The influence of washover dimensions and beach characteristics on the sediment transport during inundation

Barrier islands need sediment input to keep up with sea-level rise. Landward directed sediment transport during storminduced inundation can contribute to the vertical accretion of barrier islands and therefore, the partial re-opening of the artificial sand-drift dikes is considered for the Wadden Islands in the Netherlands. This XBeach model study investigates the role of the washover width and height, and the beach width and slope on the hydrodynamics and sediment transport at the washover opening during inundation. Simulations show that the washover height is the most dominant factor. Lower washover heights result in more sediment transport. Furthermore, for wider openings the total sediment transport through the entire opening firstly increases rapidly and then increases more gradually. The beach width and slope are expected to have limited effect on the sediment transport at the washover opening.