Foredune height variations along the western coast of Taiwan Strait

Knowledge of the morphological characteristics of coastal foredunes, particularly crest height, is of crucial importance in evaluating coastal vulnerability to marine disasters. However, the factors driving variation in foredune height and the corresponding mechanisms remain poorly understood, especially for regional, large-scale landscapes. In this contribution, an extensive foredune–beach topographic survey and comprehensive data collection, including regional wind regime, wave and tide climate, were conducted along the ~400 km-long western coast of Taiwan Strait. The results show that the factor with the most significant effect on the spatial variation in foredune height is wave power, followed by aeolian drift potential (shore-normal component), while beach width and grain size appear to have only marginal impacts for our study sites. Under a relatively high-energy wave climate, significant volumes of sandy sediments can be delivered to the beach–dune system, and the beach state tends to be more dissipative, thus contributing to a higher/larger foredune. In particular, the in-phase synchronization of sediment supply (contributed by wave processes) and transport potential (controlled by wind processes) can lead to the greatest potential for foredune growth. Finally, the source (river) to sink (coastal foredune) dispersal of sediments along this ~400 km-long strait coastal regime is summarized.