Compound Flooding during Hurricane Florence (2018)

Abstract:

As part of the effort in simulating compound flooding during all major hurricanes in the past decade along the US east coast and the Gulf coast, this study applies the technology pioneered in Hurricane Irene 2011 (Ye et al. 2019; Zhang et al. 2020) and Hurricane Harvey 2017 (also presented in this session), to simulate the compound effects during Hurricane Florence 2018. Specifically, the 3D baroclinic hydrodynamic model (Semi-implicit Cross-scale Hydroscience Integrated System Model; schism.wiki) is configured to handle flood routing in the watershed, so that its coupling with the hydrological model (National Water Model) can occur at higher ground elevations than in traditional storm surge simulations. This allows the model to account for the compound effects of river flooding, rainfall and storm surge. Thus, the relative contributions of these three processes can be calculated to show the study site’s spatially-varying vulnerability to compound flooding. In addition, the effect of barrier islands on the local surge patterns and the propagation of the freshwater plume into the coastal ocean are presented.