In river bends, sediment transport characteristics, bed topography and bend evolution are directly influenced by bedload movement, such as four typical laws of bedload transport, much more bedload transport from convex reach to convex reach than from concave reach to convex reach, banding transport of bedload, formation of transverse bed slope, and transverse sorting of bedload. This paper sums
... [Show full abstract] up five formulas of bedload transverse transport intensity and analyzes its relationship with transverse bed slope using Parker's formula. The analysis indicates that the concave-to-convex transport intensity is decreased as the bed slope increases. When the slope reaches a certain value, the intensity will become zero. A further increase of the slope beyond this value will cause a direction change into convex-to-concave transport. The equilibrium mechanism of transverse transport on a steep slope of concave reach generally is different from that on a gentle slope of convex reach. This steep slope often depends on grain submerge weight, transverse circulation, bed particle size and bedload sorting, while the gentle slope depends on upstream incoming sediment, transverse circulation, bed particle size and bedload sorting. Static balancing or moment equilibrium of bedload particles is a key factor that determines equilibrium mechanism. Under the transverse sorting mechanism the bed slope has to adjust itself through a dynamic reiterative process, while bedload sorting always develops to favor reduction of transverse bed slope.