DWSM: a sixth-generation 3D model of the Dutch Wadden Sea : 2022 release

The development of this model is part of a more comprehensive project in which sixth-generation models have been developed for all waters maintained by RWS. An important difference with the previous fifth-generation models is the use of the D-HYDRO Suite (known internationally as the Delft3D Flexible Mesh Suite), the new software framework for modelling free surface flows, which was first released in 2015 and allows for the use of unstructured grids. During the initial Dutch Wadden Sea Model (DWSM) model development, use was made of preliminary versions of the larger domain Dutch Continental Shelf Models (DCSM-FM 100m and 3D DCSM-FM). Since these model schematizations were further developed and later officially submitted to Rijkswaterstaat, it was asked to assess the impact of these further developments on the DWSM model. This made clear that several improvements needed to be included in a new, second release of DWSM. Within KPP Modelschematisaties 2022 this new hydrodynamics-only release was developed and validated. The model was updated with respect to model bathymetry, tidal boundary forcing, meteorological forcing and numerous other adjustments and improvements. The present report deals with the model description of this second release, including the validation results. For external reference purposes, the name dflowfm3d-waddenzee_200m-j22_6-v1a is used for this model.