Venice’s ‘Moses’ Dam: Salvation or Curse?

The topic of conversation this summer in Venice, Italy, is the $3 billion MoSE (Modulo Sperimentale Elettromeccanico), a series of 78 hinged movable steel gates that officials hope will stop the flooding that is destroying the fabled city. The gates are comprised of linked water-filled steel containers that, when pumped with air, will rise to block seawater from entering the Venice Lagoon; eventually they will span across the lagoon’s three inlets like giant rows of teeth. Construction on the project began in May and was commemorated in a ceremony attended by Italy’s prime minister, Silvio Berlusconi. The historic moment had been long in the making: Italians have been debating the merits of MoSE (also Italian for “Moses”) for the past 17 years.

Yet now that the project is under way, more people than ever are criticizing it. Environmentalists, including Italy’s Green Party, say the project-for which 16 million cubic feet of the lagoon bed will be dredged and replaced by 8 million tons of rock and 700,000 tons of concrete-will threaten the ecology of the lagoon, one of the Mediterranean’s most important wetlands. Anodes protecting the gates from corrosion will release more than 10 tons of toxic zinc in the lagoon per year; the toxins could accumulate in the food chain. And when the gates are closed they will trap industrial and agricultural pollution, as well as the city’s untreated sewage, which is usually flushed out by the tides. Jim Titus, sea-level rise expert at the EPA’s Global Change Information Branch, notes, “As the sea level rises, they’ll have to close the gates more and more often-but if they do that, they’ll mess up the estuary. So really Venice is either going to have to elevate the walks and give up those lower stories or make the estuary a freshwater lake.”

Francesca De Pol, spokesperson for the Consorzio Venezia Nuova (New Venice Consortium), which proposed the MoSE project, says the city’s ground level has already been raised as much as it can be without altering its architecture. Layer upon layer of pavements and foundations have been built over the centuries in a constant effort to keep the city above water, and the ground floors of many buildings have already been abandoned. Despite these efforts, De Pol says St. Mark’s Square, one of the city’s lowest points at 31 inches above sea level, floods about 200 times per year; saltwater is also slowly eroding the porous brickwork of the palaces along the Grand Canal. She asserts that the MoSE system is the answer to these and future problems, as the system has been designed to adapt to projected scenarios of sea-level rise for the next 100 years.

Environmentalists disagree. In the last century Adriatic tides have been getting higher and more frequent, and the city has lost nine inches against the sea—a combination of rising sea level and sinking ground. Deep channels dredged through the lagoon’s inlets for the shipping of raw materials have resulted in stronger currents, which in turn have brought faster tides and erosion of the salt marshes. Colgate University archaeologist Albert Ammerman has found evidence that Venice has been sinking much faster than anyone previously thought, and he thinks the MoSE plan seriously underestimates the likely rate of sea-level rise during the coming century. The Italian Ministry of the Environment claims that the gates will have to be deployed 40 or 50 times a year rather than the 5 or 6 projected by the consortium. In fact, environmental experts believe that the extremely costly dam mechanism could well be obsolete within a few decades.

Furthermore, critics claim that the consortium has a lot to gain economically from the project. Set up by the Italian government nearly 20 years ago with a mandate to safeguard Venice, the group is comprised of engineering and construction companies that would not be subject to a competitive bidding process. Once the dams are built, members of the consortium could reap millions of dollars a year for operation and maintenance of the MoSE system.

The MoSE project is expected to provide 10,000 jobs over 10 years. Yet in a city where the population has diminished to less than half of what it was 50 years ago, this added employment is of uncertain benefit. As 13 million tourists deluge Venice yearly, residents are leaving for more affordable places, which is contributing not only to the failure of local amenities like food markets but also to the loss of a Venetian identity and culture. “Now that Venice has become a global city, it has lost its local roots,” says Luca Muscarà, a Venetian who teaches urban geography at the University of Rome. In a nod to the MoSE controversy, he adds, “It seems that Venetians 500 years ago knew much more about the local ecosystem than they do now.”

Categories: Cities