Thursday Feb 28 2013
Snow survey confirms driest January and February on recordBy: RICH PEDRONCELLI and TRACIE CONE, Associated Press
ECHO SUMMIT, Calif. (AP) — It's official, and it's not good news for thirsty Californians: January and February have been the driest on record.
The monthly snow survey, anticipated by farmers and municipalities who depend on snowmelt to supplement water supplies, showed Thursday what everyone has known: despite a few good dumps the state hasn't received the kind of major storms needed to ease water managers' worries.
"It's disappointing, but not really a surprise," said Frank Gehrke, who as head of California's cooperative snow survey program takes manual measurements once a month near Echo Summit in El Dorado County to supplement electronic monitoring.
Gehrke measured 29 inches of snow with a water content of 13.4 inches. The dismal numbers still are twice as much as what was on the ground at this time last year, he said.
There is potentially good news coming by the middle of next week when the National Weather Service forecasts a sizeable storm that could bring more than two-feet of snow across the northern and southern Sierra and up to three-quarters of an inch of rain to the valley.
"The system we're tracking looks fairly potent," said meteorologist Drew Peterson. "It will really help the snowpack and help alleviate the dry start to the calendar year."
Historically about 15 percent of the state's annual precipitation falls in March. Gehrke measured the moisture content of the snowpack at 57 percent of average for the season that ends April 1.
California's Sierra Nevada snowpack provides about one-third of the water used in the state as it melts to fill reservoirs and rivers and replenish aquifers. Water is then delivered from the water-rich north through a system of state and federal canals that have turned arid southern deserts into thriving cities and rich farmland.
Southern California water users have been told to expect 40 percent of their allocation based on current measurements.
Already some of the state's most prolific Central California farmers have been told they're on target to receive just one quarter of their standard allotment, in part because of the lack of precipitation and in part because siphoning water from the Sacramento-San Joaquin Delta has become more challenging to protect a protected smelt.
Thursday's bad news comes as Gov. Jerry Brown's administration pushes a $23-billion plan they say would improve water deliveries to the south by sending it through tunnels under the Delta. Environmentalists argue the only way to save the ecosystem of the Delta, a vast freshwater marshland where rivers from the Cascades, Sierra Nevada and Coast ranges converge and empty into the San Francisco Bay, is to pump less water from it.
The San Luis Reservoir in the Diablos west of Los Banos is the key Delta storage reservoir for Central and Southern California users but is filled to less than 70 percent of what's normal for this date because of pumping restrictions that were triggered in January and February when an increasing number of smelt were killed by the pumps.
Rain storms in November and December created muddy water through the Delta, pushing smelt into the interior, said Maury Roos, chief hydrologist with the state Department of Water Resources.
"There was plenty of water for outflow early in the year, but the pumps had to be throttled back," Roos said.
He estimates about 750,000 million acre feet of water flowed to the ocean instead.
Those early storms left state's northern reservoirs in better shape: Lake Shasta, the largest in the federal Central Valley Water Project system, and Lake Oroville in Butte County, the State Water Project's largest, are at roughly 80 percent capacity.
While the pending storm will improve conditions somewhat, the snow so far has been dry and the water content of the snowpack is just 68 percent of normal, records show.
Much of that snow fell in December, and precipitation in the first two months of the year was barely over two inches, or about 13 percent of what is average.
"It's the third-driest January and February in Sacramento in 150 years, and the driest in California since 1920," when statewide record-keeping began, meteorologist Peterson said.