2003-08-26_GENERAL DOCUMENTS - C1981041

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single hydrologic unit. The water table in the permit area and adjacent area can be directly correlated to its elevation relative to the Colorado River. Rock formations and alluvium below the level of the river aze gravity-fed and aze saturated with water from the river. Due to the clastic differentiation and lensing of sandstones and shales in the area together with the low permeability of the rock, the strata above the zone of saturation act to confine the body of groundwater. Therefore, the water table is located at approximately the same elevation as the Colorado River. This fact is important in defining the hydrologic impact on the water-bearing strata by the mine operation (see the Probable Hydrologic Consequences section of this document, Section C.II.). There aze four primary water bearing zones that may be directly or indirectly affected by the mine operation: the Colorado River alluvium, the undifferentiated sandstone lenses in the Mesaverde above the coal seam, the Cameo coal seam, and the Rollins sandstone unit below the coal seam. There aze no aquifers in the permit or adjacent azea that can store and transmit water of sufficient quality or quantity for beneficial use. A September, 1997, study included in the permit application package confimrs that the Rollins Sandstone in the permit azea does not meet the regulatory criteria of an aquifer. Laboratory analyses have shown groundwater in the permit vicinity to be high in salts and of poor quality. Therefore, no beneficial uses of groundwater exist in the permit or adjacent azea. No groundwater rights have been adjudicated on or adjacent to the permit azea to date. Only one groundwater well (an alluvial well) exists adjacent to the permit azea; it is used for stock watering. Piease refer to Section C.ILI. (Probable Hydrologic Consequences) for further hydrologic information, including the groundwater monitoring plan. Additional information on hydrology can be found in Tabs 7, 17 and 18, of the permit and Section C.II. of this document. Surface Water Hydrology A general description of the surface water hydrology of the permit azea is found in Volume 2, Tab 7 of the permit application. Maps displaying the general surface water hydrology are found in Exhibits 1 and 17 ofthat document. Please see Section C.II. of this document for a discussion of the Probable Hydrologic Consequences (PHC) of the Roadside Portal Mines on surface water quantity and quality and for a further discussion of the surface water monitoring plan. Alluvial valley floors (AVF's) are discussed in Section C.XI. of this document. The Colorado River is the only perennial stream in the permit azea. On the west side of the river, Coa] Creek and Jetry Creek flow through the Roadside North Portal portion of the permit azea within deeply incised canyons draining approximately 12 and 70 squaze miles, respectively. Coal Creek, an ephemeral drainage, passes through surface mine disturbance neaz the Roadside North Portal where the channel has been diverted. Jerry Creek is an intermittent drainage located in the extreme northern portion of the permit area. In addition, a small portion of the permit azea drains to Asbury Creek, which enters the Colorado River from the northwest, to the east of Jerry Creek. Flows in all of these drainages occur primarily during spring snowmelt and in response to sudden, high intensity thunderstorms, the latter ofwhich are characterized by high peak dischazges, short flow durations and high sediment loads. On the east side of the river, the Roadside Mine will undermine two additional canyons: Rapid Creek and Cottonwood Creek. Both creeks aze intermittent during most years, but do flow continuously during wet yeazs. Flows in these creeks occur primarily in response to annual snowmelt and seasonal precipitation events. Intake stmctures aze present in both Rapid Creek and Cottonwood Creek to divert water from those drainages 12