SAN FRANCISCO, Dec. 15 (UPI) -- The U.S. space agency says new satellite data show a major loss of water from aquifers in California's primary agricultural region.
NASA officials said the data reveal that since October 2003, California's Central Valley aquifers -- and the state's major mountain water source, the Sierra Nevadas -- have lost nearly enough water combined to fill Lake Mead, the nation's largest reservoir.
University of California-Irving and NASA scientists say the findings are based on data from the NASA-German Aerospace Center Gravity Recovery and Climate Experiment satellites known as Grace. The twin satellites monitor tiny month-to-month changes in the Earth's gravity field that are primarily caused by the movement of water in land, ocean, ice and atmosphere reservoirs.
Professor Jay Famiglietti said California's Sacramento and San Joaquin drainage basins have shed more than 7.9 trillion gallons since late 2003.
"Grace data reveal groundwater in these basins is being pumped for irrigation at rates that are not sustainable if current trends continue," Famiglietti said. "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."
The research is being presented in San Francisco this week during a meeting of the American Geophysical Union.
