California State Water Project
The California State Water Project, commonly known as the SWP, is a state water management project in the U.S. state of California under the supervision of the California Department of Water Resources. The SWP is one of the largest public water and power utilities in the world, providing drinking water for more than 27 million people and generating an average of 6,500 GWh of hydroelectricity annually. However, as it is the largest single consumer of power in the state itself, it has a net usage of 5,100 GWh.
The SWP collects water from rivers in Northern California and redistributes it to the water-scarce but populous cities through a network of aqueducts, pumping stations and power plants. About 70% of the water provided by the project is used for urban areas and industry in Southern California and the San Francisco Bay Area, and 30% is used for irrigation in the Central Valley. To reach Southern California, the water must be pumped over the Tehachapi Mountains, with at the Edmonston Pumping Plant alone, the highest single water lift in the world. The SWP shares many facilities with the federal Central Valley Project, which primarily serves agricultural users. Water can be interchanged between SWP and CVP canals as needed to meet peak requirements for project constituents. The SWP provides estimated annual benefits of $400 billion to California's economy.
Since its inception in 1960, the SWP has required the construction of 21 dams and more than of canals, pipelines and tunnels, although these constitute only a fraction of the facilities originally proposed. As a result, the project has delivered an average of only annually, as compared to total entitlements of. Environmental concerns caused by the dry-season removal of water from the Sacramento–San Joaquin River Delta, a sensitive estuary region, have often led to further reductions in water delivery. Work continues today to expand the SWP's water delivery capacity while finding solutions for the environmental impacts of water diversion.
History
The original purpose of the project was to provide water for arid Southern California, whose local water resources and share of the Colorado River were insufficient to sustain the region's growth. The SWP was rooted in two proposals. The United Western Investigation of 1951, a study by the U.S. Bureau of Reclamation, assessed the feasibility of interbasin water transfers in the Western United States. In California, this plan contemplated the construction of dams on rivers draining to California's North Coast – the wild and undammed Klamath, Eel, Mad and Smith River systems – and tunnels to carry the impounded water to the Sacramento River system, where it could be diverted southwards. In the same year, State Engineer A.D. Edmonston proposed the Feather River Project, which proposed the damming of the Feather River, a tributary of the Sacramento River, for the same purpose. The Feather River was much more accessible than the North Coast rivers, but did not have nearly as much water. Under both of the plans, a series of canals and pumps would carry the water south through the Central Valley to the foot of the Tehachapi Mountains, where it would pass through the Tehachapi Tunnel to reach Southern California.Calls for a comprehensive statewide water management system led to the creation of the California Department of Water Resources in 1956. The following year, the preliminary studies were compiled into the extensive California Water Plan, or Bulletin No. 3. The project was intended for "the control, protection, conservation, distribution, and utilization of the waters of California, to meet present and future needs for all beneficial uses and purposes in all areas of the state to the maximum feasible extent." California governor Pat Brown would later say it was to "correct an accident of people and geography".
The diversion of the North Coast rivers was abandoned in the plan's early stages after strong opposition from locals and concerns about the potential impact on the salmon in North Coast rivers. The California Water Plan would have to go ahead with the development of the Feather River alone, as proposed by Edmonston. The Burns-Porter Act of 1959 provided $1.75 billion of initial funding through a bond measure. Construction on Stage I of the project, which would deliver the first of water, began in 1960. Northern Californians opposed the measure as a boondoggle and an attempt to steal their water resources. In fact, the city of Los Angeles – which was to be one of the principal beneficiaries – also opposed the project; locals saw it as a ploy by politicians in the other Colorado River basin states to get Los Angeles to relinquish its share of the Colorado River. Historians largely attribute the success of the Burns-Porter Act and the State Water Project to major agribusiness lobbying, particularly by J.G. Boswell II of the J.G. Boswell cotton company. The bond was passed on an extremely narrow margin of 174,000 out of 5.8 million ballots cast. In 1966, the Metropolitan Water District passed Proposition W, a Southern California property tax bond to connect its regional water system to the new state project.
In 1961, ground was broken on Oroville Dam, and in 1963, work began on the California Aqueduct and San Luis Reservoir. The first deliveries to the Bay Area were made in 1962, and water reached the San Joaquin Valley by 1968. Due to concerns over the fault-ridden geography of the Tehachapi Mountains, the tunnel plan was scrapped; the water would have to be pumped over the mountains' crest. In 1973, the pumps and the East and West branches of the aqueduct were completed, and the first water was delivered to Southern California. A Peripheral Canal, which would have carried SWP water around the vulnerable and ecologically sensitive Sacramento–San Joaquin River Delta, was rejected in 1982 due to environmental concerns. The Coastal Branch, which delivers water to coastal central California, was completed in 1997.
