It’s not just the buildings — even the canals are getting big repairs.
Simple, but effective, this is how they removed the mud in 1956. This is “dry” dredging, during which a section of canal is blocked by temporary barriers and the water pumped out. If you need to repair foundations of canal-side structures, this is your only option. I really have only one question and that is why are the men wearing white?And this is “wet” dredging, or scavo in umido. They’re here to deepen the canal by removing metric tons of mud — the foundations will have to wait to be checked some other time. Here one man with a mastodontic machine is doing the work of ten or 20 men years ago, except that years ago wet dredging didn’t exist. Progress.
There are roughly 150 canals in Venice, which might sound like a lot, though you probably have many more streets where you live. But whatever they’re made of, streets require maintenance. And often — make that quite often, in Venice — maintenance is conducted only when it has become absolutely necessary.
Canal-beds here are made of mud, and the movement of the tides, plus the thrashing of motorboat propellers night and day, tend to make the mud move around. Sometimes the waves (underwater force of) push it to the sides of the canal where it accumulates, blocking any drains that might be emptying from buildings; the blockage causes the material to build up and over time the chemicals in the material damage the building’s walls. So the mud has been transformed from a water problem to a land problem, and sometimes is the signal that it’s really time to deal with it.
Or the the mud swirls around, carried by the water to wherever the force of the waves diminishes, at which point it eventually drifts downward and is deposited on the bottom. When this process reaches the point where there is no longer enough useful average depth to the water, the dredgers are called in. Just think: High water means that many boats can’t pass under certain bridges until the tide turns, but low water can mean that boats can’t pass at all, bridges or not. This is not a happy situation if the boat in question is an ambulance, or belongs to the firemen. So yes. In your town your roads have potholes. Here we have mud.
One morning in late November, we discovered that dredging of our canal, the rio de Sant’Ana, was imminent. Many copies of the official notice were taped to the red and white striped security tape strung along the pilings. Everybody stopped to read, especially people like us whose boat is in the foreground, therefore directly in the path of danger.Here’s what it comes down to: “Move your boat, we need space so we can dredge between November 15 and December 17, or whenever we finish the work.” Like everybody else on the canal, we had to move our boat somewhere else, which wasn’t a problem. And we soon discovered why the decks, so to speak, had had to be cleared; the dredge would have splintered our little watercraft to kindling. For lots of others, though — for the people who use their boats for work — points 2 a and b were more problematic than where to park it. “From 7:00 AM to 6:00 PM on Monday to Friday, all boats, either by motor or oar, are prohibited from passing this stretch of canal. Emergency and public service boats that have a need that can’t be accomplished by any means other than passing this canal are authorized to pass here but in any case must reach an agreement with the dredging company.” Do not even think about inconveniencing the dredges, this operation costs real money and it needs to get done on time.The next to last holdout moved his boat a few hours after I took this picture. Maybe he noticed the two big dredges ready to start work the next day.As I said, waiting on the other side of the ponte de Sant’Ana to start work, which they will just as soon as the tide goes out just enough to allow them to pass under it. If there is anyone who checks the tides table more than I do, it must be the operators of “Valerio”, the big green dredge, and “Zio Mario” (Uncle Mario), the smaller blue one.Dredging the canals ought to be like painting the Forth Bridge, i.e. continuous. Yet years, sometimes decades, can pass between interventions. Why? (checks notes) Yep: money again. This map announces the conclusion of the canal-dredging program in the 30 above-listed canals. To be fair, dredging the remaining 100 clogged-up canals, at 150,000 per canal, is an impressive line in the city’s future budgets. Frivolous note: I’m sorry to see that I missed the work in the only canal listed here for Castello because it’s a really narrow canal and it would have been fun to see what sort of machine could have gotten in there. Guess I’ll have to wait another 30 years for my next chance.This perspective shows the importance of the accuracy of the tide forecast. Of course the hydraulic arm lies down flat, but there’s the little factor of the deckhouse.
Yes, Uncle Mario did his part.They eventually were working the whole canal together. Here they’ve finished for the day; you can see that Uncle Mario is backing up, stirring up more mud for tomorrow.A good day’s work. Back for more tomorrow. If I had time, I would seriously find someone to tell me how they knew when the job was finished. Metric tonnage of sediment? Strictly by the clock? Fuel consumed?
They were as good as their word: On December 17, they departed, and on 19 we rowed our little boat back to its mooring. When the weather is cold, the water is usually extremely clear, and I can tell you that we could see the bottom of the canal by the wall, and it was definitely deeper. Of course, as always, we’d have to measure it at low tide to know how much deeper it was, compared to two months ago (at low tide). But keeping in mind that now, and for the next month, the lagoon is prone to exceptional low tides, that would also be deceptive.
But the saga continues; dredging is far from over. Via Garibaldi is a rio tera’ — “earthed-in canal” — but not literally filled in, as you might have innocently imagined, because a large culvert was installed beneath the pavement to allow the tidal flux to continue its useful work of fluxing. And over the years the tide had deposited mud in this culvert, too. A filled-in culvert is just as bad as a clogged-up canal.
Conclusion: Considering a new career? Give some thought to dredging Venice. Just regard it as the Humber Canal of cities.
Via Garibaldi is approximately 345 meters long (1,100 feet). That’s a lot of canal to suck dry.The view from the riva dei Sette Martiri onward toward the end of the line at the vegetable boat is impressive. The white barriers snaking down via Garibaldi are guarding the many tubes.The intermittent rectangular interruptions are crosswalks.
This is what’s happening: “Intervention of refurbishment of the sewer network damaged by the high water” — oh, you mean the one two years ago? What’s your hurry? — “and removal of mud in Rio Tera’ Garibaldi.”As you see, the underground canal is getting to be in a tight spot. Opening it more generously will be appreciated by those who have been inhaling that unmistakeable biological aroma at super-low tide. In case you think that just filling in the canal would be a better idea, you should know that a few years ago they did exactly that in a small canal in Cannaregio. It wasn’t long before the residents were up in arms because the tidal flow was blocked and stench ensued. The city had to pay to open it up again.Here you can just make out the top of the street’s arched support. At extremely low tide, which will be here soon, you can see the bottom inside. A bottom which will eventually be much lower.End of the white fences. Let the pumping begin!I’d never given any thought to where this manhole cover might lead. Now I know.The pump is seriously ready to work, moving that mud out of the dark and into the waiting barge. But ask not for whom the mud tolls, because the mud will be back.
