MATHEMATICAL MODELLING OF SEDIMENT TRANSPORT UNDER TIDAL FLOWS

Abstract

A vertically integrated two-dimensional implicit finite difference cohesive sediment transport model has been developed to study the transport of fine suspended sediments caused by marine works along the east coast of Singapore. Algorithms which describe the transport processes of convection, dispersion, erosion and deposition are incorporated in the model. The suspended sediment concentration computations are made using computed depth-averaged tidal currents and water levels from a compatible nested two-dimensional numerical hydrodynamic model. The hydrodynamics comprising water levels and currents are first verified with measured data collected during a 15-day spring-neap tidal cycle. The suspended sediment concentrations measured at different elevations over the bed during the same period were used as basic data for calibrating the cohesive sediment transport model. The agreement between the simulated and field measured data has been reasonably satisfactory. This is encouraging in view of the lack of field data and the scarce knowledge of the sediment characteristics of the deposits in Singapore coastal waters.