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Mr. Michael Cunningham 3 <br />CDRMS <br />April 22, 2014 <br />Response: <br />The hydraulic analyses for the South TSF Contact channel have been revised to show a <br />2 -feet deep, V- shaped ditch with 2 to 1 side slopes. A cross section has been added to <br />Drawing D -2 showing the location of the South TSF Contact channel in relation to the <br />East Diversion channel. <br />6. Appendix B, Weir Report. It appears the weir analysis presented uses a sharp- crested weir <br />analysis. The drawing section on DR -2 shows it is a broad - crested weir. Also, the weir <br />coefficient presented is 3.0. Assuming the weir /spillway is lined with riprap, it will not be <br />smooth and the coefficient should be somewhere between 2.6 and 2.8. Please revise the <br />weir analysis appropriately. <br />Response: <br />The Weir Report for the TSF emergency spillway and South Contact channel sediment <br />has been modeled as a broad - crested weir, and revised using a Weir Coefficient of 2.6. <br />7. Appendix B, Spillway Chute. The Division could not find a hydraulic analysis for the spillway <br />chute (that portion below the crest of the spillway and intercepting channel running along the <br />toe the east TSF contact. Please provide this analysis, keeping in mind the maximum slope <br />for riprap of 40 percent. <br />Response: <br />A hydraulic analysis of the spillway chute has been added to Appendix B of the report, <br />and a detail of the TSF Spillway Chute has been shown on Drawing DR -2. The slope of <br />the outside embankment of the TSF stands at a slope of 2.5 to 1 (40 %). The <br />intercepting channel (TSF Spillway channel) for the spillway is distinct from the TSF <br />South Contact channel on the east and south side of the TSF. The TSF Spillway <br />channel diverges from the outside toe of the TSF to direct flows to the West Diversion <br />channel. The proposed diversion, spillway, and contact channels have been labeled on <br />Drawing DR -1 to be consistent with those in Appendix B and Table 3 in the report. <br />Drawing DR -1. <br />8. Please label the channels on drawing DR -1 consistently with those presented in Table 3 and <br />analyzed in Appendix B to reduce potential confusion. Also, depending on the response to <br />Comment 3 above, changes may need to be made to Basin OS 1. <br />Response: <br />The proposed diversion, spillway, and contact channels have been labeled on Drawing <br />DR -1 to be consistent with those in Appendix B and Table 3 in the report. <br />9. The Division believes there is insufficient capacity for sediment retention at the southwest <br />corner of the TSF. Please include an additional sediment basin near the southwest corner of <br />the TSF. <br />