The San Francisco Bay Area depends on the Delta watershed for 2/3 of its drinking water supply. Sierra Nevada snowmelt and rainfall fills rivers and streams that flow toward the San Francisco Bay. Much of that mountain water flows through the Sacramento-San Joaquin River Delta to communities throughout the Bay Area.
In fact, 40 percent of Santa Clara County's water supply is conveyed through the Delta.
The Delta is an essential feature of our water system. Yet, after decades of alterations, the Delta is far from the natural estuary it once was. Loss of habitat, proliferation of invasive species, predation, and water operations have resulted in population declines of several native fish species. This has led to increasing regulatory restrictions that have decreased Delta exports over the past several decades in order to protect fish. Delta water supplies are also at risk from increased salinity intrusion due to climate change, including sea level rise, and seismic threats to its fragile levee system.
Without an effective conservation and renewal strategy, the Delta’s sensitive ecosystem and water transport system will continue to deteriorate, threatening the delivery of safe, reliable drinking water to the nearly 1.8 million residents that we serve in Silicon Valley. To sustain our economy and our way of life, we must find a balanced solution that restores the Delta ecosystem and assures long-term sustainable water supplies.
Beginning in 2006, the statewide Bay Delta Conservation Plan (BDCP) effort has attempted to achieve the co-equal goals of water supply reliability and ecosystem restoration for the Delta. .
In April of 2015 state and federal officials announced a new alternative to the existing Bay-Delta Conservation Plan. Alternative 4a (California WaterFix) reflects the state’s proposal to now separate a cross-delta conveyance facility and habitat restoration (California EcoRestore) into two separate efforts.