Geological Survey. (143) ACKNOWLEDGMENT The author wishes to acknowledge the cooperation and help rendered by F. C. Ebert and R. S. Lord, of the United States Geological Survey, and C. A. Taylor, of the Bureau of Agricultural Engineering, United States Department of Agriculture, in preparing this report. Valuable aid was also rendered by the Orange County Flood Control District, through M. N. Thompson, chief engineer, in collecting part of the field data. The report was reviewed by W. G. Hoyt, A. C. Spencer, C. H. Pierce, and 0. E. ]\leinzer, and was edited by B. H. Lane, all of the United States Geological Survev. (144) ORGANIZATION STATE DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES Earl Lee Kelly Director of Public WorTis Edward Hyatt State Engineer The South Coastal Basin Investigation was conducted under the supervision of Harold Conkling Deputy State Engineer 10—4503 ( 145 ) ORGANIZATION UNITED STATES GEOLOGICAL SURVEY WATER RESOURCES BRANCH N. C. Grover Chief Hydraulic Engineer 11. D. McGlashan District Engineer F. C. Ebert Senior Hydraulic Engineer This report was prepared by Harold C. Troxell Associate Engineer (146) GROUND WATER SUPPLY AND NATURAL LOSSES IN THE VALLEY OF SANTA ANA RIVER BETWEEN RIVERSIDE NARROWS AND THE ORANGE COUNTY LINE By Harold C. Troxell * Description of area. One of the most useful streams in southern California is the Santa Ana River. It rises in the heart of the San Bernardino Mountains above San Bernardino and flows westward across the San Bernardino Valley, southwestward through the Jurupa Basin and along the south edge of the Chino Basin, through the lower canyon in the Santa Ana Mountains, and across the coastal plain to the Pacific Ocean near New- port Beach. Flow through this channel from the mountains to the ocean is continuous only during the winter flood periods. The section of the river channel involved in this report extends from Riverside Narrows to the Orange-Riverside County line. South of the Jurupa Mountains and northwest of the city of Riverside the Santa Ana River passes through a granite canyon known as Riverside Narrows. This bedrock obstruction forces most of the water to the surface, forming a stream that flows continuously as far as the intake of the canal companies in Orange County. Most of this water at Riverside Narrows is return water from the irrigated areas around Riverside. According to old settlers the channel was drj^ dur- ing summer periods prior to the irrigation developments. The earlier measurements of discharge at this point showing the increase in dis- charge are given by W. C. Mendenhall in "Hydrology of San Ber- nardino Valley," (U. S. Geol. Survey Water-Supply Paper 142). About 16 miles down stream from Riverside Narrows the Santa Ana River passes through a secondary coast range, the Santa Ana Mountains. These mountains are made up of shale and sandstone and form a barrier that concentrates and forces to the surface most of the underflow. In this 16-mile stretch the Chino Basin drains into the river along the north bank. The mountain streams of this area are exceedingly steep and flow over bare rock. Many of the storms that occur in southern California are violent and, falling on these mountain drainage basins, produce floods that rush across the plains, carrv^ing large quantities of granitic detritus. In this way the Chino Basin has been built up. These great beds of gravel and boulders have a high percentage of voids, and the flood waters passing over them are greatl}^ reduced, if not entireh- absorbed, adding to the supply in the imderground reservoir. The outlet of this underground reservoir is by seepage into the Santa Ana River between Riverside Narrows and Prado and by evaporation and transpiration in the bottom land of this stretch of the river. The velocity with which the water passes through the gravel is very slow, and the water is doubtless delivered to the river valley at a nearly uniform rate. The Santa Ana Mountains and Temescal Basin, which drain into the river along the south bank, undoubtedly make a much smaller contribution, except possibly during storm periods. * Associate Engineer, Water Resources Branch, U. S. Geological Survey. (147) 148 DIVISION OF WATER RESOURCES Between Riverside Narrows and the Prado gaging station the Santa Ana flows tlirough an inner valley or flood channel in most places less than a mile wide, cut in the old alluvial deposits. Flood flows have deposited in this channel