DWR Announces Initial State Water Project Allocation for 2025

First forecast of the season based on current reservoir storage and impacts of record-setting summer heatwaves

SACRAMENTO, Calif.- Today, the Department of Water Resources (DWR) announced an initial State Water Project (SWP) allocation forecast of five percent of requested supplies for 2025. The SWP provides water to 29 public water agencies that serve 27 million Californians.

The December initial water supply forecast is the first allocation of the new water year and is based on current reservoir storage and conservative assumptions for precipitation to come. For comparison, last year, the initial allocation for Water Year 2024 was 10 percent of requested supplies and it eventually increased to 40 percent by the end of the season.

The initial allocation forecast announced today does not take into account the series of strong storms that brought precipitation to above average across Northern California in the last two weeks of November. These storms will be taken into account along with other variables for future allocation updates. Prior to these storms, the start of the water year had been dry and warm.

"Based on long-range forecasts and the possibility of a La Nina year, the State Water Project is planning for a dry 2025 punctuated by extreme storms like we've seen in late November," said DWR Director Karla Nemeth. "We need to prepare for any scenario, and this early in the season we need to take a conservative approach to managing our water supply. Our wettest months of the season are still to come."

"What we do know is that we started the water year following record heat this summer and in early October that parched the landscape. We must account for dry soils in our State Water Project allocation planning and our runoff forecasts for the spring," Nemeth said.

Soil moisture is critical to the success of California's water years. If the soil is too dry, snowpack runoff in the spring will absorb into the ground instead of providing water supply to the state's reservoirs. The ability to incorporate soil moisture into runoff forecasts is one of many recent improvements for SWP operations. Investments in Forecast Informed Reservoir Operations (FIRO) and improved data collection through DWR's $7 million California Stream Gage Improvement Program will also help DWR and other agencies to incorporate the best available science and data into water management decisions.

Also new this season, the SWP has revised its operating permitto allow for new tools and resources to better manage our water supply for endangered fish species and millions of Californians. Earlier this month, the SWP received a new Incidental Take Permit from the California Department of Fish & Wildlife that covers five species protected under the California Endangered Species Act, including Delta smelt, longfin smelt, white sturgeon, winter-run Chinook salmon and spring-run Chinook salmon. The new permit went into effect on November 4.

Each year, DWR provides the initial SWP allocation based on available water storage, projected water supply, and water demands. Allocations are updated monthly as snowpack, rainfall, and runoff information is assessed, with a final allocation typically determined in May or June. As the winter progresses, if California sees an increase in rain and snowfall, the allocation forecast may increase.

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]