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Applicant's Response to Second Adequacy Letter <br />Grand River Park Project, DRMS File M-2006-046 <br />January 2, 2007 <br />Page 18 <br />surface or groundwater systems," Rule 6.4.7(2) requires the applicant to provide <br />information that may be used to assess the presence of and impact to surface <br />water "structures" (subparagraph (a)), aquifers (subparagraph (b)), and water <br />quality standards (subparagraph (c)). Similarly, Rule 3 establishes performance <br />standards related to specific quantitative and qualitative aspects of the hydrologic <br />system (e.g., conveyances, aquifers, potential transport of pollutants), but <br />impacts to wetlands and riparian vegetation are not addressed. In sum, the <br />Martin & Wood report does not identify any particular "significant, adverse <br />impacts" to natural resources, and the Division provides no citation for a standard <br />by which the operator may determine whether an assumed impact to wetlands or <br />riparian woody plants will be judged to be "minimized." <br />While the applicant notes for the record the lack of regulatory guidance <br />concerning the need for, or performance criteria for, wetland and riparian <br />mitigation measures, best practices that will preserve and enhance vegetative <br />values on the site are integral to the applicant's mining and reclamation plans. A <br />200-foot buffer between the affected area and the northeastern boundary of the <br />property attenuates the effect of land disturbance and de-watering on the <br />Colorado River riparian zone. The proposed mining plan also calls for the <br />avoidance of wetlands, and wetland features are planned as an integral <br />component of the proposed reclamation plan. For further reference, during <br />mining all wetland areas will be equipped with water recharge capabilities, <br />including exfiltration trenches, level spreaders, and pumps as necessary. Finally, <br />the elimination and control of weeds is a critical step in the implementation of a <br />reclamation plan that will preserve significant vegetative values on the subject <br />site. <br />Please see the attached adequacy response letter prepared by Martin & Wood <br />Water Consultants for further detail regarding the Division's inquiry in Comment <br />21 e. <br />f. The Martin & Wood Consultants ground-water model and assessment <br />predicts a number of significant, adverse hydrologic impacts to water and <br />vegetative resources in the immediate and surrounding areas based on <br />the proposed de-watering operations. The authors suggest installation of <br />a slurry wall prior to de-watering and excavation as a method to eliminate <br />and/or minimize the various predicted impacts. What is not clearly defined <br />is the maximum pumping rate required specifically for each cell or phase <br />to maintain a de-watered mining condition; and the allocation of where and <br />how pit de-watering flows will be returned back to the Colorado River in <br />such a way so as to minimize potential adverse impacts to ground-water <br />wells, irrigation ditches, wetlands, riparian vegetation, and any other <br />resources dependant on surface or ground-water resources. In response, <br />please confirm whether a slurry wall will or will not be installed prior to <br />