[env-trinity] Christian Science Monitor 1 4 10

Byron Leydecker bwl3 at comcast.net
Fri Jan 15 10:54:16 PST 2010



California's groundwater shrinking because of agricultural use

In California, NASA satellites show that groundwater has diminished because
of aggressive agricultural irrigation.

By Garance <http://www.csmonitor.com/About/Contact-Us-Feedback>  Burke
Associated Press Writer
Christian Science Monitor
January 4, 2010 

 A crew digs a well in an alfalfa field in Dos Palos, Calif. Recent
satellite measurements show that the aquifer lying below the San Joaquin
Valley has dropped, as farmers and developers have drilled deeper wells to
tap underground supplies amid the three-year drought. AP Photo/Russel A.


FRESNO, Calif. -- New data from satellites show the vast underground pools
feeding faucets and irrigation hoses across California are running low, a
worrisome trend federal scientists largely attribute to aggressive
agricultural pumping.

The measurements show the amount of water lost in the two main Central
Valley river basins within the past six years could almost fill the nation's
largest reservoir, Lake Mead in Nevada.

"All that water has been sucked from these river basins. It's gone. It's
left the building," says Jay Famiglietti, an earth science professor at the
University of California, Irvine, who led the research collaboration. "The
data is telling us that this rate of pumping is not sustainable."

Hundreds of farmers have been drilling wells to irrigate their crops, as
three years of drought and environmental restrictions on water supplies have
withered crops, jobs and profits throughout the San Joaquin Valley, where
roughly half of the nation's fruits, nuts, and vegetables are grown.

Developers and cities dependent on the tight supplies also have joined the
well-drilling frenzy as the crisis has deepened.

NASA scientists and researchers from UC Irvine presented their findings at a
recent conference, showcasing data from twin satellites that pick up changes
in the aquifers coursing underneath the state.

The NASA mission represents the first attempt to use space-based technology
to measure how much groundwater has been lost in recent years in California
and elsewhere in the world.

>From October 2003 through March of this year, Mr. Famiglietti and his team
tracked how Earth's gravitational pull on the satellites changed as the
amount of water stored in the Sacramento and San Joaquin river basins dried

As river water, snowmelt, soil moisture and aquifer levels declined, the
satellites sensed less of a pull to the planet, which allowed scientists to
extrapolate over time how much water had disappeared.

More than three-quarters of the loss was due to groundwater pumping in the
southern Central Valley, primarily to irrigate crops, researchers found.

If drilling keeps on at the same clip, scientists warned, more wells could
start running dry.

"We've known about the conditions in California for a while since it's one
of the most pumped aquifers in the United States," says Michael Watkins,
NASA's Pasadena-based project scientist for the Gravity Recovery and Climate
Experiment mission.

"Hydrologists were just surprised to see that the deep water conditions had
dropped so much, since it was more than we had expected," he says.



Byron Leydecker, JcT

Chair, Friends of Trinity River

PO Box 2327

Mill Valley, CA 94942-2327

415 383 4810 land/fax (call first to fax)

415 519 4810 mobile

 <mailto:bwl3 at comcast.net> bwl3 at comcast.net

 <mailto:bleydecker at stanfordalumni.org> bleydecker at stanfordalumni.org

 <http://fotr.org/> http://www.fotr.org 




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