California State Water Project

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California State Water Project
Map showing major features of the project (SWP reservoirs in blue, SWP/CVP reservoirs in purple, and other connected facilities in light blue)
General statistics
Storage dams10
Additional dams4 (reregulation)
4 (hydroelectric)
2 (flood control)
1 (mitigation/conservation)
Power plants5 conventional
3 pumped-storage
Canals701.5 miles (1,129.0 km)
Storage capacity5,746,790 acre-feet (7.08856×109 m3)
Annual water yield2,400,000 acre-feet (3.0×109 m3)[1]
Land irrigated750,000 acres (300,000 ha)
Power plant capacity2,991.7 MW
Annual generation6500 GWh
Annual consumption11500 GWh
Constituencies servedGreater Los Angeles Area
Greater San Diego
Inland Empire
San Francisco Bay Area
North Bay
Santa Clara Valley
South Bay
Central Coast
San Joaquin Valley

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.[2][3][4]

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.[5] To reach Southern California, the water must be pumped 2,882 feet (878 m) over the Tehachapi Mountains, with 1,926 feet (587 m) at the Edmonston Pumping Plant alone, the highest single water lift in the world.[6] The SWP shares many facilities with the federal Central Valley Project (CVP), 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.[7]

Since its inception in 1960, the SWP has required the construction of 21 dams and more than 700 miles (1,100 km) of canals, pipelines and tunnels,[8] although these constitute only a fraction of the facilities originally proposed. As a result, the project has only delivered an average of 2.4 million acre-feet (3.0 km3) annually, as compared to total entitlements of 4.23 million acre-feet (5.22 km3). 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.


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.[9] 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.[10] 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.[11]

Several primary beneficiaries of the SWP, from left to right: Los Angeles, the San Joaquin Valley, and the Santa Clara Valley (South Bay Area)

Calls for a comprehensive statewide water management system (complementing the extensive, but primarily irrigation-based Central Valley Project) 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."[12] California governor Pat Brown would later say it was to "correct an accident of people and geography".[13]

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 2.23 million acre-feet (2.75 km3) of water, began in 1960.[14] Northern Californians opposed the measure as a boondoggle and an attempt to steal their water resources.[15] 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.[16][17][18] The bond was passed on an extremely narrow margin of 174,000 out of 5.8 million ballots cast.[19]

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' 3,500-foot (1,100 m) 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.[20] 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.[15]

Project description[edit]

Feather River facilities[edit]

Oroville Dam and Lake Oroville on the Feather River
In May 2021, water levels of Lake Oroville dropped significantly, exposing much of the banks as California headed into another drought year. The Edward Hyatt Power Plant was forced to shut down due to low water levels later in the summer.[21]

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 162,000 acre-feet (0.200 km3).[22]

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.[23] At 770 feet (230 m), Oroville is the tallest dam in the United States;[24] by volume it is the largest dam in California. Authorized by an emergency flood control measure in 1957,[25] Oroville Dam was built between 1961 and 1967 with the reservoir filling for the first time in 1968.[26] Lake Oroville has a capacity to store approximately 3.54 million acre-feet (4.37 km3) 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.[24]

Water stored in Lake Oroville is released through the 819 MW Edward Hyatt pumped-storage powerplant[27] 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.[28] The entire system generates approximately 2.2 billion kilowatt hours per year,[29] making up about a third of the total power generated by SWP facilities.[2]

Delta facilities[edit]

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 120,000 acre-feet (0.15 km3) per year is pumped into the 27.4-mile (44.1 km) North Bay Aqueduct, completed in 1988. The aqueduct delivers water to clients in Napa and Solano counties.[30]

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.[2] Here, the Harvey O. Banks Pumping Plant lifts water 224 feet (68 m) into the California Aqueduct. Completed in 1963, the eleven pump units can lift up to 10,670 cu ft/s (302 m3/s) of water – upgraded in 1986 from its original capacity of 6,400 cu ft/s (180 m3/s) across seven units.[31]

From here the water flows briefly south along the California Aqueduct to the 4,800 acre⋅ft (0.0059 km3) 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 188,000 acre⋅ft (0.232 km3) per year. Up to 77,100 acre⋅ft (0.0951 km3) of this water can be stored in Lake Del Valle, an offstream reservoir located near Livermore.[32]

California Aqueduct[edit]

San Luis Reservoir in July 2021

South of the Bay Area diversions, the bulk of the SWP water – ranging from 1 to 3.7 million acre-feet (1.2 to 4.6 km3) per year[20] – travels south along the western flank of the San Joaquin Valley through the California Aqueduct. The main section of the aqueduct stretches for 304 miles (489 km);[33] it is composed mainly of concrete-lined canals but also includes 20.7 miles (33.3 km) of tunnels, 130.4 miles (209.9 km) of pipelines and 27 miles (43 km) of siphons. The aqueduct reaches a maximum width of 300 feet (91 m) and a maximum depth of 30 feet (9.1 m); some parts of the channel are capable of delivering more than 13,000 cu ft/s (370 m3/s).[34] The section of the aqueduct that runs through the San Joaquin Valley includes multiple turnouts where water is released to irrigate roughly 750,000 acres (300,000 ha) of land on the west side of the valley.[35]

