The influence of leafy vegetation on flow hydrodynamics and sediment transport

Investigating the intricate interplay among flow dynamics, sediment pro cesses, and vegetation is crucial for improving predictions regarding morphological evolution in rivers. This study focuses into the combined influence of large-scale bedforms (3D dunes) and leafy flexible vegetation on flow characteristics. Laboratory experiments were carried out under both mobile-bed and fixed-bed conditions. The fixed bed conditions were represented by the final topography resulting from the mobile-bed experiments that was obtained by means of the Structure-from-Motion technique. Comparisons between the two bed conditions reveal significant disparities in velocity profiles and turbulence characteristics. The presence of leafy vegetation is found to enhance bed-load transport, challenging previous claims about the role of vegetation in suppressing sediment transport. These findings highlight the limitations of simplistic models, particularly in representing vegetation and bedforms, while also aiding in the refinement of sediment transport models in natural river systems.