The MOSE project may not be enough to keep the city dry.
Photo: Awakening/Corbis via Getty Images
On November 3, 1966, a storm propelled by a warm Saharan wind shot up the Adriatic, pummeling northern and central Italy with rain. Venice flooded, as it had, regularly, forever. By the next morning, though, it was clear that this was no ordinary dunking, but a biblical-scale event. The storm kept churning toward the coast, so that even when the tide started to recede, the floodwaters had nowhere to go. Waves demolished 18th-century seawalls, cut off islands, drowned cattle, and obliterated vineyards. Soon, a mass of sludge, more than six-feet deep and glistening with oil that had leaked from blown-out boilers, swirled through virtually every building, and refused to ebb for nearly 24 hours. When the sea finally withdrew, in violent, sucking currents, it left canals choked with mattresses and floating rats and a city traumatized by the worst flood it had ever known.
The first menacing waves of 2020’s fall flood season arrived on October 3, high enough to wash over Piazza San Marco in the tidal ritual known as acqua alta. This time, though, a chorus line of sunflower-yellow parapets rose, one by one, out of the sea in the three narrow passages between the sea and the lagoon. They formed a semipermeable steel wall, and for the first time in Venice’s history, the water was held back. “Today everything was dry,” Venice mayor Luigi Brugnaro said. “We stopped the sea.” Two months later, on December 8, another surge arrived, but forecasters at first deemed it too weak to trigger the 48-hour checklist of analysis, requests, sign-offs, and button-pushing that would raise the barriers again. Venice flooded. Venetians raged. “We’re working on it,” Brugnaro said.
Venetians have gotten used to hearing that. Momentous as its first successful deployment was (and there have been others since), the floodgate system known by the acronym MOSE has been stuck in the “getting there” phase for a lifetime. Authorities announced it in 1976, ten years after the November calamity. In 1986, the government promised that it would be done by 1995. It wasn’t active in time to mitigate last year’s brutal storm, the worst since 1966, and it’s still not quite complete — that’s still a year away (maybe). Meanwhile, the ever-bloating bill is coming in at over $6 billion, much of it sluiced away into the accounts of corrupt politicians, including a former mayor, who was arrested in 2014 on bribery charges. “It was a good idea,” says Luigi Cavaleri, a researcher at Venice’s Institute of Marine Sciences. “Unfortunately, it wound up getting done all’italiana.”
Some of the budget problems and delays flowed from the aesthetic mandate to keep the whole system invisible when it’s not in use. That meant burying the machinery under the sea bed, which Cavaleri says is “very beautiful but very expensive,” not just to construct but to keep in good working order. That’s great news for some well-connected companies. “Those who want to keep milking this cash cow have already lined up to secure the lucrative maintenance contracts,” writes the fierce art historian Salvatore Settis in his 2016 book If Venice Dies. “The MOSE affair demonstrates that Venice’s problems have been used as a pretext to invoke empty rhetorical formulas of preservation, while actually allowing private interests to rob the city blind … Venice is therefore a textbook case of public corruption.”
The saga of Venice’s water wall is one other coastal cities should study as they contemplate a future of higher tides, nastier hurricanes, and more aggressive waves. Epic as it is, the mile-long MOSE is puny compared to the six miles of barriers that would be needed to seal off New York Harbor from the most ferocious storms, a giant hunk of infrastructure that could cost $62 billion — or maybe it’s $119 billion, or $200 billion — and take a generation to build. The Army Corps of Engineers was evaluating that approach, along with a handful of others, as part of a multiyear regional study, until President Trump ridiculed the harbor barrier notion in, yes, a tweet. The New York–New Jersey Harbor and Tributaries Study, or HATS, was abruptly suspended. Evidently, Trump’s fondness for walls didn’t translate to one that might shield the hometown he’s come to loathe from climate change he doesn’t believe in. Tossing HATS aside was negligent, and Biden should revive a broad regional study, but the story of MOSE suggests that Trump’s skepticism about a massive floodgate project was probably on target.
For all its exquisite engineering, MOSE is essentially a stopgap, a $6 billion duct-tape fix that could work just long enough to induce complacency. The fact that it took so long to design and build means that the technology predated the latest science. The barriers top out ten feet above the median sea level, which means that the right combination of storm and tide and melting glaciers could one day send a wall of water sloshing over the parapets. Estimates of how soon or how often that might happen are riddled with variables, but a 2011 UNESCO report concluded that MOSE “might be able to avoid flooding for the next few decades, but the sea will eventually rise to a level where even continuous closures will not be able to protect the city from flooding. The question is not if this will happen, but only when it will happen.”
