2018-06-05_PERMIT FILE - C1981019A (8)

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RULE 2 PERMITS floodplain at the northernmost portion of the mining area portion of the study area. The second is along the disassociated 22 acre haul road crossing area. The bottomland type is comprised of a variable mixture of communities - primarily sagebrush, but also grassland, mountain shrub, riparian woodland, and small stream -side wetland communities that exist intermittently along the historic floodplain of Wilson Creek. These community extensions into the alluvial and colluvial drainage bottom soils have been segregated from their upland progenitors and renamed (as Bottomland) because of the typical increase in productivity characteristic of this geomorphic landform. Within the study area, the bottomland community exhibits an occasional overstory deciduous boxelder tree (Acer negundo), and a shrub stratum strongly dominated by Mountain big sagebrush with various areas of herbaceous subdominance by cheatgrass (Bromus tectorum), Great Basin wildrye (Elymus cinereus), and western wheatgrass. A very narrow ribbon of wetland occurs along each bank of Wilson Creek through both segments of the study area. This small palustrine emergent persistent wetland community has been separately delineated and evaluated for COE 404 permitting. Dominant vegetation along this narrow wetland corridor include: Baltic rush (Juncus balticus), broad-leaved cattail (Typha latifolia), spikerush (Eleocharis palustris), Nebraska sedge (Carex nebrascensis), redtop (Agrostis alba), and bulrush (Schoenoplectus lacustris). A total of 30 species were observed within the non -wetland portion of the bottomland community with a distribution of 15 grasses, 9 forbs, and 5 shrubs or trees. Average ground cover of vegetation (2005) within the study area was 54.67% with 0% rock, 30.0% litter, and 15.3% bare ground exposure. Dominant species included: western wheatgrass, Mountain big sagebrush, cheatgrass, Sandberg bluegrass (Poa secunda), needle and thread, bluegrass, and Indian ricegrass (Oryzopsis hymenoides). The number of perennial herbaceous species exhibiting between 3% and 50% relative cover (composition) was determined to be 5 grasses and 0 forbs. Cropland (LU) - A very small amount (3.12 acres) of dry -land cropland is included in the northern 22 - acre segment of the Study Area (Wilson Creek haul road crossing). This cropland is planted to winter wheat in alternating years (average of 30 bushels/ac/yr) and is fallow when not planted to wheat. This field was fallow in 2005. Stock Tank (LU) - Two very small stock tank watering facilities (stock ponds) occur in the study area but are largely devoid of vegetation due to livestock / wildlife trampling. The uppermost stock tank exhibits a very small amount of wetland vegetation near the small spring that feeds this facility and along the outfall structure. However, this wetland area can be measured in square feet (i.e., —200 ftz) rather than acres. These stock tank areas occupy a total of 0.27 acres. Justification for Reference Area Selection ASPEN REFERENCE AREA Colowyo does not propose using the Aspen Reference Area established by Harrier and Associates, in 1984 for the Danforth Study (ST -ARA) at this time. SAGEBRUSH REFERENCE AREA Colowyo will use the originally established Sagebrush Reference Area (C -SRA -1981) for weighted future revegetation success comparisons in the Lower Wilson disturbance areas. Colowyo will use the C -SRA South Taylor/Lower Wilson— Rule 2, Page 56 Revision Date: 11/18/16 Revision No.: MR -163