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San Diego Project
Region: Lower Colorado Basin Region
San Diego Project History (55 KB)
Yuma Area Office
San Diego Watershed
The San Diego Project consists of the First and Second San Diego Aqueducts. These two aqueducts, with two branch lines, make up the backbone of the San Diego County Water Authority system. The First Aqueduct consists of Pipelines 1 and 2, which extend from the Metropolitan Water District`s Colorado River Aqueduct near San Jacinto, California, to the city of San Diego`s San Vicente Reservoir, approximately 15 miles northeast of the city. Pipeline 1, designed by the Bureau of Reclamation, was constructed by the Navy Department to relieve the water supply emergency in San Diego County. Pipeline 2, roughly paralleling the first, was designed and constructed by the Bureau of Reclamation. The two pipelines share common tunnels and inverted siphons. They are operated as single units. The 12.5-mile Fallbrook-Ocean Branch originates from the First Aqueduct at Rainbow and extends to Morrow Reservoir. The La Mesa-Sweetwater Branch also originates from the First Aqueduct at Slaughterhouse Canyon, and extends through Lakeside and El Cajon to Sweetwater Reservoir. A number of connecting pipelines have been constructed to provide flexibility in operating the system. One pipeline runs from the Second Aqueduct at Twin Oaks Valley to refill the First Aqueduct north of Escondido with untreated water after the agencies to the north have utilized the original capacity of the aqueduct. An interconnection upstream from Twin Oaks Valley permits transfer of flows between Pipeline 3 and Pipeline 4. The Second Aqueduct consists of Pipelines 3 and 4. Although these pipelines are in common right-of-way for most of their length, they do not share any facilities south of Skinner Lake and are operated separately. Pipeline 3 extends from the Metropolitan Water District`s Colorado River Aqueduct near Hemet, in Riverside County, to San Diego`s Lower Otay Reservoir. Pipeline 4 terminates at San Diego`s Alvarado Treatment Plant near Lake Murray. The Metropolitan Water District (MWD), of which the San Diego County Water Authority (Authority) is a constituent member, constructed the northern 35 miles of the Second Aqueduct to a major delivery point of the Authority, located about 6 miles south of the Riverside-San Diego County line. The MWD owns and operates this section of the aqueduct. The Authority constructed the remaining 59 miles of the aqueduct, and owns and operates it.
Over a period of years, the city of San Diego developed a domestic water supply by acquisition or construction of a number of dams. To obtain a dependable, uniform supply of water, the city contracted for storage in Lake Mead, the reservoir formed by Hoover Dam, for a quantity of water not to exceed 112,000 acre-feet annually. On October 2, 1934, the city entered into a contract with the Bureau of Reclamation. This contract provided for the city`s participation in construction of Imperial Dam and the All-American Canal under the Boulder Canyon Project Act. Under that contract, a capacity of 155 cubic feet per second in the All-American Canal was provided for the city. On November 29, 1944, under a Presidential directive, Reclamation completed plans and specifications for a one-half capacity aqueduct for the MWD connection; the Navy`s Bureau of Yards and Docks was directed to perform the construction. In addition, Reclamation, with the Navy Department cooperating, was asked to construct additional works needed to bring the aqueduct to its ultimate capacity for carrying San Diego`s allotted water. A contract dated October 4, 1946, changed the point of delivery of Colorado River water to which San Diego had contractual rights from Imperial Dam to Parker Dam. Under a contract dated October 4, 1946, San Diego assigned its Colorado River water rights to the MWD. On December 17, 1947, the San Diego County Water Authority was formally annexed to the MWD of Southern California, thereby becoming entitled to Colorado River water from the MWD system for distribution to the Authority`s member agencies in San Diego County. When construction was completed in 1947 and Pipeline 1 of the First Aqueduct was placed in operation, the San Diego County Water Authority recommended that the aqueduct immediately be enlarged to full capacity to safeguard the area from critical water shortages. Reclamation was requested to make the necessary survey and reports. In January 1951, a report was submitted proposing the enlargement of the aqueduct to full capacity by the addition of Pipeline 2 to the conduit