MODEL FOR PREDICTING DYNAMIC CHANGES IN RIVER MOUTH BAR

摘要

In predicting the topographic changes of the river mouth, the effect of flood currents and that of a gradual shoreward sand transport caused by waves must be taken into account. However, despite large variations, the topography around a river mouth bar and an offshore terrace seems to be dynamically stable in the long term. Taking these points into account, we develop a model for predicting topographic changes as perturbations superimposed on a dynamically stable topography, using the contour line change model. Bathymetric surveys and continuous photographing were conducted at the Sagami River mouth. Then a model for predicting seabed topography around a river mouth under a dynamically stable condition is developed, given a sink and a source of sand, based on the analogy with the potential flow in classical fluid dynamics.