|Wave effects on the morphodynamic evolution of an offshore sand bank|
Giardino, A.; Van den Eynde, D.; Monbaliu, J. (2010). Wave effects on the morphodynamic evolution of an offshore sand bank. J. Coast. Res. SI 51: 127-140
In: Journal of Coastal Research. Coastal Education and Research Foundation: Fort Lauderdale, Fla., USA. ISSN 0749-0208, more
sand bank; waves; morphodynamic evolution; numerical models; wave climate; bed form asymmetry
The origin and morphodynamic evolution of linear sand banks have been widely studied in recent years. Several investigations have been carried out in order to understand the influence of tide-related parameters, bathymetry and Coriolis force on sand bank formation and maintenance. However, the effect of waves on the net flux of sediments over the sand banks has often been neglected on grounds of the short duration of significant wave activity compared to that of tidal cycles. Nevertheless, the interaction between wave activity and tidal currents leads to a high increase of bottom shear stress, especially at the sand bank crests and, as a consequence, to an increase of sand tranport. This paper investigates the effects of wave activity on the morphology and morphodynamics of the Kwinte Bank (Belgian shelf). Numerical simulations were carried out under different wave conditions to assess wave influence on sand bank evolution. Model verification involved analysis and comparison with field data collected during two different periods. The study shows that wave activity is not only responsible for a large increase in sediment transport but also for a change in direction of the net flux of sediments. Moreover, the morphological analysis of several sand banks supports the idea that wave activity might also have an impact on the shape of these sand banks. Wave climate data can be used to study long-term sand bank dynamics.