of the same capacity as that previously designed and constructed. The Authority selected the parallel location as recommended for Pipeline 2. In 1956, the California State Legislature appropriated funds for a study to determine the most practical route by which northern California water might be brought into San Diego County. The report recommended that a canal section, about 30 miles long, with a capacity of 1,000 cubic feet per second, be constructed as the northerly portion of the aqueduct, beginning at the west portal of the San Jacinto Tunnel of MWD`s Colorado River Aqueduct and extending to the vicinity of Auld Valley in Riverside County. The remainder of the proposed aqueduct, beginning at the end of the canal, was recommended to have a capacity ranging from 432 cubic feet per second at the upper end to 98 cubic feet per second at the terminus at Otay Reservoir. In January 1957, the Authority adopted the route of the Second San Diego Aqueduct, as recommended by the State. The State of California commenced construction of the Second San Diego County Feeder Line, which is the northerly portion of the Second San Diego Aqueduct, from the West Portal of the San Jacinto Tunnel to a delivery point and connection to the Authority`s system, located about 6 miles south of the Riverside-San Diego County line. The district adopted a canal capacity of 500 cubic feet per second instead of the 1,000 cubic feet per second recommended by the State and a pipeline capacity of 250 cubic feet per second instead of the 432 cubic feet per second recommended by the State. It was recognized in the 1950`s that additional water supply sources for the Southern California area would be required by the early 1970`s. On November 4, 1960, the MWD entered into a contract with the State of California for 1,500,000 acre-feet annually from the State Water Project. As a result of the 1963 United States Supreme Court decision in the case of Arizona v. California, MWD was subject to the loss of about half its 1,212,000 acre-feet entitlement from the Colorado River. In view of this condition, the MWD-State of California contract was amended to increase MWD entitlement to State water to 2,011,500 acre-feet per year. The California Aqueduct, the key feature of the State Water Project, was dedicated on May 18, 1973. The terminal storage reservoir of the California Aqueduct is Lake Parris.
Construction of Pipeline 1 of the First Aqueduct by the Navy began in 1945 and was completed in 1947. Pipeline 2 was constructed by the Bureau of Reclamation from 1952-54. Construction of the Second Aqueduct began in 1957. The MWD section of Pipeline 3 was completed in May 1960, and the Authority`s section in November 1960. Construction of the MWD section of Pipeline 4 of the Second Aqueduct started in 1968 and was completed in 1971. The Authority started construction of its section of Pipeline 4 in 1969. Construction of the first three phases of the pipeline was completed in 1973, and the fourth phase was completed in 1979. The Colorado River Aqueduct supplies more than 90 percent of all the water used in San Diego County. Over 98 percent of the population of San Diego County, which exceeds 1.6 million people, live within the Authority service area. The total water supply of the Authority comes through the facilities of the First and Second San Diego Aqueducts. The system provides a means for importing water for municipal, domestic, and other beneficial uses. During Reclamation`s first forty years, the bureau`s engineers forged a reputation for manipulating rock and water in places that will never see a streetlamp. Much of their work is conducted far away from population centers, and occasionally, their efforts stimulated the growth of western metropolises like Los Angeles, Phoenix, and Las Vegas. Until the 1940s, Reclamation had never been called upon to directly assist a city in search of water. However in 1944, a struggle on a crucial World War II home front pulled Reclamation into an alliance with other federal agencies and branches of the military to divert an urban disaster. The epicenter of this crisis was the heretofore slow-paced community of San Diego, California. On the eve of United States entry into the war, an unprecedented influx of military personnel and civilian workers threatened to consume all of metropolitan San Diego`s water supply in a matter of a few months. A military-industrial dilemma had to be resolved with a federally devised solution. The force of executive action and the spirit of wartime efficiency caused Reclamation to design a pipeline to carry Colorado River water to a thirsty San Diego. The San Diego