map of northern california water source

Reducing Reliance on The Bay-Delta

The Sacramento-San Joaquin Bay-Delta is a network of islands and waterways at the confluence of the Sacramento and San Joaquin rivers east of San Francisco Bay. The Bay-Delta is also the hub of the State Water Project, a water storage and delivery system stretching over 700 miles from Lake Oroville in Butte County to its termination at Lake Perris in Riverside County. The State Water Project is owned by the State of California and operated by the California Department of Water Resources. Water from the Bay-Delta comes to the San Diego region via the State Water Project through the Metropolitan Water District of Southern California.

The Water Authority has a long history of supporting efforts to address the Bay-Delta’s complex environmental and water supply challenges. While water from the Bay-Delta is a critical resource for more than 25 million Californians, San Diego County is doing their part by reducing reliance on it.

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linkCalifornia Department of Water Resources Site download this documentBay Delta Factsheet

Water Resilience Portfolio

The Water Authority’s only source of Bay-Delta water is through its water purchases from MWD, which have decreased over the past three decades through the Water Authority and its member agencies’ long-term efforts to diversify the region’s water supply portfolio. Today, the San Diego region receives very little water from the Bay-Delta and will continue to reduce its reliance on it. Reducing pressure on the Bay-Delta aligns with state law designed to balance the environmental and water supply functions of the estuary.

State Policy
sunset over the baydelta

Delta Reform Act

The Water Authority supported the 2009 Delta Reform Act, which established the state’s co-equal goals of water supply reliability and ecosystem restoration in the Bay-Delta. The Delta Reform Act made reducing dependence on the Bay-Delta while improving regional self-sufficiency an imperative, but the Water Authority began implementing these actions many years before they were required by state law. The San Diego region has since significantly increased its water use efficiency ethic.

Executive Order N-10-19

In April 2019, Governor Gavin Newsom issued Executive Order N-10-19, directing his administration to “identify and assess a suite of complementary actions to ensure safe and resilient water supplies, flood protection and healthy waterways for the state’s communities, economy and environment.” Newsom then directed state agencies to scrap the previous administration’s plans for a twin-tunnel project in the Bay-Delta in favor of a one-tunnel system.

Board Support

In July 2019, the Water Authority’s Board of Directors unanimously supported Governor Gavin Newsom’s efforts to develop a water resilience portfolio approach that meets the needs of California’s communities, economy and environment through the 21st century. In addition to focusing on multi-benefit approaches that meet many needs at once, the portfolio advances a single-tunnel project to transfer water across the Bay-Delta. The Water Authority Board supports the single-tunnel proposal contingent on a project financing plan that treats San Diego County ratepayers fairly through the proper allocation of project costs as supply charges.

Water Authority History

A Vision Since 2013

Recognizing its importance, the Water Authority has a long history engaging in assessments of a variety of potential solutions to complex ecological and water supply issues in the Bay-Delta. Newsom’s portfolio approach is similar to a proposal the Water Authority, along with several water districts statewide, the Natural Resources Defense Council and other conservation groups proposed as a Portfolio Alternative for the Bay-Delta in 2013. That proposal included a single tunnel, new water storage south of the Delta and significant investments in local and regional water supplies.

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