Snow
survey confirms driest Jan., Feb. on record in California
It's
official, and it's not good news for thirsty Californians: January
and February have been the driest on record.
2
February, 2013
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.
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.
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