Thursday, October 03, 2019

Irrigation drying up some waterways in the western U.S.; study warns it will get worse without preventative measures

Farming irrigation is drying up some of the streams and rivers in the western U.S., especially those fed by groundwater bubbling up into natural springs. But farmers have been obliged to dig ever deeper irrigation wells because the region has been seeing less and less rain.

"Farmers have pumped so much water that in some places, the water table has fallen by more than a hundred feet," Dan Charles reports for NPR. "The water is now so deep underground that it can't flow into streams and rivers anymore. Streams dry up, and as a result, fish and plants and birds around those streams also disappear."

It's happening in Kansas, Colorado, and California's Central Valley in the U.S., as well as in India and China. According to a newly published study in Nature, the problem will continue if global warming continues unchecked. A computer simulation of worldwide fresh water sources in such a future, with a warmer planet and less rainfall, means farmers will have to rely even more on groundwater. In the simulation, the flow of freshwater streams and rivers falls dramatically, and about half of them become so dry that the surrounding ecosystems are destroyed, Charles reports.

Inge de Graaf, the lead researcher, puts it bluntly: "The plants and the fish that live in the rivers or the lakes, they will die." She says she doesn't want people to panic, even though the projections are alarming, but says actions like cutting greenhouse gas emissions can help prevent such a scenario from coming to pass, Charles reports.

"In addition, some places, including California and parts of Kansas and Texas, are moving to reduce the amount of groundwater that farmers can extract from the ground," Charles reports.

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