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and lenticular'sandstonesarad coals and within isolated alluvial aquifers. Base flow in the two <br />perennial streams in the general area comes mainly from ground water discharge from alluvial <br />aquifers in the stream valleys. Stratigraphically, the Trout Creek Sandstone is the major regional <br />aquifer in the area. 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 azea <br />above the flood plain of Goodspring Creek. No saturation was encountered in any of the beds to <br />be trained in test holes drilled by W.R. Grace and Company and the USGS (information contained <br />in the Permit and the Northwest Colorado EIS). <br />The Trout Creek Sandstotn; outcrops north of the permit azea, where ground water is discharged <br />at flee surface. The Manco:> Shale underlies the Des 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 -es <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 pemut azea is drained by two perennial streams; Goodspring <br />Creek to the east and Wils~~n 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 />the Streeter Canyon, the deepest fill (the Streeter Fill) near the confluence of Streeter Drainage <br />and Goodspring Creek. These drainages are tributaries to Milk Creek, which flows into the <br />Yampa River which is loctaed about seven miles north of the permit azea. Precipitation averages <br />18 inches annually on the property and runoff is limited. Flows in the drainages are mainly in <br />14 <br />