Effectiveness of Dune Reconstruction and Beach Nourishment to Mitigate Coastal Erosion of the Ebro Delta (Spain)

Abstract

Coastal areas facing increasing erosion are resorting to sand displacement strategies to mitigate the erosive impact, which is exacerbated by climate change. In the face of climate change, coastal managers are more frequently resorting to sand displacement strategies to recover eroding coastlines. These vulnerable coastal zones require innovative approaches to minimize the need for frequent sand replenishment, extend their effectiveness and lower their maintenance expenses. This study undertakes a comparison of four primary nourishment strategies—a conventional uniform nourishment technique and the placement of a single sand dune evaluated at three different positions—in contrast to a scenario where no intervention is carried out. The investigation employs the XBeach numerical model to assess the outcomes of these diverse strategies under both low- and high-energetic storm conditions. The case study is a degraded coastal beach in the Ebro Delta (Spain). The results reveal a significant decrease in erosion when the dune is positioned closest to the shoreline. However, this erosion mitigation effect diminishes as the dune is situated further inland. Conversely, the sand nourishment measure exhibits minimal fluctuations in the volume of eroded sand when compared to the scenario with no intervention.