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2.1 GxOQND WATER-LEVEL CHANGES <br />2.1.1 SIJlQlAEY <br /> <br />Significant mine activities during 1993 include the closure of <br />the B and C pit areas,the opening of H pit in late August, the <br />expansion of A pit in the East Pyeatt area, the start-up of a <br />second operational ash disposal site in A pit (Middle Pyeatt <br />drainage area), and a decrease in dewatering Nell pumpage in D pit. <br />Annual precipitation for 1993 was 18.71 inches, up from 16.71 <br />inches in 1992 and above average precipitation. This recent <br />increasing trend began in 1991 but is still below the high of 25 <br />inches observed in 1983 (Figure 2-1). Recharge in this geographic <br />setting is directly related to precipitation. <br />The effects of natural recharge variations on the respective <br />aquifers can be observed in wells located in undisturbed areas away • <br />from the influence of mining activities. Well GC3 exhibited the <br />alluvial water level response with a spring and summer increase due <br />to recharge and a fall decline. The net September, 1992 through <br />August, 1993 change was +7.5 ft. The effects on the 3rd White <br />aquifer are observed in wells GC2 and GP9. Both wells show a <br />general decline since 1987 with subdued seasonal variations <br />becoming more stable. The September, 1992 through August, 1993 <br />changes are +1.41 ft. (GC2) and -0.4 ft. (GP9). The HI aquifer <br />(GC1, GP7) is characterized by a flat water level trend with <br />variations over a one foot range. The September, 1992 through <br />August, 1993 changes are +0.75 ft. and +Q},9 ft., respectively. The <br />KLM aquifer (GP2, GP8) has shown a declining trend, stabilizing in <br />Z-2 <br />L_J <br />