The Influence of Riparian Vegetation on the Hydrodynamic Characteristics of Compound Channel

The influence of different vegetations widely habituating on the floodplain of natural rivers on the hydrodynamic characteristics of compound channel has always been concerned. This study has established a numerical model of riparian vegetation flow of compound channel based on Delft 3D software, and adopted the diameter, height and density of vegetation as control parameters, to investigate the influence of these parameters on the longitudinal water surface slope, lateral profile of depth-averaged longitudinal velocity, and the ratio of difference of velocities in main channel and flood plain to the average velocity of whole cross section. Research indicate that the increase in diameter, depth and density of vegetation changes the lateral profile of longitudinal velocity significantly. The ratio of difference velocity and the water surface slope are correlated with the diameter of vegetation quadratic, with the height of vegetation linearly, with the density of vegetation logarithmically. The difference between water surface slopes of main channel and flood plain increase as long as the increase in diameter, height and density of vegetation; and the maximum velocity in the main channel is shifted due to the imbalance distribution of vegetation.