Delta Conveyance

An aerial view of the Harvey O. Banks Delta Pumping Plant, the first major plant designed and constructed within the California State Water Project.

An aerial view of the Harvey O. Banks Delta Pumping Plant, the first major plant designed and constructed within the California State Water Project.

What is Delta conveyance?

Delta conveyance refers to State Water Project (SWP) infrastructure in the vast network of waterways comprising the Sacramento-San Joaquin Delta (Delta) that collects and moves fresh affordable water to homes, farms and businesses throughout major regions of the state from the Bay Area to southern California. The Department of Water Resources (DWR) is the owner and operator of the SWP and is responsible for all associated upgrades and maintenance, including the proposed Delta Conveyance Project that will modernize SWP conveyance.

Why is Delta conveyance important?

The Delta is the hub for much of the state’s water supply. Three-fourths of California’s water originates in the Sierra Nevada Mountains as snowpack, eventually flowing through the Delta, where, consistent with water rights, including applicable water quality requirements, it is delivered to more than 27 million Californians and 750,000 acres of farmland. The infrastructure that enables conveyance for California’s primary water supply is critical to the health of local communities and the success of our state’s economy.

 
Cordelia Pumping Plant and Forebay, located between the Putah South Canal and Mangles Blvd. in Fairfield, California.
Cordelia Pumping Plant and Forebay, located between the Putah South Canal and Mangles Blvd. in Fairfield, California.

Why is this project needed?

Because the SWP relies on the Delta’s natural channels to convey water, it is vulnerable to earthquake and sea level rise. According to the United States Geological Survey, there’s a 72% chance of a 6.7 or greater magnitude earthquake occurring in the Bay Area by 2043 that could cause levees in the Delta to fail, crippling the state’s ability to deliver fresh water. As sea levels continue to rise, the Delta will be faced with increasing saltwater intrusion, which threatens fresh water supplies flowing through the Delta. Climate change is also expected to affect the type and timing of precipitation. Certain pumping restrictions in the south Delta can prevent the SWP from reliably capturing water when it is available, especially from storm events. The Project would add new diversions in the north Delta to promote a more resilient and flexible SWP in the face of unstable future conditions.

The best available science demonstrates that these are real, serious threats to California’s primary water supply. We need to take action now to upgrade Delta infrastructure, recognizing that this process will take years to complete improvements. Recent events have also underscored the need to protect public health and safety by taking the appropriate steps now before it’s too late.

View more frequently asked questions related to the Delta Conveyance Project.

Delta Conveyance Updates

Aerial view looking east Holland Tract in foreground then Old river and Bacon Island in background, part of the Sacramento-San Joaquin River Delta in San Joaquin County, California.

DWR continues to advance the Delta Conveyance Project, which is being planned to maintain reliability of the state’s water system in decades to come.

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Aerial view looking east at the S Bacon Island road bridge connecting the Northern end of Bacon Island (Left) and Southern end of Mandeville Island (right),  both part of the Sacramento-San Joaquin River Delta in San Joaquin County, California. Photo taken March 08, 2019.

The California Environmental Quality Act (CEQA) scoping period concluded on April 17, 2020 after an extended 93-day public comment period. DWR is reviewing all submitted comments and will publish a scoping report summarizing the information this summer.

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The Delta

One of the many jobs of the California Department of Water Resources (DWR) is to ensure that its public infrastructure assets—like the State Water Project—are maintained and sustained for the health and well-being of present and future California families.

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