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~~ • overexcavation in the foundation area and construction of a recompacted low-permeability baze m which the embankment wall will be founded. Construction methods and requirements are discussed in the 6/3/97 Lincoln DeVore letter. 25. Please assist in locating page B-]74 in Appendix B. Response: Afrer reviewing the DMG's commen[s and bath the original Appendix B and the reformatted Appendix B submitted with the TR-29 application, it waz determined that much of the information included in the original Appendix B provided a valuable historical perspective and should be retained. Accordingly, revised drainage design documentation for the proposed expansion areas is provided az astand-alone document to be inserted at the end of the original Appendix B (following page B-173). The reference to page B-174 is, therefore, no longer accurate. Text discussions along with the revised Appendix have been reviewed and revised to provide appropriate and consistent references. Pleaze see accompanying revisions. 26. Figure 4.1 of the WESTEC report, "Sub Basins and Major Flow Routes ;shows an area east of Ditch D-4 which would appear to drain into D-4. The calculations do not include the area, so it would appear that lY/ESTEC bas determined that this are will not drain to D-4. Please explain the field conditions which will or do currently route flow from this area elsewhere. Please see attached Figure 4.1 for a graphic representation of this concern. Response: The area to the east of Ditch D-4 will drain downgradienc co the ditch. Figure 4.1, because it is part of an existing report, haz not been revised. Drainage and ditch sizing • calculations have however, been revised to correct this omission and revised calculations are provided for insertion at the end of Appendix B. Please see accompanying revisions. 27. Figure 4.1 also shows a Ditch D-3. The referenced feature appears to be the crown of the refuse pile, and not a ditch. Please clarify or remove the Ditch D-3 label. Response: As indicated by the ditch design calculations provided on pages 5 an 6 of Appendix B to the WESTEC Report, the feature labeled az D, on Figure 4.1 is the existing natural drainage above the upper bench of the refuse pile which drains areas A,, and At6. . .Design calculations, az presented in Appendix B, and Map 3211, Drainage and Sediment Control Plan, are consistent in indicating the natural drainage channel. As noted above, Figure 4.1 will not be revised. 28. The designs for Ditch D-1 do not include runoff from subwatershed Asb Based on the proposed construction plan for the refuse pile, it would appear that this area will drain to D-1. Please revise the ditch design, or clarify the proposed pile construction if DMG's assumption is incorrect. Please see attached Figure 4.1 for a graphic representation of this concern. Response: As indicated by the drainage design calculations presented in Appendix B to the WESTEC Report, the upper surface of the refuse pile will be crowned and sloped back into the natural hillslope with area Asb draining to the west to Ditch D-1. The drainage and ditch sizing calculations have been revised to correct this error. Pleaze see accompanying revisions. • 29. The watersheds shown on Figure 4.1 appear to be inaccurate. Please see attached Figure 4.1, which indicates the watersheds apparent to DMG. Unless OCM has information unavailable to DMG which further explains OCM's demarcation, the figure should be revised.