very absorptive gravelly material to a depth of 80 to 100 feet. ]\Iost of this bottom land is now over- grown with plant life, as shown on Plate I. Purpose of investigation. The purpose of this investigation was to determine the total quantity of ground water that reaches the valley or flood channel of the river in this area. It may be represented as the water passing the points marked a in Plate II. This quantity of water would be equal to the gain in the flow of the river if the losses by evaporation and transpiration were reduced to zero. Classification of bottom land. The character of the plant cover of the bottom land between River- side Narrows and the Prado gaging station is indicated on Plate I. The various areas on this plate have been computed and the results are given in Table 1. Between Hamner Avenue and The Atchison, Topeka & Santa Fe Railway Bridge there are 2110 acres of river bottom land, classed as the area of natural losses. Throughout this area the water table ranges from ground surface to about 5 feet below it. TABLE 1 CLASSIFICATION OF BOTTOM LAND ALONG SANTA ANA RIVER, 1933 Classification Water surface Swamp plants, sedges, rushes, etc. Hea\'y brush cover Light brush cover. Heavj' tree cover Light tree cover Grass Cultivated Bare sand Total area, acres Hamner Avenue to Atchison, Topeka and Santa Fe Rail- way bridge Per cent 5.5 6.4 7.1 10.1 34.9 1.1 23.7 4.8 6.4 100.0 2,110 Riverside Narrows to Prado gaging station Per cent 5.2 6.0 8.8 11.9 37.6 2.3 18.6 3.4 6.2 100.0 4,040 Howell ^ amply describes part of the area between the RiA-erside Narrows and Prado gaging stations. He classifies the flora as follows : "Submerged aquatics of the ponds include Potamogeton crispus, Zannichellia palustris, Lenina trisulca, and Myriophyllum spicaUom, and the floating flora is com- posed of such widely distributed species as Azolla fllicioloides, Lemna minor, and Wolfiella Ungulata. In the shallow water of the marshes are found Typha angusti- folia, Cyperus melanostacliyus, Eleocharis rostellata, Scirpus validus, Scirpus ameri- canus. Polygonum hydropiperoides, Radicula luisturtinm-aquaticum,, Jussiaea cali- fomica, Oenanthe sarm&itosa, Samolus floribundus, Lycopus aviericanus, Bidens levis, and Helenium puherulum,. A large number of sedges and rushes are found on « Howell, J. T., The Flora of Santa Ana Canyon Region : Madrono, Vol. 1, December, 1929. PLATE I Map of NTA ANA RIVER between Riverside Narrows and Prado showing Area of Natural Losses 1933 WATER SURFACE SWAMP PLANT UFE: TULES, MARSH GRASS, BRUSH, ETC- HEAVY BRUSH COVER GRASS CULTIVATED AREA BARE SAND LIGHT BRUSH COVER HEAVY TREE COVER • MISC MEAS LIGHT TREE COVER SCALE © USG.S. GAC 0 1/4 1 1 1/2 1 1 1 MILES HAMNtR AVE- SANTA ANA RIVER AT HAMNER AVE. Map of SANTA ANA RIVER between Riverside Narrows and Prado showing Area of Natural Losses 1933 1 1 WATER SURFACE fill CRASS ^^ SWAMP PLANT LIFC ^B TULES, MARSH CRASS, BRUSH, ETC' m CULTIVATED AREA tM3 HEAVY BRUSH COVER s BARE SAND V///\ ^(CHT BRUSH COVER EJ^ HEAVY TREE COVER • MISC MEAS SECTION t^ tlGHT TREE COVER o uses. CACINC STATION SCALE , /' , MILCS ■lo03— Bet. pp. 118-145 WATER LOSSES FROM WET AREAS 149 the moist flats of the rivei- bottom, anions which are Ci/pcnts laeviaatus, Cyperus esculcjitus, Elcocharis capitata, Elrocharis acicularis, Elcocharis montana, ticirpun vernus, Carex praegracilis, JuncJis balticus, Juncus hufonius,, Juncus torreyi, Junc^is ruoiUosus, and Juncus xiphioides. Other plants gi-owing on the moist flats with the sedges and rushes are Equisflion funst9, pp. i-105, 1932. MTiite states that the principle underlying this formula was in part suggested by G. E. P. Smith in his earlier work (p. 8). PLATE VII 4503 — Bet. pp. 156-157 PLATE VII ^0.02 ze 410 / *" / o27 / >» / o2« o2< 1 o. a 9 / 4" 330 B° ♦ S Kf7 ♦'• ol5 ol2 ^.5 "7 / r ^ / *27 oO / *26 4l» / o31 / o25 *22*25 .