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3.1 WATER LEVELS <br /> The static water levels measured during the 2020 water year are included with the <br /> groundwater quality data in Appendix B. Water level hydrographs for each of the <br /> wells are also provided in Appendix C. The static water level was measured at all <br /> wells except for WSC25, where the well casing was damaged and a measurement <br /> could not be made. The water levels measured at all wells this year were within their <br /> respective historic range. Water levels in most of the water bearing units at SIIW <br /> exhibit seasonal fluctuations. The water table in the shallow alluvial wells fluctuates <br /> in response to seasonal precipitation events, with the water table typically at its <br /> highest during the spring snowmelt seasons and then declining through late <br /> summer/early fall in response to the dry conditions. The water levels in the bedrock <br /> overburden and coal seams also fluctuate in response to recharge from seasonal <br /> precipitation but are partially influenced by interactions with groundwater in the <br /> reclaimed mine spoil. <br /> 3.2 GROUNDWATER QUALITY <br /> Monitoring well DCAL-02 serves as the Groundwater Point of Compliance (GWPOC) for <br /> SIIW (see Technical Revision 63). This well is screened within the Dry Creek Alluvium <br /> and is located downgradient of the mines permit boundary. Only a small portion of <br /> the SIIW mining area was located within the Sage Creek Watershed and a GWPOC for <br /> the Sage Creek Alluvium was deemed unnecessary because the spoil ground water in <br /> this area flows to the west along the dipping bedrock, away from the Sage Creek <br /> tributaries. GWPOC bedrock wells were also deemed unnecessary because of the <br /> limited potential for the mine to negatively impact the quality of bedrock <br /> groundwater. The low hydraulic conductivity of the bedrock units inhibits <br /> groundwater from migrating away from the mine and low permeable confining layers <br /> further isolates groundwater at the mine from the nearest aquifer, the Trout Creek <br /> Sandstone. Bedrock groundwater has not historically been used in this area because <br /> its undisturbed, ambient, quality is marginal to unsuitable for both livestock and <br /> irrigation purposes and the yields are low. <br /> Page 7 of 17 <br />