Coastal Dunes Mobility Integration and Characterization: Developing of a Flexible Volume Computing Method

Abstract

Coastal dunes are among the most complex interfaces to study in the world. Improving the knowledge of their morphodynamics is essential to better understand the present evolutions and try to anticipate future. The recent use of the new vectors that are drones, UAV and UAS, improves the temporal and spatial resolutions of geomatic data acquired on these environments. Many studies attempt to measure the sedimentary variations that occur from one date to another by the use of differential volumes. In particular, they make it possible to understand the roles of storms, sometimes erosive, as well as the possible morphological responses of associated reconstruction periods. One of the primary methods for calculating volume evolutions is the assessment of a vertical delimitation of the dune toe. However, it is difficult to limit mobile and variable environment, temporally and spatially, to a simple vertical topographic delimitation. This study was realized to estimate the error induced by the use of the vertical threshold method. In the examples that were done, this error was far from being negligible and might in some cases exceed the evolutions of measured volumes. In overcoming this problem, an alternative method was developed. It was the seemingly better adaptability to these mobile environments that are the coastal dunes.