2010-12-30_PERMIT FILE - P2010026 (5)

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of water erosion is moderate to high. Redcreek is considered Highly Erodible Land (HEL) for both wind and water erosion. 0 Rentsac channery loam (in Map Units 70, 73, and 75) is a shallow, well drained soil on ridges, foothills, and sideslopes. Rentsac soils formed in slope alluvium and colluvium over residuum derived from calcareous sandstone. The native vegetation is mainly pinyon and juniper trees, with an understory of shrubs and grasses. Rentsac is classified as a "Loamy-skeletal, mixed, superactive, frigid Lithic Calciustepts". Rentsac soils comprise approximately 80% of map unit 73. However, Rentsac occurs as a minor component of the Redcreek-Rentsac complex (map unit 70) and a major component of the Rentsac-Piceance complex (map unit 75), occupying 30% and 60% of these map units, respectively (Soil Survey Staff 2009b). Other soils series that may occur within these map units include Blazon, Forelle, Moyerson, Piceance, Redcreek, Yamac, and Rock outcrop. By using these percentage estimates, we can assume that approximately 44 acres of Rentsac soils occur in map units 70, 73, and 75 within the study area. The representative Rentsac channery loam sample site was located approximately 426 feet east, 1,095 feet south of the NW corner of Section 4, T2S, R98W. The landscape at the sample site was a 3% slope with a northwest aspect. Vegetation included mainly shrubs and mixed grasses, with a few pinyon pine and juniper trees. Void of significant vegetative cover, the soil surface was exposed and the fine sandy loam was loose. However, there was no visible evidence of significant disturbance or significant erosion. 0 The Rentsac soil typically has an "A" horizon surface layer that is grayish brown channery fine sandy loam approximately 2 inches thick with 20 to 35 percent rock fragments, most of which are less than 3 inches across. The underlying "Bkl" horizon consists of very channery loam or sandy loam approximately 5 inches thick with 30 percent sandstone channery fragments and 10 percent flagstones. The "Bk2" horizon substratum is extremely flaggy loam about 7 inches thick with 80 percent sandstone channery fragments and flagstones 2 to 10 inches in diameter and 1 to 2 inches thick. Hard sandstone underlies Rentsac at a depth of approximately 16 inches. Depth to sandstone ranges from 10 to 20 inches. Runoff is rapid, permeability is moderately rapid, and the hazard of water erosion is moderate to very high. Map units that contain Rentsac (map units 70, 73, and 75) also meet Highly Erodible Land (HEL) criteria for severe wind and water erosion hazard (HEL Wind, and HEL Water), with the exception of map unit 73, which does not meet HEL Water criteria. Yamac loam (in Map Unit 104) is a deep, well drained soil mapped on rolling uplands, terraces, and alluvial fans. Yamac soils formed in eolian and alluvial material from mixed sources. The native vegetation is mainly shrubs and mixed grasses. C? 7