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NOV 181981 BOOK 43 PAPE 13-7, with wave crest elevations of 12 feet, will be encountered at the Atlantic Ocean open coast shoreline during a 100 -year storm tide. These waves are completely dissipated, and the 100 -year storm surge is stopped at the seaward end of the primary coastal dune by rising ground elevations. No shore protection structures are located within the 100 -year Atlantic coastal flood plain in Indian River County. Wave heights in the Indian River vary in relation to the extent of open water and the stillwater elevations calculated in the various areas. These waves are dissipated primarily on the western shore of Indian River by a combination of rising ground elevations and ob- structions in the flood plain such as buildings and vegetation. In some cases, islands in Indian River with sufficient ground elevation and obstruction characteristics can dissipate wave energy. Areas along the western shore of Indian River which have been bulk -headed are provided protection from waves by depth -limitation when the bulk- heads are built to sufficient elevations. These structures are ex- pected to remain intact during a 100 -year storm tide. After flood insurance zones were established for the study area, the FIRM for Indian River County was revised to incorpora-te the new zone information. This.map contains the official delineation of flood insurance zones and base flood elevations. In preparing the revised FIRM, updated topographic information was used to revise the Atlantic coastline and some zone boundaries in areas not affected by the wave height analysis. Corporate limits and cultural features were revised using current county and co:.,nunity maps. The assignment of proper actuarial insurances rates requires that frequency and depth of flooding be estimated as accurately as possible. Because waves can add considerably to expected flood depths, it is important that insurance rates consider this additional hazard. The Federal Emergency Management Agency has developed a process to transform the data from this study into flood insurance criteria. This process includes the determination of Flood Hazard Factors and the designation of flood insurance zones and rates. RECO?247-Z"DATIONS : It is recommended that Ind--i-an River -County Ordinance 78-25 refer_J.-_, to building construction under the Federal Flood Insurance Program be amended by: 1) Adopting the revised flood Emergency Management Agency tions for purposes of flood maps, provided by Federal , as the base flood eleva- plain management. 2) Adjusting the ordinance content where applicable so that it is consistent Faith wave height criteria in the revised FIRM. It is further recommended that the Board of County Commissioners hold a public hearing on December 16th , 1981, to adopt a flood pro- tection ordinance amending Ordinance 78-25.