2011-01-13_REVISION - C1980006 (9)

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2. The proposed operations will not materially damage the quantity and quality of water in surface and groundwater systems that supply those alluvial valley floors or portions of alluvial valley floors. The surface waters that supply the 55-acre flood-irrigated pasture are originally derived from the Michigan River. As described in the probable hydrologic consequences (pages 780-123 to 780-1 26jjjjj), the river is not significantly affected. While active, sediment ponds were expected to reduce the amount of surface flow in Bolton Draw by approximately 17 percent (page 780-1 26eeeee). Changes in surface water chemistry were expected to 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 were expected to be affected. As discussed in the applicant's statement of probable hydrologic consequences, these effects were expected to be short term. With reclamation and removal of the sediment control system, these effects were expected to be mitigated. Most of the mining approved to occur in the Bolton Draw watershed has already occurred under the previously permitted operations. 3. Surface coal mining and reclamation operations are expected to be conducted to preserve, throughout the mining and reclamation process, the essential hydrologic functions of the alluvial valley floor. Mining operations will not physically disturb the alluvial valley floor. With successful reclamation and removal of the sediment control system, the surface water flow to the draw is expected to be restored and water chemistry expected to 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 streamflow in this area, erosion is expected to be observed and 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 will not interrupt, discontinue, or preclude farming on an alluvial valley floor. None of the proposed mining operations will be located within the alluvial valley floor. Final mining activities in Pit 3 were to be located immediately adjacent to the alluvial valley floor. A buffer was to be left along Sudduth Draw, according to Map 15a. No mining activities were expected to encroach upon the alluvial valley floor. 27