California Construction News staff writer
Valley Water has awarded a $1.88 billion construction contract for the Anderson Dam Seismic Retrofit Project, marking a major milestone in a long-planned effort to rebuild the county’s largest reservoir and strengthen the region’s water infrastructure.
The Valley Water Board of Directors approved the contract July 24, clearing the way for construction to begin in early 2027. The work will include rebuilding most of Anderson Dam and its spillway, installing new outlet pipes and completing seismic safety upgrades.
The contract was awarded to Flatiron Dragados Sukut ADSRP Joint Venture. The overall project is expected to cost about $2.8 billion and take seven years to complete.
When finished, Anderson Reservoir will return to full operating capacity, improving water supply reliability, supporting groundwater recharge, reducing flood risk and restoring recreation at the reservoir and along the Coyote Creek corridor.
“Rebuilding Anderson Dam is our top priority,” Valley Water Board Chair Tony Estremera said in a statement. “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.”
Built in 1950, Anderson Reservoir is the largest of Valley Water’s 10 reservoirs and has enough capacity to hold all of the agency’s other reservoirs combined.
The contract award follows years of planning, engineering, environmental review and regulatory approvals. Valley Water said most of the supporting projects needed to prepare the site and manage flows in Coyote Creek during construction have been completed.
The Anderson Dam Tunnel Project, considered the centerpiece of the preparatory work, is in its final stages and is expected to be completed later this year. The project replaces the dam’s 4-foot-diameter outlet pipe with a new 13-foot-diameter tunnel that will allow larger releases into Coyote Creek during construction and improve reservoir management during storms and emergencies. The tunnel is expected to be operational this winter.
Valley Water said it is on track to complete all five supporting projects before major reconstruction begins, allowing Anderson Reservoir to remain empty while the new dam is under construction.
Since 2023, the agency has secured more than $114 million in state and federal grants for water infrastructure projects in Santa Clara County and continues to seek additional funding for the Anderson Dam Seismic Retrofit Project to help keep water rates affordable.
