Prediction of the bedload transport rate in vegetated rivers based on turbulent kinetic energy

ABSTRACT Aquatic vegetated habitats are disappearing rapidly, and restoration projects are crucial for maintaining their ecological functions. The success of these projects hinges on the ability to retain sediment, necessitating a comprehensive understanding of sediment transport in vegetated areas. Therefore, this study builds a model based on the flow turbulent kinetic energy near the riverbed to predict bedload transport. The turbulent kinetic energy in the model comprises turbulent terms generated by the riverbed and vegetation, which can be further divided into a shear turbulent term induced by the velocity difference and a stem turbulent term induced by the vegetation stem. The experimental data confirmed that turbulent kinetic energy can predict the bedload transport rate more effectively than bed shear stress. The average relative error of the predicted bedload transport based on bed shear stress was within 632%, and the average relative error of the predicted value based on turbulent kinetic energy was within 97%. When the dimensionless submerged vegetation density was less than a threshold, the bedload transport rate increased with increasing vegetation density. These findings yield crucial insights into the interaction mechanisms among vegetation, flow, and sediment and provide a promising direction for predicting sediment transport in the future.