Following several strong winter storms that brought snowpack and precipitation to above average levels, the California Department of Water Resources (DWR) announced on March 20 an increase to the 2019 State Water Project (SWP) allocation. Most SWP contractors will now receive 70 percent of their requests for the 2019 calendar year, an increase from the 35 percent allocation announced in February.
“Just ten weeks ago it looked like we may have been facing another dry year in California,” said DWR Director Karla Nemeth. “Fortunately, we’ve turned a corner and now it’s shaping up to be a great year for water supply. California’s hydrology varies year to year, which is why all Californians must work together to use water wisely.”
The allocation is assessed monthly and the final allocation is typically determined in May. Last year’s final allocation was 35 percent.
As of March 7, the Northern Sierra 8-station index recorded above average precipitation for water year 2019. While the state has not reached record precipitation like that seen in 2017, February was the third wettest recorded in the Northern Sierra index since 1921 and the sixth wettest in the San Joaquin index since 1913. The statewide Sierra snowpack is 156 percent of average for this date.
Most of the state’s major reservoirs are at or above their historical averages for this time of year. Lake Oroville, the SWP’s largest reservoir, is currently at 76 percent of capacity and 103 percent of average for this time of year. Shasta Lake, the Central Valley Project’s (CVP) largest reservoir, is at 83 percent of capacity and 106 percent of average. San Luis Reservoir, the largest off-stream reservoir in the United States where water is stored for the SWP and CVP, is at 99 percent of capacity and 112 percent of average. In Southern California, SWP’s Castaic Lake is at 81 percent of capacity and 92 percent of average.
Reservoir storage, snowpack, precipitation, and releases to meet water supply and environmental demands are among several factors used in determining allocations.
DWR transports SWP water to 29 SWP contractors which serve more than 27 million Californians and 750,000 acres of farmland. The 2019 allocation of 70 percent amounts to 2,942,158 acre-feet of water.
DWR’s California Data Exchange Center website shows current water conditions at the state’s largest reservoirs and weather stations and measures current rain and snow precipitation.