About the Project

Why expand the reservoir?

The Los Vaqueros Reservoir Expansion Project is examining the feasibility of expanding the benefits of the existing reservoir to help serve the water quality and water reliability needs of the Bay Area. The two primary objectives of the Los Vaqueros Reservoir Expansion Project are (1) to develop water supplies for environmental water management and (2) to increase water supply reliability for Bay Area water providers. A secondary objective is to improve the quality of water deliveries to municipal and industrial customers in the San Francisco Bay Area without impairing the project’s ability to meet the environmental and water supply reliability objectives. In addition to the water quality benefits, the Los Vaqueros Reservoir also provides recreation opportunities, flood control benefits, and important terrestrial habitat in the watershed.

How would the project work?

Watch the video below to see the way water moves at Contra Costa Water District currently and how it would move with the planned expansion. With environmental documentation already completed, further expansion of the reservoir is ready to proceed in the near term with commitments from agency partners and funding.

Water Quality

The San Joaquin-Sacramento Delta is a drinking water source for 23 million California residents. Unfortunately, high salt levels and contaminants often impair water quality in the Delta. When the flow of fresh water into the Delta declines in the late summer and fall, drinking water quality degrades. 

Water supplies from the Delta can also be altered or disrupted by regulatory restrictions on pumping, power outages, droughts, and emergencies. The Delta provides important habitat for many species of fish and wildlife, including several threatened and endangered fish species such as winter- and spring-run chinook salmon, steelhead, Delta smelt, and Sacramento splittail. 

Delta fishery resources have declined from historical levels for a variety of reasons, including human activities such as water supply diversions, discharges into the Delta and its tributaries, and loss of habitat.