2007-07-30_GENERAL DOCUMENTS - C1981041

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permit area is located except for undeveloped rangelands which 'are not significant to farming (4.24.3(1) end 2.06.8(5)(a)(i)). i 2. The proposed surface coal mining operations would not matet~ially damage the quantity or quality of water in surface and undergroundwatersysterns that suFiply those alluvial valley floors or portionsof alluvial valley floors (4.24.3(3) and 2.06.8(5)(a)(ii)). I Water for flood irrigated agricultural activities is obtained from h`vo sources. The upper terzace areas at the mouth of Rapid Creek are ircigated by flow from ~he Rapid Creek system. As discussed above, mining would not affect either water quality or quantity in the Rapid Creek/Cottonwood Creek stream system. Agicultural activities on the lower terraces and floodplain area 'are flood irrigated with water derived froth the Colorado River. Some of the lower areas may be marginally subirzigated by alluvial groundwater. The proposed operation would not affect the quantity of flow in the Colorado River stteam/alluvial aquifer system. Disposal of coal'i~efuse material in an adjacent area, and the discharge of mine water from underground workings could affect water quality. The Division has assessed the possible affects of these activities and has not identified any significant change in water quality. 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 floors (4.24.2(1)).1 , The essential hydrologic functions ofthe Colorado River alluvial ~/alley floor are those geologic, hydrologic,~topographic, and soil characteristics that give the arE:a the ability to support flood irrigated agricultural activities. Subirrigation is a marginal functioh that is limited to a few of the lower areaslwhich are also capable of flood irzigation. Since no, mining activities would take place within the alluvial valley floor, the geologic, topographic, rind soil characteristics of the alluvial valley floor would be unaffected. Mining activities are expected to have no effect on the Rapid Creek/Cottonwood Creek hydrologic system. Water quality in the Colorado River stream alluvial aquifer system may be slightly degraded but thad ability to flood ircigate the alluvial valley floors would not be affected. I; The proposed operation is in compliance with the requirements of this section I 7-13-07 PR-03 Findings.dac Permit Revision No. 3 i Permit No. C-1981-041 July 30, 2007 Page 58