The Great Venetian Flood of 1966

The Great Venetian Flood of 1966. It was an unprecedented “acqua alta”, with waters peaking at 194 cm; making it the worst flood in its history.

The post includes an illustrated diary, drawn from local reports and notes; of those few eventful days in early November 1966. 

The disaster resulted in an international response for funding restoration and conservation and the planning and development of the MOSE Barrier Project, started in 2003. It’s purpose was twofold: to protect the city of Venice from extreme events such as floods and morphological degradation and to preserve and improve lagoon’s delicate ecosystem.

  • Introduction
  • Historical measures introduced to protect the Lagoon
  • The MOSE Barrier Project
  • Conservation and Environmental measures
  • Acqua Grande – The Story of a few eventful days in Venice 1966
  • Links (internalexternal)


The Great Venetian Flood of 1966 – Introduction



On November 4, 1966, an abnormal occurrence of high tides, rain-swollen rivers of the Venetia plain and a severe Sirocco wind; caused the water levels in the lagoon to rise to a height of 194 cm (6 ft 4 in).

Although Venice is known for its “acqua alta” or high water, especially during the late autumn and winter periods; this particular flood left thousands of residents without homes and caused millions of dollars of damage to property and to works of art throughout Venice.

Although other Italian cities in Northern and Central Italy, such as Florence, Trento, and Siena, all suffered; Venice and the lagoon islands were the most severely affected.

(Note. The median level of the sea in Venice, is not the same as in the rest of Italy. Venice uses the ‘tide-level-zero’ at the Punta della Salute, in the Dorsoduro district; at the southern entrance to the Grand Canal (measured in 1897), where a monitoring station is located. In the rest of Italy, the median sea level refers to the level in Genoa, which is about 23 cm higher).

The city remained isolated for 24 hours, having been unprepared for this extreme type of emergency. More than 75% of businesses, shops, and artisans’ studios, along with their contents, that were either seriously damaged or destroyed completely.

After being neglected and quietly deteriorating after the Napoleonic period; Venice was suddenly recognised as a city in urgent need of investment and planning for flood prevention measures, conservation and restoration.

John Pope-Hennessy, a British art historian, described the full extent of the city’s problems:

It was not just a matter of the flood; rather it was a matter of what the flood revealed, of the havoc wrought by generations of neglect. For centuries Venice lived off tourists, and almost none of the money they brought into the city was put back into the maintenance of its monuments. And that had been aggravated by problems of pollution, an issue of the utmost gravity.”

The solutions to preserving the city and other lagoon’s island for the future; proved to be greater, longer term and more expensive; than could be imagined at the time.


Left: Street markings indicate water levels recorded during episodes of the most extreme acqua alta; most notably the 1966 worst flood on record.






From the 14-15th centuries onward, Venetian authorities had introduced projects and measures to protect the lagoon’s environment, ecosystem and the population; as well as their physical security from invaders and pirates.

Such measures included;

Diversion of major river systems feeding into the lagoon from the Venetian plain; to prevent river silt from accumulating and blocking the lagoon’s deep-water channels and the islands canal systems, especially in the northern lagoon. This silting-up led to malarial outbreaks and depopulation.

Protection against rises in mean sea-water levels and subsidence of the lagoon sea-bed. These factors led to groups of island, especially in the northern lagoon, disappearing under water.

Creation of artificial islands in the lagoon.

Limited and controlled the pumping water from the water table from wells.

Measures to control and limit, the settlement of the building foundations.

Measures to control pollution especially from the Venetian plain, Mestre and Port of Marghera.

Raising of island embankments and quaysides. Paving of walkways.

Introduction of more effective lagoon-dredging programs, creating and maintaining deep-water channels.

Restructuring and enlargement of the three inlets to the lagoon. Building of sea-wall defence systems along the seaward side of the southern lagoon barrier islands (Lidi). Erection of beach and outer sea break-waters, to control sand erosion and deposition on the beaches and on each side of the three inlets to the lagoon.

Planning and development of the MOSE Barrier Project, started in 2003.

(Note. It should be remembered that in the development of Venice and other lagoon islands, millions of resinous timber poles were used as piles, to support the buildings and embankments. This resulted in massive deforestation of the Venetia region, as well as from Croatian and Dalmatian coastal areas; affecting soil stability and water retention).



To safeguard Venice from the flooding at high tide, the MOSE Barrier Project was launched in 2003, designed by engineers at Fiat and built across the three lagoon entrances. Their purpose was twofold: to protect the city of Venice from extreme events such as floods and morphological degradation and to preserve and improve lagoon’s delicate ecosystem.

The following proposed actions were:

  • Recreation and protection of salt marshes to safeguard the natural habitats and to guarantee the essential ecological biodiversity in the lagoon.
  • Reconstruction of (new) beaches and coastal dunes and construction of outer breakwaters to defend from sea storms and stop the erosion.
  • Raising of quaysides and public paved zones in the lowest parts to defend urban centres from floods.
  • Improving the water and sediment quality by isolating polluted land from the canal shores in Porto Marghera and from dumps and by creating special wetlands between the mainland and the lagoon, to filter the water.
  • Installation of mobile barriers at lagoon inlets to protect against floods.

