Comparing 2D models in simulating suspended sediment processes in vegetated flow

Baptist’s method, Drag Force and Single-Stem approaches are the commonly used tools implemented in Delft3D to model water and sediment transport processes in vegetated channels. Despite their wide application, the model reliability has seldom been tested against data of controlled flume experiments with solid suspension. Here, we investigate the ability to reproduce suspended sediment transport through emergent vegetation by comparing the results of 2D simulations to existing experimental data. The results show that in low vegetation density, the Baptist and Drag Force approaches are not sensitive enough to density variations. The Single-Stem approach reproduces detailed flow structure and sediment deposition around stems, but its high computational time is a limitation for long-term simulations or dense vegetation. Furthermore, we observed that the simplification of 2D depth-averaged models and the non-equilibrium of sediment transport in both experiments and numerical simulations may also affect the overall performance of the vegetated modelling approaches.