State Water Project Allocation Increases Heading into Summer Months

SACRAMENTO, Calif. - Today, the Department of Water Resources (DWR) announced an increase to the State Water Project (SWP) allocation for 2026. The allocation is now 45 percent of requested supplies, up from the previous allocation of 30 percent announced on January 29. The allocation establishes how much water the State plans to deliver to the 29 public water agencies served by the SWP, which provides water to 27 million Californians and 750,000 acres of farmland.

In the spring, SWP allocations are based on current hydrological conditions, existing reservoir storage, and remaining snowpack. While California saw record heat in March and early snowmelt, consistent rainstorms in April provided critical runoff through the system that allowed DWR to capture more water and meet environmental regulations without using stored water. Currently, the SWP's largest reservoir, Lake Oroville, is at 99 percent of capacity. Statewide, reservoirs are 117 percent of average for this time of year.

The challenge remains that California's snowpack, the state's frozen reservoir, is essentially gone. As of today, the statewide snowpack is just 12 percent of average. The snowpack peaked in mid-February and has since melted off.

"California's reservoirs are full, but most snowpack melted off weeks ago. We must use this stored water carefully because there's no backfill until next season," said DWR Director Karla Nemeth.

Learn more about how snowmelt impacts State Water Project allocations: https://youtu.be/vXdP6s8Kq0E.

The SWP utilized real-time operational flexibility to benefit water users and the environment despite the fact that so much of this year's precipitation came as rain instead of snow. Water managers at Lake Oroville coordinated closely with the U.S. Army Corps of Engineers to capture as much water as possible while still providing flood protection to downstream communities. These flexible operations, coupled with the improved runoff in the system resulted in an additional 400,000 acre-feet of storage in Lake Oroville. This puts the SWP in a better position to provide water supply to contractors this year while maintaining robust carryover storage to meet water supply and environmental needs should next year be dry.

Each year, DWR provides an initial SWP allocation in December based on available water storage, projected water supply and water demands. Allocations are updated monthly as snowpack, rainfall and runoff data is analyzed, with a final allocation typically determined near the end of the season in May or June. This season, the initial allocation was 10 percent on December 1, updated to 30 percent on January 29, and increased to 45 percent today.

Historical data on SWP allocations is available at https://water.ca.gov/programs/state-water-project/management/swp-water-contractors.

Contact:
Ryan Endean, Public Affairs, Department of Water Resources

[email protected]