2014-06-26_PERMIT FILE - M2014027 (2)

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ROCK OUTCROP This unit consists of about 90 percent bedrock outcrops and ten percent shallow and very shallow soils on very steep slopes. The most important soil characteristics are shallowness and stoniness. The exposed bedrock consists of tuff, rhyolite, andesite, breccia, and other volcanic rocks. Slopes range from about 30 to more than 100 percent. Effective rooting depth is limited by depth to bedrock in the areas where soil is present. Available water holding capacity is low. Surface runoff is rapid and erosion hazard is moderate. SEITZ VERY STONY LOAM This deep soil occurs on moderately steep to very steep (15 to 65 percent) slopes on mountain sides and ridges. It developed in slopewash materials derived from igneous rocks at elevations of 9,000 to 9,800 feet. Included in this unit are a few small areas of Bushvalley and Comodore soils. Typically, there is a thin organic layer consisting of partially decomposed needles,twigs, and grass on the surface. This layer overlies a dark grayish brown, very stony loam surface clay about two inches thick. The subsurface layer is a pale brown, very stony loam about four inches thick. Subsoil is a brown or yellowish brown,very stony clay or heavy clay loam about 24 inches thick. The substratum is a yellowish brown, extremely stony clay loam that extends to 60 inches or more. Permeability is low. Effective rooting depth is 60 inches or more. Available water capacity is moderate. Surface runoff is moderate and the erosion hazard is moderate. COMODORE-ROCK OUTCROP COMPLEX These soils occur in the mountainous area of Saguache County on slopes of 40 to 150 percent grade or more. Comodore soils make up about 55 percent and rock outcrop about 45 percent of the mapping unit. Comodore soil is ten to 20 inches thick over bedrock. The rock outcrop occurs as large, steep mountainous areas of exposed rhyolite and closely associated volcanic and agglomeratic materials. The Comodore is a shallow, well-drained, very stone (35 percent) soil, formed in thin colluvial material from igneous and metamorphic rock. Typically, the surface layer is very stony loam about five inches thick. The underlying material is extremely stony loam about 120 inches thick and is directly over hard igneous or metamorphic bedrock at ten to 20 inches depths. Permeability is moderate. Effective rooting depth ranges from ten to 20 inches. Available water capacity is moderately low. Surface runoff is rapid and erosion hazard severe.