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This trio of images depicts satellite observations of declining water storage in California as seen by NASA's Gravity Recovery and Climate Experiment satellites in June 2002 (left), June 2008 (center) and June 2014 (right). Colors progressing from green to orange to red represent greater accumulated water loss between April 2002 and June 2014.
California's Sacramento and San Joaquin River basins, including the Central Valley, have suffered the greatest losses, in part due to increased groundwater pumping to support agricultural production. Between 2011 and 2014, the combined river basins have lost 4 trillion gallons (15 cubic kilometers, or 12 million acre-feet) of water each year, an amount far greater than California's 38 million residents use in cities and homes annually.
GRACE is a collaborative endeavor involving the Center for Space Research at the University of Texas, Austin; NASA's Jet Propulsion Laboratory, Pasadena, Calif.; the German Space Agency and Germany's National Research Center for Geosciences, Potsdam.