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<br />• for approximately two miles. The pipeline corridor then proceeds south along the <br />ridgetop between the Middle Fork and East Fork of Stewart Gulch (Barnes Ridge) <br />where the dominant soil is the Redcreek-Rentsac complex (SCS 1982). The pipeline <br />corridor then crosses one drainage to the east where it remains on top of a ridge all <br />the way to Davis Point, in this section being situated in Parachute-Rhone loams. <br />The Parachute-Rhone loam soil type is typically deep and well drained, with <br />moderate permeability (SCS 1985). As the pipeline corridor moves down along <br />Davis Point, it crosses Irigul channery loam and the Torriorthents-Rockoutcrop <br />complex (described above), which is very steep (SCS 1985). Irigul channery loam is <br />shallow, well drained, and moderately permeable. <br />Within the Parachute Creek valley, the pipeline corridor generally stays in Nihill <br />channery loam, which is located on both sides of Parachute Creek all the way to the <br />Parachute Site (SCS 1985). Nihill channery loam is deep, somewhat excessively <br />drained soil located on toe slopes and terrace edges (SCS 1985). This soil is typically <br />quite rocky and has moderately rapid permeability. <br />Parachute Site <br />The preferred Parachute Site would be located at the existing Unocal facility, which <br />is situated in the Parachute Creek valley and contains the following soil units: <br />Nihill channery loam, Olney loam, and Arvada loam. Nihill channery loam is <br />described above. Olney loam is deep, well-drained, nearly level soil located on <br />alluvial fans and valley sides (SCS 1985.) Arvada loam is also deep, well-drained <br />soil and is located on fans and high terraces (SCS 1985.) Typically, the surface layer <br />of this soil is strongly alkaline. In addition, this soil is limited as a source of <br />construction material by its high shrink-swell potential and salinity. <br />Much of the soil at the preferred Parachute Site has already been disturbed by <br />development of the existing Unocal facility in the early 1980s. <br />7.3 SURFACE WATER AND SURFACE DRAINAGES <br />7.3.1 Surface Water Hydrology <br />Piceance Creek Watershed <br />The upper two-thirds of the project area is located in the Piceance Creek watershed. <br />Except for Piceance Creek, which is perennial, all streams in the vicinity of the <br />Piceance Site and all streams intersected by the pipeline corridor are ephemeral. The <br />watershed covers 629 square miles and is part of the White River drainage basin. <br />Piceance Creek flows into the White River approximately 15 miles north of the <br />Piceance Site. The White River is tributary to the Green River, which is a tributary <br />of the Colorado River. Surface water in the watershed originates primarily as spring <br />• (April through June) snowmelt runoff. The main annual flooding events come <br />from snowmelt and from extreme summer (primarily August) thunderstorms <br />American Soda, L.L.P. '7_14, <br />Commeraal Mine Plan <br />August 16, 1996 <br />