Storm Surge Simulations for Hurricane Hugo (1989): On the Significance of Inundation Areas

Abstract

The storm surge generated by Hurricane Hugo (1989) is reproduced for the purposes of (1) evaluating the significance of including inland flooding areas and corresponding levels of spatial resolution and (2) assessing the spatial variability of near-inlet boundary forcings with respect to storm surge hydrographs. The study focuses on the coastal regions of South Carolina, incorporating inundation areas between Charleston and Shallotte Inlet and including Winyah Bay and the Waccamaw River. The region of interest is modeled with five variations of an unstructured, finite-element mesh, including a localized coarse grid with and without floodplains, a localized fine grid with and without floodplains, and a large-domain approach that includes floodplains and the continental shelf and deep ocean. Simulation results demonstrate that the inclusion of inland flooding areas significantly improves the description of storm surge generation within coastal regions. While the large-domain approach is shown to be beneficial, it is determined that the coarse mesh resolution of the floodplains is sufficient. Computed water surface elevations at specific locations surrounding Winyah Bay Inlet indicate that storm surge hydrographs are highly spatially dependent near inlets, as opposed to the astronomical tides, which exhibit minimal variance in space around the inlet environment.