Sunday, October 21, 2007

Rivers, reservoirs drying out in the American West

Water managers are scrambling for solutions as water levels drop in the arid West. The combination of cyclical drought and, probably, global warming-induced drought, are creating a dire situation:

Last May, for instance, Steven Chu, a Nobel laureate and the director of the Lawrence Berkeley National Laboratory, one of the United States government’s pre-eminent research facilities, remarked that diminished supplies of fresh water might prove a far more serious problem than slowly rising seas. When I met with Chu last summer in Berkeley, the snowpack in the Sierra Nevada, which provides most of the water for Northern California, was at its lowest level in 20 years. Chu noted that even the most optimistic climate models for the second half of this century suggest that 30 to 70 percent of the snowpack will disappear. “There’s a two-thirds chance there will be a disaster,” Chu said, “and that’s in the best scenario.”

In the Southwest this past summer, the outlook was equally sobering. A catastrophic reduction in the flow of the Colorado River — which mostly consists of snowmelt from the Rocky Mountains — has always served as a kind of thought experiment for water engineers, a risk situation from the outer edge of their practical imaginations. Some 30 million people depend on that water. A greatly reduced river would wreak chaos in seven states: Colorado, Utah, Wyoming, New Mexico, Arizona, Nevada and California. An almost unfathomable legal morass might well result, with farmers suing the federal government; cities suing cities; states suing states; Indian nations suing state officials; and foreign nations (by treaty, Mexico has a small claim on the river) bringing international law to bear on the United States government. In addition, a lesser Colorado River would almost certainly lead to a considerable amount of economic havoc, as the future water supplies for the West’s industries, agriculture and growing municipalities are threatened. As one prominent Western water official described the possible future to me, if some of the Southwest’s largest reservoirs empty out, the region would experience an apocalypse, “an Armageddon.”
Read the whole thing.

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