Abstract:A depth-averaged finite difference two-dimensional hydrodynamic-morphological and sediment transport model is presented in the orthogonal curvilinear grid system. Based on the previous work

the influence of selective sorting is taken into account in the sediment model by modifying the sediment transport capacity; the grain size distribution is simulated according to the sediment mass conversation equation for bed surface. The model is applied to the experiment on downstream fining by seal. The simulated bed profile and grain size distributions are in acceptable agreement with the field measurements. It illustrates the capability of the two dimensional models in predicting the river morphology and grain sorting processes for actual rivers.