Gravel chub silt and debris. They are more often found in areas with limited macrophytes and larger root aquatic plants, algae and moss. Because of their need of a specialized clean habitats, the gravel chub is especially vulnerable to various forms of pollution, especially from agriculture practices that create erosion and excessive silt. In past sampling surveys the gravel chub had been found as far north in the Upper Iowa River as Le Roy, Minnesota, but because of excessive amounts of sewage, pesticides and sedimentation of rocks and sand, this is no longer the case. The presence of gravel chubs in a
Silt, Colorado Silt, Colorado Silt is a Statutory Town in Garfield County, Colorado, United States. The population was 2,930 at the 2010 census, up from 1,740 at the 2000 census. A post office called "Silt" has been in operation since 1898. The community was named for the silt deposits at the original town site. Silt is located at (39.546316, -107.652072), on the north side of the Colorado River about west of Denver. Interstate 70 passes through the town as it follows the river, with access from Exit 97. Glenwood Springs, the county seat, is to the east, and Rifle is to the