The Department of Water Resources (DWR) increased the 2011 State Water Project (SWP) water allocation to 80 percent of contractors’ requests, up 30 percent from last year’s final allocation.
“This is very good news,” said DWR Director Mark Cowin. “Near-record precipitation and water content in our mountain snowpack have given us a good supply year. We should not forget, however, that this state can slip back toward drought conditions any given year and conservation needs to be a lifelong habit.”
This year’s allocation is 3,337,701 acre-feet. In 2010, the State Water Project delivered 2.086,000 acre-feet, 50 percent of a requested 4,172,126 acre-feet, up from a record-low initial projection of 5 percent due to lingering effects of the 2007-2009 drought.
Many local agencies are taking steps to improve their ability to store water during wet periods. This year serves as an example of how enhanced local groundwater and surface water storage could allow for additional deliveries during short term high flow conditions and thereby improve local water supply reliability.
Precipitation to date is over 116 percent of average for the water year (October 1-September 30). Runoff into streams and reservoirs is 165 percent of average.
Statewide, snowpack water content is 167 percent of average for the date and 152 percent of the average, April 1 seasonal total. Most of California’s major reservoirs are above average levels for the date despite making flood control releases to make room for inflow from melting snow this spring and summer.
Lake Oroville in Butte County, the State Water Project's principal reservoir with a capacity of 3.5 million acre-feet, is at 109 percent of normal storage for the date. It currently is holding 3,126,941 acre-feet, 88 percent of its capacity. Lake Shasta north of Redding, the federal Central Valley Project's largest reservoir with a capacity of 4.5 million acre feet, is at 103 percent of normal storage for the date, also at 88 percent of its capacity.
The State Water Project delivers water to more than 25 million Californians and nearly a million acres of farmland.
Projections of SWP deliveries are adjusted through the winter and early spring as hydrologic conditions develop. DWR is conservative in its projections since farmers and others can suffer if expected amounts cannot be delivered.
DWR's first estimate for 2011 was that it would be able to deliver 25 percent of requests.
SWP deliveries were 60 percent of requests in 2007, 35 percent in 2008, and 40 percent in 2009.
The last 100 percent allocation – difficult to achieve even in wet years because of pumping restrictions to protect threatened and endangered fish – was in 2006.