Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

California’s troubled waters

16.12.2009
Satellite-based findings by UCI, NASA reveal significant groundwater loss in Central Valley

New space observations reveal that since October 2003, the aquifers for California’s primary agricultural region – the Central Valley – and its major mountain water source – the Sierra Nevada – have lost nearly enough water combined to fill Lake Mead, America’s largest reservoir. The findings, based on satellite data, reflect California’s extended drought and increased pumping of groundwater for human uses such as irrigation.

At the American Geophysical Union meeting this week in San Francisco, UC Irvine and NASA scientists detailed the state’s groundwater changes and outlined research on other global aquifers conducted via twin satellites called the Gravity Recovery and Climate Experiment. GRACE monitors tiny month-to-month differences in Earth’s gravity field primarily caused by the movement of water in the planet’s land, ocean, ice and atmosphere. Its ability to “weigh” changes in water content provides new insights into how climate change is affecting Earth’s water cycle.

Combined, California’s Sacramento and San Joaquin drainage basins have shed more than 30 cubic kilometers of water since late 2003, said Jay Famiglietti, UCI Earth system science professor and director of the UC Center for Hydrologic Modeling. A cubic kilometer is about 264.2 billion gallons, enough to fill 400,000 Olympic-size pools. The bulk of the loss occurred in the state’s agricultural Central Valley. The Central Valley depends on irrigation from both groundwater wells and diverted surface water.

“GRACE data reveal groundwater in these basins is being pumped for irrigation at rates that are not sustainable if current trends continue,” Famiglietti said. “This is leading to declining water tables, water shortages, decreasing crop sizes and continued land subsidence. The findings have major implications for the U.S. economy, as California’s Central Valley is home to one-sixth of all U.S. irrigated land and the state leads the nation in agricultural production and exports.”

“By providing data on large-scale groundwater depletion rates, GRACE can help California water managers make informed decisions about allocating water resources,” said project scientist Michael Watkins of NASA’s Jet Propulsion Laboratory.

Preliminary studies show most of the water loss is coming from the more southerly located San Joaquin basin, which gets less precipitation than the Sacramento River basin farther north. Initial results indicate the Sacramento River basin is losing about 2 cubic kilometers of water a year. Surface water losses account for half of this, while groundwater losses in the northern Central Valley add another 0.6 cubic kilometers annually. The San Joaquin basin is losing 3.5 cubic kilometers a year. More than 75 percent of this is due to groundwater pumping in the southern Central Valley, primarily to irrigate crops.

Famiglietti said recent California legislation decreasing the allocation of surface water to the San Joaquin basin is likely to further increase the region’s reliance on groundwater for irrigation. “This suggests the decreasing groundwater storage trends seen by GRACE will continue for the foreseeable future,” he said.

The California results come just months after Matt Rodell of NASA’s Goddard Space Flight Center, Isabella Velicogna of UCI, and Famiglietti found groundwater levels in northwest India declining by 17.7 cubic kilometers per year between October 2002 and August 2008, a loss attributed almost entirely to pumping and consumption of groundwater by humans.

“California and India are just two of many regions around the world where GRACE data are being used to study droughts, which can have devastating impacts on societies and cost the U.S. economy $6 billion to $8 billion annually,” said Rodell, who was Famiglietti’s doctoral student at the University of Texas at Austin.

Other regions under study include the southeastern U.S., where GRACE clearly captured the evolution of an extended drought that ended this spring; Australia; and the Middle East-North Africa region. There, Rodell is leading an effort to assess regional water resources by using GRACE and other data to systematically map water and weather-related variables. He said GRACE may also help predict droughts, since it can identify pre-existing conditions favorable to the start of a drought, such as a deficit of water deep below ground.

GRACE is a NASA/German Aerospace Center (DLR) partnership. The University of Texas Center for Space Research has overall mission responsibility. JPL developed the satellites; DLR provided the launch; and GeoForschungsZentrum Potsdam, Germany, operates the mission. For more on GRACE, see http://www.csr.utexas.edu/grace/ and http://grace.jpl.nasa.gov/.

About the University of California, Irvine: Founded in 1965, UCI is a top-ranked university dedicated to research, scholarship and community service. Led by Chancellor Michael Drake since 2005, UCI is among the fastest-growing University of California campuses, with more than 27,000 undergraduate and graduate students, 1,100 faculty and 9,200 staff. The top employer in dynamic Orange County, UCI contributes an annual economic impact of $4.2 billion.

News Radio: UCI maintains on campus an ISDN line for conducting interviews with its faculty and experts. Use of this line is available for a fee to radio news programs/stations that wish to interview UCI faculty and experts. Use of the ISDN line is subject to availability and approval by the university.

Jennifer Fitzenberger | EurekAlert!
Further information:
http://www.today.uci.edu

More articles from Earth Sciences:

nachricht Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute

nachricht How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>