Testing the characteristic timescale of the morphodynamic feedback in meandering channel migration
The sinuous shape of meandering river channels drives variations in flow velocity and causes the channel to migrate laterally, which in turn changes the channel shape. This planform-migration feedback is embedded in all conceptual models of meandering channel migration, where the timescale of this feedback is represented by the model time step. However, the sensitivity of the modeled channel trajectory to this time step is unknown. Using a series of numerical experiments, we show that channel migration trajectories are consistent if the channel migrates less than 10% of its width in one model step. This geometric constraint suggests an upper bound for the timescale of the morphodynamic processes that are most determinative for channel migration. It also sets a maximum time step for finite-difference models of meandering channel migration, which can be directly used in landscape evolution models that couple meandering channel migration with varying spatial scales and migration rates, over timescales from years to millennia.
Related paper:
- Li, Y., and Limaye, A. B., 2024, Timescale of the morphodynamic feedback between planform geometry and lateral migration of meandering rivers, Journal of Geophysical Research: Earth Surface 129 (2), https://doi.org/10.1029/2023JF007413