The control and management of the system takes place from the control room at Arsenale Nord and is also an information and visitor centre.

You can visit it as an individual or as part of organised groups and schools. If you want to understand the project and the complexity, it is certainly worth a visit. It is open on weekdays (Monday to Friday) from 9.30-17.30. Check times.

Subject to much delay and cost overrun, the project finally came to completion in 2018 and entered its testing phase.

Puntomose Visitor Centre website 

Information on the Mose Project and the organisation 



In response to the flood disaster, funding and assistance came from all across the globe; as the tragic event reminded many of the need to preserve Venetian art and architecture.

Major funding was received from:

United Nations Educational, Scientific and Cultural Organization (UNESCO)

The Private Committees for the Safeguarding of Venice (ACP)

Other organisations, initiated efforts to help Venice such as:

Save Venice Inc.

Venice in Peril Fund

World Monuments Fund

Further to the above, there were many other more local initiatives, both official, general and for specific causes; that have been set up to help Venice and the Venetians.

It also really helps local Venetian artisans and shops, that were impacted (and still are during extraordinary high water); by buying their products in person or online.



(This diary of events was partly based on an article by Giulio Obici, journalist at Paese Sera, and the notes from Pellestrina police commander Giovanni Cester).

On November 4, 1966, the city of Venice woke up to its biggest nightmare. The largest flood in its history reached a level of 194 cm above median sea level and covered almost the entire city.

The tide remained for 22 hours above 110 cm and for about 40 hours over 50 cm. It created a lot of damage in the historical centre and other lagoon islands.

Left:The gondolas in the Bacino di San Marco are washed away (© Comune di Venezia Archivio della Comunicazione – photographer Borlui).




November 3

Venice and the northern part of Italy had been suffering from a rainstorm and a strong sirocco wind (a dry wind from the south) for several days. The Piave, Brenta and Sile rivers can no longer swallow the excessive water and are now swelling the Venetian lagoon.

The exceptional combination of tidal waves, the full moon, a drop in the barometric pressure and strong winds is the forerunner of the upcoming, yet unpredicted disaster.

At 10 pm, a high tide floods the city of Venice. Usually, at a ‘normal’ acqua alta; the water has enough time to flow back out of the lagoon, before the next flood arrives.

Left:The Biblioteca Marciana during the acqua granda (© Fondo Borlui c/o FAST- Foto Archivio Storico Trevigiano della Provincia di Treviso – Italia).




November 4, early morning

Following the astronomical rules, the water should have started to retreat at 5 am. However, due to the extreme flood and the continuous rain, the lagoon can no longer swallow the excess of water. The water level increases, as does the intensity of the southerly wind. This is a first omen for the double high tide.

Electricity, phones and gas go down in Venice. The residents wait and pray, that the second tidal outflow in the evening will bring consolation. In Pellestrina, the lower parts of the island start to be flooded.

Left: The walls around Pellestrina, can no longer protect the island from the high-water level (© Comune di Venezia Archivio della Comunicazione – photographer Fondo AFU).


November 4, late morning

The situation on the lagoon islands gets worse. A strong wind blows, rain keeps falling and waves of 20 metres high fall on the coasts and break the barriers. Inhabitants call for help from the mainland and flee the islands.

The dams in Portosecco and San Pietro break. Muddy water flows through a hole of 200 metres in the wall at Brasiola and creates channels on the island. Officers get ready to evacuate the complete island, before it disappears in the lagoon.

Left: Around noon, the Via Garibaldi in Castello is flooded. (© Comune di Venezia Archivio della Comunicazione – photographer Fondo Cerulli Gianfranca).



November 4, early afternoon

The phone lines break down in Pellestrina, which is now isolated and completely on its own. The water of the lagoon covers the whole island and the situation is terrifying.  Civilian volunteers inspect the area by boat. Gardens and roads can no longer be seen. The water touches the ceiling of the first floor of houses and people wait for rescue on the rooftops. It is hell.

The other lagoon islands face the same terror. The crops and the livestock are washed away from the vineyards and fields of Cavallino, which are completely destroyed. Sant’Erasmo disappears under waves of 4 metres and furniture floats outside the houses. Boats drift in Burano and hundreds of bathing booths are destroyed by the power of the water in Lido.

In the historic centre of Venice, the water level on the Piazza San Marco reaches 120 cm and up to 150 cm in the Palazzo Ducale. The water in the streets is now polluted with oil leaking from boilers and with other garbage. It starts to smell.

Left:The bathing boots in Lido are completely destroyed (© Comune di Venezia Archivio della Comunicazione – photographer Fondo Cucchini Gabriella).


November 4, late afternoon

The rescue boats from Venice arrive in Pellestrina around 4 pm. More than 4,000 inhabitants are evacuated, while the others seek refuge in houses with multiple floors.

It gets dark in Venice while the residents wait for the second and final outflow of the day. They pray that this one will withdraw the water from the city.

