California makes big increase to state water allocations

California’s torrential storms from late December through early January will allow the State Water Project to deliver nearly 1.3 million acre-feet of water throughout the state this year – six times as much as projected before the storms, state water officials said.

Entrenched in a third consecutive year of severe drought conditions, the California Department of Water Resources on Dec. 1 announced it would be able to deliver only 5% of water supply requested for 2023. The State Water Project stores and delivers water to 29 water agencies that serve 27 million Californians.

But now, the state says the project can deliver 30% this year. That works out to 1.27 million acre-feet of water, about 413 billion gallons.

“The allocation increase is the direct result of extreme weather in late December and nine atmospheric rivers in early January that helped fill reservoirs and dramatically increase the Sierra Nevada snowpack,” the California Department of Water Resources wrote in a Thursday news release.

A series of nine atmospheric river storms struck California between late December and the first half of January. The storms produced dangerous flooding, killing at least 22 people, and brought extreme winds causing extensive damage and cutting power to hundreds of thousands.

But the downpours and heavy mountain snow also replenished withered reservoirs and boosted California’s snowpack levels past double their historic averages for this time of year.

The allocation increase is “largely derived from improvements to reservoir supplies,” Karla Nemeth, director of the Department of Water Resources, said during a virtual news conference Thursday afternoon.

California’s two largest reservoirs included in the State Water Project, Lake Oroville and the San Luis Reservoir, gained a combined 1.62 million acre-feet of water during the recent storms, state water officials said in Thursday’s news release, which is “roughly enough to provide water to 5.6 million households for a year.”

Nemeth said the state is not yet taking snowpack calculations into consideration in State Water Project allocations, but will begin to do so following California’s next snow survey, which is scheduled for Wednesday and will represent the state’s first monthly snowpack report since the bulk of the winter storms.