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3.2.8 Ground Water Hydrology <br />Ground water information is found in Sections 2.04.5, 2.04.7 and Exhibit 7 of the Permit and <br />Annual Hydrologic Reports. Ground water occurs as isolated, perched aquifers in interbedded <br />and lenticular sandstones and coals and within isolated alluvial aquifers. Base flow in the two <br />perennial streams in the general area comes mainly from ground water dischazge from alluvial <br />aquifers in the stream valleys. Stratigraphically, the Trout Creek Sandstone is the major regional <br />aquifer in the azea. It is approximately 800 feet beneath the lowest coal seam to be mined. The <br />principal recharge for the aquifer is to the south of the permit azea in the headwaters of Taylor <br />and Goodspring Creeks. There is no continuous, regional ground water system on the permit <br />azea above the flood plain of Goodspring Creek. No saturation was encountered in any of the <br />beds to be mined in test holes drilled by W.R. Grace and Company and the USGS (information <br />contained in the Permit and the Northwest Colorado EIS). <br />The Trout Creek Sandstone outcrops north of the permit azea, where ground water is discharged <br />at the surface. The Mancos Shale underlies the Iles Formation and forms the base of the regional <br />ground water system in the area. This shale is exposed at the surface north of the permit area, in <br />the southern limb of the Axial Basin Anticline. Due to the impervious nature of the Mancos <br />Shale, ground water flow in either the deep bedrock units of the Williams Fork and Iles <br />Formations, or in the alluvial aquifers of Goodspring and Wilson Creeks, is discharged to the <br />streams where they flow across the Mancos Shale. <br />3.2.9 Surface Water Hydrology <br />Surface water information is found in Sections 2.04.7 and 4.05; Maps 11, 12, 12A, 32 and 37; <br />and Exhibit 7 of the Permit. The permit area is drained by two perennial streams; Goodspring <br />Creek to the east and Wilson Creek to the west. Taylor Creek, an intermittent. stream, flows into <br />Wilson Creek north of the rail loadout. Several ephemeral drainages occur on the permit azea, <br />including the Streeter Drainage. This drainage profile was raised as a result of excess spoil fill in <br />18 Revised October 30, 1997 <br />