Experimental Study On Flow Velocity Characteristics And Pollutant Transport In Vegetation Channel

With the rapid development of economy, more and more types of pollutants aredischarged into the nature by human. Water resources are destroyed and human life isalso threatened. As we know, water resource is very important for human survival.Protection and rational use of water resources and take the road of sustainabledevelopment are the focus of contemporary research scientists. The river is thetransmission tool and an important carrier of water resources. Reasonable planningand management should be applied to the management of the river to improve theutilization efficiency of water resources and avoid the waste of water resources.Recently, construction of ecological civilization has been given much focus bythe people. The communist party’s18thnational congress put forward a strategicdecision that we should promote the construction of ecological civilization from newhistoric starting point. The construction of ecological river offers a new effective andecological environmental method for river management and planning. Riparianvegetation can conserve soil and water and purify water quality, it also has goodrepair for the ecological system. However, vegetation will recede the watercourse’scapability of flood discharge. There are a lot of aquatic plants in natural channel. So,to further study the effect of plants on the flow has important practical significance forthe construction of environmental protection and ecological civilization.The experiments were conducted on a rectangular flume. And PVC cylindricalrods are simulated as rigid vegetation and rubber rods are simulated as flexiblevegetation. A propeller current meter was used to measure the instantaneous flow fieldunder the different location and flow. The paper mainly studies three aspects asfollows:(1)This paper analyzes the velocity variation of flow in rigid vegetation channel.And the figure of velocity distribution and velocity variation along the river in thearea of vegetation and non-vegetation under the different conditions are shown in thepaper. And a two-layer model is established to predict the velocity distribution in therigid vegetation channel in submerged state.(2)This paper studies the effects of flexible vegetation on the flow velocity fromtwo perspectives of velocity of the section center along the river and the comparison of velocity of different section in vegetation area.(3)In natural river environment, the heights of different kinds of plants aredifferent. To simulate this environment, two different heights of rods are simulated asvegetation. This paper analyzes the effects of two different heights of rods on flowvelocity. And the figure of velocity distribution spots of vertical lines and the typicalvelocity distribution are shown. Finally, some conclusions are draw from the analysis.(4)In the study of the effects of vegetation on the pollutant transport, Rhodamineis adopted as tracer substance. In this experiment, the tracer concentration is measuredby pictures which are taken by a camera in the side of the vegetation area. The tracerconcentration is reflected by the brightness of the picture. The experiment shows thatthe existence of vegetation can effectively control the downstream water pollution.