California's Water:'Beyond Drought: Factors Affecting California's Water Supply'
We usually think of rain and snow as the main factors determining how much water is available to California’s cities, farms and businesses each year. But other variables can affect water availability, especially when it comes to the ecologically sensitive hub of our state’s water system, the Sacramento-San Joaquin Delta.
This segment of “California’s Water” focuses on a recent crisis involving a threatened Delta fish as an example of how factors other than precipitation come into play. Visits to San Luis Reservoir, a Delta fish conservation facility and areas served by the state’s water system help tell the story.
Background
The Sacramento-San Joaquin River Delta is the hub of the state’s water supply system and home to a unique ecosystem. It has been in the headlines lately because of a crisis involving the threatened Delta smelt, a minnow-like fish that has been listed as threatened since 1993, and the pumps that supply water to more than 25 million Californians and more than 7 million acres of farmland.
The most recent chapter in the crisis played out Aug. 31 when a U.S. District Court Judge Oliver Wanger ordered the State Water Project and federal Central Valley Project to reduce pumping in the Delta to protect the smelt. The ruling translates into an average loss of as much as one-third of previously available water supplies, depending on year type.
Earlier this spring, the decline of the smelt caused biologists to fear that it may be on the brink of extinction. In response, the state Department of Water Resources voluntarily shut down the pumps that send water from the Delta to parts of the Bay Area, Central Valley and Southern California for 10 days in June. Further curtailments are likely in the coming months.
Effects of the Shutdown
This segment of “California’s Water” focuses on the earlier crisis as an example of how factors other than precipitation come into play. Visits to San Luis Reservoir, a Delta fish conservation facility and areas served by the state’s water system help tell the story.
The crisis shows that when it comes to water, one action can ripple across many regions of the state. Uncertainty over Delta pumping is creating challenges for many local water agencies, with potentially significant water supply cutbacks ahead if curtailments occur.
During the 10-day shutdown, areas that rely on water from the Delta were compelled to use groundwater, emergency reserves or other alternative supplies. Some agencies, such as Alameda County Zone 7 Water Agency, asked their customers to reduce water use and have extended that call through the end of 2007.
Kern County Water Agency, which receives water from the Delta via the State Water Project, declared a local drought emergency, citing reduced water supplies and crop losses.
Also during the shutdown, San Luis Reservoir near Los Banos was drawn down to very low levels in order to continue to supply water to the Bay Area, Central Valley and Southern California. The reservoir level dropped two feet a day, raising concerns about the structural integrity of the exposed earthen banks of the reservoir.