Barrier Breaching Versus Overwash Deposition: Predicting the Morphologic Impact of Storms on Coastal Barriers

Waves and water level setup during storms can create overwashing flows across barrier islands. Overwashing cause erosion, breaching, inlet formation, but their sediments also be deposited form washover fans. These widely different outcomes remain difficult to predict. Here we suggest that a breach develops when the sediment volume transported by exceeds subaerial volume. We simple analytical theory estimates from storm characteristics, morphology, dune vegetation, which used assess deposition breaching likelihood. Our suggests width surge height are two important controls on breaching. test our with hydrodynamic morphodynamic model Delft3D as well field observations of 21 fans 6 breaches formed Hurricane Sandy. There is reasonable correspondence for natural not developed coasts, where traditional transport equations do readily apply. formulations formation overwash improve long-term island models.