Water is the lifeblood of Venice. Most cities think only of water supply or waterfront property; Venice thinks of water as roadway, marketplace, port: in short, its glue, holding the city together.
What most people don't know, however, is that water is also Venice's greatest threat, and we're not talking about obvious disasters like hurricanes or tsunamis. Venice's greatest threat, one which is beginning to make it a truly endangered city, is more subtle, more gradual. Rising ocean levels present this most unique and beautiful of cities with its most dangerous challenge: a slow and inevitable death, one which can only be prevented if something is done to stop further ice cap deterioration resulting from global warming.
In order to understand just how this problem has developed in addition to how it can be solved, we need to look at some facts. Over sixteen hundred years ago, the seal level of the Adriatic was more than six feet lower than it is today. This may not sound like much, but remember that Venice is a canal city. Imagine standing on the shoreline of a beach, and then add six feet of water. Unless you're quite tall, you would be completely underwater! Venice faces a similar issue. As a city that sits literally at sea level, even a moderate amount of sea level rise can prove disastrous.
Another major issue for Venice is that of rising tides. Water at high tide covered St. Mark's Square only 7 times per year in 1900. Today this event occurs more than 50 times per year, a strong indication that tide levels are becoming more than an occasional nuisance, but rather a consistent menace to the city's ancient architecture. Most building in Venice sit on marble foundations, which harmlessly brush away the rising tides. But rising sea levels mean that the tides now sometimes reach as high as the brick facades above the marble foundation, a material which is much more susceptible to erosion. In a city with so much history and so many artifacts, the results could be disastrous.
Local officials are attempting to combat the rising tides with an ambitious and technologically advanced plan that hopes to literally "hold back the tide." Project MOSE, as the plan is titled, would cost between $2 to $3 billion and require enormous time and effort. The plan calls for the construction of 79 hollow steel gates on the bottom of Venice's harbor. The gates would be submerged and filled with water during normal tides, out of sight and out of mind. When tide levels become dangerous, however, the gates would be filled with compressed air, pushing out the water and allowing the gates to rise up, making them into an imposing physical barrier against the unruly ocean.
The plan has been called at alternate times both genius and madness, and the opinion of both the government and the public has seemed to waver as to whether to go through with it. Politics play a major role: in Italy's ever-changing political environment, it is difficult to determine if votes and pronouncements in either direction will hold weight in the months and years to come, especially when so much of the money needed for Venice's "salvation" could also be well spent on national-level infrastructure improvements. What is certain, however, is that something must be done about Venice's rising sea level problem, before the city itself is slowly transformed into the next Atlantis.
Primary Source: pbs.org