Aqueduct runs 71 miles from the San Jacinto Tunnel at the Colorado River Aqueduct south to the terminal of the San Vicente Reservoir, located 15 miles northeast of the city of San Diego. The tunnel and reservoir provide the San Diego Aqueduct with its official name, the San Jacinto-San Vicente Project. Oblivious to topography, the pipeline, or `barrel,` in engineering parlance, makes its way across the variances of Southern California. From the San Jacinto tunnel, the barrel extends southwest over rolling countryside along the first third of its trip until it reaches the Temecula River. Two miles south of the river, the Aqueduct crosses the summit of Rainbow Pass and runs alongside U.S. Highway 395. Across the next thirteen miles, the pipeline passes through four tunnels and over rocky ground. Fifty-eight miles into its journey, the aqueduct travels east of the town of Escondido, passing vineyards, citrus and avocado groves on to the San Dieguito River. Across the river, the pipeline runs southeast from Poway Valley into the inlet portal of the Poway Tunnel. In the final four miles, the barrel enters two tunnels before delivery at the San Vicente Reservoir. San Diego County provides almost everything nature offers, except enough water to serve a population of millions. Proceeding inland from the Pacific Coast, the county rises from coastal plain to inland valleys to the Laguna Mountain range and back down to desert valleys. The climate is mild to semi-arid with an average temperature of 63 degrees. San Diego County covers some 4,200 square miles with two-thirds of the county`s 2.3 million people living west of the mountains. Since weather records were first kept in 1851, climatologists tracked dry periods lasting from six to 21 years and wet cycles averaging 11 years. In rainy years, precipitation falls from December to April. Annual precipitation averages about 10 inches along the coast, but is four to five times greater over the Lagunas. Run-off from the mountains has always been erratic, and San Diegans realized early that they not could depend on it as a sole source of water.(1) From the arrival of the Spanish padres up to the present, San Diego`s struggle to keep and hold water has progressively intensified. In 1769, a contingent led by Father Junipero Serra trekked 1,800 miles northward from Mexico to establish California`s first European settlement, San Diego de Alcala. Four years later, work started on the first irrigation and domestic water supply system in the American West. Under the watchful Serra and other Franciscan brothers, Indian work gangs dug canals to irrigate mission vineyards and vegetable plots. The next step was construction of a dam. Preserved as a historical landmark, the Old Mission Dam, is made of jagged rock and brick held together with mortar. In 1810, San Diego River water held by the dam was flowing in tile lined conduits from the upper end of Mission Gorge to the valley lands in the vicinity of the San Diego Mission six miles away. Soon, Mexican ranchers replaced the missionaries and were then in their turn superseded by stragglers from the San Francisco gold rush. In the mid-19th Century, San Diego`s water supply came from the annual output of 60,000 acre-feet of underground water or water diverted from foothills streams. The arrival of the California Southern Railway brought the next generation of settlers. The enterprising newcomers quickly dammed the coastal streams surrounding San Diego to provide domestic water to the city and an irrigation supply to nearby agricultural areas, and many of these privately funded dams are still in use today. The county`s streams from north to south are: Santa Margarita, San Luis Rey, San Dieguito, San Diego, Otay, and Tia Juana. In 1888, the city`s first diversion project brought water from the headwaters of the San Diego River 35 miles down to the city. A trestle flume carried the water over gullies and ravines, but it often leaked or had sections blown over by the wind. Despite its primitive technology, parts of the flume were sturdy enough to remain in service until 1957.(2) Droughts in the late 1880s, and from 1897 to 1904, thinned San Diego`s population from 40,000 people down to 17,700 by 1900. The city`s climate and tranquility still attracted outsiders, and by 1920, the population was back up to 74,361. During this period, the necessity of obtaining water from outside the county dawned on San Diego`s civic leaders, and they looked toward the unpredictable flow of the Colorado River to provide the foundation of the city`s future stability. In 1926, the California Division of Water Resources agreed to give the city the right to appropriate 155 cubic feet per second (cfs) of water from the river. On June 25, 1929, President Herbert Hoover approved the Boulder Canyon Project Act, and two years later, the City and County of San Diego completed a deal with six other Southern California water regulatory bodies dividing California`s share of the river.