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The floodways presented in this study were computed for certain stream segments on the basis of equal-conveyance reduction from each side of the floodplain. Floodway widths were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. The results of the floodway computations are tabulated for selected cross sections (see Table 2, Floodway Data). In cases where the floodway and I-percent-annual-chance floodplain boundaries are either close together or collinear, only the flood way boundary is shown. The area between the floodwayand I-percent-annual-chance floodplain boundaries is termed the floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water-surface elevation of the base flood more than 1 foot at any point. Typical relationships between the floodwayand the floodway fringe and their significance to floodplain development are shown in Figure 1. I- 1-PERCENT -ANNUAL-CHANCE FLOODPLAIN FLOODWAY 1'" FRINGE _I FLOODWAY LOOOWAY FR'NGE STREAM CHANNEL FLooO ELEVATION WHEN CONFINED WITHIN FLOODWAY ENCROACHMENT AREA OF FLOODPlAIN THAT COULD BE useD fOR DEVELOPMENT BY RAISING GROUND LINE AIlS THE FLOOD ELEVATION BEfORE ENCROACHMENT. LINE CD IS THE FLOOD ELEVATION AFTER ENCROACHMENT. .SURCHARGE IS NOT TO EXCEED 1.0 fOOT (FfA REQUIREMENT) OR LESSER AMOUNT tF SPEcrFIED BY STATE. Figure 1. Floodway Schematic 5.0 INSURANCE APPLICATION For flood insurance rating purposes, flood insurance zone designations are assigned to a community based on the results of the engineering analyses. These zones are as follows: Zone A Zone A is the flood insurance rate zone that corresponds to the I-percent-annual-chance floodplains that are determined in the FIS report by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no Base Flood Elevations (BFEs) or depths are shown within this zone. 7