Venice: Acqua Alta
Water is an integral part of Venice’s identity and a key element of its urban landscape. Over the centuries, the city has adapted its lifestyle to cope with high tide, or Acqua Alta, and has accepted the negative economic consequences. Rising sea levels not only flood large parts of the city, but also make it impossible for boats to pass underneath bridges, hindering the delivery of goods and movement of people. Moreover, the exponential growth in the frequency of high tides since the 1900s is putting an increasing stress on the stone foundations of buildings. Maintenance is costly and the saltwater intrusion in the brick above the marble foundations is putting Venice’s architectural treasures at risk. The city’s vulnerability is also exacerbated by the compression of sediments beneath the city and the subsistence brought by groundwater extraction that resulted in ground level lowering more than 10 cm in many areas, especially in the easternmost district. Since 1897, seawater levels increased, making Acqua Alta more frequent and the phenomenon is expected to hit the city
Over the last century, sea levels increased 20 cm and the figure is expected to reach 85 cm by the end of the century. Image (top): Acqua Alta is a phenomenon that occurs mainly between autumn and spring, when the astronomical tides are reinforced by the prevailing seasonal winds which hamper the usual reflux. The main winds involved are the sirocco, which blows northbound along the Adriatic Sea, and the bora, which has a specific local effect due to the shape and location of the Venetian lagoon. Acqua Alta does not last long and often floods San Marco's square. Venice, Italy. Source: Jean-Pierre Dalbéra/Flickr (bottom): Acqua Alta. Venice, Italy. Source: Gwenael Piaser / Flickr (right): Boston Harbor, USA. Source: Freaktography / Flickr
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more often and with more strength in years to come due to climate change. The city is in the process of realizing a system of underwater barriers to be raised in case of extreme flooding. The MOSE Project is expected to adapt the Venetian Lagoon from flooding and mitigate the damage that could be done from rising water levels. The Modulo Sperimentale Elettromeccanico (Experimental Electromechanical Module) comprises 78 mobile gates which will separate the lagoon from the sea. The proposal dates back to the 1970s, when the Venice Water Authority was entrusted to design and implement the measure to safeguard the city. However, many Venetians are still skeptical of it due to the high costs and the potential environ-
mental risk that its completion may bring. The main problem with the MOSE Project is the amount of money needed to create public infrastructure. The price is estimated at €7 billion and will no doubt increase before the completion of the project in 2016. The concentration of this capital in a public construction project also attracted political corruption. Prosecutors have tracked the transfer of funds to political parties on local, regional and national levels from the contractors of the project. As a result, in June 2014, 35 people, including the Mayor of Venice, have been arrested and assets worth €40 million have been seized during the corruption investigation.