Understanding the present-day morphodynamics of Ameland inlet, part 2

The Kustgenese 2.0 program has resulted in unique high-resolution bed surveys of Ameland inlet. These measurements allow us to (1) investigate, analyse and better understand the morphodynamic changes on its ebb-tidal delta, and (2) to investigate the half-yearly changes in sediment budget. A time series of near yearly ebb-tidal delta bathymetries over the past decade, displays how initial small-scale perturbations in the central part of the ebb-tidal delta (the ebb-chute and shield systems) develop, grow, migrate and start to dominate the developments of the entire ebb-tidal delta. The realisation that small-scale perturbations result in ebb-tidal delta scale relocation of channels and shoals has important implications for the future morphadynamie modelling of the area. These morphodynamic models will have to contain sufficient resolution and detailed processes to capture such distortions. The high-resolution multi-beam data obtained in Ameland inlet provides valuable information on the prevailing sediment transport directions. Such knowledge is essential for the future validation of our process-based sediment transport models. Based on these surveys, we are able to construct sediment transport patterns for the proximal part of the ebb-tidal delta; Borndiep is primarily ebb-dominant and Westgat flood-dominant. These transport directions correspond to the sediment transport patterns derived from the morphodynamic changes. Correspondences in repeat surveys on the ebb-tidal delta confirm that (1) bedform asymmetry is an indicator for bedform migration, and (2) coherent, consistent, bedform fields occur through the various surveys.