Phy sci a Emgt C2 A2 1 ,^. 1 T?r IPORNTa THE RESOURCES AGENCY OF CALIFORNIA partment of Wa ter Resources BULLETIN No. 101 1^ <:.\ ' DESERT AREAS OF SOUTHEASTERN CALIFORNIA LAND AND WATER USE SURVEY, 1958 JANUARY 1963 EDMUND G. BROWN Governor State of California WILLIAM E. WARNE Administrafor The Resources Agency of California and Direclor Department of Water Resources state ot California THE RESOURCES AGENCY OE CALIFORNIA Department of Wa ter Resources BULLETIN No. 101 DESERT AREAS OF SOUTHEASTERN CALIFORNIA LAND AND WATER USE SURVEY, 1958 JANUARY 1963 EDMUND G. BROWN Governor State of California t*ri'.-~-..^iTy OP CALIFORNIii; WILLIAM E. WARNE Administrator The Resources Agency of California and Director Department of Water Resources TABLE OF CONTENTS Page LETTER OF TRANSMITTAL vili ACKNOWLEDGMENT X ORGANIZATION xi CHAPTER I. INTRODUCTION 1 Authorization 2 Scope of Investigation and Report 3 Related Investigations and Reports 5 CHAPTER II. AREA OF INVESTIGATION 9 Climatic Conditions 9 Cultural Development 10 Hydrographic Units 13 Death Valley Unit (6-10) 15 Mojave River Unit (6-11) 1? Antelope Valley Unit (6-12) 22 Twentynine Palms Unit (7-l) 25 Coachella Valley Unit (7-2) 27 Salton Sea Unit (7-3) 30 Imperial Valley Unit (7-^) 31 Colorado River Unit (7-5) 3^ Lanfair Valley Unit (7-6) 36 CHAPTER III. LAND USE 39 Methods and Procedures 39 Categories of Land Use ^1 iii Page Results of Land Use Survey kh Change in Land Use h8 Death Valley Unit (6-10) 1«8 Mojave River Unit (6-11) 50 Antelope Valley Unit (6-12) 50 Twentynine Palms Unit (7-l) 50 Coachella Valley Unit (7-2) 51 Salton Sea Unit (7-3) 51 Imperial Valley Unit (7-^+) 51 Colorado River Unit (7-5) 52 Lanfair Valley Unit (7-6) 52 Supplemental Resurveys of [■^iltiple Cropped Areas 52 CHAPTER IV. WATER USE 59 Definition of Water Use 59 Methods of Estimating Water Use 60 Unit Values of Water Use 61 Urban and Suburban Water Use Values 62 Irrigated Agriculture Water Use Values 64 Net Water Use 6k CHAPTER V. SUMMARY AND CONCLUSIONS 71 Summary 71 Conclusions 72 iv TABLES Ta^)le No. Page 1 Population of Principal Urbaji Centers, Southeastern Desert Area 12 2 Population of Counties or Portions of Counties Vftthin Southeastern Desert Area 13 3 Areas of Hytirographic Units, Southeastern Desert Area Ik k Areas of Counties Within Southeastern Desert Area 15 5 Factors for Reduction of Gross Areas to Net Water Service Areas '+3 6 Land Use in Hydrographic Units of the Southeastern Desert Area in 1958 ^5 7 Land Use in Counties of the Southeastern Desert Area in 1958 ^7 8 Land Use in Service Areas of Major Water Agencies of the Southeastern Desert Area in 1958 '+9 9 Land Use Comparison in Hydrographic Units of the Southeastern Desert Area Between 1950 and 1958 53 10 Disposition During Resurvey Period of Acreage Ptiund JUllow in Summer 1958 56 11 Estimated Mean Seasonal Unit Values of Net Water Use on Urhan and Suburban Lands, Southeastern Desert Area 62 12 Estimated Mean Seasonal Unit Values of Consumptive Use of Water on Irrigated Lands, Southeastern Desert Area 65 13 Estimated Levels of Net Vfeter Use in the Southeastern Desert Area for Conditions of Development 1950 and I958 68 ILLUSTRATIONS Irrigated Agriculture in Coachella Valley Frontispiece ILLUSTRATIONS The Southeastern Desert Area is Characteristi- cally a Region of Barren Mountain Ranges ajid Isolated Hills Surrounding Broad Valleys or Basins 8 Urban Development in Apple Valley, 1959 21 Urban Development and Agriculture in the Vicinity of Lancaster, 1958 2k Land Use Expansion in Palm Springs, 19^ to 1959 29 Imperial Valley near Calexico 33 Agricultxire Bordering the Colorado River in Palo Verde Valley 35 All American Canal at the Coachella Canal Turnout 58 PLATES Plate No. 1 Area of Investigation and Hydrographic Units 2 Ground Water Basins 3 Present Land Use k Change in Land Use, Antelope Valley and Vicinity, 1950 to 1957 5 Change in Land Use, Coachella and Palo Verde Valleys and Vicinities, 195O to 1958 APPENDIXES Appendix Page A Definition of Terms A-1 B Irrigated Agricultural Land Use in Imperial Irrigation District in June, September, and December I958; and March 1959 B-1 vi APPENDIXES Appendix Page C Land Use in Ground Water Basins of the Lahontan Area of Southeastern California, I958 C-1 D Land Use in Groiind Water Basins of the Colorado Desert Area, I958 D-1 vii EDMUND G. BROWN WILLIAM E. WARNE WILLIAM E. WARNE ^cTSlf PEt8:;ii?^ITjE°N''cY P^nT'^'' Director of r. U. Box 3oo Water Resources ^g!^^^^ Socromenio 2. Co B. ABBOn GOLDBERG Chief Deputy Director REGINALD C. PRICE Deputy Director Policy NEELY GARDNER Deputy Director Administration THE RESOURCES AGENCY OF CALIFORNIA ALFRED R. GOLZE =•■-' E"9in..r DEPARTMENT OF WATER RESOURCES 1120 N STREET, SACRAMENTO December 18, 1962 Honorable Edmund G. Brovm, Governor, and Members of the Legislature of the State of California Gentlemen: I have the honor to transmit herewith Department of Water Resources Bulletin No. 101, entitled "Desert Areas of Southeastern California Land and Water Use Survey, 1958." The report has been pre- pared as a part of the department ' s continuing program of studies of the use of the vrater resources of the State to provide the basis for planning trater development, pursuant to Sections 225, 226, and 232 of the California V/ater Code. The report treats those areas of Kern, Los Angeles, San Bernardino, Riverside, San Diego, and Imperial Counties that drain in- ternally into lakes or dry lake beds, and the easterly portions of San Bernardino, Riverside, and Imperial Counties tributary to the Colorado River. It presents data concerning land use and estimates of water use thereon as of 1958, and evaluates the changes in land and water use since the last survey of the area T.^ras made in 1950. This information will be useful to those agencies concerned with making the most effective use of existing water supplies and in development of plans for additional water supplies to meet cuirrent or expected deficiencies. The results of the 1958 survey of leLnd and water use in the desert areas of southeastern California indicate that during the period from 1950 through 1958 the gross irrigated agricultural acreage increased from 61+2,800 acres to 800,900 acres, a groirth of about 158,100 acres, or 25 percent. These increases occurred primarily on lands within the Coachella Valley, Imperial Valley, and Colorado River Hydrographic Units •vrtiich are, for the most part, within service areas provided with water from the Colorado River. The population in the southeastern desert areas increased from 177,000 to 350,300 in i960, or 98 percent. A direct result of the population growth has been an expansion in the gross urban Honorable Edmund G. Brown, Governor, and Members of the Legislature of the State of 'California and suburban area by 50,000 acres, or l82 percent. The estimated mean seasonal level of total net water uses in this area increased from about 3,^29,000 acre-feet in I95O to 3,658,000 acre-feet in I958, an increase of 229,000 acre-feet, or about 7 percent. The increasing need for water in the desert areas of south- eastern California, coupled with already deficient local water supplies in many localities, points up the need for participation by residents of this area in statewide planning and construction of water resources developments . Sincerely yours, ^/(/^ — « C ' Director ACKNOWLEDGMENT Valuable assistance and data used in this investigation and report were contributed by numerous public and private agencies whose cooperation is gratefully acknowledged. In this regard, special mention is made of the assistance and data received from the following: Imperial Irrigation District Riverside County Agricultural Commission University of California Agricultural Extension Service WILLIAM E. STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES EIMUND G, BROWN, Governor WARNE, Administrator, The Resources Agency of California and Director, Department of Water Resources ALFRED R. GOLZE' , Chief Engineer JOHN R. TEERINK, Assistant Chief Engineer SOUTHERN DISTRICT James J. Doody District Engineer Lloyd C. Fowler Chief, Planning Branch This investigation and the preparation of this report was conducted under the direction of Donald H. McKillop .... Chief, Water Supply and Utilization Section and Robert F. Clawson Senior Engineer by Elwood C. Johnson Vfater Resources Engineering Associate assisted by Barry P. Brown Assistant Land and Water Use Analyst Robert D. Etaith Assistant Land and Water Use Analyst Albert F. Knuth Junior Civil Engineer Claude C. Carter, Jr Water Resources Technician I Evangeline Schulten Engineering Aide I Sumi Minatoya Delineator xl CHAPTEB I. INTRODUCTION The widespread belief that desert areas consist only of vast reaches of barren, desolate waste lands, totally devoid of water and continuously subject to extreme heat, is a common misconception. For despite the extremely high summer temperatures and the apparent lack of water, mgn has created an extensive cultural development in the desert areas of southeastern California, changing the character of the land with his works. Particularly in those regions of the desert area where man has developed a stable and dependable water supply, based on native ground water stored in underground reservoirs or water imported from other areas, has the desert been transformed into fertile, green farm land. This report indicates the Inroads that man has made in the desert areas of southeastern California by 1958, and presents information on the rate of development and the increasing needs of this cultural development for water. It is one of a series of bulletins presenting the results of studies made by the Department of Water Resources pursuant to legislative directive, and contains the results of a land and water use survey conducted in the southeastern desert area of California during the summers of 1957 and 1958.' Land use information is gathered to obtain basic data from which present water requirements can be computed. A knowledge of historical and current jiattems of land use not only permits such computations but, of more importance to the overall planning concept, permits an analysis of the direction and magnitude of land use changes taking place from one survey to another. This Information, coupled with computations of changes in water requirements provides the basis upon which future water require- ments are determined, and upon ^rtiich the planning for importation and distribution systems is carried out. The material presented herein is intended for the use of responsible agencies in making the most effec- tive use of existing water supplies and in developing additional supplies to meet current and expected deficiencies. Authorization The California Legislature of 1929 enacted legislation desig- nated Chapter 832, Statutes of 1929, quoted in part as follows: "SECTION 1. Out of any money in the state treasury not otherwise appropriated, the sum of four hundred fifty thoussmd dollars,* or so much thereof as may be necessary, is hereby appropriated to be expended by the state department of public works in accordance with law in conducting work of exploration, investigation and preliminary pleuis in furtherance of a coordi- nated plan for the conservation, development and utilization of the water resources of California including the Santa Ana River and its tributaries, the Mojave river sind its tributaries, and all other water resources of southern California." * Reduced by the Governor to $390,000 Subsequent sessions of the Legislature have appropriated funds for support of the Division of Water Resources and the Department of Water Resources. Portions of these funds have been utilized for con- tinuing investigations of the water resources of southern California and the utilization thereof in accordance with the legislative intent ex- pressed in the foregoing statute and in Sections 225 and 226 of the California Water Code. Section 232 of the Water Code, added by Chapter 6I, Statutes of 1956 (First Extra Session), further directed the Department of Vfeiter Resources to make continuing investigations to develop "information as -2- to water which can be made available for exportation from the watersheds in which it originates without depriving those watersheds of water necessary for beneficial uses therein." This legislation specifically- requested investigation of the following matters: "(a) The boundaries of the respective watersheds of the State and the quantities of water originating therein; (b) The quantities of water reasonably required for ultimate beneficial use in the respective watersheds; (c) The quantities of water, if any, available for export from the respective watersheds; and (d) The areas which can be served by the water available for export from each watershed; (e) The present uses of water within each watershed together with the apparent claim of water right attaching thereto, excluding individual uses of water involving diversions of small quantities which, in the judge- ment of the Director of Water Resoiirces, are insufficient in the aggregate to materially affect the quantitative determin- ations included in the report." Pursuant to the foregoing legislative directives, the Depart- ment of Vfeter Resources began a program of continuing surveys of land and water use in the water-deficient southern California area during 1957' Surveys are made In one of five portions of the whole area each year, so that land and water use are determined at five-year Intervals. Scope of Investigation and Report This report contains the results of a comprehensive survey con- ducted by the Department of Mater Resources to determine the nature and extent of land and water use within the southeastern desert area of southern California. The area of Investigation is shown on Plate 1, "Area of Investigation and Hydrographlc Units . " Present land use was determined from an assimilation of three detailed field surveys. The department conducted a land and water use survey in the Antelope Valley and Mojave River eo-eas during the summer of 1957 for