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<br /> <br /> <br /> <br /> <br />t <br />3.2 Comparison of Projected Impacts With Observed Impacts <br />The comparisons of the projected impacts (probable hydrologic consequences) with the <br />observed impacts are discussed in the following. <br />The water withdrawal rate from the lagoon in the White River Alluvium this reporting year <br />(October 1, 1998 to September 30, 1999) was estimated at 130,044,008 gallons or 399.1 <br />acre-feet. This compares with an expected withdrawal rate of 552 acre-feet per year at full <br />production. <br />' The decline in piezometric levels in bedrock zones "upper sandstone facies", "siltstone/coal <br />facies", and "lower sandstone facies" was anticipated as probable impacts as the result of <br />' underground mining activities. As projected these impacts are localized and will most probably <br />continue in the proximity of the mined area. <br />' As projected, subsidence in Red Wash initially resulted in water ponding in the stream bottom. <br />The high content of silt and clay carried by Red Wash rapidly fills the ponds. The silt and clay <br />' layers have sealed any cracks that formed in the alluvium as the result of subsidence. Water <br />continues to flow in the surface channel at Red Wash indicating that the basal alluvium is not <br />recharged by surface flow infiltration. <br />' 3.3 Significance of Impacts to Use of Water <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br />The current rate of withdrawal of water from the lagoon in the White River alluvium is far below <br />that projected at full production. Based on the current level of production and the current rate of <br />withdrawal, BME is not likely to exceed the projected withdrawal rates even at higher production <br />levels. <br />During this reporting period, significant changes in piezometric levels were noted for the <br />"middle sandstone/coal facies" at TW2-17M (a decrease of 39.7 feet) and the lower sandstone <br />facies at 4-20L (a decrease of 10.9 feet). <br />Water ponding in Red Wash as the result of subsidence over longwall panels No. 1, No. 2, No. <br />3, No. 4, No. 5, 6 and No. 7 acted as stilling basins for deposition of clays and silts being carried <br />down Red Wash. The significance of this impact is beneficial as the sediment load to the White <br />River was reduced. The same impact is expected as a result of subsidence over subsequent <br />longwall panels. <br />17 <br />t <br />