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and Number of Dams and Dozer Basins for Erosional Control of Reclaimed Lands for <br />Bond Release Under a Variety of Channel Conditions Using SEDCAD Modeling ", <br />"Appendix A through H ", "Figures 1 through 10 ". <br />Trapper Response to 23a: The reconstructed drainage model has been included in its <br />entirety in a new volume of Appendix Q. This is section XXXVII of Volume VII -C of <br />the permit within Appendix Q: Drainage and Sediment Control Plan. <br />b. Revised section 4.8.1.3 needs to include wording to commit to construct the post mine <br />drainages in accordance with the typical design depicted on Figures 4.8 -1a and 4.8 -1b. <br />Trapper Response to 23b: Wording has been added to section 4.8.1.3 to commit to <br />reconstruct drainages as applicable to Figures 4.8 -1a and 4.8-1 b. <br />c. Proposed Figures 4.8 -1c and 4.8 -1d depict graphs that can be utilized to determine the <br />number of check dams to be installed within a section of reconstructed drainage based on <br />drainage area and a curve number at a 10 or 15% slope. The curve number used to <br />generate these graphs was 78 and 72 and represents a portion of a reclaimed watershed at <br />different stages of reclamation. The Division believes that a 78 and 72 curve number used <br />to determine the number of rock check dams does not reflect the worst case scenario of <br />the land condition contributing to the drainage channel at the time of construction. During <br />the meeting, Trapper explained that they would actually like to vary the curve number <br />used to determine the number of check dams to be installed in a given portion of channel <br />based on the reclamation stage of the watershed contributing to the channel and that they <br />did not intend to use a design base on only the two curve number presented (78 and 72). <br />Given this, the Division believes Trapper needs to either revise Figures 4.8 -1c and 4.8 -1d <br />or add additional figures for all of the curve numbers they intend to use to determine the <br />number of checkdams to be installed. Also, please include additional permit text to <br />discuss what criteria will be used to select a given curve number. <br />Trapper Response to 23c: Additional figures have been included in section 4.8.1.3 to <br />detail check dam requirements for curve numbers 67 and 83. These figures have been <br />rearranged as Figures 4.8 -1c thru f. An example of the criteria and procedures used to <br />select the design parameters of a reconstructed drainage has been included. Curve <br />numbers will be determined by area in regard to the age of the reclamation and other site <br />specific conditions of ground cover. Curve number selection is substantiated by prior <br />determinations and research included in Appendix Q. <br />d. It was discussed that the slopes depicted on the figures discussed above do not <br />represent the range of slopes encountered within a reclaimed watershed. For the new <br />and/or updated figures, please include additional slopes for the various curve numbers to <br />be used to ascertain the number of check dams to be installed. <br />Trapper Response to 23d: Figures 4.8 -1 c thru f have been revised/included to show <br />additional check dam requirements in relation to slope and applicable curve numbers. <br />Values are now representative of slopes ranging from 5% to 25% to better reflect all <br />conditions encountered on the site. <br />Page 12 <br />