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2. The proposed surface coal mining operations would not materially damage the quantity and <br />quality of water in surface and groundwater systems that supply these alluvial valley floors or <br />portions of alluvial valley floors (4.24.3(3)). <br />The Rapid Creek alluvial valley floor receives the water supply from the Rapid <br />Creek/Cottonwood Creek stream system. Since no surface facilities are located within this <br />system, and no disturbed runoff or mine water would be discharge to Rapid Creek or <br />Cottonwood Creek, the proposed operations will not affect water quality. The Division has <br />estimated that stream flow depletion in the absence of flow through fractures, either natural or as <br />a result of subsidence, would be less than 0.003 cfs. Such a minor loss would not be detectable. <br />The permittee has proposed a limited extraction mine plan beneath the streams, and subsidence <br />effects would not be expected in these areas. No major natural fractures have been identified in <br />the permit application. Minor fractures are undoubtedly present, but may not be open to the <br />passage of groundwater. The required surface water and mine water monitoring will detect any <br />unanticipated change in the existing hydrologic system. <br />3. Surface coal mining and reclamation operations would be conducted to preserve, throughout the <br />mining and reclamation process, the essential hydrologic functions of the alluvial valley floor <br />(4.24.2(1)). <br />The essential hydrologic functions of the Rapid Creek alluvial valley floor are those geologic, <br />hydrologic, topographic, and soil characteristics that give the area the ability to support flood <br />irrigated agricultural activities. Since no mining activities would take place within the AVF, the <br />geologic, topographic, and soil characteristics of the AVF would be unaffected. Rapid Creek <br />and Cottonwood Creeks would be undermined under a limited extraction plan and mining would <br />not effect the surface water system that supplies the alluvial valley floor. <br />Colorado River Alluvial Valley Floor - Findings <br />1. The proposed surface coal mining operations would not interrupt, discontinue or preclude <br />farming on an alluvial valley floor that is irrigated or naturally subirrigated. <br />The area designated as alluvial valley floor lies outside of the permit area, downstream from the <br />proposed operations. As a result, there would be no surface disturbance within the AVF, and the <br />area would not be undermined. No irrigation occurs along this stretch of the river where the <br />permit area is located except for undeveloped rangelands which are not significant to farming <br />(4.24.3(1) and 2.06.8(5)(a)(i)). <br />2. The proposed surface coal mining operations would not materially damage the quantity or <br />quality of water in surface and groundwater systems that supply those alluvial valley floors or <br />portions of alluvial valley floors (4.24.3(3) and 2.06.8(5)(a)(ii)). <br />Water for flood irrigated agricultural activities is obtained from two sources. The upper terrace <br />areas at the mouth of Rapid Creek are irrigated by flow from the Rapid Creek system. As <br />discussed above, mining would not affect either water quality or quantity in the Rapid <br />Creek/Cottonwood Creek stream system. <br />Permit Revision No. 5 56 July 10, 2012 <br />