11 trillion gallons needed to replace California water losses

The bottom of the Almaden Reservoir in San Jose, California on January 28, 2014.
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The bottom of the Almaden Reservoir in San Jose, California on January 28, 2014.

California will need a mind-boggling 11 trillion gallons of water to replace what it has lost so far from its ongoing drought, according to a new report from NASA.

That is about 1.5 times the size of the largest U.S. reservoir.

While the recent storms that battered the coastal regions of the state have brought needed water, they are nowhere near what California will need to fully recover.

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"It takes years to get into a drought of this severity, and it will likely take many more big storms, and years, to crawl out of it," said Jay Famiglietti of NASA's Jet Propulsion Laboratory, in the report.

Famiglietti and his colleagues based their calculation—which NASA says is the first of its kind—on satellite measurements, and presented their findings at the American Geophysical Union meeting in San Francisco on Tuesday.

Water levels in the Sacramento and San Joaquin rivers have fallen by roughly 4 trillion gallons per year since 2011 according to the data.

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The majority of the loss—about two-thirds of it—came from groundwater supplies in California's Central Valley, known partly for its crucial role in the state's multibillion-dollar agricultural sector.

Not much snow has fallen either. Snowpack in California's Sierra Nevada range in early 2014 was half of what scientists had estimated it would be, according to data released by NASA's Airborne Snow Observatory. This past year's snowpack numbers are among the worst since the late 1970s, when the state's population was half of what it is today.