Climate Change Impacts on Coastal Wave Dynamics at Vougot Beach, France

Abstract

Wave dynamics contribute significantly to coastal hazards and were thus investigated at Vougot Beach by simulating both historical and projected future waves considering climate change impacts. The historical period included a major storm event. This period was projected to the future using three globally averaged sea level rise (SLR) scenarios for 2100, and combined SLR and wave climate scenarios for A1B, A2, and B1 emissions paths of the IPCC. The B1 wave climate predicts an increase in the occurrence of storm events. The simulated waves in all scenarios showed larger relative changes at the beach than in the nearshore area. The maximum increase of wave energy for the combined SLR and wave scenarios was 95%, while only 50% for the SLR-only scenarios. The effective bed shear stress from waves and currents showed different spatial variability than that of the wave height, emphasizing the importance of interactions between nearshore waves and currents. Increases in the effective bed shear stress (combined scenarios: up to 190%, and SLR-only scenarios: 35%) indicate that the changes in waves and currents will likely have significant impacts on the nearshore sediment transport. This work emphasizes that combined SLR and future wave climate scenarios need to be used to evaluate future changes in local hydrodynamics and their impacts. These results provide preliminary insights into potential future wave dynamics at Vougot Beach under different climate change scenarios. Further studies are necessary to generalize the results by investigating the wave dynamics during storm events with different hydrodynamical conditions and to evaluate potential changes in sediment transport and morphological evolution due to climate change.

Morphodynamic Evolution and Sustainable Development of Coastal Systems

“…Climate change impacts on coastal-scale wave dynamics were investigated by Dissanayake et al [6] applying the Delft3D modelling suite at Vougot Beach, France. Simulations were carried out using a measured historical wave time series, which was then projected into the future.…”

“…Analyses of field data for morphodynamic evolution [1][2][3]; • Sustainable development for coastal protection [4,5]; • Numerical modelling of hydro-morphodynamic processes [6][7][8][9][10];…”

Tidal influence on the littoral drift of a beach with complex bathymetry: example of the Vougot beach, Guissény (France)

“…The beach/dune system faces a 3 to 6 km wide platform in the coastal zone with reefs and islets (figure 1b). These features create complex nearshore topo-bathymetry that strongly influences the local hydrodynamics (i.e., wave and currents) (SUANEZ et al, 2012;DISSANAYAKE et al, 2021). The macrotidal range reaches 8.4 m for astronomic tides, and the intertidal beach surface can extend over 400 m at low tide.…”

“…The aim of this study is to improve the understanding of hydro-morphodynamic processes in complex coastal environments, in order to understand better the observed morphodynamics. This understanding is necessary to improve models of coastline evolution that reproduce the observed changes and predict future change scenarios, in particular in response to climate change (DISSANAYAKE et al, 2021). The experimental site is the beach of Vougot in Brittany (France, Figure 1), at which topomorphological monitoring (monthly beach profiles including the intertidal zone and the dune) has been carried out for more than 17 years.…”

“…These morphosedimentary changes suggest longshore sediment transport linked to the littoral drift, oriented from east to west (e.g. CHATAIGNER et al, 2019;CHATAIGNER et al, 2020;DISSANAYAKE et al, 2021). To test this hypothesis, in situ measurements of nearshore wave height and direction, as well as currents (cross-shore and longshore), in the intertidal zone as well as offshore of the beach (up to 35 m depth), were made with current meters, pressure sensors and imagery acquired by a drone.…”