Routing of Heterogeneous Sediments over Movable Bed: Model Verification

A one‐dimensional numerical model of heterogeneous size‐density sediment transport has been developed to simulate the movement of graded sediments in natural and laboratory flow reaches. Predicted temporal and spatial variations in bed and armor‐layer grain size distributions, eroded grain size distribution, eroded thicknesses, and total bedload transport rates compare quite favorably to observed variations in flumes, the San Luis canal, Colorado, and the East Fork River, Wyoming, for a large variety of flow scales and flow conditions. The main advantages of this model over others is the high degree of accuracy of model results obtained using only bed and flow variables as input, the treatment of turbulent fluctuations of bed shear stress, the minimization of calibration factors, and the explicit treatment of multiple grain densities. In addition, only the active layer thickness must be calibrated.