The dam controls runoff from a rugged catchment area of 27 square miles (70 km2) in the San Gabriel Mountains.

[2] The dam was built by the Los Angeles District of the U.S. Army Corps of Engineers.

The reservoir behind the dam is usually dry, but can fill with up to 11,880 acre-feet (14,650,000 m3) of water after large flooding events.

[1] A concrete overflow spillway on the west side prevents overtopping and drains to the San Antonio and Chino Creek channels, which were lined with concrete between 1956 and 1960 to protect against such an event.

[2] A project has been underway since 2012 to remediate seepage problems at the toe of the dam during heavy rainstorms.