Santa Clara Valley Water District (Valley Water) has approved a $1.88bn construction contract to carry out a major seismic retrofit of Anderson Dam, the largest reservoir in Santa Clara County, located in California, US.
The company’s Board of Directors awarded the Anderson Dam Seismic Retrofit Project (ADSRP) contract to the Flatiron Dragados Sukut ADSRP Joint Venture (JV), marking a key stage in a project developed over several years.
Construction on the ADSRP is scheduled to start in early 2027.
The works will involve rebuilding significant portions of the Anderson Dam and its spillway, as well as installing new outlet pipes and undertaking further safety upgrades.
Once completed, the project is expected to restore the reservoir to its full operational capacity.
Valley Water stated that this would improve water supply reliability, bolster groundwater recharge, reduce flood risks and enable the return of recreational activities at Anderson Reservoir and along the Coyote Creek corridor.
Valley Water board chair Tony Estremera said: “Rebuilding Anderson Dam is our top priority. This milestone reflects years of hard work, collaboration and perseverance by our staff, contractors, regulators and community partners.
“Today marks the next phase of one of Santa Clara County's most important water infrastructure projects that will benefit our community for generations to come.”
The project is expected to cost about $2.8bn, making it one of the largest infrastructure undertakings in Valley Water’s history.
Construction is expected to take approximately seven years.
Since 2023, Valley Water has secured over $114m in state and federal grants for regional water infrastructure projects, and continues to seek additional government funding to support the seismic retrofit and manage water rates.
Much of the preparatory work for the main dam project, required to meet regulatory standards and manage water levels safely, is substantially complete.
The Anderson Dam Tunnel Project, designed to upgrade water release capabilities during construction and future emergencies, is nearing completion and is set to be operational this winter.
Anderson Reservoir, built in 1950 and currently restricted to about 3% of its capacity due to seismic concerns, has been the subject of regulatory scrutiny following findings that the dam could become unstable during major earthquakes.
These concerns led authorities to keep the reservoir at reduced levels to mitigate risks until the retrofit is finished.
Valley Water plans to restore the reservoir to full capacity while improving long-term safety and strengthening water-supply reliability for the region’s two million residents.
