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<br />• Grassland Association (Foothills Swale)
<br />The Grassland Association consists of perennial grasses, including basin wildrye,
<br />western wheatgrass, streambank wheatgrass, Nevada bluegrass, Indian ricegrass,
<br />intermixed with forbs, half-shrubs, and rather sparse shrubs. The most common
<br />shrubs are big sagebrush, rubber rabbitbrush, black greasewood, and fourwing
<br />saltbush. Available moisture, as influenced by elevation, soils, and topography, is
<br />probably the dominant factor influencing species composition, density, and diversity
<br />of stands within the Grassland Association.
<br />Native grasslands generally occur as scattered patches on windswept ridgetops, on
<br />uppermost south slopes, and on deeper soils in valley bottoms. At the Piceance Site,
<br />this community occupies north-facing slopes of the lower reaches of the dry,
<br />ephemeral drainages to Piceance Creek and appears to be restricted primarily to
<br />Barcus channery loamy sand soils.
<br />Riparian Vegetation (Riparian Wetlandsl
<br />Riparian plant communities in the vicinity of the project typically occur as narrow
<br />bands associated with small perennial streams, man-made reservoirs and stock
<br />ponds holding year-round waters, and springs. Riparian vegetation in the area is
<br />dominated by grasses (western wheatgrass, slender wheatgrass, and needlegrasses},
<br />• sedges, and rushes. Shrubs, including big sagebrush, rubber rabbitbrush, and
<br />greasewood, are present but sparse. This community occurs within the Piceance Site
<br />only along Piceance Creek, where it occupies Hagga loam and Havre loam soils.
<br />The Pinyon-Juniper Association, the Sagebrush Association, and the Barren/Rock
<br />Outcrop Association are the predominant vegetation types at the Piceance Site. A
<br />map showing the distribution of vegetation types at the Piceance Site is presented as
<br />Figure 7-17 (source: BLM 1982). A list of all plant species identified during the 1995,
<br />1996, and 1998 threatened and endangered plant surveys of the Piceance Site and
<br />adjacent areas (Young and Young 1995, Young and Young 1996, Young and Young
<br />1998) is included in Appendix 7-A. The occurrence and distribution of threatened
<br />and endangered plant species is discussed in Section 7.9.1, below.
<br />7.6.2 Pipeline Corridor
<br />The project pipeline route may be described according to three
<br />geographical/jurisdictional segments. The first segment extends from the initial
<br />processing plant at the Piceance Site (in T15, R97W, Section 19) generally southeast
<br />to the Greasewood Compressor Station, which is located on an existing north-south
<br />natural gas pipeline corridor (in T25, R96W, Section S). This first segment is
<br />approximately 9 miles long, including 2 miles that are within the Piceance Site, and
<br />primarily occupies BLM land. The last 2 miles of this segment parallel an existing
<br />• east-west natural gas pipeline corridor.
<br />American Soda, L.L.P. 7_34
<br />Commercial Mine Plan
<br />August I8, 1998
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