Abstract:
The morphology of estuaries and rivers changes constantly due to the dynamic imbalance between the
forcing actions (e.g. river flow, tides, surface waves and wind) and the sedimentary reactions. Understanding
and predicting these changes are very important for an scientific-based, sustained management
of these systems. Morphodynamic process-based numerical models can be used for this purpose. The
development and validation of a new three-dimensional unstructured grid morphodynamic modelling
system, MORSELFE, aiming at simulating short-term morphological evolutions of estuaries and sandy rivers
(temporal scale of days to month), are presented. MORSELFE couples a three-dimensional hydrodynamic
model, with an advection–diffusion transport model for the suspended sediments, an empirical
formula for the bed load, and a bed updating module. The model considers the simulation of non-cohesive
sediment and does not account for wave effects. A new approach is proposed to compute the erosive
fluxes, which adapts them to the vertical grid resolution. The use of unstructured grids and the implementation
in parallel mode make MORSELFE particularly adapted to engineering applications. The model
was assessed and validated against analytical and experimental test cases, also allowing the inference on
the optimum choice of the model parameters and variables.