It is the city from which merchant traveller Marco Polo set sail on his journey of discovery to Asia, and it symbolizes the way humankind has tamed the natural elements through architectural accomplishments and technical innovation. Picture a city by the sea so rich in monuments, art, history and beauty the whole world wants to visit at least once in a lifetime. Now imagine that same city slowly subsiding - say by 16 cm in the last century - while the sea level is increasing, with a constant threat of flooding. Well, that city is Venice, the worldwide renowned open-air museum built upon a group of 117 small islands situated in a shallow 550 km² lagoon at the northwestern end of the Adriatic Sea.
This large, enclosed bay is protected by a line of sandbanks, and connected to the sea by three inlets, which enable passage of the city's marine traffic, as well as the normal 1-meter tides that flush the city's canals. But the lagoon is also subject to large variations in water levels, including extreme spring tides that regularly surge through the city and flood homes, businesses and buildings with seawater. As sea levels are forecasted to rise about 20 cm by 2050 as a result of global warming, the city of Venice risks to be inundated nearly once a week with tides starting from 80 cm above normal.
The solution to save Venice from sinking consist in a multi-billion dollar flood barrier system - the MO.S.E (the Italian acronym for the Experimental Electromechanic Module) - with 78 flood barriers embedded in the sea floor at the three inlets to Venice's lagoon. These water-filled hollow steel boxes remain on the sea floor and when needed can be raised with compressed air in 30 minutes, creating a barrier able to withstand incoming high water levels up to three meters above normal.
The brain of this system is an ABB distributed control system based on the Symphony Plus automation platform. It will raise and lower the 78 barriers in accordance with pre-set parameters, whenever high water approaches or leaves the lagoon. Further to that, ABB will also provide an integrated electrical automation solution for the whole project. The complete solution will manage signals from more than 50,000 devices and coordinate operation of the entire flood protection system, consisting of navigation locks, breakwaters and flood barriers to shield the lagoon from rising sea levels, winter storms and spring tides, and protect Venice and neighboring areas from flooding.
Once in operation, the MOSE and ABB will allow Venice, its citizens and millions of tourist a year to enjoy this longstanding member of the Unesco Word Heritage for many years to come. Serenely.