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Th <br />l <br />th <br />d f th <br />lk <br />h <br />fi <br />W <br />Dit <br />ti th th <br />b nd <br />hi • <br />an <br />scape nor <br />e sa <br />es <br />o <br />e <br />a <br />er <br />c <br />s o <br />e geomozp <br />c a <br />irrigation criteria o£ an alluvial valley floor. The land is currently used for <br />grass hay and alfalfa production. <br />Coal handling operations at the Loadout will not intercept any alluvial valley <br />floor areas. The existing rail cuts are through upland terraces and hillslopes <br />which are used for rangeland and wildlife habitat. The Loadout operations and <br />reclamation plan will minimize disturbances to the hydrologic balance by <br />preserving the essential hydrologic functions of the alluvial valley floors <br />adjacent to, and downstream of the Loadout facility. The operations will not <br />interfere or impede the valley floor area's ability to collect, store, and <br />regulate the natural flow of surface and groundwater. <br />The quality of the surface and groundwater supplying the alluvial valley floors <br />will not be impacted by Loadout operations to such an extent that the water uses <br />(irrigation and stock water) are precluded or so severely degraded in comparison <br />to background levels that material damage occurs. Appendix 7-2, Dry Creek <br />Alluvial Groundwater Evaluation shows that the regional alluvial groundwater can <br />be generally characterized as "of limited use and quality". <br />Appendix 7-2 describes alluvial groundwater data collected by a corporate <br />affiliate in 1997 and 1998. The data indicate that the alluvial groundwater <br />upstream of Stokes Gulch is of "potentially usable quality" - total dissolved <br />solid (TDS) concentrations ranged £rom 4,200 milligrams per liter (mg/1) to 9,880 <br />mg/1. Horon concentrations were at, or just below the agricultural use standard <br />(0.75 mg/1). Stokes Gulch alluvial groundwater contained TDS concentrations in <br />excess of 33,000 mg/1, which is significantly higher than the 10,000 mg/1 <br />threshold used to classify a groundwater as "limited use and quality". <br />Constituent concentrations in a monitor well located east of the Loadout facility, <br />which monitors alluvial groundwater flowing from the upland farm area in Section <br />23 southeast o£ the Loadout facility area, also exceeded agriculture water quality <br />thresholds. TDS concentrations in two water quality samples were 37,500 and <br />38,100 mg/1. <br />Surface water data collected in 1997 and 1998 support the "limited use and <br />quality" characterization of the alluvial groundwater. A surface water site on <br />lower Stokes Gulch, had TDS concentrations of 10, 300 and 6,860 mg/1. An un-named <br />TR-07 14-3.5 Revised 03/06 <br />