LIBRARY UNIVERSITY OF CALIFORNIA DAVIS 1U^ Lib f •' il THE RESOURCES AGENCY OF CALIFORNIA Department of Wa ter Resources BULLETIN No. 102 SAN DIEGO COUNTY LAND AND WATER USE SURVEY 1958 HUGO FISHER Adm'inistraior The Resources Agency of California AUGUST 1963 EDMUND G. BROWN Governor State of California WILLIAM E. WARNE Director Department of Water Resources state of California THE RESOURCES AGENCY OF CALIFORNIA Department of Water Resources BULLETIN No. 102 SAN DIEGO COUNTY .AND AND WATER USE SURVEY, 1958 AUGUST 1963 HUGO FISHER Administrator The Resources Agency of California EDMUND G. BROWN Governor State of California WILLIAM E. WARNE Direcfor Department of Water Resources TABLE OF CONTENTS LETTER OF TRANSMITTAL ACKNOWLEDGMENT ORGANIZATION CHAPTER I. INTRODUCTION Authorization Scope of Investigation and Report Related Investigations and Reports CHAPTER II. AREA OF INVESTIGATION Location and Description Hydrographic Units Agricultural Development Urban and Suburban Development Water Supply Local Water Supply Imported Supply Waste Water Disposal CHAPTER III. LAND USE Methods and Procedures Classification of Land Use Results of Land Use Survey Recent Changes in Land Use Santa Margarita-San Luis Rey Unit (9-8) Page vii viii ix 2 3 5 7 9 10 13 17 17 19 21 25 26 30 35 36 111 Page San Dieguito-Cottonwood Unit (9-9) 36 San Diego Unit (9-10) 36 Salton Sea Unit (7-3) 36 Multiple Cropped Areas 37 CHAPTER IV. WATER USE Definition of Water Use kl Methods of Estimating Water Use k2 Unit Values of Water Use h^ Urban Water Use Values hk Unit Values of Water on Irrigated Agriculture ^5 Net Water Use ^6 Comparison of Water Supply and Water Use ^9 CHAPTER V. SUMMARY" AND CONCLUSIONS Summary 53 Conclusions ^k TABLES Table No . Page 1 Areas of Hydrographic Units in San Diego County and a Portion of Southwestern Riverside County 10 2 Historical Seasonal Deliveries of Imported Colorado River Water to San Diego County by The Metropolitan Water District of Southern California 20 3 Factors for Reduction of Gross Areas to Net Water Service Areas 29 iv TABLES Table No. Page k Land Use in Hydrographic Units of San Diego County and a Portion of Southwestern (Facing) Riverside County in 1958 30 5 Land Use in San Diego County and a Portion of Southwestern Riverside County in 1958 31 6 Land Use in Member Agencies of the San Diego (Facing) County Water Authority in 1958 32 7 Land Use in Coastal San Diego County and Southwestern Riverside County in 19^8 and 1958 and in the Desert Portion of (Facing) San Diego County in I95O and I958 36 8 Disposition of Acreage Found Fallow in Summer 1958 39 9 Estimated Mean Seasonal Unit Values of Consumptive Use of Water on Urban and Suburban Lands in San Diego County ^^ 10 Estimated Mean Seasonal Unit Values of Water Delivery to Urban and Suburban Lands, San Diego Hydrographic Unit ^5 11 Estimated Mean Seasonal Unit Values of Consumptive Use of Water on Irrigated (Facing) Lands in San Diego County ^o 12 Estimated Levels of Net Water Use in San Diego County and a Portion of Southwestern Riverside County for Conditions of Development in 191^8 and 1958 k3 13 Comparison of Net Water Use and Water Supply of Coastal San Diego County and a Portion, of Southwestern Riverside County ^9 FIGURES Figure No . 1 Historical Use of Land for Irrigated Agriculture in San Diego County, I888 to 1958 Population of San Diego County, i860 to i960 . . 13 16 ILLUSTRATIONS Page San Diego Frontispiece Irrigated Lands in San Diego County 11 Urban Grovth Along the Coast ill- Urban Development and Irrigated Agriculture in the Escondido Area 2k- Urban Ejqpansion in San Diego, 1950 to 1957 31*- PLATES Plate No . 1 Area of Investigation 2 Major Water Agencies and Hydrographic Units 3 Ground Water Basins and Hydrologic Units and Subunits k Present Land Use 5 Change in Land Use, I9U8 to I958 APPENDIXES Appendix A Definition of Terms B Land Use in Hydrologic Units and Subunits in San Diego County BJid a Portion of Southwestern Riverside County in 1958 C List of Districts, Areas, and Units for Which Individual Tabulations of 1958 Land Uses are Available VI EDMUND G. BROWN HUGO FISHER M E. WARNE GOVERNOR OF ADMINISTRATOR ADDRESS REPLY TO r.c.c,of CALIFORNIA RESOURCES AGENCY P. O. Box 388 r Rejources >(S^S^i4. Socramenlo 2, Calif. }n GOLDBERG •puty Director VLD C. PRICE Director Policy t GARDNER ty Director inistrotion „.^„, . THE RESOURCES AGENCY OF CALIFORNIA D R. GOLZE """'""' DEPARTMENT OF WATER RESOURCES 1120 N STREET, SACRAMENTO June 6, 1963 Honorable Edmund G. Brovm, Governor, and Members of the Legislature of the State of California State Capitol Sacramento, California Gentlemen: I am pleased to transmit herewith Department of Water Resources Bulletin No. 102, "San Diego County Land and Water Use Survey, 1958/' which was prepared as a part of the department's continuing program of studies of the use of the water resources of the State, pursuant to Sections 225, 226, and 232 of the Water Code. This type of information is basic to sound planning for future water development. All of San Diego County, and a portion of southwestern Riverside County were surveyed during the investigation; data on land use and estimates of water use for 1958 are presented in the report. Changes in land and water use since 19^, the year of the previous survey, are also evaluated . During the 10 -year period between 19^ and 1958, there was an increase of about h6 percent in the gross water service area, and the net water use in the area of investigation increased about 3^ percent to approximately 2ii-9,200 acre-feet per season. It is predicted that with the full development of habitable lands within the coastal portion of this area, net water use will increase about 400 percent, to a total of 1,117,000 acre-feet, or about 993,000 acre-feet in excess of the safe yield of local water resources. The ever increasing need for water in San Diego County and in other areas of Southern California, coupled with the already deficient local water supplies, points up the urgent need for the importation of additional water to this area. Sincerely yours. i^y-..^ f^ ^^""-^ Director vii ACiaJOWLEDGMEl^ Valuable assistance and data for this investigation and report were contributed by public and private agencies. Special mention is made of the cooperation received from the City of San Diego. The cooperation and assistance received is gratefully aclcnowledged. viii STATE OF CALIFORNIA THE RESCURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES EDMUND G. BROWN, Governor HUGO FISHER, Administrator, The Resources Agency of California WILLIAM E. WARNE, Director, Department of Water Resources ALFRED R. GOLZE ' , Chief Engineer JOHN R. TEERUK, Assistant Chief Engineer SOUTHERN DISTRICT James J. Doody District Engineer Herbert W. Greydanus 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 Ronald G. Hansen Senior Engineer Elvood C. Johnson Water Resources Engineering Associate assisted by Barry P. Brown Assistant Land and Water Use Analyst Robert D. Smith Assistant Land and Water Use Analyst Evangeline Schulten Engineering Aide I Sumi Minatoya Delineator Ix CHAPTER I. INTRODUCTION The story of California's spectacular and unprecedented growth has "been typified during the past several decades by the rapid develop- ment experienced in San Diego County. San Diego, an area of productive lands and a mild, equable climate has become one of the fastest growing areas in the nation. Large numbers of people have been attracted by the climate and, certain industries, among which aircraft manufacturing is predominant, have located in the area to take advantage of the labor force. In addition, the long frost-free periods have been found highly favorable for production of certain valuable subtropical fruits and other specialty crops. Development in San Diego County has greatly depended upon the availability of water supplies, and during the past several years, local water storage reserves have been virtually depleted, making large portions of the county almost fully dependent on imported Colorado River water. This report presents information on the rate of urban and agri- cultural development and the increasing needs of this cultural develop- ment 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 San Diego County and a portion of southwestern Riverside County during the summer of 1958- Land use information is gathered to obtain basic data from which present water use can be computed and future requirements can be forecast. Knowledge of current patterns 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 unit water requirements, pro- vides a basis upon which future water requirements can be determined and upon which 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 effective use of existing water supplies and in developing additional supplies to meet current and expected deficiencies. Authorization The California Legislature of 1929 enacted legislation, pro- viding for investigations of this kind, as follows: "SECTION 1. Out of any money in the state treasury not otherwise appropriated, the sum of four hundred fifty thousand dollars*, or so much thereof as may be necessary, is hereby appropriated to be expended by the state department of public works in accordance with law in conducting work of exploration, investigation and preliminary plans in furtherance of a coordinated plan for the conservation, development and utiliza- tion of the water resources of California including the Santa Ana river and its tributaries, the Mojave river and its tributaries, and all other water resources of southern California." (California Statutes of 1929, Chapter 832, Section l) ♦Reduced by the Governor to $390,000. Subsequent sessions of the Legislature have appropriated funds for support of programs of the Department of Water Resources. Portions of these funds have been utilized for continuing investigations of the water resources of Southern California in accordance with the legislative intent expressed in the foregoing statute and in Sections 225 and 226 of the State V/ater Code. In 1956, the Legislature further directed the Department of Water Resources to make continuing investigations to develop "informa- tion as 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 specif icaJ.ly requested investigation of and reports on 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; (d) The areas which can be served by the water available for export from each watershed; and (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 judgment of the Director of Water Resources, are insufficient in the aggregate to materially affect the qusmtitative determi- nations included in the report." (Calif, Stats. 