The Influence of the River Bank Covered Partially with Vegetation on Flow Characteristics

The aquatic vegetation is an important part of the river ecosystem. The present paper studies the flow characteristics in the influence of bank vegetation. A two-dimensional mathematical model is developed to simulate the flows under the influence of vegetation based on the Godunov finite volume method. The resistance term caused by different vegetation types is included in the momentum equations as a sink term. The proposed numerical model was used to simulate the flume experiments in partially vegetated channels. Numerical results are compared with the experimental data, which shows suitable agreement. Using the developed numerical model, the effect of vegetation on the water level and flow velocity in the Fuhegudao River, a natural ecological river, is studied. The results show that the existence of the vegetation in the upstream bank makes the upstream water level rise obviously, the flow velocity of the main channel decrease, the risk of the flood overflow in the upstream reaches increase, and the flow velocity in the flood plains increase.