State Water Project “Flexes” Operations to Capture More Storm Water
An early morning view of the Harvey O. Banks Delta Pumping Plant. The facility is located in Alameda County and lifts State Water Project water 244 feet into the beginning of the California Aqueduct. Photo taken March 28, 2024.
The Department of Water Resources (DWR) is taking advantage of February storms and increased flexibility in new operating permits for the State Water Project to move more stormwater now for use when dry conditions return.
Starting late Monday, the State Water Project increased pumping levels in the Sacramento-San Joaquin Delta from 1,800 cubic feet per second to around 3,000 cubic feet per second in order to move additional storm runoff into storage at San Luis Reservoir. It’s anticipated that this action will capture an additional 16,000 acre-feet of storm water in the reservoir for use later this summer.
The pumping increase is made possible in part by the “storm flex” provisions in the State Water Project’s 2024 federal and state endangered species act permits, which allow for additional diversion of water supply when certain ecological conditions are met during storms. It’s an example of how the new permits foster adaptive management based on real-time conditions to improve water supply availability for millions of Californians and agriculture while still protecting endangered fish species.
Taking advantage of the storm conditions and the “storm flex” provisions also meets Governor Newsom’s January 31 direction to DWR, which operates the State Water Project, to maximize diversion of excess flows to boost the state’s water storage in Northern California, including storage in San Luis Reservoir south of the Delta.
Conditions that allow for activation of the “storm flex” provision in the endangered species permits include low turbidity levels in the central Delta, relatively high San Joaquin River inflows, and the absence of other pumping curtailment triggers tied to the presence of endangered Chinook salmon, Delta smelt, and longfin smelt.
Also on Monday, DWR began releasing water from the main spillway at Lake Oroville under federally required flood control guidelines to maintain flood protection for downstream communities. That water will move through the system, benefiting local water users and the Delta ecosystem. Some of that water will also be captured and moved into San Luis Reservoir.
The State Water Project provides some or all of the water used by 27 million Californians. The project’s main features include Lake Oroville, the California Aqueduct, and San Luis Reservoir in Merced County. The project also supplies water to 750,000 acres of farmland in the Central Valley.