Grain size dependency in sandbank modeling for the case of uniform sediment

A 2-D depth-integrated stability analysis designed for marine tidal sandbanks is developed to investigate the relative influence of the grain size–dependent parameters on the simulated dynamics of the sandbanks for the case of uniform sediment. The model is applied to a real case in the North Sea. Assuming that the model is valid mainly in an area where bed load is the dominant sediment transport mode, the model taking into account the grain size dependencies gives a better prediction of sandbank occurrence than models neglecting these dependencies. All the grain size–dependent parameters are investigated separately. Focusing on the morphological time and wavelength of the sandbanks, this paper demonstrates that neglecting the grain size dependencies, especially the transport threshold, has a drastic influence on the dynamics of modeled sandbanks, especially on the sandbanks growth rate. The influence on the geometrical properties (wavelength and orientation) is less pronounced.