An agile IHCantabria model anticipates how beaches rotate over time

IHCantabria leads a study that anticipates the orientation of beaches in very diverse environments, thanks to an agile and innovative coastal model.

A team of researchers, coordinated by the Environmental Hydraulics Institute of the Universidad de Cantabria (IHCantabria) has validated an innovative coastal model, capable of anticipating how the orientation of the coastline varies in beaches with very different morphological characteristics. The results of this work demonstrate the versatility and speed of the equilibrium-tending shoreline orientation evolution model when applied to scenarios as diverse as a high-energy beach in Australia, a highly urbanized cove in Mallorca, or a coastline with extreme tides in the United Kingdom.

The study was led by predoctoral researcher Mayowa Basit Abdulsalam (Université de Rouen, France), who is the first author of the scientific paper entitled “Assessing shoreline orientation variation across diverse coastal environments.) ─published recently in the journal Coastal Engineering─, to which researchers from IHCantabria -CamiloJaramillo, Lucas de Freitas and Mauricio González-and Professor José A.Á. Antolínez, from Delft University of Technology (TU Delft), The Netherlands, contributed as co-authors.

How was the study conducted?

The rotation model used was proposed more than four years ago by a team of researchers from IHCantabria ─Camilo Jaramillo, Mauricio González and Raúl Medina─and Imen Turki, from the University of Rouen, France. This model is able to reproduce both short- and medium-term beach turnover patterns without the need for complex simulations. Until now, shore orientation evolution models of this type had been tested, almost exclusively, on low-tide (micromareal) beaches and with very homogeneous data. The results of the study referred to in the article recently published in the journal Coastal Engineering break that limit, as it demonstrates that this innovative model is able to anticipate how shoreline orientation varies on beaches that have significant differences in grain size, incident wave patterns, tidal regime and frequency of monitoring of their coastal data.

To test the selected rotation model, the research team selected seven embedded beaches in four countries: Narrabeen-Collaroy Beach (Australia), Tairua Beach (New Zealand), Blackpool Beach (UK) and Playas de Poniente, Levante and Cala Millor (Spain). The team processed time series of waves with daily, seasonal and annual resolutions; they also evaluated their effects at different intertidal heights. Through a sensitivity analysis, the influence of the mean incident energy flux -determined by the predominant wave direction and wave intensity- on the shoreline configuration was quantified. This approach allowed validating the model under varied natural conditions and detecting its limits in highly dynamic contexts.

This study arose from the master thesis developed by Mayowa Basit Abdulsalam within the Erasmus Mundus COASTHazar Master program and is framed within the Shoreline Evolution Tools (IH-SET) project of the Marine Science Program of IHCantabria. The source code of the model is available on GitHub.

Results of the study

The results of this international study demonstrate that the application of the model previously proposed by IHCantabria’s research staff allows predicting with high reliability the short and medium term rotation patterns of the coastline in a variety of environments. The model accurately reproduced both seasonal changes and interannual variations in the orientation of the coastline in the cases analyzed. The researchers emphasize that the quality of the predictions depends critically on having wave and shoreline position data with adequate temporal resolution.

Relevance and impact of the model

“Having a fast and adaptable tool to anticipate the orientation of the coast is essential to design adaptation strategies, mitigate erosion risks and plan the coast,” explains Camilo Jaramillo, researcher at IHCantabria. The model used is an accessible resource for coastal managers, as it can be easily integrated into early warning systems and climate scenario simulations. In addition, it optimizes decision-making in the planning of erosion mitigation measures and the design of coastal works, thus reducing the vulnerability of coastal communities to climate change.

The full content of the article can be accessed through the following link: https://www.sciencedirect.com/science/article/pii/S0378383925000754?via%3Dihub

Landscapes of some of the beaches that were selected to test the selected rotation model. From left to right: Cala Millor beach (Spain) and Narrabeen-Collaroy beach (Australia)