The oft-cited Coastal Dune Model (CDM) predicts that dune height is controlled by negative feedback between wind flow and topography and that the beach-dune profile is scale invariant. To test the scale-invariant result of the CDM, Lunardi et al. quantified the inter- and intra-site variability of the beach-dune morphology using a combination of LiDAR and UAV surveys of more than 19,000 beach-dune profiles along the north shore of Prince Edward Island (PEI). Contrary to the predictions of the CDM, the authors found that the profile morphology was inversely related to the cross-shore distance between the vegetation and the shoreline. The beach-dune morphology along the north-shore of PEI results from the local history of storm erosion and recovery and not a dynamic feature that develops from the negative feedback assumed in the CDM.
The results of Lunardi et al. are consistent with beach-dune profiles extracted from previously published studies, suggesting that the site-specific morphology of coastal barriers is global. While it is possible that the CDM is appropriate for the initial formation of a coastal dune under idealized conditions, it should not be used to evolve the system and in the prediction of barrier transgression. Understanding how coastal barriers will evolve with rising sea levels and changes in storm activity requires additional field studies focused on the inter- and intra-site variability of beach-dune morphology and interaction.
Acknowledgments. This study was funded by a Natural Sciences and Engineering Research Council (NSERC) of Canada grant. In-kind support and access to the study site was provided by Prince Edward Island National Park (PEINP) and Parks Canada.
Citation: Lunardi, B., Smith, A., George, E., Lehner, J., and Houser, C. (2023). Intra- and Inter-site variability of the beach dune profile and vegetation line: Is there a scale-invariant profile? Geomorphology.