Dos Amigos Pumping Plant on the California Aqueduct
Aqueduct and surrounding farms in Kern County

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 2.04 million acre-feet (2.52 km3) of storage available in San Luis Reservoir.[36]

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 118 feet (36 m). 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 1,926 feet (587 m) 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 4,480 cu ft/s (127 m3/s) across fourteen units. Initial construction of Edmonston was completed in 1974, with the last three units installed in the 1980s.[37]

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.[23]

Coastal Branch[edit]

The Coastal Branch diverts about 48,000 acre⋅ft (0.059 km3) per year from the California Aqueduct to parts of San Luis Obispo and Santa Barbara counties. The aqueduct stretches for 143 miles (230 km), and is mostly made up of buried pipeline.[38] Pumping plants at Las Perillas, Badger Hill, Devil's Den, Bluestone, and Polonio Pass serve to lift the water over the California Coast Ranges. Once over the crest of the mountains, the water is reregulated in a series of small reservoirs numbered Tanks 1 through 5.[39] The Coastal Branch was completed in 1994 following a severe drought that led to calls for importation of SWP water.[40]

Through a pipeline known as the Central Coast Water Authority extension, completed in 1997,[40] the Coastal Branch supplies water to Lake Cachuma, a 205,000 acre⋅ft (0.253 km3) reservoir on the Santa Ynez River.[41]

West Branch[edit]

The terminus of the Angeles Tunnel at the Castaic Power Plant

From the terminus of the main California Aqueduct at Tehachapi Afterbay, the West Branch carries water to a second reservoir, Quail Lake, via the Oso Pumping Plant. The water then runs south by gravity to the 78 MW William E. Warne Powerplant, located on the 180,000 acre⋅ft (0.22 km3) Pyramid Lake reservoir.[42] The West Branch delivered about 537,000 acre⋅ft (0.662 km3) per year for the period 1995–2010.[43]

From Pyramid Lake, water is released through the Angeles Tunnel to the Castaic Power Plant on Elderberry Forebay and the 325,000 acre⋅ft (0.401 km3) Castaic Lake reservoir located north of Santa Clarita. Castaic Power Plant is a pumped-storage hydroelectric plant capable of producing 1,247 MW on peak demand. Together, Pyramid and Castaic Lakes form the primary storage for West Branch water delivered to Southern California. Water is supplied to municipalities in Los Angeles and Ventura counties.[citation needed]

East Branch[edit]

The East Branch takes water from Tehachapi Afterbay along the north side of the San Gabriel Mountains and San Bernardino Mountains to the Silverwood Lake reservoir, which can hold 73,000 acre⋅ft (0.090 km3). From here it passes through a tunnel under the San Bernardino Mountains to the Devil Canyon Powerplant, the largest "recovery plant", or aqueduct power plant, of the SWP system. The water then flows 28 miles (45 km) through the Santa Ana Tunnel to Lake Perris, which can store up to 131,400 acre⋅ft (0.1621 km3).

Water deliveries through the East Branch averaged 995,000 acre⋅ft (1.227 km3) per year from 1995 through 2012.[44] The East Branch principally provides water for cities and farms in the Inland Empire, Orange County, and other areas south of Los Angeles. Through Lake Perris, the Metropolitan Water District of Southern California receives a large portion of its water from the SWP.[45] Water is also supplied to the San Diego Aqueduct through a connection from Perris to Lake Skinner, further south.[46]

Proposed and unbuilt features[edit]

North Coast diversions[edit]

The original 1957 California Water Plan included provisions for dams on the Klamath, Eel, Mad and Smith Rivers of California's North Coast. Fed by prolific rainfall in the western Coast Ranges and Klamath Mountains, these rivers discharge more than 26 million acre-feet (32 km3) to the Pacific each year, more than that of the entire Sacramento River system.[47] The plan was basically a variation of a contemporary Bureau of Reclamation project, the Klamath Diversion.

The Eel River was one of the rivers targeted for diversion by the SWP after damaging floods in 1964.

A series of dams in these watersheds would shunt water through interbasin transfers into the Klamath River system. The centerpiece of the project would be a 15-million-acre-foot (19 km3) reservoir on the Klamath River – the largest man-made lake in California – from where the water would flow through the 60-mile (97 km) Trinity Tunnel into the Sacramento River, and thence to the canals and pump systems of the SWP. This would have provided between 5 and 10 million acre-feet (6.2 and 12.3 km3) of water each year for the SWP.[48] The diversion of the North Coast rivers, however were dropped from the initial SWP program.

