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RESPONSE <br />The Fish Creek floodplain within the proposed permit area appears to meet the geomorphic criteria of an AVF. <br />• For portions of Fish Creek, however, applicability of hydrologic and agricultural significance criteria has never <br />been conclusively determined. The following discussion of mining -related impacts on the Fish Creek AVF is <br />based not on applicability of regulatory AVF criteria to Fish Creek in its entirety, but rather on agency <br />designations as previously discussed. <br />Mining operations are not expected to significantly affect the AVF or waters that supply the AVF. Mining will <br />not interrupt, discontinue, or preclude farming on the AVF and will not materially damage the quantity and <br />quality of water in surface and underground water system that supply the AVF, or portions of it. The minimal <br />effects of mine subsidence or mine dewatering on the AVF, as described under Rules 2.05.6(3), Protection of <br />the Hydrologic Balance, 2.04.7, Hydrology Description, and 2.05.6(6), Subsidence Survey, Subsidence <br />Monitoring, and Subsidence Control Plan, will not negatively impact agricultural activity. Based on this <br />information, subsidence -related impacts will be of limited magnitude, will occur progressively during and <br />shortly after coal extraction, and will be effectively mitigated by the natural response of the dynamic stream <br />system. Continuous discharge of water from the underground into the stream system will have a negligible <br />impact under normal conditions, and will not result in unacceptable levels of dissolved solids with regard to <br />agricultural and forage crop tolerances even under worst-case conditions. Dewatering will have a positive effect <br />on AVF productivity downstream from discharge points, especially during years of low stream -flow. <br />The locations of road crossings through the Fish Creek AVF were chosen to minimize disturbance to the AVF. <br />As presented on Map 15, Alluvial Valley Floor and Water Rights, the areas to be affected are narrow and should <br />not limit any of the functions of the AVF. Specific details of road construction will be submitted to CMLRD for <br />evaluation and approval prior to the construction. In view of these facts, it is proposed that a negative <br />determination be made for this Rule. <br />is <br />As TCC continues to expand its operations in the NMD and proceed with development and mining in the WMD, <br />additional information is required to meet the requirement of the above regulation. It should be understood that <br />TCC will be subsiding segments of Foidel and Fish creeks and the associated AVF areas, as it mines the coal <br />reserves located in the NMD. The result is that the portions of the associated valley floors will be flooded and <br />associated grazing activities precluded. <br />Exhibit 4c-2, Kaman Tempo Report- Foidel Creek Mine, November 1987, provides detailed information <br />concerning the Foidel Creek AVF. The report was updated with a soils investigation preformed by Habitat <br />Management, and the report is presented in the Exhibit 4c-4, Fish Creek Alluvial Valley Floor Soil <br />Investigation. The data derived from the backhoe soil tests pits was used to conduct Exhibit 4c-4, Figure 1, Fish <br />Creek AVF Profile #1, Figure 2, Fish Creek AVF Profile #2, Figure 3, Fish Creek AVF Profile #3, Figure 4 ,and <br />Fish Creek AVF Profile #4. The figure provides a look at the physical configuration of the valley floor and Fish <br />Creek. <br />PR09-08 2.06-13 04/29/09 <br />