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<br />stability. Therefore, all dam crest raises greater than 9 feet include costs for <br /> <br />a modification to the embankment in the form of berms for increased embankment <br /> <br />stability. The stability of any selected raise would need to be verified through <br /> <br /> <br />a comprehensive stability and seepage analyses during subsequent phases of the <br /> <br />studies. <br /> <br />ENVIRONMENTAL CONSIDERATIONS <br /> <br />A preliminary environmental evaluation was made for the alternatives. <br /> <br />ALTERNATIVE 1 - WIDEN EXISTING SPILLWAY <br /> <br /> <br />This alternative consists of enlarging the existing spillway channel and <br /> <br />contains four options. These options are to enlarge the spillway without any darn <br /> <br />raise, and to enlarge the spillway with dam raises of 3, 9, or 15 feet. <br /> <br />The present spillway has developed into an area of significant wildlife <br /> <br />habitat over the years since it was constructed. Portions of the bottom of the <br /> <br /> <br />spillway have developed into permanent wetlands which contain animal species such <br /> <br /> <br />as pheasant and nesting waterfowl. The spillway side slopes are vegetated with <br /> <br /> <br />a mixture of native and nonnative grasses, forbs, and some woody species. The <br /> <br />spillway cut is recognized by area >rildlife experts as having significant <br /> <br />wildlife values. <br /> <br />Widening of the spillway, regard~ess of which option were chosen, would <br /> <br /> <br />seriously impact the present resources. Essentially all of the present <br /> <br />vegetation would be lost, as would the a~sociated wildlife. It is theoretically <br /> <br /> <br />possible to mitigate most of these losses; however, such an effort would be <br /> <br /> <br />costly and would involve many years before the area could once again function as <br /> <br /> <br />a significant wildlife habitat unit. From an aesthetic viewpoint. this <br /> <br /> <br />alternative would cause significant impacts since the mature vegetation is much <br /> <br /> <br />more visually pleasing than would be the bare slopes that would result from <br /> <br />construction. <br /> <br />56 <br />