use in the preparation of Bulletin No. 78, "Investigation of -3- Alternative Aqueduct Systems to Serve Southern California," ajid surveyed most of the remaining portion of the investigational area during the summer of 1958 • Supplemental surveys were also conducted at three month intervals after the main summer survey in several areas subject to multi- ple cropping to determine crop patterns and water requirements. Imperial Irrigation District conducts quarterly inventories of crops grown within its houndarles, and the March 1959 survey of agricultural land use by that district was integrated into the main body of data for this report. In addition to showing present land use, this report presents a narration of historical land use development and changes, and an estimate of the present levels of water use. Data obtained frcan the land use sur- vey conducted In 1950 and presented in Bulletin No. 2, "Water Utilization and Requirements of Callfomia, " were utilized as the basis for comparison between the 1950 axid 1958 land use i>atterTis and water requirements . Infor- mation on local water supplies and impoi-tations of water were obtained f^om operating agencies In the area of investigation, or developed from material in the department's files. Terms used in this report, which require clarification, are defined at the point where they first occiir in the tejct, and are supple- mented by a list of definitions, presented in Appendix A. Other appendixes presented with this report aj-e Appendix B, Irrigated Agricultural Land Use in Imperial Irrigation District in June, September, and December 1958, and March 1959; Appendix C, Land Use in Ground Water Basins of the Lahontan Area of Southeastern California, 1958; and Appendix D, Land Use in Ground Water Basins of the Colorado Desert Area, I958. -k- Related Investigations smd Reports The California Legislature of I9U7, ty Chapter 15^+1, Statutes of 19'*^7> directed the Department of Water Resources and its predecessor agencies to conduct a comprehensive investigation of the vra,ter resources of the entire State of California. The Investigation had as its purpose the preparation of the California Water Plsji. Results of the investiga- tion are contained in three publications: CeLllfornia Water Resources Boeird Bulletin No. 1, "Water Resources of California," 195I; California >fater Resources Board Bulletin No. 2, "Water Utilization and. Requirements of California," June 1955; and California Department of Water Resources Bulletin No. 3, "The California Water Plan," May 1957. The Investigations for Bulletin No. 2 included a survey of land use in 1950 and a determina- tion of water utilization in the southeastern desert area for conditions of 1950. The following reports also contain information pertinent to land and water use within the southeastern desert area: Blaney, Harry F. and Ewing, Paul A. "Utilization of the Waters of Mojave River, California." United States Department of Agriculture. August 1935. Brown, John S. "The Salton Sea Region, California." United States Depart- ment of the Interior, Geological Survey, Vfeter Supply Paper h^J. 1923. California Department of Engineering. "Report on the Utilization of Mojave River for Irrigation in Victor Valley, California." Bulletin No. 5. 1918. Califomla Department of Public Works, Division of Water Resources. "Mojave River Investigation." Bulletin No. 1+7. 193^. California Department of Public Works, Division of Water Resources. "Ground Vfater Occurrence and Quality, Colorado River Basin Region." Water Quality Investigations Report No. h. May 195'*- -5- Hall, William Hammond, State Engineer, "irrigation in Southern California." 1888, Huberty, M. R., Pillsbury, A. F., and Sokoloff, V. P. "Hydrologic Studies in Coachella Valley, California." University of California. June 19hQ. Mendenhall, Walter C. "Ground Waters of the Indio Region, California." United States Department of the Interior, Geological Survey, Water Supply Paper 225. 1909- Thompson, David G. "The Mojave Desert Region, California." United States Department of the Interior, Geological Survey, Water Supply Paper 579- 1929. United States Department of the Interior, Bureau of Reclamation. "Report on Water Supply of the Lower Colorado River Basin." November 1952. I r I- K ■ CHAPTER II. AREA OF INVESTIGATION The area under investigation, broadly designated the South- eastern Desert Area of California, consists of those lands generally easterly of the drainage divide of the Sierra Nevada, Tehachapi, San Gabriel, San Bernardino, San Jacinto, and Peninsular Mountain ranges. As shown on Plate 1, the area is bounded on the north by the Inyo-Kern, San Bernardino County line, on the east by the Nevada State line and the Colorado River, and on the south by the International Boundary between the United States and Mexico. This vast region, some 220 miles long and varying In width from about 110 to 230 miles, encompasses a total of approximately 3!+, 000 squaxe miles. The area includes those portions of Los Angeles, San Bernardino, Riverside, San Diego, and Imperial Counties that drain inter- nally into lakes or dry lake beds and that portion of Kern County southeast of the Tehachapi Mountains. The extreme easterly areas of San Bernardino, Riverside, and Imperial Counties that are tributary to the Colorado River are also Included within the investigational boundaries. The locations of the major ground water basins within this area are shown on Plate 2, "Ground Water Basins." Portions of some minor drainage basins lie in Nevada, however, this investigation was limited to the area within California's bovmdaries. Climatic Conditions The climate of the desert area varies widely with topography and latitude. During the winter, temperatures below 32* F are common in the high mountain ranges forming the westerly boundary of the area and frequently occur over much of the higher desert expanses to the north -9- and northwest. In contrast, the winters are typically short and mild throughout the lower southerly section of the area. The entire area is char8u:terized ty hot summers with low humidity and scant rainfall, and there is a marked contrast between day and night temperatures, both seasonally and diurnally. Precipitation, althoxigh extremely light and irregular over ne£u*ly the entire area, is the major source of replenishment to the ground water basins, except those ground water reservoirs in the south- I eastern portion which are replenished by deep percolation of applied I Colorado River water. Snowf a1 1 is common in the high mountains during the winters, and also occtits occasionally on the high desert eireas to the north and northwest. Mean seasonal precipitation for the 50- year period from I897-98 to 19k6-h7 at Big Pines Park in the San Gabriel Mountains is 25.6 inches, and at Raywood Flats in the San Bernardino ' Movmtains, 37 .8 inches. Typical mean seasonal depths of precipitation in desert valleys are k.9 inches at Mojave, 7-0 inches at Lancaster, k.l inches at Barstow, 5.5 inches at Victorville, 3.6 inches at Indio, 3.2 inches at El Centro, 4.0 inches at Blythe, and 4.8 inches at Needles. | Generally, precipitation over the entire area occurs from November j through April, although local thunder storms occurring at random intervals may, during some years, contribute much more than the equivalent of average seasonal precipitation to local areas in very short periods. At several stations within the area only a trace of precipitation has been recorded for entire seasons. Cultural Developnent The southeastern desert area of California is character- Isticeilly a region of barren mountain ranges and isolated hills surrounding -10- troad valleys or basins. Developnent is for the most part confined to relatively flat valley areas where water supplies are available. A large portion of this area is entirely dependent on ground water for water supplies. Irrigated eigriculture is still the leading economic activity throughout most of the desert area. The largest irrigated acreages are found in Coachella, Imperial, Palo Verde and Yuma Valleys and are made possible by diversions from the Colorado River. Large acreages are also irrigated in Antelope and Mojave River Valleys by the use of ground water. In general, the total irrigated acreage has steadily increased through the years, although decreases in acreage have resulted from declining ground water levels and consequent increases in the costs of pumping water in Antelope Valley and some smaller areas. Develoiment of industries which are dependent on agricultural production have closely followed the agricultural growth. In addition, the establishment of several major military installations, including flight and missile testing facilities and related production plants, has resulted in large-scale industrial expansion, particularly in Antelope Valley. The desert area has been a center of mining interest for nearly 100 years. A large number of minerals has been foiind throughout the desert, and many of these are mined and marketed. Water requirements for these mining operations are small in relation to irrigation requirements and have usually been met by jjumping from local supplies of ground water or by diversions from springs. Population in the desert area historically has been an adjunct to BgritiiltTiral activity and to mining in a lesser degree. The cities and urban communities are characteristically widely scattered and rela- tively small. Notable exceptions to this, within the last two decades. -11- are the increases in population traceable to the estatllshment of major military and related aircraft industrial installations in and around Lancaster and Palmdale, and the recreational developnient surrounding the cities of Palm Springs, Desert Hot Springs, and Twentynine Palms. Table 1 shows population trends in ten representative cities from 19^+0 to 19^0, as well as two unincorporated urban centers. The unincorporated \irban centers do not have fixed boundaries so the population figures throiigh the years are not entirely comparable. Table 2 shows increases in population for the areas of the portion of each county contained within the southeastern desert area for the years 19^0, 1950, and 1960. TABLE 1 POPULATION OF PRINCIPAL URBAN CENTERS SOUTHEASTERN DESERT AREA City Years Lancaster* El Centre Palm Springs Brawley Bar stow Banning Indio Victorvllle Calexico Blythe Needles Mojave* 19'tO : 1950 I960 2,100 3,600 26,000 10,000 12,600 16,800 3,U00 7,700 13,500 11,700 11,900 12,700 2,100 6,100 11,600 3,900 7,000 10,200 2,300 5,300 9,700 2,000 3,200 8,200 5,U00 6,400 8,000 2,1*00 1+,100 6,000 3,600 1^,100 i+,6oo 1,200 2,100 1,800 ♦Unincorporated areas. -12- TABLE 2 POPULATION OF COUNTIES OR PORTIONS OF COUNTIES WITHIN SOUTHEASTERN DESERT AREA County Years 1940 : 1950 : i960 1,500 11,500 36,700 7,700 16,100 68,200 18,200 39,^^0 89,500 23,100 45,400 81,800 59,700 63,000 72,100 600 1,600 2,000 Kern Los Angeles San Bernardino Riverside Imperial San Diego Totals 110,800 177,000 350,300 Since World War II there has heen a general awakening of Inter- est in the desert as an answer to the recreational needs of the growing Ceilifornia poiwlation. This interest has stimulated a remarkable rate of population growth in the recreational areas and a new pattern of land use is developing. Commercial and industrial enterprises are also developing to support the growing population centers. Hydrographic Units On the hasis of cultural developnent, surface drainage, and geological considerations related to the occurrence of grotind water, the desert area has been broadly subdivided into nine major hydrographic units. These units and their numericed. designations are: Death Valley (6-10), Mojave River (6-II), Antelope VeLLLey (6-12), Twentynine Palms (7-1), Coachella Valley (7-2), Salton Sea (7-3), Itaperial Valley (7-^), Colorado River (7-5) and Lanfalr Valley (7-6). The boundaries of these -13- units, shown on Plate 1, correspond to those into which the southern portion of the Lahontaxi area and the entire Colorado River area were subdivided for use in Bulletin No. 2, with the exception that the Death Valley Unit has been arbitrarily split at the Inyo-Kern, San Bernardino County line for the purposes of this study. The gross areas of these units are presented in Table 3. The eireas of that portion of each county included within the southeastern desert area are given in Table h. TABLE 3 AREAS OF HYDROGRAPHIC UNITS SOUTHEASTERN DESERT AREA Hydrographic unit : Acres Death Valley (6-10) 4,422,000 Mojave River (6-11) 3,140,000 Antelope Valley (6-12) 1,546,000 Twentynine Palms (7- 1) 3,867,000 Coachella Valley (7- 2) 1,355,000 Salton Sea (7- 3) 1,898,000 Imperial Valley (7- h) 1,007,000 Colorado River (7- 5) 2,254,000 TAnfair Valley (7- 6) L 2,035,000 APPROXIMATE TOTA 21,524,000 -14- TABLE ^4^ AREAS OF COUNTIES WITHIN SOUTHEASTERN DESERT AREA County : Acres Kern 1,624,000 Los Angeles 723,000 San Bernardino 12,275,000 Riverside 3, 510, 000 Imperial 2, 587, 000 San Diego 805,000 APPROXIMATE TOTAL 21, 52i+,000 A brief description of the physiography, cultural developnent, and vater supply and use in each of the hydrographic units is given in the remaining portion of this chapter. Death Valley Unit (6-10) The boundaries of the Death Veilley Unit correspond to those of a similar hydrographic unit previously delineated in Bulletin No. 2, except that for this investigation only that portion of the earlier unit located south of the Inyo-Kem, San Bernardino County line has been included in the survey. The boundaries of the unit, shown on Plate 1, are the Nevada- California State line on the northeast, the drainage divide of the Mojave River and Antelope Valley on the south, the drainage divide of the Tehachapi and Sierra Nevada Mountains on the west, and the Inyo-Kern, San Bernardino County line on the north. The area encompassed by this unit is about 6,900 square miles. There are no perennial streams in the area of this hydrographic unit. The Amargosa River, which is the largest intermittent stream ■15- system in the