The lagoon maintains a connection to the northern Adriatic Sea through the inlets of Lido, Malamocco, and Chioggia, and the exchange of water through the inlets in each tidal cycle is about a third of the total volume of the lagoon. The northern Adriatic Sea is a shallow and semi-enclosed regional sea, influenced by the plumes of large rivers (Po, Adige, Piave, Tagliamento). The Venice Lagoon constitutes a complex system of major historical and environmental interests that is under the pressure of anthropogenic factors and global scale processes bringing about noticeably rapid changes to the environment. It is characterized by a complex pattern of major (navigable) and minor channels, salt marshes, tidal flats and islands, which have been artificially modified by man throughout the centuries. In response to the increasing frequency of floods determined by natural and anthropogenic subsidence and sea level rise, the last significant intervention is the construction of a system of mobile barriers at the tidal inlets, known with the acronym of MoSE. The project entails building mobile barriers at the bottom of each inlet that will rise and separate the lagoon from the sea when the expected tidal elevation becomes critical. In a future scenario of rising sea level, the MoSE will then transform the lagoon in a regulated system, due to the intensification of management actions, which will result in changes in hydrodynamics and in the transport of sediments, contaminants and organisms.
Like all shallow water transitional areas, the Venice lagoon is a constantly evolving environment, where the exchanges at the tidal inlets drive biogeochemical and morphological processes in dynamic key areas such as mudflats, wetlands, and the dense network of channels influencing coastal erosion and accretion patterns. The knowledge of the processes at the lagoon-sea interface represents a focal point for the safeguard of Venice, the lagoon and the functionality of the ecosystem. In situ monitoring in the lagoon, the inlets and the coastal waters is carried out by several agencies and a regional observing system to support environmental monitoring and reporting is being currently setup.
In the framework of national and international projects, CNR-ISMAR has been involved in the integration of large dataset of experimental observations (hydrodynamics, sediment transport, optical water characterization) with analytical and numerical models able to provide a synthetic vision and to predict the evolutionary trends in the medium and long term. ISMAR is also supporting the management, the monitoring and the definition of strategies for the safeguard of the lagoon during the operational phase of the mobile gates.
Thirteen fieldwork activities were carried out in Venice Lagoon and adjacent coastal waters for the period February- September 2020. About 90 sampling stations were visited synchronously to Sentinel-2 and Landsat 8 overpasses, collecting above-water reflectance, CTD and turbidity profiles, Secchi disk depth, water sampling for total suspended matter and chlorophyll-a concentrations.