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In the tipple azea, the Illinois River has a base flow rate of about six cubic feet per second (cfs) and <br />a recorded 100-yeaz flood discharge of 2970 cfs. The Illinois River has its source in the Never <br />Summer Range to the southeast. The Illinois River, after passing the tipple area, flows in a <br />northwest direction and bypasses the town of Walden on the southwest. Approximately one-mile <br />northwest of Walden, the Michigan River merges with the Illinois River. The Illinois River in turn <br />flows north to merge with the North Platte River. <br />Just to the east of the tipple area, the groundwater level is expressed in a stagnant pond. This water <br />level is very neaz to the original land surface. The water level in this pond is maintained by water <br />from the Illinois River flowing through alluvium, and from snowmelt and thundershowers. The <br />water in the pond is predominantly a calcium and bicarbonate type that is alkaline in nature and low <br />in dissolved and suspended loads. <br />Soils of the Marr Mine azeas aze predominately sandy clay loam and clay textures (Table 42a in the <br />pemilt application). The 720 Pit soils consist of mainly Coahnont clay, Aaberg-Banishment <br />complex clays, and areas of very minor Fluetsch sandy clay loamy. The Coahnont soils aze <br />classified as fine, montmorillonitic Borollic Camborthids and fine, montmorillonitic Borollic <br />Paleazgids, respectively. Fluetsch soils aze classified asfine-loamy, mixed Borollic Haplazgids. All <br />of these soils have high clay contents. The Pit 1 soils consist of Coalmont clays and Cryorthents <br />(clayey in this case), with all soils having clay percentages of 50 or more. Pit 2 soils consist of <br />Coalmont sandy clay loamy and Cryorthents with surface clay overlain on sandy clay subsoil. Pit 3 <br />soils are mainly Gelkie sandy clay loams (fine-loamy, mixed Argic Cryoborolls). Some minor <br />amounts of Coalmont sandy clay loamy also occur in the Pit 3 azea <br />Topsoil suitability ratings aze listed in Table 43a of the permit application. In general, all soils in <br />the Pit 1 azea aze rated as poor as topsoil sources because of high clay content. Pit 2 soils aze rated <br />good except for Cryorthents, which aze rated as poor because of the high clay content (surface soil) <br />or high SAR (subsoil). Pit 3 soils aze generally rated as good topsoil sources. The 720 Pit azea was <br />stripped of topsoil between 1974 and the March 20, 1981, permit issuance, so a six-inch layer of <br />topsoil was saved and stockpiled regazdless of the suitability rating. <br />Soils in the area of the tipple were not removed prior to construction, since the tipple was built prior <br />to the existence of topsoil salvaging requirements (page 780-64). Additionally, fill material of a <br />sandy loam to loamy sand texture was brought in to improve foundation material, drainage and <br />elevation, due to the proximity of the water table to the surface. Therefore, soil at the site was <br />either buried or used to construct the berm that surrounds the site to the south and east. <br />Vegetation <br />The vegetation at the Marr permit azea is described as a sagebrush steppe. Big sagebrush <br />(Artemisia tridentate) predominates most azeas, although alkali sagebrush (Artemisia longaloba) <br />communities aze found. Absolute cover at the site ranges from 35 to 45 percent. Sagebrush and <br />rabbitbrush make up 60 percent of the relative cover while forbs and grasses equally split the <br />remainder. Phlox is the predominant forb and wheatgrasses aze the major grasses. Productivity <br />ranges from 450 to 750 pounds per acre. <br />Marr Mine Permit Renewa105 17 March 2006 <br />-~ n- <br />