- 5 / >2 ♦ ' oie / o24 c2' o3 o3 1 ♦« »2 «3 *5 J" 1 o" o2l 1 o20 / ol8 .IB Correc tions . SECOND- FEET -i -4 -2 0 +2 +4 te 1 SANTA ANA RIVER 1932 Method used in computing changes in- ground -water storage- Based on the records from well D- 4603— Bet. pp. 156-157 WATER LOSSE.S FRO:\r WET AREAS 157 that the inflow decreased during the period. For this reason, curves were drawn through small groups of consecutive observations, as the change in inflow would be little for short periods. The average slope of these curves indicates that a change in stage of the water table amounting to 0.001 foot represents the equivalent of a change in outflow of 0.11 second-foot. If the changes in stage at well D represent the average for the area, then the average specific yield for the section of the gravel unwatered during the season is about 12 per cent. Using the factor of 0.11 second-foot per 0.001 foot of change in water level, the change in storage for the entire record was converted into second-feet. The daily measured outflow was then corrected for changes in storage. • The term "corrected outflow" as used throughout the remainder of this report represents the measured outflow plus or minus the change in storage. Computations of natural losses and inflow between Hamner Avenue and The Atchison, Topeka and Santa Fe Railway Bridge stations. In discussing the basic formula for the inflow, it was stated that if the inflow remains constant, the outflow plus or minus changes in storage will vary inversely with the natural losses. On Plate VIII are plotted the relations between the daily corrected outflow and the daily evaporation and temperature for July, August, and September, 1932. The figure opposite each point represents the day of the month. The fact that the observations as i3lotted shifted to the right is apparently due to gradual decrease in rate of inflow as the season progressed. The trend of consecutive observations had more to do in the development of the slope of the monthly curves than the mere averaging of the points, because during short periods the inflow would change little, leading only two principal variables — namely, corrected outflow and natural losses. Thus the third variable is practically eliminated, leav- ing a close relation between corrected outflow and temperature or evaporation, as represented by the slope of the curve. Curves similar to those on Plate VIII were also drawn for 1931. The temperature record was obtained from the thermograph record at the Prado evaporation station. A stud}' of the ground water fluctua- tions showed that practically all the transpiration occurred between the hours of 8 a.m. and 4 p.m. each day. For this reason the daily tempera- ture figures here used represent the average temperature for the period of 8 a.m. to 4 p.m. The data seem to indicate that little or no trans- piration occurs in this area when the average daily temperature is below 60°. If the natui'al losses in this area varied in direct pro- portion with the temperature above 60°, then for each 10° more than 60° the loss would have amounted to 7.7 second-feet in 1931 and 8.0 second-feet in 1932. For the period in 1931 the records from the evaporation pan at Prado were used in plotting the relation of evaporation to corrected outflow. In 1932, however, 0T\dng to imperfect operation of the apparatus, the daily evaporation record at Prado was not entirely satisfactory. For this reason, the record from the evaporimeter at Pomona, operated by C. A. Taylor, of the Bureau of Agricultural Engineering, was used for 1932. This evaporimeter is less than 15 miles from the Santa Ana River area, and the evaporation there should WATER LOSSES FROM WET AREAS 157 that the inflow decreased during the period. For this reason, curves were drawn through small groups of consecutive observations, as the change in inflow would be little for short periods. The average slope of these curves indicates that a change in stage of the water table amounting to 0.001 foot represents the equivalent of a change in outflow of 0.11 second-foot. If the changes in stage at well D represent the average for the area, then the average specific yield for the section of the gravel unwatered during the season is about 12 per cent. Using the factor of 0.11 second-foot per 0.001 foot of change in water level, the change in storage for the entire record was converted into second-feet. The daily measured outflow was then corrected for changes in storage. • The term "corrected outflow" as used throughout the remainder of this report represents the measured outflow plus or minus the change in storage. Computations of natural losses and inflow between Hamner Avenue and The Atchison, Topeka and Santa Fe Railway Bridge stations. In discussing the basic formula for the inflow, it was stated that if the inflow remains constant, the outflow plus or minus changes in storage A^all vary inversely with the natural losses. On Plate VIII are plotted the relations between the daily corrected outflow and the daily evaporation and temperature for Julj^ August, and September, 1932. The figure opposite each point represents the day of the month. The fact that the observations as plotted shifted to the right is apparently due to gradual decrease in rate of inflow as the season progressed. The trend of consecutive observations had more to do in the development of the slope of the monthly curves than the mere averaging of the points, because during short periods the inflow would change little, leaving only two principal variables — namely, corrected outflow and natural losses. Thus the third variable is practically eliminated, leav- ing a close relation between corrected outflow and temperature or evaporation, as represented by the slope of the curve. Curves similar to those on Plate VIII were also dra^^ii for 1931. The temperature record was obtained from the thermograph record at the Prado evaporation station. A study of the ground water fluctua- tions showed that practically all the transpiration occurred between the hours of 8 a.m. and 4 p.m. each day. For this reason the daily tempera- ture figures here used represent the average temperature for the period of 8 a.m. to 4 p.m. The data seem to indicate that little or no trans- piration occurs in this area when the average daily temperature is below 60°. If the natui*al losses in this area varied in direct pro- portion with, the temperature above 60°, then for each 10° more than 60° the loss would have amounted to 7.7 second-feet in 1931 and 8.0 second-feet in 1932. For the period in 1931 the records from the evaporation pan at Prado were used in plotting the relation of evaporation to corrected outflow. In 1932, however, owing to imperfect operation of the ap]iaratus, the daily evaporation record at Pi'ado was not entirely satisfactory. For this reason, the record from the evaporimeter at Pomona, operated by C. A. Taylor, of the Bureau of Agricultural Engineering, was used for 1932. This evaporimeter is less than 15 miles from the Santa Ana River area, and the evaporation there should 158 DIVISION OF WATER RESOURCES PLATE VIII < _ ^ q; 6Vi 90" JULY /: SEPT z • o !< IT o a. 3 SEPT CORRECTED OUTFLOW CORRECTED OUTFLOW SANTA ANA RIVER 1932 Relationship between Temperature, Evaporation and Corrected Outflow from Hamner Ave. to A.T&S.F Ry. vary directly v;^itli the evaporation at Prado. The 1931 data (Prado) seem to indicate that for each 0.10 inch of evaporation from the stand- ard Weather Bureau gage the corrected outflow is reduced 6.0 second- feet. The 1932 data (Pomona) gave 6.3 second-feet for each 0.10 inch of evaporation from the evaporimeter. Next, the relation of the transpiration at well D to the corrected outflow was determined by the use of the formula (24r ± s), taken from the equation q = y (24r ±: s) . The results showed that for each 0.10 foot of ground water transpired, as computed by the formula (24r ±: s), there was a loss of 15.4 second-feet in the corrected outflow in 1931 and 17.6 second-feet in 1932. From the data determined from Plate VTII and similar graphs Table 3 has been developed. This table gives the estimated inflow between the gaging stations at Hamner Avenue and The Atchison. Topeka and Santa Fe Railway Bridge. Column A represents the daily measured outflow from the area, that is, the gain in the flow of the river between the two gaging stations. The daily corrected outflow^ (outflow ± change in storage) is given in column B. If the natural losses in the area varied in direct proportion to the transpiration recorded at well D, the figures in column C represent these losses in second-feet. Then hy adding columns B and C, the daily inflow is determined. Likewise, columns D and E represent the natural losses in the area if evaporation and temperature, respectively, are taken as indicators WATER LOSSES FROM WET AREAS 159 of these losses. After these daily figures of natural losses were obtained, the means for each 5-day period were determined for each of the three methods. Then these results were in turn averaged. The addition of the natural losses to the corrected outflow gives the inflow to the area. The data given in Table 3 have been plotted on plates IX and X. The estimated inflow represents the amount of water passing the points marked ^ on Plate II, or the outside edge of the area of natural losses. On plates IX and X the difference between the graphs marked ' ' mean PLATE IX llii «.