The successful closure of the 15-metre opening in the diversion canal dam on the Yangtze River has again cut the natural flow of the mighty river at the famed Three Gorges.

At the damming site, Chairman of the Standing Committee of the National People's Congress Li Peng praised workers for their contribution to the 17-year multi-billion dollar project.

The project, scheduled to complete in 2009, is designed to harness the world's third-longest river, which frequently bring floods to people living in the river basin.

Li said the damming of the diversion canal is crucial to meeting the goals of the second phase, which includes filling the Three Gorges Reservoir, commencing navigation through permanent ship locks, and generating electricity by 2003.

The relocation of residents affected by the giant project is crucial and the most difficult challenge faced in the project, Li emphasized, adding that efforts should be made to ensure their economic stability and well-being.

The 35-minute damming also attracted thousands of tourists, who witnessed the event from on board ships and on the banks.

Guo Shuyan, director of the Three Gorges Project Engineering Committee under the State Council, said the resettlement of the residents from below the 135-metre water level will be accomplished by the end of this year.

Guo revealed that technical standards have been well defined for the removal of buildings, trees, garbage and solid waste, and training has been provided for workers involved. Funding has already been set aside for the achievement of these ends.

Local media said that to prevent dirty water from being duscharged into the reservoir, Chongqing has already built 19 sewage and five garbage disposal centres, accounting for 86 per cent and 54 per cent of the planned total, respectively.

Hubei has started the construction of four sewage and four garbage disposal centres that are expected to be finished before June 2003.

Meanwhile, Chinese scientists and experts are working around the clock to consider the problem of potential accumulation of sediment, or silt, in the reservoir.

Silt accumulation has always been an obstacle in the construction of dams and reservoirs, and China is a leader in this area of research, said Zhang Chaoran, chief engineer of the China Yangtze Three Gorges Project Development Co.

Experts anticipate that upon completion, the Three Gorges Reservoir could accumulate an average of 530 million tons of silt each year, which would constitute a major threat to the normal functioning of the project's hydroelectric plant.

Scientists have worked out a solution that involves discharging the silt through a series of big holes in a strategic area of the dam.

In addition, the government has allocated a combined sum of 2 billion yuan (US$241 million) for the project to protect the soil and water in the upper reaches of the Yangtze River and has also beefed up financial support for an ambitious tree-planting project along the river valley.

According to the Yangtze River Water Resources Committee, the State Council, the nation's cabinet, has developed a long-term comprehensive scheme to ensure the balanced development of the river, including the construction of a number of water reservoirs.

Two large reservoirs are planned for the turbulent Jinsha River, one of the main tributaries of the Yangtze's upper reaches. They will reduce silt accumulation by about 46 per cent upon completion, chief engineer Zhang Chaoran said.

(China Daily November 7, 2002)