The situation is worse under the snow-starved
mountains of California, where the Earth rose three-fifths of an inch.
Groundwater is very heavy, and its weight depresses the Earth’s upper
crust. Remove the weight, and the crust springs upward.
The study, published online Thursday by the journal
Science, shows how a lack of rain and snow cuts water levels first in
the U.S. Southwest and Central and Southern California before spreading
into Oregon and Washington state. Water naturally evaporates, is
absorbed by plants and is pumped by humans, so levels go down if the
water is not replenished.
“The thing that is exceptional about this drought is
that it really covers the entire region” of the Western U.S., said
Scripps assistant researcher Adrian Borsa, the study’s lead author.
The lost water is equal to a 4-inch layer of water across the United States west of the Rocky Mountains, according to the study.
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