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the mining years was performed. For the south ditch, Year 1 contained the <br />highest peak flows while Year 20 contained the highest peak flow in the <br />northern ditch. Table 4.6-11 shows the design calculation summaries for both <br />the south and north ditch. The computer generated results and watershed <br />dissection for the south ditch are provided in Appendix 4.6-D The computer <br />results for the north ditch are provided in Appendix 9.6-8 (Final Year 10-y r, <br />24-hour storm) while the watershed dissection is shown in Exhibit 4.6-2. <br />Ditch profiles and cross sections are shown in Exhibit 4.6-5. The inlet on <br />the south side of the pond was designed using the SEDCAD+ computer model. The <br />results of the modeling effort are provided on page 4.6-33a and a graphical <br />representation of the results is provided on page 4.6-33b. <br />4.6.1.6 Sediment Pond and Diversion Ditch Construction <br />The sediment pond and diversion ditches will be built using scrapers, <br />dozer, or other excavating machines. The primary spillway of the pond will be <br />placed with the aid of a backhoe. The emergency spillway will be built to <br />design specifications utilizing a dozer or other suitable equipment to <br />construct the channel. Prior to constructing the embankment, the foundation <br />area will be cleared of all organic matter and the surface scarified. The <br />fill material to be used will be free of sod, large roots, other large <br />vegetation matter and frozen soil. Placing and spreading of the fill material <br />will be started at the lowest point of the foundation with the fill being <br />brought up in horizontal layers with a maximum thickness of two feet to <br />facilitate compaction. <br />A small area of disturbance around the pond will occur during <br />construction. The design of the pond (lowest surface disturbance area to pond <br />volume possible) and careful supervision during construction will keep this <br />disturbance to a minimum. A11 areas of disturbance due to construction <br />requirements will be appropriately seeded and mulched following construction. <br />4.6.1.7 Sediment Control for Small Area Exemptions <br />Exhibits 4.3-1 (areas) which will not have topsoil removed, 4.6-17, 4.6- <br />21 and 4.6-23 show the locations of all the small area exemptions at Edna <br />4.6-33 May 14, 1993 <br />