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
Illinois River (Colorado) Illinois River (Colorado) Illinois River is a tributary of the Michigan River, approximately long, in Jackson County in north central Colorado. It drains part of the North Park basin south of Walden. The Illinois River starts in the Never Summer Mountains near the continental divide, just south of Farview Mountain. It descends northward through a winding gorge, emerging into North Park at approximately above sea level. It flows northward through the valley as a winding stream, past Rand. It passes under State Highway 14 just southeast of Walden and joins the Michigan from the north just north of Walden. A