-♦■' tt fri SANTA ANA RIVER - 193 Estimated Inflow between Hamner Ave. and AT. &S.F. Ry. Bridge §MEAN INFLOW MEASURED OUTFLOW CORRECTED OUTFLOW JULY S 10 IS 20 25 • BASED ON TEMPERATURE AT PRADO * BASED ON EVAPORATION AT PRADO ♦ BASED ON WELL 0 ! AUGUST 10 15 20 25 I SEPTEMBER 10 15 20 25 PLATE X -T !♦' ^^f :>* ♦r^». tA I ♦' f-n :e: SANTA ANA RIVER - 1932 . Estimated Inflow between Hamner Ave. and A-T&S.R Ry. Bridge "® MEAN INFLOW ® MEASURED OUTFLOW © CORRECTED OUTFLOW I JULY I I 5 10 15 20 25 ♦ BASED ON TEMPERATURE AT PRAOO ♦ BASED ON EVAPORATION AT POMONA ♦ BASED ON WELL 0 I 31 AUGUST I Jfi >i 20 25 -il. 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Qj Qj Qj ■ 00 OO^ :i ^ O 00 OO ^Ht-r^oo c^ »— 1 CO ^O 00 4f5 CM »-H 05 OSiO O CO C CO CO CO CO CO CO 168 DIVISION OF WATER RESOURCES inflow" and ''measured outflow" g'ives the quantity of water con- sumed in the area of natural losses. Tlie inflow has been plotted for every da.y b,y use of the three methods on these plates. ]\Iost of the apparent irregularities during Aug'ust and September, 1931, were due to surface run-off from rainfall, which could not be evaluated. The true relation holds only when all tlie water comes from subsurface sources. Relation of natural losses to evaporation. In order to make the data computed in Table 3 applicable else- where on the Santa Ana River, the natural losses over the area were determined as a function of evaporation. The resvilts are given in Table 4, in which the natural losses for each 5-day period have been converted into acre-feet. The average loss in feet over the whole area was computed by dividing the losses in acre-feet by the area in acres. This average was compared with the evaporation from a standard "Weather Bureau pan at Prado for the same periods, expressed in feet, and the ratio computed. This ratio gives the losses as a percentage of evaporation. For example, for the period July 1-5, 1931, the natural losses amounted to 0.109 foot, or 61 per cent of the evaporation from a standard Weather Bureau pan for the same period. The means of these percentages were computed for the three months in both 1931 and 1932. They were 68 per cent for 1931 and 64 per cent for 1932. The average for the two seasons was 66 per cent. These ratios do not, however, apply w^here the natural losses are compared to evaporation from a reservoir or other relatively large free water surface. By using the coefficient of 1.427 determined by Rohwer ■'' for the correction of the standard pan record, the natural losses for 1931 and 1932 are found to be nearly equal to the evaporation from a reservoir or other large free water surface. Natural losses and inflow between Riverside Narrows and the Prado gaging station. Between the gaging stations at Riverside Narrows and Prado there is 4040 acres of land subject to substantial natural losses. By means of the coefficient determined in the preceding tables, the natural losses within this area were computed and converted into acre-feet for each 5-day period from January to November, 1932. The results of these computations are expressed graphically on Plate XI. A check on the computations for inflow for the area above the Prado gaging station was made by using the data collected at The Atchison, Topeka and Santa Fe Railway Bridge for the period May to November. The area of natural losses above this station is 3580 acres. With the coefficient of 66 per cent the natural losses were computed from the evaporation pan record at Prado. The addition of these losses to the flow at the railway bridge gaging station gave the total inflow for the area between Riverside Narrows and the railway bridge. These results have been plotted on the graph in the form of a dotted line. The 2| miles of river channel between The Atchison, Topeka and Santa Fe Railway Bridge and the Prado gaging stations is cut through " Rohwer, Carl, Evaporation from free water surfaces : U. S. Dept. Agri., Bull. 271, 1932. WATER LOSSES FROIM WET AREAS 169 TABLE 4 RELATION BETWEEN EVAPORATION AND NATURAL LOSSES FOR AREA BETWEEN HAMNER AVENUE AND THE ATCHISON TOPEKA AND SANTA FE RAILWAY BRIDGE ON THE SANTA ANA RIVER (.'\rea, 2,1 10 acres) Natural losses Evaporation at Prado Date Mean (second-feet) Acre-feet Feet Inches Feet Ratio 1931— July 1- 5 July 6-10. July 11-15 July 16-20 July 21-25 July 26-31 .Aug. 1-5 Aug. 6-10 Aug. 11-15 .Aug. 16-20 .