Are we ready for the flood?

Mario Pavanini
13 min readDec 15, 2016
Piazza San Marco (Source: Archivio Storico Comunale — Celestia)

Are we ready for this?

Are we ready to lose the inestimable cultural and artistic heritage of one of the most famous and unique cities in the world?

Are we ready to lose hundreds?


The historical center of Venice is composed by 118 islands connected by 354 bridges and divided by 177 canals. The shape and the land on which Venice stands required the solution to various problems in building construction and urbanism of the city, such as the consolidation of the foundations obtained by planting wooden poles in the unstable soil of the lagoon islands. The city, unfortunately, is slowly sinking due to the natural subsidence of the territory and to the sea level rise caused by natural causes, but in latest years mostly by human induced global warming. The Forecasting Center and Reports of Venice Tides estimated in 26 cm (average of the last ten years) the total loss of elevation of the city from 1897 (year of the definition of zero elevation, all values are recorded at the Punta della Salute Venice Station and refer to the 1897 tidal datum point), divided in the following contributions:

  • Subsidence, +12 cm (natural and human causes)
  • Sea Level Rise, +14 cm
The table shows the percentage of flooding connected to high tides. The bar chart shows the ten-year frequency of tides >=110cm. High waters since 1966, the year of the great flood, more than 110 cm have been 191, while between 1926 and 1965 had been 21.

Moreover, Venice is interested by “Acqua Alta”( literally “High Water”, Venetian expression for high tide) the phenomenon of particularly pronounced tidal surges that occur with frequency in the northern Adriatic and with particular intensity in the Venice lagoon, which cause flooding in urban areas of Venice and Chioggia and, much more rarely, Grado and Trieste (North-East of Venice).

Source: Centro previsioni e Segnalazioni Maree

The problem of the flood in Venice now, is more real than ever.

Signs in St. Mark’s square of the “Aqua Granda”(Venetian dialect expression to remember the big flood) in 1966"

Following the flood of November 4, 1966, during which Venice, Chioggia and the other lagoon towns were submerged under a tidal wave of 194cm, the first Special Law for Venice (Law no. 171/1973) declared the problem of preservation of the city “of national importance” beginning a long legislative and technical procedure to preserve the lagoon in Venice and secure an effective system of defense from the sea. While back in 1966 global warming wasn’t included among the factors that lead to the exceptional flood (astronomical influence, meteorological tide, seiche of the Adriatic sea etc.) and action was taken just to stop the pumping from the aquifer responsible for subsidence of the town soil, now it is certainly playing a major role in forecast of future scenarios.

Indeed, two effects ascribable to global warming are the increase of exceptional weather events and the rising of sea level. Therefore it is easy to see how human kind is contributing to the flood of its own cities.

These graphics show the increase of global temperatures and the rising of sea levels (source: AR5, SPM, p. 3)


I reckon that even though I had fun going to school wearing high boots through the flooded city, what I did not enjoy was being awoken during the night from the siren announcing the high tide (imagine owners of ground floor shops), but luckily the government had something in store for Venice.

The Mose project was chosen at the end of a long planning and decision-making process during which the sluice system at the inlets was compared with several alternative solutions. It turned out to be the only work that could meet the specific constraints and requirements: ensure full protection of the area from flooding, do not change the water exchanges at the inlets, no fixed intermediate cells in the canals at the inlets, not interference with the landscape and the environment, no interference with the economic activity taking place through the same openings. The Mose consists of 4 barriers of 78 movable independent gates, each capable of temporarily separating the lagoon from the sea and to protect Venice from exceptional and destructive tidal events, both far more frequent than in the past. The barriers are placed at the inlets of Lido, Malamocco and Chioggia. The Mose can protect Venice and its lagoon from high tides up to 3 meters and a rise of up to 60 centimeters above sea level in the next 100 years.


