STUDY ON NUMERICAL SIMULATION AND FACTOR ANALYSIS OF FLUSHING RIVER MOUTH BAR

Abstract

A 2D River morphology model with a curvilinear grid is developed to simulate the flushing river mouth bar occurred at the Ara River in July 2004. In the hydrodynamic model, the 2D free surface flow is calculated by the Saint Venant equations which are solved by an implicit finite difference technique and the ADI method. In the morphological model, the Van Rijin's model is used to evaluate sediment transport including bed load and suspended load. The helical flow and the transverse bed slope modify the bed load sediment transport. The bed level change is computed by a sediment continuity equation of the bank erosion model. The model is validated by comparison with the observations of water level variations and the riverbed topography at the mouth. A factor analysis is conducted to evaluate the effects of discharge, tide level, and grain size. The result shows that differences of sea elevation and peak discharge have significant effects on a process of morphological change at the river mouth.