The Angeles Tunnel is a , water tunnel located in the

Sierra Pelona Mountains The Sierra Pelona, also known as the Sierra Pelona Ridge or the Sierra Pelona Mountains, is a mountain ridge in the Transverse Ranges in Southern California. Located in northwest Los Angeles County, the ridge is bordered on the north by the San An ...

Los Angeles County Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the most populous county in the United States and in the U.S. state of California, with 9,861,224 residents estimated as of 2022. It is the ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, about north of

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

."Angeles Tunnel", U.S. Geological Survey.''Pyramid Lake'' 2000, p. 1.American Society 1970, p. 131. It was constructed between 1967 and 1970 as part of the

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 serves as the final leg of the

west branch West Branch may refer to: Communities * West Branch, Iowa, city in Cedar and Johnson counties * West Branch, Michigan, city in Ogemaw County * West Branch, New Brunswick, in the Local Service District of Weldford Parish * West Branch River John, i ...

of the

California Aqueduct The Governor Edmund G. Brown California Aqueduct is a system of canals, tunnels, and pipelines that conveys water collected from the Sierra Nevada Mountains and valleys of Northern and Central California to Southern California. Named after Cali ...

, which carries

Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...

water to

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

residents.Roach 2008, p. 235. The tunnel also supplies water to the adjacent

Castaic Power Plant Castaic Power Plant, also known as the Castaic Pumped-Storage Plant, is a seven unit pumped-storage hydroelectric plant, operated by the Los Angeles Department of Water and Power, which provides peak load power from the falling water on the Wes ...

, a

pumped-storage hydroelectricity Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential ...

generation facility.''Castaic Lake'' 2007."South SWP Hydropower", Calif. Dept. of Water Resources. To facilitate power generation, the tunnel's flow is bidirectional. During on-peak energy-demand hours, water flows downhill through the tunnel, starting at an elevation of in Pyramid Lake, and then falling over to the turbines of the Castaic Power Plant at ."Castaic Powerplant", U.S. Geological Survey. The water is then stored in the

Elderberry Forebay Elderberry Forebay is a small reservoir in Los Angeles County, California, which serves as the pumping forebay of the Castaic Power Plant. It located at the upper end of the larger Castaic Lake and is separated from the lake by Elderberry Fore ...

, adjacent to

Castaic Lake Castaic Lake (Chumash: ''Kaštiq'') is a reservoir formed by Castaic Dam on Castaic Creek, in the Sierra Pelona Mountains of northwestern Los Angeles County, California, United States, near the town of Castaic. The California Office of Environ ...

. During off-peak hours, water is pumped uphill through the tunnel in the opposite direction from Elderberry Forebay and returned to Pyramid Lake. This operation reduces the energy cost of moving water along the California Aqueduct.

Notes

References

* * * * * * * * {{coord, 34.5859, -118.6662, type:landmark, display=title Water tunnels in the United States California State Water Project Water in California Tunnels in Los Angeles County, California

See also

Notes

References