Modeling ship-induced waves in shallow water systems: The Venice experiment

As the size of vessels progressively increases to compete in the global trade, the impact evaluation of navigation in waterways and shallow coastal ecosystems become more important. Therefore, suitable tools to investigate processes are required to support a sustainable management of ship traffic. This work tests a new methodology, based on a numerical model chain, that reproduces the hydrodynamic field close to the ship hull and the ship induced wave propagation in the surrounding shallow areas. The model chain includes an unstructured hydrodynamic model forced by the near-field estimation of a computational fluid dynamics simulation. The modeling system has been applied to a major navigation channel and surrounding tidal flats in the Venice Lagoon (Italy). Field observations and a theoretical framework were used to characterize the ship waves and to validate the modeling system. Results show that the deeper the initial depression, the larger the dissipation over the tidal flat. In these conditions smaller vessels sailing at higher speed produce smaller waves with low amplitudes compared to larger ships traveling at lower speed. We considered vessels moving at different speeds providing useful information to evaluate impacts and to define criteria for decision support systems for a sustainable management of navigation.