Water loss of 63 trillion gallons causing western U.S. ground to rise
The growing problem of water loss may also be responsible for lifting ground levels of the western U.S. The discovery was made by researchers at the Scripps Institution of Oceanography in University of California, San Diego and their findings were published in the online journal Science last Aug. 21.
The researchers investigated ground position data through GPS stations installed all over the western U.S. and discovered that water shortage is bringing about an “uplift effect” of up to 15 millimeters or over half an inch in the mountains of California and four millimeters or 0.15 of an inch on the average across the western section.
“These results quantify the amount of water mass lost in the past few years,” Dan Cayan, research meteorologist at Scripps and USGS, says in a statement. “It also represents a powerful new way to track water resources over a very large landscape. We can home in on the Sierra Nevada mountains and critical California snowpack. 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.”
The Scripps researchers estimated the deficit of water at almost 240 gigatons or 63 trillion water gallons, which are equivalent to four-inch water layer spread all over the whole of western U.S.
An assistant research geophysicist at Scripps, Adrian Borsa kept noticing that all the GPS stations have moved upwards in the current years, from 2003 to 2014, corresponding with the timing of the drought currently being experienced. This same pattern was observed while he was going through several sets of ground positions data from the GPS stations within the Plate Boundary Observatory and networks of the National Science Foundation.
Meanwhile, Scripps geophysics professor Duncan Agnew says the data from GPS can be merely explained by the swift uplift of tectonic plate on which the West sits. Agnew, who is specializing in studying earthquakes and its impact on the shaping of the crust of the Earth, warns that such uplift has nearly no effect on the San Andreas fault and doesn’t expand the risk of earthquakes.
According to independent organization Climate Central, U.S experienced in 2012 one of the worst droughts ever recorded in its history. It was also referred to as the most widespread drought since the year 1956 and obtained comparisons as well to the Dust Bowl era of the 1930s.
The eastern part of the U.S may have loosened up its conditions, but extreme drought remains in the larger area of the country, west of Mississippi River.
Based on the latest assessment of the organization on Aug. 12, the severe drought has brought about damages to commerce, cattle and crops worth at least $30 billion all over U.S.
The Scripps study, Ongoing drought-induced uplift in the western United States, was supported by the U.S. Geological Survey.