New, nearly $1 billion reservoir in works for South Bay

GILROY, Calif. (KGO) -- With concerns lingering over the next California drought, the Santa Clara Valley Water District is moving ahead with plans to build the largest reservoir in the Bay Area in some two decades east of Gilroy, north of Pacheco Pass Road.

The new reservoir's capacity of 140,000 acre feet is nearly eight times larger than the district's Lexington Reservoir, which is visible near Los Gatos as drivers take Highway 17 across the Santa Cruz mountains between San Jose and Santa Cruz. Lexington is the district's second largest reservoir. The projected cost will be $969 million. About half the money is expected to come from bond funds from the California Water Commission, approved by voters in 2014. Proposition 1 allows bond sales to finance $7.5 billion in water projects. Valley Water will have to cover the remainder. The Commission is expected to make a funding decision by late July.

The 274 acre site along Highway 152 in Santa Clara County has an existing small reservoir, used by local ranchers and farmers and owned by the Pacheco Pass Water District. Valley Water's early plans call for a new dam to be constructed. Water resources would be shared by both water agencies. Valley Water is a wholesale water supplier, serving much of Santa Clara County local water retailers.

The Pacheco Reservoir Expansion Project, as it's identified, will be discussed at the Valley Water board meeting Tuesday evening in San Jose for approval of a memorandum of understanding with the Pacheco Pass Water District and for approval of an option agreement to purchase the land. The new facility will include a 319 foot earthen dam with concrete spillway, a new one-mile tunnel and pipeline to convey water, and a pump station.

We'll be talking to Valley Water board member Gary Kremen about the importance of this long-range project and what it will mean for addressing water needs as Silicon Valley continues to grow in population and density and as drought conditions continue to impact water supplies.