The storm surge simulations were performed using the state-of-the-art coastal circulation model ADvanced CIRCulation for Model for Oceanic, Coastal and Estuarine Waters (ADCIRC – www.adcirc.org). The ADCIRC mesh is comprised of a high-resolution grid covering FEMA Region III that was appended to a previously developed grid of the western North Atlantic, the Gulf of Mexico and the Caribbean Sea. Specifically, the grid covers the area from the 60 deg west meridian to the US mainland. Within FEMA Region III, the grid extends inland to the 15m contour to allow for inland storm surge flooding. In this region, the grid was designed to resolve major bathymetric and topographic features such as inlets, dunes and river courses as identifiable on the detailed DEM, satellite images, and NOAA charts.
Quality assurance and control was performed as the mesh was developed by conducting a visual comparison between the elevations represented in the mesh and that in the original maps or data. The mesh was adjusted by hand to maintain element shapes that are as close to equilateral as possible, although this was done based on a qualitative inspection and not on specific quantitative criteria. Once developed, a final comprehensive review of the ADCIRC mesh was conducted. This final review ensured that the terrain elevations were accurately represented in the grid. In addition, the review ensured that relevant morphological features, such as barrier islands, levees, dunes, and shoals were correctly represented. Furthermore, all hydraulic pathways, such as inlets, large rivers, navigation channels, and canals were reviewed to ensure adequate representation in the model grid. The review was carried out to certify that the data are consistent with FEMA and industry standards.
Refinement of the ADCIRC mesh was also made during model calibration and validation, by comparing modeled tides with published values from NOAA, and by comparing modeled maximum water levels from storm hindcasts with measured water levels and high water marks.