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Probable Hydrologic Consequences-Groundeater The eater table in the permit area and adjacent area Correlates directly co the elevation of the Colorado River. Rock formations and alluvium below the level of the river are recharged by the Colorado River and have piezometric levels equal to that of the rivet at the recharge zone. Three stratigraphic units may be defined as aquifers and each transmits water to or is recharged by, the river. The first unit is the strata overiyi~ the coal seam. This unit consists of interbedded sandstones and shales of dis- continuous lateral extent. The stratigraphy of this unit indicates that the strata overlying the coal zone behaves as a single hydraulic unit containing localized perched aquifers recharged by the river in some areas. Ground eater move slowly through and between interconnected sandstone and shale leases and beds. The second unit is the Cameo coal seam. The coal seam receives recharge eater from the river where the seam dips below the river at an elevation of 4750 feet within the Cameo Hine. The 114 feet thick Rollins Sandstone formation is the thickest and most continuous sandstone in the project area. The Rollins Sandstone is the third eater-bearing unit and constitutes the best potential aquifer in the region. The Rollins Sandstone underlies the entire permit area, except within De beaus Canyon, where it outcrops. Recharge to the Rollins Sandstone occurs primarily is the subcrops below the alluvium of the •, Colorado River. Ia addition to the above, the alluvial deposits of the Colorado River flood plain may also be classified as an aquifer. The alluvium contains eater from the river and recharges eater to permeable units beneath it. The strata in the Roadside `Sine plan area dips towards the Colorado River, whereas the strata is the Cameo mine plan area dips away from the Colorado River. The ground eater from the Roadside mine plan area located strati- graphically higher than the Colorado River will discharge into the Colorado River, whereas the Colorado River will recharge the strata located strati- graphically lover than the Colorado River system in the Cameo Mine plan axe a. The company will have to submit evidence that adequate water rights have been secured to replace the valet that is lost from the Colorado River prior to mine closure. The major effect of mining on the quality of eater is an increase in the sol- uble saltwater levels. The mine discharge eater has roughly a 3-4 fold higher content of soluble salts than the Colorado River. These discharges are di- luted by receiving eaters, resulting in a total Increase in the soluble salt level of the river by O.1S the underground disposal of coal processing waste at the Roadside mine should have an insignificant effect on ground eater quality, since it is similar in nature to the material presently exposed in the xiae. The water used to transport the waste material into the abandoned underground vork'_ags -.rill be drained and reused, and except for loss, this eater should have an insignificant effect '_n around eater. -~-