Laboratory experiments in a mildly sinuous channel with bank vegetation

Vegetation is a common feature of most natural rivers and is widely used for rehabilitation. Consequently there is a need to better understand how vegetation effects the interaction of flow, sediment and channel boundaries. In this paper we examine the effect of bank vegetation on the flow structure of a physical model of a natural river with large radius bends. 2D ADV measurements are recorded under three different configurations; bare, partially vegetated and fully vegetated banks. Without vegetation, it was found that flow largely resembled that in a meander bend. After placing vegetation along the outside bank, flow was more symmetrical and a shear layer and different secondary currents emerged in the near bank zone. In regards to rehabilitation, full coverage was most effective in reducing shear stress, but it is suggested that partial coverage is almost as effective and a good alternative in revegetation projects with limited resources