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' o Transit Mix Concrete Co. <br /> shows segments of F1-1 may be as steep as 33%. Please be sure all steep channel segments that <br /> will require more robust armoring are addressed in Table G-5. <br /> Response: Exhibit G and Table G-5 have been revised to include additional details and <br /> armoring requirements on steep segments of the project channels. <br /> 5. Page G-23, first paragraph, detention basins in bedrock. The narrative states "... where the <br /> detention basins will be constructed into bedrock, the sediment detention basins walls will be <br /> sloped at 0.5H:1V." Furthermore, Figure G-15 suggests these detention basins may be as <br /> deep as 20 feet. Please provide narrative addressing how these ponds, as a potential wildlife <br /> attractant will be protected against wildlife falling in and becoming injured from falls down <br /> steep slopes or become trapped. Please also address how these steep slopes will be protected <br /> from personnel and equipment from accidentally entering the steep sided pond. <br /> Response: The sediment detention basins will not detain water beyond 72 hours or 120 <br /> hours, depending on the storm size, so they will not attract wildlife. Figure G-15 includes <br /> an access ramp, which provides egress for any animals that may enter the basin area. <br /> Berms or baffles will prevent personnel and equipment from accidentally entering the basin <br /> areas. <br /> 6. Page G-23, first paragraph, detention basin drain time. The narrative states "The outlet pipe <br /> will be controlled by an orifice plate at the pipe inlet and will be sized to drain the 100-year <br /> storage volume in less than 120 hours, as required by Colorado Department of Water <br /> Resources guidelines." Figure G-15, Note 4 states the drain time is 72 hours. The Division's <br /> understanding is the guideline is 72 hours. Please clarify which is intended and make <br /> appropriate corrections to the text or Figure. <br /> Response: The Exhibit G text and Figure G-15 have been updated to clarify the basin <br /> drain time. <br /> 7. Page G-24, Table G-6, runoff volume. Based on the narrative at the bottom of page G-3, the <br /> Division expected to see the most conservative runoff volumes used for sediment pond <br /> design. The volumes presented in Table G-6 for basins P-Plant-I and P-Plant-2 do not <br /> correspond to the largest estimated volumes from the five SEDCAD models output files for <br /> these two ponds. Model P2 estimated 24.10 ac-ft for basin P-Plant-1, and model P5 estimated <br /> 20.14 ac-ft for basin P-Plant-2. Please explain why the lower volumes (19.99 and 17.31, <br /> respectively) were presented in Table G-6. <br /> Response: Exhibit G and Table G-6 have been revised to include the most conservative <br /> runoff volumes for each structure. <br /> 8. Page G-24, section c, Culverts. The narrative states "Culverts will be used ... in limited areas <br /> as means of conveying temporary flows down steep slopes via drop culverts." The Division <br /> could not find permit level drawings or figures depicting how these proposed drop culverts <br /> would be configured. Please provide conceptual drawings showing the proposed drop culvert <br /> configuration and the means of energy dissipation. <br /> Hitch Rack Ranch Quarry(M-2017-049) <br /> Response to Comments—March 9,2018 <br />