LAUSR

Various vegetations are often grown on floodplains, and it has a significant influence on the movement of water flow and the protection of river slopes. In the experiments performed in this study, a cylindrical aluminum column with a diameter of 4 mm was selected to simulate natural vegetation and 7 classes of slopes ( i  = 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%, where i is the percentage of slope) and four categories of lodging angles ( θ  = 20°, 40°, 60°, and 80°) were assigned. The experimental results show that when i  > 0%, the curves of Manning’s roughness coefficient ( n ) and flow depth ( h ) converge, and the degree of convergence gradually increases with the slope. In addition, Manning's roughness coefficient increases with the increase in slope at shallow flow depths, and decreases with the increase in slope at deeper flow depths. Exploration of the relationship between slope and vegetation roughness not only provides a theoretical support for flood control, but also has practical significance for river ecological environment management.