Unified Soil Classification System group symbol. For example, GW-GM corresponds to "well-graded gravel "with silt"." If the soil has more than 15% by weight retained on a #4 sieve (R > 15%), there is a significant amount of gravel, and the suffix "with gravel" may be added to the group name, but the group symbol does not change. For example, SP-SM could refer to "poorly graded SAND with silt" or "poorly graded SAND with silt and gravel." Unified Soil Classification System The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size
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.