Wave attenuation and Coastal Protection by Shelly Ridges: Mont-Saint-Michel Bay, France

Shelly ridges in Mont-Saint-Michel Bay, France, demonstrate remarkable wave attenuation capabilities, reducing energy by 92% to 98% as waves traverse well-formed systems. This significant dissipation, primarily affecting wind-wave and swell energy while leaving infragravity frequencies dominant, highlights their role in coastal protection. In contrast, degraded or breached ridges show reduced attenuation (70% to 90%), with a mix of gravity and infragravity energy. The study employed monthly topographic surveys using DGPS and hydrodynamic measurements via miniature pressure sensors deployed since February 2015, providing preliminary evidence that shelly ridges mitigate wave impact on shorelines. Further research under stronger wave conditions is needed to solidify these findings.

Jeanson, M., Etienne, S., & Collin, A. (2016). Wave attenuation and Coastal Protection by Shelly Ridges: Mont-Saint-Michel Bay, France. Journal of Coastal Research, 75(sp1), 398–402. https://doi.org/10.2112/si75-080.1