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<br /> <br />e <br /> <br />e <br /> <br />e <br /> <br />Redstone <br /> <br /> <br />analysis indicated that the levee, especially the downstream <br />segments, lacks adequate density and cross-se~tion geometry as <br />evidenced by the water which was observed seeping through the <br />levee during the inspection. Extensive waterside slope erosion <br />was also noted in some segments of the levee, highlighting the <br />need for riprap (or other form of erosion protection) in any <br />future improvements. The report also identifies sloughing, <br />voids, crown depressions, and animal burrows, as well as dense <br />vegetation and brush growing in some portions of the levee. <br /> <br />Given this information, it would appear ill-advised to <br />proceed to raise the. existing levee, at least without further <br />geotechnical analysis. It is possible that some segments of the <br />levee could be raised. However, extensive subsurface <br />explorations (including a determination of foundation conditions) <br />along the entire levee should be done to determine if any <br />sections are viable. <br /> <br />POTENTIAL PROJECT QUANTITIES AND COSTS <br /> <br />The fOllowing quantities and costs are based on similar <br />levee analyses in western Colorado, including Grand Junction and <br />Lake City. Some costs may be higher due to the relatively remote <br />location or unknown subsurface geotechnical conditions; other <br />costs may be lower. These estimates should be used as a guide <br />only since there may be substantial variation for the cost of <br />feasibility studies, design work (and associated geotechnical <br />studies and testing); preparation of plans and specifications; <br />and for the construction supervision and administration. <br /> <br />The quantities listed below assume the following cross- <br />section geometry and construction methods (typical of Corps <br />levees) as shown on Attachment 4. <br /> <br />· A l2-foot crown with a 6-inch layer of aggregate road base <br />to provide an inspection/maintenance road. <br />· A lV on 3H waterside slope. <br />. A lV on 2H lands ide slope. <br />· Soil stripping and an inspection/cutoff trench equal <br />to the levee height. <br />· A riprap/filter blanket 15 inches thick for lOO-year <br />protection and 18 inches thick for 500-year protection <br />with adequate toe protection against erosive <br />velocities. <br />· Tie-ins to high ground at the upstream and downstream <br />ends. <br />· Dust control measures during construction and seeding of <br />the lands ide slope to prevent erosion following <br />construction. <br /> <br />8 <br />