BAROTROPIC PROCESSES OF SEDIMENT TRANSPORT IN TIDAL BASINS: A 1D MODEL FOR THE WADDEN SEA

摘要

Morphodynamic research is crucial for preserving the Wadden Sea’s unique environment. Its morphological evolution is governed by several sediment transport mechanisms, but a ranking of their relative long-term impact has not yet been established. 3D process-based models are not feasible for such purpose, while idealized models suffer from oversimplifications. In order to bridge the two, we propose an intermediate approach that is particularly suited to investigate the barotropic mechanisms recognized in literature as possibly dominant. The residual fluxes of non-cohesive sediment in the Vlie basin are simulated over a semidiurnal timescale. Different conditions are mimicked by varying settling velocities and critical bed-shear stresses. Results suggest a possible state of grain-size-selective residual transport, on which the bed resistance to erosion has only little influence. Under an average wind condition, tidal asymmetry is recognized as the main sediment transport mechanism.