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 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