In the mid-1960s, devastating flooding brought renewed interest in damming the North Coast rivers. The Department of Water Resources formed the State-Federal Interagency Task Force with the Bureau of Reclamation and the Army Corps of Engineers to develop plans for developing the rivers in the name of flood control – which would, incidentally, provide a way to divert some of their water into the SWP system.[49] Although most of the proposed projects met their demise over political squabbles, one that persisted was the Dos Rios Project on the Eel River system, which would have involved constructing a gigantic dam on the Middle Fork of the Eel River, diverting water through the Grindstone Tunnel into the Sacramento Valley.[50][51] Supporters of this project cited the disastrous Christmas flood of 1964 and the flood control benefits Dos Rios would provide to the Eel River basin.[52]

The Klamath and Dos Rios diversions were heavily opposed by local towns and Native American tribes, whose land would have been flooded under the reservoirs. Fishermen expressed concerns over the impact of the dams on the salmon runs of North Coast rivers, especially the Klamath – the largest Pacific coast salmon river south of the Columbia River. The project would have eliminated 98 percent of the salmon spawning grounds on the Klamath.[53] California Governor Ronald Reagan refused to approve the Dos Rios project, citing economic insensibility and fraudulent claims made by project proponents. The flood control benefits, for example, were largely exaggerated; the Dos Rios dam would have reduced the record 72-foot (22 m) Eel River flood crest of 1964 by only 8 inches (20 cm) had it been in place.[54]

In 1980, the North Coast rivers were incorporated into the National Wild and Scenic Rivers system, effectively eliminating the possibility of any projects to divert them.[55]

Peripheral Canal/California WaterFix[edit]

California WaterFix, is a planned twin forty-foot (12 m) tunnel project that would extend through the center of the Delta, 150 feet (46 m) below ground. Earlier designs called for a Peripheral Canal to skirt the Delta to the east. The tunnels would draw water from the Sacramento River to bypass the Sacramento–San Joaquin River Delta, a vast estuary and agricultural region consisting of over 700 miles (1,100 km) of tidal waterways. Supporters of the canal and tunnel have included the Central Valley farmers and the Metropolitan Water District and urban developers in Los Angeles. They claim it would eliminate the need to pull water directly through this sensitive region, reducing salinity intrusion and water quality problems during the dry season. The canal was included in the initial SWP planning, and the lack of the canal is among the principal reasons the SWP has never been able to deliver its full entitlement.[56]

Tunnel opponents believe the construction project would do extensive damage to the sensitive Delta ecosystem, farms and communities. Opponents also believe there will be long-term damage to the Delta ecosystem from fresh water being removed prior to flushing through the Delta and flowing more naturally to the San Francisco Bay.[57]

Governor Jerry Brown had supported a ballot initiative approving the canal in the early 1980s, and stated his intention to finish the project in its tunnel form during his second governorship (2011-2019). His successor, Gavin Newsom, has also supported the project. Supporters of the tunnel argue that water being drawn from the southern intakes creates problems for wildlife and changes the natural flow in these areas, which would be corrected by drawing water from farther north. Supporters also claim that the California levees are also vulnerable to earthquakes and directing water away from them protects the supply of water. Delta farmers, communities, and commercial salmon and bass fishermen are especially concerned about the tunnel. However, some Delta scientists disagree.[58] The new proposed canal would transport 1 million acre-feet (1.2 km3) of water to Silicon Valley, southern California and the majority of it would be directed to the Central Valley, a location with political influence and interest in the canal being built.[59]

Sites Reservoir[edit]

Since the 1980s, there has been interest in creating a large off-stream reservoir in the Sacramento Valley. Water "skimmed" off high winter flows in the Sacramento River would be pumped into a storage basin in the western side of the valley known as Sites Reservoir.[60] The reservoir would hold about 1.8 million acre-feet (2.2 km3) of water to be released into the Sacramento River during low-flow periods, boosting the water supply available for SWP entitlement holders and improving water quality in the Sacramento–San Joaquin Delta. This project has previously arisen in several forms, including proposals for a Glenn Reservoir or the Glenn-Colusa Complex on nearby streams, which would also have been receiving reservoirs for water sent east through the Dos Rios Project's Grindstone Tunnel or other transfers from North Coast rivers.[61]

With its large storage capacity, Sites Reservoir would increase the production and flexibility of California's water management system, yielding 470,000 to 640,000 acre⋅ft (0.58 to 0.79 km3) of new water per year.[62] This project is being seriously considered by the Department of Water Resources, as California's water system is expected to face serious shortfalls of 2 million acre-feet (2.5 km3) per year by 2020.[63] However, the project has been criticized for its high cost, and potential disruption of fish migration when large amounts of water are drawn from the Sacramento River during the wet season.

