Last month, the Department of Water Resources (DWR) announced a further increase in the State Water Project (SWP) water supply allocation forecast for 2024. The forecasted allocation has increased to 40 percent, up from 30 percent last month. The State Water Project provides critical water supplies to 27 million Californians and farmers served by 29 public water agencies. Today’s increase would provide an additional 420,000 acre-feet of water, enough water to serve an estimated 1.5 million households for a year.
Last month's allocation update is based on an 800,000 acre-foot increase in storage at Lake Oroville and the latest snow survey data from the all-important April 1 measurements. April 1 is typically when California sees peak snowpack and the start of the snowmelt season. Statewide, the snowpack remains near average at 99 percent of average for this date. The spring forecast in the latest snow runoff report, known as Bulletin 120, also anticipates above average runoff this spring.
The State Water Project is working with the U.S. Army Corp of Engineers to manage flood releases and maximize the capture and storage of water from the winter storms and spring runoff in its reservoirs. Since January 1, storage has increased by 917,000 acre-feet at Lake Oroville and by 178,125 acre-feet at San Luis Reservoir. Oroville is currently at 124 percent of average and 94 percent of capacity and is expected to reach capacity next month.
During the spring, the ability to move water supply south through the system will continue to be impacted by the presence of threatened and endangered fish species near the State Water Project pumping facility in the south Delta. The presence of these fish species has triggered state and federal regulations that significantly reduce the pumping from the Delta into the California Aqueduct. This reduction in pumping has limited the ability to move and store water into San Luis Reservoir. This reduced pumping is expected to continue into late spring. The State Water Project anticipates increasing its pumping significantly this summer as soon as the fishery conditions and our State and federal operating permits allow.
“This year highlights the challenges of moving water in wet periods with the current pumping infrastructure in the south Delta. We had both record low pumping for a wet year and high fish salvage at the pumps,” said DWR Director Karla Nemeth. “We need to be moving water when it’s wet so that we can ease conditions for people and fish when dry conditions return. It’s one more reason the Delta Conveyance Project, which would move water when the flows are high in a manner safer for fish, is a necessary climate adaptation project for California.”
Had the Delta Conveyance Project been in place this winter, the State Water Project would have been able to capture an additional 909,000 acre-feet of water since January 1. That’s enough water for 9.5 million people, or 3.1 million households, for a year.
The updated State Water Project allocation forecast announced today anticipates delivery of 40 percent of requested supplies to contractors south of the Delta, which accounts for the majority of contractors; 65 percent of requested supplies to contractors north of the Delta; and 100 percent allocation to Feather River Settlement Contractors.
Allocations are updated monthly as snowpack, rainfall, and runoff information is assessed, with a final allocation typically determined in May or June.