area, originates in southwestern Nevada. Its course trav- erses eastern Inyo County, loops through northeastern San Bernardino County, and re-enters Inyo County, terminating in Death Valley. Even through the Amargosa River drains a large area, surface flow in its lower reaches is rare. Ground water has been extracted by wells located along the river for limited domestic and irrigation use. However, available information indicates that the high salt content of the ground water in the lower reaches of this stream valley generally precludes its use for domestic or agricultured. purposes. Many attempts have been made by homesteaders and others to develop and irrigate parts of other valleys in this area of the desert beginning shortly after the turn of the century. These attempts have for the most part ended in failure primarily because of insufficient supplies of good quality ground water. However, in the western section of the Death Valley Unit, irrigated acreages exist today in portions of Indian Wells Valley near the town of Ridgecrest, in Fremont Valley near Cantil, and in Harper Valley located a short distance northwest of Barstow. In 1957> irrigated agricultural acreages in these valleys were about 600, 5,600, and 2,200 acres, respectively. Available information indicates that larger acreages have been irrigated in the past, however, declining ground water levels, particularly in Harper Valley, have resulted in some decrease in irrigated acreage. The principal crops are alfalfa, field crops, and pasture. The raising of livestock is another agricultTiral activity in this area, and cattle are grazed over much of the lands, particularly in the eastern and western sections. .16- Mining has been rather extensively developed in this area with the extraction of saline deposits from Searles Lake, an almost contin- uous operation since 1873- Several talc mines are located in north- eastern San Bernardino County, and over the years many other mineral and salt deposits have been intermittently mined, particularly in the eastern section of the Death Valley Unit. Industrial development has been somewhat limited although there are some light industrial facilities on the military reservations in the area, and a fe^ mineral processing plants in operation, usually near the mineral deposits. Mojave River Unit (6-11) The Mojave River Unit is located in San Bernardino County in the north central section of the area of investigation and contains an area of about 11,900 square miles j the unit boundaries are shown on Plate 1. The principal sources of water supply for the area within this unit are groimd water and surface water from the Mojave River whose headwaters drain almost the entire northern slopes of the San Bernardino Mo\intains. The two larger tributaries of this river are Deep Creek ajid West Fork of the Mojave River, which are generally perennial in their upper reaches in the mountains and which join near the base of the mountains at an elevation of about 3,000 feet. Downstreajn from the con- fluence of these tributaries, the river traverses the Mojave Desert in a northerly direction for a distance of about 30 miles to Helendale. Its course is then northeastward some 20 miles to Barstow, where it turns eastward kO miles to Soda Lake in the vicinity of Baker. -17- Surface flow in the Mojave River isnally percolates rapidly into its pervious channel downstream from the mojntains, except during high flow periods. However, even during dry periods rising water (outflow from the upstream ground water basins) appears as surface flow in the river channel at Victorville and at Afton. No significant tributaries contribute surface water to the river below the mountains, although some underflow is received from the mountains as far west as Sheep Creek. The Mojave River Valley has been divided on the basis of physiographic and geologic features into three subbasins designated the Upper, Middle, and Lower Mojave River Valleys, and cultural developnent in this unit has been primarily centered in these valleys. The Upper Valley is a part of a broad piedmont plain that abuts the northern front of the San Gabriel and San Bernardino Mountains for a distance of about 100 miles. This piedmont plain, which includes Apple Valley on the east of the river and the Hesperia area on the west, slopes away to the north toward Victorville where it is bounded by the Middle Mojave River Valley. The ground surface elevation of this plain varies from about 4,000 feet at the base of the mountains to 2,500 feet at Helendale. The boundary between the Upper and Middle Mojave River Valleys is the Helendale fault which crosses the valley at Helendale. Bedrock bairriers across the valley in the vicinity of Victorville bring ground water to the surface as perennial rising water. The Middle Mojave River Valley is an irregularly shaped area extending from Helendale to Barstow. Its average elevation is about 2,500 feet. A natural geological barrier at Barstow separates the Middle and Lower Mojave River Valleys. Surface flow has occurred here in recent years only during short periods of high river flow. The Lower -18- Mojave River Valley is also irregularly shaped and trends toward the northeast. At its lower eastern end, the river discharges through Caves Canyon where perennial surface flow, rising ground water, is present in the vicinity of Afton. Beyond this cajiyon the Mojave River discheirges into the desert expanses of the Soda Lake Basin south of Baker. Infre- quent large floods in the upper reaches of the Mojave River watershed have produced considerable quantities of r\moff into Soda Lake. Significant cultural development in the Mojave River Valley began at an earlier date than in most other sections of the desert area. The Mojave River exhibits an unconmon hydrologic chairacteristic in this area, usually flowing as subsurface water, but appearing as rising surface waters at intervals along its desert reaches. It is believed that the availability of these rising waters, in an otherwise arid envlromnent, was the primary factor in this early development. Immigrants came to Southern California in increasing numbers beginning in the early l830's from New Mexico and the east over the Spanish Trail; they struck the Mojave River at Soda Lake and followed it to the present vicinity of Helendale, then diverged to Cajon Pass and down on to the coastal plain. The first settlements were the stations on the trail located where lands were moist and the flow of the river was sufficient for the growing of hay to feed cattle and supply the freighters. It is believed that a few small ditches were in use for irrigation prior to 187O, and more permanent conduits were constructed from 1873 to 1880. Other choice locations upstream in the vicinity of Victorville and neeir the San Bernardino Mountains were also settled early . -19- Groiind water developnent began prior to 19OO by use of hand- dug pits at points along the river where water was readily obtainable near the sTirface. Improvements in drilling techniques and pumping equipnent after I900 made possible more extensive ground water developnent . It has been reported that by 1915, a total of about 10,000 acres was being Irrigated in the Mojave River Valley, 3,000 acres of this total by surface diversions and 7,000 acres by wells. About 120 wells were operating at this time, 90 of these were pumped and 30 were flowing. The flowing wells were located just above Victorville. The principal crops were apples, pears, and alfalfa. By 1929, this acreage had dropped to about 6,000 acres, planted mainly in alfalfa. The number of operating wells had increased to 257, of which 240 were pumped and 17 were flowing. In 1935, 6,000 acres were irrigated with only 29O-3OO acres of the total served surface water by ditches. The number of operating wells had decreased to approximately 200. The principal crop produced was still alfalfa, although dairying emd poultry production were important agricviltural activities. The 15-year period from 1935 to 1950 provided economic stimulus for more than a two-fold increase in total irrigated acreage which in 1950 amounted to 13,600 acres. Since 1950, the irrigated acreage declined slightly, dropping to 13,000 acres In 1958. Ground water levels in the Mojave River Veilley have generally remained fairly stable, which is a marked contrast to most other developed ground water areas in southern California. Historical data indicate that ground water level elevations in the Upi)er Mojave River Valley have decreased an average of about 15 to 20 feet during the period of record, because of the increased urban and agricultural development in the -20- Victorville, Hesperia, and Apple Valley areas. Only minor lowering of ground water levels has occ\irred in Middle and Lower Mojave River Valleys. Mining is the major industrial activity in Mojave River Valley, and various minerals of economic significance are found in the desert, particularly east of Bar stow. Much of the activity connected with mining is sporadic, varying with fluctuating market conditions, but other indus- trial developnents, such as the large cement manufacturing plants near Victorville and the military installations near Barstow, have been more stable and have stimulated urban development in and around these cities. Antelope Valley Unit (6-12) The Antelope Valley Unit is a major drainage basin in the northwestern portion of the area of investigation. This unit encom- passes about 2, UOO square miles, including those portions of Kern, Los Angeles, and San Bernardino Coimties that drain to Rosamond, Rogers, and Mirage Lakes. As shown on Plate 1, this triangularly- shaped unit has its northern apex near Randsburg in Kern County, and an eastern boundary that roughly parallels the Kern- San Bernardino and Los Angeles- San Bernardino County lines before joining the San Gabriel Mountains on the south. The unit ' s southern boundary trends to the northwest generally along the drainage divide of the San Gabriel Mountains to the Tehachapi Mountains on the west; here, the boundary t\irns northeast along the drainage divide of the Tehachapi s, returning to the northern apex. The Antelope Valley receives runoff from the southeasterly slopes of the Tehachapi Mountains and the northeasterly slopes of the San Gabriel Mountains. Principal streams draining into the valley axe Big Rock Creek and Little Rock Creek, both of which originate in the San Gabriel Mountains. Although these creeks and some other smaller -22- streams are perennial in their upper reaches, they are all intermittent in the valley. Agricultural development in the Antelope Valley Unit has de- pended almost entirely on the success of obtaining adequate water supplies. In the early period of developnent prior to 1900, irrigated agricultural developnent was limited almost entirely to the southwestern fringe of the valley along the base of the San Gabriel Mountains where surface water supplies were utilized, although some dry- farmed grain was produced in the central and western peirt of the valley. It has been estimated that by 1895, about 10,000 acres along the base of the San Gabriel Mountains were irrigated through diversion of surface flow, producing crops of various deciduous fruits, nuts, and alfalfa. Because of the insufficient water supply this acreage was reduced within a short time and stabilized at about 2,000 to 3>000 acres, devoted mainly to deciduous fruits and alfalfa. This acreage has been maintained up to the present time by using surface diversions. Ground water developnent in the valley prior to I9OO consisted of a few shallow domestic wells. With the advent of the deep well turbine pump around I9OO, about ij-O wells were constructed in the vicinity of Lancaster, mainly for irrigation of alfalfa. However, it was not until the introduction of electric power to Antelope Valley in 191'+, that relatively large scale ground water developnent took place. This accel- erated period of irrigated agricultural developnent continued until about 1929, at which time about 85O wells were being used for irrigation of about 25,000 acres planted mainly in alfalfa. During this period ground water levels in the valley began dropping appreciably, signalling the onset of the serious overdraft condition which exists today. ■23- During the decade of the 19to's, economic conditions stimulated additional large scale increases in agricultTiral developnent in the Antelope Valley Unit. By 1950, more than 1,000 wells were being operated for irrigation of a total of 70,000 acres. This trend has heen reversed, however, and during the last ten years Irrigated acreage in the valley has decreased somewhat, mainly because of Increased pumping costs caused by severely declining ground water levels. In contrast to this decline in irrigated acreage, poultry production has become Increasingly imjxDrtant to the area's agricultural economy, and now in terms of value of production, it is one of the most important agricultural enterprises. Industrial activity in Antelope Valley prior to 1950 was minor in extent and was tied closely to agricxiltural develojment. During the past decade, however, there has been a marked expansion caused by the Introduction of major military and related aircraft Industrial instal- lations located near Lancaster and Palmdale. Other major industrial developments in Anteloi)e Valley Include mining and mineral processing plants. Twentynine Palms Unit (7-1) The Twentynine Palms Unit encompasses a large desert region located within south central Sem Bernardino County and eastern Riverside County. As shown on Plate 1, the area of this hydrographlc unit is bovmded on the east by the Colorado River drainage divide; on the south- west by the San Bernardino, Little San Bernardino, and Chocolate Moimtains; on the west and north by Mojave River Valley; and on the northeast by a line passing thro\:igh the Old Woman Mountains in a north- westerly direction. This unit encompasses an area of about 6,000 square miles. -25- Although this area contains several internally