Los Banos Grandes[edit]

The Los Banos Grandes reservoir was first proposed in 1983[64] and would have served a similar purpose to Sites. The 1.73 million acre-feet (2.13 km3) reservoir would have been located along the California Aqueduct several miles south of San Luis Reservoir, and would have allowed for the storage of water during wet years when extra water could be pumped from the Sacramento–San Joaquin Delta.[65] Pumped-storage hydroelectric plants would have been built between Los Banos Grandes and the existing Los Banos flood control reservoir, and between that reservoir and the aqueduct.[66] The current status of Los Banos Grandes remains uncertain, as the DWR has been unable to appropriate funding since the 1990s.

Modern issues[edit]

2000–2016 Percent Area in U.S. Drought Monitor Categories

The existing SWP facilities are collectively known as Stage I. Stage II, which includes such works as the Peripheral Canal and Sites Reservoir, was to have been built beginning in the late 1970s and 1980s – but due to concerted opposition from Northern Californians, environmentalist groups and some economic interests, as well as the state's increasing debt, attempts to begin construction have all met with failure. Parties currently receiving SWP water are also opposed to its expansion, because water rates could be raised up to 300 percent to help pay for the cost. As a result, SWP capacity falls short by an average of 2 million acre-feet (2.5 km3) each year; contractors only occasionally receive their full shares of water.[67]

The disparity of costs to the project's various constituents has been a frequent source of controversy. Although the overall average cost of SWP water is $147 per acre-foot ($119 per 1,000 m3), agricultural users pay far less than their urban counterparts for SWP water. The Kern County Water Agency (the second largest SWP entitlement holder) pays around $45–50 per acre-foot ($36–41 per 1,000 m3) of SWP water, which is mostly used for irrigation. The Metropolitan Water District of Southern California (the largest entitlement holder) pays $298 per acre-foot ($241 per 1,000 m3). This basically means that cities are subsidizing the cost of farm water, even though the cities also provided primary funding for the construction of the SWP.[68]

In the early 1970s, the SWP system still had a lot of "surplus" – water supply developed through the construction of Oroville Dam, which was running unused to the Pacific Ocean because the water delivery infrastructure for Southern California had not yet been completed (and when it was, southern California was slow to use the water). The surplus water was given for irrigation in the San Joaquin Valley instead. Because the water would only be a temporary supply, farmers were advised to use it for seasonal crops (such as alfalfa or hay) rather than permanent crops such as orchards. Nevertheless, many farmers used the water to develop new permanent crops, creating a dependency on SWP water that is technically part of Southern California's entitlement,[69] This is now causing tensions as Southern California continues to increase its use of SWP water, decreasing the amount of surplus available to the system, especially in years of drought.

In dry years, water pumped from the Delta creates a hazard to spring-run salmon. As the Banks Pumping Plant pulls water from the Sacramento River southward across the Delta, it disrupts the normal flow direction of east to west that salmon smolt follow to the Pacific Ocean. Populations of salmon and steelhead trout have reached critically low levels in the decades after SWP water withdrawals began. The fish migration issue has become hotly contested in recent years, with rising support for the construction of the Peripheral Canal, which would divert water around the Delta, restoring the natural flow direction.

Water use and environmental problems associated with the SWP led to the creation of the CALFED Bay-Delta Program (CALFED) in 1994. The primary goals are to improve quality of SWP water while preventing further ecological damage in the Sacramento–San Joaquin Delta.[70]

In January 2014, after the moderately dry year of 2012 and the record California drought of 2013, the Department of Water Resources announced that the SWP would be making zero deliveries that year, the first time in the project's history, due to dangerously low snowpack and reservoir levels.[71] On April 18, 2014, the Department of Water Resources increased the SWP allocation back to five percent and that level remained until the initial allocation for 2015 was give on December 1, 2014.

Project data[edit]

Contracting water agencies[edit]