So the Mose project on paper seemed to be perfect: innovative, environmentally friendly, hidden underwater. Despite protests of environmentalists regarding the impact of the massive project; Even though in 2009 the European Commission-Environment, taking into account the mitigation and environmental restoration adopted by the Italian Government, dismissed an environmental infringement procedure brought to Italy; Despite protests against construction and the fact that operating and maintenance costs would have been at the expense of the Italian government - costs that the associations opposed to the project said would have been much higher than other systems with which other countries (Netherlands, United Kingdom) had faced similar problems - the project finally took off in 2003 (let me remind you the first Special Law was issued in 1973), and the money started to come. A lot of money.

The authority that carries out the work is “Consorzio Venezia Nuova” (born from the union of companies and construction cooperatives, national and local), chosen by the government under the law. 789/84.

From an initial cost of 3441 millions and a completion date expected in 2012, the costs raised by 60% to 5493 millions of euros and the expected date of completion postponed to 2020-21.

The bombshell on MOSE was dropped between 2013, when the Guardia di Finanza arrested managers of the firm “Ing. E. Mantovani S.p.A.” for alleged tax fraud relating to a false billing creation system, and 2014, when the public prosecutor in Venice requested the arrest of 35 people and informed 100 of being under investigation. Pandora’s box was opened. Between the arrested people figured Venice Mayor, Giorgio Orsoni (now dismissed of the charges), the regional minister Renato Chisso, retired General of the Guardia di Finanza Emilio Speziante, the outgoing MEP Lia Sartori and parliamentary Giancarlo Galan (from 1995 to 2010 governor of the region of Veneto).

The most common alleged charges were corruption, tax fraud and illegal financing of political parties. According to the prosecution, the mechanism to get the money was the well established false billing system.

The whole system flaw is in part ascribable to the decision of making “Consorzio Venezia Nuova” the sole-concessionaire of the whole project. In a Corte dei Conti relation on the law 798/1994 we find:

“This provision resulted, since its enactment, in contrast, as well as with the general principles that the EU Treaty establishes in terms of competition, also with the 1971 EEC directive on procedures and award of public works contracts. Moreover, the law enacted the possibility and not the obligation of the use of this form of commitment.”

The Corte dei Conti then is clear in the conclusions of the report:

“The obligation in the Community directives of compliance with the principles of non-discrimination, equal treatment, proportionality and transparency, which is realized through the award of contracts with public tenders, has not yet been observed for one of the most significant works in progress by the Italian State (the MOSE), despite presence of: national laws aimed at overcoming the system of the commitment by private negotiation of the concession in question; a long dispute with the European Commission, resolved in 2002 with a compromise, which partially opened to the market the implementation activities of the preservation of the lagoon and has averted the referral to the Court of Justice by the Commission itself . The exhortation of the Corte dei Conti to proceed with the commitment of the works on the basis of an invitation to tender, which must apply to all the actions still to be developed (2009), with particular reference to those related to the construction of the Mose. The clause of the General Convention, which provides for the possibility of unilateral withdrawal from the administration. The obligation, to set aside national legislative provisions contrary to Community law by the authorities.”

The Corte dei Conti also observed that this “monopoly” is not meant to end with the conclusion of the work. Again in the conclusions:

“Neither the conclusion of the works, scheduled for 2012 (in 2009 this was still the set date, the work will actually be completed in 2018 according to the latest forecast), is to set an end to the abnormal attribution of powers in the hands of the dealer without invitation to tender, since recently, the maintenance work has been entrusted to the same management. It is easy to predict, given the monopoly lasted for over twenty years, it will be difficult, in the future, to find a “different” manager from the same dealer.”

From December 1st, 2014 Consorzio Venezia Nuova is under extraordinary and temporary administration (Decreto Legge 24.06.2014 n. 90 art. 32, comma 1).

Furthermore a number of malfunctioning occurred during the last tests: movable gates not moving because of debris, the rupture of one of them, a flooding and the rupture of a steel door. Additionally, concerns have arisen from the discovery of rust in some of the gigantic hinges (158) which raise the gates. So on top of the white-collar issues it is also uncertain if the project will really work and due to the technical problems already experienced the expected maintenance work and costs (80 million per year) are already scary.

