Big Tujunga Dam is a 244ft-high concrete arch dam in Los Angeles County, California, spanning Big Tujunga Canyon northeast of Sunland, in the foothills of the San Gabriel Mountains. Completed in 1931, it provides flood control and groundwater recharge for the San Fernando Valley.Its reservoir is called Big Tujunga Reservoir, and collects runoff from a watershed of 82mi2. Although it is located inside the Angeles National Forest, public access to the lake is forbidden. The water is usually kept at a low level, in order to protect against winter floods.DescriptionThe dam is 208ft high from the riverbed, 244ft high from the foundations, and 830ft long. It has a width of 138ft at the base, tapering to 8ft at the crest. The storage capacity is 5960acre feet at the spillway, with a minimum pool of 1210acre feet to prevent sediment and debris from entering the dam's outlets.After the completion of Hansen Dam downstream, the importance of Big Tujunga Dam for flood control has decreased; however, it is still directly responsible for protecting about 4,600 residents living in the floodplain of Big Tujunga Canyon. In addition, the dam conserves about 4500acre feet of runoff per year for drinking water and groundwater recharge purposes. This saves the city of Los Angeles about $2,250,000 annually due to the cost difference between local and imported water.
