Boundary effects on stream meandering and river morphology



ABSTRACT An account of stream meandering and river morphology is given for five experiments, each having different conditions at the wetted perimeter of the channel.

On the basis of the present experiments, it is proposed that a necessary (but insufficient) condition for the formation of stream meandering is an appropriately small ratio of total bank shear force to total bed shear force, both per unit length downstream. In mathematical form, the criterion is expressed by


τs and τs are an average bank stress and bed stress, respectively, and ps and pbb are an average bank wetted perimeter and bed wetted perimeter of a half-channel, respectively. The value of α is evaluated by Kinoshita's (1957) experiment and others.

It is also found that the flow pattern, channel morphology and sand waves on the bed are dependent upon the boundary conditions at the wetted perimeter.