(3) In the 1930s, the City and County of San Diego filed petitions with the Secretary of the Interior to receive 250,000 acre-feet of storage capacity from Lake Mead and the delivery of 112,000 acre-feet of water annually through the All-American Canal system. In 1936, the city launched a study to determine the feasibility of constructing a branch aqueduct to serve San Diego. The final report of February 1937 recommended economy. San Diego should develop its local resources, and when additional water was needed, build its own aqueduct and import water from the All-American Canal. San Diego could take its share of Colorado River water from the canal 176 miles to the east, lifted by pumps over the mountains, and dispersed to the city`s reservoirs. The other option suggested by the report would bring river water captured at Lake Havasu 215 miles away and transferred to the Metropolitan Water District (MWD) of Southern California. The primary purpose of the MWD was to provide Colorado River water to metropolitan Los Angeles. As Los Angeles grew, so did the MWD, and its influence was felt from Pasadena to the Mexican border. Delivery of water through MWD to San Diego would come by a separate gravity-flow pipeline. Included in project costs were fees to join the MWD plus other expenses. The All-American Canal route was favored among many San Diegans, because it allowed the city autonomy from sharing Colorado River water with Los Angeles and the rest of Southern California. Engineers and city officials felt there was no reason why the city would not continue to steadily grow and eventually develop a water system to solely serve San Diego.(4) The war in Europe blew San Diego`s vision of measured growth sky-high. As the military and industry invaded the city, local legislators panicked. On May 28 and 29, 1943, in order to determine the most feasible means of obtaining Colorado River water, the City and County signed contracts with Reclamation to survey routes. The first survey would be the MWD Colorado River Aqueduct at the San Jacinto tunnel. A separate investigation would examine the favorite choice of San Diego`s landowners, merchants, and developers, the All-American Canal.(5) Concurrent with the surveys, the San Diego County Water Authority (SDCWA) organized on June 9, 1944, for the purpose of delivering Colorado River water to San Diego County. The original nine members of the SDCWA comprised five cities (San Diego, Chula Vista, Coronado, National City, and Oceanside), three irrigation districts (Lakeside, Helix and Ramona), and one public utility district (Fallbrook). Looming over the surveys and participants was a dry 1944 which broke a five-year string of above average annual precipitation. In September, Reclamation`s report on the MWD-San Jacinto connection revealed additional troubling news. Engineer R.B. Ward emphasized the city was teetering toward drought, `In June 1944, it was thought that the City of San Diego had sufficient water in storage to supply its users through the year 1947. During the subsequent three months, however, the volume of use increased to such an extent the supply maybe depleted by July 1947.` In Ward`s opinion, `plans for importing a supplemental supply must be formulated much sooner than was formerly anticipated.`(6) In the months before December 1941, San Diego was on the cutting edge of war production as government contracts, military build-up and factory jobs made the city hum. A reporter for a national magazine wrote pre-war San Diego was a `quiet, slow moving town,` whose principal industry was `tourists.` Another publication said the city of a little over 200,000 was `indolent,` and local business subsisted on `expenditures made by the United States Navy and by the residents who were retired from middle-class families.` Because of war contracts, San Diego became the quintessential boom town of the twentieth century. In the nineteenth century, other California cities like San Francisco and Los Angeles were founded on gold and oil rushes. San Diego`s boom was fueled with federal and corporate dollars. In 1943, City Manager Walter Cooper said war `revolutionized` San Diego, and its effect `is not fixed or static, but it is a constantly changing factor in the life of the city.