drained basins, all streams in this hydrographic unit are ephemeral and ground water has supplied most of the needs of the culture which has developed here. How- ever, supplies of good quality ground water in sufficient quantities to sustain domestic and agricultural developnent have been limited, and such development has occurred primarily in the Lucerne Valley and Twenty- nine Palms areas. Early agricultural development, which commenced prior to 1900, was confined to stock grazing in the vicinity of Lucerne Valley and in Johnson Valley around Old Woman Springs. This activity has continued to the present, and in addition, about 2,000 acres planted mainly to alfalfa and pasture have been developed in Lucerne Valley. This is practically the only irrigated acreage located in the entire unit. The oasis at Twentynine Palms has been a well known desert watering place during the period of available historical records. Until recently the population in the area surrounding Twentynine Palms remained quite small but short-lived increases occurred as a result of mining activity in the adjacent desert areas. In recent years, the area's equitable winter climate has been a prime factor in the large scale development of a week-end type resort area, and has also led to estab- lishment of many permanent residences. In addition, the installation of a U. S. Marine Corp Training Center nearby has also encouraged an increase in the number of permanent residents in this area. Industrial developnent in this region of the desert is restricted almost entirely to mining. Two large iron ore deposits, one located at the northeast end of the Eagle Mountains and the other near Twentynine Palms, are operated to supply ore to the Kaiser Steel Mill at -26- Fontana. CaJ-Cium chloride is mined from Bristol Dry Lake. Many other minersils and chemicals are mined throughout the region, although these operations are characteristically sporadic and vary with market conditions. Coachella Valley Unit (7-2) The Coachella Valley Unit lies in the west central part of the southeastern desert area primarily within south central Riverside County. This imit is bounded on the north by the San Bernardino Moxintains, on the northeast by the Little San Bernardino Mountains, and on the east by the Orocopia Mountains. The southern boundary is arbitrarily drawn along the northwest shore of the Salton Sea, and is joined on the southwest by the San Jacinto and Ssmta Rosa Mountains. These boundai-ies are shown on Plate 1. The Coachella Valley Unit has an area of about 2,100 square miles, and varies in elevation from 235 feet below sea level at Salton Sea to 11, k&^ feet above sea level at Mount San Gorgonio . The principal stream is the Whitewater River, which originates on the southeast slopes of Mt. San Gorgonio in the San Bernardino Mountains, discharges into the north end of the valley, and continues in a southeasterly direction to the Salton Sea. The channel of this river serves as the principal i>ath for natural surface drainage from the valley to the Salton Sea, and is used to drain irrigation return water in the lower valley where the channel has been improved. The principal tributaries of the Whitewater River are San Gorgonio River, and the Snow, Chino, Tahqiiitz, Palm Canyon, Deep Canyon, Mission, Big Morongo, and Little Morongo Creeks. Some of these larger tributEiries are perennial streams in the mountains, but quickly percolate upon reaching the highly pervious alluvium in the valley. Natural -27- surface runoff from these streams, therefore, reaches the Salton Sea only during infrequent floods of large magnitude. The first develojment of ground water in this iinit occurred in 189^ when a well was drilled at Mecca, providing a supply of good quality artesian water. It was not until I9OO, however, that improved methods of well construction and pumping equipment made available large quantities of ground water. By 1907> there were about 400 wells, many of them flowing, used for irrigation and domestic purposes in the region between Indio and the Salton Sea. With water available for irrigation, land in the Coachella Valley Unit is well suited to the production of specialty crops because of the mild winter temperatures and sunny days which prevail. The principal crops have been truck crops, dates, citrus, and table grapes. By 1936-37^ a total of 15,500 acres was being irrigated in this area. The economic stimulus which occurred during the decade of the 19^ 's resulted in a two- fold increase in irrigated acreage, and by 1950 there were about 30,000 acres under irrigation. The first deliveries of Colorado River water, imported to the valley through the Coachella Branch of the All American Canal in April 19'+9> gave still another impetus to the growth of irrigated agriculture in this unit and by 1958, this developnent totaled about 68,000 acres. Although there has been no major industrial developnent in this area, much urban developnent can be attributed to the vacation resorts which have proved particuleirly adapted to Coachella Valley, centering in the Palm Springs and Indio areas; and in addition, senior type retirement homes are becoming a major attraction within the va3J.ey. -28- ""^ ■ ■■ : ■ > " : t^TSW XnUMCfTMUV Land Use Expansion in Palm Springs, 1940 to 1959 Courtesy Spence Air Phoios Courtejy Spenc« Air Photoi Salton Sea Unit (7-3) The Salton Sea Unit is located in the southwestern and south central portion of the area of Investigation, and encQmi)asses the Salton Sea and parts of Riverside, Imperial, ajid San Diego Counties within its boundaries. As shown on Plate 1, this hydrographic unit is bounded on the north by the Santa Rosa and Orocopia Mountains, and on the east by a line passing southeasterly through the Chocolate Mountains. The southern boundary proceeds in an irregular line west from the Chocolate Moimtains, turns north to the Salton Sea, then from the western side of the Salton Sea south again to the United States-Mexico International Border. The western boundary proceeds northward from the border along the crest of the Laguna and Cuyamaca Movintains, passes near Julian, and joins the northern boundary at the west end of the Santa Rosa Mountains. The area of this unit is about 3*000 square miles. The upper watershed areas in this unit northwest of the Salton Sea are drained by Coyote and San Felipe Creeks; those to the southwest are drained by Vallecito and Carrizo Creeks, and those to the east of Salton Sea by Salton Creek. These creeks, and all other streams within the boundaries of this unit are ephemeral. Although lack of adequate ground water supplies of good quality has seriously limited agricultural and other development in most of the Salton Sea Unit, l4 ground water basins have been delineated within its boundaries. Ground water pumped from some of these basins has supported intensive development; one notably, about '+,500 acres of irrigated agriculture in Borrego Valley, planted mainly in table grapes and alfalfa. -30- Industrial development has been negligible in this unit, but some urban developnent has occurred along the shores of the Salton Sea, based primarily on vacation resorts. However, even this developnent was limited by an inadequate supply of local water suitable for domestic purposes. In I96I ground water from the Coachella Valley Unit was Imported to portions of this unit. Imperial Valley Unit (7-'^) The Imperial Valley Unit is located in the south central portion of the area of investigation, encompassing a portion of Imperial County which lies south of the Salton Sea. This hydrographic unit is bounded on the north by the Salton Sea and on the east by the Sand Hills. As shown on Plate 1, its southern boundary is the United States-Mexico International Border. To the west, it is bounded by the Coyote Mountains and the Fish Creek Mountains. This unit contains about 1,600 square miles which lie primarily below sea level. The New and Alamo Rivers, which originate in the Mexicali Valley in Mexico and flow northward through the Imperial Valley to the Salton Sea, are the two major streams in this unit. Most of the flow of these rivers crossing the International Border is drainage water from irrigated portions of Mexicali Valley, although part of the flow of the New River originates as domestic and industrial wastes from Mexicali and Calexico. In addition, large volumes of seepage and drainage water from irrigated areas in Imperial Valley empty into the channels of these two rivers in their course towards the Salton Sea. Ground water has never been developed to any appreciable extent in this unit, primarily because of its poor quality. The more -31- productive etgricultiiral lemds in the central portion of the valley are composed of sandy silts and clays of relatively low permeability; these sediments extend to considerable depths, and do not yield ground water in large quantities. The use of Colorado River water in the Imperial Veilley for irrigation was first conceived around i860. However, delivery of water to the valley did not commence iintil June 1901, and the first major agricultural development occurred between 1909 and I916. Imported water was delivered to the valley through the Mexican Canal System until 19^2, when the All American Canal was placed in operation and began to transport water from Imperial Dam on the Colorado River to this area. The Imperial Irrigation District, which is the water service agency for this area, contains about 1,000,000 acres within its boundaries, including all of the irrigated area in the valley. By 19't3, some J*00,000 acres were under irrigation within this unit with the principeil crops being alfalfa, field crops, and truck crops. The irrigated acreage had increased to about 1)66,000 by 1958> and the principal crops remained unchanged, although larger acreages were being planted in small grains than in the past. Major Industrial develojBient has not occurred in this ujiit, but the urban developnent has been somewhat more extensive in this area than in other units. The cities of Brawley, El Centro, and Calexico are railroad and trading centers, and development has centered prtmaxily around the packing and shipping of agricultural produce on a year-round basis. -32- Colorado River Unit (7-^) The Colorado River Unit is located In the extreme easterly portion of the area of investigation, encompassing portions of San Bernardino, Riverside, and Imperial Counties. As shown on Plate 1, the area of this hydrographic unit is bounded on the north and east hy the California-Nevada and California-Arizona state lines, respectively, and on the south by the International Border between the United States and Mexico. Its western boundary is formed by the drainage divide for streams in California that are directly tributary to the Colorado River and those which flow into interior sinks. The area of this unit is about 3*500 square miles. All of the streams tributary to the Colorado River from California are ephemeral, flowing only after heavy rain storms, and are of minor significance to the area's water supply. The Colorado River, however, has long been an important source of water in this unit. Those sections of this unit adjacent to the Colorado River having established rights to the use of its waters are presently highly developed, primarily in irrigated agriculture. The major irrigated agricultural developnents in this unit are located in the Palo Verde Valley near Blythe, and the portion of the Yuma Project of the United States Bureau of Reclamation located in the extreme southeastern corner of California. Agricultural developnent of Isinds in the Palo Verde Valley date from l877 when the first filing for water rights for the amount necessary to irrigate i+O, 000 acres was made. Al- though little development occurred until 190i^, the completion of the first railroad connection to the valley in 1915 stimulated its growth; by 1950, the total irrigated acreage included about 55>000 acres, planted in alfalfa, truck crops, grain, and pasture. In 1958, the irrigated acreage was about 72,000, 1 Water from the Colorado River is obtained by a diversion at the recently completed Palo Verde Dam smd distributed by the Palo Verde Irrigation District. This district encompassed about 120,500 acres with- in its boundaries in 1959- Limited amounts of additional water for irrigation are obtained from wells, primarily on the mesa lands surrounding the Palo Verde Valley. The Yuma Project, authorized in I90U, is a United States Bureau of Reclamation irrigation development and includes portions of California and Arizona adjacent to the Colorado River. The California portion of the project, designated the Reservation Division, contains about 15,000 acres. The Indian Unit contains about 8,000 acres, while the remaining 7,000 acres are allotted to non- Indian operators and comprise the Bard Irrigation District. Industrial develojment has been limited in the Colorado River Unit, but the Colorado River area has become very popular as a recreational axea in recent years. The mild winters with sunny days, and the excellent boating and fishing have drawn an increasingly large number of recreation- ists to this area. Lanfair Valley Unit (7-6) The northeast boundary of the Lanfair Valley Unit is the state line between Nevada and California. The east boundary is on the drainage divide of the Colorado River. The southwest boundary is a northwesterly trending line passing through the Old Woman Mountains, which separates this unit from the Twentynine Palms Unit, and its northwest boundary is .36- along the Providence and New York Mountains. These boundaries are shown on Plate 1. The Lanfair Valley Unit encompasses an area of about 3,200 square miles. The northeast section forms a large surface drainage area which is exceeded in size only by the Mojave River Valley in the area of investi- gation. The divide begins at the crest of the Providence and New York Mountains and contains the large land areas of Lanfair and Fenner Valleys. The drainage terminates at Bristol Dry Lake at the lower