Formation of a barrier island breach and its contributions to lagoonal circulation

Barrier islands are a primary coastal defense and often experience erosion during storms. When they fail due to storm-induced breaching, there can be significant changes the small- large-scale hydrodynamics morphodynamics of region. In this study, we explore formation breach on Hatteras Island, North Carolina, Isabel (2003) subsequent flooding into Pamlico Sound. Two-way coupling high-fidelity, high-resolution numerical models for enables better understanding breach, as well scenarios breach’s effects circulation in The connecting ocean sound formed day landfall. It is shown that, storm, overwash inundation from led deterioration beach dunes, then after creation channels through island was sensitive elevated water levels lagoon. Then considered which ground surface hydrodynamic model (a) static, updated with (b) pre- post-storm observations, dynamically (c) predictions (d) lagoon-side levels. results show that has region-scale extend 10 13 km lagoon, increasing local by much 1 . 5 m These have implications similar island-lagoon systems threatened • A barrier-island predicted models. Ocean-side dune storm. Channel sound-side Erosion coupled assess region scales. Breach allows flows 10–13 increases depths 1.5 m.