Italia : Venezia : Città d’Acqua

Venice is a city in northeastern Italy and the capital of the Veneto region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 bridges. The islands are in the shallow Venetian Lagoon, an enclosed bay lying between the mouths of the Po and the Piave rivers. Those fleeing barbarian invasions who found refuge on the sandy islands of Torcello, Iesolo, and Malamocco, in this coastal lagoon, learned to build by driving closely spaced piles consisting of the trunks of alder trees, a wood noted for its water resistance, into the mud and sand, until they reached a much harder layer of compressed clay. Building foundations rested on plates of Istrian limestone placed on top of the piles. In 2020, around 258,685 people resided in greater Venice or the Comune di Venezia, of whom around 55,000 live in the historical island city of Venice and the rest on the mainland. The name is derived from the ancient Veneti people who inhabited the region by the 10th century BC. The city was historically the capital of the Republic of Venice from 697 to 1797. It was a major financial and maritime power during the Middle Ages and Renaissance, and a staging area for the Crusades and the Battle of Lepanto, as well as an important centre of commerce—especially silk, grain, and spice, and of art from the 13th century to the end of the 17th. The city-state of Venice is considered to have been the first real international financial centre, emerging in the 9th century and reaching its greatest prominence in the 14th century. This made Venice a wealthy city throughout most of its history. Venice has been known as “La Dominante“, “La Serenissima“, “Queen of the Adriatic“, “City of Water“, “City of Masks“, “City of Bridges“, “The Floating City“, and “City of Canals“. Parts of Venice are renowned for the beauty of their settings, their architecture, and artwork. Venice is known for several important artistic movements — especially during the Renaissance period — and has played an important role in the history of instrumental and operatic music, and is the birthplace of Baroque composers Tomaso Albinoni and Antonio Vivaldi. Although the city is facing some challenges, Venice remains a very popular tourist destination, a major cultural centre, and has been ranked many times the most beautiful city in the world. Venice sits atop alluvial silt washed into the sea by the rivers flowing eastward from the alps across the Veneto plain, with the silt being stretched into long banks, or lidi, by the action of the current flowing around the head of the Adriatic Sea from east to west. Subsidence, the gradual lowering of the surface of Venice, has contributed — along with other factors — to the seasonal Acqua alta (“high water“) when much of the city’s surface is occasionally covered at high tide. Between autumn and early spring, the city is often threatened by flood tides pushing in from the Adriatic. Six hundred years ago, Venetians protected themselves from land-based attacks by diverting all the major rivers flowing into the lagoon and thus preventing sediment from filling the area around the city. This created an ever-deeper lagoon environment. Additionally, the lowest part of Venice, St. Mark’s Basilica, is only 64 centimetres above sea level, and one of the most flood-prone parts of the city. During the 20th century, when many artesian wells were sunk into the periphery of the lagoon to draw water for local industry, Venice began to subside. It was realized that extraction of water from the aquifer was the cause. The sinking has slowed markedly since artesian wells were banned in the 1960s. However, the city is still threatened by more frequent low-level floods — the Acqua alta, that rise to a height of several centimetres over its quays — regularly following certain tides. In many old houses, staircases once used to unload goods are now flooded, rendering the former ground floor uninhabitable. Studies indicate that the city continues sinking at a relatively slow rate of 1–2 mm per annum; therefore, the state of alert has not been revoked. In May 2003, the MOSE Project (Modulo Sperimentale Elettromeccanico) inaugurated, an experimental model for evaluating the performance of hollow floatable gates, expected to be completed in late 2023; the idea is to fix a series of 78 hollow pontoons to the sea bed across the three entrances to the lagoon. When tides are predicted to rise above 110 cm, the pontoons will be filled with air, causing them to float and block the incoming water from the Adriatic Sea. The project is not guaranteed to be successful and the cost has been very high. []