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A <br />• • <br />determine whether small area exemption status is appropriate. <br />In the designs, please account for the fact that the two areas <br />seem to be placed at the bottom of drainage watersheds, which <br />could result in significant erosion due to runoff from a storm <br />event. <br />29. Referring to Map 5-1, Vegetation Sample Locations, in Exhibit <br />5, and the photographs in Exhibit 5, it appears that most of <br />the vegetation sampling sites are located within the most <br />heavily vegetated area of the general site. Consequently, less <br />heavily vegetated areas lying to the east, but still draining <br />to mine ponds, may be under-represented in the sampling. If <br />you disagree with this assessment, please explain. If you <br />agree that the assessment may be true, please perform an <br />appropriate vegetation sampling program in areas outside of <br />the present sampling area. If the results show a difference <br />from the present sampling results, curve numbers may need to <br />be changed. <br />30. The annotation for the gob pile pond needs to be added to Map <br />21-1, Drainage Plans, and Map 20, Sedimentation Control Plan. <br />31. The outslope of pond A is listed as 1.5H:1V on Map 22-A, Pond <br />A Design. Rule 4.05.6(11)(f) requires that no pond embankment <br />be steeper than 2H:1V without an appropriate demonstration <br />that the slope is stable. On page 2.05-31, pond A is referred <br />to as a dugout pond. However, examination of Section A - A', <br />on Map 22-A, seems to suggest that an embankment is present. <br />Rule 4.05.9(6) requires that excavated impoundments meet all <br />of the requirements of Rule 4.05.9 that apply. Rule 4.05.9(2) <br />requires that all temporary impoundments that have a dam must <br />follow, among other rules, Rule 4.05.6(li)(f) which refers to <br />dam stability demonstrations. <br />If you agree that pond A has an embankment, please provide the <br />appropriate demonstrations that show that the outslope at <br />1.5H:1V is stable. If you do not agree that pond A has an <br />embankment, please explain why. <br />32. In Volume IV of the permit application, in Appendix B, ditch <br />designs for the coal waste pile are presented. In Appendix C, <br />ditch designs for the coal waste pile are also presented. The <br />ditch designs in both appendices are different from each <br />other. Why are there two different presentations for these <br />ditches and which presentation applies to the in-the-field <br />situation? <br />33. Drawing 95266-04 shows that the side slopes for the runoff <br />control ditches are 2H:1V. However, the ditch designs in <br />Appendix B of Volume IV list iH:iV for the side slopes for all <br />of the ditches. In Appendix C, the ditch designs for the crest <br />ditch and the upper diversion show side slopes of 1H:1V. <br />6 <br />