■^ug. 21-25 Aug. 26-31 Sept. 1- 5... Sept. 6-10 Sept. 11-15 Sept. 16-20 Sept. 21-25 Sept. 26-30 23 3 20.5 21.4 21.7 23.8 23.4 19.5 19.4 13.7 21.2 26.5 20.0 14.4 18.6 15.3 12.6 15.1 16.3 231 203 212 215 236 279 193 192 136 210 263 238 143 184 152 125 150 162 0 109 .096 .100 .102 .112 .132 .092 091 .064 .100 .125 113 .068 .087 .072 .059 .071 .077 2.12 1.76 1.80 1.74 1.92 2.22 1 57 1.70 1.10 1.71 2 24 L72 1 12 1 57 1 35 1.07 1.07 1.56 0.178 .147 .150 .145 .160 .185 .131 .142 .092 .142 .187 .143 .093 .131 .112 .089 .089 .130 0.61 .65 .67 .70 .70 .71 .70 .64 .70 .70 .67 .79 .73 .66 .64 .66 .80 .59 Mean .68 1932^ July 1-5 July 6-10 July 11-15 July 16-20 July 21-25 July 26-31 Aug. 1- 5 Aug. 6-10 Aug. 11-15 .Aug. 16-20 Aug. 21-25 Aug. 26-31 Sept. 1- 5 Sept. 6-10 Sept. 11-15 Sept. 16-20 Sept. 21-25 Sept. 26-30 15.3 16,5 17.8 17.4 18.3 20.8 23.2 17.9 14.3 22.5 24.3 14.8 20.5 20 3 14.0 10.7 12.0 8.7 152 164 177 173 182 248 230 178 142 224 241 176 204 201 139 106 119 86 0 072 078 .084 .082 ,086 .118 109 ,084 067 .106 114 083 097 .095 .066 .050 056 .041 i:362 1.565 1 571 1.528 2.056 2.203 2.205 1.578 1.112 1.980 2.085 1.523 1.622 1.327 1.225 .978 1.004 .884 0.114 .131 .131 .127 .172 .184 .184 .132 .093 .165 .174 .127 .135 .110 .102 .082 .084 .074 0.63 .60 .64 .65 .50 .64 .59 .64 .72 .64 .65 .65 .72 .86 .65 .61 .67 .55 Mean . .64 the Santa Ana Mountains. There are no live streams feeding the river in this section. If there is little inflow during the summer between these stations, the inflow for the area above the railway bridge gaging station should be nearly the same as that above the Prado gaging station. Plate XI shows that the two sets of figures for inflow agree remarkably well, the decrease in stream flow between the two stations being about equal to the computed natural losses. One purpose of this plate is to show the extent of the losses between Riverside Narrows and the Prado gaging station. Of an inflow which was computed to be 48.5 second-feet, only 12.8 second-feet left the area as surface Avater during the 5-day period August 21-25, 1932. During the period August 1-5, 1930, only 5 second-feet were recovered from an inflow equally great. 170 DIVISION OF WATER KESOURCES PLATE XI WATER SUPPLY of SANTA ANA RIVER above PRADO GAGING STATION 1932 In order to show more clearly the disposition of all the rising- water above Prado, Table 5 was prepared. This table shows the esti- mated water supply above the Prado gaging station for two seasons, 1930-31 and 1931-32. The natural losses were computed, based on the evaporation pan record collected at Prado, except for three months, October, 1930, and February and May. 1932. During these months the record at Prado was incomplete. For the month of October, 1930, the record collected by the Bureau of Agricultural Engineering at Santa Ana was used. The record collected by the same bureau at Pomona was used for the months of February and May, 1932. During the season of 1930-31 there was very little storm run-off due to rainfall, consequently the main source of the water passing the Prado gaging station was from the ground water inflow. Table 5 shows that of the 74,900 acre-feet of inflow into the area above Prado for this season, 17,500 acre-feet, or 23.4 per cent, were consumed by the natural losses in this area. If the water of the Santa Ana River is more A^aluable at any one period of the year than another, it is during the summer irrigation season. During this period the entire flow of the river is diverted by the Santa Ana Valley Irrigation and Anaheim Union water companies. To augment this supply additional water is pumped along the canal systems in Orange County. An inspection of Table 5 shows that for the months of ]\Iay to September, 18,090 acre-feet entered the valley or flood channel of the Santa Ana River between Riverside Narrows and Prado during the season of 1930-31. Of these 18,090 acre-feet, 10,180 acre-feet were consumed by natural losses. This represents a loss of 56 per cent. For the same period during 1931-32, 18,280 acre- feet entered the flood channel of the river. During this season 9790 acre-feet were consumed by natural losses, or a loss of 54 per cent. WATER LOSSES FROM WET AREAS 171 Q. 3 oooooooooooo oooooooooooo « S O *3t3 a? QO !