Venice - Having a splashing time, wish you were here

Huge swathes of Venice lay submerged yesterday after the worst floods to hit the city in more than two decades.

High winds and days of heavy rain raised the level of the city's lagoon to more than 5ft above its average height, stranding sightseers and residents and prompting the mayor to issue a stay-away warning to tourists.

Elderly people were carried to safety by firefighters as sirens blared and homeowners and shopkeepers used pumps to bail out the waist-deep water. Such was the severity of the flooding, the duckboards and pontoons which normally cope with Venice's high tides floated away.

The landmark St Mark's Square was among areas submerged under a metre of water after the sea level topped 156cm, well beyond the 110cm flood mark.

The flooding, the highest acqua alta since 158cm in 1986, has reignited arguments over how the historic city in northern Italy can fend off the increasing threat of rising sea levels. Work is under way on a flood defence system, but rows over its impact on the environmental stability of area have led to lengthy delays.

Yesterday, Massimo Cacciari, the mayor, urged people to stay indoors, and appealed to those planning a trip to "think again". Though the water was receding after a change in wind direction, further bad weather is forecast.

The plight of Venetians was compounded by a national transport strike which affected the Venice vaporetto, or water bus service.

Laurence Llewelyn-Bowen, the interior designer and television presenter, in Venice on a shopping trip with his wife, described his hotel lobby as "like a swimming pool".

He added: "We found probably the only caf that's open in Venice. About 80 per cent of the people there were British. We were all drinking brandy. There was a Blitz spirit."

One shopkeeper said: "It all happened so quickly – within 20 minutes we were up to our waists in water."

The highest flood level ever recorded was 194cm in 1966. But high water levels of 100-130cm above sea level are fairly common in Venice, which is built on a series of small islands. Flooding, experts warn, is on the increase due to silt deposits raising the floor of the lagoon and the effects of global warming.

In 1900, St Mark's Square flooded ten times a year but now it floods as many as 60 times a year. The city is said to have sunk by 10cm during the 20th century, and the rate is increasing.

The Italian government has spent more than 3 billion on a flood defence system similar to the Thames Barrier. However, its installation has been slowed by controversy over claims it affects the area's stability.

Yesterday, a spokesman for the council which runs the Venice Tides Centre said the high water level had peaked at around 10:45am and that minor flooding was expected today.

BACKGROUND

VENICE is not the only city whose long-term future is under threat due to rising sea levels.

The Worldwatch Institute, an independent research organisation that promotes sustainable development, warns that of the 33 cities projected to have at least eight million residents each by 2015, some 21 are coastal cities that will have to contend with the impacts of rising seas.

One such city is Bangkok, which sits 3ft 6in to 5ft above the Gulf of Thailand, although some low-lying areas are already below sea level.

The gulf's waters have been rising by about a tenth of an inch a year, about the same as the world average. But the city, built on clay rather than bedrock, has been sinking at a far faster pace, of up to 4in annually.

In Mexico City, meanwhile, land has subsided more than 23ft since 1900 and is still dropping up to 1ft 4in a year.

Other cities under threat according to Worldwatch include New York, Los Angeles, Buenos Aires, Rio de Janeiro, Shanghai, Tianjin and Tokyo.