2011-09-19_REVISION - M1982155 (17)

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Soil Information EXHIBIT I At the end of this exhibit are some printouts from the NRCS website that describe many of the typical characteristics of the soils present on the site. Please refer to Exhibit C -3, Soils Map, for an illustration showing the distribution of the soils. Most of this exhibit will concentrate on the soil characteristics of the site itself. Although a particular location may be mapped as a certain NRCS soil series or form, it does not necessarily mean the soil is typical for that series or form. Local factors may alter some of those characteristics. General Soil Type The uplands at this site are occupied by the Fort Collins loam. This soil is noted for its depth, excellent growth potential, and high productivity when growing conditions are good. It is a non - saline soil with about a 15% calcium carbonate content which causes a somewhat alkaline reaction with a pH of about 7.8 to 8.5. That pH is common in soils on the Colorado plains and is not limiting to adapted vegetation species. Typically there is a clay loam layer at about 9 to 21 inches, with a loam surface layer. At the proposed amendment site the loam surface layer appears to have been partially lost due to past overgrazing and wind erosion. As a result, the surface soils appear to be somewhat more clayey that would normally be expected with the Fort Collins loam. It still produces very good growth as evidenced by the vegetation, but productivity is probably less than would be found on excellent Fort Collins loam. These soils are restricted to the highest elevation, nearly level portions of the site. As the valley edge is approached, the topography becomes a bit more sloping and the loamy Fort Collins soil gives way to the Stoneham sandy loam. The transition between these two soils is very broad with soil texture becoming more and more sandy as the Stoneham replaces the Fort Collins loam. At the start of the transition this soil is very deep and exhibits only slightly less productivity than the Fort Collins loam, but where the Stoneham sandy loam is close to the Schamber -Razor complex, the Stoneham thins rapidly and becomes much less productive. The Schamber -Razor complex forms the edge of the valley and the slopes leading down into the Rock Creek valley. Although the typical soil of this type exhibits a gravelly loam topsoil about five inches thick, the soil on the proposed amendment area lacks much topsoil. For the most part, topsoil is only barely identifiable with the deeper very gravelly loam and very gravelly sand being most commonly exposed on the surface. Once again, this is probably due to wind erosion removing the fines, which probably occurred as a result of past overgrazing. There appears to be some local soil replacement occurring as fines from the Stoneham and the Fort Collins soils are washed downslope onto the Schamber -Razor soils. The slopes in the proposed amendment area are primarily occupied by the Schamber soils. The Razor soils tend to appear further down the slopes, more toward the toe as they are derived from the clays that underlie the gravel deposit from which the Schamber soil developed. The Razor Fountain Pit M- 1982 -155 DRMS 112 Permit Amendment Page 20