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The Rapid Creek alluvial valley floor receives the water supply <br /> from the Rapid Creek/Cottonwood Creek stream system. Since no <br /> surface facilities are located within this system, and no disturbed <br /> runoff or mine water would be discharge to Rapid Creek or <br /> Cottonwood Creek, the proposed operations will not affect water <br /> quality. The Division has estimated that stream flow depletion in <br /> the absence of flow through fractures , either natural or as a <br /> result of subsidence, would be less than 0.003 cfs . Such a minor <br /> loss would not be detectable . The permittee has proposed a limited <br /> extraction mine plan beneath the streams , and subsidence effects <br /> would not be expected in these areas . No major natural fractures <br /> have been identified in the permit application. Minor fractures <br /> are undoubtedly present, but may not be open to the passage of <br /> ground water . The required surface water and mine water monitoring <br /> will detect any unanticipated change in the existing hydrologic <br /> system. <br /> 3. Surface coal mining and reclamation operations would be conducted <br /> to preserve, throughout the mining and reclamation process , the <br /> essential hydrologic functions of the alluvial valley floor. <br /> The essential hydrologic functions of the Rapid Creek alluvial <br /> valley floor are those geologic , hydrologic, topographic , and soil <br /> characteristics that give the area the ability to support flood <br /> irrigated agricultural activities. Since no mining activities <br /> would take place within the AVF, the geologic , topographic , and <br /> soil characteristics of the AVF would be unaffected. Rapid Creek <br /> and Cottonwood Creeks would be undermined under a limited <br /> extraction plan and mining would not effect the surface water <br /> 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, <br /> discontinue or preclude farming on an alluvial valley floor that is <br /> irrigated or naturally subirrigated . <br /> The area designated as alluvial valley floor lies outside of the <br /> permit area, downstream from the proposed operations . As a result, <br /> there would be no surface disturbance within the AVF , and the area <br /> would not be undermined. No irrigation occurs along this stretch <br /> of the river where the permit area is located except for <br /> 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 <br /> damage the quantity or quality of water in surface and underground <br /> water systems that supply those alluvial valley floors or portions <br /> 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 <br /> two sources . The upper terrace areas at the mouth of Rapid Creek <br /> are irrigated by flow from the Rapid Creek system. As discussed <br /> above, mining would not affect either water quality or quantity in <br /> the Rapid Creek/Cottonwood Creek stream system. <br /> -44- <br />