Modeling of Barrier Breaching During Hurricanes Sandy and Matthew

Physical processes driving barrier island change during storms are important to understand mitigate coastal hazards and evaluate conceptual models for evolution. Spatial variations in topography, landcover characteristics, nearshore back-barrier hydrodynamics can yield complex morphological that requires of increasing resolution physical complexity predict. Using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system, we investigated two breaches occurred on Fire Island, NY Hurricane Sandy (2012) at Matanzas, FL Matthew (2016). The model employed a recently implemented infragravity (IG) wave driver represent effects IG waves water levels sediment transport. simulated breaching other changes with good skill both locations, resolving differences breach Island was 250 m west observed breach, whereas Matanzas within 100 breach. Implementation vegetation module COAWST allow three-dimensional drag over dune improved by decreasing flows across back-barrier, as opposed varying bottom roughness did not positively alter response. Analysis indicated far-field local influenced creation evolution, including remotely generated surge, but also surge propagation through waterways. This work underscores importance systems when predicting extreme events.