Abstract Coastal zones need further investigations of beach dune erosion to improve storm‐surge protection measures in light of climate change. This study presents a hybrid approach investigating the influence of coastal foredunes on storm‐induced secondary dune erosion. A data set from 1:7 scaled laboratory flume study was used to calibrate and validate a 1D‐XBeach model. Morphological measurements at various time steps, which included two consecutive storm surges, captured the effects of varying hydrodynamic conditions and foredune configurations, thereby facilitating detailed model application and the identification of uncertainties. Overall, model performance improved over time, demonstrating good to excellent agreement after the foredune evolved into a quasi‐equilibrium profile, while the secondary dune remained in the collision regime (BSS between 0.72 and 0.85 after first storm surge). A temporal delay in foredune transition was observed, which was most evident in case of the high foredune and likely due to the neglect of individual short waves and associated runup. Based on the identified application limitations, the model was employed for a variant study considering additional hydrodynamic conditions and foredune configurations. An increase in water level, significant wave height, and peak wave period each affects secondary dune erosion roughly linearly. The foredune volume was found to be the most significant factor determining the reduction of the secondary dune erosion volume up to an almost complete reduction for non‐flooded foredunes. Furthermore, it was observed that higher significant wave heights lead to increased offshore sediment transport at the foredune, while higher peak wave periods enhance onshore‐directed sediment transport.
Schweiger et al. (Wed,) studied this question.