Can Sediment Grain Size Be Modeled Using UAV-borne Photogrammetry on an Intertidal Multi-barred Beach?

Sediment grain size is a key parameter in beach morphodynamics. To determine sediment grain size is crucial to better manage and understand the intertidal beach. This study was conducted to determine the potential of UAV-borne photogrammetry to model sediment grain size on a multi-barred intertidal beach. The intertidal morphology of a multi-barred Belgian beach was first represented in a Digital Elevation Model through the use of UAV-borne photogrammetry. Sediment samples were collected uniformly across the beach and analyzed. Grain size was related to the intertidal morphology, in particular with the position and height of the intertidal bars. The first results indicate a higher longshore variability of grain size in the upper intertidal beach. In the lower part of the beach, grain size distribution clearly becomes narrower and shifts to finer sediment. These first results suggest a link between elevation and grain size characteristics. Further analysis will be presented on the correlation of ridge and runnel morphology and grain size. Sediment grain size will be correlated with the cross-shore position of selected sample on the intertidal bars. A relationship will be tested to calculate sediment grain size based on their position on the beach. This analysis will fully assess how UAV-borne photogrammetry can model sediment grain size based on the observed correlations between elevation and position on the beach and sediment type. The use of sediment grain size analysis in simulating and modeling beach dynamics may improve the quality of further models.