2010-05-07_GENERAL DOCUMENTS - C2009087

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few tens of feet per year in a basinward direction. Faults may provide vertical conduits of ground water flow wherever a fault is not sealed with fine-grained gouge material. The alluvium of Grassy Creek and Fish Creek, and their tributaries, is either directly recharged by stream flow or discharges to stream flow, depending on stream flow level. The alluvial aquifers probably contribute to stream baseflows during dry periods. Ground water flow velocity in alluvium probably is on the order of a few feet per day in a downstream direction Natural Springs The permit application contains information on natural springs in Section 2.04.7, Map 2.04.7 M2, and Table 2.04.7-T7.2. In addition to the spoil spring monitoring described below, SCCC performed an inventory of natural springs and seeps within and adjacent to the PSCM permit boundary in August 2009. Ground water flows to the land surface via springs at several locations outside the southwestern boundary of the permit area. Nine springs were sampled during the inventory. Seven springs in the area have adjudicated water rights. Flows sampled were less than 5 gallons per minute. Total dissolved solids were in the 430 to 2,920 mg/l range. The water is a calcium- magnesium bicarbonate or sulfate type. The probable sources of the springs are the intergranular porosity or fracture porosity in bedrock formations. The springs and seeps discharge wherever the potentiometric surface intersects the land surface, either from an outcrop or a fracture or fault, or from alluvium or colluvium that covers the bedrock. Surface Water Surface water hydrology information can be found in Section 2.04.5 of the permit application. The information includes baseline data collected in 2008 and 2009. Of the approximate 10,164 acres in the PSCM permit area, 9,361 acres are in the Grassy Creek drainage basin and 803 acres are in the Fish Creek drainage basin. Grassy Creek and Fish Creek are perennial streams that are tributaries of the Yampa River. Grassy Creek has intermittent or ephemeral tributaries in the PSCM permit area that include Little Grassy Creek, Annand Draw, and Scotchman's Gulch. Fish Creek has an intermittent tributary in the PSCM permit area known as Cow Camp Creek. Grassy Creek flows into the Yampa River approximately two miles north of the PSCM permit boundary. Fish Creek flows into Trout Creek approximately six miles east of the PSCM permit boundary. Trout Creek flows into the Yampa River approximately five miles north of the Fish Creek/Trout Creek confluence. The Yampa River drains much of northwestern Colorado and joins the Green River, which flows to the Colorado River. All stream waters in the vicinity of the PSCM usually carry a large load of natural suspended solids during periods of runoff from snowmelt or rain. Little Grassy Creek drains an area on the western flank of the Tow Creek: anticline which includes most of the Seneca II Mine lands proposed for transfer to the PSCM and the areas proposed to be disturbed by PSCM underground mining activities. Upstream from mine disturbances, flow in Little Grassy Creek commonly peaks in May or June at less than 2.5 cfs and then diminishes to zero by mid-summer. Water in Grassy Creek is primarily a calcium-sodium bicarbonate type. Total dissolved solids (TDS) generally are in the range of 1,000 to 2,000 mg/l. Spoil spring inflow from Pond 002, one of three existing Seneca II sedimentation ponds that will be transferred to the PSCM, commonly increases the flow in Little Grassy Creek to 5 cfs and increases TDS to between 3,000 and Peabody Sage Creek Mine 7 May 7, 2010