Mathematical modeling of tidal hydrodynamics in shallow lagoons: A review of open issues and applications to the Venice lagoon

Although considerable progress has been made in the application of two- and three-dimensional shallow water models to simulate flow in estuaries and coastal lagoons, a number of outstanding problems still remain in this branch of computational fluid dynamics.These problems mainly deal with the proper representation of physical processes and arise when dealing with very shallow flow, temporary submergence and time-dependent flow domains, and complex morphology, and are often related to inaccuracies in modeling the geometry of the domain. Among others, wetting and drying of salt marshes and tidal flats, inclusion of the small scale drainage networks which often strongly affect hydrodynamics, turbulence closure schemes, and accurate friction evaluation are discussed in this paper.To better illustrate these problems and their possible solutions some examples are presented which use the Venice lagoon as a benchmark shallow tidal basin characterized by a complex interplay of channels and marshes.