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winter/spring and lows in late summer/fall An overall gradual decline in water levels occurred the last <br />few years. Well P-3 is completed in the Lewis Shale outcrop, which is in contact with the Pyeatt <br />alluvium It demonstrates the same seasonal variations (Figure A-13) as the alluvial P-1 well <br />Water-level elevations for the Johnson Gulch alluvial well J-I are also presented in Figure <br />A-13. The J-1 water levels remained steady in 2004. <br />2.2 GROUND WATER-LEVEL ELEVATION (PIEZOMETRIC MAP SUMMARY) <br />Hydro-Engineering developed three piezometric maps to show the water level flow patterns <br />for the QR, HI and 3rd White Sandstone aquifers at Trapper Mine. Water levels from the Fall of 2004 <br />were used to develop these maps. <br />Map No. 2-1 presents the water-level elevations for the QR aquifer. The water-level <br />elevation is presented for the QR wells: GD-2, GE-1, GF-ti, GP-5, and GP-6 and backSll wells GD-3 <br />and GF-11. The ground-water flow in the QR aquifer is mainly to the north Mining has only affected • <br />the QR aquifer close to the D, E, F, G and Z pits by causing drawdowns very near the pit edges. The <br />installation of backfill wells GD-3 and GF-11 has defined the depressed elevations in the backSll areas. <br />The wells in this area experienced fairly steady levels during 2004. The gradual declines and steady <br />levels are h7cely due to less rechazge in the last seven years. The bacldill water levels will hkely stabilize <br />lower than the pre-mine levels due to the increased permeability of the backfitl aquifer, which allows <br />the water in the aquifer to be transmitted at a lower gradient. The gradient calculated for the bacldill <br />neaz D pit is 0.005 ft/ft, compared to the undisturbed gradient of 0.12 ft/ft near well GP-6. The heads <br />in the northem end of the backfill aquifer will likely recover above the pre-mine level Backfill springs <br />aze not expected to develop near the northern end of the QR backfill because backfill water levels <br />would have to recover greater than a few tens of feet to reach the lower land surface elevations. Table <br />2-1 of the 1990 Annual Hydrologic Report (Hydro-Engineering, 1991) presents aquifer properties at <br />Trapper Mining Company 2-8 <br />2004 Annual Report <br />