Bay Delta

South Bay Delta

This view looks northeast from the embankment of the Harvey O. Banks Pumping Plant, toward the intake channel and the Clifton Court Forebay in the distance. DWR/2013.

The Sacramento-San Joaquin Delta plays a major role in California's prosperity by supplying drinking water to almost 27 million residents and fueling a $32 billion agricultural industry. It also serves as important habitat to more than 750 animal and plant species, including more than 40 aquatic species. Our Bay-Delta Office (BDO) ensures water supply reliability and environmental needs are equally met for California.

Water Quality & Supply

We focus on projects and planning that improve water supply reliability and water quality for State and federal water project exports and local uses. We conduct engineering and environmental planning studies to improve the operation of existing State Water Project (SWP) facilities and plan for new facilities. We also: 

  • Improve the understanding of relationships and factors affecting Delta water quality and the effects of water project exports
  • Develop and improve aquatic habitats for Delta animal and plant species
  • Improve conditions for andromonous fish species like salmon
  • Perform environmental planning and regulatory compliance reporting
  • Meet water rights and court decisions requirements

Environmental Compliance

The reliability of water supply from the Delta is at risk due to declining fish species and increasing regulatory requirements to protect remaining populations. Our role is to implement required actions to improve survival of fishery resources in the Delta. It is our goal to reduce the amount of time the Delta water supply is disrupted and improve the Delta ecosystem. We manage projects and scientific studies that are intended to:

  • Improve the efficiency of SWP export facilities in protecting listed fish species
  • Reduce predation and increase survival of listed species at SWP facilities
  • Improve the understanding of the effects of SWP export facilities on listed fish species


We construct and use state-of-the-art mathematical computer models to determine SWP flow of water and water quality in the Delta. These models track water as it falls on land in the form of rain or snow, moves over land as streams and rivers, is then stored in reservoirs or in the ground, and finally makes its way back out to the ocean or evaporates into the atmosphere.

Our models track the quality of water and any salts or heavy metals that move with the flow of water, including the effects of sea water intrusion in the Delta. The models can also determine impacts to water supply and quality over the long term by evaluating the impact of water management strategies and alternatives.


Map of the Sacramento-San Joaquin Delta. Please contact (916) 653-1099 for more information.

The Sacramento-San Joaquin Delta.