Delta
Aerial view of Del Valle Dam and Lake Del Valle.
The Delta Field Division operates and maintains State Water Project facilities within the Sacramento-San Joaquin Delta. Harvey O. Banks Pumping Plant, which lifts water into the beginning of the California Aqueduct, is part of this field division and located almost 20 miles southwest of the city of Stockton.
The North Bay and South Bay aqueducts lie within the field division’s jurisdiction. The North Bay’s underground pipeline and facilities provide water supply for Napa and Solano counties. While South Bay branches off from Bethany Reservoir to serve Santa Clara and Alameda counties.
Two major environmental protection projects include Skinner Fish Protective Facility, a fish salvage operation, and the Suisun Marsh Salinity Control Gates, a water quality control structure that protects one of the largest continuous brackish water marshes in the nation.
Patterson Dam & Reservoir
As the terminus for the Livermore Valley Canal, Patterson Reservoir provides off-line storage for Alameda County Flood Control and Water Conservation District’s Zone 7 Treatment Plant. From this reservoir, located near Livermore, the South Bay Aqueduct continues to deliver water to Lake Del Valle and to its terminus at the Santa Clara Terminal Reservoir in San Jose. The dam and reservoir were constructed between 1960 and 1962.
Bethany Dams and Reservoir
The South Bay Aqueduct begins at Bethany Reservoir, 1.5 miles downstream from Banks Pumping Plant. The reservoir, impounded by five earthen dams, serves as the forebay for South Bay Pumping Plant and the afterbay of Banks Pumping Plant. Bethany serves as a conveyance facility and also provides recreational opportunities.
Construction of the forebay dam began in 1959, and was completed in 1961, with the adjacent dams and connecting channel constructed between 1965 and 1967.
Clifton Court Forebay Dam & Forebay
Clifton Court Forebay, located in the southwestern edge of the Sacramento-San Joaquin Delta about 10 miles northwest of the city of Tracy, is a shallow reservoir at the head of the California Aqueduct. The forebay provides storage and regulation of flows into Banks Pumping Plant. Before completion of the forebay, Italian Slough connected directly to the present-day intake channel. Work started on the forebay in 1967 and was completed in 1969.
Located in the Delta at the eastern end of the Montezuma Slough near Collinsville, the Suisun Marsh Salinity Control Gates maintain proper salinity levels in the Suisun Marsh during periods of low Delta outflow. These levels affect the growth of food plants for waterfowl that use the marsh as a wintering area.
Operation of the gates is based on modifying the tidal flows through Montezuma Slough. The radial gates are opened to allow better quality water from the Sacramento and San Joaquin rivers to flow westerly into the marsh. As the direction of tidal flows reverses, the radial gates close to trap the better-quality water, which will dilute the saltier water flowing easterly into the marsh from Grizzly Bay.
Construction on the gates began in 1986, and test of tidal pumping began in 1988. They were declared operational in 1989.
The North Bay Aqueduct, located northeast of San Francisco, is an underground pipeline that extends for 27.6 miles from Barker Slough, in the Delta, and ends at two water storage tanks at the Jamieson Canyon Water Treatment Plant in the City of Napa.
The aqueduct was constructed in two phases. Phase I (1967 to 1968) began serving Napa County in 1968, using an interim supply of water from the U.S. Bureau of Reclamation’s Solano Project. Phase II (1985 to 1988) extended the pipeline 23 miles from the Cordelia Surge Tank eastward to Barker Slough.
Water is pumped from the Delta at Barker Slough Pumping Plant through a pipeline to Travis Surge Tank and then flows to the Cordelia Pumping Plant.
Barker Slough Pumping Plant
Located on the northwestern end of the Sacramento-San Joaquin Delta, Barker Slough Pumping Plant marks the beginning of the North Bay Aqueduct. Its pumps lift water from Barker Slough into a pipeline that conveys the water to the Travis Surge Tank, nearly nine miles away. Water then flows by gravity to Cordelia Pumping Plant. Construction began in 1986 and was completed in 1987.
Cordelia Pumping Plant and Forebay
Part of the North Bay Aqueduct, the Cordelia Pumping Plant is in Solano County near Highway 80. It has three separate discharge pipelines. Construction began in 1986 and was completed in 1988.
Cordelia Pumping Plant Forebay is a shallow reservoir that permits regulation of flows into Cordelia Pumping Plant. It was constructed between 1986 and 1987.
Napa Turnout Reservoir
The western terminus of the North Bay Aqueduct, the Napa Turnout Reservoir, is located in eastern Napa County near Highway 12. The steel tank receives water from a four-mile pipeline connecting it with the Cordelia Surge Tank.
Constructed between 1967 and 1968, the Napa Turnout Reservoir was originally filled by the SWP’s North Bay Interim Pumping Plant. The reservoir currently stores water for delivery to Napa County Flood Control and Water Conservation District.
The South Bay Aqueduct was the first delivery system completed in the State Water Project and has been conveying water to Alameda and Santa Clara counties since 1962 and 1965, respectively. The 42.9-mile system consists of 8.4 miles of canals, 32.9 miles of pipeline, and 1.6 miles of tunnels.
South Bay Pumping Plant
Known as the heart of the South Bay Aqueduct, the South Bay Pumping Plant is located at the upper end of Bethany Reservoir and lifts water into the first reach of the South Bay Aqueduct. It is situated in the northeastern corner of Alameda County, about 12 miles west of Tracy. The plant’s staged construction took place between 1960 and 1969. A 2008-2014 enlargement project added four pumping units, a new pipeline, and reservoir.
Dyer Reservoir
Dyer Reservoir supports the SWP during "on-peak" hours by receiving up to 525-acre-feet of water from the South Bay Pumping Plant at night when electricity rates are lower. The water flows by gravity from the reservoir into the Aqueduct to the Bay Area communities. This Reservoir is not open to the public for recreation.
Patterson Dam & Reservoir
As the terminus for the Livermore Valley Canal, Patterson Reservoir provides off-line storage for Alameda County Flood Control and Water Conservation District’s Zone 7 Treatment Plant. From this reservoir, located near Livermore, the South Bay Aqueduct continues to deliver water to Lake Del Valle and to its terminus at the Santa Clara Terminal Reservoir in San Jose. The dam and reservoir were constructed between 1960 and 1962.
Del Valle Dam & Lake Del Valle
Located in Arroyo Del Valle, about four miles from the city of Livermore in Alameda County, Del Valle Dam and Lake Del Valle provide regulatory storage for the South Bay Aqueduct, flood control (40,000 acre-feet maximum operating storage) for the Alameda Creek, conservation of storm runoff, recreation, and fish and wildlife enhancement. The facility was constructed from 1966 to 1968.
Del Valle Pumping Plant
Constructed between 1967 and 1969, the Del Valle Pumping Plant pumps water during low demand periods from the South Bay Aqueduct into Lake Del Valle for storage and conveys it back to the aqueduct when demand is high. When reservoir water level is too low to allow flow back into the aqueduct via gravity, it serves as a booster station in the branch line between South Bay Aqueduct and Lake Del Valle. The plant lies immediately downstream of Del Valle Dam, about 4.5 miles south of the city of Livermore, and is the smallest SWP pumping plant.
Santa Clara Terminal Reservoir
The Santa Clara Terminal Reservoir is a steel holding tank located five miles east of San Jose on the site of the Santa Clara Valley Water District’s Penitencia Treatment Facilities. It supplies domestic water to the Santa Clara area through a feed line to the treatment plant and an overflow pipe ending at the district’s groundwater percolation basin. It was constructed from 1964 to 1965.