The Venetian Bind: The Tides of Floodwaters and Tourism Both Threaten

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Venice is a city in dire peril. Or so we're told in every article written about this spectacular place. I'll get to the validity of that idea later, but first let's look at Progetto MOSE [1], the gigantic public works project touted as the city's savior.

The city is an international treasure. But even for someone not concerned about Venice, the project now being built to alleviate flooding represents -- for better or worse -- the kind of intersection of science, engineering, politics, and business that will become more common if the melting icecaps bring about the predicted rise in sea levels.

MOSE (Modulo Sperimentale Elettromeccanico, or "Experimental Electromechanical Module") is an ambitious civil engineering endeavor intended to prevent exceptional high tides (above 110 centimeters, or about 3.5 feet above sea level) from entering the Venetian Lagoon. On completion, a submerged mobile barrier of huge metal boxes full of water will be hinged to a reinforced concrete foundation on the floor of the three inlets through which the Adriatic Sea gives and receives water every six hours.

When an exceptional high tide is imminent, these caissons will be pumped full of air, causing them to rise and block the inlets. When the tide subsides, as it always has, the caissons will be flooded again, returning to their underwater resting position. Venetians still must keep their Wellington boots at the ready, however, because this unusual behemoth will not be used to block normal high tide. The projected cost: $5 billion. Anticipated completion: 2012.

Ever since the first design was presented, the project has aroused powerful reactions, pro and con. Italia Nostra, a prominent group dedicated to Italy's heritage and environment, has been adamant in its protests against the plan. In a long report issued before final approval of the project, predictions of environmental damage were stark: "The dams will render permanent the lagoon's environmental imbalance: The deep channels dredged in the last century through its outlets will become concrete. The erosion that is eating away the lagoon's precious wetlands would become permanent, and this rich coastal lagoon, protected by European law, would be transformed into an area of open sea."

MOSE is one-third completed, but people continue to protest. Why? Doesn't it seem obvious that saving Venice is something everybody ought to be in favor of?

As a resident of Venice, let me evaluate the situation as objectively as I can. First, some essential background: On November 4, 1966, an exceptional high tide in the Venetian Lagoon rose almost 6 feet above sea level, or about chest height of anyone sloshing across the famous Piazza San Marco, the city's lowest point. A strong southeast wind prevented the normal turning of the tide until eight hours later. What the flood left behind wasn't just ruined refrigerators and sodden sofas but also an intense international desire never to see Venice endure such an inundation again.

Since then, virtually all accounts of high water, even if only 3 inches, are written in phrases that connote disaster and doom: The waters don't just rise; they "invade" the city. Such apocalyptic descriptions are so far from the reality of normal high water (much more common, though fairly random), as the citizens of Venice experience it, that they regard them as something close to fiction. I have read a purportedly reliable official source that states Venice experiences high water 250 days a year. As someone who has lived in the city fourteen years, I can confirm that this figure is wildly inaccurate. During the past nine months, I think I've put on my rubber boots just once.

Even though various experts have said a tide as high as that occurred in 1966 isn't likely to happen again for a few centuries or more, in the years since the Big One, a newer fear -- that melting polar ice will raise sea levels -- has revived the discussion of how urgently we need to prevent the Venetian Lagoon from threatening the extraordinary city it surrounds.

Some people claim MOSE will derange the tidal patterns in the lagoon, creating chronic problems for one of the largest and most important wetlands in Europe. Others say pollution created by the zinc plates and the antifouling paint on the boxes will harm both the lagoon and the Adriatic. Some object to the phenomenal cost; yet others scoff because they claim that after twenty years of legal battles, the design was obsolete before work began. Still others point out that such a massive public work has skirted European regulations in a number of ways, including a failure to submit a complete environmental-impact statement.

But back to science: All the claims and counterclaims about MOSE, apart from the legal ones, are based on best guesses. Science can tell us very little today, with any reasonable certainty, about either the efficiency of this multibillion-dollar project (which so far has been tested only once) or the future extent of sea-level increase.

At this point, all anyone can say with absolute certainty is that we have no idea how well MOSE will work, how often it is likely to be used, and whether its use will create unpleasant problems. We will probably need several decades before an intelligent evaluation can be made. It's not reassuring, however, that the current mayor of Venice, Massimo Cacciari, has predicted "irreversible alteration of entire habitats that are protected by the local, national, and European regulations from their degradation and pollution."

Pierpaolo Campostrini, the director of CORILA, a consortium for the management of research on the lagoon system, who favors MOSE, acknowledges possible environmental problems but cautions that "we mustn't forget that the barriers will be raised only in the case of tides above 110 centimeters. According to the predictions, this would only happen on the average between four and seven times a year, without creating any noticeable alterations in the lagoon ecosystems."

Let's be optimistic and imagine that MOSE works really well and creates no problems for the vast biodiversity of the lagoon. Has Venice been saved from anything except some water in the streets for a few hours a day?

How much danger is Venice really in? Many visitors know a lot about the city's history, architecture, and works of art. But most know little or nothing about the day-to-day realities of the city they're intent on saving.

For example, most don't know that the thousands of motorboats traveling the canals each day create waves far more destructive to the city's foundations than the sporadic high water. They don't know that while money is poured into MOSE, every day something else is cut from the municipal budget.

The most overwhelming inundation in Venice is the tide of tourism, which rises dramatically as the resident population shrinks. In 2006, there were fifteen million visitors, a virtual tsunami in a town that covers just 3 square miles. Whether this information inspires emotion or not, it is more measurable than the inexact, politically driven "science" that gives us predictions about MOSE and the acqua alta.

So let's say that all these unglamorous but very real problems remain unresolved: Young families move away because they can't afford Venice, older generations die off, and hordes of tourists -- tended to by merchants on the mainland -- finally render the city completely unlivable. Let's also say that predictions of high water turn out to be true, and that MOSE functions perfectly.

In fifty years, the Venice that has been "saved" will amount to nothing more than a bunch of really old buildings -- beautiful or not, according to your opinion.

If no comparable effort is undertaken to revive and protect the life of the city, even if MOSE turns out to have been an engineering marvel, the once-thriving city will be as devoid of daily life as Machu Picchu. There's not much point blaming MOSE for that, or bewailing the triumph of politics and fear over science. But it seems clear that if the time, energy, and billions of dollars that will have been spent to hold back the tide had been dedicated to resolving the chronic problems Venice experiences every day, in fifty years there would still be a living city worth saving.

Erla Zwingle, a contributing writer for Edutopia, lives in Venice.