Acqua alta: MOSE will fix everything


Now  that I have pounded the subject of acqua alta into unconsciousness, you may be wondering if there are any solutions.   It’s not unreasonable, I guess, to want to suppose that there could be some action(s) that would limit or even prevent water from inconveniently covering your street, even for only two hours.

Certainly many of the articles which continue to appear, year after year  — there must be a workshop in a cave where some crazed Geppetto keeps producing stories on how Venice is being engulfed — tend to make it sound as if   Venice’s health and future happiness depends almost exclusively on keeping the water out.

This is not acqua alta, it's just acqua.

This is not acqua alta, it's just acqua.

So let me urge you, before we continue, to disregard, as far as you can, the drizzle of extravagant statements drenching almost every article about this project.   Such as comments by journalists in love with their clever way with words (“…soaked Bruno Maglis have become more the rule than the exception…” You’ve got money for Maglis — or for  any kind of shoes —  but you haven’t figured out that you can  take them off to keep them dry?   Wow… And by the way, it isn’t true),  or this, by an Italian professor of physical oceanography at MIT:   (“”The gates are really the only solution.”   Really?   The only?), or the  claim that high water really, really distresses the old people.   All the old people I’ve ever talked to are the ones who make the least fuss about it of anybody.    

The good news: There is no lack of useful and feasible ideas on how to limit or prevent high water in the city.   In fact, we have been inundated by a plethora of proposals, many of them simple, easy, not damaging to the environment and cheap.

The bad news: Only one solution has been chosen, and it is none of the above.   Sometimes referred to as the “floodgate project,” this savior is called MOSE.   It is  the biggest, most expensive, most drastic, most irreversible, heaviest-impact-on-the-lagoon-as-a-whole solution  that anyone could have imagined.    I say that because if  there were a solution that could have been more drastic and more expensive,  they would have picked that one instead.  

What is it?

MOSE stands for Modulo Sperimentale Elettromeccanico, or Experimental Electromechanical Module.   It consists of a sequence of a total of 79 steel caissons — boxes, really —  lying on the lagoon floor, which can be raised to form a wall which will block an exceptional incoming tide.

Where is it?  
A view from the Adriatic, looking over the Lagoon and the three "mouths," or inlets, through which the tide comes and goes every six hours.  (R to l): San Nicolo, Malamocco, Chioggia.

A view from the Adriatic, looking over the Lagoon and the three "mouths," or inlets, through which the tide comes and goes every six hours. (R to l): San Nicolo, Malamocco, Chioggia.

The Venetian lagoon is enclosed by a long strip of barrier islands which block the Adriatic Sea except at three inlets (called “bocche,” or “mouths”) through which the tide passes every six hours, coming in or going out.   This exchange of water is crucial to the lagoon’s ecosystem.

How does it work?  

Each of the three “mouths” of the lagoon has been dug to  accommodate a  concrete frame installed on the bottom and sides of the channel.   Attached to this frame, by means of hinges, are the aforementioned 79 metal boxes which normally will lie on the channel bottom, filled with water.    

These diagrams show the steps involved.  Note that one caption states that there 78 of these caissons; there are 79.

These diagrams show the steps involved. Note that one caption states that there 78 of these caissons; there are 79.

If an exceptional high tide is expected (or more than 110 cm [3 1/2 feet]) above median sea level, the water will be pumped out of the boxes  and compressed air pumped in which  will cause them to rise up and form a wall preventing the water from entering the lagoon.   When the tide subsides, these caissons will be filled with water again and they will return to their dormant state on the inlet floor.

When will it be used?

The job of this colossal construction is to prevent — not just any high tide, but  an exceptional one — from reaching the city.    The frequency of a tide of this magnitude is predicted by the city as being  four times a year.  

Therefore, any high water up to 110 cm is going to come ashore just as it always has, and we will continue to break out the boots and merchants in low-lying parts of the city will continue to stow their merchandise and  keep their squeegees at hand to sweep the receding water out the door.   Their keening laments will also be primed and ready to go.

Who thought this up?

As with many large public works, it is the love child of politicians, engineers and  builders.  In this case, an assortment grouped together as the Consorzio Venezia Nuova (New Venice Consortium).    These are not lagoon-huggers.   Many of its members are in  business, often doing the sort of work that MOSE requires.

1973:   The Special Law for Venice is passed, which declares the city’s welfare to be of “preeminent national interest.”  

1975:   The Ministry of Public Works announces an international competition  for project designs which would limit high water.   Five projects are accepted for evaluation.

I will leap ahead here and spare you the year-by-year chronicle of yes/no, he said/she said, did so/did not, claims and counterclaims.   It’s like Jarndyce and Jarndyce.   A full account of this 30-year struggle would be a ponderous assortment of lists of names and companies and government agencies and ministers, environmental organizations, suits and countersuits at every level, from Venice itself to the European Court of Justice in Luxembourg.    By now, the only people in the world who have not been involved in this in some way  are you and me.    

By now, 63 percent of the work is finished.   But the controversy is still very much alive.

Next: Why everybody isn’t excited about it

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Categories : Nature, Problems, Water


  1. Krystyna says:

    So they honestly admit it’s “experimental” – a word which means that they don’t know if it will work and which effects it will have. How touching! (or should I rather say: pathetic.)

    They just had to choose the project where most money is involved, the construction industry is sooo awesome and useful for many, even the mafia loves it.

    This is only the first part of your MOSE story, and my blood pressure is already rising.

    Thans for writing, though, it’s necessary that many people read it!!!