Slope And Vegetation Effects On Dynamic Characteristics Of Overland Flow In Modern Watersheds

The dynamics characteristics of the slope surface are the core issues in the study of overland flow hydraulic erosion and sediment transport,and have a significant impact on the accurate simulation of slope abortion and confluence processes.The bottom slope and vegetation are important factors affecting the dynamics characteristics.The change of the bottom slope changes the flow velocity and infiltration pattern of the overland flow.Planting vegetation is an important ecological project in soil and water conservation measures.The interaction between vegetation and water flow increases the resistance of water flow and consumes the energy of water flow,which slows the migration of sediment and reduces the intensity of hydraulic erosion,it has become an important measure to prevent soil erosion on slopes.Spatial distribution of vegetation plays an important role in the surface runoff and runoff distribution and the confluence of flow distribution,thus affecting the distribution of flow patterns among distributed hydrological model grid units.In order to study the vegetation distribution,slope in the water environment protection,ecological river construction,and confirmed that the effect of spatial variability of surface vegetation on surface runoff has directional resistance.The experiment of simulating vegetation water flow was carried out by using variable slope test flume and cylinder,indoor fixed bed flushing test,cylinder simulation of vegetation stalks,vegetation(30°,45°,90°)between the direction of flow and the direction of water flow were simulated to simulate the Froude number,Reynolds number of three kinds of vegetation distributed in five kinds of slopes(0.0%,0.5%,1.0%,2.0%3.0%)Darcy-Weisbach drag coefficient and drag coefficient of vegetation with water depth characteristics.The results show that the energy loss of Froude number,Reynolds number and the distance increases with the increase of slope when the vegetation heading angle and water depth are the same.The slope has no significant effect on the Darcy-Weisbach drag coefficient and the drag coefficient of vegetation.Under the same gradient and water depth,the Froude number and Reynolds number increase with the increase of the vegetation heading angle.The energy loss along the slope decreases with the increase of the vegetation heading angle.The drag coefficient of vegetation,Darcy-Weisbach drag coefficient.The trend angle increases and decreases;under the same slope and vegetation trend,with the increase of water depth,the Froude number first decreases and then tends to be stable,and the Reynolds number gradually increases;the law of the energy loss along the water depth varies with the slope The resistance coefficient of Darcy-Weisbach increases gradually,and the drag coefficient of the vegetation first decreases and then tends to be stable,and there is a boundary water depth beyond the boundary water depth,the water depth no longer affects the change of drag coefficient;large and small,slope changes by changing the water depth of the boundary layer drag coefficient of drag coefficient.