Problems in measuring bed load discharge considering the discrete nature of its movement

During the experiments, under various flow conditions, bed reliefs were created, on which dunes and waves of two additional levels were identified. The fundamental difference between dunes, which are forms of bed load movement involving mass transport, and waves, which represent the interface between moving dunes and the underlying bottom sediments, is defined and substantiated. A comparison of bed load discharge measured by the reference (volumetric) method directly in the flume with that calculated based on dune and wave parameters shows that the discharge calculated from dune parameters is closest to the reference. However, summing the bed load discharge obtained from the parameters of dunes and waves at other levels leads to a significant overestimation of the total discharge by an average of 66 %. Furthermore, the article presents results comparing the geometric parameters of dunes and waves and substantiates the conclusion that only the dune form of bed load movement should be considered when calculating flow rates, and that wave height should be considered when calculating guaranteed depths for dredged channel design.