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Comprehensive Plan Coastal Management Element Line" (D.S.S.L.). Other than approved dune walkovers, minor structures or erosion control projects, construction is not allowed seaward (east) of this regulatory line. Within Indian River County, the Coastal Barrier Resource Act (CoBRA) recognizes and discourages development in two areas: an area south of Ambersand Beach on the northern portion of the barrier island; and an area in the southern portion of the barrier island near the Indian River - St. Lucie County line. Because these relatively undeveloped areas are recognized as having the greatest potential for storm damage, federal flood insurance is unavailable in these areas. Should a Category V storm event occur, much of the barrier island and particularly the areas identified by CoBRA could be completely destroyed. Even with significant measures in place to reduce potential storm damage, hurricanes Francis and Jeanne in 2004 caused wide -spread damage to structures along the beach as well as structures inland. Sea Level Rise Sea level rise (SLR) is typically defined in terms of either global (eustatic) sea level rise or relative sea level rise. Global sea level rise represents the averagenge in the height of all of Earth's oceans relative to the land. Conversely, relative sea level rise refers to measured changes in sea level heightpecific locations on land relative to localized variations in land elevation, including changes due to ocean rise and/or land subsidence. Global sea level rise is directly influenced by fluctuations in the mass or volume of the ocean. Fluctuations in the volume of the ocean are the result of climatological and geological forces such as thermal expansion and contraction, tectonic shift, lift/subsidence, and sedimentation, while ocean mass is affected by factors including melting or accretion rates of glaciers, snow accumulation, and global water storage and redistribution mechanisms. Based on the Intergovernmental Panel on Climate Change(IPCC) Fifth Assessment Report (AR5), many of these climate related phenomena have been directly influenced by greenhouse -gas emissions increases since the pre -industrial era and other feedback mechanisms. With respect to SLR, the IPCC AR5 indicates that global average_land and ocean surface temperatures will likely continue to increase and contribute to the acceleration of SLR encountered in the future. In Florida, baseline relative sea level measurements can be derived from historical tide gauge records of mean monthly sea level. In fact, average monthly sea level measurements have been recorded at tide stations located in Key West, Cedar Key, and Fernandina Beach for more than a century. The yearlya_ verages of these historic data, depicted in Figure 9.14, indicate a gradual trend of rising mean sea level between 1897 and 2017. Moreover, these data highlight regional variability that may be observed among local relative sea level datasets. Based on those data sets, sea levels at Kew Cedar Key, and Fernandina Beach rose approximately 12.72", 12.66", and 15.63" over the last 100 years. Community Development Department Indian River County 23 Appendix B