Clifton Court Forebay

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Clifton Court Forebay
Location of Clifton Court Forebay in California, USA.
Location of Clifton Court Forebay in California, USA.
Clifton Court Forebay
Location of Clifton Court Forebay in California, USA.
Location of Clifton Court Forebay in California, USA.
Clifton Court Forebay
LocationSan Joaquin River Delta
Contra Costa County, California
Coordinates37°49′48″N 121°33′24″W / 37.8299°N 121.5568°W / 37.8299; -121.5568[1]Coordinates: 37°49′48″N 121°33′24″W / 37.8299°N 121.5568°W / 37.8299; -121.5568[1]
Primary inflowsOld River
Primary outflowsCalifornia Aqueduct
Delta–Mendota Canal
Catchment area6 square miles (16 km2)[2]
Basin countriesUnited States
Max. length2.5 miles (4.0 km)
Max. width2 miles (3.2 km)
Surface area2,500 acres (1,000 ha)[2]
Average depth10 m (33 ft)
Max. depth20 m (66 ft)
Water volume29,000 acre⋅ft (36 hm3)[2]
Residence time4 months
Surface elevation3 feet (0.91 m)[1]

Clifton Court Forebay is a reservoir in the San Joaquin River Delta region of eastern Contra Costa County, California, 17 mi (27 km) southwest of Stockton. The estuary region the forebay is located in is only 1m to 3m above mean sea level.


The body of water was created in 1969 by inundating a 2,200-acre (890 ha) tract as part of the California State Water Project.[3]

It serves as the intake point of the California Aqueduct for transport to Southern California, and feeds the Delta–Mendota Canal (a part of the Central Valley Project) to recharge San Joaquin Valley river systems.[4]

Geological context[edit]

If a large enough earthquake happens near or at the Clifton Court Forebay, the California water system for irrigation and municipal use will be adversely affected. Several earthquakes have nearly shut down the Forebay. The 2014 South Napa earthquake and the 1989 Loma Prieta earthquake came very close to shutting down the Forebay intake system.

The Clifton Forebay is a wetland system that drained nearby small rivers into the Pacific Ocean. Only in recent times was its freshwater drainage functions turned into a gateway to water storage.

The Central Valley region that this forebay interfaces with is very gradually filling in the central valley with sediments. The region may be rebounding from recent run ins with glaciations that affected North America.

In popular culture[edit]

A documentary about the decline of the United States' infrastructure, The Crumbling of America,[5] was commissioned by the U.S. A&E network in the late 2000s. The documentary is typically shown on the History television channel in the United States, although other educational broadcasters globally have shown it. It features the Clifton Court Forebay as a "strategic piece of California freshwater infrastructure" subject to shutdown for up to two years if struck by an earthquake of magnitude 7.5 or greater.

See also[edit]

Related sites[edit]


  1. ^ a b "Clifton Court Forebay". Geographic Names Information System. United States Geological Survey.
  2. ^ a b c "Dams Within the Jurisdiction of the State of California (A-G)" (PDF). California Department of Water Resources, Division of Safety of Dams. Retrieved November 1, 2012.
  3. ^ Kevin W. Clark; Mark D. Bowen; Ryan B. Mayfield; Katherine P. Zehfuss; Justin D. Taplin; Charles H. Hanson (March 2009). "Quantification of Pre-Screen Loss of Juvenile Steelhead in Clifton Court Forebay" (.PDF). California Natural Resources Agency, Department of Water Resources, State of California: 1–3. Retrieved September 29, 2009. Cite journal requires |journal= (help)
  4. ^ The "The American Aqueduct and the Great California Water Saga", February 2014.
  5. ^ "The Crumbling of America (2:49 introductory clip)". Retrieved September 11, 2013.