Bed load transport model for field conditions – Using characteristic diameter approach

Abstract

A deterministic bed load transport model based on mixed-size (non-uniform) bed material (MBB) has been developed using characteristic particle diameter and published laboratory and field data from the North American and European continents (slope ranges from 0.0023 to 0.047 m/m and bed material size, D50 from 0.033 to 0.106 m) and excess discharge theory. Before developing the model performance of the existing bed load transport models was tested and was generally found to be poor, though discharge based models performed relatively better. In this model fitted values of the relationship exponent ( β) were used instead of considering a fixed value, as in the existing models. Performance of the model was found satisfactory when tested with the field data and compared with another existing model. Subsequently, the model has been extended through the involvement of an active bed width function for non-uniform cross-sectional flow depth (single channel) rivers and for the braided rivers.