1956 (Ex, Sess,), ch, 6lj Water Code Section 232). Pursuant to the foregoing legislative directives, the Department of Water Resources began a program of continuing surveys of land and water use in the Southern California area during 1957* Surveys are programmed to be made in one of five portions of the whole area each year on a continuing basis so that land and water use data are deter- mined at regular intervaJLs. Scope of Investigation and Report This report contains the results of a comprehensive survey of the nature and extent of land and water use within San Diego County and a portion of southwestern Riverside County. The area of investigation is shown on Plate 1, "Area of Investigation." Present land use was determined from an assimilation of two field surveys. The Department of Water Resources surveyed most of the investigational area during the summer of 1958« The Planning Department of the City of San Diego inventoried all commercially and industrially zoned areas within its boundaries during 1958> and the results of the City's survey were integrated with the data obtained by the department. In addition to showing present land use, this report presents estimates of present water use. Data obtained from the land use survey conducted in connection with the preparation of State Water Resources Board Bulletin No. 2, "Water Utilization and Requirements of California," were utilized as the basis for comparison between 19^+8 and 1958 land and water use patterns. Data on local water supplies, importations of water from outside sources, and sewage exports were developed from material in the department's files and from information obtained from operating agencies in the area of investigation. Terms used in this report, which require clarification, are defined at the point where they first occur in the text, aind are supple- mented by a list of definitions, presented in Appendix A. Land use information collected by the Department of Water Resources is processed by machine techniques which permit the evaluation of this data in terms of a sizable number of hydrologic, geographic, or political subdivisions -vrith different boundaries. The tabulations in the main body of this report give land use within the boundaries which are thought to be the most generally useful. Additional lajid use tabulations for hydrologic units and subunits are given in Appendix B, and Appendix C contains a list of districts, areas, and units for which individual tabulations of 1958 land uses can be obtained by machine methods, based on data available in the department's files. Related Investigations and Reports The California Legislature in 1947 amended the Water Resources Law of 1945 to authorize the Water Resources Board, a predecessor of the Department of Water Resources, to conduct a comprehensive investigation of water resources throughout the State of California (Calif. Stats. 1945, ch. 1514, p. 2830; as amended by Calif. Stats. 1947, ch. 908; Water Code Section 12616). The investigation had as its purpose the preparation of the California Water Plan. Results of the investigation are contained in three publications: California State Water Resources Board Biilletin No. 1, "Water Resources of California," 1951; California State Water Resources Board Bulletin No. 2, "Water Utilization and Requirements of CaLifornia," June 1955; and California State 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 1948 and determination of water utilization in San Diego County for conditions of 1948, The following reports contain information pertinent to land and water use within the investigational area; California State Department of Public V/orks, Division of Water Resources. "San Diego County Investigation." Bulletin No. 48. 1935. . "Santa Margarita River Investigation." Bulletin No. 57. June 1956. California State Department of Water Resources. "San Dieguito River Investigation." Bulletin No. 72. November 1959. "Investigation of Alternative Aqueduct Routes to San Diego County." Bulletin No. 6l. 1957- "Investigation of Alternative Aqueduct Systems to Serve Southern California." Bulletin No. 78. December 1959. Stanbery, Van Buren. "Population Analysis and Projections, I96O and 1970, County and City of San Diego." CHAPTER II. AREA OF INVESTIGATION The area under investigation embraces a total of approximately i+, 880 square miles and is located in the southwesterly corner of California. The general location of the area is shown on Plate 1, and in greater detail on Plate 2, "Major Water Agencies and Hydrographic Units." Location and Description The investigational area includes all of San Diego County and the portion of southwestern Riverside County which is drained by tribu- taries of the Santa Margarita River, San Luis Rey River and San Mateo Creek. The area is bounded on the south by the international boundary line between the United States and Mexico and by the Pacific Ocean on the west. Orange County bounds the area on the northwest and relatively low- lying drainage divides form the northern boundary in Riverside County. These divides separate the area from the adjacent watershed of the Santa Ana River. Imperial County lies to the east. Topographically, San Diego County can be divided into two distinct zones: coastal and desert. The coastal zone lies on the western side of the Peninsular Range, which forms the main divide and crosses the county in a southeasterly direction. The coastal segment, which is characterized by rolling hills and mesa lands, includes approximately two-thirds of the area of investigation. The eastern portion or desert area coinprises the remaining one-third of the area, and consists of about equal parts of valley and mesa lands. The climate of San Diego County varies considerably with distance from the ocean, elevation, and topography. The coastal region enjoys a mild, equable, Mediterranean-type climate, with cool, moist winters and dry summers. Temperatures rarely deviate more than 15 degrees from the annual mean of 71 degrees Fahrenheit, either from day to night, or from winter to summer. The mean seasonal precipitation is approximately 10 inches near the coast and occurs principally in the winter months. Proceeding inland, as elevations increase, temperature varia- tions become wider ajtid precipitation becomes heavier. At the highest inland elevation of the tributary watershed, average seasonal rainfall is in excess of k-0 inches. The climate of the eastern or desert portion of San Diego County is characterized by short, mild winters and exceptionally hot summers, with low humidity and scant rainfall. Average seasonaJ. precipitation is only about 3*5 inches and the greater portion frequently results from localized thunderstorms. The principal streams draining the coastal section of the area include the Santa Margarita, San Luis Rey, San Dieguito, San Diego, Sweetwater, Otay, and Tia Juana Rivers. The Santa Margarita p{iver is formed by Temecula and Murrieta Creeks and begins at the junction of these creeks near the town of Temecula. From this point it flows about 27 miles in a southwesterly direction to a point three miles northwest of Oceanside where it discharges into the Pacific Ocean. The San Luis Rey River, draining the Aqua Tibia or Palomar Mountains, and the San Dieguito River, known as Santa Ysabel Creek from its source on the west slope of Volcan Mountain to the San Pasqual Valley, are two other main streams draining the northwestern portion of the area. Principal tributaries to the Ssui Dieguito River are Black 8 Canyon, Temescal, Santa Maria and Guijito Creeks. The San Diego River, the principal stream draining the southern portion of San Diego County, rises near Julian and flows in a southwesterly direction to discharge into the Pacific Ocean. The main tributaries include Cedar, Boulder, Chocolate, Small Fork, Las Coches, and San Vicente Creeks. The Tia Juana River comprises that part of the main stream helow Rodriguez Dam in Mexico, and is about 17 miles long. It flows in a general northwesterly direction, entering the United States from Mexico near the town of San Ysidro. From thence, it drains into the Pacific Ocean about two miles north of the international boundary line. Cottonwood Creek, the principal tributary of the Tia Juana River, rises on the slopes of Laguna Mountain and drains practically all of that part of the basin lying in the United States. It flows in a general southwesterly direction to about four miles below the international boundary line where it joins the main Tia Jueina River. Other streams in San Diego County include the Sweetwater River which drains the Cuyamaca Mountains, and the Otay River draining the San Ysidro Mountains. The runoff in these streams is subject to wide varia- tions from season to season and, because of the nature of its origin in precipitation, occurs almost entirely during the months from November through April. Hydrographic Units To aid in hydrologic analysis, the investigational area was subdivided into six hydrographic units, as delineated on Plate 2. For purposes of comparison, these units correspond to those used in State Water Resources Board Bulletin No. 2, "Water Utilization and Requirements of CeLLifomia, " except that this investigation covered only the portion of the San Juan Capistrano Unit (9-7) lying southerly of the Orange County line, and those portions of Coachella Valley Unit (7-2) and Salton Sea Unit (7-3) which are within San Diego County. The boundaries of the hydrographic units generally follow topographic divides, with the exceptions noted, but boundaries of San Diego Hydrographic Unit (9-10), also termed the San Diego Metropolitem Area, were selected on the basis of the probable ultimate limits of intensive urbanization. Table 1 lists the six hydrographic units and their areas within the area of investigation. TABIE 1 AREAS OF HYDROGRAPHIC UNITS IN SAN DIEGO COUNTY AND A PORTION OF SOUTHWESTERN RIVERSIDE COUNTY Hydrographic unit . Acres San Juan Capistrano Santa Margarita- San Luis Rey San Dieguito-Cottonwood San Diego Coachella Valley Salton Sea TOTAL Agricultural Development The first known agricultural development in San Diego County came with the founding of San Diego Mission by the Franciscan Fathers in 1769. Water from the Ssui Diego River, originally obtained by sui-face diversion and later supplemented by wells dug in the river, was used to 10 (9-7) 118, 500 (9-8) 870, 500 (9-9) 988,300 (9-10) 333, 300 (7-2) 20,500 (7-3) 790,100 3,121,200 irrigate fields surrounding the Mission. Similar agricultural develop- ment accompanied the establishment of the Mission San Luis Rey. It was not until the latter half of the 19th century that significant expansion of irrigation began. This development was brought about mainly by completion of the first railroad in I885 and the result- ing real estate boom. However, until the completion of the Sweetwater and Cuyamaca water systems, irrigation was confined to the small and scattered areas in the various stream basins. The irrigated acreage increased steadily as additional surface water storage and diversion facilities were constructed, and as ground water supplies were utilized. Winter truck crops were first produced comraercisLlly near San Diego about I9IO, and in I915, avocados and other subtropical fruit were introduced to the area. The mild climate with long frost -free periods was found highly favorable for production of these crops and was, there- fore, influential in stimulating an intensive agricultural development in areas where water was available. The growth of irrigated agriculture in San Diego County, based on surveys made in I888, 1912, 1926, 1932, 19^8, as well as 1958, is shown on Figure 1. The amount of irrigated agriculture increased over 10 times between I888 and 1912, and 133 percent between I912 and 1926. These were the periods in which increasing amounts of water were developed for irrigation purposes. Increases in irrigated agriculture acreage between 1926 and 1932 were minor, but following that period lands were broi;ight into production at an increasing rate. The pattern of agricultural land use has remained fairly stable during the past half century, with avocados, citrus, and truck crops 12 t/5 llJ uj a: o o < < UJ (T U. o o < a <=> UJ z h- < := O eo 60 20 c (D ^ 03 ov CM '2 ff» (J) YEAR HISTORICAL USE OF LAND FOR IRRIGATED AGRICULTURE IN SAN DIEGO COUNTY FIGURE I continuing as the principal produce of the area. Although there has been a recent increase in the amount of acreage devoted to irrigated pasture, this use continues to be of lesser importance. Urban and Suburban Development In the past severaJ. years, San Diego has become one of the most rapidly developing urban areas in the nation. Although the total vrater service area is presently almost equally divided between irrigated agri- cultural and urban- suburban lands, the county is fast becoming a predominantly urban- suburban area. 13 During the period between 19^ and 1958> the increase in urban- suburban lands was 7^ percent, or about 3 times as great as the percentage increase experienced in irrigated agricxilture. This tremendous growth of \irban- suburban lands is most apparent in the densely populated San Diego metropolitan area and the less populous but rapidly growing communities of Escondido, Oceanside, Carlsbad, Fallbrook, and Rainbow. This urbanization has largely taken place on agricultiireil lands immediately adjacent to existing urbem areas, although the loss of agricultural land has been more than offset by expansion of agri- culture on formerly xindeveloped lands. Major industries in the area are aircraft manufacturing and fishing. In addition, the headquarters of the 11th Naval District, including training, repair, air, supply, and radio facilities are located in the San Diego metropolitan area. Camp Pendleton, the largest Marine Corps base in the nation, is located near Oceemside. The population of San Diego County grew slowly until the latter part of the 19th century being in large part limited by lack of firm water supplies and adequate transportation facilities. After the turn of the century, however, with the initiation of several water development projects and the completion of the first railroad, the area's population began a generally steady but accelerated growth. This growth is shovra graphically on Figure 2. During the first half of the century, San Diego experienced a more rapid groTrth in population than either the State or nation. As 15 YEAR POPULATION IN SAN DIEGO COUNTY, I860 TO I960 FIGURE 2 shown on Figure 2, the population of San Diego County increased to 1» 033, 000 in i960. Some 573,200 persons resided within the San Diego City limits in I96O. The investigational area also includes a portion of south- western Riverside Covinty but population data for this area were not available for 1950. However, from the I96O U. S. Bureau of the Census Report, it was determined that about 2,500 persons resided in the Riverside portion of the investigational area. The total population of the investigational area was about 1,035>500 in 19^0. 16 Water Supply Water supplies for the urban and agricultural developments in the coastal portion of the investigational area have historically been derived from surface storage developments and, to a lesser extent, by pumping from ground water storage. In recent years, increasing amounts of water imported from the Colorado River through the San Diego aqueduct have been utilized. The limited development in the desert areas is almost solely dependent on ground water extractions. Local Water Supply Historical development of local water supplies in the coastal portion of the investigational area was begun in connection with the San Diego missions in the early part of the nineteenth century, however, rapid growth did not begin until I888, following construction of the surface water supply developments on the Sweetwater River and on Boulder Creek, a tributary of the San Diego River. Since that time, major sur- face water storage and diversion developments have been constructed on all of the principal streams in the investigational area, with the excep- tion of the Santa Margarita River. The combined storage capacity of the surface reservoirs is about 736,800 acre-feet. Studies conducted in connection with the preparation of Department of Water Resources Bulletin No. 61, "Investigation of Alternative Aqueduct Routes to San Diego County," indicate that these reservoirs have a nominal sai"e yield of about 66,000 acre-feet per season. Subsequent to the availability of Colorado River water, it has become the practice of the City of San Diego to operate their reservoirs 17 on a maximum yield basis. Under this type of operation winter runoff stored in the reservoirs is released for use as rapidly as possible in an endeavor to reduce evaporation losses and thus increase efficiency of use. This method of operation also provides greater storage capacity for conservation during the infrequent years of high runoff, so that waste to the ocean is reduced. However, this method of operation requires greater dependence on imported water supplies during drought periods. Local water developments based on extractions from water-bearing formations have played a less significant role in urban and agricultural development of coastal Saxi Diego County than in most other areas of Southern California. In general, ground water extractions have been limited to the recent alluvium, as older formations usually have a low yield and often contain water of poor quality. For the most part, the recent alluvial deposits are of limited extent and storage capacity, so that conservation of water supplies and cyclic regulation of erratic stream flows by ground water storage is limited. The areal extent of the ground water basins is delineated on Plate 3^ "Ground Water Basins and Hydrologic Units and Subunits." Studies made in connection with the preparation of Division of Water Resources Bulletin No. kd, "San Diego County Investigation, " published in 1935 indicate that the safe local yield (the yield assuming no imported supplies are available) of the ground water basins in the coastal portions of the area of investigation, including southwestern Riverside County, is on the order of 58,000 acre-feet. The safe yield of the ground water basins in the desert portion of San Diego County is not known. However, in the preparation of 18 Bulletin No. 2, it was assumed that this yield was approximately equal to the requirements in 1950^ or about 10,000 acre-feet, and this value is also adopted for use herein. The total safe local yield in the area of investigation is therefore equal to approximately 13^,000 acre-feet, comprising 66,000 acre-feet of surface water and 68,000 acre-feet of ground water. These estimates of local water supplies reflect mean hydrologic conditions for the period from 188? to 1933 for the Bulletin No. k8 study, and 1887-88 to 19^8-49 for the Bulletin No. 6l study. These derived values do not reflect the possible lowering effect of the extended period of below- normal rainfall vrtiich has continued in the investigated area for several years. Imported Supply Water is imported to coastal San Diego County through the facilities of the Colorado River Aqueduct of The Metropolitan Water District of Southern California and the First and Second San Diego Aque- ducts. Table 2 presents the seasonal deliveries of imported Colorado River water to San Diego County. The First San Diego Aqueduct was constructed with two barrels of approximately equal capacity totaling about 200 second-feet. The first barrel was constructed by the United States Navy and completed in 19^+7 as an emergency measure to provide water supplies made necessary by expansion of military and industrial installations and the attendant population increases resulting from World War II. The second barrel of the aqueduct was constructed by the U. S. Bureau of Reclamation and i9 TABLE 2 HISTORICAL SEASONAL DELIVERIES OF IMPORTED COLORADO RIVER WATER TO SAN DIEGO COUNTY BY THE METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA In acre -feet Season ending Total September 30 delivered I9U7-I+8 59,000 1948-1+9 70,900 19^^9-50 70, 300 1950-51 75,100 1951-52 1+5,100 1952-53 U5,300 1953-5^^ 72,800 195^-55 m , 500 1955-56 11+2,100 1956-57 ii+i+,Uoo 1957-58 135,600 1958-59 110,600 completed in 195^ • Ownership and operation of the aqueduct were assumed by the San Diego County Water Authority by contract with the United States which provides for repayment of the construction costs by the former agency with partial assistance by The Nfetropolitan Water District of Southern California. Shortly after completion of the First San Diego Aqueduct, it became apparent that additional imported water would soon be required to supply the needs of the San Diego County Water Authority. The Metropolitan Water District of Southern California constructed the north- em portion of the Second San Diego Aqueduct to a point six miles southerly of the Riverside-San Diego County line, and the Ssui Diego 20 County Water Authority constructed the remaining portion in San Diego County, completing work in I960. The Second Aqueduct lies generally parallel to and approximately six miles westerly of the First San Diego Aqueduct. The portion constructed by the San Diego County Water Authority has an initial capacity of about 250 second-feet. The com- pleted First San Diego Aqueduct and the presently completed stage of the Second San Diego Aqueduct provide a combined capacity of U50 second-feet. Waste Water Disposal. The waste water effluents within the investigational area are discharged to the Pacific Ocean or nearby tidal lagoons; discharged to stream channels, where effluent either percolates to underlying ground water basins, or is pumped directly for irrigation purposes; or are disposed of in cesspools or septic tanks. In addition, some discharges which would otherwise be lost to the ocean are reclaimed for reuse. For purposes of this investigation, it was assumed that waste water effluents discharged to the ocean or tidal lagoons were irrecoverably lost but that £ill other effluents were available for reuse. In 1958 discharges to the ocean were made from a number of cities and communities in the area of investigation including San Diego, Chula Vista, Carlsbad, Imperial Beach, Palm City, Coronado, Del Mar, Cardiff, Solana Beach, and San Ysidro which discharges to the Inter- national Outfall Sewer. Available records of discharge to the ocean from these plants vary in length, and in a number of cases consist only of estimated flows. Based upon available data it was estimated that discharges to the ocean or its tidal waters during the 1957-58 water 21 year, totaled about 59,000 acre-feet. Estimates for the 1950-51 vater jrear indicate the discharges to the ocean were on the order of 38,000 acre -feet. An indication of problems of water shortage in San Diego County may be seen from the efforts which have recently been made to reclaim water from sewage formerly discharged to the ocean. This sewage was reclaimed for replenishment of ground water and for direct irriga- tion. Examples of reclamation projects include that of the City of Oceanside, which began reclaiming water for ground water replenishment and irrigation in 1958, and the Encinitas Sanitary District which began selling effluent for the irrigation of flowers in 1958. 22 • •- • * mm ■.'.' i ^ :JrM ,r^'.' ?4' Mm y \\ Ji^? ir -^ •- *v.i -1, ■■£■ 'fli ii-*S^ ;^i V'r J^' s:: i"^-" i^^ » « (>-:, k>. •vim 1 .i5?. ,J r^ 3 V, f 14 ^\ :>*..^3 *:^ ■I • CHAPTER III. lAND USE The type, location, and areal extent of land use within the study- area vere determined by a compilation of data from a survey conducted by the Department of Water Resources during the summer of 1958^ an it should be noted that all land use requiring applied water in the San Juan Capistrano Unit is within a military reservation, and in accordance with the Ismd use definitions used herein is placed in the "Unclassified" category. Detailed information concerning the pattern of land use as deter- mined from this survey may be found on Plates kk and ij-B. Although the acreages of nonwater service areas within urban and suburban and irrigated agricultural areas are shown separately on the summary tables, they were not differentiated on the plates. Also, not differentiated on these plates were developed nonwater service lands, such as nonirrigated agriculture, and vmdeveloped nonwater service lands, such as native vegetation. A determination of the amount and location of lands considered susceptible of intensive water-using development in coastal San Diego County and southwestern Riverside County was made in connection with the 30 TABLE h LAND USE IN HYDROGRAPHIC UNITS OF SAN DIEGO COUNTY AND A PORTION OF SOUTHWESTERN RIVERSIDE COUNTY IN I958 In Acres Category and Class of Land Use Coastal Hydrographlc Unit : Santa San Juan : Margarita- Capl8trano*:San Luis Rey (9-7) = (^8) San Dleguito- Cottonwood (9- 9) San Diego (9-10) Desert Coachella : Valley : (T-2) = Salton Sea (T-3 ) Totals WATER SERVICE AREA Urbaji and Suburban Residential CoranerciaJ. Industrial Unsegregated urban and suburban area Subtotals Included Nonwater Service Area Gross Urban and Suburban Area Irrigated Agriculture Alfalfa Pasture Citrus and 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 NONWATER SERVICE AREA Nonlrrigated Agriculture Native Vegetation Unclassified GROSS NONWATER SERVICE AREA TOTALS ♦All land use requiring applied water is within a military reservation, and appears in the category "unclassified" . 