EBMUD and the Delta

The Sacramento - San Joaquin River Delta is an extensive inland estuary that supports about 500 different plant and animal species and provides drinking water for 3 million Bay Area residents and 22 million Southern Californians. The Delta ecosystem has been in a serious decline for a number of decades. The South Delta pumps that provide irrigation and drinking water supplies are widely believed to be a significant contributor to the Delta ecosystem collapse.

Though EBMUD does not deliver Delta water to customers, we rely on a healthy Delta ecosystem and a safe water supply. EBMUD and our East Bay customers depend mostly on the Mokelumne River, a small Delta tributary that originates in the Sierras, for nearly all of our drinking water supply. Water travels 90 miles from EBMUD’s Pardee Reservoir to the East Bay via three large aqueducts. Fifteen miles of the aqueducts cross the fragile Delta, where the large pipes are vulnerable to flooding and earthquakes.

In addition to EBMUD’s water supply and infrastructure interests in the Delta, EBMUD also owns a steelhead and salmon hatchery on the Mokelumne River and is responsible for maintaining downstream flows on the river to optimize ecosystem habitats.

Our Commitment to the Delta

  • Infrastructure: EBMUD, in partnership with local interests, has invested over $20 million to strengthen the levees that protect critical infrastructure, including EBMUD’s water lifelines – the Mokelumne Aqueducts. EBMUD has also invested $40 million to strengthen the aqueducts to help withstand seismic activity.

  • Environment: The health of the Delta is critical for Mokelumne fish that migrate through the Delta. Operation of the South Delta water diversions and pumps impact Delta flow patterns and affect salmon and steelhead migration to and from the ocean. EBMUD has worked cooperatively with the State and Federal regulatory agencies to develop and implement a flow agreement that protects Mokelumne fish. Under the agreement, the Mokelumne contributes proportionate flows into the Delta. More details about salmon in the Mokelumne River are available. For additional information contact Lodi Fisheries & Wildlife 209-263-6350 or view fisheries reports.


Alice Towey, Environmental Affairs Officer
Phone: 510-287-1105

Document Type Size
EBMUD Delta Principles PDF <1 MB
EBMUD Water Supply and the Delta Map PDF <1 MB