LOS ANGELES --
Sepulveda Dam is the western-most of the Corps of Engineers’ dams operated by the Los Angeles District in the Los Angeles County Drainage Area flood control system.
The purpose of the project is to collect flood runoff from the uncontrolled drainage areas upstream, store it temporarily and release it into the Los Angeles River at a rate that does not exceed the downstream channel capacity.
Coordination with our partners includes frequent notification of project conditions. Local entities use this information to evaluate and implement safety measures.
The project has eight outlet passages, of which only four have gates. Because the other four passages have no gates, Sepulveda Dam cannot “shut off” the flow to the LA River. The “standby” position of the gated passages is wide open.
During the initial stages of a flood event, Sepulveda Dam will release as much of the inflow as is physically possible. This minimizes the amount of stored water and the impact to facilities located within the basin. However, as the LA River channel downstream approaches its capacity, the Corps of Engineers begins to close the gates in the gated outlet passages. This results in more water stored in the reservoir, but prevents the escape of the water from the LA River downstream.
The highest water surface elevation ever reached at Sepulveda Dam was 705.10 feet (approximately 37 feet of depth of water or approximately 1,072 acres of land inundated). The dam has never spilled. Water has always been released into the Los Angeles River through the outlet works at a rate that did not exceed the capacity of the downstream channel.
Facilities located within the reservoir basin, such as roads, parks and golf courses, have been allowed into the basin based upon their ability to withstand occasional inundation caused when water is temporarily stored in the reservoir.
Sepulveda Basin does not flood. It holds/retains water, as it is designed to do.
Sepulveda Dam does not spill. It releases water down the Los Angeles River.
Release no. 20-032