EGU2020-20909, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-20909
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The effect of flow variability on the river meandering dynamics

Francesca Bassani, Matteo Bernard Bertagni, Luca Ridolfi, and Carlo Camporeale
Francesca Bassani et al.
  • Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, 10129 Turin, Italy (francesca.bassani@polito.it)

The dynamics of a meandering river has been widely investigated by the scientific community. However, the effects of discharge variability on the meander evolution is still an open question. In this work, we present numerical simulations of the short-term evolution of a plane river morphology (the Ikeda, Parker and Sawai model is used to describe the stream hydrodynamics) forced by a stochastic flow discharge (simulated by a compound Poisson process). The comparison of the simulation outcomes with those obtained for the same river under a constant discharge (equal to the mean of the stochastic process) shows interesting results. The discharge variability slows down both the formation of the meanders and the occurrence of the cutoff events, and induces lower meander curvilinear wavelengths and excess bank velocities. A theoretical analysis of the relationship between the channel erosion rate and the river discharge for the Kinoshita curve confirms the obtained numerical results.

How to cite: Bassani, F., Bertagni, M. B., Ridolfi, L., and Camporeale, C.: The effect of flow variability on the river meandering dynamics, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20909, https://doi.org/10.5194/egusphere-egu2020-20909, 2020

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  • CC1: Hydrodynamics and meander belt, Andy Mitten, 04 May 2020

    Thank you for the interesting presentation.

    In the initial parameters for the models, what is the initial channel depth? How often do your stochastically generated discharge rate exceed this? If they do, how are your results effected by the chute cut-off this might produce?

    Many thanks

    Andy

    • AC1: Reply to CC1, Francesca Bassani, 04 May 2020

      Thank you Andy for your comment.
      We set the initial channel depth to 1.8 m which is the mean of the stochastic process, so it has the 50% probability of being exceeded.
      As regards the chute cutoffs, our code considers the neck cutoffs only. Since they affect the long-term dynamics (filtering action on the planimetric evolution), we focused on the short-term river behavior.

       

      Francesca