Project description
Feather River facilities
The Feather River, a tributary of the Sacramento River, provides the primary watershed for the State Water Project. Runoff from the Feather River headwaters is captured in Antelope, Frenchman, and Davis reservoirs, which impound tributaries of the North and Middle forks of the Feather River. Collectively referred to as the Upper Feather River Lakes, these three reservoirs provide a combined storage capacity of about.Water released from the Upper Feather River system flows into Lake Oroville, which is formed by the Oroville Dam several miles above the city of Oroville. At, Oroville is the tallest dam in the United States; by volume it is the largest dam in California. Authorized by an emergency flood control measure in 1957, Oroville Dam was built between 1961 and 1967 with the reservoir filling for the first time in 1968.
Lake Oroville has a capacity to store approximately of water which accounts for 61 percent of the SWP's total system storage capacity, and is the single most important reservoir of the project.
Water stored in Lake Oroville is released through the 819 MW Edward Hyatt pumped-storage powerplant and two other hydroelectric plants downstream of Oroville Dam, which together make up the Oroville–Thermalito Complex. The Thermalito Forebay and Afterbay support the 120 MW Thermalito Pumping-Generating Plant, and the Thermalito Diversion Dam supports a smaller 3.3 MW powerplant. The entire system generates approximately 2.2 billion kilowatt hours per year, making up about a third of the total power generated by SWP facilities.
Delta facilities
From Oroville, a regulated water flow travels down the Feather and Sacramento Rivers to the Sacramento–San Joaquin River Delta. North of Rio Vista, about per year is pumped into the North Bay Aqueduct, completed in 1988. The aqueduct delivers water to clients in Napa and Solano counties.Image:Del Valle Regional Park Panorama.jpg|thumb|left|Lake Del Valle stores SWP water diverted through the South Bay Aqueduct for use in the San Francisco Bay Area.
The vast majority of the SWP water is drawn through the Delta's complex estuary system into the Clifton Court Forebay, located northwest of Tracy on the southern end of the Delta. Here, the Harvey O. Banks Pumping Plant lifts water into the California Aqueduct. Completed in 1963, the eleven pump units can lift up to of water – upgraded in 1986 from its original capacity of across seven units.
From here the water flows briefly south along the California Aqueduct to the Bethany Reservoir. The South Bay Pumping Plant supplies the South Bay Aqueduct, which has delivered water west to Alameda County since 1962 and Santa Clara County since 1965. The aqueduct carries a maximum of per year. Up to of this water can be stored in Lake Del Valle, an offstream reservoir located near Livermore.
California Aqueduct
South of the Bay Area diversions, the bulk of the SWP water – ranging from per year – travels south along the western flank of the San Joaquin Valley through the California Aqueduct. The main section of the aqueduct stretches for ; it is composed mainly of concrete-lined canals but also includes of tunnels, of pipelines and of siphons. The aqueduct reaches a maximum width of and a maximum depth of ; some parts of the channel are capable of delivering more than. The section of the aqueduct that runs through the San Joaquin Valley includes multiple turnouts where water is released to irrigate roughly of land on the west side of the valley.Image:CaAqueductPumping wb.jpg|thumb|right|Dos Amigos Pumping Plant on the California Aqueduct
The aqueduct enters the O'Neill Forebay reservoir west of Volta, where water can be pumped into a giant offstream storage facility, San Luis Reservoir, formed by the nearby B.F. Sisk Dam. San Luis Reservoir is shared by the SWP and the federal Central Valley Project; here water can be switched between the California Aqueduct and Delta-Mendota Canal to cope with fluctuating demands. The SWP has a 50 percent share of the of storage available in San Luis Reservoir.
South of the San Luis Reservoir complex, the aqueduct steadily gains elevation through a series of massive pumping plants. Dos Amigos Pumping Plant is located shortly south of San Luis, lifting the water. Near Kettleman City, the Coastal Branch splits off from the main California Aqueduct. Buena Vista, Teerink and Chrisman Pumping Plants are located on the main aqueduct near the southern end of the San Joaquin Valley near Bakersfield. The aqueduct then reaches A.D. Edmonston Pumping Plant, which lifts the water over the Tehachapi Mountains that separate the San Joaquin Valley from Southern California. It is the highest pump-lift in the SWP, with a capacity of across fourteen units. Initial construction of Edmonston was completed in 1974, with the last three units installed in the 1980s.
Once reaching the crest of the Tehachapis, the aqueduct runs through a series of tunnels to the Tehachapi Afterbay, where its flow is partitioned between West and East Branches.