Tuesday July 7, 2026
DWR —
The people who operate the State Water Project move water within a realm of regulations designed to protect water quality and endangered fish species under various conditions throughout the year. Starting July 1, those regulations make a big shift.
This annual change in regulations is driven primarily by what scientists know about the life cycles and movements of native fish species that include Delta smelt, longfin smelt, steelhead, and Chinook salmon. At the onset of summer, around July 1, these threatened and endangered species generally have moved well beyond the south Delta channels that are influenced by the pumping of the State Water Project (SWP). Starting July 1, state and federal regulations allow the SWP to capture and move water supply at a faster rate than February through June, when native fish species are spawning or migrating through the Delta and could be harmed by SWP pumping.
In anticipation of the onset of summer regulations, the California Department of Water Resources (DWR), which operates the SWP, started releasing more water from Lake Oroville, 150 miles upstream of the Delta. Pumping in the Delta is expected to increase from 1,000 cubic feet per second (cfs) on June 30 to about 6,500 cfs by July 5. The pumped water will either flow 70 miles south into storage at San Luis Reservoir, to be used later by Santa Clara Valley, San Joaquin Valley and southern and coastal water districts, or it will flow directly to these water districts to meet their immediate needs. In all, the SWP meets some or all of the water needs of 27 million Californians.