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<br />The floodways presented in this study were computed on the basis <br />of equal-conveyance reduction from each side of the floodplain. <br />The results of these computations were tabulated at selected <br />cross sections for each stream segment for which a floodway was <br />computed (Table 2). <br /> <br />As shown on the Flood Boundary and Floodway Map (Exhibit 2), the <br />floodway widths were determined at cross sections; between cross <br />sections, the boundaries were interpolated. In cases where the <br />boundaries of the floodway and the lOO-year flood are ei ther <br />close together or collinear, only the floodway boundary has been <br />shown. <br /> <br />The area 'between the floodway and the boundary of the IOO-year <br />flood is termed the floodway fringe. The floodway fringe thus <br />encompasses the portion of the floodplain that could be <br />completely obstructed without increasing the water-surface <br />elevation of the lOa-year flood by more than 1.0 foot at any <br />point. Typical relationships between the floodway and the <br />floodway fringe and their significance to floodplain development <br />are shown in Figure 11. <br /> <br />I" <br /> <br />100- YEAR FLOODPLAIN <br /> <br />-I <br /> <br />c <br /> <br />FLOODWA Y <br />FRINGE <br /> <br />1( <br /> <br />FLOODWA Y <br /> <br />LOODWAY <br />FRINGE <br /> <br />STREAM ~ <br />CHANNEL <br /> <br />FLOOD ELEVATION WHEN <br />CONFINED WITHIN FLOODWA Y <br /> <br /> <br />ENCROACHMENT <br /> <br />ENCROACHMENT <br />o <br />. <br /> <br />AREA OF FLOODPLAIN THAT COULD BE USED FOR <br />DEVELOPMENT BY RAISING GROUND <br /> <br />FLOOD ELEVATION BEFORE <br />ENCROACHMENT ON FLOODPLAIN <br /> <br />LINE AB IS THE FLOOD ELEVATION BEFORE ENCROACHMENT. <br />LINE CD IS THE FLOOD ELEVATION AFTER ENCROACHMENT. <br />*SURCHARGE IS NOT TO EXCEED 1.0 FOOT (FIA REQUIREMENT) OR LESSER AMOUNT IF SPECIFIED BY STATE. <br /> <br />Figure 11. Floodway Schematic <br /> <br />25 <br />