` In 1940, the city`s population was 202,000. Four years later, it ballooned to 510,000 with 380,000 civilians and 130,000 military people. War brides, servicemen, pilots and factory workers intermingled in the few downtown blocks holding the city`s restaurants, tattoo parlors, burlesque houses, and saloons. Movie theaters were open all hours, dance halls swung until late. In the summer of 1944, San Diego`s role as ship and aircraft builder was a vital element in the America`s arsenal, but the city was under attack. Not from enemy artillery or bombs, but from nature`s caprice and humanity`s excess.(7) Only a few times in Reclamation`s history has there been as much urgency expended from the highest levels of government to begin a project as there was in San Diego. Normally obsessed with the Central Valley Project, California Senator Sheridan Downey finished reading Reclamation`s San Diego report with much anxiety. In a letter dated September 25, 1944, Downey begged President Franklin D. Roosevelt to authorize the federal government to step into the San Diego situation, `In the event history repeats itself, as is most probable, and years of little or no runoff occur in the San Diego watershed, this city and all the important naval and military establishments in the locality will be without water early in 1947.`(8) In eight days time, Roosevelt appointed a committee to study San Diego`s water problems. William E. Warne, acting commissioner of Reclamation, served as chair of an interdepartmental committee comprising representatives from the Departments of Navy and War, the Federal Works Agency, and the San Diego County Water Authority. On Oct. 3, Roosevelt wrote back to Downey, agreeing it was imperative the aqueduct be built, `Because of the importance of the San Diego area from a naval and military standpoint and the need for protection of its civilian population, this situation is of national concern.`(9) In the course of their research, the committee determined the city of San Diego could safely use 30,000 acre-feet annually. If the population continued to grow, the city would have to supply 52,000 acre-feet in a year. A breakdown of total water use proved the Navy consumed 21.6 percent of city water, followed by the Army, federal housing, and war industries. Military and military-related organizations may have occupied only 10 percent of San Diego`s land area, but they used 40.3 percent of municipal water. Civilians had to make due on the remaining 59.7 percent. Two months later, following Reclamation`s suggestion, the committee recommended immediate construction of a connection at San Jacinto with the Colorado River Aqueduct. The committee rejected the All-American Canal route, because construction required extra equipment to lift the water and would take three years -- a year longer -- to build than the San Jacinto-San Vicente proposal. The War and Navy Department along with the Federal Works Agency would bear the entire cost. On November 29, 1944, Roosevelt approved the report and instructed Reclamation to complete the designs and the Navy Bureau of Yards and Docks to begin construction.(10) In January and February 1945, 42 Reclamation employees from regional offices in Arizona, California, Colorado, New Mexico, and Utah were loaned to the San Diego Project. They stayed an average of two months in San Diego as they performed survey and other kinds of fieldwork. All of Reclamation`s drawings, specifications, and surveys were complete by early June of 1945. On March 3, the Director of the War Mobilization and Reconversion Board wrote to the Secretary of the Navy recommending the aqueduct project be delayed for a year due to material and manpower shortages. The chairman of the Authority, Fred A. Heilbron, flew to Washington to remind officials, in a series of conferences of the importance of San Diego`s military-industrial muscle in the war effort. He also pointed out the city was mired in another drought cycle. Heilbron`s arguments swayed the bureaucracy and the project was back on track. Later in the autumn of 1945, the Navy and the city of San Diego agreed to continue construction of the aqueduct by the Navy and lease of the pipeline to the city.(11) Six contractors -- five from California and one from New York State -- were charged with building the pipeline which was divided into seven schedules for purposes of construction. The contract ran from September 1945 to May 1946. The contractor`s work schedules were divided between one contract for building diversion works and a regulating reservoir with connecting pipe lines, two for tunnels, three for the concrete pipe line and one schedule for the steel pipe siphons. The schedules were numbered in sequence to conform with the completion of field surveys and the drafting of drawings and specifications. Ground breaking began on September 12, less than two weeks after the Japanese signed surrender terms on the deck of the battleship Missouri.