Sunday, June 15, 2008

River dams won't prevent floods

Gazette-Extra (Janesville, Wisconsin): The Rock River soon will be flowing over land that has been river-free for 100 years or more. What’s going on, and why can’t we do anything about it?

First the background: Heavy rains across the southern half of the state have saturated the Rock River in Wisconsin, covering hundreds of square miles. The river is expected to reach a record high level at Janesville on Wednesday. But all those dams on the river will keep the water in check, right? Nope. How about Lake Koshkonong, won’t it absorb the water? No. Sorry.

Truth is, those dams are not designed to hold vast amounts of water, and Lake Koshkonong already is full, said a Sue Josheff, a DNR civil engineer responsible for the lower Rock River basin. The rule for anything that holds water, be it a wetland or a huge reservoir, is that once it’s full, it’s full, said Kenneth Potter, civil and environmental engineering professor at UW-Madison. It’s a bit more complicated than that, Potter said, but in essence, that’s the situation all along the river….

Fort Atkinson, Wisconsin, during a 2004 flood of the Rock River. Shot by Scott Catron, Wikimedia Commons, under the terms of the GNU Free Documentation license, Version 1.2

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