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 west. U.S. Route 6 is Main Street in Silt, and provides a local route parallel to I-70. According to the United States Census Bureau, the town has a total area of , of which , or 1.46%, is water. This climatic region is typified by large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold) winters. According to the Köppen Climate Classification system, Silt has a humid continental climate, abbreviated "Dfb" on climate maps. As of the census of 2000, there were 1,740 people, 648 households, and 452 families residing in the town.