Tapped OutPosted in: Global Ag By Tracy Tjaden October 16 2014
The severe drought gripping the western United States in recent years is changing the landscape well beyond localized effects of water restrictions, browning lawns or even parched cropland.
Scientists at Scripps Institution of Oceanography at UC San Diego have just discovered that the growing, broad-scale loss of water is causing the entire western U.S. to “rise up like an uncoiled spring,” said a Scripps release.
In a study released in late August, Scripps researchers Adrian Borsa, Duncan Agnew, and Dan Cayan found that the water shortage is causing an “uplift” effect up to 15 millimetres or more than half an inch in California’s mountains and on average four millimeters (0.15 of an inch) across the west.
By investigating ground positioning data from GPS stations throughout the west, they estimated the water deficit at nearly 63 trillion gallons of water, equivalent to a four-inch layer of water spread out over the entire western U.S.
Results of the study, which was supported by the U.S. Geological Survey (USGS), appeared online edition of the journal Science.
Agnew, a Scripps Oceanography geophysics professor who specializes in studying earthquakes and their impact on shaping the earth’s crust, says the GPS data can only be explained by rapid uplift of the tectonic plate upon which the western U.S. rests.
For Cayan, a research meteorologist with Scripps and USGS, the results paint a new picture of the dire hydrological state of the west.
“These results quantify the amount of water mass lost in the past few years,” said Cayan in the release. “It also represents a powerful new way to track water resources over a very large landscape. These results demonstrate that this technique can be used to study changes in fresh water stocks in other regions around the world, if they have a network of GPS sensors.”
An estimated 82 percent of California is experiencing extreme drought, according to the U.S. Drought Monitor. Agriculture consumes about four-fifths of the water that isn’t set aside for environmental preservation.
Farmers in the western U.S. have been adapting to the severe crops by shifting acres out of commodity crops into more high-value crops, or taking land out of production altogether.
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