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FFa ~~~%yey Upper Animas Sand and Gravel !,k~,,, ` J~~ February, 12, 2006 '~~°?o `~~0 o,~~~~O,~e/a Re: File No. M-2005-065, Adequacy Issues '~~/s~~~ Adequacy Issue No. 1 ~O/~j. Two small flood channels enter the proposed pit area on the northwest side adjacent to the Animas River (Exhibits B-1, E, S, E-1). Channel 1 enters the proposed permit area approximately 350°southwest of the north- west permit corner. This channel is thought to be manmade. Channel 2, a much smaller channel, enters the permit area approximately 100 feet ftiYthertY~o!.,the southwest. Attached is a 6vestS9ater Associates, Inc. report prepared for Jack, Jr. and Barbara Clark dated January 25, 2006. The report demonstrates that the Clark Pit is located in an area of change in the Animas River. Above the pit site the river is a narrow channel high energy flow regime. Below the pit site the river is a lower energy stream with a braided channel with heavy vegetative cover. From this report it is expected that if a 100 year flood event were to enter the channels adjacent to and progressing into the pit area the flows would be low energy. Upper Animas Sand and Gravel will armor the two small floodway channels into the pit area. The channels will be armored using 2.5' diameter and larger materials. The channels will be maintained at the existing size, elevation and gradient into the pit. The armoring will begin at the permit boundary and proceed to the pit edge and then approximately 8 feet down the mined pit slope. This will place the end of the armor 6 feet below the lake water elevation(Exhibit E-3}, In all construction the top of the Rip Rap will be maintained at the current ;rqurt9 elevation. In addition an outlet spillway will be constructed on the southern bank of the settling pond. This spillway will be constructed using 2.5' and larger materials and will be embedded at existing elevations and. will be approximately 10 feet wide. The spillway will begin in the banlt between the lake and settling pond and end at the south permit boundary. The slopes of the spill- way will extend 3 feetbelow the completed pond water water level(Exhibit E-2).