San Francisco Chronicle
Winter storms fill largest state reservoirs
California’s plentiful rain this winter has been a boon to reservoirs parched from years of drought, data shows.
Each of the state’s eight largest reservoirs — those with over 1 million acre-feet in capacity — has seen its water level steadily rise since December. While three of these major reservoirs, Oroville, Don Pedro and McClure, have surpassed their historical average water storage level for this time of year, the others have not.
Trinity Lake, the third-largest reservoir in the state, remains at 48% of historical average, according to data as of March 1 from the Department of Water Resources. That reservoir diverts water to valley farmers and for hydropower generation,
It’s a very different picture from a year ago, when none of the eight largest reservoirs were at more than 80% of their historic average water storage, and all had lower levels of water than they do now.
Big reservoirs near the Bay Area are also faring relatively well. Lake Sonoma near Cloverdale has surpassed its historic average for this time of year, while last year it was only at 62%. Lake Berryessa, one of the eight largest reservoirs in the state, is also up — it’s at 83% of its historic average, compared with 78% at this time last year.
The San Luis Reservoir near Highway 152 in Merced County, another of the state’s largest, is now at 95% of its historic average, compared with just 54% last year. The nearby Los Banos Reservoir is now up to 120% of its historic average, compared with 99% last year.
Statewide, reservoirs overall are at 96% of average levels for this time of year — up from 68% in early December and up from 84% in early January, a sign of just how much water the storms during the last two months have brought.
California officials generally prevent reservoirs from becoming full at this time of year, lest more storms bring intense runoff that the reservoirs can store to prevent flooding.
The high reservoir levels are another sign that the state’s drought conditions are improving. In its latest drought monitor update released Thursday, the federal government determined that just over half the state is now out of drought categorization. Three months ago, the whole state was in a drought.
While about 17% of the state is not in any drought at all, much of the state is still labeled “abnormally dry,” which is one category away from a formal drought designation. But that’s far better than a year ago, when about 87% of the state was in the “severe drought” category, the third worst categorization, or “extreme drought.” No areas a year ago were in the worst category, “exceptional drought.”
Gov. Gavin Newsom declared a statewide drought emergency in 2021 following two consecutive years of critical drought. The state entered the new crisis not long after it emerged from the last one: Then-Gov. Jerry Brown issued the last statewide drought declaration, in 2014, and kept it in place for three years.