Silt In the Unified Soil Classification System (USCS) and the AASHTO Soil Classification system, the sand–silt distinction is made at the 0.075 mm particle size (i.e., material passing the #200 sieve). Silts and clays are distinguished mechanically by their plasticity. Silt is easily transported in water or other liquid and is fine enough to be carried long distances by air in the form of dust. Thick deposits of silty material resulting from deposition by aeolian processes are often called loess. Silt and clay contribute to turbidity in water. Silt is transported by streams or by water currents in the ocean. When
Gravel chub type of habitat, increasing the turbidity of the current and the amount of silt in rivers and streams. Populations in southern Minnesota are experiencing a great amount of stress due to the large amount sediment deposit from the Mississippi River that disturbs flow regimes. The Minnesota DNR has been continuing to monitor and improve water quality of rivers and streams in southern Minnesota. Iowa and New York also have put extra conservation efforts towards the gravel chub. In Iowa the gravel chub was once threatened, but now abundant all over the state. In New York there has been a strong