-«• m CD «-* o 03 •S.2 & o 00-^>03 ooooooo OOiOifttCOOOOOOO ^ ^ ^ ^ cS oS cS -i-^ ■^ C3-T3 oocor^cot^oot^ociOO"-:}* »0'-'OC<»C0t— C^Oi— "'-'t^C^ oo<=>ooc?ooooo C^" C^C« CC »C CO C^CS '-^ i-T oooooooooooo i-HC^OiCi— tOiCT-COCDOOOr- OO OS •-< o t- 1^ c^ '-t »— ' oi r* •rZ O « c:'OC'Ooc5 ';000*->^)0»CCMOCDC1CC-H !m' c^ itT CO re ci ci" c^r ^-T — ^ ^ ■a "- • C3 13 S^: oor^ccic*— '^-ificoc^oooi^ r^ocx)OicC'^C5icco"^iO'-H C3 o - "■ " — fc-i rt ' " g 3^ £^ >.g ^ ■g a 1 _g a a ^3^ ^"€ f' S 3 ■ "' CO ri r^ ei -^ OS ii ^ ^ C3 " •^ "-ri 3 3 -i « CO ° ^ 5 g^ S'C g-S ^M-g. 172' DIVISION OF WATER RESOURCES Utilization of Water Supply. The water which under natural conditions is consumed by uneco- nomic plant life could in large part be recovered by pumping from wells, Avhereby the ground water table would be drawn down below the root zone. The installation of pumps in this area would make available the large underground reservoir that now lies unused. The storage in this underground reservoir, as well as the summer inflow, could be drawn upon to meet the fluctuating demands for irrigation. During the winter the underground reservoir would be replenished by the inflow from the sides and also by at least some of the storm run-off that may otherwise be wasted into the ocean. PUBLICATIONS DIVISION OF WATER RESOURCES PUBLICATIONS OF THE DIVISION OF WATER RESOURCES DEPARTMENT OF PUBLIC WORKS STATE OF CALIFORNIA When the Department of Public Works was created In July, 1921, the State Water Commission was succeeded by the Division of Water Rights, and the Department of Engineering was succeeded by the Division of Engineer- ing and Irrigation in all duties except those pertaining to State Architect. Both the Division of Water Rights ind the Division of Engineering and Irrigation functioned until August, 1929, when they were consolidated to form the Division of Water Resources. STATE WATER COMMISSION First Report, State Water Commission, March 24 to November 1, 1912. Second Report, State Water Commission, November 1, 1912 to April 1, 1914. •Biennial Report, State Water Commission, March 1, 1915, to December 1, 1916. Biennial Report, State Water Commission, December 1, 1916, to September 1, 1918. Biennial Report, State Water Commission, September 1, 191S, 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— Basic Data, 1923-1926. 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. • Reports and Bulletins out of print. These may be borrowed by your local library from the California State Library at Sacramento, California. ( 174 ) •Bulletin No. •Bulletin No. Bulletin No. Bulletin No. Bulletin No. Bulletin No. •Bulletin No. •Bulletin No. Bulletin No. •Bulletin No. Bulletin No. Bulletin No. LIST OF PUBLICATIONS 175 DIVISION OF WATER RESOURCES Including Reports of the Former Division of Engineering and Irrigation 1 — California Irrigation District Laws, 1921 (now obsolete). 2 — Formation of Irrigation Districts, Issuance of Bonds, etc., 1922. 3 — Water Resources of Tulare County and Their Utilization, 1922. 4 — Water Resources of California, 1923. 5 — Flow in California Streams, 1923. 6 — Irrigation Requirements of California Lands, 1923. 7 — California Irrigation District Laws, 1923 (now obsolete). S — Cost of Water to Irrigators in California. 1925. 9 — Supplemental Report on Water Resources of California, 1925. 10 — California Irrigation District Laws, 1925 (now obsolete). 11 — Ground Water Resources of Southern San Joaquin Valley. 1927. in No. 12 — Summary Report on the Water Resources of California and a Coor- dinated Plan for Their Development. 1927. Bulletin No. 13 — The Development of the Upper Sacramento River, containing U. S. R. S. Cooperative Report on Iron Canyon Project, 1927. Bulletin No. 14 — The Control of Floods by Reservoirs, 192S. •Bulletin No. 18 — California Irrigation District Laws, 1927 (now obsolete). ♦Bulletin No. 18-A — California Irrigation District Laws, 1929 Revision (now obsolete). Bulletin No. 18-B — California Irrigation District Laws, 1931 Revision (now obsolete). Bulletin No. 18-C — California Irrigation District Laws, 1933 Revision. Bulletin No. 19 — Santa Ana Investigation, Flood Control and Conservation (with packet of maps). 192S. Bulletin No. 20 — Kennett Reservoir Development, an Analysis of Methods and Extent of Financing by Electric Power Revenue, 1929. Bulletin No. 21 — Irrigation Districts in California, 1929. Bulletin No. 21-A — Report on Irrigation Districts in California for the Year 1929. Bulletin No. 21-B — Report on Irrigation Districts in California for the Year 1930. Bulletin No. 21-C — Report on Irrigation Districts in California for the Year 19 31. (Mimeographed.) Bulletin No. 21-D — Report on Irrigation Districts in California for the Year 1932. (Mimeographed.) Bulletin No. 22 — Report on Salt Water Barrier (two volumes). 