Number of historical high tide events in Venice in Italy 2018, by month

From October to March, Venice experiences repeated flood events. Over this period, seasonal and local winds, combined with other meteorological phenomena, can interfere with the tidal reflux in the Venetian Lagoon. While most flood events have limited impact, in some cases they can bring exceptionally high water levels. Among all recorded events where the water level exceeded 110 cm (3.6 feet), 94 occurred in November. In November 2019, Venice experienced the second highest tide since 1872, when flood records started, reaching a peak of 187 cm (6.1 feet) above sea level.

Flood events in recent history

Between 1966 and 2018, Venice was flooded on average 67 times a year. Some 3,553 high tide events were recorded over this period. The majority caused only minor inconveniences: over the period under consideration, the water level remained under 90 cm (three feet) above sea level in 60 percent of the cases. The water level exceeded 170 cm (5.6 feet) only once: during the 1966 tide, it reached a peak of 194 cm (6.4 feet).

The MOSE project

The flood barrier MOSE (Modulo Sperimentale Elettromeccanico) was designed to protect the city of Venice and the Lagoon from the tides of the Adriatic Sea. Originally expected to be operational by 2014, it has been under construction since 2003 and won’t be ready before 2022. The project keeps attracting controversy because of its scale, the large delays and cost overruns, and even a corruption scandal uncovered in 2013. In 2018, one in two Italians agreed with the construction of the flood gates, while one in four did not. According to its critics, the project was not designed to shield the Lagoon from the kind of floods expected to occur in the future. The flood risk in Venice, in fact, is going to be exacerbated by a combination of climate change and land subsidence. There is also an issue of costs: in the event of more frequent floods, repeated contact with saltwater will drastically reduce the gates' lifetime as well as increase their maintenance costs. However, since the project is close to completion, the consensus is that it would be reasonable to finish it. Designed to protect the Venice Lagoon from tides of up to three meters (9.9 feet), it could have prevented the 2019 flood which led the Italian government to declare a state of emergency for Venice.