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
Muddy River (Nevada) National Wildlife Refuge Complex. In another effort to help protect and preserve the fragile habitats in the Muddy Springs area, the Southern Nevada Water Authority (SNWA) and various environmental associations have organized an effort to conserve these species. The area was part of the Native American Paiute peoples homeland for centuries, with the Mojave to the south. "Moapa" is a Southern Paiute language word meaning "muddy"; although "Moapa River" was formerly the official name, local usage tended to translate the name, and it was made official in 1960. The Old Spanish Trail originally followed the Virgin River all the way