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1. the Yampa River in the Big Bottom area <br /> 2. the Williams Fork River near its confluence with the Yampa River. <br /> Map 35A and Map 52 indicate the locations of AVF well sites and the location of alluvial valley <br /> floors. The Coy well drilled into the alluvium of Flume drainage functions as a point of compliance <br /> well. Four wells are drilled into the Pyeatt alluvium, well Jl is located in the Johnson drainage <br /> alluvium and one of the three GLEV wells in the Deacon drainage reached the alluvium at the very <br /> north east corner of the permit. This GLEV well is located downgradient of any mining to the east <br /> that may occur in the future. These wells constitute an environmental monitoring system during <br /> surface coal mining and reclamation operations continuing until release of all bonds in accordance <br /> with Rule 3 (4.24.4). <br /> Four gulches (No Name, Johnson, Pyeatt, and Flume) are determined not to be alluvial valley floors <br /> based on their absence of water availability sufficient for flood-irrigation or sub-irrigation <br /> agricultural activities. <br /> Potential impacts to the Yampa River AVF resulting from the proposed mining operation are <br /> negligible. Generally, the Yampa River AVF receives very little of its water supply (surface and <br /> ground water)from the proposed mine area. The majority of the flow in the river and subsequent <br /> recharge to the alluvial aquifer derive from the headwaters portions of the drainage, far upstream <br /> from Trapper. The applicant states that the contribution of surface water from the Trapper mine is <br /> insignificant as per page 2-533 of the permit application. <br /> This is substantiated by seepage, runoff, and potentiometric studies in Appendix H of the permit <br /> application. Based on the information presented by the applicant, the Division finds that proposed <br /> surface coal mining operations will not interrupt, discontinue, or preclude farming on the Yampa <br /> River AVF, nor materially damage surface or ground water quantity or quality in systems supplying <br /> the Yampa River AVF (4. 24.3(l)), (4.24.3(3), and 2.06. 8(5)(a)(11)). <br /> The potential for impacts from mining to the Williams Fork AVF is also negligible. The Williams <br /> Fork River is located south of the proposed mining area. Almost exclusively, spring snowmelt <br /> comprises the only surface discharge from sediment ponds in the drainages flowing towards the <br /> Williams Fork River. It is likely that much of the discharge from these ponds infiltrate into the <br /> permeable Twentymile Sandstone outcrop prior to reaching the Williams Fork River. Therefore,the <br /> Division finds that the proposed surface coal mining operations will not interrupt, discontinue, or <br /> preclude farming on the Williams Fork AVF, and will not materially damage the quantity or quality <br /> of water in surface or ground water systems that supply the Williams Fork AVF (4.24. 3(l)), <br /> (4.24.3(3), and 2.06. 8(5)(a)(11)). <br /> The Division finds that: <br /> 1. Proposed mining activities comply with the requirements of the Act and the <br /> Regulations with respect to alluvial valley floors, (2. 06.8(5)(a)(111)). <br /> 2. The surface coal mining and reclamation operations will be conducted to preserve the <br /> essential hydrologic functions of alluvial valley floors outside the permit area and to <br /> reestablish the essential hydrologic functions of alluvial valley floors within the affected area <br /> 20 <br />