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The U.S.-Canada Great Lakes Water Quality Agreement [exit DNR] defines an Area of Concern (AOC) as "a geographic area designated by the Parties where significant impairment of beneficial uses has occurred as a result of human activities at the local level." An AOC is a location that has experienced environmental degradation. EPA and other federal and state agencies are working to restore the 25 remaining U.S. AOCs in the Great Lakes basin, five of which are in Wisconsin and are listed below.
Name Description Lake
LOWER GREEN BAY/FOX RIVER AOC The Lower Green Bay and Fox River AOC is part of the Fox Wolf Watershed. The AOC spans the last seven miles of the Lower Fox River (downstream of the De Pere Dam to the mouth) and includes 22 square miles of southern Green Bay. Michigan
LOWER MENOMINEE RIVER AOC The Lower Menominee River forms the boundary between the northeast corner of Wisconsin and the southern tip of Michigan’s upper peninsula, with headwaters originating in both states. The river’s main stem flows from the city of Menominee, Mich., and Marinette, Wis., and empties into Green Bay. All Beneficial Use Impairments have been removed and the AOC is now delisted. Michigan
MILWAUKEE ESTUARY AOC The Milwaukee Estuary AOC includes Cedar Creek, the Milwaukee, Little Menomonee, Menomonee and Kinnickinnic Rivers, and the inner and outer Harbor and nearshore waters of Lake Michigan. Michigan
SHEBOYGAN RIVER AOC The Sheboygan River AOC encompasses 14 miles of the lower Sheboygan River downstream from the Sheboygan Falls Dam and includes the entire harbor and nearshore water of Lake Michigan. Michigan
ST. LOUIS RIVER AOC Draining 3,634 square miles of watershed and encompassing a 1,020 square-mile area, the St. Louis River is the second largest U.S.-based AOC. It crosses state boundaries, including both the states of Minnesota and Wisconsin. Superior
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