A dynamical model for the coupled¬ evolution of channels and tidal flats

A dynamical model for the morphological evolution of channels and tidal flats is proposed. Both channels and tidal flats are schematized as sediment reservoirs, whose depths are the only two dynamical variables of the system. The two reservoirs exchange sediments through the tidal dispersion mechanism. The reference concentrations are determined by currents and waves, which are function of the geometry of the system. The hydrodynamic component of our simplified model is compared to the numerical model Delft3D, showing good agreement. The morphological model shows that, without wind waves, a flat bottom is unstable and the only stable configuration is a channel without tidal flats. For intermediate wave conditions, a non-trivial stable equilibrium arises, characterized by a channel flanked by tidal flats. Intense waves suppress the channelization process, and a flat bed becomes then only stable equilibrium. Finally, relative sea level rise allows the coexistence of channels and tidal flats, even in absence of waves.

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