ABSTRACT
The height of a normal tide in the Lagoon of Venice reaches elevations ranging from 0.4 m to 0.6 m.
Flood tides occur mainly during fall and winter, in concurrence with low atmospheric pressure, enduring rain, and strong winds blowing from the southeast across the Adriatic Sea. When tides exceed +1.2 m and +1.4 m above mean sea level, respectively, 40% and more than 60% of the city area is flooded.
During the last century, the sea level has risen, and the land level has dropped; as a result, Venice has ‘sunk’ 240 mm with respect to the sea, and floods have become more recurrent and intense.
This phenomenon has been triggered by the eustatic rise of the sea level, by natural subsidence, and, since the 1920s, by additional subsidence due to water extraction. In the early 1970s, water extraction from wells in Venice and Mestre area was prohibited, and man-induced subsidence was halted.
