2012-01-06_PERMIT FILE - C1982057 ‎(16)‎

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 1/6/2012
• Section_Exhibit Name: TAB 09 SOIL BASELINE STUDY
• Media Type: D
• Archive: No

Soil Setting. The dominant soils in the study area occur on three types of parent material and
• landform combinations; upper sideslopes, ridges, and swales oT sandstone residuum; toeslopes,
sideslopes, rounded ridgetops of shale residuum and colluvium; and toeslopes, sideslopes,
ridges, and escarpments of sandstone and shale.
The soils formed from sandstone residuum and colluvium occur on moderately sloping to very
steep slopes 15 to 70 percentl. The soils range from 10 to more than 60 inches deep with the
average depth being approximately 35 inches. Soils are shallowest on the upper sideslopes and
ridges and deepest on benches, toeslopes, and swales. The surface horizons are generally silt
loam, loam, and sandy loam ranging from 10 to 30 inches deep. The surface horizons of
Splitro and Winevada lie directly over highly fractured sandstone bedrock. The subsoils of
Coutis and Skyway are weakly developed over highly fractured sandstone bedrock. The subsoil
of Foidel is strongly developed and consists of silt loam and silty clay loam. The soils on these
sandstone landscapes occur as consociations or as complexes with other soils. The presence
of any one particular soil is governed strongly by the soil depth to weathered rock.
The soils occurring on toeslopes, sideslopes, and rounded ridgetops of shale formed in
residuum end colluvium. Slopes range from 10 to 50 percent. The average soil depth is about
50 inches. Surface horizons range from about 5 to 20 inches and consist of clay loam, silty
clay loam, silty clay, and clay. The subsoils of Aaberg and Binco are moderately developed
• over highly weathered clay, silty clay, and shale. The subsoils of Buckskin, Cochetopa, and
Routt are strongly developed and consist of clay loam, silty clay, and clay. Sagebrush is the
dominant vegetation type on the very fine clay textured Aaberg and Binco soils. Aspen,
snowberry, and serviceberry predominate on the fine clay textured Cochetopa, Routt, and
Buckskin soils.
The soils occurring on toeslopes, sideslopes, ridges, and escarpments of sandstone and shale
formed in colluvium and residuum. Slopes range from 50 to 70 percent with areas of rock
outcrops occurring as ledges in the unit. The average soil depth is approximately 15 inches.
Soils are very thin to nonexistent on the escarpments and thickest on the toeslopes below the
escarpments. The surface and substratum of these soils ICryoborolls, Lymanson, Lymanson
Variant, Roxal Variant, Starman, Teton, and Ustic Torriorthentsl consist of fine sandy loam,
loam, channery to extremely channery clay loam, very stony sandy loam, gravely clay loam,
and silty clay loam overlying highly weathered sandstones and shales at varying depths. The
distribution of soils within this unit is closely associated to the type of parent material present;
consequently, these soils occur in a complexly intermingled pattern.
•
23 Revised 9/98