Improving wave-driven cross-shore sand transport modelling in Delft3D
using the new SANTOSS transport formula
Roelof Veen, University of Twente, r.veen-1@student.utwente.nl Jebbe van der Werf, Deltares, jebbe.vanderwerf@deltares.nl Jan Ribberink, University of Twente, J.S.Ribberink@utwente.nl Joep van der Zanden, University of Twente, j.vanderzanden@utwente.nl
Morphological modelling systems like Delft3D are used to understand coastal morphodynamic and predict erosion and sedimentation. These models are important tools for coastal managers, for example for harbor design and nourishments. This study aims to assess and improve the way Delft3D models wave-driven cross-shore sand transport by implementing and testing the recently developed SANTOSS (Van der A et al., 2013) near bed transport model.
For implementation, the SANTOSS model is extended so it could be applied to coastal conditions. The first addition was to determine sand transport in current dominant flow. The second addition was adding a method to determine the wave velocity and acceleration skewness. The third was applying a longitudinal slope effect to the critical shear stress for the calculation of sand transport on slopes. The near bed transport of the SANTOSS model in Delft3D is combined with the current related suspended sediment transport of Van Rijn (2007).
The Delft3D assessment was done by modelling an erosive and accretive case of the LIP experiments (Roelvink and Reniers, 1995). The results of the near bed transport modelled with the new SANTOSS model are promising for the accretive case as the new model preforms better than the current state-of-the-art Van Rijn (2007) transport model (Figure 1). For the erosive case, the SANTOSS model preforms better than Van Rijn (2007) offshore but worse onshore of the breaker bar.
