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Appendix B <br />PROTECTION OF THE HYDROLOGIC BALANCE <br />BOWIE N0.2 MINE <br />COAL MINE WASTE DISPOSAL AREA NO.2 <br />Notes for Calculations: <br />1.Pages 3-10 present a spread sheet calculation of the required capacity of Sediment Pond F <br />based on the 10-year, 24-hour event, and sizing of the emergency and embankment spillways. <br />Pages 11-13 are SedCad pages which verify the water storage capacity required for Pond F. <br />Pages 14-15 are the Structure Networking for the Pond F drainage area, and pages 16-19 are <br />the Subwatershed Hydrology Details. <br />2.Page 21 shows the peak flow used to size the emergency and embankment spillways using <br />the 25-year,24-hour event in the SEDCAD4 program. <br />3.Design points are shown on Figure 2. <br />4.Ditches were sized using SEDCAD4. Ditches were sized using the 100 year, 24-hour event and <br />begin on page 22. <br />5.During June of 2017, the hydrology of the top of gob pile #4 was revised, the PHC and <br />affected ditches and culverts were revised accordingly. <br />6. During June 2025, the grade of Ditch F-7 was revised, affected PHC pages were revised <br />accordingly. <br />ENGINEER'S CERTIFICATION <br />The calculations and information presented on the following pages with dates of 01/15, 06/17, <br />and 06/25, were prepared by me during the months of January 2015, June 2017, and June <br />2025, the information presented is true and correct to the best of my knowledge and belief. <br />Ta I P.E. 06/30/2025___________ <br />Date <br />MR-211 App. B-1 06/25