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soils on Gunnison National Forest lands within the SGFA. As a consequence of the <br />numerous mapping efforts by the different agencies and changes in official <br />nomenclature by the NRCS; mapping, soil unit terminology, and description of soils in <br />the vicinity of the mine has been inconsistent. For the purposes of this study, soil <br />mapping and nomenclature follow that presented in the Soil Survey of Paonia Area. <br />Colorado. Harts of Delta. Gunnison and Montrose Counties (USDA/SCS, 1980). <br />Within the Gunnison National Forest, the USFS soil map units have been revised in <br />this report as necessary to reflect comparable NRCS soil designations. <br />Based on the 1996 field reconnaissance and sampling, one soil series, one soil <br />association, one soil complex, and one general classification were identified as present <br />in the area slated for significant disturbance in the SGFA (Figure 1). Work loam was <br />identified within outwash terraces and swales located adjacent to Sylvester Gulch. The <br />Beenom-Absazokee association was located along the lower sideslopes and tceslopes of <br />Sy]vester Gulch along the length of the drainage. The Torriorthents-Rock outcrop, <br />sandstone complex was mapped predominantly on the steep east-facing slope above <br />Sylvester Gulch. Fluvents were locally mapped within the drainage and immediately <br />adjacent area of Sylvester Gulch. This soil unit is restricted to areas where surface <br />flow and attendant deposition and scouring are present. <br />Three additional soil map units were identified within the study area but outside the <br />• areas of significant disturbance. These units included the Absazokee-Work loam <br />association, and the two broadly defined units, Cryochrepts-Cryoborolls-Rubble land <br />complex, and Haploborolls-Ustochrepts-Rock outcrop complex. <br />Brief descriptions of these soil units from the 1996 soil survey follow. <br />WORK LOAM <br />Work foams are deep, well-drained soils found on alluvial fans and valley-filling <br />footslopes. They are formed in reworked alluvium from weathered sandstones and <br />interbedded shales. Work foams aze common on slopes grading from three to twenty- <br />five percent. Surface layers of this series aze typically a dark brown loam averaging <br />six inches thick. Subsurface layers are brown foams or clay foams approximately 33 <br />inches deep, which grade into a deep stony loam (up to 60 inches). Native plants <br />associated with this series are wheatgrasses, bluegrasses, bromes, oakbrush, and <br />serviceberry. Work foams are often used for grazing with occasional use by wildlife. <br />This soil is not suited for non-irrigated crops due to low annual precipitation. <br />Permeability is slow, and surface runoff on unprotected or non-vegetated surfaces is <br />rapid. This soil is not particulazly susceptible to wind erosion. NRCS places this soil <br />in capability subclass VIe, soils with severe erosion limitations, making them generally <br />unsuitable for cultivation. <br />• <br />_~ <br />