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<br />standards that can be adopted 4irectly or that can be used as a <br />basis for additional floodway studies. <br /> <br />Because of high-velocity condit~ons, the floodways were developed <br />for Fountain Creek, Ruxton Cre~k, Sutherland Creek, and Williams <br />Canyon by applying the allowa~le rise to the energy gradeline <br />instead of the water-surface ielevation. Floodways were also <br />identified by the criteria that iallow a maximum hazardous velocity <br />of 3 feet per second at the edge of the floodway fringe. These <br />hazardous velocity criteria proved to be determinant in the <br />floodway delineation. For Williams Canyon and Ruxton Creek, the <br />floodway boundary is the same as the 100-year flood boundary. A <br />floodway fringe has been compute~ for some areas along Fountain and <br />Sutherland Creeks without reaqhing the allowed l-foot rise in <br />energy gradeline or water-surface elevation. The data presented in <br />the Floodway Data Table repr~sents the computed water-surface <br />elevations. . <br /> <br />. <br /> <br />The floodways presented in thh study were computed for certain <br />stream segments on the basis of equal conveyance reduction from <br />each side of the floodplain. Floodway widths were computed at cross <br />sections. Between cross secti~ns, the floodway boundaries were <br />interpolated. The results o~ the floodway computations are <br />tabulated for selected cross s~ctions (Table 2). In cases where <br />the floodway and 100-year floo~plain boundaries are either close <br />together or collinear, only the floodway boundary is shown. <br /> <br />The area between the floodway and 100-year floodplain boundaries is <br />termed the floodway fringe. The floodway fringe encompasses the <br />portion of the floodplain that could be completely obstructed <br />without increasing the water-$urface elevation of the 100-year <br />flood by more than 1.0 foot at any point. Typical relationships <br />between the floodway and the f190dway fringe and their significance <br />to floodplain development are shown in Figure 4. <br />, <br /> <br />5.0 INSURANCE APPLICATION <br /> <br />For flood insurance rating purposes, flood insurance zone designations <br />are assigned to a community based 'on the results of the engineering <br />analyses. These zones are as follow~: <br /> <br />.. <br /> <br />Zone A <br /> <br />Zone A is the flood insurance I rate zone that corresponds to the <br />100-year floodplains that are' determined in the Flood Insurance <br />Study by approximate methods. Because detailed hydraulic analyses <br />are not performed for such akeas, no base flood elevations or <br />depths are shown within this zo~e. <br /> <br />. <br /> <br />Zone AE <br /> <br />Zone AE is the flood insurancJ rate zone that corresponds to the <br />100-year floodplains that are' determined in the Flood Insurance <br /> <br />14 <br />