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RULE 2 PERMITS <br />Preliminary map unit boundaries were identified in the field were supported by available data and site <br />inspection. Boundaries of preliminary map units were further refined based on the results of pedon <br />descriptions and development of conceptual map units. Many of the conceptual map units were <br />documented in the field for further refinement based on review of all available information, including <br />laboratory results and final pedon classifications. <br />Following completion of the field effort, additional refinement was made using high - resolution, color <br />satellite images with a false -color infrared display. This image revealed more detail related to vegetation <br />communities, outcrop patterns, and early fall soil moisture levels. The second resource was development <br />of hillshade models to simulate the accumulation of loess deposits in the Soils Survey Area. This simple <br />tool visually simulates those areas most likely to accumulate loess with various prevailing winds. In <br />combination with one another, these resources dramatically improved the accuracy and precision of the <br />survey. <br />Each map unit within the Soils Survey Area was described by documenting soil series and families found <br />in the map unit, their relative composition, and their placement relative to one another. Map units <br />produced as part of this survey were composed primarily of consociations and complexes, with the smallest <br />units approximately 0.5 acres in size. <br />Pedon descriptions were updated with the results of laboratory analysis, where available, and classified <br />first to the family level and then correlated to series identified as major components of NRCS map units <br />within five miles of the Soils Survey Area. The pedon classifications yielded 53 unique textural families, <br />including thirty series and 23 families with no corresponding series identified in nearby portions of the <br />NRCS surveys. The series identified, along with variants and taxadjuncts, represented 393 of the 456 <br />pedons (86 percent) described in the Order II Survey Area. <br />Identifying the correct soil temperature and moisture regime is critical to determining the correct <br />classification in accordance with the current Keys to Soil Taxonomy (USDA, 2006). In -depth review of <br />the NRCS survey of Moffat County (USDA 2005a) revealed significant changes in the soil temperature <br />and moisture regimes within the Soils Survey Area. Onsite evaluation of soil and vegetation and <br />discussions with Charles Peacock, soil scientist in the Craig, Colorado, NRCS soil survey office (Charles <br />Peacock personal communication with Judd Stark), confirmed that the major regime changes do exist and <br />provided insight into the likely patterns. <br />The extreme north end of the Soils Survey Area was determined to be frigid and aridic while higher <br />elevations in the southern portion of the Soils Survey Area were determined to be cryic and ustic. Entisols <br />(soils exhibiting no profile development) were not classified by regime and are shown as their own class <br />(entic). Transitional temperature regimes occurred along cryic canyon walls and shaded slopes to the <br />north and frigid plateaus to the south. The boundary between moisture regimes generally coincided with <br />the prominent ridge and high elevations in the extreme southern end of the Soils Survey Area. <br />Transitional moisture zones include aridic ridge tops and south - facing slopes, and ustic valley bottoms <br />and steep north- facing slopes. Entisols were present throughout the Soils Survey Area on steep slopes, in <br />areas of active alluvial deposition, and areas of bedrock exposure or extremely shallow depth -to- bedrock. <br />The Collom permit expansion area contains deep soils in mostly gently to moderately sloping locations on <br />the benches and drainages, shallow soils on steep slopes at the north end of the area and very deep soils <br />on steep slopes at the southern end of the area. Except for the north end of the area, the primary limitation <br />of the soils in the Collom permit expansion area is the high percentage of clay. The other primary concern <br />is a high percentage of coarse fragments and occasionally shallow depths to bedrock restricting salvage <br />depths. Soils on the northern end of the area are very deep loess derived soils with stripping depths of two <br />feet or more over large areas of north facing slopes. <br />Collom — Rule 2, Page 52 Revision Date: 9/28/11 <br />Revision No.: PR -03 <br />