Study on the Pollutant Diffusion Regularity in Open Channel with Vegetation

Instream vegetation not only affects the discharge capacity of the river but also plays an important role in the pollutants diffusion. So it is very important to study the pollutants diffusion in the open channels with vegetation. In order to experimentally investigate the effects of rigid vegetation on the characteristics of flow, the vegetation was modelled by a rigid cylindrical rod. The flow field is measured under the conditions of submerged rigid rod in a flume with single layer and double layer vegetation. Experiments were performed for various spacing of the rigid rods. The vegetation models were aligned with the approaching flow in a rectangular channel. Vertical distribution of pollutants was evaluated using image processing methods. The results indicate that the vegetation has a more stable effect on the spread of pollutants.