With its 550 km2 of surface area is the largest wetland of the Mediterranean. It is divided from the sea by a strip of barrier islands, the littoral, that runs for about 60 km, interrupted by the lagoon inlets of Lido (800 m wide), Malamocco (400 m wide) and Chioggia (380 m wide). Inside the lagoon basin are Venice, Chioggia and more than 50 islands, among which Murano, Burano and Torcello; about 40 km2 of salt marsh (low-lying areas which are covered with halophytic vegetation); a 1,500 km network of canals that ensures the propagation of the tidal currents. The depth of the lagoon is generally between 1 m and 3 m.

The drainage basin is the part of the mainland that channels fluvial waters and rainwater into the lagoon. It has a surface area of about 2,000 km2 that is crossed by a hydraulic network that pours about 2.5 million m3 of water a day and about 30,000 m3 of sediments per year into the lagoon in 27 different places. Just over 70% of the area is used for agriculture. The drainage basin is divided among some 100 or so local authority areas in the provinces of Venice, Padua, Treviso and Vicenza, with a total of nearly 1 million inhabitants.

It governs the lagoon ecosystem with its tides that enter and exit of the lagoon twice a day through the inlets, reaching two maximums and two minimums. It has been calculated that the volume of water exchanged daily between the sea and the lagoon is about 400 million m3. The average range of tide heights in the lagoon is about 1 m. Nevertheless, the tidal level is subject to important variations, above all in relation to astronomical and meteorological factors. When the tide grows to the point of provoking floods in the historic centres of the lagoon, the so-called phenomenon of "acqua alta" occurs.

The objective of the measures is to safeguard habitats such as salt marshes, mudflats and shallows, which guarantee essential ecological and hydrodynamic functions and ecosystem biodiversity. The activities involve a series of restoration and protection measures ranging from actual reconstruction to morphological restoration and experiments involving techniques able to accelerate the formation of diversified habitats. Many species of waterfowl found in artificial salt marshes a perfect setting to rest, feed and, in many cases, nest. Today the lagoon of Venice is one of the most important sites at national level for the conservation of characteristic wetland waterfowl.

The main activities involved isolating the polluted land to block the dispersion of contaminants from the canal shores in Porto Marghera and from dumps used in the past to dispose of industrial waste. Other activities involve the creation of “phytobiopurification” areas – special wetlands between the mainland and lagoon able to filter the water coming from the mainland and reduce the content of pollutant.