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During mining, sediment ponds would reduce the amount of surface flow in Bolton Draw by approximately 17% (p. 7800126eeeee). Changes in surface water chemistry would also occur to the extent that ephemeral stream flow recharges the alluvial aquifer and the quantity and quality of the water available for sub-irrigation would be affected. As discussed in the statement of probable hydrologic consequences, these effects would be short termed. With reclamation and removal of the sedunent control system, these effects would be mitigated. Most of the mining that would occur in the Bolton Draw watershed has already occurred under the previously permitted operations: 3. Surface coal mining and reclamation operations would be conducted to preserve, throughout the mining and reclamation process, the essential hydrologic functions of the alluvial valley floor. Mining operations would not physically disturb the alluvial valley floor. With successful reclamation and removal of the sediment control system the surface water flow to the draw would be restored and water chemistry would return to natural conditions. The applicant has suggested that the release of sediment deficient waters from the sediment ponds would cause downstream erosion (780-124). Should this occur, the erosion would begin immediately downstream from the sediment ponds on unnamed tributaries to Bolton Draw. Given the infrequent nature of streamllow in this area, erosion would be observed and could be mitigated before it could spread to Bolton Draw, and cause channel incision in the Alluvial Valley Floor. Alluvial Valley Floors -Sudduth Draw -Findings 1. The proposed surface coal mining operation would not interrupt, discontinue, or preclude farming on an alluvial valley floor. None of the proposed mining operations would be located within the alluvial valley floor. The final mining activities in Pit 3 would be located immediately adjacent to the alluvial valley floor. A buffer would be left along Sudduth Draw, according to Map 15a no mining activities would encroach upon the AVF. 2. The proposed operations would not materially damage the quantity and quality of water in surface and subsurface water systems that supply those alluvial valley floors or portions of alluvial valley floors. Mining in the Sudduth Draw watershed would affect the quantity and quality of surface water supplied to the alluvial valley floor as described in the applicant's statement of probable hydrologic consequences (p. 780-123 to 780-126jjjjj). Mining would reduce Marr Strip Mine, C-80-006 28 December 9, 1992