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Keywords:

  • bank erosion;
  • bend irregularity;
  • compound loops;
  • floodplain heterogeneity;
  • meandering rivers;
  • stochasticity

[1] Although it is widely acknowledged that spatial heterogeneity in floodplain erosional resistance should affect the planform evolution of meandering rivers, past studies have not systematically explored the importance of this effect. Using a physically-based model of river meandering and stochastically-generated heterogeneous landscapes, we analyze in detail how spatial variability in erosional resistance influences meander evolution and the emergence of planform complexity. The simulated planforms are remarkably similar to natural freely-meandering rivers, both visually and in their spectral signatures. We quantify the dependence of meander morphology on both the scale of erosional heterogeneity and the magnitude of erosional variability in external forcing. We also show how the sensitivity of autogenic meandering processes to stochastic variability in the environment leads to different patterns of planform evolution even in landscapes with the same mean spatial heterogeneity and magnitude of variability. The results demonstrate that heterogeneity in erosional resistance has a major influence on meander evolution and should be incorporated into morphodynamic models to enhance our understanding of meandering dynamics at the landscape scale.