The dam is constructed of earthfill and is 190 feet (58 m) tall, measured from the elevation of the original streambed.

The dam was built by the city of Los Angeles and was completed in 1934 (91 years ago) (1934) Official opening ceremonies were held at noon on March 28, 1934.

The reservoir is part of the Los Angeles Aqueduct system, which is where it gets much of its water.

The reservoir's drainage basin is only 13.6 square miles (35 km2) where the average annual rainfall is 14–20 inches (360–510 mm).

Its purpose is to provide regulation of releases and to store water in case there is an interruption upstream.