1. Beaches reinforced 2. The intervention on the north pier of Malamocco 3. The intervention on the banks of the Zattere (Source:

It is good to know that not all is bad as it seems. The Mose is not an isolated work, but it is part of Interventions to safeguard Venice and its lagoon, under the Special Law for the Venice General Plan defined as a result of the flood of November 4, 1966. The interventions of the State have interested the recovery of characteristic habitats, such as salt marshes and shallow waters (over 1,500 hectares reconstructed and protected), the securing of landfills and the industrial area of Porto Marghera channels (5 polluted sites and 45 km of shores banks and waterproofed) and protection from storms (46 km of beaches reinforced and naturalized). These represent the most impressive defense program, recovery and regeneration of the environment, that the Italian State has ever implemented. In this framework the Mose defense from high waters along with the actions of defense of the lagoon settlements, which covered more than 100 km of shores and banks, is the last and most important step for the protection of the lagoon territory.

The Italian newspaper ‘Il Sole 24 Ore’ says:

“The point is that the Mose is needed and needs to be done. You can’t do it as the Dutch dams — endless rows of huge concrete pillars that support thousands of square kilometers of steel floodgates that will close the view for generations. Instead the project in Venice has to be invisible. As it looks now, the Venice lagoon is the result of the work of man. If the rivers Piave, Brenta and Sile would still flow into it, the lagoon would be buried and now it would be a stretch of houses, industrial buildings and agricultural areas. The mouths of the rivers have been diverted since the XIV century “freezing” the lagoon for the centuries to come. The great ancient works were the subject of fierce battles, like the one in the 1500ds that divided the waterway manager Cristoforo Sabbadino — he wanted a lagoon open to the waters — and the political Luigi Cornaro — who wanted to drain Venice. Just like back then, today there is an ideological battle against the Mose with alternative projects.”

The Mose is needed to give Venice one more century, maybe, let’s hope that in the future there will be better and definitive technologies. But first it has to be finished and it has to work.

As IPCC report states the Global mean sea level rise will continue during the 21st century, very likely at a faster rate than observed from 1971 to 2010. By the end of the 21st century, it is very likely that sea level will rise in more than about 95% of the ocean area. About 70% of the coastlines worldwide are projected to experience a sea level change within ±20% of the global mean.

High Tide in St. Mark Square (Source:

What is going to happen to Venice meanwhile? Only time will tell us.


As we already saw the Mose itself is a transnational project from the very first phase, where the best engineers showed their projects, to the end (just think that when the European commission dismissed the environmental infringement procedure, unlocked 1.5 billion of European founds). Project was also presented at the UN building. The presentation was part of the event ‘Saving and Preserving World Heritage Cities: Venice and Dubrovnik’, where the two sister cities on both sides of the Adriatic have been confronted on the challenges of preservation of historical heritage in relation to the opportunities offered from mass tourism and the problems posed by climate change.

1. Surge Barriers on the River Thames protect 125 square kilometres of central London from flooding caused by tidal surges. 2. The Oosterscheldekering, one of 13 ambitious Delta Works series of dams and storm surge barriers, designed to protect the Netherlands from flooding from the North Sea. (Source:

Furthermore Mose is part of the “International Network of Storm Surge Barriers”. From mobile dams on the River Thames in London (England), to those on the Scheldt and Rotterdam (Netherlands), with those in St. Petersburg (Russia) and recently in New Orleans (USA), the world already operates many mobile barriers sea defense and the Superintendency Interregional for Public Works of Triveneto is a founding partner. I-STORM purpose is to continuously improve standards of operation, management and performance in order to reduce the risk of severe flooding of people, property and places around the world. Moreover the international network helps the sharing of experiences and the transfer of knowledge on operational and functional management of large movable storm surge barriers in order to optimise the management of barriers by innovative management. This objective is achieved by the organization of a network that serves as a meeting place for Storm Surge Barrier Managers. I wonder what went wrong with Mose. It seems that the particular characteristics that differentiate it from other systems are the ones that are giving the most problems.


