Development of a 2D depth-averaged model for calculating scouring and deposition in alluvial streams

A depth averaged 2D model is developed to study deposition and scouring in rivers. To calculate the bed load, different empirical formula were implemented. For suspended load, the two-dimensional depth integrated convection-diffusion equation is solved. In this study different widely used empirical relationships were implemented for determining the sediment exchange term with the bed in the suspended load equation. The model was utilized for calculating scouring and deposition in two complicated cases of scouring at a bridge location and scour-hole migration in an erodible channel bed. The results of the model were then compared with experimental measurements as well as 3D numerical model results cited in the literature. Based on these comparisons, the most appropriate combination of empirical formula for sediment exchange coefficient with bed and sediment load to be used for computing scouring and deposition is introduced. The results of numerical simulations show that this model can be used in river engineering for design purposes.