The West Branch Aqueduct supplies water for Los Angeles and other Southern California cities.

The West Branch is one of two State Water Project aqueducts serving Southern California.

After being pumped over the Tehachapi Mountains from the Edmonston Pumping Plant, water for the West Branch Aqueduct is then stored in Pyramid Lake and Castaic Lake [See also East Branch Aqueduct, which serves the Inland Empire near Riverside.]