A framework to mitigate aeolian erosion on nourished beaches

Beach nourishment has become a widely adopted nature-based strategy for coastal protection worldwide. However, in regions prone to strong winds, the topographic changes induced by beach nourishment—particularly elevated nourished berms—can significantly alter near-surface wind fields and aeolian sand transport processes. This study integrates field observations with numerical modeling to examine how topographic modifications induced by beach nourishment can influence the coastal aeolian sand transport mechanisms. The key findings are as follows: (1) The elevated beach berms lead to a localized increase in wind speed and a segmented fetch system, with the latter plays a dominant role in limiting the development and transport of aeolian sand streamers; (2) By incorporating the interactions between the transport-stimulated effect of wind intensification and the transport-limited effect of fetch segmentation induced by nourished berm, a “piecewise” model framework was proposed for the aeolian sand transport of nourished beaches, which significantly improving the accuracy of numerical modeling; (3) Based on the improved sand transport model, an optimal beach nourishment design for windy coasts was discussed, and a multi-tiered, mechanically graded berm nourishment approach was recommended to minimize the aeolian sand transport across beach surface.