Abstract
Understanding time scales of beach response (erosion and recovery) to extreme storms is particularly relevant for management of coastal land and risk. Observations show that rock-bounded platform beaches are generally remarkably stable and only occasionally respond to extreme storm wave forcing with abrupt morphological changes. The present work aims to understand the conditions leading to the disruption of beach stability (storm thresholds for morphological changes) and to comprehend the conditions of the subsequent recovery.Results obtained at two rock-bounded beaches of the western Portuguese coast over five years provided the foundations of a new conceptual morphodynamic model. This model explains abrupt beach disruption as a consequence of full inundation of the beach profile during extreme storms, together with strong wave reflection at the rigid landward boundary, causing major erosion of the subaerial beach. We argue that the timescale of post-storm recovery depends essentially on the fate of the sediment transported offshore during the storm event. If sediments remain within the beach sediment cell (underwater beach section) beach recovery to pre-storm conditions is very fast, while recovery is much slower if sediments exit the beach sediment cell. In the latter case, beach recovery depends on external sand sources, which can lead to recovery time scales of several years.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.