The seas of the Earth are rising, a direct result of a changing climate. Oceans temperatures are increasing, leading to ocean expansion. And as ice sheets and glaciers melt, they add more water. As humanity experiences the early effects of a rapidly changing climate, policymakers focus on two primary responses: mitigation, and adaptation, or modifying infrastructure or behavior to adjust to climatic change.

Rising temperatures and sea level, increased coastal flooding and perturbation of weather patterns are among the changes likely to require an adaptive response. Recent projection [Hinkel et al., 2014] found that, absent adaptation, 0.2 to 4.6 of Earth’s population - tens of millions or more - could see yearly flooding by 2100, assuming a 25 to 123 centimeter rise in global mean sea level. Adaptive measures, such as construction of dikes for coastal protection, would bring yearly investment and maintenance costs to $12 to $71 billion by 2100.

Likely a far smaller figure than the cost of the damages that would otherwise be unavoidable.

The Paris Agreement placed adaptation on more equal footing with mitigation in importance and needs, and strives to mobilize increased regional and national support for adaptation along with mitigation.

State of the Climate reports:

“Increasing concentrations of greenhouse gases are preventing heat radiated from Earth’s surface from escaping into space as freely as it used to; most of the excess heat is being stored in the upper ocean. As a result, upper ocean heat content has increased significantly over the past two decades.”

Peak global mean temperature, atmospheric CO2, maximum global mean sea level (GMSL), and source(s) of meltwater. Light blue shading indicates uncertainty of GMSL maximum. Red pie charts over Greenland and Antarctica denote fraction (not location) of ice retreat. (Source: A Dutton / Science.)

Geologist Andrea Dutton at the University of Florida published a paper in the journal Science, in which he found that modest rises in global temperatures of 1–2C in the past led to sea levels rising at least six meters, ranging up to 13 meters.

“Even if we meet that 2°C target, in the past with those types of temperatures, we may be committing ourselves to this level of sea level rise in the long term. The decisions we make now about where we want to be in 2100 commit us on a pathway where we can’t go back. Once these ice sheets start to melt, the changes become irreversible.”

With sea level rising pretty much irreversible adaptation measures are more than necessary. Venice, unfortunately I have to say, is an example of what could possibly go wrong since there is still no certainty about the functioning of the Mose and even if it works it would not be a definitive solution.

It has to be understood what is at stake, what could be lost just because game of powers and money because there is no room for mistakes.

Climate Central has launched its first animated map, Seeing Choices, which allows viewers to see the long-term sea levels locked in by different amounts of carbon pollution, contrasting scenarios of 0°C through 4°C of global warming.

UPDATE 14/11/19

Two days ago, November the 12th of 2019, Venice experienced the highest Acqua Alta after the flood of 1966: a tidal wave of 187cm with winds up to 100 kmh.

the force of the tidal wave inside the historical center of Venice
The historical center of Venice completely flooded.

M.O.S.E. still not in function.

The historical center of Venice completely flooded.

53 years have passed yet nothing has changed.


In the last weeks the city of Venice experienced new tidal waves up to 130 cm.

M.O.S.E. barriers in function. On the left the lagoon (70 cm tide) on the right the Adriatic Sea (130 cm tide).

M.O.S.E. was activated, even if not tested properly. With the city struggling after the economic crisis induced by the floods of 2019 and the pandemic of Covid-19 there was no other choiche for the Special Commissioner of Consorzio Venezia nuova but to use the 5.4 billion euros infrastructure.

M.O.S.E. worked properly — which is great news — but is still missing a plan for the 100 million euros per year maintenance.



Mario Pavanini

Law graduate. Expertise in IT Law, Privacy and Administrative Law.