Researchers say it could take four years for California to recover from historic drought, even if the next several winters bring above-normal snowfall to the Sierra Nevada.
Professor Steve Margulis at the University of California, Los Angeles, published research Tuesday showing that the last four years of drought have left a deficit to the state's water supply.
Snow typically falls each winter in the Sierra and melts during the warm months. It provides water to millions of residents and vast farmland in the nation's leading agricultural state.
Margulis says that even the El Nino storms that delivered a near-normal winter weren't enough for a fully recovery; the low snowpack puts pressure on groundwater and draws down reservoirs.
Margulis says he hopes this research will help state leaders chart water policy.