The overall water quality at the Three Gorges Reservoir remains stable and no unexpected changes have been recorded since the water storage began, officials said in Beijing Thursday.

Xu Shubi, deputy director of Chongqing Municipal Bureau of Environmental Protection, said most indicators at the Three Gorges Reservoir were up to the state's required water quality, after 20 consecutive days of monitoring.

The water quality at the Three Gorges Reservoir remained almost unchanged, compared with the monitoring data conducted during the same period last year, Xu said.

Only the indication of fecal colibacillus in the Chongqing reservoir area exceeded the state's standards, he said.

The construction of the Three Gorges Project had so far resulted in no ecological disasters at the reservoir, according to the results from five years of environmental monitoring by the central government.

Some of the environmental indicators are improving instead, according to the survey.

However, some analysts said the environmental protection at the reservoir area would face tougher challenges ahead with the slowdown of the stream after water storage.

The reservoir's dilution and self-cleaning capacities might decline, they said.

But designers of the project dismissed those worries.

"We have attached great importance to environmental protection in the reservoir area from the very beginning of the project," said Pan Jiazheng, one of the designers.

"Moreover, we have learned lessons on how to avoid disasters from the construction of the world's other major dams," Pan said.

China plans to invest some 40 billion yuan (US$4.8 billion) in curbing water pollution in the reservoir and along the upper reaches of the Yangtze River from 2001 to 2010. More than 150 new sewage treatment plants and 170 garbage disposal facilities will be built.

Environmental protection authorities in Chongqing have organized special teams to closely monitor the reservoir's water quality before and after water storage began on June 1, when the sluice gate was closed.

Authorities also closed about 1,000 enterprises discharging pollutants far exceeding the state's standards before the water storage.

During the reservoir area clean-up before filling began, 1.99 million tons of domestic garbage and 1.98 million tons of industrial garbage had been cleared. Meanwhile, 5 million square meters of sewage facilities and more than 20,000 tombs in the reservoir area had been disinfected.

"Many causes of pollution in the Yangtze River can be well controlled," said Zhang Shaozhi, director of Chongqing Municipal Bureau of Environmental Protection. "This has been proved by past experience."

The construction of the Three Gorges Project, the world's biggest hydro-electric project, began in 1993 and is expected to be completed in 2009.

(Xinhua News Agency June 12, 2003)