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Soils <br />The soils within the permit area are highly variable in depth and quality. Soils mapped in swales <br />and north-facing slopes aze generally deep and well-drained sandy loams, neutral to slightly <br />alkaline, with moderate amounts of organic matter. Several areas of saline and/or sodic topsoil <br />were located in the permit area. These saline and sodic soils are unsuitable for reclamation. <br />Vegetation <br />The site is located in the intermountain park climax region. Two vegetation types occur within <br />the mine site area; a dry grassland community, and a big sagebrush shrub community. The dry <br />grassland type occurs on south-facing slopes and within swales. Dominant life forms are cool <br />season grasses and low shrubs. The big sagebrush community occurs on a variety of exposures <br />and soil types. Dominant life forms are shrubs and semi-shrubs. Vegetation cover ranges from <br />9% (grassland) to 30% (big sagebrush shrubland), while production ranges from 1271b/acre <br />(grassland) to 9501b/acre (big sagebrush shrubland). <br />Description of the Hydrologic Environment <br />Surface Water <br />Mann Draw is an intermittent stream with a total drainage azea of 3.39 square miles (2,170 <br />acres). An estimate of the average annua] runoff was made by Leonard Rice Consulting Water <br />Engineers, Inc. The estimated flow was obtained by multiplying the adjusted unit runoff value <br />for Williams Draw, 0.049 acre-feet per acre, by the total area of Mann Draw. The resulting <br />estimate was 106 acre-feedyeaz. There is one stock pond located on Mann Draw, about 2,000 <br />feet downstream of the Bourg Strip Mine. The Bourg Mine is 1.85 miles upstream of the <br />confluence of Mann Draw with the Canadian River. <br />Alluvial Valley Floors <br />Two areas were identified within or adjacent to the mine that meet the geomorphic criteria of <br />alluvial valley floors. Deposits of unconsolidated alluvial materials were identified along Mann <br />Draw and at the confluence of Mann Draw and the Canadian River. However, only the alluvium <br />on the Canadian River located 1.7 mile below the mine site, met the hydrologic criteria for an <br />alluvial valley floor. <br />Bourg Strip Mine. C-81-OZ 1 7 August 4, 1998 <br />