Modelling of medium scale morphodynamics of a tidal flat area in the German Wadden Sea

Results of the calibration, validation and application of a medium scale process-based morphodynamic model for a tidal flat area in the German Wadden Sea are presented. A time scale of circa ten years and a spatial scale in the order of kilometres have been considered. The depth-averaged model has been set-up with the Delft3D modelling system. It combines validated models for tidal flow, waves and sediment transport. A large amount of measurement data was available for the study area. This led to a thorough understanding of the significant processes and good quality process models. The model has been forced with representative conditions, deducted from long-term observational data. The evaluation of the model has taken place on the basis of qualitative comparison of sedimentation and erosion patterns and a quantitative analysis of the wet volumes of several sub-domains. It is shown that the model is capable of reproducing the medium scale morphological trends rather well. The validated model has been applied to make a ten year prediction of the morphodynamics. Furthermore the location-dependent predominant processes behind the morphodynamics have been investigated.