Tuesday, September 30, 2008

Hurricane Ike's lingering impact on the Great Lakes

US Geological Survey: Although Hurricane Ike is long gone, its impact lingers more than a thousand miles from where it made landfall. Runoff from tributaries dumped massive amounts of sediment into Lake Michigan, contaminating the water, compromising near-shore navigation and raising E coli bacteria to levels unsafe for swimming. According to Richard Whitman, a U.S. Geological Survey (USGS) expert on beach health, "The local effects that Ike had on Lake Michigan's Indiana shoreline, water depth, and water quality have been profound."

While assessing Ike's impact on the lake, Whitman noted that "The velocity and height of a tributary emptying into Lake Michigan at Portage, Indiana went off the chart. We measured a tremendous amount of sediment accumulation Near Ogden Dunes." USGS scientists use high tech, state-of-the-art equipment in the lake to measure runoff, the lake's currents, and sediment input during storms. These data are used to forecast whether a beach is unsafe for swimmers. Beaches are subject to high bacteria levels following storms….

E. coli, image from US Food and Drug Administration

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