Three Gorges Probe

Water level at Three Gorges Project hits full capacity

(October 26, 2010)  The water level at the Three Gorges Dam, the world’s largest water control and hydropower project, reached its designed highest mark Tuesday.

The water level hit 175 meters at 9 a.m. Tuesday, said Cao Guangjing, chairman of the China Three Gorges Project Corporation (CTGPC), the developer of the project.

Raising water for the first time to 175 meters is “a milestone in the construction of the gigantic reservoir,” Cao said, adding it will enable the project to fulfill its functions of flood control, power generation, navigation and water diversion.

The new level does not mean complete success for the project. It does, however, allow for testing of various public concerns and doubts raised since the very beginning, such as the function of many key equipment, geological disasters, water quality, and sediment situation, Cao said.

The 185-meter-deep reservoir, built on the upper middle-reaches of the Yangtze, China’s longest river, began to store water in 2003.

It was the third attempt to raise the water level in the dam to full capacity since 2008.

In 2008, on the first attempt, the level was raised to 172.8 meters before geological hazards prevented it being raised further.

On the second attempt, in 2009, because of droughts downstream, the level could only be raised to 171.43 meters.

In September, the dam started holding more water back and discharging less. It reached full capacity after 47 days.

The water level-raising process allows experts to observe, research and validate the dam’s original design, according to Cao.

So far, monitoring shows the dam is operating smoothly.

The water level will be maintained at 175 meters for about two months for surveillance and then be allowed to drop. In the future, the water level will be kept at between 145 meters and 175 meters, depending on flood control needs.

That water-level fluctuation corresponds to 22.15 billion cubic meters of water, which will ensure water demand in the lower reaches during drought seasons.

The dam has helped in about 10 flood-control campaigns since 2004, including seven this year.

The embankment on the Jingjiang section, for instance, the most flood-prone section of the Yangtze, will now be able to withstand a once-in-a-century flood. It could previously withstand only a once-in-a-decade flood.

A higher water level expands the navigable course of the reservoir 150 kilometers and raises ship-passing efficiency four times, cutting navigation costs by at least one third compared with the time when water level remained at 156 meters, a previous water-raising target before 2008.

The project has generated about 440 billion kwh of electricity since its first started generating electricity in 2003.

Now, the power plant will be able to realize its designed annual power-generation capacity of 84.7 billion kwh.

“All Chinese should be proud of the dam,” said Cui Bangjian, a villager living close to the dam who likes to take walks along its embankment after meals.

“The whole scene is becoming more beautiful, and more ships come and go as the navigation area expands,” the 60-year-old man said.

The Three Gorges Project was launched in 1993 with a budget equivalent to 22.5 billion U.S. dollars.

It is a multi-functional water control system, consisting of a dam, a five-tier ship lock, and 26 hydropower turbo-generators.

By 2012, six more hydropower turbo-generators will be installed.

The project was constructed in three phases, and storing water at the 175-meter level was a requirement once the last phase of construction was complete.

After nearly 16 years of construction, work on all the main sections of the project was completed last month.

Some 1.24 million residents in Chongqing Municipality and Hubei Province were relocated to make way for construction of the dam.

Some Chinese and foreign critics said the dam would cause environmental problems.

Those concerns helped prompt the dam’s authorities to take extra measures, ensuring the project’s efficiency and safety.

Xinhua, October 26, 2010

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