![]() ![]() Single-channel seismic reflection data were collected to determinethickness and distribution of rock and sediments. Together, these data provide the basis for preparing lake-bottom maps of physiography and sediment distribution. Map of southern Lake Michigan showing areas surveyed using sidescan sonar imagery and seismic reflection track lines. USGS investigations involved basic geophysical data collection and ground-truth mapping. ![]() The study is a cooperative effort involving research staff from the Illinois State Geological Survey, the Indiana Geological Survey, Indiana University, Purdue University, Northeast Illinois University, the University of Illinois at Chicago, Oregon State University, the University of Washington, the University of Rhode Island, and the Woods Hole Oceanographic Institution. The USGS initiated a 5-year study to document the timing and magnitude of prehistoric lake-level fluctuations, and to assess some of the important geologic processes responsible for severe erosion of the Illinois-Indiana shoreline. The culmination of thehigh-water levels in 1985-87 caused extensive damage. Since the turn of the century, water levels of Lake Michigan have increasedin a series of peaks, each higher than the last. Geological Survey (USGS) scientists initiated a coastal study of Southern Lake Michigan in response to disastrous flooding in Chicago. Geological SurveyĮrosion and flooding of Lake Michigan's coastline have resulted in extensive damage to domestic, recreational, and industrial facilities.Īs the result of fluctuating water levels in the Great Lakes, hundreds ofmillions of dollars have been lost by the 40 million people and by the manyindustries vital to our economy that are located in the Great Lakes Basin.During each episode of high lake levels, rates of bluff erosion increase,beachfront property is lost, and structures and beaches are submerged.During each intervening episode of low lake levels, navigation channels andharbors require extensive dredging of sediments that commonly are polluted.Also, hydroelectric output decreases, the load on freshwater pumpingfacilities increases, and sewage disposal becomes a more complex issue. David Folger, Steve Colman, and Peter Barnes, U.S. About83 percent of the shoreline is privately-owned with property values ashigh as $10,000 per linear foot of lakefront." About 15 percentof the United States' and 50 percent of Canada's population live alongor near the 9,000-kilometer-long coastline of the Great Lakes. It is important to understand how these processes shape our daily lives. "Geological Survey studies the geologic processes at work in the Great Lakes region because they have direct bearing on the use, management, development, and preservation of the shoreline. Coastal Erosion of Southern Lake Michigan - USGS Fact SheetĬoastal and Marine Geology Program > Coastal Erosion of Southern Lake Michigan Coastal Erosion of Southern Lake Michigan USGS Fact Sheet
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