The biggest storm of the rain season is fostering optimism among state officials, who increased 2015 water allocations this week in response to improving precipitation forecasts.
On Monday, the Department of Water Resources announced that in 2015 water agencies will receive an initial allocation of 10% of the amount of water they requested from the State Water Project – double the 5% allocation customers received in 2014.
California's recent storms have increased the water level of Lake Oroville – the "keystone" reservoir of the State Water Project – officials said in a news release. The project is a series of reservoirs, canals and aqueducts that move water from Northern California to the south.
Still, state water experts said it would take about 1.5 times more rainfall than average for California to recover from the current drought. According to the water department, that would mean a total 75 inches of rain from Oct. 1, 2014 through Sept. 30, 2015 recorded at eight stations in the northern Sierras.
If dry conditions return, officials cautioned that they could "reallocate State Water Project supplies to meet critical human health and safety needs."
"Storms in the extended forecast give us hope that we will return this winter to normal or above-normal precipitation levels after three years of drought," DWR Director Mark Cowin said. "But we must be cautious and preserve adequate storage in reservoirs should conditions turn dry again."
Almost all areas served by the State Water Project also receive water from other sources, such as streams, groundwater and local reservoirs. But the 5% allocation in 2014 was the lowest amount at the end of a calendar year in the project's 52-year history, officials said. For comparison, the final allocation for the 2013 calendar year was 35%.
Other parts of the state's water picture were less rosy. The DWP released an updated report on groundwater basins Tuesday, which showed that in most areas of the state the basins are at historically low levels.
Also Tuesday, officials at the State Water Resources Control Board issued a monthly report on water conservation, announcing that Californians reduced use by 6.7% in October compared to October 2013. Californians cut 11.6% in August and 10.3% in September.
Water board officials said that Southern California was a driver of state water use. While most of the state's hydrologic regions continued to conserve at consistent rates, the South Coast Hydrologic Region, which includes Los Angeles, reduced its water use only 1.4% in October. During summer months, the region had cut use by as much as 7.8%, helping push statewide water conservation to its highest levels this year.
Despite the recent Southland storms, "it's not time to relax," said Eric Oppenheimer, director of the State Water Board's Office of Research. "We would have definitely liked to have seen better than the 6.7%."