Elderberry Forebay

Elderberry Forebay
Elderberry Forebay
Location	Los Angeles County, California
Coordinates	34°34′19″N 118°38′16″W / 34.5719°N 118.6379°W / 34.5719; -118.6379[1]
Type	Reservoir
Primary inflows	West Branch California Aqueduct
Primary outflows	Castaic Creek
Catchment area	81.6 square miles (211 km2)[2]
Basin countries	United States
Surface area	450 acres (180 ha)[2]
Water volume	28,400 acre⋅ft (35.0×10^6 m3)[2]
Surface elevation	1,519 feet (463 m)[1]
References	[1][2]

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 Forebay Dam at its southern edge. Entering the northern end of the forebay is the west branch of the California Aqueduct, which connects the forebay to Pyramid Lake through the Angeles Tunnel.^[2][3]

A component of the California State Water Project, the reservoir was partitioned from Castaic Lake in 1974 to store water for pumped-storage hydroelectricity generation.^[2][3] During on-peak energy-demand hours, water flows 7.5 miles (12.1 km) from Pyramid Lake through the Angeles Tunnel and then on to the turbines of the Castaic Power Plant, producing electricity. From there, the water flows into Elderberry Forebay. During off-peak hours (including nighttime and Sundays), water is pumped from the forebay, back through the tunnel and into Pyramid Lake.^[3]