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With hyacinth defeated, new weeds choke Malawi

Malawi was not picturesque enough for the anonymous European settler suspected of importing water hyacinth a century ago. Now the legacy of that decision is all too clear as power cuts ravage the economy.

As mats of weed flow down the Shire River, Malawi's electricity stops, crippling industry and costing the country hundreds of thousands of US dollars a day.

Stretched in bunches more than 150km upstream from the Nkula hydroelectric station was one such culprit, floating vegetation never meant for Africa. It is not hyacinth, but a highly invasive plant spawned by the battle against the hyacinth.

"The vegetation is getting worse. It's blocked the whole barrage," said Wales Kalombola, a technician from the Electricity Supply Corporation.

He stood on a dam in Liwonde, known locally as a barrage, which regulates the river for the Nkula plant. But the weeds block the flow. Every day a crane hauls out tonnes of the gunk, and four trucks shuttle it to a site for burning. A second crane is due this month, said Kalombola, as are a further six trucks.

The authorities are considering buying a floating bulldozer and harvester from Aquarius Systems, a US firm that battles the weeds.

"They're struggling. It's coming down river faster than they can remove it," said Jane Dauffenbach, the firm's president.

Disruptions of hydroelectric power, which account for most of Malawi's 355MW, cost US$335 million a year, one-third of GDP, says the energy ministry.

Soil erosion and silt clog the rivers, as does hyacinth -- a bitter twist because for a time the evil weed seemed vanquished.

The floating mass that can double in size in a fortnight proliferated across the Shire until the mid-1990s. Blocking sunlight and sucking oxygen and nitrogen from the water, the plant increased acidity and damaged algae and plankton.

Unchecked it would have been an ecological disaster for Lake Malawi, the third biggest in Africa. Fishing villages with no alternative source of income faced ruin.

"In some areas 60 percent of the beach was no longer accessible," said Alexander Bulirani, deputy director of fisheries.

"And crocodiles hide in the hyacinth, so it wasn't safe for women to collect water," Bulirani said.

The weed came from Brazil and so, with help from Britain's department for international development, did its nemesis: Neochetina aerchornae and Neochetina bruchi, two beetles that eat only hyacinth. Some 500,000 bugs were released.

The hyacinth stood no chance, but Malawi has found a malign side to the weevils -- feeding on the decaying hyacinth leaves and branches has come a new breed of hippo grass and papyrus, more aggressive than traditional vegetation, said Patrick Phiri, a district fisheries officer in Mangochi.

"Just as we were winning the battle against hyacinth we realized this problem of secondary growth," he said.
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