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
Gravel Run (Susquehanna River tributary) the United States Geological Survey quadrangle of Riverside. The stream is one of the main streams in Northumberland County. Gravel Run has been contained in Northumberland County since the county was formed in 1772, when Pennsylvania was still a colony. At the time, it was located in Augusta Township, but in 1785, Catawissa Township split off from Augusta, with Gravel Run part of the border between the two. Three years later, in 1788, Ralpho Township split from Catawissa, and included the land that bordered Augusta; Ralpho was renamed Shamokin a year later. In 1819, Rush Township was created by splitting