2018-01-31_REVISION - C2009087 (30)

Home Browse Search

is an alkaline calcium magnesium sulfate water with TDS that ranges between 300 and 4,000 mg/l range. Spoil leachate is an alkaline calcium -magnesium sulfate type water, with total dissolved solids in the 2,600 to 4,300 mg/1 range. Bedrock hydrostratigraphic units in the vicinity of the PSCM permit area are likely recharged by meteoric waters wherever a significant quantity of snowmelt or rainfall accumulates on bedrock outcrops at high elevations around the perimeter of the Hayden Syncline. The water seeps into the rock through intergranular porosity and fractures. Immediately down dip from a recharge area, the bedrock is under water table conditions. From a recharge area, bedrock groundwater flows under the force of gravity generally down dip, toward the deeper part of the Sand Wash Basin (or Twentymile Park east of the permit area) where the ground water is under confined conditions. The head (hydraulic pressure) at a location in a basin is determined by the height of the recharge areas above that location and the proximity to discharge areas. Bedrock units discharge ground water at low elevations in a basin wherever the units crop out or have a subcrop underneath the younger colluvium and alluvium. The dissolved solids content of ground water in bedrock units generally increases basinward from the recharge areas. The potentiometric surface of ground water in the confined portions of the bedrock units slopes generally basinward. Local relief on the potentiometric surface probably mimics the overlying topography, with potentiometric highs and lows roughly coinciding with the overlying highs and lows of the land surface. 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 baseflow during dry periods. 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 spoil springs, an inventory of natural springs and seeps within and adjacent to the PSCM permit boundary sampled 9 springs, 7 of which have adjudicated water rights. Flows sampled were less than 5 gallons per minute and TDS ranged from 430 to 2920 mg/l range. 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 approximately 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, 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 approximately five miles north of the Fish Creek/ Trout Creek confluence. 7