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2. The proposed operations will not materially damage the quantity and quality of water in <br />surface and subsurface water systems that supply those alluvial valley floors or portions <br />of alluvial valley floors. <br />Mining in the Sudduth Draw watershed was previously expected to affect the quantity <br />and quality of surface water supplied to the alluvial valley floor as described in the <br />applicant's statement of probable hydrologic consequences (pages 780-123 to 780- <br />126jjjjj). Mining was expected to reduce surface flow in Sudduth Draw by <br />approximately three percent of the annual yield. It was previously anticipated that the ion <br />balance of the surface water could be altered, and salt loading on the stream could be <br />increased by 2.7 kilograms per year. These changes were not expected to represent a <br />significant change in surface water quantity or quality. As discussed in the summary of <br />probable hydrologic consequences, the effects were expected to be temporary and <br />mitigated by reclamation. <br />3. Surface coal mining and reclamation operations will be conducted to preserve, <br />throughout the mining and reclamation process, the essential hydrologic functions of the <br />alluvial valley floor. <br />Mining operations did not physically disturb the alluvial valley floor. Minor changes in <br />surface water supplied to the alluvial valley floor (as discussed above) occured during the <br />mining phase of the operation. With successful reclamation and removal of the sediment <br />control system, the quantity and quality of surface flow supplied to the alluvial valley <br />floor are expected to return to natural conditions. <br />The applicant has suggested that the release of sediment-deficient waters from the <br />sediment ponds could cause downstream erosion. Should this occur, the erosion is <br />expected to begin immediately downstream from the sediment pond on Sudduth Draw. <br />Given the infrequent nature of runoff in this area, this erosion, as it occurs, should not be <br />so severe as to affect the essential hydrologic functions of Sudduth Draw. <br />4. The alluvium of Sudduth Draw is recharged during snowmelt and precipitation events <br />when this intermittent stream is flowing. The stock ponds located along Sudduth Draw <br />provide sufficient detention time to increase recharge and to sustain sub-irrigation for <br />longer periods of time. <br />There is a spring tributary to Sudduth Draw in the Old Sudduth Mine, located in Section <br />15, T9N, R78W. Upon examining color infrared aerial photos of the northern portion of <br />Pit 3, it was determined that this spring does not provide significant water to Sudduth <br />Draw. Kerr Coal Company has also determined that this spring increases salt loading in <br />Sudduth Draw (page 780-126a). Should mining occur in Pit 3, this spring will be <br />destroyed. This will not significantly affect the flows in Sudduth Draw. <br />Should mining of Pit 3 occur, it will impact the quantity of water flowing in Sudduth <br />Draw and sub-irrigation in its valley in the pit's northernmost extent. Water will infiltrate <br />28