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<br />CNAPTERTHREE Affected Environment <br />' low available water capacity. Slopes aze 9 to 75 percent. Water erosion hazard is slight to severe <br />and wind erosion hazard is slight. Limiting factors include steep slopes, shallow rooting depth, <br />and very little available water for use by plants. These soils are considered fragile. <br />The Rock outcrop-Torriorthents complex is on the rock escarpment and colluvial slopes along <br />the edge of the Roan Plateau. Rock outcrop is mainly Green River shale and makes up about 50 <br />to 80 percent of the complex. Torriorthents aze shallow to moderately deep clays to loams with <br />variable amounts of gravel, cobbles, and stones. Water erosion hazard is moderate to severe, and <br />increases with increasing slope steepness. Wind erosion hazard is moderate. Extremely steep <br />slopes, shallow rooting depth, and rockiness are limiting factors. These soils are considered <br />fragile. <br />Within the Pazachute Creek Valley, the pipeline corridor generally stays in Nihill channery loam, <br />which is located on both sides of Parachute Creek all the way to the Parachute Site. Nihill <br />channery loam is on nearly level to moderately sloping alluvial fans and sides of valleys. It is <br />deep, well drained soil with moderately rapid permeability and low available water capacity. <br />Slopes range from 1 to 25 percent. Water erosion hazard is moderate to severe and the hazard of <br />wind erosion is slight. The main limitation is erosion on the steeper slopes (SCS 1985). These <br />soils could be fragile on the steeper slope where water erosion hazard is severe. <br />Parachute Sife <br />The Parachute Site would be located at the existing Unocal facility where most soils have ah•eady <br />been disturbed. It is situated in the Pazachute Creek Valley and contains the following soil units: <br />Nihill channery loam, Torrifluvents, Olney loam, Heldt clay loam, and Arvada loam. Nihill <br />channery loam is described above. Nihill soils comprise 61 acres (20 percent) of the Parachute <br />Site. Torrifluvents, also described previously, comprise 46 acres (15 percent) of the Parachute <br />Site. Olney loams are on alluvial fans and sides of valleys. They are deep, well-drained soils <br />with moderate permeability and moderate available water capacity (SCS 1985.) Slopes are 1 to 6 <br />percent. Water erosion hazard is slight to moderate, and wind erosion hazard is slight to very <br />slight. These soils may be a good source of reclamation material. These soil units comprise 47 <br />acres (16 percent) of the Parachute Site. <br />Arvada loams are also located on fans and high terraces. They are deep, well drained soils with <br />very slow permeability, and moderate to high available water capacity. Slopes are 1 to 20 <br />percent. Water erosion hazard is moderate to severe and wind erosion hazard is moderate. These <br />soils are moderately saline, and this erosion potential are the main limiting factors for this soil <br />type (SCS 1985). These soil units comprise 130 acres (43 percent) of the Parachute Site. <br />Heldt Clay loams are located on alluvial fans and sides of valleys. They aze deep, well drained <br />soils with slow permeability, and moderate available water capacity. Slopes are ] to 3 percent. <br />Water erosion and wind erosion hazard is slight. Excessive clay is the only limiting factor for <br />this soil type (SCS 1985). This soil unit comprises 20 acres (6 percent) of the Parachute Site. <br />Soils 3-11 <br />