Long, Medium, and Short-term Shoreline Dynamics of the Brittany Coast (Western France)

A long-term dataset of topography and nearshore bathymetry at the macrotidal pocket beach of Porsmilin, France

“…1a,b ). This jagged coastline chosen by Mandelbrot to illustrate fractals in nature 43 is essentially rocky and contains beaches of moderate size (42% are shorter than 200 m and only 12% are longer than one km, based on a sample of 600 beaches 38 , 44 ), often characterised by moderately to highly indented planform geometries.…”

“…1b,d ). Yet, due to a prominent continental shelf with numerous islands and reefs, which affect wave propagation, wave exposure at the coast is very heterogeneous 38 . The wave climate also exhibits strong seasonal change in wave energy.…”

“…Field data collected at Porsmilin have been used to investigate the morphodynamic response of macrotidal embayed beaches 31 , 35 , equilibrium modelling of the beach profile 36 , and the conditions controlling beach cusps development 37 . They also contributed to a regional assessment of the shoreline dynamics of the Brittany coast 38 , and erosion and recovery following extreme storm activity during the 2013–2014 winter at both local 39 and European scales 33 , 34 . Other studies interested in the methods for collecting and processing these geomorphic data present detailed information and validation of the techniques implemented in the survey program 40 – 42 .…”

Systemic vulnerability of coastal territories to erosion and marine flooding: A conceptual and methodological approach applied to Brittany (France)

“…So, from a geomorphological perspective, the Brittany coastline appears to be relatively less exposed to coastal hazards than other French coasts: tectonically stable crystalline basement and few extensive low-lying areas. However, 35% of its beaches have been showing a tendency for coastal erosion since the 1950s [95]. Moreover, since the 19th century, the old maritime marshes were drained for agricultural purposes before they were urbanised in the second half of the 20th century.…”

“…In the Hazards component, data are extracted from reference datasets: the National coastal erosion indicator (INEC), and the low-lying coastal areas, both available in the Geolittoral Spatial data infrastructure iv . In most exposed areas, surveys are conducted on reference points, along transects, or on coastline segments of homogeneous geomorphology [95]. These surveys are eventually carried out by the local authorities involved in the partnership.…”