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I ~ c) The planting of willows and other vegetation will further anchor the entire design and <br />provide aesthetic value. <br />d) The minimum height of the top of dam is 20 feet. At the midway point of the <br />embankment height, the width is 60 feet. For a flood to erode through this width, <br />considering the outside protection, it would have to be much stronger than a 100 year <br />event. If any erosion were to occur during a 100 year event, it will be repaired once the <br />storm subsides. For a storm of this magnitude, many other places on the river (outside of <br />this permit area) will experience much more serious damage. <br />e) For the upper part of the embankment, inside and outside, topsoil will be placed to a <br />depth of 12 inches, which will subsequently be planted with an aggressive seed mix. <br />f) According to the La Plata County flood manager, the average velocity of the 100 year <br />floodwater is 8 feet per second. The outside of the embankment will be lined with an <br />Excelsior fabric that alone will handle 8 feet per second without erosion. This combined <br />with vegetation that will further anchor the fabric and the fact that the jetty will be <br />slowing the water down that arrives at the embankment means that the combination of <br />these items is more than adequate. <br />Rau mentions risks of river channel movement to the west during flood events introduced <br />by removal of the existing large rock terrace. The terrace is not being removed. A lake is <br />being excavated in the inner part of the terrace and a solid plan for maintaining a <br />permanent embankment between the two is shown in the application. Risks of river <br />channel movement are also mentioned. If anything, the risk of river channel movement is <br />lessened. The armoring of the bank to protect the lake will also protect the downstream <br />lands more than the current bank of loose gravel. If a 100 year event occurs now, the bank <br />could erode, capturing the sewage ponds and causing more problems for al] owners <br />downstream. We propose replacing the ponds with a lake that is topsoiled, vegetated and <br />valuable to wildlife along with embankment protection which does not currently exist for <br />the ponds. <br />3) Letter from Office of State Engineer <br />This letter basically requires a well permit for the lake evaporation and an identification <br />of all wells within 600 feet of the permit boundary. This is being provided to them. Since <br />this area of the Animas River is under appropriated, no augmentation plan is needed. <br />4) Letter from Dennis Pierce <br />Truck traffic and exhaust issues are being addressed at the County level and are not part <br />. of the DMG's jurisdiction. It should be pointed out, however, that the truck traffic of 254 <br />2 <br />