end. The ground surface elevation of Lanfair Vsilley is about if, 000 feet, which is greater than other desert basins within the investigational area. Even with this large surface drainage there are no perennial streams. The southern portion of the Lanfair Valley Unit contains several basins or valleys most of which Eire isolated with little or no development. In the years immediately following the turn of the centxiry, many settlers took up homesteads in Lanfair Valley and also, to a limited extent, in Fenner Valley. Many attempts were made to raise crops by dry farming. Although Lanfair Valley enjoys somewhat more rainfall than is common in the lower desert areas, these ventures failed for lack of sufficient water. A few wells were drilled but pumping lifts were too great and yields too small to sustain irrigated agriculture. By 1920, attempts to farm the land ceased and the only remaining agriciJ.tural activity was cattle grazing, which has continued to the present time. Mining in the Lanfair Valley Unit is essentially the only industrial activity. Many minerals and chemical deposits 8u:e known to exist althoi:gh, as in most of the other desert areas, these operations are intermittent depending on market conditions. No mines of appreciable size operate on a continuous basis in the area. -37- CHAPTER III. LAND USE The nature, location and area! extent of current land use within the study area was determined by a coirrpilation of data from two surveys conducted by the Department of Water Resources during the summers of 1957 and 1958 and from a survey of Imperial Valley conducted by the Imperial Irrigation District during March of 1959- In addition, supplemental surveys were conducted by the department in Coachella, Borrego and Palo Verde Valleys during 1958-59 at intervEils of approximately three months. These supplemental surveys were carried out for the purpose of evaluating agri- cultural practices in areas where climatic conditions ordinarily permit a year-round growing season. Supplemental surveys were also conducted by the Inperial Irrigation District and appear in this report as i^pendix B. A discussion of survey methods and procedures, and the results of these siirveys are summarized in this chapter. Methods and Procedures In order to relate present land use data to historical data, this investigation en^loyed survey procedures similar to those used in the 1950 survey, which is described in Bulletin No. 2. Departmental sur- vey teams delineated acreages of the various land use classes in the field on either vertical aerial photographs, or on United States Geological Sur- vey quadrangle maps where photographic coverage was not available. In the office, field delineations were transferred by projection to acetate overlays of United States Geological Survey quadrangle maps of 1:2^000 sc£Lle. These maps served as area control maps, ensuring the accuracy of the succeeding processes while the acetate overlays served as masters for -39- reproducing land use delineations on vellum prints. The individual areas of land use classes were cut from the vellum prints and weighed, and by machine confuting processes these weights were converted into total acre- ages of individual land use classes. Because of the control developed as ' the result of the use of quadxaiigles, the overall results can be considered accurate to within about plus or minus three percent. However, the results for individual areas should not be considered to have an accuracy of more than plus or minus five percent. | As discussed earlier, all agricultural land use development | t within the Iii5)erial Irrigation District was surveyed and recorded by personnel of that district. The results of their survey were adjusted to conform with the department's land use categories and incorporated into the summary tables in this chapter. ; For purposes of a critical hydrologic analysis it would be desirable to determine and con5>ile the types of land use, either undeveloped or developed, for the entire area of the hydrographic unit, permitting a comprehensive analysis and evaluation of the various levels of water use for the entire area. However, such a complete compilation is time con- signing and expensive, and it is the usual practice to curtail the activities in those areas which are not underlain by water-bearing material only to mapping those classes of land use requiring applied water. However, even this was considered inappropriate for the present study since cultural development in the southeastern desert area has been of a limited localized nature. Therefore, detailed land use surveys, where all classes of land use are delineated, were conducted only in those areas of intensive cultural development, such as the Antelope, Majave River, Coachella, -ko- Ingjerial, Yuma, and Palo Verde Valleys. In other areas of lesser develop- ment, only those classes of land use requiring water service were mapped. Hydrologic studies in these lesser developed areas were considered to be less critical since it is generally assumed that precipitation on most of these undeveloped portions would be consumed by native vegetation or evaporated. Categories of Land Use For purposes of analysis and presentation, the various types of land use in water service areas were grouped in two major categories; Urban and Suburban, and Irrigated Agriculture. These two major categories were then subdivided into the several classes of land use, based on water re- quirements. The objective of this classification was to group the various types of land use into classes, each of which were considered to require similar amounts of water. The two major categories and the specific classes of land use included in each of these categories are as follows: Water Service Area Urban ■ and Suburban Residential Single and multiple family houses and apartments, rest homes, trailer parks, and residential subdivisions under construction at time of survey. Recreational residential Weekend and simmier home tracts within a primarily recreationad area. Commercial All classes of commercial enterprises, including strip commercial and down- town commercial areas, schools, and hospitals. Industrial All classes of industrial land use Involving manufacturing processing, and packaging, but excluding extractive industries (oil, sand, and gravel), air fields, storage, distribution and transportation facilities. .kl- Unsegregated urban and subxirban axea .... Dairies, farmsteads, livestock rajiches, parks, cemeteries, and golf courses. Included nonwater- service area Oil fields, tank farms, vacant lots, quarries, gravel pits, warehouses and storage yards, railroads, public streets, and landing strips of air fields. Irrigated Agriculture Alfalfa Hay, seed, and pasture. Pastxire Irrigated grasses and legumes other than alfalfa used for livestock forage . Citrus and subtropical . . Oranges, lemons, grapefniit, tangerines, avocados, dates, and olives. Truck crops Vegetables of all varieties, melons, flower seed, and nursery crops. Field crops Cotton, sorghums, flax, sugar beets, and field corn. Deciduous fruits and nuts . All varieties of deciduous fruits and nuts. ■qnaii grain Barley, wheat and oats. Vineyards All varieties. Included nonwater- service area Public highways and roads, farm access roads, canals, drainage ditches, and other inclusions not devoted to crop production, including idle, and abandoned lands. The classes of land use given here are similar to those used in Biilletin No. 2, except that schools, previously included in "unsegregated urban and suburban area", are classified herein as "commercial"; in addition. -42- parks, golf courses, and cemeteries, classified as "irrigated pasture" in iy50 are included under "unsegregated urban and suburban area" in this report. In delineating land use classes in the field, no attenpt was made to exclude such items as streets, roads, railroads, power line right-of- ways, and other essentially nonwater-using lands occurring within the surveyed areas. Instead, these land uses were classified as "included nonwater service areas", and were extracted from overall land use totals by applying to each major land use class a percentage value appropriate for that class. The major classes of land use and appropriate reduction factors are presented in Table 5- The net acreage values used in the tables summarizing land use represent the gross acreage values minus those portions of the gross values which have been deducted for these "included nonwater service areas." TABLE 5 FACTORS FOR REDUCTION OF GROSS AREAS TO NET WATER SERVICE AREAS Land use ■.Percent deducted :from gross area Residential 25 Commercial 35 Industrial manufacturing 25 Parks, cemeteries, and golf courses 15 Farmsteads, feedlots, dairies 10 Irrigated agriculture 5 -43- Many areas located vrithln military reservations throughout the area of investigation were restricted to entry and thus could not be mapped in the field. Hiose portions of military reservations which were mapped indicated that the land uses therein were primarily nonwater-using developments, such as paved landing areas, storage depots, or gunnery ranges. Consequently, the land use occurring within such military reser- vations is not included in the summary tables. Results of Land Use Survey The results of the land use survey indicate that about 878,000 acres of land in the southeastern desert area required water service in 1958. As shown on Table 6, which summarizes land use on the basis of hydro- graphic units, about 801,000 acres of this total were included in the irri- gated agriculture classes, while 77,000 acres were in the urban and suburban classes. Table 6 also shows that about 823,000 acres or approximately 9h percent of the total lands requiring water service are located within four hydxographic units: the Antelope Valley, Coachella Valley, Inperial Valley, and Colorado River units. Table 7 summarizes land use by counties in the area of investigation. 1 Details of the patterns of land use in the survey area are given on Plates 3A, 3B, 3C, and 3D, "Present Land Use". Although the acreages of nonwater service areas within urban and suburban and irrigated agrl- | culture areas are shown individually on Tables 6 and 7, they were not differentiated on the plates. Water service to about 728,000 acres, or approximately 83 percent of all lands within the area of investigation, is provided by four major water agencies; the land use in the service areas of these four agencies -kk- BLE 6 rHE SOUTHEASTERN DESERT AREA IN I958 TABLE 6 acres Hydrographic units tynine : Coachella Salton : Imperial : Colorado : Lanfair : ilms Valley : Sea : Valley : River : Valley : Totals .SJtO 5,81+0 300 3,100 1,070 70 17.050 ,2lf0 2,850 230 60 ll+,310 litO 970 UO 680 2I+0 30 3,630 80 10 580 60 920 210 1,680 110 12,310 980 50 17,390 ,930 11,U20 690 16,670 2,1+10 150 53,300 ,830 it,61tO 350 7,720 2,150 180 22,960 ,160 16,060 1,01+0 2l+,390 l+,56o 330 77,260 ,150 5,900 1,610 135,860 25,870 211+,680 600 2,130 1+70 2,500 8,860 22,010 13,860 90 1,760 530 16,21+0 10 8,730 1+20 2U,790 h,250 39,61+0 7,980 380 100,310 26,130 11+0,91+0 350 60 100 30 2,170 350 2,850 580 110,790 6,1+1+0 137,880 12,330 2,000 80 20 _0 1I+, 1+1+0 ,110 51+, 130 5.610 376,190 72,130 588,000 1^,810 110 89,530 16,580 118,980 230 8,750 1,350 66,680 12,1+30 93,?20 ,31*0 67,690 7,070 532,1+00 101,11+0 _0 800,900 ,100 83,750 8,110 556,790 105,700 330 878,160 .1+5- Many axeas located within military reservations throughout the area of investigation were restricted to entry and thus could not be mapped in the field. Those portions of military reservations which were mapped indicated that the land uses therein were primarily nonwater-using developments, such as paved landing areas, storage depots, or gunnery ranges. Consequently, the land use occurring within such militeiry reser- vations is not included in the summary tables. Results of Land Use Survey The results of the land use survey indicate that about 878,000 acres of land in the southeastern desert area required water service in 1958. As shown on Table 6, which summarizes land use on the basis of hydro- graphic units, about 801,000 acres of this total were included in the irri- gated agriculture classes, while 77,000 acres were in the urban and suburban classes. Table 6 also shows that about 823,000 acres or approximately 9'+ percent of the total lands requiring water service are located within four hydrographic units: the Antelope Valley, Coachella Valley, Injjerial Valley, and Colorado River units. Table 7 stunmarizes land use by counties in the area of investigation. Details of the patterns of land use in the survey area are given on Plates 3A, 3B, 3C, and 3D, "Present Land Use". Although the acreages of nonwater service areas within urban and suburban and irrigated agri- cxilture areas are shown individually on Tables 6 and 7, they were not differentiated on the plates. Water service to about 728,000 acres, or approximately 83 percent of all lands within the area of investigation, is provided by four major water agencies; the land use in the service areas of these four agencies -kk- i TABLE 6 LAND USE IN HYDROGRAPHIC UNITS OF THE SOUTHEASTERN DESERT AREA IN I958 In acres TABLE 6 HydroRraphic units Nature and class of land use : Death Mojave : Antelope :rwentynine: Coachella: Salt on ; Imperial : Colorado : Lanfair : Valley River : Valley : Palms : Valley : Sea : Valley : River : Valley : Totals WATER SERVICE AREA Urban and Suburban Residential 730 1,350 3,250 1,340 5,840 300 3,100 1,070 70 17.050 Recreational residential 30 900 10,240 2,850 230 60 14,310 Commercial 130 510 890 140 970 40 680 240 30 3,630 Industrial 100 40 50 80 10 580 60 920 Unsegregated urban and suburban area 100 450 1,500 210 1,680 110 12,310 980 50 17,390 Subtotals 1,060 2,380 6,590 11,930 11,420 690 16,670 2,410 150 53,300 Included Nonwater-Service Area 1,11+0 1,760 4,190 1,830 4,640 350 7,720 2,150 180 23,960 Gross Urban and Suburban Area 2,200 4,140 10,780 13,760 16,060 1,040 24,390 4,560 330 77,260 Irrigated Agriculture Alfalfa U,820 7,060 32,410 1,150 5,900 1,610 135,860 25,870 214,680 Pasture 370 1,960 5,120 600 2,130 470 2,500 8,860 22,010 Citrus and subtropical 13,860 90 1,760 530 16,240 Truck crops 20 130 1,290 10 8,730 420 24,790 4,250 39,640 Field crops 2,6hO 1,290 2,210 7,980 380 100,310 26,130 140,940 Deciduous fruits and nuts 90 1,540 350 60 100 30 2,170 Small grains 1,990 310 14,570 350 2,850 580 110,790 6,440 137,880 Vineyards 10 12,330 2,000 80 20 _g 14,440 Subtotals 9,840 10,850 57,140 2,110 54,130 5,610 376,190 72,130 588,000 Fallow 1,400 1,030 5,520 4,810 110 89,530 16,580 118,980 Included Nonwater-Service Area 560 580 3,340 230 8,750 1;350 66,680 12,430 93,920 Gross Irrigated Agriculture 11,800 12,460 66,000 2,340 67,690 7,070 532,400 101,140 _g 800,900 GROSS WATER SERVICE AREA 14,000 16,600 76,780 16,100 83,750 8,110 556,790 105,700 330 878,160 .45- I i V •H (0 ■H pq CO (U H Q (U 5| a u fO o m to a i o IfN, o rovo On ro R| SO o o rnrn H OJ CVJ oo oil O Q O o\^ en rOMD H VO CVJ rH o o o g o ITN (T1 t— rH t— I O Q O O O 0\r^ t~ en OJ H Q O O O O 05 OJ l/^a5 •H to SCO fn rH CA ITN t-i O ^- co •» o\ o\ s o 8 m n p O O m ITNCO -7\ s o CO s^ CO coco •k •* •< H C7SC0 d H H H O 0\C- o o C7\0 •» * CVJ H ICO o a\ O LTN OOH •■ ."