List of State Water Project water contractors[72]
Agency or entity Annual allocation Share
acre.ft dam3
Alameda County Flood Control and Water Conservation District 80,619 99,442 1.9%
Alameda County Water District 42,000 52,000 1.0%
Antelope Valley-East Kern Water Agency 144,844 178,662 3.5%
Butte County 27,500 33,900 0.6%
Castaic Water Agency 95,200 117,400 2.3%
Coachella Valley Water District 138,350 170,650 3.3%
Crestline-Lake Arrowhead Water Agency 5,800 7,200 0.1%
Desert Water Agency 55,750 68,770 1.3%
Dudley Ridge Water District 45,350 55,940 1.1%
Empire West Side Irrigation District 3,000 3,700 <0.1%
Kern County Water Agency 982,730 1,212,180 23.5%
Kings County 9,305 11,478 0.2%
Littlerock Creek Irrigation District 2,300 2,800 <0.1%
Metropolitan Water District of Southern California 1,911,500 2,357,800 45.8%
Mojave Water Agency 85,800 105,800 2.1%
Napa County Flood Control and Water Conservation District 29,025 35,802 0.7%
Oak Flat Water District 5,700 7,000 <0.1%
Palmdale Water District 21,300 26,300 0.5%
Plumas County Flood Control & Water Conservation District 2,600 3,200 <0.1%
San Bernardino Valley Municipal Water District 102,600 126,600 2.5%
San Gabriel Valley Municipal Water District 28,800 35,500 0.7%
San Gorgonio Pass Water Agency 17,300 21,300 4.2%
San Luis Obispo County Flood Control and Water Conservation District 25,000 31,000 0.6%
Santa Barbara County Flood Control and Water Conservation District 45,486 56,106 1.1%
Santa Clara Valley Water District 100,000 120,000 2.4%
Solano County Water Agency 47,756 58,906 1.1%
Tulare Lake Basin Water Storage District 87,471 107,894 2.1%
Ventura County Watershed Protection District 20,000 25,000 0.5%
Yuba City 9,600 11,800 0.2%
Total 4,172,686 5,146,932

Dams and reservoirs[edit]

†Background color denotes facility shared with Central Valley Project.

Dam Reservoir Year Capacity Stream Purpose
acre.ft dam3
Antelope Dam Antelope Lake 1964 47,466 58,548 Indian Creek Storage
B.F. Sisk Dam San Luis Reservoir* 1967 1,020,500 1,258,800 San Luis Creek/
California Aqueduct
Bethany Dam Bethany Reservoir 1967 5,250 6,480 California Aqueduct Reregulation
Castaic Dam Castaic Lake 1973 325,000 401,000 Castaic Creek/
West Branch California Aqueduct
Cedar Springs Dam Silverwood Lake 1971 73,000 90,000 West Fork Mojave River/
East Branch California Aqueduct
Del Valle Dam Lake Del Valle/
South Bay Aqueduct
1968 77,000 95,000 Arroyo Valle Storage
Elderberry Forebay Dam Elderberry Forebay 1974[73] 24,800 30,600 Castaic Creek/
West Branch California Aqueduct
Fish Barrier Dam 1964 Feather River Mitigation
Frenchman Dam Frenchman Lake 1961 55,477 68,430 Little Last Chance Creek Storage
Grizzly Valley Dam Lake Davis 1966 83,000 102,000 Big Grizzly Creek Storage
Little Panoche Detention Dam † Little Panoche Reservoir 1966 5,580 6,880 Little Panoche Creek Flood control
Los Banos Detention Dam † Los Banos Reservoir 1965 34,600 42,700 Los Banos Creek Flood control
O'Neill Dam O'Neill Forebay 1967 56,400 69,600 San Luis Creek/
California Aqueduct
Oroville Dam Lake Oroville 1968 3,537,577 4,363,537 Feather River Storage
Flood control
Perris Dam Lake Perris 1973 131,400 162,100 East Branch California Aqueduct Storage
Pyramid Dam Pyramid Lake 1970 180,000 220,000 Piru Creek/
West Branch California Aqueduct
Quail Lake Dam Quail Lake 7,580 9,350 West Branch California Aqueduct Reregulation
Tehachapi Afterbay Dam Tehachapi Afterbay California Aqueduct Reregulation
Thermalito Afterbay Dam Thermalito Afterbay 1968 57,040 70,360 Offstream Power
Thermalito Diversion Dam Diversion Pool 1968 13,350 16,470 Feather River Power
Thermalito Forebay Dam Thermalito Forebay 1968 11,770 14,520 Offstream Power
Total 5,746,790 7,088,560

*This is the portion of total capacity of San Luis Reservoir allocated to SWP; the total capacity is 2,041,000 acre⋅ft (2,518,000 dam3)


Aqueduct Length Annual deliveries Areas served
mi km acre.ft dam3
California Aqueduct 304 489 2,300,000 2,800,000 San Joaquin Valley
All SWP aqueducts
except for North Bay
Coastal Branch California Aqueduct 143 230 48,000 59,000 San Luis Obispo County
Santa Barbara County
East Branch California Aqueduct 140 230 995,000 1,227,000 Riverside County
San Bernardino County
Orange County
North Bay Aqueduct 27.4 44.1 120,000 150,000 Napa County
Solano County
South Bay Aqueduct 188,000 232,000 Alameda County
Santa Clara County
West Branch California Aqueduct 24.7 39.8 537,000 662,000 Ventura County
Los Angeles County

Pump plants[edit]

