3-D numerical simulation of morphological responses to cutoffs in meandering channels

Navigation in meandering channels usually requires straightening the river. Cutoffs across the neck of long meander bends improve the alignment of the river, reduce sinuosity, and shorten the river length, thus increasing the channel slope. In the present paper, the planform evolution of a meandering channel with cutoff is simulated by a 3D mathematical model, in which turbulence flow, sediment transport and bank erosion were modeling. The simulated results demonstrated that the upstream processes of meander evolution with cutoff had been accelerated compared with the meander evolution without cutoff, and the accelerated magnitude of evolution was decreased from downstream to upstream. The meander evolutions downstream of cutoff are similar to that without cutoff, with channel widened, except for the transition segment between pilot channel of cutoff and the downstream meander.