• _^ O lA OJ 8 O O o a\ S CO 0\ H CO o o ro oo ro ro O ro _ O lA 00 cd -kj- is shown on Table 8. With the exception of approximately 19,800 eicres in the Coachella Coimty Water District which receives water from wells, the entire service area of these four water agencies is dependent upon water from the Colorado River. Change in Land Use There were major increases in the area requiring water service between 1950 and 1958 in the area of investigation. As shown on Table 9, the gross urban and suburban water service areas increased from about 27,000 acres in 1950 to 77,000 acres in 1958, vrtiile the gross agricultural water service areas increased from about 6^+3,000 acres in 1950 to 801,000 acres in I958. Both irrigated agriculture and urban and sxzburban areas expanded into previously undeveloped land areas, and the gross area re- quiring water service increased from 670,000 acres in I95O to 878,000 eicres in 1958, an overall increase of about 3I percent. There was some decline in irrigated acreages in Antelope Valley and Majave River Valley units. This decline and other changes are delin- eated on Plate h, "Change in Land Use, Antelope Valley and Vicinity, I95O to 1957, " and Plate 5, "Change in Land Use, Coachella and Palo Verde Valleys and Vicinities, I95O to I958." Changes in land use occurring in each hydrographic unit are discussed in the following sections. Death Valley Itoit (6-10) The gross water service area in the Death Valley Itait increased about 2,500 acres, or approximately 22 percent, between I95O and 1958. Approximately 1,000 acres of this total expansion were in urban and suburban development, and 1,500 acres were irrigated agriculture. .h8- ct O P •H O 3 M-P m -H m ts M t) a -d o -p ^H -H O 4) P -H > Oj ^H h hOP o o Ti m a a£° M O a 9 03 r-l O -P i/\ •H -P -ri g ON U OS U H lU MP 1 B Irri Dls e ^ o g „ •• rf ^ to Q) ^ ^ 1) ^1 Vail ater ct § s § 1 1 a 11a ty W stri w 1 ache Coun Di o 1 8 ^, __ O B to W 13 m 3 O to m 0) 8388^ CT\ O C\J o :&8. 1^ OJ > ir\ OJ ir\ t^ oo VO H rH OO CO r-\ H 3>^ ^ W O S §1 l/N H^^roHlBo-lONW HI H I CM iACT\OJr-lf- t- O O O O O H OOMD H ir\ i-l 00 8° 41 ^ O t— m oT 8. CM 2 VO 9 I (0 o QOOOOOOO ro oo O -* fO QQOQOQOO \j5ovoa\Hoa\co 00 LfN t^ t— OO rH t-- ITv OJ CO H I J- OJ o 8P O Q O Q O oi ro a\ t-<5 "" o _ -- ro _ _ _ •\ "v "s •* "^ ir\H roco 1>- 4) ■P ■^ o SI ■d 4) P o •H 8 ■§ I P CO l«H m ta O O g bOjg P d 4) CJ to 4) ^ p MTi -B ri >> P S O H -H r- 4) CO P g 4) CJ fl pLi O Eh S O CJ\ H CO J- H ^ CO 8 c/N O O ootfS ir\\0 CJWO CO VO R cSS S^ H CPvCM cnt~ •^ •* ^ CO -*C0 VO OJ VO f- ir\ (d o m I 4) ■P -d 4) II 23 ■CO CJvOJ VO C^ CO CO CT\ OJ OJ ro rH H 8g OJ ITN CO CO OJ VD ro lA ir\ UN -U9- Mojave River Unit (6-11) The Mo J awe River Unit experienced only a minor change in gross area requiring water service, increasing from 15,800 to l6,600 acres betvfeen 1950 and 1957 • Although the urban and suburban area increased substantially from 1,900 acres in I950 to l4-,100 acres in 1957, or II6 per- cent, the Irrigated agricultural area decreased 10 percent from 13,900 acres to 12,500 acres in the same period. The largest decreases in irri- gated acreage were alfalfa and truck crops. Antelope Valley Unit (6-12) The gross urbtui emd siiburban area reqxiiring water service in the Antelope Valley Unit increased from about 2,000 acres in I95O to 10,800 acres in 1957^ or nearly five and one-hal f times, while the irrigated agri- cultural acreage decreased from 72,700 acres to 66,000 acres, or nine percent. The largest decrease in Irrigated agricultural acreage occurred in alfalfa, ^ich dropped from 62,100 acres in 195O to 32,JtOO acres in 1957* The acreage of deciduous fruits and nuts also decreased, but acreages of small grains, field crops, and truck crops increased siibstantially. Twentynine Pains Unit (7-l) A large increase in the gross urban and suburban area occurred in the Twentynine Palms Unit. In 1950, about 8OO acres were subject to this land use, but by I958 this acreage had increased to 13,800 acres, or a little more than I7 times. However, a large portion of this expansion (10,200 acres) was classified in the recreational residential category. This category consists of small buildings occirpied essentially during vacations or weekends on large (2.5 acres or more) lots. Irri^ted agri- culture increased only slightly during the same period, going from 2,000 acres to 2,300 acres, an increase of about I5 percent. I I CoacheJ-La Valley Unit (7-2) The Coachella Valley Unit experienced an Increase of k'JfdOO acres in gross water service axea tetween 1950 and 1958 • Urban emd suburban acreage increased from 4,900 acres in 1950 to l6,100 acres in 1958> and of this 11,200 acre increase, 2,800 acres were in recreational residential development. The gross irrigated agricultural acreage increased from 31,100 acres in 1950 to 67,700 acres in I958, a gain of 36,600 acres, or about 118 percent. All categories of crops showed substantial acreage gains with the exception of deciduous fruits and nuts. Approximately 60,200 acres of this total irrigated area are served by water from the Colorado River, but the remaining 7,500 acres are dependent entirely on ground water for water supplies. Salton Sea Unit (7-3) The gross water service area in the Salton Sea Unit showed an Increase of 5,300 acres diiring the 8-year period. Urban and suburbem acreage increased from 3OO acres to 1,000 acres, or 3.3 times with approx- imately 200 acres of this 700 acre increase occurring in recreationail type residential development. The irrigated agricultural acreage increased from 2,500 acres in I95O to 7,100 acres in 1958, with alfalfa acreage undergoing the greatest increase. Imperial Valley Unit (7-4) Irrigated agriculture in the Imperial Valley Unit expanded from a net area of 363,800 acres in March 1952 to 376,200 acres in March 1959, a 3 percent increase. During this period, the acreage planted in alfalfa decreased substantieilly vrtiile acreages of field ci\jps and small grains .51- increased. In contrast to this small increase, the gross urban and suburban area increased from 12,200 acres to 24,^400 acres, or 100 percent. Colorado River Unit (7-^) A large increase in irrigated agricultural acreage occiorred in the Colorado River Unit; the 65,200 acres in 1950 had been expanded to 101,100 acres by 1953^ a growth of about 55 percent. Field crops and pasture both increased in acreage, but alfalfa acreage decreased somewhat. During the 8-year period, the acreage increase in urban and suburban development amounted to only about l8 percent, with growth from 3j900 acres in 1950 to 4,600 acres in I958. Lanfair Valley Unit (7-6) Significant changes have not occurred in the Lanfair Valley Unit between 1950 and 1958. The gross urban and suburban water service area remained at about 30O acres, and irrigated agriculture does not exist in this unit. Supplemental Besurveys of Multiple Cropped Areas In the southern portion of the investigational area, the short mild winters make the raising of crops possible on a year-roiond basis. In these intensively farmed areas, field mapping conducted during the summer season characteristically reveals large acreages of land in a fallow or between-crop condition. Under normal cropping practices, it was assumed that a large portion of this fallow land would be subsequently planted at some point during the study period. The net water use of fallow lands is negligible and therefore estimates of net water use based only on data -52- TABLE 9 olorado River ; Tanfalr Valley ; Totala 1950 ; 1958 : 1950 : 1958: 1950 : 1958 3,900 4,560 300 330 27,480 77, 260 0,800 3,500 200 0,100 8,200 b,900 25,870 8,860 530 4,250 26,130 30 6,440 20 _g _o 282,880 10,020 10,310 53,150 91,410 6,390 93,010 9,880 214,680 22,010 16,240 39,640 140,940 2,170 137,880 14,440 3,700 72,130 557,050 588,000 = 16,580 81,120 118,980 1,500 12,430 4,600 93,920 5,200 101,140 642, no 800,900 9,100 105,700 300 330 670,250 878,160 -53- increased. In contrast to this small increase, the gross lorban and suburban area increased from 12,200 acres to 2l+,UO0 acres, or 100 percent. Colorado River Unit (7-^) A large increase in irrigated agricultural acreage occurred in the Colorado River Unit; the 65,200 acres in 1950 had been e>rpanded to 101,100 acres by 1953, a growth of about 55 percent. Field crops and pasture both increased in acreage, but alfalfa acreage decreased somewhat. During the 8-year period, the acreage increase in urban and suburban development amounted to only about l8 percent, with growth from 3>90O acres in 1950 to 4,600 acres in I958. Lanfair Valley Unit (7-6) Significant changes have not occurred in the Lanfair Valley Unit between 1950 and I958. The gross urban and suburban water service area remained at about 30O acres, and irrigated agriculture does not exist in this unit. Supplemental Resurveys of Multiple Cropped Areas In the southern portion of the investigational area, the short mild winters make the raising of crops possible on a year-round basis. In these intensively farmed areas, field mapping conducted during the summer season characteristically reveals large acreages of land in a fallow or between-crop condition. Under normal cropping practices, it was assumed that a large portion of this fallow land would be subsequently planted at some point during the study period. The net water use of fallow lands is negligible and therefore estimates of net vater use "osised only on data -52- WATEB SERVICE ABEA Gross Urban and Suburban Area* Irrigated Agriculture Alfalfa Pasture Citrus tmd subtropical Truck crops Field crops Deciduous fruits and nuts Small grains Vineyards Subtotals Fallow Included Nonwater-Service Area Gross Irrigated Agriculture GROSS WATER SERVICE AREA TABLE 9 LAUD USE C(» three supplemental resurveys were conducted in certain predetermined areas in order to determine the subsequent use of this fallow acreage. These resurveys were made during Noveinber 1958 and February and May 1959 in the Coachella, Borrego, and Palo Verde Valleys, During each of the resurveys, the nature and areal extent of crops planted in this fallow acreage, subsequent to the June 1958 survey, were determined. Field mapping during these resurveys indicated that portions of the fallow acreages were planted, then subsequently replanted to different crops or allowed to revert to fallow conditions. However, during the analysis of the resxirvey data from which the percentages shown in Table 10 were derived, these factors were not considered. Instead, the nature and areal extent of crops were considered on a cumulative basis. Under this method, the first crop mapped on a previously fallow parcel was used as the basis for deriving unit use values, and removed that parcel from the fallow classification for the remainder of the study period. It should be pointed out here that the increased use of water resulting from multiple cropping practices, including fallow periods between crops, was considered in estimating average unit values of water use for truck crops. Analysis of the data from the resurveys indicates that in the Coachella, Borrego, and Palo Verde Valleys, 19 percent, 84 percent, and 8 percent, respectively, of the total area indicated as fallow during the June survey remained fallow throughout the succeeding resurveys. The -55- remaining land, which had been mapped fallow in June 1958 in these valleys, was found during the subsequent re surveys to be planted to the various crops in the percentages shown on Table 10. TABLE 10 DISPOSITION DURING RESURVEY PERIOD OF ACREAGE FOUND FALLOW IN SUMMER 1958 (in percent of June fallow acreage) land use Area Res -urveyed Nature of : Coachella : : Valley : Borrego Valley : Palo Verde Valley Area remaining fallow all year 19 84 8 Area planted and crop Alfalfa 6 23 Truck crops 45 Ik 37 Field crops 19 10 Small grains 11 2 22 Total 100 100 100 The values given in Table 10 were used as the basis for distri- buting the fallow acreages determined from the June, 1958, survey into the appropriate crops for determining water requirements. However, the acreage values presented in Tables 6, 7, 8, and 9> and in Appendixes C and D, vrtiich show the land use at the time of the principal survey, have not been modified to reflect these percentage increases. The values for Palo Verde Valley were used for the entire Colorado River hydrographic unit. In the Sal ton Sea hydrographic unit the only fallow acreage mapped occurred in Borrego Valley. Fallow lands are also found in the Death Valley, ^fc)jave River and Antelope Valley hydrographic units, as indicated on Table 9 and other ■56- summary tables. It is recognized that portions of this acreage may be used to produce irrigated crops during the fall and winter months, however, lower teii5)eratures generally prevail in these higher desert areas and they are not usually considered suitable for year-round