Laserfiche WebLink
<br />includes a floodplain boundary map designed to HHlilst eommuni tip!,; In <br />developing sound floodplain management measures. <br /> <br />4.1 Floodplain Boundaries <br /> <br />To provide a national standard without regional discrimination, <br />the 1 percent annual chance ODD-year) flood has been adopted by <br />FEMA as the base flood for floodplain management purposes. For <br />each stream studied by detailed methods, the boundaries of the <br />100-year floodplain boundaries have been delineated using the <br />flood elevations determined at each cross section. <br /> <br />Between cross sections, the boundaries were interpolated using a <br />Kucera and Associates, Inc., topographic map of Georgetown, at a <br />scale of 1 :100 with 2-foot contours; and a McDermid Engineering <br />Associates, Inc., map, scale 1 :100 with I-foot contours, of <br />Georgetown Lake vicini ty, with some surveying conduc ted by the <br />CWCB. <br /> <br />The 100-year floodplain boundaries are shown on the Flood <br />Insurance Rate Map. On this map, the 100-year floodplain boundary <br />corresponds to the boundary of the areas of special flood hazards <br />(Zone AE). Small areas within the floodplain boundaries may lie <br />above the flood elevations, but cannot be shown due to limitations <br />of the map scale and/or lack of detailed topographic data. <br /> <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 floodway is used as a <br />tool to assist local cODUllunities in this aspect of floodplain <br />management. Under this concept, the area of the 100-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 100-year <br />flood can be carried without substantial increases in flood <br />heights. Minimum federal standards limit such increases to <br />1.0 foot, provided that hazardous velocities are not produced. <br /> <br />Floodways were not computed for the flooding sources studied for <br />this study. <br /> <br />8 <br />