NASA Satellites Reveal the True Extent of California's Severe Drought

How severe is California's drought? That's a good question. Now, scientists have examined exactly how much water would be needed to recover from the drought, and the results are less than optimistic.

A drought has continued to plague California for the past three years. That's why researchers decided to take a closer look at the state. The researchers used data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites in order to find out the volume of water required to end an episode of drought.

"Spaceborne and airborne measurements of Earth's changing shape, surface height and gravity field now allow us to measure and analyze key features of droughts better than ever before, including determining precisely when they begin and end and what their magnitude is at any moment in time," said Jay Famiglietti, one of the researchers, in a news release. "That's an incredible advance and something that would be impossible using only ground-based observations."

The researchers found that since 2011, the Sacramento and San Joaquin river basins in California have decreased in volume by four trillion gallons of water each year. That's more water than all of California's residents use for domestic and municipal purposes each year. About two-thirds of this loss is due to depletion of groundwater beneath California's Central Valley.

That's not all, either. The scientists found that snowpack in California's Sierra Nevada range was only half of previous estimates. In fact, the 2014 snowpack was one of the three lowest on record and the worst since 1977, when California's population was half of what it is now.

Perhaps the most unfortunate finding was that the drought will continue. While recent California storms have been helpful in replenishing water resources, they aren't nearly enough to end the multi-year drought. In fact, scientists estimate it will take about 11 trillion gallons of water to recover.

The findings may help water managers better allocate resources. In addition, it gives scientists a clearer view of the ongoing drought.

For more information on GRACE, visit NASA's website.

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