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<br />001813 <br /> <br />Criteria for improvement of the levees centers around federal <br />agency requi rements for 1 evee systems to provi de 3- to 4-feet of <br />freeboard over the 100-year flood profil e. Addit i ona 1 desi gn <br />criteria of the COE is outlined in Design and Construction of <br />levees (Ref. 7). This criteria would be implemented in the design <br />phase of any improvements. As well, technical data requirements <br />of the FEMA (Ref. 9) would be implemented in design so as to <br />permit the design to justify a flood insurance map change to <br />remove the 100-year floodplain from the City and County in and <br />around Alamosa. <br /> <br />Certain sandbars in the river, along with associated vegetation, <br />would be removed. <br /> <br />Seepage control during high flood flows is a problem throughout <br />the study reach and should be addressed during design. <br /> <br />C. South (right) side, U.S. 160 to D&RGWRR <br /> <br />The 1 evee along the right side should be raised to provide the <br />required freeboard. Widening of the levee should be included to <br />provi de access contro 1 and an impermeable core constructed to <br />mitigate seepage. <br /> <br />The levee at the bend in the river requires increased height and <br />riprap armour to provide adequate freeboard and protection to the <br />levee system. <br /> <br />I <br /> <br />D. North and East (left) side, State Avenue to U.S. 160 <br /> <br />Access control fencing is required where the levee system borders <br />potential private and public access points. <br /> <br />Seepage concerns also need to be addressed through this reach. <br /> <br />! <br /> <br />E. West (right) side, Cole Park to U.S. 160 <br /> <br />Raising and widening of the levee is required in the Cole Park <br />area. The levee should be constructed of select impermeable <br />material to reduce seepage through the levees. Riprap <br />stabilization is recommended along the park, as the river is <br />constricted and the flow velocities are directed at the levee <br />through this reach. <br /> <br />~ <br /> <br />e <br /> <br />Levee construction is proposed upstream of the U.S. 160 bridge to <br />train the high flows through the structure. The new levee should <br />be riverward of the existing levee. <br /> <br />No access control is needed through this reach of the levee. <br /> <br />-21- <br />