Abstract
A one dimensional model to predict the long term stability of channel bed elevation and grain size profile is proposed. The model is tested using the geometric conditions of the Ishikari River. By a series of calculations using different discharge profiles, it is shown that the two different characteristics of grain size distribution, with and without an abrupt change in the longitudinal direction, can be formed simply by changing the discharge scale. It is also shown that the formation of the bed elevation profile as well as the grain size profile can be calculated using time series of actual discharges over a wide range of magnitude.
