Effects of Floodplain Vegetation on Momentum Transfer in Compound Channel

Abstract

Better management of riparian vegetation for flood control and environmental preservation requires in-depth understanding of flow characteristics in the presence of vegetation. This study aims at clarifying the flow structure and lateral momentum transfer process in vegetated compound channels through experiments and numerical simulations. Two types of vegetation zone on a floodplain are discussed. In the first case a floodplain is fully covered by vegetation. In the other case a floodplain has a belt of vegetation zone along the interface between main channel and floodplain. The measured data are compared with the numerical results that are obtained using a non-linear k-ε model and a vegetation model. It is found that the numerical model can reproduce the main characteristics of the flow and that the convection and the turbulent diffusion play important roles in the lateral momentum transfer across the interface between vegetated floodplain and main channel.