Brea

Brea Dam, constructed, operated and maintained by the Corps of Engineers (COE), is a single purpose flood control project. The dam is located in the city of Fullerton just upstream of the fork of Brea Boulevard and Harbor Boulevard. Construction on the dam began in July 1940 and was completed in March 1942. Brea Dam, one of the units of the flood-control project for the San Gabriel River Basin and Orange County, California, was conceived under authorization of the Flood Control Act of 22 June 1936.

Brea Dam controls 22.0 square miles of drainage area of Brea Creek and its tributaries. Brea Creek generally flows southwesterly into the reservoir. Below the dam, the creek flows southward through the central business district of the city of Fullerton, where it turns westward to join Coyote Creek, a tributary of the San Gabriel river.

Brea Dam consists of : (1) an earthfilled embankment; (2) a reinforced concrete outlet works; (3) an ungated outlet; (4) a detached spillway; (5) saddle dike; and (6) reservoir.

The stand-by gate setting for the dam is currently 2 gates open at 3.5 feet. The regulation schedule at the dam during flood events is based on a combination of precipitation at the Brea Dam station during the preceding 30-minute period and current water surface elevation. Additionally, the downstream channel capacity must be monitored, and if need be, modify releases from the published schedule to prevent overtopping of the downstream channel.

The channel capacity immediately downstream of the dam is 2,000 cfs as provided by a rectangular reinforced concrete channel. For next three miles, the capacity increases to a 2,200 cfs to 3,000 cfs capacity rectangular reinforced concrete channel. In the next 2 miles of channel, the capacity expands to 11,000 cfs. For last mile, just upstream of the confluence with Coyote Creek, the capacity ranges from 3,500 cfs to 4,000 cfs.

The current water control manual for Brea Dam was approved in May 1990.