- March storms boosted California’s water supply outlook.
- State Water Project allocation rose from 35% to 40%.
- Oroville storage now at 86% capacity and above average.
Wednesday, March 26, 2025 — The California Department of Water Resources (DWR) announced yesterday that March storms have allowed it to increase 2025 deliveries
from the State Water Project (SWP) to 40% of requested supplies. This is up from last month’s 35% allocation and reflects improved snowpack, rainfall, and reservoir conditions.
The SWP is a key source of water for 27 million people and 750,000 acres of farmland across the state. Yesterday’s update comes just ahead of the April 1 snow survey, which traditionally marks the peak of Sierra Nevada snowpack.
“As we near the end of the wet season, our focus shifts to snowpack runoff and whether temperatures allow for a slow melt so we can capture as much of that runoff as possible,” said DWR Director Karla Nemeth. “Despite periods of extremely dry conditions this season, water managers have been able to effectively capture, move, and store water for use later this year while also maintaining flood protection.”
Oroville and San Luis Reservoirs See Gains.
Lake Oroville, the SWP’s largest reservoir, has reached 86% of its total capacity and is holding 121% of its historical average for this time of year. Storage at San Luis Reservoir in Merced County is also near full for the SWP’s share.
DWR noted it has been carefully managing Lake Oroville (pictured above) releases to balance water storage and flood control. As spring advances and flood risks subside, there may be opportunities to increase storage even further.
Environmental and Infrastructure Considerations.
The agency highlighted the ecological importance of the upcoming months in the Sacramento–San Joaquin Delta. SWP operations will be scaled back in April and May to protect endangered fish species. Releases from Lake Oroville to support water quality and habitat may also be required, depending on weather and runoff conditions.
These constraints, DWR noted, illustrate the need for additional water infrastructure. The department pointed to the proposed Sites Reservoir and Delta Conveyance Project as examples. According to DWR, the Delta Conveyance Project alone “could have captured more than 750,000 acre-feet of additional water supply this winter,” which it said “would have translated to a 20 percent increase in the current State Water Project allocation, on top of the increase announced today.”
What’s Next for Water Deliveries.
SWP allocation forecasts are updated monthly through the spring, with the final allocation typically set in May or June. Future increases will depend largely on how much water the Sierra Nevada snowpack ultimately releases as it melts.
Additional information on SWP allocations and how the process works can be found on the DWR website:
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