An Improved Method and the Theoretical Equations for River Regulation Lines

The regulation of wandering rivers is a universal problem that attracts significant attention. To effectively control the dynamic state of river course, it is necessary to adjust and construct river training works, which can be regarded as inseparable parts of the planning of river regulation lines. In this study, by comprehensively analyzing the water and sediment discharge in the wandering river of the Yellow River over the period 1952–2020, the large change in water and sediment conditions will inevitably affect the change in river regimes. By analyzing the river regime evolution process from 1990 to 2020 and calculating the river change index, it is found that the wandering channel of the Yellow River has gradually been stabilized, and there is no longer a large channel change, but a small amplitude swing still occurs frequently since 2010. Therefore, these phenomena highlight an urgent need for improving the planning of river regulation lines. According to the properties of parabola, circular arcs, elliptical arcs and curvature arcs, these curves are used to describe the flow path of the river. The theoretical equations of river regulation line with four curve forms are developed based on the latest river regimes and the location of the existing training works as the basis. Four groups of theoretical equations were verified by selecting typical river bends or reaches. The innovative practices from this study may assist in providing technical references, which control the frequent changes that occurred in river regime, as well as guaranteeing the healthy and sustainable development of rivers.