Causes of the different behaviour against erosion: Study case of the Benidorm Beaches (1956–2021)

Coastal erosion is a natural phenomenon that is becoming a growing problem along coastlines around the world. In this research, the evolution of two beaches located in Benidorm (Spain) has been studied: Poniente Beach and Levante Beach. Both have similar characteristics, but present a different morphological behaviour. An analysis of shoreline evolution has been carried out using aerial images. Then, waves and incident storms were studied and, finally, a sedimentological analysis was performed. From the results obtained, the eastern zone of Poniente Beach presents higher rates of erosion than the western zone. This erosion trend disappeared in the last analysed period due to a change in the incoming wave regime. A decrease in the frequency of waves coming from the east caused the erosion and tilting suffered by this beach. In Levante Beach, the intensity of the waves was reduced, making erosion rates lower. Furthermore, important differences were found from the sedimentological study, such as the lack of homogeneity in sediment grain sizes and a worse wear behaviour on Poniente Beach compared to Levante Beach, which means that these two beaches behave differently facing erosion. This accurate knowledge of the factors mentioned will provide adequate tools for its future management.