A “jewel at risk”: Venice and the historical phenomenon of acqua alta

The frequency of flooding in Venice has drastically increased over the last 50 years as a major consequence of natural and anthropogenic land subsidence, and a more active lagoon hydrodynamics induced partly by deepening of the largest navigation channels. Is Venice dying, a victim of its environment and of its own success? Many people fear so: the local residents who observe the decline of their beloved city, the Italian authorities, the millions of visitors. Beyond the splendour of restored churches and palaces, beyond the magnificent façades the reality is dramatic: the city is now often admired from gigantic ships in the Giudecca canal by cruisers of modern times. The survival of Venice as a living and vibrant city is at risk. The lagoon environment has always been characterized by a pronounced morphodynamics, inducing important morphological changes to the lagoon setting over the relatively short time of a few centuries. The aim of this paper is to analyse the disasters history of this fascinating world surrounded by waters. In fact, the economic system and the existence of the “Serenissima” Republic itself was based on “water”. Water meant refuge, safety, nourishment, wealth, military strength, and prospect for new developments.