2,900 380 70 1.990 5,020 550 70 2.830 32,920 2,780 81+0 i+,i6o 280 30 10 _20 1+1,120 3,71+0 990 9,070 5,3'+0 8,1+70 1+0,700 1+10 5l+,920 2,170 3.310 29.530 1+90 35,?oo 7,510 11,780 70,230 900 90,1*20 2,1+20 '^,320 13,2UO 5,680 860 860 1,1*20 170 1,010 3,560 13,320 1,21+0 50 960 3,500 ?50 1,100 1,950 5,220 5,750 1+60 ll+O 890 1+0 1,610 1+70 90 1+20 380 60 580 1,990 6,11+0 10,300 31,870 13,090 1,750 2,020 6,390 2.750 28,970 2l+,190 15,550 5,600 7"+, 310 1,360 2,160 960 2,180 U,260 2,650 70 1,390 6,650 8,380 32,1+90 27,330 22,1+60 7,060 89,31*0 Uo.ooo 39,110 92,690 7,960 179,760 118,520 99,860 117, 2U0 613,1+20 1+8,190 35,81+0 865,120 6,21+0 21,510 212,800 8,510 12,010 2,280 30l+,96o 1+71+ , 900 156,570 1+88,060 2,296,770 118,520 830,520 9^9.150 21+0,550 20,520 782,11+0 2,91+1,1+00 118,520 870,520 988,260 333,21+0 20,520 790,100 3,121,160 TABLE 5 LAND USE IN SAN DIEGO COUNTY AND A PORTION OF SOUTHWESTERN RIVERSIDE COUNTY IN I958 In Acres Category and Class of Lajid Use : Riverside :San Diego; : County ; County : Totals WATER SERVICE AREA Urban and Suburban Residential Commercial Industrial Unsegregated urban and suburban area Subtotals Included Nonwater Service Area Gross Urban and Suburban Area Irrigated Agriculture Alfalfa Pasture Citrus and 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 NONWATER SERVICE AREA Nonirrigated Agriculture Native Vegetation Unclassified GROSS NOm/ATER SERVICE AREA TOTALS 160 70 720 i+0,960 3,670 990 8,350 i+1,120 3,7^0 990 9,070 950 53,970 5^^,920 220 35,280 3?, 500 1,170 89,250 90,U20 1,8U0 1,300 300 1,2U0 3i^o 160 U,300 9,000 31,570 11,850 1,U10 1,860 6,lhO 10,300 31,870 13,090 1,750 2,020 100 6,290 2,750 69,030 6,390 2,750 5,280 7i+,310 550 Uoo 6,100 7,980 6,650 8,380 6,230 83,110 89,3^+0 7,U00 172,360 179,760 68, hko 86,220 2UU,190 88,130 Uoi,8Uo 2,052,580 156,570 U88,o6o 2,296,770 398,850 2,5^+2.550 2,9^+1,^00 i^06,250 2,7lU,910 3,121,160 *Less than 5 acres. prepsLration of Department of Water Resovirces Bulletin No. 78, "Investiga- tion of Alternative Aqueduct Systems to Serve Southern California." In that report the estimated gross urbein and suburban acreage in the year 2020, in cOcLStal San Diego County and the portion of Riverside County vithin the area of this investigation, in I^rdrographic Units 7, 8, 9 and 10, was 352,000 acres. The gross urban and suburban water service area determined from the 1958 survey in these Hydrographic Units occupies 89,500 acres, or 25 percent of the forecast area. The estimated net irrigated acreage for the year 2020 was forecast to be 178,000 acres. This compares to a net acreage of 68,700 acres in 1958 or 39 percent of the forecast value. The results of another study conducted in the desert portion of San Diego County in Hydrographic Unit 3> in connection with the preparation of Bulletin No. 2, indicated 78,800 gross acres susceptible of intensive water-using develop- ment under ultimate conditions, which compares with the present gross water service sirea of about 8,000 acres, or 10 percent of the total susceptible of development. A tabulation of land use as observed within the boundairies of the water agencies which are constituent members of the San Diego County Water Authority is presented in Table 6. This table shows that about 489,300 acres are included within the boundaries of the San Diego County Water Authority, which is a member agency of The Metropolitan Water District of Southern California. Of this total, about 13'4-,700 acres, or 28 percent of the area, are devoted to land uses requiring water service. ISiis water service area represents 78 percent of the toteuL water service so^ea in San Diego County, and 75 percent of the total for the entire investigational area. 32 I iblo pal r Let Rio San Diego Municipal Water District Valley Center Municipal Water District Fallbrook Public Utility District Total 30 ro 10 10 LO )0 LO ro lo ro ro )0 ^0 jo 50 .0 610 60 10 i+00 1,080 320 1,600 50 ihO 570 260 30 190 30 1,870 170 120 50 20 I 320 390 70 i^6o U,220 290 UliO 630 30 10 ko 710 2hO 950 70 1,210 790 U,210 220 50 10 520 1,220 180 U,26o 220 37,670 3,200 9I+O 5,650 k'j,h6o 31,500 78,960 650 4,230 27,5^0 9,lUo 220 1,230 2,250 700 i+5,960 U,790 5.030 io 2,160 U,950 U,U80 55,780 ^0 3,760 5,U10 5,^30 13^,7^+0 \0 1,0U0 1,380 31,160 to 2,860 1,580 70 36,210 jO 12,370 U6,88o 2,650 287,210 LO 16,270 U9,8U0 2,720 351+, 580 50 20,030 55,250 8,150 1+89,320 prepsuration of Depeirtnient of Water Resources Bulletin No. 78^ "Investiga- tion of Alternative Aqueduct Systems to Serve Southern California." In that report the estimated gross urbsua eind suburban acreage in the year 2020, in coastal San Diego County and the portion of Riverside Coxinty within the area of this investigation, in Hydrographic Units 7, 8, 9 and 10, was 352,000 acres. The gross urban and suburban water service area determined from the 1958 survey in these Hydrographic Units occupies 89,500 acres, or 25 percent of the forecast area. The estimated net irrigated acreage for the year 2020 was forecast to be 178,000 acres. This compsures to a net acreage of 68,700 acres in 1958 or 39 percent of the forecast value. The results of another study conducted in the desert portion of San Diego County in Hydrographic Unit 3, in connection with the preparation of Bulletin No. 2, indicated 78,800 gross acres susceptible of intensive water-using develop- ment under ultimate conditions, which compares with the present gross water service area of about 8,000 acres, or 10 percent of the total susceptible of development. A tabulation of land use as observed within the boundaries of the water agencies which are constituent members of the Ssm Diego County Water Authority is presented in Table 6. This table shows that about ^+89,300 acres are included within the boundaries of the San Diego County Water Authority, which is a member agency of The Metropolitan Water District of Southern California. Of this total, about 13U,700 acres, or 28 percent of the area, are devoted to laind uses requiring water service. This water service area represents 78 percent of the total water service area in San Diego County, and 75 percent of the total for the entire investigational area. 32 LAND USE IN MEMBER AGENCIES OF THE SAH DIEGO COUNTK WATER AUTHORITY IN 1958 Category and class of land '- San Diego County Water Authority City of Escondido City of National City City of Oceans Ide City of San Diego Helix Irrigation District Helix Irrigation District Overlap into City of San DleRO^ :San Dlegulto Irrigation District Santa Fe Irrigation District South Bay Irrigation District : South Bay : Irrigation ; District : Overlap : into : City of : San Dlego^ Bueno Colorado Municipal Water District Bueno Colorado Municipal Water District Overlap into City of Oceanside^ Carlsbad Municipal Water District CEirlsbad Municipal Water District Overlap into City of Oceanside^ Otay Municipal Water District Otay Municipal Water District Overlap Into City of San Dlego^ Poway Municipal Water District Rainbow Municipal Water District Rainbow RlQcon Municipal Ramona Del Diablo Rio Valley Water Municipal Municipal San Diego Center Public District Water Water Municipal Municipal Utility Overlap District District Water Water District into City of District District Oceanslde^ WATER SERVICE AflSA Urban aod Suburbaji Residential Connnerclal Industrial Unsegregated urban and suburban area Subtotals Included Honwater Service Area Gross Urban and Suburban Area Irrigated Agriculture Alfalfa Pasture Citrus and subtropical Truck crops Field crops Deciduous fruits and nuts Small grains Vineyards Subtotals Fallow Included Honwater Service Area Gross Irrigated Agriculture GROSS WATER SERVICE ABEA NOrtWATER SERVICE AREA Monlrrigated Agriculture Native Vegetation Unclassified GROSS HOHHATSR SERVICE AREA TOTA1£ 70 20 930 U70 l.IiOO 30 30 IBO 10 ko 1,150 ISO 20 » 1,380 1.030 2,U10 1,010 150 30 250 1,UI|0 8i0 2.290 170 290 1*30 70 10 70 90 6g 1,210 3,500 330 1,570 10,720 12,620 16.120 7,370 510 ko 230 8,150 5.580 13,730 260 1,990 Uio 30 ko TIB U30 2,7'<0 a 2,21i0 70 liO 280 160 10 50 a 20 JO 2rg HO 520 830 750 3.510 a 2,gho J20 380 2,020 100 l.OltO 120 1,130 5,530 100 3,960 60 20 60 150 2ltO 550 1,520 300 5,630 550 100 1,220 ko 820 10 10 10 10 30 b 360 10 90 61iO 60 10 790 5liO 1,330 570 1,000 2k0 350 210 560 ItO 80 3M 50 50 120 280 80 360 no 730 30 ■lO 30 160 3,180 1,590 950 5,720 Ml. 730 910 li.920 57,190 63,020 107.750 60 60 90 1,1U0 60 22 1.290 2,U10 10 50 1.530 1,590 u.ooo 1.720 20 180 3.050 180 3ltO 7,030 10.080 1.830 610 630 2,920 8,1>50 350 2,770 5.060 6,180 16.630 liO lUO 320 6.150 12.130 5.240 kMo 29,920 39,570 51.700 100 120 1.810 3.1it0 20 880 1.260 15.830 1.360 17,9lt0 1.360 21,060 io 50 360 210 630 910 2110 3.610 1*.050 I4.960 1.0 160 1.310 1.670 6,320 9.l»50 11,120 230 1.20 100 520 150 3,670 1.000 11.0 lUO 160 160 30 610 60 630 30 670 1.20 1.00 J20 J.0 860 1,210 1,060 390 710 320 1.00 520 JO 2U0 1,180 1,610 1,600 1.60 950 10 190 120 b 10 100 70 380 6,070 70 160 1.0 170 50 7I.O 570 260 30 190 30 70 1.210 790 220 10 520 1.220 180 ll,210 50 1.30 6,960 1,870 1..220 4,260 120 _22 160 610 170 120 290 1.1.0 220 61.0 7,730 2,160 l.,?50 i.,i.eo 1,820 9,31.0 3,760 5.1.10 5.1.30 12,690 2,980 1,01.0 1.380 1,270 2,1.60 2,860 1.580 70 l.,260 7.550 12,370 1.6.880 2,650 18,220 13,010 16,270 1.9,61.0 2,720 20. 01.0 22.350 20.030 S5.250 8.150 37,670 3,200 91.0 5.650 1.7,1.60 31.500 78,960 650 4,230 27,51.0 9,lllO 220 1,230 2,250 700 1.5,960 4,790 5,030 55.780 134,740 31,160 36,210 267.210 354,560 489.320 Overlapping acreage considered here as l£ss tnan 10 acres. being part of the city. e r^ * ^ Spence Air Photos 1950 Urban Expansion in San Diego, 1950 to 1957 ^p^"" ^'" ^^°'°' Recent Changes in Land Use Recent changes in land use in the area of investigation, are indica- ted by the data presented in Tahle J. This table lists the acreages of the various classes of land use determined from a survey made in the coastal portion of the investigational area in 19^, and from a I95O survey of the desert portion of the area, together with those resulting from the 195^ survey. The data indicate that during the period between the surveys, the gross area requiring water service increased 56, ^UX) acres, from 123,^*00 acres to 179,800 acres, or k6 percent, ^e gross urban and suburban water service area increased by 38,400 acres, or about 7U percent, and the gross irrigated agricultural water service area increased by l8,000 acres, or about 25 percent. Much of the urban and suburban development since 19^^ has occurred eilong the coastal strip from Oceanside south to San Diego, and also inland in the vicinity of El Cajon. Some of this urban and suburban development has been on lands formerly devoted to irrigated agriculture, particularly in the general vicinity of the City of San Diego. However, this has been more than offset by the expansion of irrigated agriculture into adjacent areas which were formerly undeveloped. The increases in both urban and suburban and irrigated agricultxiral acreages, in coastal San Diego County, have been made possible primarily throiJgh the increased availability and the use of water iii5)orted from the Colorado River. The recent changes which have occurred in the uses of land in the investigational airea are delineated on Plates 5A and 5B, "Change in Land Use, 191*8 to 1958." 