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<br />The floodways presented in this study were computed for certain stream segments on <br />the basis of equal-conveyance reduction from each side of the floodplain. Floodway <br />widths were computed at cross sections. Between cross sections, the floodway widths <br />and boundaries were determined photogrammetrically. The results of the flood way <br />computations are tabulated for selected cross sections (see Table 3, Floodway Data). In <br />cases where the floodway and loo-year floodplain boundaries are either close together <br />or collinear, only the floodway boundary is shown. <br /> <br />The area between the floodway and loo-year floodplain boundaries is termed the <br />floodway fringe. The floodway fringe encompasses the portion of the floodplain that <br />could be completely obstructed without increasing the WSEL of the tOO-year flood <br />more than 1 foot at any point. Typical relationships between the floodway and the <br />floodway fringe and their significance to floodplain development are shown in <br />Figure 21, Floodway Schematic. <br /> <br />I <( <br /> <br />100- YEAR FlOOOPLA!H <br />FlOOOWAY 1-41---- FLOOOWA, Y <br />FRINGE <br />STREAM <br />CHANNel <br /> <br />~I <br /> <br />LOODWAY <br />FRiNGE <br /> <br />flOOD ELEVATION WHEN <br />CONFINED WITHIN FlOODWA Y <br /> <br /> <br />liNE AI IS THE flOOD ELEVATION BEFORE ENCROACHMENT. <br />UNE CD IS THE FLOOD ELEVATION AFTER ENCROACHMENT. <br />.SURCHARGE IS NOT TO EXCEED 1.0 FOOT (FIA REQUIREMENn OR LESSER AMOUNT IF SPEOFIE08Y STATE. <br /> <br />Figure 21. Floodway Schematic <br /> <br />5.0 INSURANCE APPLICATION <br /> <br />For flood insurance rating purposes, flood insurance zone designations are assigned to a <br />community based on the results of the engineering analyses. These zones are as follows: <br /> <br />Zone A <br /> <br />Zone A is the flood insurance rate zone that corresponds to the loo-year floodplains that are <br />determined in the FIS by approximate methods. Because detailed hydraulic analyses are not <br />performed for such areas, no Base (tOO-year) Flood Elevations (BFEs) or depths are shown <br />within this zone. <br /> <br />38 <br />