On the Prediction of the Characteristic Times of River Meander Cutoff Sequence: Theoretical Model and Comparison With Laboratory and Field Observations

River meander dynamics inevitably interferes with a number of human activities and productive processes. Therefore, investigating the involved physical processes and modeling their space‐time evolution represent a crucial requirement in terms of sustainable river management and restoration planning. In the present study, a deterministic integral‐differential equation that governs river‐bend growth and death in the absence of natural or anthropic forcing is for the first time derived and solved by resorting to cardinal fluid‐mechanical equations such as Navier‐Stokes’ in the Lamb‐Oseen version. The related 1‐D model, which accounts for morphology and sedimentology via the meander migration rate and its radius of curvature, proves to be able to grasp the periodic nature of the phenomenon. Additionally, it exhibits an overall very good agreement with field pre‐cutoff and post‐cutoff observations, as well as with the outcome of an ad hoc‐designed laboratory experiment that simulated near‐cutoff conditions. Hence, it may represent a fast and easy tool to monitor river bend hydro‐geomorphological evolution, particularly when the signs of the incipient instability suggest quantifying the time left to its routine exploitation and to timely plan, where needed, suitable management and restoration interventions. Key Points An analytical solution in terms of dimensionless fluid‐mechanical circulation versus dimensionless time is for the first time provided in the literature for the modeling of river meander cyclic growth and death and the prediction of the related characteristic times and parameters. The proposed theoretical model hinges on the potential flow approach as the limiting case of Navier‐Stokes‐governed fluxes at very low Reynolds numbers around fast rotating cylinders. Its main distinctive value consists in the simple closed‐form solution and in the capability to account for the periodic nature of river bend cutoff An ad hoc‐designed laboratory experiment was performed in the Laboratory of Hydraulics and Hydraulic Constructions at University of Basilicata to validate the theoretical model in terms of neck width reduction as a function of time in near‐cutoff conditions (i.e., when the correct timing of the process can become a matter of safety even more than management) The results of the validating laboratory tests, jointly with the comparison between theoretical predictions and 20‐year observations at a cutoff site on river Bollin (UK) as reported by Hook