35 Santa Margarita-San Luis Rey Unit (9-8) The gross water service eirea in the Seuita Margaurlta-Seua Luis Rey Unit increased about 11,200 acres, or 39 percent, between 19k& and 1958 • Approximately 3>000 acres of this total expansion were in urban and sub- urban developHient, and 8,200 acres were in irrigated sigricultural develop- ment. The crops accounting for most of the agricultural acreage increase were citrus euid subtropical fruits, pasture, and truck crops. San Dieguito-Cottonwood Unit (9-9) The gross urban and suburban area requiring water service in the San Dieguito-Cottonwood Unit increased from 3^900 acres in 191*8 to 11,800 acres in 1958, or about 200 percent, while the irrigated agricultural acreage increased from 21,000 acres to 2l4-,200 acres, or 15 percent. The largest increases in agricultural acreages resulted from increases in small grains and pasture areas, while acreages of citrus and subtropical fruits, and deciduous fruits and nuts decreased. San Diego Unit (9-10) Gross urban and suburban area in the Ssm Diego Unit increased from U3,300 acres in I9U8 to 70,200 acres in 1958, or about 62 percent. A portion of this increase occurred on lands formerly used for irrigated agriculture although, during the 10-year period, the gross irrigated agricultural acreage also increased about 5 percent, from 21,U00 acres in 19'*8 to 22,500 acres in 1958. Salton Sea Unit (7-3) The gross water service area in that portion of the Salton Sea Unit located in San Diego County expanded frcnn 2,900 acres in I95O to 8,000 36 c c c c c c 65,500 c Tl.UOO 123,^00 Ul,120 3,7^+0 990 9,070 5*^,920 35,500 52,000 90,1+20 5,800 6,li+o 5,700 10,300 30,800 31,870 13,500 13,090 1,700 1,750 3,U00 2,020 3,200 6,390 l.UOO 2,750 7U,300 6,650 8,380 89.3^0 179,760 Santa Margarlta-San Luis Rey Unit (9-8) The gross water service area in the Santa Msurgarita-San Luis Rey Unit increased about 11,200 acres, or 39 percent, between l^kQ and 1958. Approximately 3>000 acres of this total expemsion were in urban 6Uid sub- urban development, and 8,200 acres were in irrigated eigriciiltural develop- ment. The crops accounting for most of the agricultural acreage increase were citrus and subtropical fruits, pasture, and truck crops. San Dieguito-Cottonwood Unit (9-9) The gross urban and suburban area requiring water service in the San Dieguito-Cottonwood Unit increased from 3,900 acres in 191*8 to 11,800 acres in 1958, or about 200 percent, while the irrigated agricultural acreage increased from 21,000 acres to 2l*-,200 acres, or 15 percent. The largest increases in agricultural acreages resulted from increases in small grains and pasture eureas, while acreages of citrus and subtropical fruits, smd deciduous fruits and nuts decreased. San Diego Unit (9-10) Gross urban and suburban area in the San Diego Unit increased from 1*3,300 acres in I9U8 to 70,200 acres in 1958, or about 62 percent. A portion of this increase occurred on lands formerly used for irrigated agriculture although, during the 10-year period, the gross irrigated agricultural acreage also increased about 5 percent, from 21,^400 acres in 191+8 to 22,500 acres in 1958. Sal ton Sea Unit (7-3) The gross water service area in that portion of the SeJ.ton Sea IMit located in San Diego County expanded frcMi 2,900 acres in I950 to 8,000 36 i TABLE 7 LAND USE IN COASTAL SAN DIEGO COUNTY AND SOUTHWESTERN RIVERSIDE COUNTY IN I9U8 AND 1958 AND IN THE DESERT PORTION OF SAN DIEGO COUNTY IN I95O AND I958 In Acres md Use Hydrographic Unit Totals 191*8^ Category and Class of L San Juan Capistrano^ (9-7) Santa Margarlta- San Luis Rey (9-8) San Dieguito- Cottonwood (9-9) San Diego (9-10) Coachella Valley (7-2) Salton Sea (7-3) Totals 1958 191*5 : 1958 191*8 : 1958 191*8 : 1958 191*8 : 1958 1950 : 1958 1950 : 1958 WATER SERVICE AREA Urban and Suburban Residential Connnercial Industrial Unsegregated urban and sul burban area c c 2,900 380 70 1,990 5,31*0 c c c 5,020 550 70 2,830 8,1*70 17,800 1,800 300 5,3001 25,200 32,920 2,780 81*0 i*,i6o 1*0,700 p p c c c c c 280 30 10 90 1*10 c c c c c 1*1,120 3,71*0 990 9,070 Subtotals 3,100 2,700 51*, 920 Included Nonwater Service Area rban Area 1,1*00 1*,500 2,170 7,510 1,200 3,900 3,310 11,780 18,100 1*3,300 29,530 70,230 p p c 300 1+^ 900 c 35,500 Gross Urban and SubU] 52,000 90,1*20 Irrigated Agriculture Alfalfa Pasture Citrus and subtropiCELl Truck crops Field crops Deciduous fruits and nuts Small grains Vineyards p 2,800 2,300 8,000 1*,1*00 700 1,200 3,100 e 2,1*20 It, 320 13,21*0 5,680 860 860 1,1*20 170 28,970 1,000 1,700 11*, 700 1,600 300 1,600 100 e 1,010 3,560 13,320 1,21*0 50 960 3,500 550 2l*,190 1,500 1,600 8,000 7,1*00 1*00 600 e 1,100 1,950 5,220 5,750 1*60 11*0 890 1*0 15,550 p p 500 100 100 100 300 1,1*00 2,500 1,610 1*70 90 1*20 380 60 580 i,9?o 5,600 5,800 5,700 30,800 13,500 1,700 3,1*00 3,200 1,1*00 65,500 6,11*0 10,300 31,870 13,090 1,750 2,020 6,390 2,750 Subtotals 22,500 21,000 19,500 74,300 Fallow Included Nonwater Service Area p c 1,800 1,360 2,160 c 2,100 960 2,180 c 1,900 1*,260 2,650 p c 100 110 1,360 c 5,^0 6,650 8,380 Gross Irrigated Agriculture 21*, 300 32,1*90 23,100 27,330 21,1*00 22,1*60 p p 2,600 7,060 71,1*00 89,340 GROSS WATER SEHVICE ftREA 28,800 1*0,000 27,000 39,110 61*, 700 92,690 2,900 7,960 123,1*00 179,760 a. All land use requiring applied water is within a military reservation, and appears in the category "unclassified" . b. Includes acreages in Salton Sea Hydrographic Unit in 1950. c . Value not available . d. Value includes schools and institutions, which have been grouped with the commercial category in 1958. e. Acreages for vineyards are grouped with field crops. acres in 1958^ or about 176 i)ercent. The gross urban ajid suburban acreage increased from 3OO acres in I95O to 900 acres in 1958, and the gross irri- gated agricultural acreage increased from 2,600 acres to 7,100 acres or about 173 percent, during the 8-year period. Much of the expansion in irrigated agriculture occurred in Borrego Valley Trtiere relatively large acreages of alfeilfa and vineyeurds were planted. Multiple Cropped Areas In all of the major agricultural areas covered by the investiga- tion, short, mild winters make possible raising crops 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, a large portion of this fallow land will 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 on data collected during the summer survey would not be truly representative of conditions in the study eirea. Previous studies, conducted by the department to determine the disposition of fallow acreage for the entire yeajr in areas with somewhat similar climatic conditions and farming cultural practices, such as Orange, Santa Barbgira, and San Luis Obispo Counties, were used in this report as the basis for distributing fallow acreage in the coastal portion of the investi- gational area into the appropriate type of irrigated crop. These studies consisted of making three supplemental resurveys to determine the types of crops planted in this fallow acreage. Distribution of fetLlow acreage in the desert portion of the investigational area was based on three supplemental 37 resurveys conducted during Novemiber, February, and May following the main survey in Borrego Valley. During each of the resurveys, the type and areal extent of crops planted in this fallow acreage, subsequent to the main summer 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, dirring the axial- ysis of the resurvey data from ■vrtiich the percentages shown in Table 8 were derived, these factors were not considered. Instead, the type and eureal 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 assigning unit use values. That parcel was then removed from the fallow classification for the remainder of the study period. It should be pointed out 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 coastal San Diego County and the desert portion of the county, about 20 percent and 8k percent, respectively, of the total area indicated as fallow during the summer survey remained fallow throiighout the entire year, lie remaining lajad, which had been mapped fallow during the main survey, was found during the subsequent resurveys to be planted to the various crops in the percent- ages shown on Table 8. 38 TABLE 8 DISPOSITION OF ACREAGE POUND FALLOW IN SUMMER 1958 In percent of svunmer fallow acreage Type of land use : Coast€il : :San Diego County: Borrego Valley Area remaining fallow all year 20 8U Irrigated crop plantings Pastiire 5 Truck crops 65 11^ Pleld crops 10 Small grains 2 Totals 100 100 The percentage values given in Table 8 were used as the basis for distributing the fallow acreages determined from the 1958 svumaer survey into the appropriate crops for determining water reqtiirements . However, the acreage values for irrigated crops presented in Tables k, 5> 6, 7 and Appendix B which show the land use dxiring the stimmer of 1958 have not been modified to reflect these increases. 39 1 C:L-i.PTiJ3^ IV. WATER USE Land areas occupied by various types of v.'-ater-usinc develop- r.ient in San Diego County and the portion of soutlrjestern Riverside County described in Chapter III, and appropriate unit values of water use were employed in this investigation to estii.iate the 1958 level of ■s.'ater use. This chapter presents the estimates of water use so derived, and the change in water use since previous estimates 'jere made. Also presented is a discussion of the relationships between estimated levels of water use and available water supplies for the coastal portion of the investigational area comprising Hydrographic Units T, 3, 9^ and 10. 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- made modifications of those natural conditions. It implies the applica- tion of water to any one, or all, of innumerable kinds of uses, both consumptive and nonconsuxiptive. Constimptive use includes the vmter from any source utilized in the process of vegetative growth, such as transpiration and the building of plant tissue, and the ijater evaporated from the soil around the plant and foliage, as well as from v/ater surfaces. It also includes the water consiomed or evaporated 'oy 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 irrecoverable losses include such items as disposal or seepage of the unconsumed water to bodies of unsuitable quality including the ocean. kl emd disposal or seepage of the •unconstimed water in such a manner as to be uneconomic aJ. of recapture for use. The water for consumptive use is obtained from two general sources: natural sources including direct precipitation and soirface runoff, and, as a special case, from a high ground water table; and man- developed sovirces, that is, water applied throtigh the activities of man. Water furnished from this latter source is termed "applied water." Man applies water to satisfy the consumptive use in excess of that supplied from natxiral 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 amoiint 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 in areas where none of the applied water beccmes available for reuse, it is possible to determine the net water use by measuring the total water applied. On the other hand, in areas where a portion of the applied water becomes available for reuse, economic and technological limitations generally preclude measurement of the volume of return flow of reusable water. The net water use in these areas must be determined in another m a nn er; therefore, an indirect method is used. U2 Using the indirect method commonly employed, estimates of net water use are obtained by multiplying the areas of the various classes of water-using developnents by appropriate average values of iinit water use. These unit values of water use reflect average conditions of precipitation and the normal practices associated with urbem water distri- bution and with irrigated agriculture. Variations from normal or average in these