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• conditions will need to be evaluated and submitted in order to provide design for Pond 1 (Appendi>: 4.6-B; Tables 4.6-A, 5, 8, 9). IT WAS MUTUALLY AGREED BY MLRD AND P&M TO DEFER RESPONSE TO THESE COMMENTS UNTIL THE MOFFAT STABILITY STUDY IS COMPLETED. NO CHANGE IN THE PERMIT TEXT IS REQUIRED BY THIS COMMENT. B. Based on the design submitted for Pond 1, the dewatering device is improperly located and a revised design should be submitted. The current placement (Exhibit 4.6-4) is located at a position higher than the ma::imum sediment storage level. Any water entering the pond from runoff events smaller than the design storm, pit pumpage, spoils aquifer inflow, and other sources will fill the pond to the principal spillway level. This standing water will provide insufficient detention for the 10 year, 24 hour design storm. IT WAS MUTUALLY AGREED BY MLRD AND P&M TO DEFER RESPONSE TO THIS COMMENT UNTIL THE MOFFAT STABILITY STUDY I5 COMPLETED. NO CHANGE IN THE PERMIT TEXT IS REQUIRED BY THIS COMMENT. • A revised design should be submitted which locates a dewatering device at the mar.imum sediment storage level and provides sufficient storage capacity for the design storm volume. The design should include the orifice size designed to provide 24 hour detention for the revised runoff volume of Pond 1, or demonstrate a 0.5 ml/L 24 hour mean settleable solids effluent concentration consistent with the discussion on Page 4.6-142 and 143. IT WA5 MUTUALLY AGREED BY MLRD AND P&M TO DEFER RESPONSE TO THIS COMMENT UNTIL THE MOFFAT STABILITY STUDY IS COMPLETED. NO CHANGE IN THE PERMIT TEXT I5 REQUIRED BY THIS COMMENT. C. Based on the design submitted for Pond 1, the emergency spillway is improperly located and sized; a revised design should be submitted. The emergency spillway for Pond 1 (Exhibit 4.6-4) is located 0.7 feet above the principal spillway. Rule 4.05.6(3)(d) requires a minimum of 1.0 foot between the principal spillway and crest of the emergency spillway. The designs submitted for all ponds which incorporate this requirement should be reviewed and revised as appropriate. IT WA5 MUTUALLY AGREED BY MLRD AND P&M TO DEFER RESPONSE TO THESE COMMENTS UNTIL THE MOFFAT STABILITY STUDY IS COMPLETED. NO CHANGE IN THE PERMIT TEXT IS REQUIRED BY THIS COMMENT. . The Pond 1 emergency spillway design flow will need to take into consideration the 25 year, 29 hour design flow routed from Ponds 2B-7B in addition to the design plan for the contributing basin area between these ponds and Pond 1. A revised design consistent with this condition should be submitted (Tables 4.6-10, 11, lla;