Laserfiche WebLink
Water-Iwel elevations fnr the Johnson Gulch aliwial well J-1 are also pn:sented in <br />Fgure A-15. The J-1 water levels remained steady in 2003. <br />2.2 GROUND WATER-LEVEL ELEVATION (PIEZOMETRIC MAP SUMMARI~ <br />Hydro-Engineering developed three piezometric maps to show the water level <br />flow patterns for the QR, HI and 3rd White Sandstone aquifers at Trapper Mine. Water <br />levels from the Fall of 2003 were used to develop these maps. <br />Map No. 2-1 preserts the water-level elevations for the QR aquifer. The <br />water-level elevation is pn~ented for the QR wells: GD-2, GE-1, GFti, GP-5, and GP-6 and <br />backfiil wells GD-3 and GFll. The ground-water flow in the QR aquifer is mainly th the <br />north. Mining has only affected the QR aquifer close to the D, E, F and G pits by causing <br />drawdowns very near the pit edges. The installation of backfill wells GD-3 and GFll has <br />defined the depressed elevations in the bacldifl areas. The welts in this area experienced <br />fairly steady to gradual declining levels during 2003. The gradual declines and steady levels <br />are likely due to less recharge in the last sbc years. The backfill water levels will likely <br />stabilize lower than the pre-mine levels due to the increased permeability of the badcfill <br />aquifer, which allows the water in the aquifer to be transmitted at a lower gradient. The <br />gradient calculated for the baddill near D pit is 0.008 ft/ft, compared to the undisturbed <br />gradient of 0.14 ft/ft near well GP-6. The heads in the northern end of the bacldiil aquifer <br />will likely recover above the pre-mine level. Backfill springs are not expected to develop <br />near the northern end of the QR badd911 because backfill water levels would have to recover <br />greater than a few tens of feet to reach the lower land surface elevations. Table 2-1 of the <br />1990 Annual Hydrologic Report (Hydro-Engineering, 1991) presents aquifer properties at <br />2-9 <br />