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CAM concluded that sediment ponds will improve the quality of the surface water <br />flowing through and out of the proposed permit area and adjacent area because <br />sediment and water removed from the ponds will be disposed of at an approved <br />disposal facility. This will reduce the amount of suspended solids and reduce the <br />possibility of flood hazards by retaining runoff during storm events. <br />With regard to groundwater, CAM provided a PHC analysis for the alluvial <br />groundwater only. Bedrock groundwater will not be affected by the loadout <br />operations. Alluvial groundwater in the permit area occurs in river alluvium that <br />lies over Mancos shale. It is unlikely that the groundwater beneath the proposed <br />loadout facility is directly related to the Colorado River. It is possible that <br />groundwater beneath the property may, in part be the result of irrigation in the <br />upland areas, using water from up river diversions. The water quality of the <br />alluvial groundwater is relatively poor and is predominantly a calcium - sodium <br />sulfate water with elevated iron and manganese. Total dissolved solids range from <br />5,800 to 8,800 mg/L and there are no domestic or irrigation wells located <br />immediately downgradient of the permit and adjacent areas. Soils at the surface <br />are described as silty -clay with low permeability. <br />CAM analyzed infiltration from surface water runoff to shallow alluvial <br />groundwater. CAM concluded that in clayey soils percolation is slow and most <br />water is held at shallow depths, where it can be lost to evapotranspiration. Intense <br />precipitation produces surface runoff and low percolation. This combined with the <br />semi -arid climate of the Grand Valley with very high evapotranspiration rates, <br />runoff from the loadout should not impact alluvial groundwater as most water will <br />be lost to evapotranspiration before it can infiltrate the alluvial groundwater. <br />Further, CAM is required by the USFWS conservation measures to line the three <br />sediment ponds. This will effectively prevent seepage of water and dissolved <br />constituents and mobilization of contaminants in pond substrates. Water from the <br />sediment ponds will not leach into the shallow alluvial groundwater. According to <br />pond operations discussed in Section 2.05.3(4)(a)(ii)(C), the pond(s) will be <br />dewatered within 48 hours of a precipitation event and any time the water exceeds <br />the maximum sediment elevation. Sediment and water removed from the ponds <br />will be disposed of at an approved disposal facility. CAM concludes that the <br />loadout facility operation does not have the potential to negatively impact <br />groundwater quality in the shallow alluvium. <br />IV. Topsoil <br />Baseline soils information is found in Exhibit 7 in Volume 1 of the PAP. A discussion <br />of the potential productivity of the soils was obtained from the NRCS Soil Survey of <br />Grand Junction Area, Colorado and included in Section 2.04.9 of the PAP. <br />All available topsoil will be salvaged from the areas to be disturbed after vegetation <br />cover that would interfere with the use of the topsoil is cleared. Sagebrush, forbs and <br />grasses will not be cleared prior to topsoil salvage. Tamarisk will be cleared from areas <br />28 <br />