Bar Migrations on a Macrotidal Ebb Delta over a Period of Six Years Using Lidar Survey

Xavier Pellerin Le Bas (1) , Franck Levoy (2)

1 M2C - Morphodynamique Continentale et Côtière
2 CREC - Centre de recherches en environnement côtier

The migration rates of two swash bars on an ebb delta are studied in a macrotidal environment. A dataset of 12 LiDAR surveys, from 2011 to 2017 is used to compute the movement of the swash bar crests using Digital Shoreline Analysis System (DSAS) version 4.3. Hydrodynamic data are acquired near the ebb-tidal delta during the same period. The relationship between bar migration rate and wave energy flux is analyzed. The correlation is high (r2 = 0.71), but a specific migration rate of the two bars weaken this result. Furthermore, the two swash bars have two different behaviors under the same hydrodynamic conditions. Other analyses are conducted concerning the relationships between the migration of the bar and its volume or the water depth. The correlations are too weak to explain the different behaviors of the bars. Another parameter is highlighted, the number of swash bars in the immediate vicinity of the two bars.

Mots clés: Macrotidal environment; LiDAR surveys; Swash Bar; Ebb-Tidal Delta

Domaines: Sciences de la Terre; Géomorphologie

Xavier Pellerin Le Bas, Franck Levoy. Bar Migrations on a Macrotidal Ebb Delta over a Period of Six Years Using Lidar Survey. Journal of Coastal Research, 2018, 85, pp.146-150. ⟨10.2112/SI85-030.1⟩. ⟨hal-01983333⟩