Pumping plants[74]
Name Aqueduct Lift
ft m
Banks California Aqueduct 244 74
Dos Amigos California Aqueduct 118 36
Buena Vista California Aqueduct 205 62
Teerink California Aqueduct 233 71
Chrisman California Aqueduct 518 158
Edmonston California Aqueduct 1,926 587
Pearblossom East Branch California Aqueduct 540 160
Las Perillas Coastal Branch California Aqueduct 55 17
Badger Hill Coastal Branch California Aqueduct 151 46
Devil's Den Coastal Branch California Aqueduct 521 159
Bluestone Coastal Branch California Aqueduct 484 148
Polonio Pass Coastal Branch California Aqueduct 533 162
Barker Slough North Bay Aqueduct 120 37
Cordelia North Bay Aqueduct 138 42
South Bay South Bay Aqueduct 566 173
Del Valle South Bay Aqueduct 38 12
Oso West Branch California Aqueduct 231 70
Pearblossom East Branch California Aqueduct 540 160


Name Watercourse Capacity Annual generation
Alamo East Branch California Aqueduct 17 MW 79 GWh Recovery
Castaic West Branch California Aqueduct 1,247 MW 624 GWh Pumped-storage
Devil Canyon East Branch California Aqueduct 240 MW 993 GWh Recovery
Foothill Feeder West Branch California Aqueduct 11 MW 47 GWh Recovery
Gianelli (San Luis) Offstream 424 MW 200 GWh Pumped-storage
Hyatt (Oroville) Feather River 819 MW 1,386 GWh Pumped-storage
Mojave Siphon East Branch California Aqueduct 32.4 MW 63 GWh Recovery
Thermalito Offstream 120 MW 179 GWh Pumped-storage
Thermalito Diversion Feather River 3.3 MW 10 GWh Conventional
Warne West Branch California Aqueduct 78 MW 266 GWh Recovery
2,991.7 MW
  • Conventional: Power plant utilizing flow of river or stream through dam
  • Pumped-storage: See Pumped-storage hydroelectricity
  • Recovery: Power plant utilizing flow of aqueduct or canal

See also[edit]


