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typically full of water? [s there any hydrologic connection between the ditch/lateral and the alluvial aquifer <br />[o be mined in or through? Please address. <br />22. The applicant states on page 9 that impacts to groundwater will occur as a result of the dewatering <br />operations which are necessary to expose and excavate [he gravel deposit on this site. <br />In conformance with Rule 6.4.7 (2)(b), please characterize the aquifer to be mined within or through. <br />Included in the characterization should be characteristics such as permeability, transmisivity, storage <br />coefficient, depth to groundwater, depth to bedrock or aquitard, groundwater gradient (flow rate & <br />direction), etc. <br />23. In conjunction with the applicant's statement on page 9 that impacts to groundwater will occur as a <br />result of dewatering operation, as a result of the unknown potential for dewatering impacts to the Clark <br />Ditch, and as a result of the objections received regarding, [he Division requests that the applicant provide <br />a detailed hydrologic assessment of the projected impacts to surface water and groundwater in the affected <br />land and surrounding area do [o dewatering when the pit excavation is at its maximum extent. The <br />hydrologic assessment should include a predicted cone of depression which defines [he vertical and lateral <br />extent of drawdown expected and an assessment of the water table impacts to such features as the Clark <br />Ditch, offsite wetlands, offsite woody riparian vegetation such as cottonwoods and/or willows, Trout <br />Creek, Yampa River, and any nearby groundwater users. (The cone of depression should be based on <br />known aquifer characteristics and on the pumping or drawdown rate necessary [o completely dewa[er the <br />pit from top to bottom and maintain a dry pit. The cone of depression should be predicted fora "worst <br />case" or dry time of year when pit dewatering may exacerbate already depressed water levels in the <br />affected land and surrounding area). For an assessment of potential impacts to any other groundwater <br />users, the hydrologic analysis may include the following information: [he depth and screened intervals to <br />which the well(s) are completed, [he rate of drawdown the groundwater user experiences after use, the <br />water levels in the well or aquifer after use, and whether the cone of depression created via pit dewatering <br />extends into the water level left after the groundwater users use. <br />24. Rule 3.1.6(1) specifies that disturbances to the prevailing hydrologic balance of the affected land and <br />of the surrounding area and to the quantity or quality of water in surface and groundwater systems bath <br />during and after the mining operation and during reclamation shat] be minimized. Therefore, in <br />conjunction with the hydrologic assessment and potential for adverse impacts via pit dewa[ering as <br />specified in Item 23 above, the Division requests that the applicant describe mitigation measures or <br />specific commitments that will be incorporated into the Regular 112 Application [o ensure that such <br />impacts to the hydrologic balance will be minimized. (The applicant has referenced on page 18 specific <br />agreements made with Routt County regarding site monitoring. The applicant may choose to incorporate <br />such commitments, and any others as appropriate, into this application). Please address. <br />25. An objection to the application has been filed over the concern that pit dewatering may cause material <br />injury to wells owned and operated by private citizens in the Town of Milner. (See attached objection <br />letter). Are such wells upgradient or downgradient from the Camilletti Milner Pit #2? What is [heir <br />approximate distance from the proposed operation? Are the wells in the Milner area completed into the <br />same alluvial aquifer that will be mined and dewatered at the Camilletti Milner Pit #2? Please respond. <br />26. The applicant states on page 9 that dewateting operations will generate approximately 750,000 gallons <br />per day or 521 gallons per minute. The July 20, 2001 letter from Paul Currier of Water Resource <br />Consultants, LLC estimates pit inflows ranging from 20 to 200 gallons per minute. The Division requests <br />that [he applicant clarify and quantify the maximum pit inflow rate expected during a maximum <br />disturbance scenario and provide supposing documentation to verify how the inflow rate was determined. <br />The inflow rate should be based on the aquifer permeability, area and depth of exposed pit wall(s), natural <br />