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winter months? If so, is there a grading plan designed to direct culvert overflow away from the <br /> fine-grained tailings in the event of culvert overtopping/failure? <br /> 9.6.2 Create Additional Wetlands on the south side of the Swan River Valley adjacent to the site. <br /> The plan calls for the documentation of fill placement through a post-construction survey of the <br /> site. Is there a survey of current conditions onsite with which to compare the post-construction <br /> survey? Are there any plans to conduct one to establish a baseline for post construction <br /> conditions? <br /> Long-term viability will be verified by obtaining 70%or more areal coverage is there any <br /> desired species diversity that should be comparable to other existing natural wetland areas near <br /> the site? <br /> 9.6.3 Divert Swan River flows upstream of the site to the north channel of the Swan River. <br /> Again,a post construction survey is proposed in the plan, a pre-construction survey will be <br /> important for comparison of pre and post remediation conditions. This survey will also be <br /> crucial in designing the diversion channel for the appropriate flow conditions. <br /> Channel design specifics are not included in the application. What will the design flow for the <br /> diversion channel (i.e. Q 1.5,Q2.33,Q100...)? <br /> 9.6.4 Improve the Fine-Grained Tailings Cover below the former mill area. <br /> The application calls for 70%coverage of the cap with Canada reedgrass and tufted hairgrass. <br /> This mix may not provide sufficient species diversity. Consultation with the USFS or DOW for a <br /> seed mix that allows for greater plant species diversity as well as the addition of a legume to the <br /> seed mixture will allow for adequate species diversity and long-term nitrogen fixation thereby <br /> increasing cap stability. <br /> While the application calls for determining the long-term viability of the vegetative cover <br /> through annual inspections over a three-year time frame, CDPHE recommends an inspection <br /> period of approximately 5 years to adequately assess the long-term viability of the cover. <br /> In order to finalize the application,you may submit an addendum to the application that would address <br /> these questions or you may withdraw your application. Please notify us regarding how you wish to <br /> proceed. If you require additional time to gather data you may request an extension to a specific date. <br /> The current review period expires October 29,2004. If you have any questions concerning this letter <br /> please feel free to contact me at(303)692-3426. <br /> Sincerely, <br /> Kevin Mackey <br /> Environmental Protection Specialist <br /> CC: RV040914-1 <br />