1929. Bulletin No. 23 — Report of Sacramento-San Joaquin Water Supervisor, 1924-1928. Bulletin No. 24 — A Proposed Major Development on American River, 1929. Bulletin No. 25 — Report to Legislature of 1931 on State Water Plan, 1930. Bulletin No. 26 — Sacramento River Basin, 1931. Bulletin No. 27 — Variation and Control of Salinity in Sacramento-San Joaquin Delta and Upper San Francisco Bay, 1931. Bulletin No. 28 — Economic Aspects of a Salt Water Barrier Below Confluence of Sacramento and San Joaquin Rivers, 1931. Bulletin No. 28-A — Industrial Survey of TTpper San Francisco Bay Area, 1930. Bulletin No. 31— Santa Ana River Basin, 1930. Bulletin No. 32 — South Coastal Basin, a Cooperative Symposium, 1930. Bulletin No. 33 — Rainfall Penetration and Consumptive Use of Water in Santa Ana River Valley and Coastal Plain, 1930. Bulletin No. 34 — Permissible Annual Charges for Irrigation Water in Upper San Joaquin Valley, 1930. Bulletin No. 35 — Permissible Economic Rate of Irrigation Development in California. 1930. Bulletin No. 36 — Cost of Irrigation Water in California, 1930. Bulletin No. 37 — Financial and General Data Pertaining to Irrigation, Reclamation and Other Public Districts in California, 1930. Bulletin No. 38 — Report of Kings River Water Master for the period 1918-1930. Bulletin No. 39 — South Coastal Basin Investigation, Records of Ground Water Levels at Wells, 1932. Bulletin No. 40 — South Coastal Basin Investigation, Quality of Irrigation Waters, 1933. Bulletin No. 41 — Pit River Investigation, 1933. Bulletin No. 42 — Santa Clara Investigation, 1933. • Reports and Bulletins oiit of print. Tliese may be borrowed by your local library from the California State Library at Sacramento. California. 176 LIST OF PUBLICATIONS Bulletin No. 43 — Value and Cost of Water for Irrigation in Coastal Plain of South- ern California, 1933. Bulletin No. 44 — ^Water Losses Under Natural Conditions from Wet Areas in Southern California, 1933. Biennial Report, Division of Engineering and Irrigation, 1920-1922. Biennial Report, Division of Engineering and Irrigation, 1922-1924. Biennial Report, Division of Engineering and Irrigation, 1924-1926. Biennial Report, Division of Engineering and Irrigation, 1926—1928. PAMPHLETS Act Governing Supervision of Dams in California, with Revised Rules and Regula- tions, 1933. Water Commission Act with Amendments Thereto, 1933. Rules, Regulations and Information Pertaining to Appropriation of Water in Cali- fornia, 1933. Rules and Regulations Governing the Determination of Rights to Use of Water In Accordance with the Water Commission Act. 1925. Tables of Discharge for Parshall Measuring Flumes. 192S. General Plans, Specifications and Bills of Material for Six and Nine Inch Parshall Measuring Flumes. 1930. COOPERATIVE AND MISCELLANEOUS REPORTS •Report of the Conservation Commission of California, 1912. •Irrigation Resources of California and Their ITtilization (Bui. 254. OflSce of Exp U. S. D. A.) 1913. •Report, State Water Problems Conference, November 25, 1916. •Report on Pit River Basin. April. 1915. •Report on Lower Pit River Project, July, 1915. •Report on Iron Canyon Project, 1914. •Report on Iron Canyon Project, California, May, 1920. •Sacramento Flood Control Project (Revised Plans), 1925. Report of Commission Appointed to Investigate Causes Leading to the Failure of St. Francis Dam, 192S. Report of the California Joint Federal-State Water Resources Commission, 1930. Conclusions and Recommendations of the Report of the California Irrigation and Reclamation Financing and Refinancing Commission, 1930. •Report of California Water Resources Commission to the Governor of California on State Water Plan, 1932. ♦Booklet of Information on California and the State Water Plan Prepared for United States House of Representatives' Subcommittee on Appro- priations, 1931. •Bulletin on Great Central "Valley Project of State Water Plan of California Prepared for United States Senate Committee on Irrigation and Reclama- m tion, 1932. f * Reports and Bulletins out of print. These may be borrowed by your local library from the California State Library at Sacramento, California. I 4503 1-34 IM 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. *UG 2 7 1964 M. juiM i 1961 DUE J UN « 1971 APR 2 0 l' APR0 6 1937 RECEIVED APR 0 z PHYS SC! LIBRARY ^ 1999 flAV ^j 1999 RE CO I RECEIVED MAY 2 h 1999 PSL Book Slip-25ni-7,'53(A8998s4) 458 PHYSICAL SCIENCES TC&Z4- C2 "71^. 44-4; LIBRARY UNIVERSITY OF CALIFORNIA DAVIS 111607