Laserfiche WebLink
possible. The locations of these discharges are shown on Map 37, Fish Creek Groundwater Inflow Survey. Selected <br />• locations were measured for flow, temperature, specific conductance, % salinity, and pH. The field data collected <br />during the survey is shown on Table 60, Fish Creek Stream and Inflow Investigation. Flows were measured using a <br />portable 4-inch cutthroat flume or a bucket and stopwatch. Field water quality was measured using standard <br />instrumentation. <br />The only significant spring identified during the survey issues from the Tweirtymile sandstone in Section 11, TSN, <br />R86W.~This spring will be monitored as part of the overall Hydrologic Monitoring program (Exhibit 14). <br />As described above, two springs occur within the north half of section 36, TSN, R87W. The existing monitoring data <br />indicates the springs ate low producers, typically discharging at a rate of 5 gpm or less. The springs appear to issue <br />from the Fish Creek Sandstone. These two springs were added to Twentymile Coal Company's hydrologic monitoring <br />plan and will be monitored on a quarterly basis for quantity and quality. Exhibit 14 has been modified to include these <br />springs. <br />(b) The application shall contain additional infonna[ion, which describes the recharge, storage, and discharge <br />characteristics ofaquifers and the quality and quantity of ground water far the proposed permit and adjacent <br />areas, according to the parameters and in the detail required b}' the Division. The application shall also <br />provide well locations and reported yields from all wells withut the proposed permit and adjacent areas, <br />which are registered with the Office of the State Engineer. <br />Twentymile Park, which includes the proposed permit and adjacent areas, lies within asemi-arid climatic zone with an <br />average annual precipitation of only 16 inches. With the exception of the spring snowmelt, which results primarily in <br />surface runoff, most of the precipitation received is lost through evapotranspiration and sublimation. As a result, the <br />• amount of precipitation available for ground water recharge is limited. <br />All ground water aquifers in the general area, except the alluvial aquifers, are recharged by infiltration in outcrop <br />areas. Outcrop areas for the principal ground water aquifers are shown on the Twentymile Sandstone Potentiometric <br />Surface Map (Map 33). <br />Bedrock Aouifers <br />The configuration of the potentiometric surface for the Wadge overburden aquifer (Map 13, Twentymile Park <br />Hydrology) indicates the direction of ground water movement in this unit. Ground water movement is generally <br />oriented perpendicular to the potentiometric contours in the d'vection of decreasing potentiometric elevation. The map <br />indicates that Bound water tends to move from the recharge areas at the outcrops of these units near the southern and <br />western margins of Twentymile Park Basin towazd the center of the basin, reflecting the sdvctural dip of the lithologic <br />units. The general trend of movement in the permit area is to the north and northwest. Discharge from the Wadge <br />overburden to alluvial aquifers and surface streams is believed to occur in the vicinity of the outcrop area in the <br />eastern and northeastern margins of the basin. A major fault zone in this area may be a significant conduit for much <br />of this discharge. <br />Ongoing monitoring and a series of pump tests conducted by various government agencies and independent <br />consultants have delineated characteristics of the Wadge Overburden in the permit and adjacent areas. The pump tests <br />were conducted under a broad range of conditions and varied in duration from 30 minutes to 72 hours. The <br />characteristics of specific intervals within the Wadge Overburden were tested utilizing temporary well packers and <br />monitoring variations in water levels and flows in adjacent observation wells with continuous water level and <br />discharge recorders. <br />• Characteristics of the Wadge Overburden determined for specific monitoring wells in the permit and adjacent area are <br />summarized in Exhibit 9, Aquifer Test Data. The highest permeability values for the Wadge Overburden (0.3 and o.6 <br />tt/day) are calculated from observation well date (wells 006-82-74A and 74C), and may reflect effects of using radial <br />Permit RenewalNo.3 2.04-25 APPROVED APR 2 4 Z~~ttni99 <br />