DWR Releases 2011 Report on SWP Reliability

The Department of Water Resources has released the 2011 State Water Project (SWP) Delivery Reliability Report.

The latest in a series of reports on the delivery reliability of the SWP, the document updates estimates of current (2011) and future (through 2031) SWP deliveries, taking into account pumping restraints to protect Delta smelt, salmon, and other fish species as well as variations in precipitation and impacts of climate change.

In an introductory message, DWR Director Mark Cowin said the report shows the SWP continues to be subject to reductions in deliveries due to operational restrictions under biological opinions issued in 2009 and 2009 to protect species. Though federal court decisions have remanded the biological opinions to fish agencies for further review and analysis, the operational rules continue to be legally required.

Findings presented in the report are designed to assist water planners and managers in updating their water management and infrastructure development plans, he wrote.

“These results emphasize the need for local agencies to develop a resilient and robust water supply, and a distribution and management system to maximize the efficient use of our variable supply,” Cowin wrote. “They also illustrate the urgent need to improve the method of conveying water past the Delta in a more sustainable manner that meets the dual goals of increasing water delivery reliability and improving conditions for endangered and threatened fish species.”

The report notes that population growth and recent-year legislation on water conservation are among key factors underscoring the importance of accurately assessing the SWP’s reliability of deliveries.

The SWP provides at least some of the water consumed by 25 million Californians and used to irrigate about 750,000 farmland acres. About 70% of the project’s deliveries goes to urban areas, while about 30% goes to farms.

This year’s report includes information on the history of the SWP and additional details on facilities and operations. A new chapter also focuses specifically on SWP exports at the system’s Harvey O. Banks Pumping Plant in the Delta. 

The 2011 State Water Project Delivery Reliability Report is available here.