Venice’s local problems aggravate the effect of global ones. The sea level is rising higher in the Adriatic’s cul de sac than in other parts of the world; the city is dropping slowly but steadily into the wave (by ten inches during the 20th century) because it’s compacting the ancient sediment it sits on and also because nearby industries pumped out groundwater for decades; and immense cruise ships entering the lagoon act like a high-speed version of climate change, pummeling buildings’ foundations with their wakes. The lagoon is fragile because it is, geologically speaking, a baby, barely 5,000 years old. The rivers that feed it filled the bay with silt and would have continued doing so if not for centuries’ worth of human interference, dredging, digging, and reshaping the delta to keep Venice’s canals from turning into muddy ditches.
Alta acqua swamps the streets, November 1966.
Photo: AFP via Getty Images
Venice has always been precarious, and its antique charms can make it an awkward fit with new technology. The city boasts the latest in flood barriers but its homes aren’t hooked up toa modern sewage system, for instance. Whatever comes out goes into the canals, untreated, and festers in the lagoon’s shallows until the tides wash it away into the Adriatic, twice a day. Activating MOSE blocks that flushing action. In effect, it’s the regional-scale equivalent of a backed-up toilet. The result is tolerable if it gets pressed into service now and then, less so if the gates to the lagoon are shut on a regular basis. And they will be. A recent study in the Journal for Nature Conservation determined that if sea level in the Adriatic rises just 50 centimeters (about 20 inches), which is well within the realm of possibility, the barriers would have to close virtually every day.
New York has a deeper harbor and better wastewater treatment, but it faces similar issues. Public projects large (like the LIRR East Side Access) and small (like a branch library, say) creep along for decades, hemorrhaging money. Corruption in the construction industry has been detected on these shores, too. Maybe even more intractably, the city’s 500-mile coastline is an immensely complex tangle of freshwater and brackish waterways, wetlands, cliffs, landfill, islands, and reefs, all of it connected to a far more extensive ecosystem that embraces three states and stretches out into the Atlantic Ocean. Water that hits an artificial wall doesn’t just go away; it caroms off to somewhere else. Which means, for example, that a barrier linking Sandy Hook, New Jersey, to Breezy Point might keep Red Hook and Staten Island dry in a storm but be disastrous for Long Beach and the Rockaways. Monkeying with the rhythm of the ocean tides, which push saltwater 150 miles up the Hudson River to Albany, could wreak untold environmental damage. And focusing on the risk of storms at sea can make it harder to perceive related threats, like flooding rivers, drought, silted-up estuaries, polluted wetlands, and so on.
After Hurricane Sandy in 2012, the Obama administration launched Rebuild by Design, a billion-dollar federal program to come up with a menu of local solutions scattered around New York Harbor. One of those ideas, a system of berms and barriers snaking around lower Manhattan, made its way into the de Blasio administration’s climate plan. But the city can’t defend itself alone. “You have to do a comprehensive regional assessment. Otherwise, every dollar you spend, even on small-scale interventions, is going to waste,” says Henk Ovink, the Dutch expert on water and climate change who ran Rebuild by Design.
Ovink doesn’t think floodgates are wrong, only that they’re oversold. “The idea that a single program will end all problems for Venice or New York is ridiculous. There’s no such thing as the mother of all projects. If you lower the ambition and you ask, can big infrastructure be part of the solution, then the answer is yes, of course.”
The problem is that massive infrastructure projects tend to steamroll doubters, hog attention, and suck up cash. In Venice, MOSE has left little space — or cash — to develop a suite of long-term interventions, fortify wetland conservation, reject the punishing but lucrative traffic of cruise ships, and maybe even develop an alternative to using the lagoon as an enormous cesspool. At the pragmatic end of the spectrum, workers have raised the pavement level of some city streets. At the visionary end are proposals like encircling Venice with a new wall, hoisting the entire city with a giant hydraulic lift, and installing giant pumps to flush out the lagoon. “But these are the kinds of arguments you have over a beer,” Cavaleri says. And now that MOSE is here, Venetians will want to use it, regardless of the incremental financial and environmental damage regular deployment will wreak. The short-term political cost of repeating the December 8 debacle may overtop the long-term consequences of overuse. “A politician who knows that solution A is best but the people want solution B will always go with B,” Cavaleri says.
This year, Venice has gotten a temporary environmental reprieve amid economic disaster. The floodgates made their debut even as the pandemic kept cruise ships away and the cataracts of tourists dried up. But MOSE is a technocratic solution to a psychological issue, the urge to play catch-up with the past. MOSE is an excellent belated answer to the flood of 1966, but it may not help much with the next set of challenges. That’s the tricky thing about disasters: They release torrents of money and provide a jolt of urgency, but both can peter out, and then we are thrown back on our own paltry supplies of foresight. “Do you really need another Sandy?” Ovink fulminates. “This year was the most active hurricane season ever recorded. If all we do is wait for more Sandys, then you give up. Forget about it: You’re walking backwards, responding to yesterday’s disasters.”