Cutoff processes and their importance for bed and planform morphodynamic adaptation

The majority of current meandering river models treat the cutoff process as a geometric scheme: when the threshold distance between external banks of two bends are getting close enough, the model leaves behind over-matured bends and joins the two channels, then the oxbow lake is produced instantaneously. This does not describe the realistic scenarios. Combining the hydrodynamic model (TELEMAC-2D), morphodynamic model (SISYPHE), and channel migration submodel (MEANDRE), we constructed an integrated numerical model to simulate meander neck cutoffs and their accompanying natural evolutions in bedload dominated rivers. This model is capable to simulate not only in the plane geometry change aspect, but also the real day-to-day channel migration and cutoff events. This model successfully reproduced the laboratory experiment of self-formed cutoff performed by Han and Endreny. It is also effective for a series of test cases including Kinoshita-curve idealized channel cases. Future applications are extended to real world scale simulations.