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discharge elevation up to the elevation of the emergency spillway. Please revise this page <br />accordingly to include this explanation. <br />Response -Appendix 2.05.3(3)-1 has been renamed Appendix 2.05.3(4)-1. The text has <br />been revised. <br />9. In Table 2 of the pond memo in Appendix 2.05.3(3)-1, design capacities of the three <br />sediment ponds are listed. Each pond's listed capacity is the total pond volume up to the <br />emergency spillways. However, since a sediment pond cannot be dewatered below the <br />lowest discharge elevation of the discharge structure, a sediment pond's designed capacity <br />has to be able to contain the runoff from the 10 year-24 hour event as measured from the <br />elevation of the lowest discharge point up to the elevation of the emergency spillway. Please <br />provide demonstrations that the three ponds have sufficient capacity above the lowest <br />discharge elevation to contain the runoff from a 10 year-24 hour event and revise the <br />sediment pond design capacities in Table 2 accordingly. <br />Response -Appendix 2.05.3(3)-1 has been renamed Appendix 2.05.3(4)-1. The ponds have <br />been redesigned to conform to DRMS requirement. Table 2 has been revised. <br />10. The three sediment ponds each use a gated drop inlet primary discharge structure. However, <br />the Sedcad program cannot model pond volumes, discharges and sedimentology for a gated <br />pond to show compliance with Rule 4.05.6 and 4.05.9. The Sedcad designs that were <br />submitted use an un-gated, self-dewatering drop inlet structure. As a consequence, the <br />designs do not match the proposed construction and the designs may be confusing. For <br />example, the Sedcad designs show that runoff from the 10 year-24 hour precipitation event <br />will flow out of the emergency spillway, which is not allowed under Rule 4.05.9(2)(b). <br />Please provide sediment pond designs that demonstrate that the gated sediment ponds will <br />comply with Rules 4.05.6 and 4.05.9. The demonstration can rely on pond water and <br />sediment storage volumes without the pond discharging and without sedimentology <br />demonstrations. <br />Response - The ponds have been redesigned to conform to DRMS rules. <br />11. In the first full paragraph on the fourth page of Appendix 2.05.3(3)-1, the first sentence <br />states that an emergency spillway with a height that is one foot below the top of the pond <br />embankment can be used. However, Rule 4.05.9(7)(d) requires that there be at least one foot <br />difference in elevation between the 25 year-24 hour precipitation event water level flowing <br />through the emergency spillway and the top of the embankment. For the sake of clarity, <br />please revise this statement on the fourth page to reflect the rule requirement. <br />Response -Appendix 2.05.3(3)-1 has been renamed Appendix 2.05.3(4)-1. The text has <br />been revised to address the issues. <br />12. On the fourth page of Appendix 2.05.3(3)-1, it is recommended that modifications to <br />sediment ponds NHN-001 and NHN-002 be used in order to avoid short circuiting. Please <br />revise the text to describe which modifications will be used, especially for pond NHN-002. <br />Also for pond NHN-002, please explain per Rule 4.05.6(7) why the spillway pipe could not <br />be located more towards the middle of the pond since it is now positioned very close to the <br />outlet of ditch NHN-002 North. <br />Response to First Adequacy Review Page 34