Left:The Riva degli Schiavoni is no longer visible below the water (© Comune di Venezia Archivio della Comunicazione – photographer Fondo Boscaro Matteo).




November 4, early evening

Finally, there is a first positive sign at 17.50 pm. The sirocco wind from the south changes direction and turns to the west. It still blows fiercely, but the water level in the lagoon gets back within its limits. Pellestrina is safe.

The second tide of the day reaches the historical centre of Venice. At 6 pm, the reference point at Punta della Salute measures 194 cm, the highest level of the acqua granda.

Left: The Canal Grande exceeds its limits at Palazzo dei Camerlenghi and the Rialto bridge (© Comune di Venezia Archivio della Comunicazione – photographer FAI)


November 4, evening

Pellestrina is almost deserted. The families have been assembled in barracks at Lido, or found shelter with friends and family. 700 people were admitted to the Hospital al Mare.

Around 9 pm, the water withdraws with strong power from the historical centre of Venice. The first signs of the incredible damage become visible: a blackish streak on the walls of houses from the fuel oil; chairs, mattresses and garbage everywhere; pigeons and dead rats in every corner; desolation in the ground floor houses.

A parade of little flames starts to fill the streets in Venice. The inhabitants inspect the destruction; while at the same time thanking God that the worst part of the nightmare is over.

Left: Any vessel is good to sail on the water at Campo Santa Fosca (© Comune di Venezia Archivio della Comunicazione – photographer Fondo Fornezza Gianni).


November 5

At dawn, the city reveals its wounds after the catastrophe. The acqua granda, demolished more than 75% of the shops, flooded all the houses on the ground floor, damaged almost all workshops, deteriorated an enormous amount of books in libraries, destroyed goods in warehouses, furniture in homes and a lot of artworks.

The walls protecting the islands in the Venetian lagoon, collapsed at approximately 10 points over a total length of 680 metres; while others are damaged or cracked.

Another major drawback is the suspension of the food supply. The water and the lack of electricity made ovens and refrigerators unusable and destroyed all the food kept on the ground floors of the houses. The human crisis is not over yet.

Left: The walls of Pellestrina are severely damaged (© Comune di Venezia Archivio della Comunicazione – photographer AFU).




It takes more than a week to solve the problems of lighting and garbage. 450 people are employed for garbage collection, while teams of specialists use solvents to dissolve the oil slicks in the canals and to clean the black patina on the buildings and monuments.

On December 2, one month after the flood, the UNESCO launched an appeal for international solidarity, to help Venice with the repair of the damages and the restoration of its cultural heritage.

As a result, several international committees were created under the umbrella of the UNESCO World Heritage Centre. Many still exist to preserve the history of Venice. Since 1966, they have restored more than 100 monuments and 1,000 works of art; from the San Marco Basilica and Palazzo Ducale to smaller churches and palazzi.

To safeguard Venice from the flooding at high tide, the Mose Project was launched in 2003. The goal of the project was twofold: to protect the islands in the Venetian lagoon from the high water, while maintaining and restoring the delicate ecosystem.

The project was originally due to be finalised in 2011. However, legislative and financial problems and scandals have led to a huge delay and significant increased costs. The project was not finished until 2018 and the testing phase is just about complete today.

Left:This hairdresser continued his job during the acqua granda at San Giacomo dell’Orio (© Comune di Venezia Archivio della Comunicazione – photographer Fondo Francescatti Francesco).

The 2016 celebration of the 50th anniversary of the acqua grande, was a major event in Venice. The City of Venice appointed a task force to organise several events, to commemorate the great flood of 1966.

One example is the opera ‘Aquagranda’ (Latin spelling) at the Teatro La Fenice, which was composed by Filippo Perocco. The inauguration was played on November 4, exactly 50 years after the tragedy. It tells the story of two fishermen on  Pellestrina island. A copy of the book “Acqua Granda, il romanzo dell’alluvione” by Roberto Bianchin, was used as inspiration of the opera.

The Biblioteca Nazionale Marciana organised the exhibition “Venezia 1966-2016”, with stories and pictures from the archives of the city of Venice. It focussed on the acqua granda of 1966, but also on the restoration of the cultural heritage. The exhibition ran in the Sale Monumentali, from October 28 until November 27, 2016.



Above: Mose Barrier Project. The western gate at the Lido inlet development, coming towards completion; showing the raised barrier.



LINKS (internalexternal)

I have been developing stunning new composite imagery of Venice, that offers a new visualisation of the city. They include images taken, during or on the subject of “acqua alta”; that really fire the imagination. Here’s just one below.

Depicting Venice – Ian Coulling

Depicting Venice 2 – Ian Coulling


Acqua Alta and the MOSE Project

The Venetian Lagoon and its Ecosystem

Back to the the Blog Post page

For a complete picture of the 50th anniversary events.

The Mose Project website




The Great Venetian Flood of 1966    The Great Venetian Flood of 1966    The Great Venetian Flood of 1966

The Great Venetian Flood of 1966    The Great Venetian Flood of 1966    The Great Venetian Flood of 1966

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