Heatwave turns Americas waterways into rivers of death, Falling water levels are killing fish and harming exports

Heatwave turns Americas waterways into rivers of death, Falling water levels are killing fish and harming exports by David Usborne, August 5, 2012, The Independent
Army Corps of Engineers is dredging around the clock to try to keep barges from grounding as water levels dive. For scientists the impact of a long, hot summer that has plunged more than two-thirds of the country into drought conditions – sometimes extreme – has been particularly striking in the Great Lakes. According to the Great Lakes Environmental Research Laboratory, all are experiencing unusual spikes in water temperature this year. It is especially the case for Lake Superior, the northernmost, the deepest, and therefore the coolest. “It’s pretty safe to say that what we’re seeing here is the warmest that we’ve seen in Lake Superior in a century,” said Jay Austin, a professor at the University of Minnesota at Duluth. The average temperature recorded for the lake last week was 68F (20C). That compares with 56F (13C) at this time last year. … But the warming of the rivers, in particular, is taking a harsh toll on fish, which are dying in increasingly large numbers. … In some instances, fish are simply left high and dry as rivers dry up entirely. It is the case of the normally rushing River Platte which has simply petered out over a 100-mile stretch in Nebraska, large parts of which are now federal disaster areas contending with so-called “exceptional drought” conditions. “The river was full of fish, and to see them all die is a travesty.”