Influence of Belowground Biomass on Barrier-Island Evolution During Storms: A Computational Parameter Study

Barrier islands span 10% of the world’s coastlines and dominate along the Atlantic and Gulf of Mexico coasts in the USA routinely exposed to storm surge. These islands serve as buffers between the open coast and the mainland, and protect the mainland from storm damage. During storms, significant morphological change can occur, including substantial erosion of the islands’ vegetated dunes. In this study, the focus is on the influence of belowground biomass – namely dune plant roots – and dune topographic characteristics on barrier-island erosion during storms. The numerical model XBeach was employed to simulate storm-induced sediment transport. A parameter study was conducted by varying distance from the shoreline to the dune, dune shape, sediment grain size, and sediment mobility as an analogue for biomass. The influence of individual parameters and the collective impact of parameters were analyzed. The results help improve our knowledge of barrier island dynamics and lay a solid groundwork for future investigations.