Modeling Compound Flooding from Hurricane Florence Using ADCIRC. Part II: Riverine Contributions

Hurricane Florence (2018) and several other recent hurricane events illustrate the enhanced impacts of the co-occurrence of storm-driven surge and extreme (record-setting) precipitation and resulting river flows on the coastal zone. If the riverine and coastal water levels co-occur in both space and time, the resulting compound flooding can greatly increase the inundation extents, damage, and effects on coastal resources and populations well beyond the impacts of individual water components. Recent compound flooding events have thus motivated new research and applications into optimal approaches to more accurately simulate, and eventually predict, their impacts. Part 1 of this presentation describes and details comprehensive hindcasts of Hurricane Florence using the ADCIRC model that include detailed reanalysis and advanced parametric hurricane winds and inland river discharges from USGS gauges. Results indicate varying significance of compound flooding depending on the size of the catchment - river - estuarine system. In this Part 2, we extend the Part 1 analysis to include river discharges from the NOAA National Water Model (NWM), available inundation extent data, and preliminary coupling approaches.