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June 15, 2011

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Home » Metro » Environment

Floating fern waterway threat

A FLOATING water plant carried into local rivers and creeks by recent heavy rains is clogging up waterways and threatens shipping, officials warned yesterday.

Authorities have increased the number of vessels tasked with removing azolla, an aquatic fern, said the city waterway sanitation keeper.

The amount removed from the Huangpu River and local creeks since early this month is more than three times that taken out in the same period last year, according to the Shanghai Environment Industry Co Ltd, which monitors local waterway sanitation.

Managers fear the seasonal problem will be worse in Shanghai this summer because of the weather.

Droughts in many parts of the Yangtze River were followed by floods.

This sudden change in the water environment has spurred rapid growth of free-floating azolla, said Fang Xiaofeng, an official with the waterway sanitation authority.

"We have discovered that a massive quantity of the fern has been carried down to local waters since early this month," Fang explained.

Last summer, the largest surface area on local waters covered by the fern was 800,000 square meters.

But already this summer sanitation workers have reported an area of more than 1 million square meters.

Since June 8, staff have been removing 400 tons of azolla a day.

In addition to being unsightly, in clogging up waterways, the plant - which is also known as fairy moss - can cause problems for passing ferries and other vessels.


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