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outcrops at approximately the location and elevation of the South Portals and dips at approximately <br /> 3 degrees beneath the river to the northeast. The seam mined at the North Portals is below the <br /> elevation of the river, but "cross dip" from the river. The entire sequence of Mesaverde that <br /> overlies the Cameo coal zone, behaves as a single hydrologic unit. <br /> The water table in the permit area and adjacent area can be directly correlated to its elevation <br /> relative to the Colorado River. Rock formations and alluvium below the level of the river are <br /> gravity-fed and are saturated with water from the river. Due to the clastic differentiation and <br /> lensing of sandstones and shales in the area together with the low permeability of the rock, the <br /> strata above the zone of saturation act to confine the body of groundwater. Therefore, the water <br /> table is located at approximately the same elevation as the Colorado River. <br /> This fact is important in defining the hydrologic impact on the water-bearing strata by the mine <br /> operation (see the Probable Hydrologic Consequences section of this document). There are four <br /> primary water bearing zones that may be directly or indirectly affected by the mine operation: the <br /> Colorado River alluvium, the undifferentiated sandstone lenses in the Mesaverde above the coal <br /> seam, the Cameo coal seam, and the Rollins sandstone unit below the coal seam. <br /> There are no aquifers in the permit or adjacent area that can store and transmit water of sufficient <br /> quality or quantity for beneficial use. A September, 1997, study included in the permit application <br /> package confirms that the Rollins Sandstone in the permit area does not meet the regulatory criteria <br /> of an aquifer. Laboratory analyses have shown groundwater in the permit vicinity to be high in <br /> salts and of poor quality. Therefore, no beneficial uses of groundwater exist in the permit or <br /> adjacent area. No groundwater rights have been adjudicated on or adjacent to the permit area to <br /> date. Only one groundwater well (an alluvial well) exists adjacent to the permit area; it is used for <br /> stock watering. <br /> Additional information on hydrology can be found in Tabs 7, 17 and 18, of the permit application <br /> package. <br /> Surface Water Hydrology <br /> A general description of the surface water hydrology of the permit area is found in Volume 2, Tab <br /> 7 of the permit application. Maps displaying the general surface water hydrology are found in <br /> Exhibits 1 and 17 of that document. Please see Section B.II of this document for a discussion of <br /> the Probable Hydrologic Consequences (PHC) of the Roadside Portal Mines on surface water <br /> quantity and quality and for a further discussion of the surface water monitoring plan. Alluvial <br /> valley floors (AVF's) are discussed in Section B.XIII of this document. <br /> The Colorado River is the only perennial stream in the permit area. On the west side of the river, <br /> Coal Creek and Jerry Creek flow through the Roadside North Portal portion of the permit area <br /> within deeply incised canyons draining approximately 12 and 70 square miles, respectively. Coal <br /> Creek, an ephemeral drainage, passes through surface mine disturbance near the Roadside North <br /> Portal where the channel has been diverted. Jerry Creek is an intermittent drainage located in the <br /> extreme northern portion of the permit area. Flows in all of these drainages occur primarily during <br /> spring snowmelt and in response to sudden, high intensity thunderstorms, the latter of which are <br /> 9 <br />