2010-12-30_PERMIT FILE - P2010026 (4)

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i 2.0 METHODS Soils in the study area were originally identified and mapped as part of an Order 3 survey by the Natural Resource Conservation Service (MRCS) and published in the Soil Survey of Rio Blanco County Area (Tripp et. al. revised 1992). The objective of this study is to verify and/or refine, as necessary, the original Order 3 soil survey by providing a complete and accurate Order 2 survey of the soils in the study area. The soil survey field investigation was conducted in accordance with the procedures and standards of the National Cooperative Soil Survey (Soil Survey Staff 1993; Schoeneberger et. al. 2002). The previous Order 3 soils mapping of the project area is found in the published Rio Blanco County Area Soil Survey (Tripp et. al. revised 1992) and can be accessed online at the Web Soil Survey (Soil Survey Staff 2009c). Current soil series descriptions for the study area soils were obtained from the NRCS web site (Soil Survey Staff 2009a). Other interpretative information (Highly Erodible Soils-HEL, Hydric Soils, and Prime and/or Important Farmland status) had been obtained previously from the NRCS office in Meeker, Colorado (MRCS 2001; Sanders 2009). In July 2009, an Order 2 soil survey was conducted at the study area by Kari Sever, Certified Professional Soil Scientist (ARCPACS #33320). The entire area was traversed on foot. Previous soil map units, as delineated on the NRCS photo-base map, were observed in the • field by exposing soil profiles using a sharpshooter and bucket auger, as well as observing surface conditions, vegetation, slope gradient, and slope aspect. Map unit boundaries were identified at closely spaced intervals. High quality aerial photographs (1 meter resolution) of the project area were used during the soils field work (USDA 2009). As a part of this Order 2 survey, all major soils found in the study area were described. Two (2) representative samples were collected and analyzed for each soil series within map unit delineations. Representative composite samples from 5 map units were collected from the surface and subsurface at depths of 0-4 inches and 12-18 inches respectively. The composite samples were collected from a minimum of 4 random sample holes located within 4 feet of a central location inside the map unit delineation. The central sample locations were recorded using GPS technology and are shown on Figure 2 - Soils Map and Sample Locations. Surface samples were combined and mixed in a clean plastic bucket. A pint-sized amount of soil was then placed in a clean plastic bag and labeled for submittal to the analytical laboratory. Composite subsurface samples were collected from the same holes as the surface samples and treated in the same manner. • 2