cultivation. Therefore, resurveys were not conducted in these units and no evaluation was made of the extent that crops were grown on this fallow acreage. As mentioned previously, supplemental land use surveys were also conducted by personnel of the Imperial Irrigation District, for land use within that district. Although the results of these supplemental surveys are presented in Appendix B, these data did not require further evaluation or discussion since the methods used in developing net water use, which are described in the next chapter, did not require their use. -57- CHAPTER IV. WATER USE The land ai-eas occupied by various types of water-using develop- ments in the southeastern desert area were described in Chapter III. Since this land use was classified on the basis of water requirements, it is possible to apply appropriate unit values of water use to estimate the 1953 levels of water use in this area. This level of use must be known so that adequate programs of water resource development can be planned smd implemented to meet the needs of the future growth of the area. This chapter defines what is meant by water use and presents the methods used in estimating water use, g'ves the unit values of water use, and presents estimates of 1958 water requirements. Definition of Water Use The term water use is employed in the broadest sense to include all uses of water by nature under native conditions and by man in his modifications of those natural conditions. It implies the application of water to any one, or all, of innumerable kinds of uses, both consumptive and nonconsuraptive. Consumptive use includes the water from any source utilized in the process of vegetative growth, such as transpiration and the building of plant tissue, and the water evaporated from the soil around the plant and foliage, as well as from water surfaces. It also includes the water consumed or evaporated by urban and nonvegetative types of land use. In addition to the consumptive use of water as defined above, there may be irrecoverable losses incidental to such use. These -59- irrecoverable losses include such items as deterioration in water quality to the point where the water is unsuitable for reuse, disposal or seepage of the unconsumed water to bodies of unsuitable quality including the Salton Sea, and disposal or seepage of the unconsumed water in such a manner as to be uneconomical of recapture for use. The water for consumptive use is obtained from two general sources: natural sources including direct precipitation and surface runoff, and, as a specietl case, from a high ground water table; and man- developed sources, that is, water applied through the activities of man. Water furnished from this latter source is termed "applied water." Man applies water to satisfy the consumptive use needs in excess of that supplied from natural sources. However, as a practical matter, the quantity of water applied is usually in excess of the consumptive use of applied water, and that portion of the water applied to any use that is not consumed or irrecoverably lost remains part of the water supply. In evaluating the overall needs for water in an area, it is necessary to determine the portion of the applied water that is consump- tively used. That portion of the applied water that is consumptively used and irrecoverably lost is known as the "net water use." The difference between the applied water and the net water use is the amount of applied water that is subject to reuse as a part of the common supply. Methods of Estimating Water Use It follows from the previous discussion that m areas where none of the applied water becomes available for reuse, it is possible to determine the net water use by measuring the totsil water applied. On -60- . the other hand, in areas where a portion of the applied water hecomes available for reuse, present technology is generally inadequate to measure this volume of return flow of reusable water. The net water use in these areas must be determined in another manner, therefore an indirect method is used. Using the indirect method commonly eaiployed, estimates of net water use are obtained by multiplying the areas of the various classes of water using developments by appropriate average values of unit water use. These unit values of water use reflect average conditions of precipitation and the normal practices associated with urban water distribution and irrigated agriculture. Variations from normal or average in these factors during the specific year that a land use survey is conducted may result in a difference between the estimated and actual water use during that year. Despite this possibility, it is considered that the procedures used in this survey are adequate, and that the figures on current levels of water use are reasonable. Furthermore, it is believed that these estimates of net water use are sufficiently sound to permit their use in determining the adequacy of presently available water supplies and for planning for such additional supplies as will be necessary to meet current or expected future deficiencies. Unit Values of Water Use A complete discussion of the techniques employed in the deri- vation of unit values of water use is contained in Bulletin No. 2; con- sequently, only a very general discussion of those techniques is undertaken here. The unit water use values are divided into the general categories of urban and suburban, and irrigated agriculture use values. -61- Urban and Suburban Water Use Values A review of the unit values of urban and suburban vrater use developed for Bulletin No. 2 indicated that, in generaJL, the values derived in 1950 were still the best estimates available, and these values were used in the derivation of the 1953 levels of net water use on urban and suburban lands that are shown on Table 11. TABLE 11 ESTIMATED MEAN SEASONAL UNIT VALUES OF NET WATER USE ON URBAN AND SUBURBAN LANDS, SOUTHEASTERN DESERT AREA (in feet of depth per unit of area) Hydrographic unit : Net water use Death Valley 0.3 Mojave River 1.2 Antelope Valley 1.0 Twentynine Palms 1.2 Coachella Valley 2.3 Salton Sea 1.6 Imperial Valley 1.7 Colorado River 1.5 Lanfair Valley 0.3 Mean seasonal unit values of water use on urban and suburban lands in the desert areas of California were estimated for Bulletin No. 2 from records of measured water deliveries obtained from private and public service agencies. In areas where sewage disposed from urban and suburban areas returns to the ground water body, unit values of water use were computed by deducting the estimated quantity of such return from the -62- amount of water delivered to the area. In other areas where sewage is discharged to the point of final disposal without opportunity for reuse, the gross delivery was taken as a measure of the net water use. In the Coachella Valley, particularly in the vicinity of Palm Springs, Indio and Desert Hot Springs, much land has been developed to a "spa" or high grade recreational use, and a review of Bulletin No. 2 indicated that the unit value of water use for this type of development should be revised upward because of increased water use. Accordingly, the unit value for this valley was increased from 1.7 to 2.3 acre-feet per acre, based on an analysis of water delivery values which were obtained from water service agencies in the valley, and other factors of water use and disposal previously described. It will be noted that the tables of land use presented in Chapter III differentiated between urban residential and the recreational residential classes. Within the area encompassed by this investigation, this latter class of land use generally consisted of small dwellings on 2-1/2 to 5-acre tracts, usually occupied less than 25 percent of the time. A study was made to evaluate the water requirements of this class and it was found that water supplies were usually obtained from agencies which truck water to the dwellings at a cost of about -75 cents a gallon, or that water was carried in by the recreationists, either from their permanent dwellings or from nearby service stations. Such supplies were used for drinking, cooking, and essential washing pui-poses only. The total seasonal volume of water used was determined to be very small (on the order of 0.01 acre-feet/acre) and was, therefore, neglected in the determination of water requirements in this report. -63- Irrigated Agriculture Water Use Values The unit value of consumptive use of applied water for each of the Irrigated crop classes employed In Bulletin No. 2 was estimated by a modification of a method developed by Harry F. Blaney and V/ayne D. Griddle of the United States Department of Agriculture. In the present investigation as in Bulletin No. 2, the increased use of water, result- ing from multiple cropping practices in some localities, was considered in estimating average unit values of water use for truck crops. The values thus derived are presented in Table 12. The values shown in Table 12 represent estimates of the average consumptive uses derived from applied water and from precipitation by thp various types of irrigated agriculture. As pointed out before, in the derivation of the net water use for any given year the volume of applied water required is based on the assumption that the precipitation for the season is approximately equal to the long-time mean. However, as dis- cussed earlier, the use of applied water in irrigated agriculture will actuailly be somewhat larger or smaller in individueil years, varying inversely with the amount of rainfall. A similar effect also occurs in the instance of urban use, but variations of rainfall from year to year have a lesser effect upon the use of applied water on urban lands than on irrigated lands. However, it may be noted from the data presented in Table 12 that the beneficial value of precipitation is of minor magnitude for either use. Net Water Use Estimates of the level of net water use in the southeastern desert area under 1958 conditions of development were made by the direct .■6k- ILE 12 ALUES OF CONSUMPTIVE USE OF WATER OUTHEASTERN DESERT AREA h per unit of area) TABLE 12 Antelope Valley Consumptive use ,ied :Precipi-: ler : tat ion : Total Coachella Valley, Salton Sea, Imperial Valley, and Colorado P.iver Consiflirptive use Applied :Precipi- water : tation : Total Twentynine Paljns and Lanfair Valley Consumptive use Applied rPrecipi-: water : tation : Total [O 0.6 e 0.6 0.6 0.6 3.6 4.2 0.3 3.^^ 5.0 0.3 ~ U.O 0.3 " 6.0 0.3 2.0 3.0 0.3 — 3.0 0.3 2.6 2.5 0.3 5-3 ^.3 6.3 3.3 3.3 2.8 2.9 2.7 1.5 0.3 0.3 0.3 3.2 3.0 1.8 0.6 2.1 2. it 0.3 2.T 0.6 0.6 0.6 2.8 l.U 3.0 2.3 1.8 3.6 0.3 0.3 0.3 2.6 2.1 3.9 2.2 1.0 0.3 0.3 2.5 1.3 -65- Irrigated Agriculture Water Use Values The unit value of consumptive use of applied water for each of the irrigated crop classes employed in Bulletin No. 2 was estimated by a modification of a method developed by Harry F. Blaney and V/ayne D. Griddle of the United States Department of Agriculture. In the present investigation as in Bulletin No. 2, the increased use of water, result- ing from multiple cropping practices in some localities, was considered in estimating average unit values of water use for truck crops. The values thus derived are presented in Table 12. The values shown in Table 12 represent estimates of the average consumptive uses derived from applied water and from precipitation by the various types of irrigated agriculture. As pointed out before, in the derivation of the net water use for any given year the volume of applied water required is based on the assumption that the precipitation for the season is approximately equal to the long-time mean. However, as dis- cussed earlier, the use of applied water in irrigated agriculture will actually be somewhat larger or smaller in individual yeeirs, varying inversely with the amount of rainfall. A similar effect also occurs in the instance of urban use, but variations of rainfall from year to year have a lesser effect upon the use of applied water on urban lands than on irrigated lands. However, it may be noted from the data presented in Table 12 that the beneficial value of precipitation is of minor magnitude for either use. Net Water Use Estimates of the level of net water use in the southeastern desert area under 1958 conditions of development were made by the direct „6k- TABLE 12 TABLE 12 ESTIMATED MEAN SEASONAL UNIT VALUES OF CONSUMPTIVE USE OF WATER ON IRRIGATED LANDS, SOUTHEASTERN DKiERT AREA (in feet of depth per unit of area) Death Valley Mojave River Antelope Valley Coachella Valley, Salton Sea, Imperial Valley, and Colorado River Twentynine Palms and Lanfair Valley Type of land use Consunrptive use Consumptive use Consumptive use Consumptive use Con sumptive use Applied water :Precipi- : : tation : Total Applied water :Precipi-: : tation : Total Applied water :Precipi- : tation ; Total Applied :Precipi- water : tation : Total Applied water :Precipi- : : tation : Total Alfalfa 3.0 O.k 3.'