  1. ^ "California State Water Project At A Glance" (PDF). California Department of Water Resources. Retrieved October 16, 2013.
  2. ^ a b c "California State Water Project Today". California Department of Water Resources. July 18, 2008. Archived from the original on September 1, 2010. Retrieved September 12, 2013.
  3. ^ Sabet, Hossein; Creel, Curtis L. (September 1991). "Model Aggregation for California State Water Project". Journal of Water Resources Planning and Management. 117 (5): 549–564. doi:10.1061/(ASCE)0733-9496(1991)117:5(549). ISSN 0733-9496.
  4. ^ Reynolds, Robin R.; Madsen, Welby R. (November 1967). "Automation in California's State Water Project". Journal of the Pipeline Division. 93 (3): 15–23. doi:10.1061/JPLEAZ.0000110. ISSN 0569-8014.
  5. ^ Meier, Fred. "The California State Water Project" (PDF). University of California, Los Angeles. Archived from the original (PDF) on October 17, 2013. Retrieved October 17, 2013.
  6. ^ Quinton, Amy (October 7, 2013). "California's Water Supply, A 700 Mile Journey". Capital Public Radio. Retrieved October 15, 2013.
  7. ^ "History of the State Water Project". State Water Contractors. Archived from the original on October 16, 2013. Retrieved October 18, 2013.
  8. ^ "The Big Water Projects in California". California Water Impact Network. Archived from the original on October 1, 2013. Retrieved October 15, 2013.
  9. ^ Agee, p. 174
  10. ^ "History of Water Development and the State Water Project". California Department of Water Resources. October 28, 2008. Archived from the original on August 23, 2010. Retrieved October 19, 2013.
  11. ^ Reisner, p. 269
  12. ^ "A Look Back at Past California Water Plans" (PDF). California Water Plan Update 2005. California Department of Water Resources. Retrieved October 15, 2013.
  13. ^ Bourne, Joel (April 2010). "California's Pipe Dream: A heroic system of dams, pumps, and canals can't stave off a water crisis". National Geographic. Archived from the original on April 15, 2010.
  14. ^ Water Education Foundation (2005). "A California Water Chronology" (PDF). California Water Plan. California Department of Water Resources. Retrieved October 15, 2013.
  15. ^ a b "California State Water Project Milestones". California Department of Water Resources. April 29, 2008. Archived from the original on December 19, 2017. Retrieved October 18, 2013.
  16. ^ Arax, Mark; Rick Wartzman (2005). The King of California: J. G. Boswell and the Making of a Secret American Empire. New York City: PublicAffairs. ISBN 1-58648-281-5.
  17. ^ Piper, Karen (2014). The Price of Thirst: Global Water Inequality and the Coming Chaos. University of Minnesota Press. ISBN 9780816695423.
  18. ^ Gottlieb, Robert (1988). A Life of Its Own: The Politics and Power of Water. San Diego, Calif.: Harcourt Brace Jovanovich. pp. 12–13. ISBN 9780151951901.
  19. ^ "Chronology of the State Water Project, Its Monterey Contract Amendments and the Kern Water Bank (1929–2010)" (PDF). Center for Biological Diversity. Retrieved October 16, 2013.
  20. ^ a b "California State Water Project Water Contractors". California Department of Water Resources. May 6, 2013. Archived from the original on February 8, 2018. Retrieved October 16, 2013.
  21. ^ Meeks, Alexandra; Andone, Dakin (August 6, 2021). "California hydropower plant forced to shut down as water levels fall at Lake Oroville". CNN. Retrieved May 22, 2022.
  22. ^ "California State Water Project's Upper Feather River Lakes" (PDF). California Department of Water Resources. Archived from the original (PDF) on October 3, 2013. Retrieved September 12, 2013.
  23. ^ a b "California State Water Project" (PDF). California Department of Water Resources (Map of Facilities). Archived from the original (PDF) on October 2, 2013. Retrieved October 15, 2013.
  24. ^ a b "Lake & Dam". State Water Project – Oroville Facilities. California Department of Water Resources. June 17, 2009. Retrieved September 12, 2013.
  25. ^ "Oroville Facilities Federal Energy Regulatory Commission (FERC) Relicensing Project No. 2100". Information Center for the Environment. University of California, Davis. Archived from the original on August 31, 2013. Retrieved September 12, 2013.
  26. ^ Arrigoni, Barbara (August 17, 2012). "DWR speaker highlights construction of Oroville Dam". Oroville Mercury–Register. Archived from the original on October 14, 2013. Retrieved September 12, 2013.
  27. ^ "Edward Hyatt Powerplant". State Water Project – Oroville Facilities. California Department of Water Resources. June 17, 2009. Archived from the original on April 7, 2012. Retrieved September 12, 2013.
  28. ^ "Thermalito Facilities". State Water Project – Oroville Facilities. California Department of Water Resources. June 17, 2009. Archived from the original on February 22, 2017. Retrieved September 12, 2013.
  29. ^ "Oroville Facilities". Hydropower License Planning and Compliance Office. California Department of Water Resources. October 11, 2013. Archived from the original on January 28, 2015. Retrieved October 18, 2013.
  30. ^ "California's State Water Project" (PDF). Parker Groundwater. Archived from the original (PDF) on March 4, 2016. Retrieved September 12, 2013.
  31. ^ "Chapter 16: Power" (PDF). 2003 Environmental Water Account. U.S. Bureau of Reclamation. Archived from the original (PDF) on October 16, 2013. Retrieved September 12, 2013.
  32. ^ "South Bay Aqueduct (Bethany Reservoir and Lake Del Valle)" (PDF). California Department of Water Resources. Archived from the original (PDF) on October 3, 2013. Retrieved September 12, 2013.
  33. ^ USGS Topo Maps for United States (Map). Cartography by United States Geological Survey. ACME Mapper. Retrieved October 14, 2013.
  34. ^ "California Aqueduct – State Water Project" (PDF). University of California, Davis. Retrieved October 14, 2013.[permanent dead link]
  35. ^ "California State Water Project Overview". California Department of Water Resources. August 11, 2010. Retrieved September 12, 2013.
