SPI Insights

California – Officials at the Santa Clara Valley Water District are planning the construction of a $1 billion dam and reservoir near Pacheco Pass to serve their 1.9 million Silicon Valley residents and avoid water shortages during future droughts.

A new study from the U.S. Department of the Interior’s Bureau of Reclamation recommends several improvement projects including developing an expanded Pacheco Reservoir and new earthen dam and spillway on the north fork of Pacheco Creek as part of the San Luis Low Point Improvement Project. The dam, which would be 319 feet tall, would replace an existing dam and reservoir on the site, allowing the district to transfer water it stores in the San Luis Reservoir into the new reservoir.

The study suggests alternatives to using the San Luis Reservoir due to algae growth caused by high temperatures and declining water levels. The algal blooms render the water quality there unsuitable for municipal and industrial users.

District officials are working toward a 2024 construction start. The state awarded the district $485 million last year, but officials said they will need an additional $600 million to fund the project that would construct the first new large dam in the Bay Area since 1998.

The project is part of a 5-Year Capital Improvement Program adopted by the district’s board of directors in May. The plan contains 67 capital projects for an estimated cost of $4.4 billion to provide water supply, maintain and improve flood protection infrastructure, and support environmental stewardship.