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<br /> <br />e <br /> <br />e <br /> <br />e <br /> <br />Redstone <br /> <br /> <br />ITEM <br /> <br />100-YEAR <br />Protection <br />Proiect <br /> <br />500-YEAR <br />Protection <br />proiect <br /> <br />Excavation (stripping, inspection, <br />& toe trenches) (cubic yards) <br />Embankment Material (cubic yards) <br />stone Protection (tons) <br />Filter Fabric (square yards) <br />Seeding & Dust Control (acres) <br />Stabilized Aggregate Road Base (tons) <br /> <br />6,000 <br />5,000 <br />6,000 <br />7,000 <br />2 <br />700 <br /> <br />9,000 <br />8,000 <br />8,000 <br />9,000 <br />2.5 <br />700 <br /> <br />Based on unit costs developed by the Corps for other recent <br />projects in western Colorado, the total project cost estimate <br />range for 100- and 500-year protection would be approximately <br />$400,000 to $500,000 and $500,000 to $600,000, respectively. <br />These estimates used a 25 percent contingency and included the <br />cost of relocation for a utility pole presently in the levee <br />alignment. The lower portion of the range estimate assumed an <br />additional 12 percent was included for planning, engineering, and <br />design and 8 percent for construction management. The higher <br />portion of the range is to account for unforeseen difficulties in <br />construction. The estimates did not include any real estate <br />costs. Pitkin County indicated that for purposes of this report, <br />the assumption should be made that all necessary easements are in <br />place. The project cost could be somewhat less if some of the <br />existing levee materials are determined to be suitable for reuse. <br /> <br />SUMMARY AND CONCLUSIONS <br /> <br />This analysis indicated that the expected water-surface <br />profiles for the 100- and 500-year flood events are very similar <br />to those developed by FEMA in the 1980's. Consequently, the FEMA <br />flood plain (shown on Attachment 2) should still be considered <br />reliable. <br /> <br />The existing levee should not be considered adequate to <br />raise given its present condition (at least not without a <br />detailed geotechnical investigation). Data developed to date <br />indicate the compaction and design of the existing levee to be <br />generally inadequate. The levee lacks sufficient height and/or <br />freeboard, erosion protection, proper side slopes, crown width <br />and cover, and interior drainage provisions through much of the <br />levee reach. Proper design of any future levee improvements <br />should consist of an extensive engineering effort, including a <br />feasibility level analysis (to include testing of the levee <br />embankment soils and foundation and a sediment transport <br />analysis), design and cost estimates, and plans and <br /> <br />9 <br />