Flood Compound Modelling: Framework and Application to a Coastal Environment

Compound flooding refers to the phenomenon where multiple drivers such as rainfall, storm surge, and river discharge, happen simultaneously or consecutively within a relatively brief timeframe (Guan et al. in Water Security 19, 2023 [7]). This is the case of hurricanes and events of heavy rainfall where the combination of drivers can increase the hazard and subsequent impacts in comparison to a single driver. Therein lies the importance of compound flood events from a risk standpoint. This study presents a framework to model compound floods using the recent open-source software Super Fast Inundation of Coast (SFINCS). It proposes an automatization to select the Area of Interest (AOI) and the organization of input data for the model. The methodology was applied to simulate the past hurricane Florence that impacted the U.S. Eastern coast in 2018. A sensitivity analysis was carried out in this modelling with different sources of meteorological forcing and configurations. Results were contrasted with hydrometric measurements and showed that there are limitations with the bathymetry data that can lead to differences in comparison with hydrometric records, and regarding the coastal areas, the boundary condition is crucial for the good performance of the model. Overall, the document here presented sets the first steps of an automated workflow for storm surge impact assessment.