print Font Size: small font medium font large font

C1: Anderson Dam Seismic Retrofit

Anderson Reservoir is currently limited to 68 percent of its capacity due to seismic concerns, costing Santa Clara County valuable drinking water resources. This project covers earthquake retrofitting of Anderson Dam to improve reliability and safety, and returns the reservoir to its original storage capacity.

Anderson Dam creates the county’s largest surface water reservoir—Anderson Reservoir—which stores local rainfall runoff and imported water from the Central Valley Project. The reservoir is an important water source for treatment plants and the recharge of the groundwater basin. Besides restoring drinking water supplies, the upgrade also supports compliance with environmental regulations. The district’s regular reservoir releases ensure that downstream habitat has healthy flows and temperatures to sustain wildlife.

A breach of Anderson Dam at full capacity could have catastrophic consequences, including inundation of surrounding land more than 30 miles northwest to San Francisco Bay, and more than 40 miles southeast to Monterey Bay.


  • Brings the dam into compliance with today’s seismic standards
  • Increases reliability and safety of our area’s largest reservoir by protecting it from earthquakes
  • Eliminates operational restrictions issued by the state Division of Safety of Dams which would restore Anderson Reservoir to its full capacity of approximately 30 billion gallons, regaining 32 percent or 9.3 billion gallons of water storage for our current and future supply
  • Ensures compliance with environmental laws requiring reservoir releases that maintain appropriate flows and temperatures to support downstream wildlife habitat
  • Minimizes the risk of uncontrollable releases from the reservoir which could cause downstream flooding

Project Status

(As of April 2016)

  1. Planning Phase and Planning Study Report have been completed.
  2. Phase 1 geotechnical investigations for the design phase have been completed.
  3. Phase 2 geotechnical investigations for the design phase are expected to be completed in Spring 2016.
  4. The Draft EIR document is slated to be released for public review in Summer 2016



Key Performance Indicator

  1. Provide portion of funds, up to $45 million, to help restore full operating reservoir capacity of 90,373 acre-feet



Priority C-200

Project Information

Project StartFY 2014
Project FinishFY 2020
Safe Clean Water
Program funding

$66.1 M**

(2015 Dollars)

**More financial information: 5-Year Implementation Plan, pages: 19-27

For more information: