Venice holds back the water for first time in 1,200 years | Hacker News Reader

Venice holds back the water for first time in 1,200 years

cnn.com

240 pointspseudolus69 comments

The photos that accompany this article don't give justice to the sheer scale of the barriers -- they look pretty small in most photos, especially because it's hard to get a sense of scale against the water.

Here is a better bird's-eye view:

https://www.mosevenezia.eu/multimedia/#prettyPhoto[108475f7b...

And this shows how gargantuan a single element is:

https://apnews.com/article/3b29dc70f308d93b633e2dc38c7acead

With people to scale:

https://en.wikipedia.org/wiki/File:Sezione_paratoia.jpg

And how it works. It's not gigantic hydraulics or pistons, but rather they pump compressed air inside of them to make them buoyant:

https://en.wikipedia.org/wiki/File:03_movimento_paratoie.jpg

Finally, the 3 locations:

https://www.industrytap.com/wp-content/uploads/2013/01/MOSEp...

It's so much more impressive when you finally get a sense of how they work and their scale, which news articles rarely do.

With respect, those pictures you posted fail to capture the scale you elude too. Pictures of structures in my city look equal in magnitude

One element is 20x30 meter, so as "big" as this building is high: https://commons.wikimedia.org/wiki/Category:Edif%C3%ADcio_Lo...

Thank you for the added imagery, I just love feats of engineering like this.

Coming from rural Australia and having moved out into the world, the scale of some things never ceases to boggle my mind. I am so used to things being too hard or costly to do. Not to diminish the things we do accomplish in Aus.

A really simple example of this is bridges. I remember seeing a bridge in Japan with what must have been hundreds of pylons in the middle of the city, dancing past buildings, over intersections and under other bridges. In Aus, I feel we just wouldn't do it.

Australia unfortunately has a lot of catching up to do infrastructure wise. Every project becomes politicised, initially under funded, ends up going over cost, key roles get outsourced. We missed the infrastructure boom that other countries had post WW2 so now we look like we're falling behind. Motorways that the US had in the 70s are only just being constructed in some of our major cities.

Totally agree. On the other hand, it does put us in the unique position of being able to learn lessons from mature infrastructure projects from around the world. Hopefully we can be more effective because of it, but we'll see!

Your new infrastructure will still be cheap to maintain while the rest of the world lags in maintenance. Aus will catch up.

"Against all odds, it worked"

No, they employed actual engineers and a sizable budget. There was no guesswork on whether it is going to work. The physics is very strong and the water flows and level changes have been monitored precisely for decades giving engineers enough data to build robust protection.

So, you're saying, that there was a 100% probability of it working?

Not 100% but much much better than "against all odds".

I think you're under-rating how uncertain these large scale engineering projects are in real terms. Yes, of course, when the project has the attention and the funding and the time and the political support it needs it will work! I know that and you know that. But if you're waiting for, say, a high-speed rail in California, or the 2nd avenue subway in New York, or in New Orleans[1] you might be forgiven for being skeptical.

I was struck by the same line, but for the opposite reason. I think it's rare, today, for large scale projects to work out exactly as expected. These projects, even when executed well, require enormous amounts of money and time and skill to pull off. Many things can sabotage them. I don't blame people for being surprised they worked.

[1] https://www.scientificamerican.com/article/after-a-14-billio...

I don't think the technical issues are the cause of the uncertainty in large scale projects, it is the political, right of way, and permitting issues that make it impossible to plan and execute a project. Out in the middle of the water there must not have been many people to oppose the project! And everyone in Venice was happy not to be flooded out.

I've designed and programmed control systems for about a dozen similar inflatable dams although the largest one I worked on was miniscule in comparison at 3m tall and 25m wide. My projects used a product with kevlar bladders with stainless panels on top rather than pumping air in to enormous metal enclosures.

There must be one hell of a compressor station to provide the volume of air required to get the water out of the gate panels in venice. And since the use of the flood protection will probably coincide with shit weather I bet they have diesel standby generators to power the whole operation.

The original statement never suggested the odds were poor because of technical reasons.

The project has been ongoing in some form from the 60s and 70s.

I think we could talk about how much to trust internally generated assessments of how successful an ambitious engineering project will be. Projects have been badly designed by well meaning engineers before.

That said, I wasn't trying to say that the problem was technical in nature. It's that a sound technical design (and competent construction of that design) is only one part in a much larger problem set. A solution that the people who are paying for it don't want (for whatever reason) is unlikely to succeed. The Wikipedia article for MOSE (the Venice anti-flood system) lists many lawsuits worried that it's insufficient, will damage the environment, etc[1].

To me, this suggests that it may harm projects to leave it at "the engineering is fine." The engineering may actually be more flexible than other constraints. It's possible that the optimal design for a perfectly supportive environment may be less well suited for the world that exists.

[1] https://en.wikipedia.org/wiki/MOSE_Project#Criticism,_corrup...

There was a ton of people opposing this project for decades on environmental grounds ("it will disrupt sea life"), funding grounds ("it will cost too much forever"), corruption grounds ("organized crime will eat all the money") and engineering ("this won't work reliably, will break soon, will be obsolete..").

It was a heavily politicised issue and it's actually mildly surprising to see it finished and working.

Flooding is somewhat of an existential crisis for Venice. If they don't get it figured out the money will stop flowing and they'll be underwater economically as well as literally.

Contrast with NYC and SF where people just keep pouring in the dollars no matter how late the trains are or how rampant the petty crime is. Those cities won't pull their collective heads out of their collective asses and figure out solutions until the problem reaches existential proportions.

There seems to be only two ways big infrastructure projects get done in the western world these days. The first is a boondoggle graft laden handout to buy votes (e.g. the Big Dig) and the second is to ignore the problem until you can't anymore and then you finally get serious and implement some solution that has been on your radar since forever (e.g. MOSE).

There is a ton of expertise with this kind of things, in particular the Netherlands. There's a lot of science done to back all of that engineering up. Yes, it is an accomplishment in its own right, but no, its not miraculous, but down to decades of diligent research.

The primitive methods used in New Orleans have always been a mystery in Dutch professional circles.

Others seem to disagree with you:

"Venice and MOSE: story of a failure. After scandals and cost overruns, will the flood barrier project be dismantled? Inspections show that many of the gates have been eroded by sea-life. And the hinges are at risk of cracking" [1]

"But the project, known as Mose, has been plagued by the sort of problems that have come to characterize many major Italian construction programs -- corruption, cost overruns and prolonged delays... The good news is they will discover that the building work is almost complete. The bad news is no-one is sure how it will cope with the growing phenomenon of flooding and whether it might prove too little, too late." [2]

"MOSE Project: Criticism, corruption, and court cases" [3]

[1] https://www.lastampa.it/esteri/la-stampa-in-english/2017/10/...

[2] https://www.reuters.com/article/us-italy-weather-venice-mose...

[3] https://en.wikipedia.org/wiki/MOSE_Project#Criticism,_corrup...

"Against all political odds"

It took 5x longer than it should have.

That said, it works.

Exactly. This is the equivalent of "Thank God" after a doctor saves a patient, instead of thanking the doctor.

Thank the engineers who had to put up with nearly 40 years of corruption. BTW, the damn thing still isn't done because of politics and corruption, so I wish those engineers all the best.

>The defense system is called MOSE, the Italian for Moses, a name derived from the more functional Modulo Sperimentale Elettromeccanico, meaning Electromagnetic Experimental Module.

Elettromeccanico translates of course to electromechanic, and there is nothing actually "magnetic" in the project.

https://en.wikipedia.org/wiki/Acqua_alta#Countermeasures

As a side note the MOSE is pronounced "plain", while the Italian for Moses is Mosè (accented on the last e).

If it uses electric motors to move things, or relays/contactors, magnetism is definitely involved.

there's nothing "magnetic" in the word "elettromeccanico" which is quite obviously the composition of "elettro" (electro) and "meccanico" (mechanic) :)

Electric current always involves a magnetic field. Law of the universe.

The complaint is about the translation, not the term.

It also involves quantum mechanics, odd why it's not mentioned.

To say it more accurately, a change in an electric current induces a magnetic field.

It's better to translate it as 'electromechanic' (although the distinction between electromechanics and electromagnetism is a subtle one, which I'm not sure translates well) but it's a bit too easy to dismiss electromagnetic because it has nothing to do with magnetism. The term 'electromagnetism' is wrong because it refers to the scientific field of study, rather than the field of engineering. It would also be iffy to call an electromagnet 'electromagnetic', even though it clearly involves both electricity and magnetism.

Also most electromotors will use magnets at some point, if only because it makes it many times easier to generate a reasonable amount of force.

At least they got the right sea (:

Moses — who held back the waters and parted the Red Sea, btw. https://en.wikipedia.org/wiki/Crossing_the_Red_Sea

Related: the Dutch also have some pretty wild stuff. Check out the storm surge barrier protecting Rotterdam and the port:

https://en.wikipedia.org/wiki/Maeslantkering

yup, a much better design that rests on dry land rather than on the sea bed while not in use; reducing corrosion rates and making maintenance a much cheaper procedure.

"Ah, but what about the landscape!" cried the politicos when greasing this pork barrel for their industry friends. Yeah, right... I bet they had the same scruples when they broke ground for Pordo Marghera. SMH

> Ah, but what about the landscape!

Ah but what about the fact that the Maeslantkering closes a canal that is 360 metres wide, the total width of the MOSE is 1.6km...

https://en.m.wikipedia.org/wiki/Oosterscheldekering

The MOSE consists of 3 separate installations for 3 different harbor mouths, so in principle it wouldn't have been that much different from the Dutch scenario.

It's actually four sections, each longer than the entire Maeslantkering.

The Maeslantkering is only one of a series of structures to control the water flow, the Delta Works[1].

The Oosterscheldekering[2] is a much bigger structure, about nine kilometers long with four kilometers of openable sluices that were added after protests against closing off the water way. Similarly gigantic is the 5 kilometers long Haringvlietdam[3].

These projects are quite old, though, so some innovation to water control is always welcome. The system used by MOSE seems to be quite easy to hide compared to the massive steel and concrete structures of the Dutch system. If it turns out there is no penalty to longevity and maintenance, a system similar to the Italian project might just show up in the Netherlands as well.

[1]: https://en.wikipedia.org/wiki/Delta_Works [2]: https://en.wikipedia.org/wiki/Oosterscheldekering [3]: https://en.wikipedia.org/wiki/Haringvlietdam

Venice is a series of islands that is 100% developed.

There is no open dry land, aside for a few small (<1 city block) sized parks.

https://upload.wikimedia.org/wikipedia/commons/3/38/Venice_a...

Sure but a double-digit amount of the entire Netherlands was water, and remains below sea level. Hence the name.

I haven't a clue if it's practical/economical for Venice to build more land, however; without more information, I'll assume their solution is right for them, as the Dutch solution is for the Netherlands.

Rotterdam was almost completely rebuilt after WWII, Venice has been there almost unchanged for about 15 centuries.

It's much more fragile than practically any other city in the World and needs a particular care.

Building modern structures on it (choosing carefully where, since it's built on over 400 islands) would ruin it forever.

“Port of Rotterdam is the largest seaport in Europe, […] From 1962 until 2004 it was the world's busiest port” https://en.wikipedia.org/wiki/Port_of_Rotterdam

Wow

This is petty, but should I believe the Wikipedia article when it says "the barriers are controlled by a supercomputer"?

Unless this is a 1980s-vintage supercomputer, I'm baffled. The barriers' main function is to open or close. Someone needs to assess and predict rising water levels, but a lot of that is surely done by other systems. Add in some speed adjustments and some docking/aligning adjustments to get everything to shut just so -- and it still sounds far simpler than an iPhone camera.

The civil engineering challenge is huge. But I'm not seeing a huge need for the very high end of modern computing power to make it all work.

The citation to the previous sentence (see https://www.dekennisvannu.nl/site/artikel/Rekenkracht-is-mac...) discusses the use of supercomputers, but from Google's Dutch to English translation it's not clear if supercomputer is in contradistinction to the BOS system that controls the barrier, or if BOS was just a lesser type of supercomputer-class controller.

Here's more information on BOS: https://park.org/Netherlands/pavilions/techno/svk/engels/wer... https://park.org/Netherlands/pavilions/techno/svk/engels/wer...

Here's a page describing BOS from the company that built it, though emphasizing it's reliability, not computational power: https://www.cgi-group.co.uk/en/media/case-study/intelligent-...

Maybe it uses a supercomputer to simulate the incoming tide and decide how much water to let in before raising the gate? It seems odd that they'd need more computation power than a tide table and an associated lookup table of setpoints, though.

The thing is made to stop storm surges, not simply the regular tide. Presumably the "super computer" refer to computers predicting the weather, which even these days is a pretty processor intensive thing to do.

Yeah, they might need a feed from the local weather bureau as well. It seems odd to describe that as "powered by a supercomputer", though - unless you'd also say I "used a supercomputer" to decide whether to take the car or the bike on any given day.

From the article: ”Part of the Delta Works, the barriers are controlled by a supercomputer, and automatically close when Rotterdam (especially the Port of Rotterdam) is threatened by floods.”

It’s not the mechanical controller, it’s the decision to pre-activate protection based on prediction (“threat”) of weather conditions and water levels.

The article doesn't explain why the plan is to wait for 110cm of rise to raise the barriers, despite flooding starting at 90cm. Does anyone know the reason? Is it a trade-off with keeping the lagoon open for shipping?

No, as far as I know it's because closing the barriers too often would reduce too much the exchange of water between the lagoon and the sea, damaging the lagoon's ecosystem. So it was decided to use it only when strictly necessary.

My guess would be because it closes off maritime traffic, and they likely have decided on a metric that balances both the needs of the city and traveling boats.

Because Venice is an ecosystem, it's not like the Netherlands that are in open ocean, the lagoon has a unique environment that need to be preserved as much as the city itself.

I grew up a two hours car drive from Venice and have been there for 10 times at least. It is my absolute favourite place to explore by foot, especially off the typical tourist sections. The challenges the Venetians are facing and how they are dealing with them are nothing short of amazing (although Venetians will tell you about municipal corruption).

I can't wait to go there again.

I've been there exactly once, with my wife and our kids. We stayed on the island. We loved it. We avoided the tourist areas during the day. The island just isn't that crowded away from a handful of locations. At night, we had the island almost to ourselves to explore.

Wandering around in the dark alleys was at first a bit unnerving. In any big city, you'd feel unsafe in such locations. But after we realized we really had nothing to fear, we relaxed and just enjoyed the experience.

In the morning, I got up early and wandered to the fish market to watch it get setup for the day.

All in all, a totally great and memorable experience. We enjoyed it as much as Rome.

Florence on the other hand... not our favorite.

Italy was a joy to visit. We hope to go back someday.

Unless you count in people getting their wallet/camera stolen by pickpockets Venice is a quite safe city. The pickpockets will be usually concentrating on very overrun touristy areas so if you avoid those it is as safe as any other North Italian city (which means I'd not be afraid to sleep out on the street with all my belongings next to me if I really had to).

That's a great achievement, given how annoying the flood in Venice is... but it's not all rosy.

Corruption. Overspending. Dubious technical choices.

I would look at the Netherlands as a model for the next place to face a similar challenge.

Agreed.

However, if even Venice can achieve this given the corruption in Italy, then maybe there's hope for our species after all.

I'm always amazed, given how corrupt Italy is - their infrastructure is incredibly advanced. Silky smooth highways and very impressive rail infrastructure.

https://www.theguardian.com/world/2020/apr/08/lockdown-keeps...

https://en.m.wikipedia.org/wiki/Ponte_Morandi

> I would look to the Netherlands as a model

Amsterdam, de grote stad

Die is gebouwd op palen

Als die stad eens ommeviel

Wie zou dat dan betalen?

https://www.dmarge.com/2020/08/amsterdam-new-challenge.html

Every city project should also include anti-corruption “engineering”

> The defense system is called MOSE, the Italian for Moses, a name derived from the more functional Modulo Sperimentale Elettromeccanico, meaning Experimental Electromechanical Module.

lol i get a kick out of articles like this. why not just admit its named after Moses, the biblical figure that split the red sea?

I hope it's error mode is not a mini Tsunami...

it's probably broken hinges and a floating steel caisson. Or the same caisson stuck halfway out of its silted-up resting plate. Or the same caisson unable to erect because the caissons themselves are covered in silt... duh

There was a good TV program about this during construction . Glad it has come to fruition

”It works” is relative and the statement that "St Mark's Square is pretty much dry" is a lie. It is flooded as every year, a friend is just there for a visit and sent a foto. Not knee deep, but more than 15cm. Could have been worse, I guess, but it's still flooded.

The article talks about that: the barriers currently go up when the water level is expected to be 130cm or more (above some mean level, I guess). St. Mark's floods at 90cm according to the article.

When there was a 132cm tide, the barriers went up and St. Mark's stayed dry. The next day, the tide was 106cm, the barriers stayed down, St. Mark's flooded. What was the exact date on your friend's photo? What was the tide height that day?

Did they hire a Dutch engineer? :)

I thought the tides were necessary to flush out the canals (which transport sewage)...

That’s why they built a barrier that, until the time a barrier is needed, minimizes its impact on the tides.

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