The Venice Flood Barrier consists of 20 m wide steel gates that are resting on the sea floor in large concrete caissons. The caissons were lowered into a trench located across the tidal inlet. When the barrier should be closed, air is pumped into the gates.
The gates float up and close the
tidal inlets. In total over 1500 m of gates were placed in the three inlets to the Venice Lagoon. In the Chioggia inlet in total eight caissons of 60 m width were placed for the foundation of the storm surge barrier.