Big Muddy River The Big Muddy was not covered by the Wisconsin Glacier, about 70,000 to 10,000 years before present. However, during the melting of that glacier, the level of the Mississippi River was much higher. Water backed up into the Big Muddy Basin, forming a lake much like the artificial Rend Lake but covering a larger area. The ancient lake silted in, forming a flat bottom. After the melting of the Wisconsinan glacier, the level of the Mississippi dropped, allowing the lake to drain. A new channel formed within the old lake bed. This channel meandered in the flat bottom of the
Fox River (Illinois River tributary) Fox River (Illinois River tributary) The Fox River is a tributary of the Illinois River, flowing from southeastern Wisconsin to Ottawa, Illinois in the United States. The Wisconsin section was known as the Pishtaka River in the 19th century. There are two other "Fox Rivers" in southern Illinois: the Fox River (Little Wabash tributary) and a smaller "Fox River" that joins the Wabash River near New Harmony, Indiana. The Fox River rises in the Halbach Swamp, southeast of the community of Colgate, Wisconsin and flows past Brookfield, Waukesha, Big Bend, Waterford, Rochester, Burlington, Wheatland, Silver Lake and Wilmot, for a