Abstract: Sediment transport and flow resistance are affected by riverbed morphology. As an important aspect of riverbed evolution, effective predictions of bed form changes are practically significant for river regulation and sediment research. This paper determines the characteristic parameters of riverbed forms based on the law of flow resistance. We find an ‘S’-shaped relationship exists between the characteristic parameters of the flow and bed form through analysis of previous experimental data. By automatic division of the bed forms using a SVM multi-classification method, we obtain a fitting function from the nonlinear and linear fittings of dimensionless characteristic parameters, and determine the criterion of riverbed forms through a derivative analysis of the fitting function of characteristic parameters and the sand wave forms. Finally, this criterion is verified against the previous laboratory experimental data and in-situ measurements in literature, showing the method is feasible and quite accurate in riverbed shape recognition.

Key words: river dynamics, riverbed form, resistance law, SVM, morphological parameters