factors during the specific year that a lajid use survey is conducted may result in a difference between the estimated and actual water use diiring 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 in planning for such additionsil supplies as will be necessary to meet ciirrent or expected futiire deficiencies. Unit Values of Water Use During this investigation vmit values of water use derived in Bulletin No. 2 were reviewed in order to determine the applicability of the values to 1958 conditions of developnent. The results of this review indicate that, in general, mean seasonal unit values derived in that bulletin for urban and suburban areas for 19^ are still applicable. Mean seasonal unit values of consumptive use of applied water for irrigated agricultural land were derived frcan data developed dviring prior investigations by the department, including the statewide studies reported in Bulletin No. 2, and detailed studies in Ventura County and in the Santa Margarita River watershed in San Diego County. ^3 A complete discussion of the techniques employed in the deriva- tion of units of water use is contained in Bulletin No. 2, therefore, only a general description of those procedures is set forth herein. Urhan Water Use Values Mean seasonal unit values of consxjmptive use of water on urban and suburban lands were derived from (l) estimates of the constunptive use on the area occupied by impervious cover, bare lands, lawns, shrubs, etc., ajid (2) estimates of other urban consumptive uses, such as house- hold uses, etc. The meajn seasonal unit vsilues of consumptive use of water so determined are presented in Table 9. These values were utilized to compute net water use in areas of the investigation where applied water in excess of consumptive use is generally considered to be available for reuse through deep percolation or salvage. TABLE 9 ESTIMATED MEAN SEASONAL UNIT VALUES OF CONSUMPTIVE USE OF WATER ON URBAN AND SUBURBAN LANDS IN SAN DIEGO COUNTY In feet of depth per vinit of area i Consumptive use of Hydrographic unit ; applied water Santa Margarita- San Luis Rey (9-8) 0.7 San Dieguito- Cottonwood (9-9) 0«^ San Diego (9-10) 0.6 Salton Sea (7-3) 1'6 Mean seasonal unit values of delivery of water to urban ajid suburban types of land use in the San Diego Hydrographic Unit No. 10, were estimated from svirveys which determined total water deliveries to known areas occupied by the various types of land use. kk Table 10 lists estimated net deliveries of water to various land use types in the San Diego Hydrographic Unit. TABLE 10 ESTIMATED MEAK SEASONAL UNIT VALUES OF WATER DELIVERY TO URBAN AND SUBURBAN LANDS, SAN DIEGO HYDROGRAPHIC UNIT In feet of deirth per unit of area : Unit Land use type : delivery Residential; single 2.4 Residential, multiple 7.4 Residential, rural 2.2 Commercial, strip 3-7 Commercial, downtown 28.6 Industrial, manufacturing 11.8 Schools 1.8 Institutions 1.8 Dairies 1.1 Livestock and poultry reinches 0.6 Parks, etc., with lawns 1.1 These ^jnit values of water delivery were utilized to compute net water use in the areas of Hydrographic Unit No. 10 where percolation losses incidental to the delivery and use of water are generally not considered a-vailable for reuse. Unit Values of Water on Irrigated Agriculture Unit seasonal values of consumptive use of water by irrigated crops were derived by a modification of a method developed by Harry F. Blaney and Wayne D. Criddle of the United States Department of Agriculture. The increased use of water resulting from multiple cropping practices was considered in estimating average unit values of applied water use for truck crops. The values thus derived are presented in Table 11. 45 The values shown in Table 11 represent estimates of the average consumptive use of applied water and precipitation by the various types of irrigated agricvilture. Available data indicate that an average irrigation efficiency of about 70 percent is being achieved in the in- vest igationeil area, eind this value was utilized to estimate total use of applied water in areas where riinoff from irrigation emd deep percolation are not available for reuse. The toteil use of applied water was computed by dividing the consumptive use of applied water by O.7O. It should be ix)inted out that, in the derivation of the net water use for einy given year, the volume of applied water required is based on the assumption that the precipitation for the season was approximately equal to the long-time mean. However, the use of applied water will actually be somewhat larger or smaller in individual years, varying inversely with the amount of rainfall. A similar effect occxurs in the instance of urban use. How- ever, the use of precipitation by residential, commercial and industrial classifications is relatively small. Therefore, variations of rainfall from year to yeair have a lesser effect upon the use of applied water on these land use classes than on irrigated lands. Net Water Use * Estimates of the amount of net water use in the investigational area, imder 1958 conditions of development, assuming normal precipita- tion, are presented in this section. As previously indicated, net water use was estimated by applying to the net areas of each type of land use the mean seasonal unit values of water delivery in areas where no water is available for reuse, and unit values of consumptive use of water where the \inused portion is available for reuse. Thus, consideration U6 lOUS i nuts ipi- ion Total Small grains 2.7 2.7 Applied :Precipi- : ^^-.g^-L water : tation : Vineyards Applied :Precipi- water : tation 0.3 0.2 1.2 1.1+ 1.5 1.6 1.5 1.5 1.2 1.2 Total > 2.8 0.3 1.1 1.!+ 1.1 1.0 2.1 ) 2.9 O.U 0.9 1.3 1.3 0.8 2.1 5 2.5 0.5 1.0 1.5 0.8 1.1 1.9 ) 2.6 0.5 1.0 1.5 l.U 0.9 2.3 2.8 0.6 0.9 1.5 1.5 0.8 2.3 5 2.7 0.5 1.0 1.5 1.1 0.8 1.9 2.6 0.6 0.8 l.U 1.6 1.0 2.6 2.8 0.6 0.9 1.5 1.6 1.2 2,8 2.6 0.5 1.0 1.5 1.1+ 1.2 2.6 2.7 2.7 2.6 2.6 O.U 1.8 1.2 0.3 1.6 2.1 1.8 3.6 0.8 0.3 2.6 3.9 The values shown in Table 11 represent estimates of the average consumptive use of applied water and precipitation by the various types of irrigated stgricvLLture. Available data indicate that an average irrigation efficiency of about 70 percent is being achieved in the in- vestigational area, and this veilue was utilized to estimate total use of applied water in areas where runoff from irrigation and deep percolation are not available for reuse. The total use of applied water was computed by dividing the consumptive use of applied water by O.7O. It should be pointed out that, in the derivation of the net water use for any given yeair, the volume of applied water required is based on the assumption that the precipitation for the season was approximately equal to the long-time mean. However, the use of applied water will actually be somewhat larger or smaller in individual years, varying inversely with the amount of rainfall. A similar effect occurs in the instance of urban use. How- ever, the use of precipitation by residential, commercial and industrial classifications is relatively small. Therefore, variations of rainfall from year to year have a lesser effect upon the use of applied water on these land use classes than on irrigated lemds. Net Water Use *" Estimates of the amount of net water use in the investigational area, under 1958 conditions of development, assuming normal precipita- tion, are presented in this section. As previously indicated, net water use was estimated by applying to the net areas of each type of land use the mean seasonal unit values of water delivery in areas where no water is available for reuse, and unit values of consumptive use of water where the iinused portion is available for reuse. Thus, consideration k6 ESTIMATED MEAN SEASONAL UNIT VALUES OF CONSUMPTIVE USE OP WATER ON IRRIGATED LANDS IN SAN DIEGO COUNTY In feet of depth per unit of area Hydrographic Unit Applied rPrecipi-T rj.^^^^^ wat e r : tation : Applied :Preclpi-: ^^^^ water : tation : Applied :Precipi-: ^^^^-^ water : tation : Applied :Precipi- water : tation Truck Crops Applied rPrecipi- water : tation Applied rPrecipi- : water : tation : Miscellaneous field crops Applied rPrecipi- water : tation Deciduous f ru it and nut s Applied :Precipi- : water : tation : Small r;rains Applied rPrecipi- water : tation Vineyards Applied :Precipi-: water : tation : Santa Margarita-San Luis Rey Santa Margarita River Coastal Central Interior San Luis Rey River Coastal Central Interior San Dieguito-Cottonwood San Dleguito River Coastal Central Interior Cottonwood Coastal Interior San Diego Coastal Salton See 2.1 2.8 2.1 2.2 2.6 2.2 1.1 0.9 1.2 1.0 1.0 1.2 3.2 2.1 1.1 3.T 2.8 0.9 3-3 2.1 1.2 3.2 2.2 1.0 3.6 2.6 1.0 3.h. 2.2 1.2 2.3 1.0 3-3 2.3 1.0 2.5 1.1 3.6 2.5 1.1 2.3 1.2 3.5 2.3 1.2 2.1 1.2 3-3 2.2 1.1 2.2 l.lt 3.6 2.1. 1.2 2.U 0.9 3.3 2.U 0.9 14.2 0.3 14.5 5.0 0.3 3.2 1.1 1.0 3.7 1.3 0.8 3.3 3.2 1.2 1.0 3.6 1.3 1.1 3.I4 1.3 1.0 3.3 1.3 0.9 3.6 l.U 0.9 3.5 1.3 1.0 3.3 1.2 1.1 3.6 1.3 1.2 3.3 l.". 0.9 5.3 it.o 0.3 2.1 1.3 1.0 2-3 1.0 1.0 2.1 1-5 0.8 2-3 1.1 o.s _ _ _ _ 0.8 1.1 2.2 1.5 1.0 2.1* 1.6 0.9 2.3 1.5 1.0 2.2 1.5 0.9 2.3 1.6 0.9 2.3 1.5 1.0 2.3 1.14 1.1 2.5 1.5 1.2 2.3 1.5 0.9 I4.3 2.5 1.1 0.8 2.5 1.2 0.8 2.5 1.0 0.3 2.h 1.2 0.8 2.5 1.3 0.8 2.5 1.1 0.9 2.5 1.2 0.9 2.7 1.3 0.8 2.1) I.I4 0.7 3.0 0.3 2.0 0.8 1.1 1.9 1.0 0.9 1.9 1.9 0.8 0.8 2.0 1.1 0.8 1.8 0.9 0.8 2.0 0.8 0.8 2.1 1.2 0.8 2.0 0.8 0.8 2.1 1.2 0.8 2.1 1.2 0.8 2.1 1.3 0.7 3.3 1.9 1.1 1.0 1.9 1.2 0.8 0.9 1.1 1.6 I.I4 0.6 1.9 1.2 0.9 1.7 1.1 1.1 1.6 l.lt 0.6 3.0 1.2 1.1 1.6 1.2 1.1 2.0 l.U 0.6 2.0 1.2 1.1 2.0 l.li 0.6 2.I4 0.3 2.1 1.6 1.2 2.0 1.9 1.0 2.0 1.2 1.3 2.0 1.6 1.0 2.1 1.7 1.1 2.2 I.I4 1.3 2.0 1.6 1.0 2.3 1.6 1.2 2.3 1.1» 1.2 2.0 1.5 1.2 2.3 1.5 1.2 2.0 1.8 0.8 2.7 2.3 0.3 2.8 0.3 1.1 2.9 O.I4 0.9 2.5 0.5 1.0 2.6 0.5 1.0 2.8 0.6 0.9 2.7 0.5 1.0 2.6 0.6 0.8 2.8 0.6 0.9 2.6 0.5 1.0 2.7 0.3 1.2 2.7 0.2 l.ll 2.6 O.li 1.2 2.6 1.8 0.3 l.ll 1.1 1.0 1.3 1.3 0.8 1.5 0.8 1.1 1.5 I.I4 0.9 1.5 1.5 0.8 1.5 1.1 0.8 l.ll 1.6 1.0 1.5 1.6 1.2 1.5 l.lt 1.2 2.1 2.1 1.9 2.3 2-3 1.9 2.6 2.8 2.6 1.5 1.5 1.2 2.7 1.6 1.5 1.2 2.7 1.6 1.8 0.8 2.6 2.1 3.6 0.3 3-9 was given to the disposition of the unconsumed portion of the vater delivered, with regard to its availability for reuse, and to losses incurred in conveyance of water to its place of use. The estimated ajnounts of mean seasonal net water use in hydro- graphic units of San Diego County and a portion of southwestern Riverside County for conditions of 1958 are presented in Table 12. For comparative purposes, values estimated for conditions of 19^8 are also presented. As indicated previously, the unit values used to derive the net water use represent the optimum needs of the various types of water- using developments for average conditions of rainfall and climate, and therefore provide comparable estimates which show general level of water use. The actual water use may have differed from the estimated values derived herein because of variations from the mean in precipitation. Averages of data from representative precipitation stations located in the investigational area indicate that rainfall during 19^8 was about 6o percent of normal for the 50-year period, 1897-98 through ISkS-kJ, and during 1958 about 135 percent of this normal, although runoff in the southern part of the county was considerably below normal. Therefore, the estimates of the level of net water use shown in Table 12 for 1948 are probably on the low side as compared to actual water use, and on the high side for 1958. The difference between estimates for the two years shown, however, is considered to represent a reasonable estimate of the increase in water use. The data presented in Table 12 indicate that changes in net water use generally reflect the chsmges in land use presented in Chapter III. There was an increase in estimated seasonal net water use of about hi 62,900 acre-feet between 1948 and 