Flow and sediment transport in emerging vegetated zone

Vegetation on the streambed increases the total resistance but decreases the bed shear stress. However, when the drag force term is not separated from the resistance term in the momentum equation, increasing the roughness coefficient due to vegetation may result in increasing the bed shear stress. This is not realistic and crucial to the accurate assessment of sediment transported in the vegetated zone. This paper presents a ID model for the simulation of flow and sediment transport in the emerging vegetated zone. The model consists of depth-averaged equations of continuity, momentum, turbulent kinetic energy, and its dissipation rate. The suspended load and bedload are estimated, and the bed elevation change is computed by solving the Exner's equation. The model is validated through comparisons with experimental observations. Then, the model is applied to predict the morphological change of the emerging vegetated zone in response to the flood. The developed model can be used to the management of vegetated islands within watercourse made naturally which are important to river restoration projects nowadays.