2010-12-17_REVISION - C1981019 (161)

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subtle changes in elevation, topography, or soil porosity (usually 12 or less inches of elevation) which has resulted from historic fluvial erosion and deposition processes along the stream banks. These wetlands are characterized by a series of related vegetation communities variably dominated by a variety of taxa (see Table 1) and include: Canada thistle (Cirsium arvense), water sedge (Carex aquatilis), bentgrass (Agrostis alba), cattail (Typha latifolia), Baltic rush (Juncus balticus), cutleaf coneflower (Rudbeckia laciniata), Canada goldenrod (Solidago canadensis), Kentucky bluegrass (Poa pratensis), boxelder (Acer negundo), Nebraska sedge (Carex nebracensis), coyote willow (Salix exigua), reed canarygrass (Phalaris arundinacea), and hardstem bulrush (Schoenoplectus lacustris). Soils in the slightly higher topographic positions (transitional uplands) exhibit matrix chromas ranging from 2 to 3 and were never saturated and never exhibited mottling. Underlying materials along stream courses were typically a much brighter chroma value due to their nature as alluvial deposits (sands and small gravels). As elevation subtly decreases to the transitional wetlands of lower topographic positions, soils were more moist and exhibited slightly darker matrix chromas and bright mottles ranging from few to very abundant. At the lowest levels within the best wetland areas, soils are saturated to the surface or exhibit ponding, exhibit distinct mottles and a tendency toward gley colors at deeper profile depths. Typically wetland transition zones are comparatively narrow where obvious topographic differences occur. However, on occasion transition zones are quite broad forming a continuum where topographic changes are quite subtle as exemplified within the larger wetland units, especially Wetland # 4 that is in transition to upland. Soils in these transition zones have dark chroma colors but are not mottled or gleyed on the upland side within the upper 12 inches of the profile, which may reflect the somewhat excessively drained gravelly, loamy sand, or sandy loam nature of the subsurface soil textures often observed. Water tables associated with these upland transitional zones were observed to be seasonal and below 12-18 inches. On the wetland side, soils matrix chromas are slightly darker, mottles are present and often abundant, and the water table reaches the surface or near surface on a seasonal basis. 3.3 Results of the Delineation Survey General The following text, mapping, and tabular information documents the results of the 2005 delineation survey for the 13,605 acre vegetation study area and discusses data from sample points and other site- specific investigations. Mapping of delineated wetlands and WUS is presented on a series of five maps at the rear of the document (map pockets). These maps indicate the delineated wetlands and WUS against a photo base, and due to the small scale (owing to the large acreage of the study area), most streamside wetlands appear as a linear feature on mapping. In total, 55.49 acres were delineated within CC???cC nmv , INC. Page 8 Colowyo Coal Co. - Collom Project Wetlands