1958 with the increase being rather equally distributed between irrigated agriculture and urban uses. TABIE 12 ESTIMATED NET WATER USE IN SAN DIEGO COUWrf AND A PORTION OF SOUTHWESTERN RIVERSIDE courmr for conditions of developmewt IN 1948 AND 1958 In acre-feet Hydrographic unit 1948 1958 .Difference Santa hfergarita-San Luis Rey Unit Irrigated Lands Urban- Suburban Areas Totals San Dieguito-Cottonwood Unit Irrigated Lands Urban- Suburban Areas Totals San Diego Unit Irrigated Lands Urban-Suburban Areas Totals Salton Sea Unit 31,100 4,400 35,500 29,800 2,500 32,300 31,000 77,900 108, 900 45,700 7,500 53,200 34, 300 7,700 42, 000 34,700 97,800 132, 500 14, 600 3,100 17,700 4,500 5,200 9,700 3,700 19,900 23,600 Irrigated Lands Urban- Suburban Areas 9,100 " 500 20,000 1,500 10,900 1,000 Totals 9,600 21,500 11,900 Total Investigational Area Irrigated Lands Urban-Suburban Areas 101,000 85, 300 134,700 114, 500 33,700 29,200 GRAND TOTALS 186, 300 249,200 62,900 48 Comparison of Water Supply and Water Use The amovmts of net water use for various years, determined from land use surveys conducted in the coastal portion of the investiga- tional area beginning in 1933, are shown on Table 13, together with the mean ajinual net local water supply which was derived in Chapter II. Also shown on Table 13 is an historiceil comparison between the excess of water use over the approximate mean annual safe yield of local water supplies, and the quantity of imported water. The forecast net water requirement for the year 2020 for the coastal portion of the investigated area, as derived from studies for Bulletin No. 78, is also presented in Table 13 . TABLE 13 CCMPARISON OF NET WATER USE AND WATER SUPPLY OF COASTAL SAN DIEGO COUNTY AND A PORTION OF SOUTHWESTERN RIVERSIDE COUNTY In acre- feet Date of stirvey ; : :Approximate mean :Excess of water use: : Net : annual safe yield: over mean annual : • water use : of local water :safe yield of local: : : supplies : water supplies : Historical imports from Colorado River 1933 1948 1958 2020 77,000* 177,000 228,000 1,117,000^ 79,000* 124,000 53,000 124, 000 104, 000 124,000 993,000 59,000 136,000 a. Includes only coastal San Diego County. b. Water requirement. The data presented in Table 13 indicate that sometime during the middle 1930 's, the net water use in the investigational area began to exceed the approximate mean sinnual net local water supply. The deficiency in local supplies was met, in part, by overdraft of the surface 49 water reservoirs and grotmd water "basins. In 19^7-^*8 the deficiency was alleviated by importation through the San Diego Aqueduct and the Colorado River Aqueduct of The Metropolitan Water District of Southern California. Table 13 also shows that after 19^7-^ the sum of the approx- imate mesm annual safe yield of local water supplies, and the imports, exceeded the net water use. As indicated earlier, during periods of deficient supply between the time when the net water use began to exceed the approximate mean annusil net local water supply, and 19^7-^* when imported water became available, the net water use in excess of safe yield was met by overdraft on the accimiiilated surface and groxrnd water storage. The supplies in storsige reached critical stages of depletion by 19^7-^^ and the recent succession of dry yeeirs has precluded replenishment of reserves; therefore, only a portion of the local safe yield has been available. A portion of the difference between the deficit and the importation shown in Table 13 is accounted for by in- creased storage in San Vicente Reservoir which is one of the major points of retention of Colorado River water. As previously pointed out, in certain of the areas of the county where imported supplies are available the sustained yield method of operating surface reservoirs has been altered. These surface reser- voirs are now emptied as soon as is practical in order to reduce evaporation losses to a minimum. This fact is evident from the records of seasonal deliveries of imported water shown in Table 2 of Chapter II. It may be noted that during the periods from 1951 to 195^ and 1957-58* when increased rainfall made available additionsil water to surface and ground water reservoirs, the volxmies of imports were appreciably reduced. 50 studies developed for Bulletin No. 78 indicate that 'the estimated total seasonal water requirement for the coastal portion of the area of investigation will be about 1,117,000 acre- feet by the year 2020. The increase in net water use between the present and year 2020 is anticipated to be the result of developnent of about 371,800 acres of land considered susceptible of intensive water using developnent by 2020, but not c\xrrently receiving water sei-vice. Of this requirement, approx- imately 993 f 000 acre- feet must be derived by importing supplies from beyond the area. 51 CHAPTER V. SUMMARY AND CONCLUSIONS The results of the 1958 land and vater use survey of San Diego bounty and a portion of Riverside County, comparisons with the l^kS survey results, and conclusions dravn from this study are summarized in this chapter. SummsLTy This investigation disclosed that the follovd.ng land uses and water requirements existed in the area of investigation: 1. A total of 179,800 acres, or about 6 percent, of all lands idthin the surveyed asea, had "been developed for urbein aind suburban, or irrigated agricviltural uses by 1958' This is an increase of about k6 percent 3ver similar water-using developments that existed in 19^. 2. The gross urhan emd suburban ajrea in 1958 was 90^ '♦^ acres, an increase of about 38,UOO acres or Jh percent over that \rtiich existed in 19^. Ihis increase was a direct result of an increase in population in San Diego County from 556,800 in I95O to 1,033,000 in i960. In the coastal portion of the study area, the gross urbein amd suburban area was about 89,500 acres, vrtiich equaled about 25 percent of the 352,000 acres considered susceptible of intensive urban development by the year 2020. 3. The gross irrigated agricultural area in I958 was about 89,i«D0 acres, an increase of 25 percent over the 71,ltO0 acres that existed in I9I48. The net irrigated agricultural acreage in the coastal portion of the study area was about 68,700 acres in 1958 and this is about 39 percent of the 178,000 acres ^ich is forecast by the yeair 2020. k. The estimated I958 mean seasonal level of net water use by these water-using developments was about 2^^9,200 acre-feet. This is an 53 increase of about 62,900 acre-feet, or approximately 3^ percent, over the 19^8 estimated net water use level. 5. The net water use in the investigational area has exceeded the approximate mesua annual net local water supply from about the middle 1930' s to the present time. During this period, the deficiency in local supplies was met, in part, by overdraft of the surface water reservoirs and ground water basins. In 19i^7-U8, the deficiency was silleviated by imported water from the Colorado River. 6. The seasonal volume of Coloreido River water imported to the investigational area, increased ffcm 59,000 acre-feet in 19kj-kQ to 136,000 acre-feet in 1957-58' This increase was used largely to meet the increased water use in the investigational axea. 7- The estimated total seasonal water requirement for the coastal portion of the investigational area by the year 2020 has been estimated to be on the order of 1,117,000 acre-feet. Of this requirement, approximately 993>000 acre-feet must be derived by importing sujrplies from outside the area of investigation. f Conclusions Based on the results of this investigation, it is concluded that: 1. Economic emd climatic factors have established a rapid rate of growth in population, industry, and agriculture in the axea of investigation, and this growth will probably continue in the foreseeable future if adequate water supplies are available. 2. A large increase in the volume of water imported to the area will be required to meet the emticipated growth. This large volume of iniporU 5i+ water can be made available only by a program of comprehensive planning and development of water resources. 3. The l6Uid uses, water requirements, and growth trends estab- lished by this study should be monitored suid re-evaluated by future land use siirveys in order that the water supplies required to support such growth can be adequately planned and developed. 55 PLATE I STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY AREA OF INVESTIGATION 1958 .0 SCALE OF MILES _J io 50 AREA INVESTIGATION .- ♦ * « I I i I HYDROGRAPHIC AREAS AND UNITS PORTION OF COLORADO DESERT HYDROGRAPHIC AREA T-Z PORTION OF COACHELUA VALLEY UNIT T-3 PORTION OF SALTON SEA UNIT PORTION OF SOUTH COASTAL AREA "7 PORTION OF SAN JUAN CAPISTRANO UNIl 9-8 SANTA MARGARITA - SAN LUIS REY UNIT 9-9 SAN DIEGUITO - COTTONWOOD UNIT 9-IO SAN OlEGO UNIT LEGEND ' ' I BOUNDARY or INVESTIGATIONAL AREA - ^ BOUNDARY OF HYDROGRAPHIC AREA —' BOUNDARY OF HYDROGRAPHIC UNIT MEMBER AGENCIES OF SAN OlEGO COUNTY WATER AUTHORITY IN 1958 BUENO COLORADO MUNICIPAL WATER DISTRICT •77777^. CITY OF SAN OlEGO CITY OF ESCONDIDO I CITY OF NATIONAL CITY CITY OF OCEANSIDE I HELIX IRRIGATION DISTRICT SAN DIEGUITO IRRIGATION DISTRICT S^NTA FE IRRIGATION DISTRICT SOUTH BAT IRRIGATION DISTRICT CARLSBAD MUNICIPAL WATER DISTRICT OTAY MUNICIPAL WATER DISTRICT ICIPAL WATER DISTRICT RAINBOW MUNICIPAL WATER DISTRICT RAMONA MUNICIPAL WATER DISTRICT POWAY MUNK A HlO SAN OlEGO MUNICIPAL WATER DISTRICT '~\ VALLEY CENTER MUNICIPAL WATER DISTRICT j fallbrook Public utility district 7-3 HYDROGRAPHIC UNIT NUMBERS STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY MAJOR WATER AGENCIES AND HYDROGRAPHIC UNITS SCALE OF MILE5 PLATE 3 NUMERICAL DESIGNATIONS OF HrOROLOGIC UNITS AND SUBUMTS PORTION OF COLOB400 DESERT REGION T-a.oo Coaoball* VtUay T-Z2.0O M»9t 3alt«n Sa* ViUay 7-23.00 a*rk VAUay 1-2h.00 domgo V>U«7 T-2S.0O OootLllD rails? 7-27.00 Sui Fallpa T<1I«7 T-26,«l V»UBOlto-C«rrllo ViU^j 7-29.CO CoyoU W«U« nUwr 7-J.6.00 7-l,7.M Jurnib* ViUar PORTION Of SAN DIEOO REGION ArrojT San Ocofra Rjdrtiloela Dnlt J-13.00 MJi.OO Santa Kargarlta Fdrar flTtlratoelc Unit MiliOI Kurrleta Cnak balov Vail RaaarvoU Mb. 02 IWaaaiila Cnak abore Vail Raaarroir 9Jll.CJ Laniuat«ri.Coabulla Crack abor* Vall Hasarvolr SulluDli ftamalndar of Taaaeula Craak baloo Vall Raaai-rol MJi.05 Santa Kargarlta Rlrar frm Oaga at TaBeoiila Cai^oD to Oa bu Da Slu Vlli.06 Santa KartarlU HlTer fro Da Lua Sn Slt« 3«n Lola Hs^ ItlTer Rr^raloele U San Lola Ref ftlTar a' a Hanshaw Dan San Lula Ray RlTsr tstmen Honshaw On and EaMndldo mieh Intaka 9-1S.03 San Lois Hay HlTor betwaen EaooraU-do Ditch Intaka tai Slokler'a KHI nsar F«la 9.1^.0(1 San iola Ray Rl*ar batnem Slokler'a KUl oear Pals and Konaaratc Iknintaln ?>1$,0S San Lula Rey Rlvor batmen HonseraU) Kountaln UA BonsoU 9«1S.06 Swi Lula Ray RlTar bcluwin Bonaall and Nair Bonaall 9iJ.S>07 San Lula Ray Rlrar batwaen Naar Bonaall and at Ooaanalda MA.n carlabad ItydroloKlD Unit 9>d6aal EMWdidc Creak froa Loka wotalford te Coast !«16.02 San Harcos, tpa Hadionda, and Endnltoa CraakB M^.03 Buana Vista Craak SUL6.OI1 Eaoendldc Creak abora Lake Mohlford 9-17.X San Dlagolto Hyitralocla Onlt 9-17. 