Modeling of River Channel Changes

Abstract

A computer‐based flood‐ and sediment‐routing model which simulates river channel changes is described together with its application in the case study of a disturbed river. Simulated results of this study are supported by field observations and measurements. This model incorporates the interrelated changes in channel bed profile, width, and lateral migration in channel bends. These changes reflect, in part, a river's adjustments in power expenditure. The interrelation of changes in channel bed profile and width is illustrated by a physical example and explained by the river's tendency to establish equal power expenditure along the channel. Such power transformation associated with river channel evolution tends to restore the dynamic equilibrium in sediment transport, that is, equal sediment load along the channel. The case study demonstrates that in the case of severely disturbed rivers, flood‐level computation using a fixed‐bed model may be quite inaccurate and improved accuracy can be provided by an erodible‐bed model.