A graded sediment transport and bed evolution model in estuarine basins and its application to the Yellow River Delta

Details are given in present paper of the development of a sediment transport and morphological model to predict the bed evolution processes in tidal flows. The model is based on an existing hydrodynamic and sediment transport model (DIVASTSED), but with significant refinements being made. A single size sediment transport module is refined to include capability for simulating the transport of graded sediments under non-equilibrium conditions. Both cohesive sediment and non-cohesive sediment are taken into consideration in present study. The fall velocity of suspended sediment is modified in present model due to the high sediment concentration. A 3-layer approach is adopted to simulate the variations of sediment gradations of bed materials. The model is used to simulate the bed evolution in the Yellow River Delta from 1992 to 1995, the numerical results show how the morphology developed in the Yellow River Delta and agree well with the field data. The present model could provide an effective tool for the management of wetland in the Yellow River Delta.