Crews install piezometers on the gated spilway for the Pyramid Dam Modernization project in Los Angeles County. DWR/2019

The Department of Water Resources (DWR) recently announced it is moving forward with the modernization of State Water Project (SWP) facilities across the state to reduce seismic and hydrologic risks. Several projects across California have begun.

The projects represent a significant investment by the State to address these risks to California’s water infrastructure. “Earthquakes are a constant threat to our infrastructure, and we need to make our facilities as resilient as possible,” cautioned Ted Craddock, Acting SWP Deputy Director. DWR says it will continue to identify and make improvements to SWP facilities in 2020 to ensure public safety and a reliable water supply.

Here are some of the current projects in Southern California:

Perris Dam Seismic Retrofit, Riverside Co. DWR began retrofit work last October on the Outlet Tower Bridge, a component of the Perris Dam Complex. The second of three seismic retrofit projects, this work includes modifications to the bridge support and seat, and the installation of stiffener plates. Constructed from 1970 to 1974, Perris Dam is identified as a high priority state-owned dam due to its proximity to nearby earthquake faults and large downstream communities. This retrofit phase, planned for completion by fall 2020, will ensure the tower bridge can withstand a major earthquake and ensure access to valve controls for release of water under normal and emergency operations.

Pyramid Dam Modernization Program, LA Co. DWR began the project in September 2019 with assessments on the condition of the facility and possible improvements to the emergency and gated spillways. The gated spillway is used once per year on average and the emergency spillway has never been used to date. Pyramid Dam and Lake are located about 60 miles northwest of downtown Los Angeles and provide water storage for the greater LA area. The dam was built between 1969 and 1973 and was recently rated as satisfactory, meaning that although there are no existing safety deficiencies, improvements could be made to mitigate the impacts of earthquakes or extreme weather events. Over the next several years, DWR will conduct assessments and undertake construction activities to ensure the dam continues to function safely. Field investigations will be completed in early 2020 and evaluations are planned for completion in 2022.

Castaic Dam Modernization Program, LA Co. Assessments have begun on the integrity of a 60-foot-wide rectangular concrete chute that is used to pass natural flows from Castaic Lake into Castaic Lagoon. Located 45 miles northwest of Los Angeles, Castaic Dam, Lake, and Lagoon also provide water for the greater LA area. The dam was built between 1965 and 1974 and was reported in fair condition after its most recent inspection, meaning that improvements could be made to prevent serious impacts after an extreme weather or earthquake event. DWR will conduct additional assessments of the dam, spillway, intake towers, and other associated structures to ensure that the dam continues to operate safely and reliably. The modernization efforts of the dam facility are expected to take about 10 years.

Source: CA DWR