The San Clemente Dam Removal Project’s second construction season begins in May, starting with the final drawdown and draining of the water behind the dam. The project’s three-year construction schedule began last summer and is on track for completion next year. This is the largest dam-removal project in California history.
San Clemente Dam is a 106-foot-high concrete arch dam located 18 miles upstream from the Pacific Ocean on the Carmel River in Monterey County. In 1991, the Division of Safety of Dams within the California Department of Water Resources (CDWR) agreed with California American Water’s (CAW) determination that the San Clemente Dam was inadequate for seismic stability and flood safety. After years of study, the CDWR and Army Corps of Engineers evaluated five options to address the safety issues.
The option to remove the dam and reroute the river around silt that had accumulated behind the dam was favored by environmental groups and public agencies concerned with protecting and enhancing the Carmel River ecosystem. The project involves an innovative engineering approach to reroute a half-mile portion of the Carmel River into San Clemente Creek and use the abandoned area for sediment storage.
“About 175 people will be directly employed for the project this summer, in addition to numerous outside vendors and suppliers,” said CAW President Rob MacLean. “All that activity translates into approximately $150 million of economic output for the area. We’re proud to be partners in this project, which benefits the environment, public safety and the local economy.”
Construction activities completed last year included developing a new access road, preparing the 68-acre construction site, partially constructing the Carmel River diversion system, completing geotechnical investigations and relocating fish and other wildlife. Work to be completed this year will include permanently rerouting the Carmel River course to bypass 2.5 million cubic yards of accumulated sediment behind the dam and start the removal of the dam. Next summer, the dam will be fully removed, and the natural character and habitat of the project site will be restored.