Effect of rigid vegetation on velocity distribution and bed topography in a meandering river with a sloping bank

In the present study, a physical model of a meandering river with the sloping bank was used to assess the effects of rigid vegetation on flow velocity distribution and bed scouring at the toe and bank slope of a meandering river. The experimental tests were carried out under non-vegetated condition as a reference and vegetated conditions with six different patterns. The results revealed that the flow velocity distribution and bed topography at each cross-section were considerably affected by vegetation density and planting patterns. For the vegetated condition, the longitudinal flow velocity component increased in the main channel, while it decreased in the bank zone when compared to the non-vegetated conditions. Additionally, in the presence of vegetation, the core of maximum velocity diverts toward the centerline of the flume, which reduces erosion risk. Furthermore, a comparison of the longitudinal velocity profiles under vegetated and non-vegetated conditions showed that the area occupied by the core of maximum velocity at the bend apex decreases up to 26%, notably for the conditions with double rows and hybrid patterns. The results of this study showed that the use of vegetation can be recommended to stabilize rivers’ bed and banks a green and cost-effective alternative to hard-engineering methods.