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<br />4.2 Floodways <br /> <br />Encroachment on floodplains, such as structures and fill, reduces <br />flood-carrying capacity, increases flood heights and velocities, <br />and increases flood hazards in areas beyond the encroachment. One <br />aspect of floodplain management involves balancing the economic <br />gain from floodplain development against the resulting increase in <br />flood hazard. For purposes of the NFIP, a Hoodway is used as a <br />tool to assist local communities in this aspect of floodplain <br />management. Under this concept, the area of the lOO-year <br />floodplain is divided into a floodway and a floodway fringe. The <br />floodway is the channel of a stream, plus any adjacent floodplain <br />areas that must be kept free of encroachment so that the lOO-year <br />flood can be carried without substantial increases in flood <br />heights. Minimum Federal standards limit such increases to 1. 0 <br />foot, provided that hazardous velocities are not produced. <br /> <br />A floodway was not calculated for the flooding source studied. <br /> <br />5.0 INSURANCE APPLICATION <br /> <br />For flood insurance rating purposes, flood insurance zone designat ions <br />are assigned to a communi ty based on the results of the engineering <br />analyses. These zones are as follows: <br /> <br />Zone A <br /> <br />Zone A is the flood insurance rate zone that corresponds to the <br />toO-year floodplains that are determined in the Flood. Insurance <br />Study by approximate methods. Because detailed hydraulic analyses <br />are not performed for such areas, no base flood elevations (BFEs) <br />or depths are shown within this zone. <br /> <br />Zone AE <br /> <br />Zone All is the flood insurance rate zone that corresponds to the <br />lOO-year floodplains that are determined in the Flood Insurance <br />Study by detailed methods. In most instances. whole-foot BFEs <br />derived from the detailed hydraulic analyses are shown at selected <br />intervals within this zone. <br /> <br />Zone X <br /> <br />Zone X is the flood insurance rate zone that corresponds to areas <br />outside the SOO-year flooding where average depths are less than 1 <br />foot, areas of lOO-year flooding where the contributing drainage <br />area is less than 1 square mile, and areas protected from the 100- <br />year flood by levees. No BFEs Or depths are shown wi thin thi s <br />zone. <br /> <br />8 <br />