Elderberry Forebay Dam

Elderberry Forebay Dam is a dam located in the Sierra Pelona Mountains of northwestern Los Angeles County, California.
The dam partitions Elderberry Forebay from Castaic Lake. 
It forms the headwater reservoir for Castaic Power Plant, a pumped-storage hydroelectricity generation facility.
The dam was completed in 1974 as part of the California State Water Project.