Valley Water says construction of the Anderson Dam Seismic Retrofit Project is planned to begin in January 2027. District staff will present a schedule update and project details at a public meeting on Nov. 5, 2026, in the Hiram Room of the Morgan Hill Community and Cultural Center at 17000 Monterey Road.

The project page says the Valley Water Board of Directors awarded the construction contract on July 24, 2026, which it called a major milestone in rebuilding the dam.

Why the reservoir is nearly empty

Valley Water says Anderson Reservoir is limited to about 3% of its capacity because of seismic concerns, which costs Santa Clara County valuable drinking water. The retrofit is meant to make the dam safe in a large earthquake and return the reservoir to its original storage capacity. Voters approved the project as part of the Safe, Clean Water and Natural Flood Protection Program.

Wikipedia recounts the history. Anderson Dam was built in 1950 across Coyote Creek east of Morgan Hill and named for Leroy Anderson, a founder and first president of the water district. Studies starting in 2009 raised concerns about how it would hold up in a big quake. In 2016 the district found the dam sits on alluvial deposits that could liquefy and would essentially need to be removed and rebuilt. In February 2020, the Federal Energy Regulatory Commission ordered the reservoir drawn down, and it was drained to about 3% that year.

Work already done

Valley Water lists earlier milestones that prepared the site. Crews finished digging the 24-foot-diameter Low-Level Outlet Tunnel in February 2024 and completed the Diversion Outlet Structure that spring. A micro-tunnel boring machine was launched in August 2024 and retrieved from the reservoir that October. The Coyote Creek North Channel riprap lining and a labyrinth weir were finished at the end of 2024.

Separately, Valley Water says its Live Oak Restoration Reach Project is adding gravel and large wood habitat along about 2,600 feet of Coyote Creek for steelhead trout, with work scheduled from June through December 2026. Nearby residents may see more truck traffic.

The dam matters well beyond Morgan Hill. Wikipedia notes that when the full reservoir spilled during the February 2017 storms, Coyote Creek flooded several San Jose neighborhoods, including Rock Springs and Naglee Park. Calero Reservoir is waiting for its own retrofit until Anderson's is complete.