Sea Level Rise Affecting Eastern Florida Peninsula
The City of Vero Beach must use their GIS department to document the existing elevation of the various city benchmarks in order to determine the extent of subsidence within the city limits and immediately adjacent areas. Then, compare current elevations with historical data to determine the subsidence rate within the City of Vero Beach. GIS must document the finished floor elevation and/or elevation of the lowest structural member of all city buildings and develop a chart comparison referencing the Finished Floor to the current FEMA flood elevation.
The local building regulations in Indian River County are based upon the 7th Edition Florida Building Code (2020) with updates approved by the Florida Building Commission every three years. The next code cycle is progressing and the new 8th Edition Code will be issued in 2023. In the 7th Edition, the FBC Building, FBC Residential, FBC Existing Building, and FBC Mechanical, Plumbing and Fuel Gas were modified/updated to address flooding and resulting damage in Coastal High Hazard Zones (Zone V) and Coastal A Zones. However, it maintained the FEMA recommended freeboard guidelines. (Freeboard is the difference between the 100-year flood elevation and the finished floor of a building in its simplest form). The FEMA required Freeboard for any structure is 1.0 foot. Therefore, a slab-on-grade foundation must be set at least 1 foot above the 100-year flood elevation. Example: If the base flood elevation is 8.0 msl/NGVD then the finished floor of the building must be at least 9.0 msl/NGVD irrespective of the natural ground elevation. Therefore, most new construction in Coastal Zone A requires fill dirt as can be seen on most of the new single-family homes under construction.
To better prepare for the future sea level rise; I would recommend that the City Staff develop, and the City Council adopt, a revised ordinance where-in the required Freeboard would be increased from the FEMA mandated 1.0 feet to 1.5 feet, at a minimum.