Drenching rain belts area anew, for better or worse
‘Drought is over’: At least in far northern part of state
The storms barreling into California aren’t only flooding towns, ripping trees from the earth and igniting roadway chaos.
They’ve had the extraordinary effect of filling reservoirs that haven’t breached their brims in years and, for much of the north state, intensifying a rainy season that is finally, mercifully, driving an end to the historic drought.
“In the very northern part of California, yes, the drought is over,” said Marty Ralph, director of the Center for Western Weather and Water Extremes
at UC San Diego’s Scripps Institution of Oceanography. “In the south, not so much.”
This weekend, so much water fell from the sky that at one point nearly 63 million gallons of water per minute poured into the Folsom Reservoir near Sacramento, leaving dam operators at the long-dry basin opening the floodgates in an exercise that has occurred just a few times in the past five years.
The story was similar across the state. California’s 154 major reservoirs on Tuesday held what they typically do after January, normally the wettest month.
At Don Pedro Reservoir outside Yosemite, which San Francisco shares with irrigation districts in Modesto and Turlock and serves as the largest storage site for the city and its southern suburbs, the Bay Area holdings reached capacity.
“This is a big deal,” said Charles Sheehan, a spokesman for the San Francisco Public Utilities Commission, noting that the agency now has at least five years’ worth of supplies for its 2.6 million customers. “We were very nervous. It was three or four dry years in a row, and our water bank was getting lower and lower.”
The greatly improved reserves are the result of an atmospheric river — essentially massive channels of storm clouds that provide up to 50 percent of the state’s water — that struck California in the New Year after a wet fall.
In just a week, the Big Sur coast got nearly 15 inches of rain, about a third of what it normally sees in a year, while parts of the Sierra got close to a foot, according to the National Weather Service.
“Atmospheric rivers occur every winter, it’s just a matter of where they occur,” said Ralph. “The last two years they’ve been missing in California. In the past three months we’ve had a large number.”
On Tuesday, the muchwatched Northern Sierra Eight-Station Precipitation Index, which measures rainfall between the Oregon border and Lake Tahoe, approached 42 inches, the most ever recorded at this point in the Octoberthrough-September water year.
Meanwhile, snowpack, a barometer of the runoff that will fill reservoirs in spring and summer, was at 135 percent of normal for the date.
While the state’s Southland has not fared as well, northerly precipitation remains the most vital in the drought picture because it feeds the big reservoirs that supply water across the state.
California has been struggling with dry conditions since 2011. Last winter wasn’t as bad, bringing above-average snow and rain to the north amid an El Niño weather pattern, but water supplies have remained short.
While this year’s wet weather has been a boon for reservoirs, five years of drought forced many communities to rely heavily on aquifers, and underground supplies in many places are now depleted.
“We have not busted our groundwater drought,” said Jeffrey Mount, a senior fellow at the Public Policy Institute of California’s Water Policy Center.
Since 30 percent of the state’s water supply comes from the ground, and as much as 60 percent when surface supplies dry up, Mount said California’s aquifers need more time — years, if not decades — to recover.
Other problems wrought by the drought show little sign of immediate improvement.
A massive die-off of dry, beetle-infested trees continues to plague the Sierra. Fish that suffered from years of overdrawn rivers, some on the brink of extinction, remain without assurances of winning back habitat. Dried-up soils and farmland could also go a long time without recovery.
There’s fear, too, that the rainy season, which generally runs from late October through March, could still take a turn for the worse. The water year has started with a blockbuster December before, only to stall out the rest of winter.
The state’s official drought declaration, issued by Gov. Jerry Brown in January 2014, has yet to be lifted.
The unprecedented rationing that was mandated for cities and towns, and deep water cuts for farmers, have been eased. But many of the regulations governing water deliveries remain.
“There are just some communities that are still struggling,” said Mike Anderson, the state climatologist with the Department of Water Resources.
Santa Barbara, for example, watched one of its main reservoirs, Lake Cuchuma, miss out on most of the recent storms, and the lake remains less than a quarter full.
Other reservoirs, mostly in Southern California, are also yet to near capacity after years of withdrawals outpacing inflows.
“Everybody has their own portfolio of supply options and their own portfolio of demands, and it’s really a matter of figuring out how to balance them in each of these areas,” Anderson said. “We’re certainly in a better place than we’ve been.”