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History/Background
Sacramento-San Joaquin Delta Summary: Policies & Principles, October, 2007 (15KB pdf)*
Overview: In Search of a Permanent Solution
As the largest estuary on the West Coast, the Sacramento-San Joaquin Delta spans a watershed that captures more than half of California's surface water. It is where the rivers of the Sierra Nevada meet the tidal influences of San Francisco Bay. Two of every three Californians depend on the Delta as a key water source, from Solano County to the north of the Delta to hundreds of miles southward in San Diego. Millions of acres of farmland in the Central Valley depend on the Delta as well. So do millions of birds that use the estuary for migration patterns, and numerous fish species including salmon and steelhead.
The Delta is as key to the California economy as it is to the environment. But today the Delta struggles to fulfill these vital missions as it faces numerous stresses. Non-native species such as Asian clams have taken hold and consume much of a key food supply for other fish. Islands that have been transformed from marshlands to farmlands produce less food for Delta fish as well. Pesticide runoff harms the fisheries. And operations of water pumps can alter flows in the Delta.
The pumps of the Central Valley Project and State Water Project (the source for Metropolitan via the California Aqueduct) are in the southern part of the Delta, while most of the water originates from the north, on the Sacramento River. Moving these water supplies through the Delta can create conflicts with natural flow patterns. All told, the mounting stresses have prompted pumping restrictions to curtail as much as 25 percent of traditional water supplies.
The Delta is also at risk because of its levee system. Hundreds of miles of substandard levees protect islands that have receded to below the Delta water level. Were the levees to fail, Delta islands would be quickly submerged. Seismologists have grown increasingly concerned about the potential for an earthquake to collapse numerous levees and cause salty water from San Francisco Bay to take hold in the Delta. Were this to happen, the Delta would no longer be a drinkable water supply. Seismologists predict that there is a two-thirds chance in the coming decades that a large enough earthquake to cause such a scenario is likely to happen.
For Metropolitan, the challenges in the Delta mean that in an average rain year, the district can no longer replenish groundwater supplies and set aside reserves for dry years, absent dramatic new conservation by 19 million residents or the purchases of additional supplies.
Efforts are under way to address the many problems of the Delta. The centerpiece of the planning efforts is the Delta Conservation Plan. The state and federal agencies responsible for wildlife regulation and water operations are leading this process to identify a combination of ecosystem and water system improvements. The goal is to approve a 50-year adaptive management plan consistent with endangered species laws. In its historic package of 2009 Delta reforms, the California Legislature required BDCP to meet the highest environmental standard in the country, a Natural Communities Conservation Plan. This state environmental planning statute seeks to develop habitat restoration strategies that can lead to the recovery of threatened and endangered species. Another key component of the Delta legislation was the creation of a new governing entity, the Delta Stewardship Council, that seeks to coordinate the actions of local, state and federal agencies through the development of a comprehensive Delta Plan. The Stewardship Council began its work in the spring of 2010.
Delta Conservation Plan
Delta Vision
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