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Delayed Mose defence 'would have prevented' Venice flooding

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The delayed Mose flood defence scheme would have prevented current floods in Venice, according to the city’s mayor. 

Venice is currently flooded following storms in northern Italy which have so far claimed 11 lives. 

The city’s mayor Luigi Brugnaro claims that the flooding could have been avoided had the city’s flood defence scheme – first scheduled to have opened in 2011 – been fully operational.

He said that the lagoon flood defences, the Modulo Sperimentale Elettromeccanico (Mose), would have prevented the inundation.

On Monday, flooding in the city peaked at just over 1.5m. The Mose barrier is planned to shut when tides rise to 1.1m.

Venice maps

Venice maps

Location of Mose flood defence

The project is long overdue, but has been hit by cost overruns and corruption scandals and has attracted local opposition. 

Paolo Lanapoppi of Italia Nostra Venezia, an NGO opposed to Mose, told Plug-In magazine that the project is inheridly flawed, cannot protect the city and may even collapse.

“We have serious doubts. A very serious engineering firm, called Principia has concluded that at the present state of scientific knowledge it is not possible to predict with certainty the behaviour of the movable doors under certain heavy weather conditions,” he said. 

“It could be that they would enter a state of bad resonance and substantially collapse.”

In 2014, over 30 people, including the then Venice mayor Giorgio Orsoni, were arrested following a three year investigation by Italy’s tax office the Guardia di Finanza. Charges included corruption, illicit party financing, and tax fraud totalling $6.8bn (£5.3bn), according to Reuters

Orsoni was accused of accepting illicit funding totalling $635,000 (£498,000) from the consortium behind Mose and was forced to resign after being handed a four-month suspended prison sentence. 

The former president of the Veneto region, Giancarlo Galan did received a prison sentence.

The costs of the Mose project have spiralled from $1.7bn (£1.33bn) at its conception to £4.8bn by 2017. 

Even this forecast may be ambitious, as an extensive investigation in 2017 by newspaper La Stampa revealed that use of different steel types  resulted in the barriers that have been deployed suffering from advanced corrosion on the lagoon bed. Gates awaiting deployment on the harbour-side are also rusting, even though they have a corrosion resistant coating, the report says.  

An additional £622M will be required to repair the corrosion damage, and a further £93M to maintain the barrier each year.

Mose flood barrier factfile: 

Then prime minister Silvio Berlusconi initiated work on the Mose project in 2003. The project which comprises a chain of underwater flood barriers designed to protect the city. 

The 72 flood gates are 30m long and 20m high, and up to 5m deep, and each weighs 300t. 

The gate housing blocks vary in size. The largest is 11.5m high, 60m long and 48m wide. The smallest are 36m wide with the same height and width dimensions.

When the gates are filled with water, they sit on the bottom of the sea, but as sea levels rise, they will be pumped with compressed air, the added bouyancy rotates them into position, closing the entrance to the lagoon. 

Verona based consultant Technital, decided early on to split the northern lagoon entrance channel in two with an artificial island.

Four lines of gates are needed in total, one each for the two southern inlets and two in the northern inlet, the closest entrance to the cluster of islands making up the old city.

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Readers' comments (1)

  • Major Venetian floods, such as the current one, are the result of rainwater discharge into the lagoon as well as tidal surge so the functionality of the Mose barrier is questionable. Also Venice continues to sink. Probably the only long term solution is to raise the city using fracking technology as explained here http://beckettrankine.com/raising-venice/

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