01 Santa Taabol Craak abonra Santa lEabal 9-17,03 Santa Ttabel Creek batmen SanU Taabol and Sulbarland Dbb S^7.03 Santa Taabal Cr«ak between Sutherland tmi and Faao Db> Site 9^7.0U Ooljlte Cnek above San DlBculto FUTer MT.lego Rl*Br batman OlTertlnR Qdi anl □ Capltan D^ San Dleeo Wvar between Q Capltan Das and Lakeside San Vicente Creak abore San Vloante Da Alvarado Canyon abon Hurray Daa Sao Diego ftlver batvean Lakeside and CQd HlaiHai Dan azoludlng San Vicente Ctvek 9^9,09 San Diaeo Rlrer betmen Old HlBstcn tm and Old Inn exoluding Uvarado Canyon above Hurray Obi 9-20.00 Sao tUego Hyi'^PCio ^^^^ 9-ZL.OO SMRBtvater aiver Hydrologlc Unit 9-21.01 SmetUBter UTer above Daecanao 9S.,CZ 3mfltHater River betmen Daacanao and Loveland Da> 9>Z1.03 3metmtar Hirer batmen I^ireland Dan and SKeatnter 9.a.0U Smetntar River batman ±veet>.ater Dan and Bey 9-22.0O Otay River Hydjnloglo Unit 9-2;,Ql OUy River above Lowr CrUy Daa axolMdlng Proctor Tallef 9-n.m Proctor ValJoy above UR»r OUy Das 9-22.03 Otay River batmen Lomr OUy Dan and Say 9-23.00 Tla Joana River Hydreloglo (Wt 9-23. Ca Cottcmrood Creak above Barrett Dan oxoladlng Cottorwood Creek above Moreno Daa 9-23.02 Cottonvood Creak above KoreDO Da* 9-23.03 tla Juana River Drainage Area In California akdlBdijig CottorwoDd Creak above Barrett Dai and TU Juana Valley 9-23.0(i Hlpass Sotmlt 9-19.00 9 BOUNDARY OF INVESTIGATIONAL AREA BOUNDARY OF HYDROGRAPHIC AREA ■ BOUNDARY OF HYDROGRAPHIC UNIT BOUNDARY OF FEDERAL AND STATE LANDS IRRIGATED AGRICULTURE URBAN RESIDENTIAL COMMERCIAL NDUSTRIAL-MANUFACTURING AND PROCESSING INDUSTRIAL - EXTRACTIVE, STORAGE, AND TRANSPORTATION Y/////\ MILITARY RESERVATIONS 9-9 HYDROGRAPHIC UNIT NUMBER STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY PRESENT LAND USE 1958 SCALE OF MILES 2 HYDROGRAPHIC AREAS AND UNITS PORTION OF COLORADO DESERT AREA 7 — 2 PORTION OF COflCMELLfl VALLEt UNIT 7 — 3 PORTION OF SALTON SEA UNIT PORTION OF SOUTH COASTAL AREA 9 — 7 PORTION OF SAN JUAN CAPISTRANO UNIT 9-8 SANTA MARGARITA - SAN LUIS REY UNIT 9 — 9 SAN DIEGUITO - COTTONWOOD UNIT 9— lO SAN DIEGO UNIT PLATE 4B LEGEND / BOUNDARY OF INVESTIGATIONAL AREA BOUNDARY OF HYDROGRAPHIC AREA BOUNDARY OF HYDROGRAPHIC UNIT BOUNDARY OF FEDERAL AND STATE LANDS IRRIGATED AGRICULTURE URBAN RESIDENTIAL COMMERCIAL INDUSTRIAL -MANUFACTURING AND PROCESSING <«;l INDUSTRIAL - EXTRACTIVE. STORAGE, AND ^1 TRANSPORTATION MIXED INDUSTRIAL. COMMERCIAL. RESIDENTIAL. AND VACANT LANDS DETERMINED BY CITY OF SAN DIEGO ISEE TEXT] Y/////X MILITARY RESERVATIONS ^^Jk ^ ^^ HYDROGRAPHIC UNIT NUMBER STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY PRESENT LAND USE 1958 SCALE OF MILES HYDROGRAPHIC AREAS AND UNITS PORTION OF COLORADO DESERT AREA ' -^_2 PORTION OF COACMELLA VALLEY UNIT 7-3 PORTION OF SALTON SEA UNIT PORTION OF SOUTH COASTAL AREA 9-7 PORTION OF SAN JUAN CAPISTRANO UNIT 9—8 SANTA MARGARITA - SAN LUIS REY UNIT 9 — 9 SAN DIEGUITO - COTTONWOOD UNIT 9 - lO SAN OIEGO UNIT LOCATION MAP 9-9- DEPARTMENT Or WATER RESOURCES PRESENT LAND USE 1958 PLATE 5A H T-2 7-3 9-7 9-6 9-P 9-10 LOCATION MAP LEGEND ' BOUNDARY OF INVESTIGATIONAL AREA • eOUNOAflY OF HYDROGRflPHiC AREA ' BOUNDARY OF HYDROGRAPHIC UNIT BOUNDARY OF FEDERAL AND STATE LANDS IRRIGATED AGRICULTURAL EXPANSION I URBAN AND SUBURBAN AREAS EXPANSION y^//^///\ MILITARY RESERVATIONS 9-9 HYDROGRAPHIC UNIT NUMBER NOTE CHANGE IN LAND USE FOR SALTON SEA HYDROGRAPHIC UNIT IS 1950 TO 1958 STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY CHANGE IN LAND USE 1948 TO 1958 SCALE OF MILES HYDROGRAPHIC AREAS AND UNITS PORTION OF COLORADO DESERT AREA ■7 — 2 PORTION OF COACHELLA VALLEY UNIT 7" -3 PORTION OF SALTON SEA UNIT PORTION OF SOUTH COASTAL AREA 9-7 PORTION OF SAN JUAN CAPISTRANO UNIT 9—8 SANTA MARGARITA - SAN LUIS REV UNIT 9 — 9 SAN OIEGUITO - COTTONWOOD UNIT 9 -10 SAN DIEGO UNIT ^%^X--^ .is ^i&^ LOCUTION MAP I PLATE 5B LOCATION MAP LEGEND ' BOUNDARY OF IfyveSTIGATIONfiL AREA • BOUNDARY OF HYDROGRflPMIC AREA ' BOUNDARY OF HYDR06RAPHIC UNIT BOUNDARY OF FEDERAL AND STATE LANDS RRIGATEO AGRICULTURAL EXPANSION URBAN AND SUBURBAN AREAS EXPANSION MIXED INDUSTRIAL. COMMERCIAL, RESIDENTIAL, AND VACANT LANDS DETERMINED BY CITY OF SAN DIEGO (SEE TEXT! MILITARY RESERVATIONS MYDROGRAPHIC UNIT NUMBER NOTE CHANGE IN LAND USE FOR SALTON SEA MYDROGRAPHIC UNIT IS 1950 TO 1958 STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT SAN DIEGO COUNTY LAND AND WATER USE SURVEY CHANGE IN LAND USE 1948 TO 1958 SCALE OF MILES -r HYDROGRAPHIC AREAS AND UNITS PORTION OF COLORADO DESERT AREA 7 — 2 PORTION OF COACHELLA VALLEY UNIT 7 — 3 PORTION OF SALTON SEA UNIT PORTION OF SOUTH COASTAL AREA 9-7 PORTION OF SAN JUAN CAPISTRANO UNIT 9—8 SANTA MARGARITA - SAN LUIS REr UNIT 9 — 9 SAN DIE6UIT0 - COTTONWOOD UNIT 9-IO SAN DIEGO UNIT APPENDIX A DEFINITION OF TERMS APPENDIX A DEFINITION OF TERMS Annual - The 12-inonth period from January 1 of a given year throiigh December 31 of the same year, sometimes termed the "calendar year." iVpplied Water - Water 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. Applied water does not include direct pre- cipitation. Applied Water Requirement - The applied water needed to provide for all beneficial uses and for irrecoverable losses incidental to such uses. Applied water requirement excludes that portion of the requirement which is provided by precipitation. Aquifer - A geologic formation or structure sufficiently permeable to yield water to wells or springs. Average - An arithmetical average relating to a period other than a mean period. Confined Ground Water - A body of ground water immediately overlain by material sufficiently impervious to sever free hydraulic connection with overlying water, and acted upon by pressure caused by the difference in head between the intake or forebay area and the discharge area of the confined water body. Consumptive Use of Water - Water consumed by vegetative growth in trans- piration and building plant tissue, and water evaporated from adjacent soil, from water surface, and from foliage. It also refers to water similarly consumed and evaporated by urban and nonvegetative types of land use. A-1 Free Ground Water - A body of ground water not immediately overlain by impervious materials. Ground Water Overdraft - The annuaJ. net extraction of water from a ground water basin in excess of safe ground water yield. Irrigation Efficiency - The ratio of consumptive use of applied irriga- tion water to the total amount 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 water supply and climate over a long series of years. For purposes of the current investigation, the mean precipitation period embraces the 50 seasons from 1897-98 through 19^6-^7; the mean runoff period, the 53 seasons from 189^-95 through IShS-kj. Net Water Use - W^ter historically applied, or estimated to have been applied, which is consumptively utilized for beneficial purposes or irrecoverably lost. It does not include that portion of the applied water which is subject to possible reuse. Present - Land use and water supply conditions prevailing during the 1957-58 season. Safe Ground Water Yield - The average annual net amount of water that could be beneficieilly extracted from a ground water basin over an indefinitely long period of years, under a particular set of those physical conditions ai"fecting supply to, and disposal from, the ground water basin, without causing a net lowering of ground water levels during the period. A- 2 Seasonal - Any 12-month period other than the calendar year. Water Utilization - Water utilization includes all employments of water by nature or man, whether consumptive or nonconsuraptive, as well as irrecoverable losses of water incidental to such employment, and is synonymous with the term "water use." Water Requirement - The water needed to provide for all beneficial uses and for all irrecoverable losses incidental to such uses. Water requirement includes the portion supplied from direct precipitation. A- 3 APPENDIX B LAND USE IN HYDROLOGIC UNITS AND SUBUNTTS IN SAN DIEGO COUNTY AND A PORTION OF SOUTHWESTERN RIVERSIDE COUOTY IN 1958 n U O H 4J M 4-> ffl to l- tK -o D £-■ §aj t. 3 (D CO taC oj hJ 4-1 C' en I- > -H u dp a ■ 1 •r^ tw a) 3 a) > ■3 rH •H E » X > 0) to ^ M O V, M r-J >» o o +j bI eC rH tH +J o p c o tj _ c :3 e-. o o o o W OJ OJ CO § SI 8 ^ rnl CO '&| § 8| S §1 t) U Oi u *^ i-. qj tn t£ R rH r^ rH ri OOOOOOOOI oooooooo t^-d- OJ CO -H 88. O O O O O Ol OOOOOOOOI to to p. p. ^ a c ^^ g tn (I1 ^ V V u E ^ ^ a) *J O -H •rH H) < to a •H u Is 1 > S °l \8\ SI 8J 81 8 h| CO ) Ol Ol I ^ O 0| 0| o I if fc & U^ t- iH rn t- t-^ ir« oj i/\ o O Vii- OJ ai c^ I o 8^ 8. S n O n~ m (\\ OJ U\ if\ B-1 ■H > to H 3 -H O +J a 3SS 4) to -O C p o 3 41 p U3 K 0) 4> C r-j t, rH •H > 41 H d rH 3 -H 41 OJ 0) a) !!-' to 4> c +j a ■H > 41 m -H ^ ^r^ V u a • •^ re :> 0) 4^ ■PMC §>. 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M 5 +3 1 ■H O ^ *> d ■n « V ti u > B *j K IE u > d B-8 APPENDIX C LIST OF DISTRICTS, AREAS, AND ITNITS FOR WHICH INDIVIDUAL TABULATIONS OF 1958 LAND USES ARE AVAILABLE APPENDIX C LIST OF DISTRICTS, AREAS, AND UNITS FOR WHICH INDIVIDUAL TABULATIONS OF 1958 LAND USES ARE AVAILABLE Utilizing machine techniques that were developed for processing lata from this survey, individual tabu3.ations of 1958 land uses can be attained for most of the political and hydrologic subdivisions within the area of investigation. However, reasonable limitations do iiot permit all Df these individual tabulations to be published in this report. For those requiring more detailed information, this appendix Lists all districts, areas, and units for which 1958 land uses can be individually determined and tabulated by machine methods using data available in Department of Water Resources files. It should be noted that data were based on 1958 conditions, including boundaries, and have not been modified to reflect subsequent changes. COUNTY WATER DISTRICTS Pomerado County Water District San Marcas County Water District Tia Juana Valley County Water District INDIAN RESERVATIONS Barona Carapo Capitan Grande Coahuila Cioyapaipe Inaja C-1 INDIAN RESERVATIONS (continued) La JoUa La Posta Los Coyotes Manzanlta Mission Marongo Pala Pauma Pe change Rincon San Pasqual Sequan Viejas Yuima Cosmit San Ysabel Mesa Grande Rainona IRRIGATION DISTRICTS Helix Irrigation District Lakeside Irrigation District Ramona Irrigation District Rancho Santa Fe Irrigation District San Dieguito Irrigation District Santa Fe Irrigation District C-2 IRRIGATION DISTRICTS (continued) San Ysidro Irrigation District South Bay Irrigation District Spring Valley Irrigation District Vista Irrigation District MUNICIPALITIES Carlsbad Chula Vista Coronado El Cajon Encinitas Escondido Imperial Beach La Mesa National City Oceanside San Diego MUNICIPAL WATER DISTRICTS Bueno Colorado Municipal Water District Carlsbad Municipal Water District Otay Municipal Water District Poway Municipal Water District Rainbow Municipal Water District Ramona Municipal Water District Rlncon Del Diablo Municipal Water District Rio San Diego Municipal Water District C-3 MUNICIPAL WATER DISTRICTS (continued) Valley Center Muinicipal Water District Olivenhain Municipal Water District San Luis Rey Municipal Water District NATIONAL FORESTS, WILD AREAS Cleveland National Forest Aqua Tibia Wilderness Area PARKS State Parks Carlsbad State Park Cuyamaca Rancho State Park Montgomery Memorial State Park Palomar Mountain State Park * Silver Strand State Park Anza Borrego State Park Torrey Pines Beach County Pstrks Flinn Springs County Park City Parks Balboa Mission Bay Presidio Soledad Soledad Terrace Torrey Pines C-k PUBLIC UTILITY DISTRICTS Fallbrook Public Utility District Heber Public Utility District Crest Public Utility District SANITARY DISTRICTS Del Mar Sanitary District Fallbrook Saiiitary District Soledad Sanitary District Iii5)erial Beach Sanitary District Encinitas Sanitary District Green Acres Sanitary District SANITATION DISTRICTS Julian Sanitation District Lakeside Sanitation District Palm City Sanitation District Ramona Sanitation District Rancho Del Cainpo Sanitation District Randho Santa Fe Sanitation District San Ysidro Sanitation District Solana Beach Sanitation District Spring Valley Sanitation District Vista Sanitation District La Mesa Park Sanitation District Rolando Sanitation District Cardiff Sanitation District Poway Sanitation District C-5 SANITATION DISTRICTS Fletcher Hill Sanitation District Alpine Sanitation District WATER DISTRICTS Belfort Heights Water District Bonsall Heights Water District Los Posas Water District Moosa Water District OrchsLTd Water District Alpine Highlands Water District C-6