  36. ^ San Luis Unit Project. Central Valley Project (Report). U.S. Bureau of Reclamation. April 21, 2011. Archived from the original on November 12, 2011.
  37. ^ "Engineering : A. D. Edmonston Pumping Plant Pump Replacement". California Department of Water Resources. February 28, 2011. Retrieved October 30, 2013.
  38. ^ "Ceremony Marks Arrival of State Water to the Central Coast" (PDF). California Department of Water Resources and Central Coast Water Authority Joint News Release. California Department of Water Resources. July 18, 1997. Archived from the original (PDF) on October 2, 2013. Retrieved October 14, 2013.
  39. ^ "State Water Project: Coastal Branch Aqueduct" (PDF). California Department of Water Resources. August 2012. Archived from the original (PDF) on October 3, 2013. Retrieved October 14, 2013.
  40. ^ a b "History of Water and Wastewater Management" (PDF). County of Santa Barbara. Archived from the original (PDF) on May 19, 2012. Retrieved October 14, 2013.
  41. ^ "Cachuma Project". U.S. Bureau of Reclamation. April 18, 2011. Archived from the original on October 16, 2013. Retrieved October 30, 2013.
  42. ^ "William E. Warne Power Plant Brochure" (PDF). California Department of Water Resources. November 2010. Archived from the original (PDF) on October 3, 2013. Retrieved October 14, 2013.
  43. ^ "USGS Gage #11109398 on the West Branch California Aqueduct at William Warne Power Plant near Gorman, CA". National Water Information System. U.S. Geological Survey. 1995–2010. Retrieved October 20, 2013.
  44. ^ "USGS Gage #10260776 on the East Branch California Aqueduct at Alamo Power Plant near Gorman, CA". National Water Information System. U.S. Geological Survey. 1995–2010. Retrieved October 20, 2013.
  45. ^ "State Water Project". Padre Dam Municipal Water District. Retrieved October 20, 2013.
  46. ^ "San Diego Project". U.S. Bureau of Reclamation. May 17, 2011. Archived from the original on October 17, 2013. Retrieved October 20, 2013.
  47. ^ Kelly, Walt. "California Water Today" (PDF). Public Policy Institute of California.
  48. ^ Reisner, pp. 267–270
  49. ^ Reisner, p. 358
  50. ^ Kirsch, Jonathan (August 31, 1994). "Book Review / Nonfiction : One Man's Battle Against California's Politics of Water : The River Stops Here: How One Man's Battle to Save His Valley Changed the Fate of California by Ted Simon". Los Angeles Times. Retrieved November 13, 2013.
  51. ^ Dunning, Harrison C. (Spring 2002). "California Water: Will There Be Enough?" (PDF). Environs. University of California, Davis. 25 (2): 59–65. Archived from the original (PDF) on December 25, 2013. Retrieved November 13, 2013.
  52. ^ Reisner, pp. 199–200
  53. ^ Reisner, p. 268
  54. ^ Reisner, p. 359
  55. ^ "Protection for Wild Rivers". Los Angeles Times. January 24, 1985. Retrieved November 13, 2013.
  56. ^ Reisner, pp. 351–362
  57. ^ "Destroying the Delta". April 24, 2013. Retrieved July 19, 2019.
  58. ^ Pyke, Robert (November 23, 2013). "Letter" (PDF).
  59. ^ Newton, Jim (June 25, 2012). "Newton: Water ethics and a peripheral canal" (Opinion). Los Angeles Times. Retrieved November 13, 2013.
  60. ^ Brown, Jerry; Bettner, Thaddeus (April 13, 2013). "Storing water is an old concept that takes on new importance". Contra Costa Times. Walnut Creek, California. Retrieved December 24, 2013.
  61. ^ Reisner, p. 361
  62. ^ "Sites Reservoir: Frequently Asked Questions" (PDF). California Department of Water Resources. 2007–2009. pp. 4–5. Archived from the original (PDF) on January 1, 2014. Retrieved December 24, 2013.
  63. ^ Meeker, Susan (August 12, 2011). "Sites Reservoir considered again". Colusa County Sun Herald. Colusa, California. Archived from the original on October 16, 2013. Retrieved December 24, 2013.
  64. ^ Richard E. Howitt; et al. (1999). Integrated economic-engineering analysis of California's future water supply (PDF). Report for the State of California Resources Agency, Sacramento, California. p. 26. Archived from the original (PDF) on October 25, 2014. Retrieved October 25, 2014.
  65. ^ Donna Beth Weilenman (April 2, 2013). "The Delta: Garamendi plan offered as alternative to 'destructive plumbing plan' of tunnels". Benicia Herald. Archived from the original on December 24, 2014.
  66. ^ "Los Banos Grandes Facilities Sycamore Pilot Project Report Number III" (PDF). Department of Resources Division of Planning, State of California. July 22, 1994. Archived from the original (PDF) on October 16, 2013. Retrieved October 16, 2013.
  67. ^ Richard Howitt and Dave Sunding. "Water Infrastructure and Water Allocation in California". In J. Siebert (ed.). California Agriculture: Dimensions and Issues (PDF). University of California Giannini Foundation. pp. 181–190. Archived from the original (PDF) on October 17, 2013. Retrieved October 17, 2013.
  68. ^ "Mismanaging the California State Water Project" (PDF). Public Citizen, California.
  69. ^ Reisner, pp. 366–370
  70. ^ "CALFED Bay Delta Programme" (PDF). CH2M HILL. Archived from the original (PDF) on October 24, 2013. Retrieved October 17, 2013.
  71. ^ Boxall, Bettina (January 31, 2014). "California drought prompts first-ever 'zero water allocation'". Los Angeles Times. Retrieved February 3, 2014.
  72. ^ "2015 State Water Project Allocation" (PDF). California Department of Water Resources. Retrieved February 10, 2017.
  73. ^ "Dams Within the Jurisdiction of the State of California (A–G)" (PDF). California Department of Water Resources, Division of Safety of Dams. Archived from the original (PDF) on March 9, 2012. Retrieved November 1, 2013.
  74. ^ "Management of the California State Water Project" (PDF). Metropolitan Water District of Southern California. August 2014. Retrieved February 26, 2017.
  75. ^ "California Hydroelectric Statistics & Data". California Energy Commission. Archived from the original on January 28, 2015. Retrieved January 24, 2015.

Works cited[edit]

Further reading[edit]

  • Water Education Foundation (2008). Layperson's Guide to the State Water Project. Water Education Foundation.

External links[edit]