Water pollution is threatening China's oldest hydropower station -- built nearly a century ago -- and has forced it to halt operation several times.

The Shilongba Power Plant, located in the western suburbs of Kunming, in southwest China's Yunnan Province, was built in 1908 using German technology and equipment, said deputy director Tian Jinghua.

It draws freshwater from Dianchi Lake to generate power, Tian said.

But it has had to suspend operation several times in recent years because of water pollution, he said. Chemical plants on the upper reaches of the Tanglangchuan River have been discharging acidic effluents into the lake.

In November 2003, acidic water "attacked" the power plant, triggering direct economic losses of up to 19 million yuan (US$2.4 million), he said.

The latest incident occurred on Oct. 15 and 16 this year. Highly acidic water forced the plant to stop generating power for 15 hours, he said.

A probe by local environment authorities found that two of the three chemical plants on the upper reaches of the Tanglangchuan River were covertly discharging highly toxic waste water.

Two guilty plants were ordered to suspend operations and improve their production processes and were fined 50,000 and 60,000 yuan, said Li Li, director of the Pollution Control Department of the Kunming Environmental Bureau.

The three polluters each agreed to pay 20,000 yuan to the power plant to partially compensate its economic losses.

"But imposing paltry fines is not likely to deter chemical plants," said Li.

She pointed out that a Kunming chemical plant would have to spend 760,000 yuan over a six-month period to dispose of waste water correctly but can only be fined 100,000 yuan if it violates waste water discharge regulations.

Environmentalists have called for tougher penalties for polluters and for actions to raise awareness of environmental protection among the public.

Water pollution is a very serious problem in China. Nearly 70 percent of China's rivers and lakes are polluted to various degrees, government statistics show.

China discharged 52.4 billion tons of waste water in 2005, up 26 percent on 2000. Only 52 percent of the waste water was treated before being discharged.

(Xinhua News Agency October 30, 2006)