ABSTRACT
The main thrust of research into sediment transport is towards improvement of numerical modelling methods for coastal sediment transport. The modular method was adopted to allow modification as improvements are made to modelling any of the component parts. Although decoupling is not strictly permissible, it is thought that the errors that result are smaller than the errors in other parts of the model; wave-breaking on sloping beaches on which three-dimensional flow patterns occur is one example; sediment transport is another. The combination of waves and currents is even more difficult, though useful experiments carried out at the Delft Hydraulics Laboratory led to estimation of the coefficients in the Bijker-Frijlink equation. Clearly there is much that is unsatisfactory about the present state of knowledge of sediment transport relationships; although the Bijker-Frijlink equation has been used as an illustration of some of the difficulties, the same problems arise with any other commonly used relationship.
