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• Table 2.2-2 Sediment Pond Cleanout A July 25, 2005 storm generated peak flows in the Munger Creek watershed that exceeded those associated with the 10 year event. The watershed "F" channel overtopped and filled the refuse pile sediment pond with mud, water and debris. The sediment pond was partially dewatered. The water level is approximately two feet below the invert of the emergency spillway. There are approximately 900 cubic yards of mud, water and debris remaining in the sediment pond. The material from the sediment pond will be placed on top of the coverfill pile in one of the three disposal cells shown on the following sketch. The disposal cells will be created by flattening the top of the coverfill pile and creating at least a 2.5 feet high berm or cut slope around each cell. The three disposal cells have about 900 cubic yards of total capacity at a depth of 1.5 feet. A pump will initially be used to attempt to pump some material to the disposal cell(s). Material will then be excavated with a track hoe and hauled to one of the disposal cells with a front end loader. As the work progresses, a ramp will be • constructed into the sediment pond so the track hoe can reach as much sediment as possible. A temporary 12 inch diameter culvert will be installed in Ditch I to facilitate loader travel. The 12 inch diameter culvert. is capable of handling the 100 year, 2.1 cfs design flow, through Ditch I. A clam shell may be utilized to complete the sediment removal process. The clean out project including the repair of the primary spillway pipe will take about two weeks. Final disposal of the sediment will depend on its physical and chemical properties. it is likely the material can be used as coverfill and therefore be left in place. The sediment will be seeded this fall with the soil stabilization seed mix. Mulch will not be utilized since it is unlikely the sediment will have dried sufficiently to support pedestrian traffic. • M~ Volume I 08/12/05