River channel confluence routing based on steep slope

The one-dimensional hydrodynamic model is widely used in the study of river flood evolution by studying the time-varying patterns of hydraulic factors such as river cross-section flow and water level. The Saint-Venant equations are based on the assumption that the river bottom specific drop is very small, and the difference between water depth h and Z-Zd can be ignored, that is, cosα≈1.0, where α is the river bottom specific drop. However, this small slope assumption is invalid for mountainous areas or real steep river topography in headwaters. On the basis of considering the specific drop of the river bottom, the study decomposes the runoff gravity and pressure in the direction of water flow movement, constructs a flow calculation equation based on the momentum decomposition of steep slopes, and uses a power law curve to limit the parameters of the equation, thereby more accurately simulating steep slopes. Flood evolution movement in river channels.