+ 2.8 0.1+ 3.2 3.0 0.6 3.6 1+.2 0.3 h.5 2.9 0.3 3-2 Pasture 2.8 0.1+ 3.2 2.7 0.1+ 3.1 2.8 0.6 i.h 5.0 0.3 5.3 2.7 0.3 3.0 Citrus — — — — — ~ — — — l+.O 0.3 h.3 — — " Dates — ~ — — — ~ — — — 6.0 0.3 6.3 — — — Truck crops 1.6 0.1+ 2.0 1.5 0.1+ 1.9 1.1+ 0.6 2.0 3.0 0.3 3.3 1.5 0.3 1.8 Cotton — — — ~ ~ ~ — — — 3.0 0.3 3.3 — — — Sugar beets 2.2 O.k 2.6 2.2 0.1+ 2.6 2.0 0.6 2.6 2.5 0.3 2.8 — — — Miscellaneous field crops 1.6 0.1+ 2.0 — — 2.1 1.5 0.6 2.1 2.1+ 0.3 2.7 — — -- Deciduous fruits and nuts 2.2 0.1+ 2.6 2.1 0.1+ 2.5 2.2 0.6 2.8 2.3 0.3 2.6 2.2 0.3 2.5 Small grains 1.1 0.1+ 1.5 0.9 0.1+ 1.3 0.8 0.6 1.1+ 1.8 0.3 2.1 1.0 0.3 1-3 Vineyards 2.h 0.1+ 2.8 2.3 0.1+ 2.T 2.1+ 0.6 3.0 3.6 0.3 3.9 — — — -65- and indirect methods discussed previously. For most of the area of investigation, net water use was estimated by applying mean seasonal unit values of consumptive use to the areas of each class of land use. This method was used for land that overlies or is tributary to free ground water basins, as in Borrego Valley, and for land which is irrigated by diversions from the Colorado River where the drainage returns to the river for reuse, as in Palo Verde Valley. In those areas of the Imperial and Coachella Valleys which are serviced with Colorado River water, the quality of the applied water and the condition of the soil are such that sufficient water must be applied and carried away through subsurface drainage systems to maintain the salt concentration in the soil solution at limits required for plant growth. The drainage water, essentially unconsumed water of such poor mineral quality as to preclude its reuse, flows directly into the Salton Sea. In such areas, the net water use was assumed to be equal to the applied water, and was based on measurements of quantities of diverted Colorado River water passing Drop 1 on the All American Canal for the Imperial Valley, and Mile Post 87 on the Coachella Canal for Coachella Valley. The estimated levels of mean seasonal net water use in hydro- graphic units of the southeastern desert area for 1958 conditions are presented in Table 13; values estimated for 1950 conditions are also presented in this table for purposes of comparison. As previously indicated, the unit values used to derive the levels of net water use shown on Table 13 represent the optimum applied water requirements for the various classes of land use under average .67- TABLE 13 ESTIMATED LEVELS OF NET WATER USE IN THE SOUTHEASTERN DESERT AREA FOR CONDITIONS OF DEVELOPMENT IN 1950 AND 1958* Quantity in Acre-feet Hydrographic unit 1950 195c3 Difference DEATH VALLEY UNIT Irrigated Lands Urban - Suburban Areas TOTALS MOJAVE RIVER UNIT 23,000 300 23, 300 21,900 7C0 22,600 1,100 tfOO 700 Irrigated Lands Urban - Suburban Areas 31,400 2,6oo 27,700 it, 900 - 3,700 2,300 TOTALS 3^^,000 32,600 - 1,'UX) AOTELOPE VALLEY UNIT Irrigated Lands Urban - Suburban Areas 200,000 2,200 131,700 9,500 -68, 300 7,300 TOTALS 202,200 llH,200 -61,000 TWENTYNINE PALMS UNIT Irrigated Lands Urban - Suburban Areas 5,6oo 1,200 5,300 3,500 300 2,300 TOTALS 6,800 8,800 2,000 coa(jhj>;t,ta valiky unit Irrigated Lands Urban - Suburban Areas 119,000 7,500 356,600 30, 500 237,600 23,000 TOTALS 126, 500 387,100 260,600 SALTON SEA UNIT Irrigated Lands Urban - Suburban Areas 8,900 300 20,600 1,100 11,700 800 TOTALS 9,200 21,700 12, 500 -68- ESTIMATED LEVELS OF NET WATER USE IN THE SOUTHEASTERN DESERT AREA FOR CONDITIONS OF DEVELOPMENT IN 1950 AND 1958* (continued) Quantity in Ac re -feet Hydrographic unit 1950 : 1958 Difference IMPERIAL VALLEY UNIT Irrigated Lands Urban - Suburban Areas 2,790,000 15,^+00 2,70U,200 26,700 -85,300 11, 300 TOTALS 2,805,1+00 2,730,900 -71+, 500 COLORADO RIVER UNIT Irrigated Lands 218,000 307,000 89,000 Urban - Suburban Areas 3,300 6,200 2,900 TOTALS 221,300 313,200 91,900 LANFAIR VALLEY UNIT Irrigated Lands Urban - Suburban Areas 100 100 TOTALS 100 100 TOTAL INVESTIGATIONAL AREA Irrigated Lands 3,395,900 3,575,000 179,100 Urban - Suburban Areas 32,900 83,200 50, 300 GRAiro TOTALS 3,^28,800 3,658,200 229,1+00 ♦ Net water use is that portion of the applied water consumed and irrecoverably lost. It does not include the consumptive use of precipitation. conditions of rainfall and climate. Available data from precipitation stations in the desert area indicate that precipitation over the area of investigation during 1950 was about UO percent of normal, based on the -69- 50-year period I897-98 through I9U6-U7. On the other hand, during I958 precipitation was about 150 percent of the 50-year normal figure. The estimates of levels of net water use shown on Table 13 are, therefore, probably on the low side for 1950 and on the high side for 1958 as conipared to actual water use in those years. However, the total depth of precipitation in desert areas is usually quite small even during wet years, thus the values given on Table 13 are considered to be reasonable estimates of changes in water use. In general, the data presented in Table 13 indicate that changes in net water use reflect the changes in land use described in Chapter III. The overall net water use for the area increased about seven percent. Urban requirements increased substantially over 100 per- cent in nearly all areas, but at the present time they constitute only about two percent of the total net water requirements of the area. On the other hand, water requirements for agriculture decreased in a number of the basins which are primarily dependent on ground water supplies. -70- CHAPTER V. SUMMARY AND CONCLUSIONS The results of the 1958 land and water use survey of the desert area of southeastern California, comparisons with the 1950 survey results, ajid conclusions drawn from this study are summarized in this chapter. Summary This investigation disclosed that in 1958 the following land uses and water requirements existed in the area of investigation: 1. A total of 878,000 acres, or about h percent of all lands within the surveyed aj-ea, had been developed for urban and suburban, and irrigated agriculture uses. This is an increase of about 3^ percent over similar water-using developments that existed in 1950. 2. The estimated mean seasonal level of net water use by these water-using developments was about 3,658,000 acre-feet. This is an increase of about 229,000 acre -feet, or approxi- mately 7 percent, over the I95O estimated net water use level. 3. The gross urban and suburban area was slightly more than 77,000 acres, an increase of about 50,000 acres or l82 percent over that which existed in 1950. This increase was a direct result of an increase in population from 177,000 in 1950 to 350,300 in I960. During the period 1950 to 1958, growth in urban and suburban areas occurred in all hydrographic units witn tne greatest increases taking place in the Antelope Valley and Coachella Valley Units. -71- k. The gross irrigated agricultural area was about 801,000 acres, an increase of about 25 percent over the 642,600 acres that existed in 1950. During the period 1950 to 1958) the greatest growth in irrigated agriculture occurred in the Coachella Valley, Imperial Valley, and Colorado River Units, increasing from about 529,000 acres to about 701,000 acres, or about 32 percent in these units, which are all largely dependent upon diversions from the Colorado Fiiver for their water supplies. 5. In the hydrographic units that are primarily dependent upon local ground water supplies, gross irrigated agriculture decreased from about 101, UOO acres to about 99j700 acres, or about 2 percent, during the period 1950 to 1958. Conclusions Based on the results of this investigation, it is concluded that: 1. Cultural development has occurred and has been sustained in those portions of the desert area of southeastern California where an adequate supply of water is available. 2. Where cultural development in the desert area has been pri- marily dependent on local ground water supplies, irrigated agriculture has decreased as ground water levels have declined with a consequent increase in the cost for water. In the Antelope Valley Unit, for example, the irrigated agricultural development decreased from about 71,000 acres in 1950 to about 57,000 acres in 1958, and declining ground water levels in this unit have increased the cost of pumping -72- to the point \rtiere it is becoming uneconomical to grow certain of the relatively high water-using, low income crops . 3. Where cultural development has been based on imported water supplies, the irrigated agricultural areas have increased. In the portions of the Coachella Valley Unit served with Colorado River water, the irrigated agricultural area in- creased from about 21,000 acres in I95O to about 60,000 acres in 1958, reflecting the availability eind increasing use of Colorado River water which was first imported into this unit in 19'*-9- This increase in the irrigated agri- cultural area that has occurred in this unit since the introduction of Colorado River water, points up the very rapid increases in cultural development that occur in desert areas when an adequate and reasonably economic water supply becomes available. h. The population of the desert area increased about 98 percent during the period I95O to I960, rising from about 177,000 to about 350, 300, and this increase is primarily responsible for the substantial increases in urban eind suburban areas. This type of cultural development does not appear to be as responsive to declining water levels as 'irrigated agricul- ture since urban and suburban areas have continued to increase throughout the desert area, even in those hydro- graphic units where other types of land uses have decreased. -73- 5. The land uses, water requirements, and growth trends estab- lished by this study should be monitored and re-evaluated by future land use surveys in order that the water supplies required to support such growth can be adequately planned and developed. .1 APFEliDIX A DEFDimON OF TER14S A-1 APPENDIX A DEFINITIOH OF TERMS Anni'?^i - The 12-month period from January 1 of a given year through December 31 of "the same year, sometimes termed the "calendar year," Applied Water - Uater delivered to a farmer's headgate, in the case of irrigation use, or to an individual's meter in the case of urban use, or its equivalent. It does not include direct precipitation. Applied Water Requirement - The applied water needed to provide for all beneficial uses and for irrecoverable losses incidental to such uses. It excludes that portion of the requirement which is provided by rainfall. Aquifer - A geologic formation or structure sufficiently permeable to yield an appreciable supply of water to wells or springs. Average - An arithmetical average relating to a period other than a mean period. Confined Ground Water - A body of groimd water immediately overlain by material sufficiently impervious to sever free hydraulic connection with overlying water, and moving under pressure caused by the differ- ence in head between the intake or forebay area and the discharge area of the confined water body. Consumptive Use of V/ater - Water consumed by vegetative growth in tran- spiration and building plant tissue, and water evaporated from adjacent soil, from water surface, and from foliage. It also in- cludes water similarly consumed and evaporated by urban and nonvegetative types of land use. A-2 Free Ground 'fater - A body of grovind water not immediately overlain by impervious materials. Ground V/ater Overdraft - The rate of net extraction of water from a ground ^/ater basin in excess of safe ground water yield. Irrigation Ilfficiency - The ratio of consumptive use of applied irriga- tion ^vater to the total anount of water applied, expressed as a percentage. Mean - An arithmetical average relating to a mean period. Mean Period - A period chosen to represent conditions of \ira.ter supply and clLTate over a long series of years. For purposes of the current investigation, the mean precipitation period embraces the 50 seasons from 1897-98 through 1.9h6-h'J, and the mean runoff period, the 53 seasons from 189^-95 through ISkS-kj. Net ^iater Use - "Net water use" is defined as that portion of the applied water which is consumptively utilized for beneficial purposes or irrecoverably lost. It does not include that portion of the applied ^•rater which is subject to possible reuse. Present - Land use and water supply conditions prevailing during the 1957-58 season. Safe Ground V/ater Yield - The average ann\;ial net amount of water that could be beneficially extracted from a ground water basin over an indefinitely long period of years, under a particular set of those physical conditions affecting supply to, and disposal from, the ground water basin, ^/ithout causing a net lowering of ground water levels during the period. Seasonal - Any 12-month period other than the calendar year. A-3 Vfater Requirement - The vra.ter needed to provide for all 'beneficial uses and for all irrecoverable losses incidental to such uses. Water Utilization - This includes all employments of water by nature or man, whether consumptive or nonconsumptive, as well as irrecoverable losses of vra.ter incidental to such eraployraent, and is synonymous v±t the term "water use," A-k APPENDIX B IRRIGATED AGRICULTURAL LAND USE IN IMPERIAL IRRIGATION DISTRICT IN JUNE, SEPTEMBER, AND DECEMBER I958; AND MARCH 1959 B-1 APPENDIX B IREIGATED AGRICULIURAL LAND USE IN IMPERIAL IRRIGATION DISTRICT IN JUNE, SEPTEMBER, AND DECEMBER I958; AND MARCH 1959 In Acres : June : September . December March Irrigated Agriculture Alfalfa 13»^,380 85,720 135,980 135,860 Pasture 1^,920 7,120 i+,580 2,500 Citrus and subtropical l,h60 1,970 1,830 1,760 Truck crops 12,U60 1U,U10 55,300 2U,790 Field crops 11U,980 65,730 93,170 100, 310 Deciduous fruits and nuts 80 100 100 100 Small grains 16,280 200 Ul,liK) 110,790 Vineyards 80 60 60 80 Subtotals 28lt,6i+0 175,310 332,160 376,190 Pillow 181,080 290, ino 133,560 89, 530 TOTALS 1+65,720 1+65,720 i+65,720 1+65,720 B-2 APPENDIX C LAND USE DJ GROUMD WATER BASIIIS OF THE LAHONTAN AREA OF SOUTHEASTERN CALIFORNIA, I958 C-1 e to (U u o a c 0) >-: O cd a > u u 0) 0) ■ > •H K 3 O (U ^ o > 0) O d ^ > ir\ mo CO OJ J- O CO mo -^1 m O O C\J o ON CO O C oi <£ ^ g U < ^ a W o M 'd > Ci § d w c: eU s « E^ D < S 4) -p d -P o 0) d Sh rd d o a) -d H CJ d ON CM OJ O Id d cd I to 'd d td d (d •s o o oooooooo o o oooooooo oooooooo o o oooooooo oooooooo! o •H < -d o •H 0) o ^ o EH frt o en > cd ■p o -p CO o o o o cd (0 c: (!) a Pi ij (U o > OJ O VO O OJ CM rOOJ H o 0\ CO CD ro CM H o H ^ .-I d ■H •P C (U -d •H H ^.3 5 a) M -P I a 'd c a d 0) H C!j -H 4J u d w o J 00 UTN fO VO CO ON CO LP\ -4- , rH 01 o rH ^ cd > o o cd 5 >i > (U cd rH ^ d > f. •^ > d >J £: O (U rH e rH o i) ^ >1 0) u rH fl rH (U td a > td o (d a >. o 0) N H td ^ o > r-l o >> -p Cl to rH ■H -5 m > o bO >5 (U to :3 ■d § H Ch O to to td rH o tS a cd to -d c p o -p O o O l/N CO rH cd Sh (U CO I u 1:1 1 O CJN NO O LfN ITN as o o r-t en L'N O OJ NO CO O rH CO c^ +> ■ o • •H !h I ^1 Tf 1 tt) I H-> ! cd bO( •H I !-i E U • M : W CO to CO o o ^1 « o o D-2 P< a) ? > 2 rH ^ i> w >> HI C .-I O rH -P Ct! 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