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<br />Table 5. A comparison of the floodwa.y outlines for existing a.nd cleared <br />channel conditions on Plates 3 and 4, show that the~ floodway wa.s narrowed <br />slightly by the channel clearing. The reduction in ~rater SUrfaCE! elevations <br />and floodway area was generally not large l~nough to make this a viable flood <br />mitigation measure. <br /> <br />3.5 Channel Improvement <br />considered in this study. <br />Platte River, the channel <br />option because of its need <br />and sand bars. <br /> <br />Option. A channel impz:'ovement opti.on was not <br />Because of the braided. nature of the South <br />improvement op1:ion was not considered a viable <br />for continual maintenance' to remove vegetation <br /> <br />3.6 Alternative Levee Option. An alternative to the proposed levee <br />by the City of Sterling is to build a levee just outside of the existing <br />conditions floodway shown on Plate 3 and 4" The levee aU.gnmEmt generally <br />follows the proposed city levee alignment where possible. A short dashed <br />line on the left bank shows where the levE!e depart from this alignment. A <br />short dashed line on the right bank shows where the floodway for this option <br />departs from the existing conditions floodway. This levee placement would <br />not provide the city with as much land a~:J protected by the city proposed <br />levee alignment, but would offer protection to a major portion of that land. <br />A lOO-year levee constructed for this option should be constructed at <br />least as high as the floodway water surface elevations in Table Four with an <br />additional three feet of freeboard. <br /> <br />3.7 Floodway Mitigation with Levee Option. Another option would be to <br />build the proposed city levee and then calculate a new floodway with the <br />levee in place. The right bank encroachments were widened all the way to <br />the county road, but failed to maintain a 1.0' or less rise in the floodway. <br />Once that option had failed, the left bank encroachments for the floodway <br />were then widened until an alignment \oli1:h a 1.0' or less rise was <br />calculated. The floodway for this option was calculated and the outlines <br />are shown on Plates 3 and 4. A floodway data table for this option in shown <br />in Table Six. This option may require nE~gotiations for compensation with <br />the land owners on the right bank and upstream whose land would be <br />susceptible to increased flood elevations. <br />A lOO-year levee constructed for this option should be constructed at <br />least as high as the floodway water surface~ E!levations in Table Four with an <br />additional three feet of freeboard. <br /> <br />7 <br />