Environmentalists this week expressed fears that Venice would face an increased risk of flooding if plans to expand the Italian city’s port are allowed to go ahead. The city’s port authority wants to develop a huge facility for bulk carriers.
But environmentalists fear dredging the Malamocco navigation channel in the city’s lagoon to accommodate larger container ships will upset its tidal system, increasing the risk of floods.
“The Venice lagoon is a tidal system and deeper channels mean that more water can come in and out with the tide,” said environmental scientist Jane da Mosto, speaking in London at an event organised by conservation charity Venice in Peril this week.
“As the tide goes out, the sediment gets washed out to sea and doesn’t come back. It becomes a deep pool.”
Jane da Mosto
“The tides suck out sediments either side of channel and break down the lagoon bed structures. As the tide goes out, the sediment gets washed out to sea and doesn’t come back. It becomes a deep pool rather than a lagoon.”
Dredging the navigation channel for the existing port has already caused the water level rise that is currently threatening Venice, the charity has warned.
“The lagoon is now more like the open sea and the water level is higher,” said Venice in Peril chairman Anna Somers Cocks. She is concerned that rising sea levels in the lagoon are already starting to damage the city’s historic buildings.
“Venetian houses were built with stone bases as stone is less porous than brick. Water is now above the stone base and rising up through the brickwork. Lots of Venetian buildings have steel tie beams which are rusting as the water rises up through the building.”
The port authority has dismissed Venice in Peril’s claims. It has said that the Mose mobile flood barrier system currently under construction will tackle rising water levels.
However the mobile flood barriers were not designed to counteract damage to the marine environment resulting from increased shipping use.
“Because the lagoon is deeper, the waves are stronger and storm surges are more likely.”
Jane da Mosto
“The port developer said that the mobile barriers will have solved the problem of balancing the lagoon,” said Somers Cocks. “This is not the case − the mobile barriers will just be closed during flooding.”
As the lagoon becomes deeper, the city will become more vulnerable to storm surges and flooding she said.
“Because the lagoon is deeper, the energy of the waves is much stronger and stronger storm surges are more likely,” said da Mosta
Venice in Peril said it would be examining the legal aspects of the port authority’s proposals “with a good Italian lawyer” should they progress.