Decades of overpumping groundwater have irreversibly altered layers of clay beneath California's Central Valley, permanently reducing the aquifer's ability to store water, finds a new satellite remote sensing study by scientists at Stanford University, Stanford, California; and NASA's Jet Propulsion Laboratory in Pasadena, California.
Decades of overpumping groundwater have irreversibly altered layers of clay beneath California's Central Valley, permanently reducing the aquifer's ability to store water, finds a new satellite remote sensing study by scientists at Stanford University, Stanford, California; and NASA's Jet Propulsion Laboratory in Pasadena, California.
The study, published online in the journal Water Resources Research, reveals that overpumping caused land in the state's San Joaquin Valley to sink almost 3 feet (85 centimeters) during a recent drought from 2007 to 2010. As a result, the aquifer permanently lost between 336,000 and 606,000 acre-feet of natural water storage capacity. An acre-foot is equal to 326,000 gallons. In comparison, the Hetch Hetchy Reservoir that stores the primary water supply for the San Francisco Bay area has a capacity of about 360,000 acre-feet.
The San Joaquin Valley is one of the largest U.S. agricultural hubs, producing an estimated $17 billion of crops a year. The new findings come just as the state is experiencing its wettest season in years following an extended, record-setting drought.
"California is getting all of this rain, but in the Central Valley, there has been a loss of space to store it," said study coauthor Rosemary Knight, George L. Harrington professor at Stanford's School of Earth, Energy & Environmental Sciences.
Read more at NASA's Jet Propulsion Laboratory
Photo courtesy of USDA Natural Resources Conservation Service via Wikimedia Commons
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