Venice sinking fast, claims new study

In this story: Mayor disputes evidence Dam project to save city RELATED SITES

VENICE, Italy (Reuters) -- A new archaeological report suggests the ancient city of Venice may be sinking faster than previously thought.

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American archaeologist Albert Ammerman claims that not only has the sinking process speeded up, but a controversial and expensive plan to protect the city from flood waters with moveable dams will not work.

In an article published in the latest edition of the journal Science, Ammerman says the dams would not prevent Venice from sinking, but it was hoped that they would allay the effects of high and flood waters, which are likely to be exacerbated by global warming.

Venice, which rests on millions of wooden piles pounded into marshy ground, has sunk by about seven centimetres a century for the past 1,000 years.

But the U.S. study says that it has subsided 24 centimetres in the past 100 years.

However, Venice's mayor Paolo Costa says the report is inaccurate, although a study carried out by the city authorities concedes it will sink between 20 and 50 centimetres by 2050.

"From a scientific point of view, the conclusions are incorrect," Costa said in an interview.

"The study is based on a very good piece of archaeological research -- it was able to compare the sinking rate of Venice over the last 2,000 years and the last century to show it is sinking more quickly, which is absolutely true."

But he said the study did not take into consideration a slowing down of the city's inundation in the past decade because the city had stopped pumping water from the bedrock underneath the city.

The earth's natural underground water supplies acted as a cushion that helped slow the city's sinking, he said.

More important, Costa disputed the study's reliance on what he said were unspecified and unsourced future projections for global warming to bolster the assertion that the dam project would be insufficient.

Costa added: "I can assume he (Ammerman) knows everything about the past, but not about global warming.

"They rely on someone else's forecasts for global warming. That's not science. We have our own forecast."

The city hopes work will start soon on a $4 billion dam project, named Moses, which would involve a series of moveable dams.

The origins of the project date back to 1966, when the city risked being destroyed by a flood, and it has provoked plenty of controversy in the intervening 36 years.

Environmentalists are against it because they argue it will harm the ecological balance of the lagoon that Venice sits on.

But without the dams -- and the sinking aside -- Venice remains vulnerable to another flood and high tides that each year erode buildings and flood squares.

Ammerman believes that, if ever built, the dams would have to be closed for as much as 150 days a year, effectively turning the city into a pond for half the year.

Copyright 2000 Reuters. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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