Big Muddy River Wisconsinan-era lake. This is why the Big Muddy tends to be so muddy. The Big Muddy joins the Mississippi River in Jackson County near the La Rue-Pine Hills Ecological Area and less than south of Grand Tower Island. The Pine Hills are bluffs overlooking the Big Muddy as it flows through La Rue swamp. During the melting of the Wisconsinan glacier, the Mississippi River flood plain was filled with rushing meltwater in summer. During the winter the flow of meltwater was cut off, and the floodplain was a wide stretch of exposed mud. Winter winds created dust storms that covered
Muddy River (Washington) rapidly, passing under Forest Road 25 and then receiving Clear Creek from the left about from the mouth. At the road crossing, Muddy Creek Picnic Site is on the left. Below the confluence with Clear Creek, the river meanders through Cedar Flats, leaves the national forest slightly more than a mile from the mouth, and passes a United States Geological Survey (USGS) stream gauge, on the left from the mouth. Muddy River enters the Lewis River about from the larger stream's mouth on the Columbia River. The USGS monitors the flow of Muddy River at a station upstream of the