The California Aqueduct East Branch runs into the Mojave Siphon Powerplant, under the Mojave River bed and the Las Flores Valley floor, through the power plant before entering Silverwood Lake. The plant is situated near Silverwood Lake's Cedar Springs Dam in Hesperia, California. Photo taken May 13, 2023. Courtesy of DWR

SACRAMENTO REGION, CA (MPG) - On Dec. 23, the Department of Water Resources (DWR) announced an update to the State Water Project allocation forecast for 2025. The allocation has increased to 15 percent of requested supplies, up from the initial allocation forecast of 5 percent announced in December. The State Water Project provides water to 29 public water agencies that serve 27-million Californians.

Strong storms in late November and early December have helped boost statewide precipitation to just above average for this time of year. Reservoir levels have also increased because of the storms. The initial allocation forecast announced on Dec. 2 had not accounted for these storms because the data was not yet available to water managers. Prior to the second half of November, the start of the water year had been dry and warm.

“The past several weeks has brought welcome rain and snow to Northern California and these improved conditions have allowed the State Water Project to increase the allocation forecast to the benefit of millions of Californians,” said Department of Water Resources Director Karla Nemeth. “While we typically wait to provide an update until January, we felt it important to let our state water contractors know of the increase as soon as possible to allow them to better plan their water supply for the year ahead.”

State water managers will continue to monitor precipitation and snowpack conditions, as well as account for dry soils that might soak up some of the spring runoff following record heat this past summer. Additionally, Southern California remains very dry and has not benefited from the atmospheric rivers experienced so far this season.

“California is still in the early months of our wet season and as recent history has shown, conditions can change quickly,” said Dr. Michael Anderson, state climatologist. “While Northern California has benefitted from early season storms, dry conditions in the new year can leave us with below average totals when warmer weather arrives."

Each year, the Department of Water Resources provides State Water Project allocation forecasts 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 might increase. The next update will likely come this month and will use information from the season’s first snow surveys.

The allocation forecast notice to state water contractors and historical data on State Water Project allocations are available online at water.ca.gov/programs/state-water-project/management/swp-water-contractors.