(12) Reclamation`s original designs provided for the use of precast concrete pipe with an ultimate capacity of 165 cfs. Seven tunnels and the first two miles of the barrel and certain limited access sections were built to full design capacity. The remaining 61 miles were built to carry 85 cfs, in case San Diego needed the extra water in the future. Except for one and three-quarters miles of steel 48-inch pipe, the aqueduct used reinforced concrete pipe varying from 48 to 96 inches in diameter.(13) In November 1945, contractors had difficulty in finding qualified tunnel workers, despite the return home of the first wave of servicemen back from the war. Recruits went as far north as Fresno to find unskilled laborers to work for 87.5 cents an hour and equipment operators to work for $1.75 an hour. Six months later, in the summer of 1946, as many as 850 men were involved in all aspects of construction. Much of the construction landscape was either rural or rugged. In the central and southern construction sites there were no telephone lines connected with each contractor`s field office. Workmen used two-way radios so that repair crews, assistance, and spare parts arrived on the scene faster, and contractors were able to dispatch trucks and bulldozers to required locations. Major external delays included the 1946 strikes by the coal and steel industries holding up allocations and shipments of steel which delayed construction for three months. Originally the project was scheduled to last 15 months, but stoppages pushed completion time to 25 months.(14) The mountains provided the stage for the project`s most demanding work as drillers bored seven tunnels allowing the pipeline to pass. The names of the tunnels in order from San Jacinto Tunnel are: Rainbow, Lilac, Red Mountain, Oat Hills, Poway, Fire Hill and San Vicente. Excavations range from 500 feet in the Lilac Tunnel to 5,700 feet in the Fire Hill Tunnel. The diameter of each tunnel is six feet. The 4.4 miles of concrete-lined tunnels comprise 14 percent of the total length of the aqueduct.(15) As construction continued, San Diego`s dream of private access to the Colorado had to be relinquished. The city surrendered its Colorado River water filing to the SDCWA which in turn transferred these rights to the powerful Metropolitan Water District of Southern California. On December 17, 1946, the SDCWA was annexed to the MWD. The shotgun marriage of the Authority with the Los Angeles-based MWD is a key element in the creation of modern San Diego. The once sleepy seaport joined the reality of urban Southern California sprawl.(16) At 2 o`clock on the morning of November 26, 1947, the first Colorado River water reached the San Vicente aqueduct. The final cost of $14.1 million dollars was a small price to pay in comparison to what might have happened if the city had gone dry. An estimated of the first year`s flow out of the barrel was 66,700 acre-feet. The Authority said without Colorado River water, all City of San Diego reservoirs would have been empty by September of 1949.(17) The December 11, 1947, aqueduct dedication caused a brief celebration in the city. A Reclamation Engineer later congratulated all the parties involved, `The job is an outstanding example of the ability of Federal and State agencies to work together to accomplish a mutual objective.` Ewart W. Goodwin, chairman of the San Diego-Colorado River Association, publicly thanked Reclamation, the Navy and the federal government for `saving` San Diego. Reclamation`s survey work and engineering experience brought the project in very close to the original projected cost. If the aqueduct had not been completed in time, San Diegans faced rationing. Now with the barrel completed, engineers estimated, and locals hoped, the aqueduct would keep San Diego in water for the next 20 to 30 years.(18)
