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Surface Storage Investigations

Los Vaqueros Expansion Investigation
Los Vaqueros Reservoir Area
The Los Vaqueros Expansion Investigation follows the new era approach to project formulation by emphasizing environmental water management  uses, as well as, municipal water supply reliability and quality.  The existing Los Vaqueros Reservoir would be expanded up to a total of 275 thousand acre-feet to take full advantage of the existing state of the art fish screens currently in use in the Delta.  These fish screens have proven effective at protecting Delta Smelt, Longfin Smelt, and other species of concern from the effects of water pumping from the Delta.  
DWR, The Bureau of Reclamation, and Contra Costa Water District (CCWD) are collaborating with local, State, and Federal agencies and stakeholders on the formulation and development of this project.   The existing Los Vaqueros Reservoir was completed in 1997 to provide 100 TAF of offstream water storage to improve water quality and provide emergency storage for CCWD customers. Water stored in Los Vaqueros Reservoir is diverted from the Delta at the existing Old River Pump Station when Delta water quality is good and impact to Delta fisheries is low.  New Delta intakes, pumps, and pipelines would be required to fill the additional reservoir capacity, and water deliveries would be made from the expanded reservoir to Bay Area beneficiaries through new conveyance facilities.

Planning Objectives

The Los Vaqueros Expansion Investigation objectives are to use an expanded Los Vaqueros Reservoir system to:


Primary Objectives:

  • Develop water supplies for environmental water management that supports fish protection, habitat management, and other environmental water needs.
  • Increase water supply reliability for water providers within the San Francisco Bay Area, to help meet municipal and industrial water demands during drought periods and emergencies or to address shortages due to regulatory and environmental restrictions.

Secondary Objectives:

  • 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 stated above.


The Los Vaqueros Expansion Investigation is taking a two step approach.   The CCWD Board certified a Final EIR and approved an expansion from 100 TAF to 160 TAF on March 31, 2010. CCWD has completed design and is moving forward with construction scheduled to begin in 2011. With additional funding, local, state, and federal partners may choose to continue to study the feasibility of a 275 TAF expansion alternative in the context of other Delta initiatives to improve Delta conveyance and better protect Delta fisheries, including long-term programs being explored in the BDCP.


General Schedule

View the CCWD Board agenda here.



For more information about this project, documents, and upcoming public hearings, go to or


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