Dam Safety, North America, Rehabilitation and Repair

California DWR begins Castaic Dam modernization program

As part of a statewide effort in California to reduce seismic and hydrologic risk to State Water Project facilities, the California Department of Water Resources’ Castaic Dam Modernization Program begins this week with an assessment of a stream release structure.

DWR will assess the integrity of a 60-foot-wide rectangular concrete chute used to pass natural flows from Castaic Lake into Castaic Lagoon.

“DWR continues to move forward in the modernization of SWP facilities and will be assessing possible improvements to Castaic Dam to mitigate impacts due to an extreme weather event or earthquake,” said Ted Craddock, DWR Acting State Water Project Deputy Director. “The primary objective for the Castaic Dam Modernization Program is to identify and make improvements that will ensure public safety and a reliable water supply.”

The Castaic Dam Modernization Program also includes seismic retrofits to the inlet tower access bridge, evaluation of the spillway to identify and implement necessary improvements, and earthquake analyses on various dam components.

The planned assessment work will be completed by 2022 and may require drill rigs and other large machinery, DWR says. After completing the assessments, DWR will develop and implement projects to modernize the structures at Castaic Dam.

The SWP is a system of 32 storage facilities, 21 pumping plants, four pumping-generating plants, eight conventional hydroelectric plants and about 700 miles of canals and pipelines. Castaic Lake, completed in 1974 and located 45 miles northwest of Los Angeles, provides regulatory storage, water supply and recreational opportunities.

The modernization program is expected to take about 10 years to complete. Depending on the rehabilitation efforts necessary, Castaic Lake drawdowns may occur for short periods of time.