The MWD of Southern California diverts water from the Colorado River at Lake Havasu and conveys it through the Colorado River Aqueduct to its terminus at Lake Mathews. Reach Five of the MWD Inland Feeder System comprises the First and Second San Diego Aqueducts. The four San Diego pipelines of the two aqueducts have a combined capacity of 826 cubic feet per second. Included in this reach of the inland feeder system is Lake Skinner, a regulating and storage reservoir, and the Robert A. Skinner Filtration Plant. The MWD`s San Diego Canal receives California State Water Project water from the Casa Loma Canal. Flow in the San Diego Canal is normally diverted into Lake Skinner and then routed to San Diego Pipelines 3 and 4 or into the Robert A. Skinner Filtration Plant through the outlet works. Water from Lake Skinner is routed directly into the filtration plant; treated water from the plant is diverted into San Diego Pipeline 3. Untreated water from the lake is diverted directly into Pipeline 4 after passing through the Auld Valley Control Structure. This structure controls the flow of water either from Lake Skinner, or directly from the San Diego Canal through the reservoir bypass pipeline. Lake Skinner has a total capacity of 44,000 acre-feet, and a maximum elevation of 1,479.0 feet. In 1977, the Skinner Filtration Plant, located near Lake Skinner, had a capacity of 150 million gallons per day. An extension of the plant in 1979 increased the capacity to 240 million gallons per day. A further expansion, completed in 1980, raised the capacity to 340 million gallons per day. The San Jacinto Regulating Reservoir of the First San Diego Aqueduct was removed from service on October 24, 1974, because of a requirement of the State of California Division of Safety of Dams. Water for Pipeline 2 was subsequently taken from Pipeline 1 at Rainbow Pass and Pipeline 1 receives water directly from the San Diego Canal at their crossing, near San Jacinto. No storage facilities are owned or operated by the Authority. However, it has contractual rights to store up to 40,000 acre-feet in San Diego`s San Vicente Reservoir, terminus of the First Aqueduct. The Authority also has an agreement with the city of San Diego which permits storage of up to 2,500 acre-feet in Lower Otay Reservoir, terminus of Pipeline 3. Lake Jennings is used to store as much as 2,000 acre-feet, under terms of an agreement with Helix Water District. The Authority has agreements to store up to 1,800 acre-feet in the city of Escondido`s Dixon Reservoir and 3,855 acre-feet in the Sweetwater Reservoir of the California American Water Company. The First San Diego Aqueduct is about 70 miles long and water flows by gravity from an intake at an elevation of 1500 ft to the San Vicente Reservoir at an elevation of 760 ft. The first two miles, the tunnels, and certain other sections not readily accessible were built to full capacity during construction of the first pipeline. The remaining sections, approximately 60 miles, compose a double pipeline. The separate pipelines are precast concrete pipe. The design capacity of the First San Diego Aqueduct is 196 cubic feet per second. There are seven tunnels ranging in length from 500 to 5,700 feet. These tunnels, together with the diversion line to the regulating reservoir and the short reaches of full capacity pipeline, total about 14 percent of the length of the aqueduct. The 94-mile-long Second San Diego Aqueduct flows by gravity from MWD`s takeoff point to the Otay Reservoir through Pipelines 3 and 4. Pipeline 3 consists of a 500-cubic-foot-per-second, 16-mile long canal. The remaining section, from Lake Skinner to its terminus, is composed of a combination of prestressed concrete pipe and steel pipe, and has an initial capacity of 250 cubic feet per second. At the Otay Reservoir, the pipeline`s capacity is 144 cubic feet per second. Pipeline 4 is composed of 99-inch-diameter prestressed concrete pipe with an initial capacity of 380 cubic feet per second. The San Diego County Water Authority is responsible for the operation and maintenance of the First and Second Aqueducts south from MWD`s point of delivery. MWD is responsible for the operation and maintenance of the aqueducts north of the delivery point. On December 3, 1997, title for the First Aqueduct (Pipelines 1 and 2) was transferred from the United States to the San Diego County Water Authority. The Authority subsequently transferred title to that portion of the aqueduct north of the Metropolitan Water District delivery point to the Metropolitan Water District.
Loving, M.W. `San Jacinto-San Vicente Aqueduct: San Diego Project, California, Second Pipeline,` Glenville, Il.: 1953. U.S., Department of Commerce, Bureau of Census, 1990 Census of Population and Housing Summary, California, Tape File 3A, Washington, D.C.: 1991.
ContactTitle: Public Affairs Officer
Organization: Lower Colorado Regional Office
Address: PO Box 61470
City: Boulder City, NV 89006-1470
OwnerTitle: Public Affairs Officer
Organization: Commissioner`s Office
Address: 1849 C Street NW
City: Washington, DC 20240
ContactOrganization: San Diego County Water Authority
Address: 4677 Overland Ave
City: San Diego, CA 92123