Castaic Dam is an embankment dam in northern Los Angeles County, California, near the city of Castaic. Although located on Castaic Creek, a major tributary of the Santa Clara River, Castaic Creek provides little of its water. The lake is the terminus of the West Branch of the California Aqueduct, part of the State Water Project. The dam was built by the California Department of Water Resources and construction was completed in 1973. The lake has a capacity of and stores drinking water for the western portion of the Greater Los Angeles Area.