Venice flooding: Is Venice sinking? What is Venice built on? Flood defences, travel advice

Each year between November and March Venice faces rampant flooding which locals call the “acqua volta” – however this year the levels reached record highs in the worst flooding since 1966.

The water reached 6.13 feet above sea level on Tuesday, the second-highest level ever recorded in the city.

Streets became rivers, the historic Basilica flooded, two people have died and Venice’s mayor said the damage is estimated at “hundreds of millions of euros”.

One man died on Pellestrina, one of the many islands which dot the Venetian lagoon, electrocuted while trying to pump water out of his house.

Regional governor Luca Zaia dubbed the flooding “an apocalyptic disaster” and said he was “horrified” by what he was seeing.

Now Prime Minister Giuseppe Conte has said he hopes the flood defence method engineers are focused on will be completed by the spring of 2021.

He said: “Full commitment with Venice. This is a dramatic situation in a unique city and we must be there for it.”

Read More: Venice travel advice: Latest warnings as Venice floods

Venice flooding

Venice flooding: Venice has been inundated with floods during the annual acqua volta (Image: REUTERS)

Regarding the flood defence system being finished soon, Mr Conte said: “We hope so, it is a work on which a lot of money has been spent and is in the final stages, now it must be completed and then maintained”.

Mr Conte said to Venetians: “We are with you and we hope to prevent these dramatic situations from happening again.”

The flood defence system is known as Mose, which is an acronym for ‘Modulo Sperimentale Elettromeccanico’ [Experimental Electromechanical Module].

It refers to the biblical figure Moses who parted the Red Sea to enable the Israelites to flee to safety from Egypt.

The modern-day Moses consists of 78 bright yellow mobile barriers buried in the water that, when activated, will rise above the surface and prevent surging tides from the Adriatic Sea flooding the delicate Venetian lagoon.

Venice flooding

Venice flooding: Entire squares have been filled with floodwater (Image: REUTERS)

Venice Mayor Luigi Brugnaro said: “If Mose had been working, then we would have avoided this exceptional high tide.”

All 78 gates are now in place and engineers are working on the mechanics of raising them simultaneously once tides of more than 110 cm are forecast, with first testing expected next year.

However, there are already issues with the system.

Part of the submerged infrastructure has already started to rust and a source close to the consortium building the mobile dam told Reuters on Wednesday it would cost around €100 million (£85.60 million) a year to maintain — much higher than original estimates.

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The source, who remained anonymous, was confident that once operational, it could defend Venice from tides of up to 3 meters high, well beyond the current record.

But some experts worry the system was not designed to deal with the sort of rising sea waters that recent climate-change models have predicted.

A report here by the U.N.’s science and culture agency UNESCO says Mose was planned on a base scenario of sea levels in the northern Adriatic rising some 22 cm by 2100, but many scientists fear that assumption is far too optimistic.

The 2011 UNESCO report concluded: “The planned mobile barriers might be able to avoid flooding for the next few decades, but the sea will eventually rise to a level where even continuous closures will not be able to protect the city from flooding.”

Venice flooding

Venice flooding: The historic Basilica has flooded (Image: REUTERS)

Venice flooding

Venice flooding: The entire city was once built upon wooden foundations (Image: GETTY)

Are there travel warnings in place for tourists?

As Venice regularly experiences flooding there are contingencies in place for those living and visiting the city.

Raised platforms are in place for tourists wishing to see the historic lagoon, and museums have remained open despite the conditions.

The Foreign and Commonwealth Office has not issued any travel warnings for tourists visiting Venice.

But is Venice sinking?

Each year due to the tidal peaks in the Adriatic Sea, the Venetian Lagoon experiences flooding.

These tidal peaks are due to several factors, including rain levels, rising sea levels, wind strengths and the movement and phase of the Moon.

According to LiveScience Venice is sinking ever so slightly each year – with one study finding the city is tilting to the east.

Years ago subsidence in Venice was recognised as a major problem, as scientists discovered pumping groundwater beneath the city as well as the ground compacting from centuries of building was causing the city to settle.

Pumping groundwater was ended, and studies in the 2000s appeared to show subsidence had stopped.

Venice flooding

Venice flooding: There are no warnings in place for tourists (Image: GETTY)

Venice flooding

Venice flooding: Experts discovered Venice is sinking by two millimetres each year (Image: REUTERS)

However, scientist monitored the elevation of Venice and the lagoons surrounding the city and found in 2012 on average the city is sinking by two millimetres each year.

The subsidence is thought to be caused by the movement of tectonic plates, in particular, the subduction of the Adriatic plate on which Venice lies.

The Adriatic plate is subjecting beneath the Apennines Mountains which in turn is causing Venice to sink slightly each year.

How is Venice built?

Millions of tourists visit Venice each year to take gondola rides through the canals and experience Italy’s floating city.

Venice was built on 118 islands which are located in the middle of the Venetian Lagoon in the Adriatic Sea in Northern Italy.

When settlers arrived in Venice around 402AD they searched for methods of increasing space and creating strong foundations.

So, they dug hundreds of canals and bolstered the banks with wood pilings, using similar wood for foundations.

Thousands of wooden piles were hammered into the mud before the tops were cut off to create solid platforms for their homes to sit atop.

Many of the buildings in Venice today are still standing on 1,000-year-old wood.

Additional reporting by Maria Ortega 

source: express.co.uk