Dam Project Tied to Flooding Woes

The very project designed to offset China’s catastrophic summer flooding, the colossal Three Gorges Dam now under construction, may actually have contributed to the damage wrought by this season’s floods, critics of China’s most ambitious public works project said Saturday.

By lulling residents and officials along the Yangtze River into a false sense of security, the Chinese government’s “extravagant claims” about the dam’s future flood-control capability may have caused local authorities to neglect maintenance of dikes and other traditional flood-prevention measures along the waterway, said Phil Williams, president of the International Rivers Network, a Berkeley-based group opposed to the dam.

“People think, ‘What’s the point of investing and upgrading the present embankment system if the Three Gorges Dam is going to take care of the problem?’ ” Williams said.

Many of those dikes have been breached in this year’s floods, the worst since 1954. Already, the inundating waters have killed more than 1,200 people, displaced millions of others and caused nearly $5 billion in damage across central and eastern China, home of the Yangtze, the world’s third-longest river. Residents are bracing for the worst as rains continue and typhoon season descends.

Beijing has used the opportunity to trumpet the flood-prevention benefits that it says will follow the Three Gorges Dam’s completion in 2009.

The $24-billion dam in Sichuan province “represents the key in controlling floods in the middle and lower reaches of the river,” the official New China News Agency said Thursday.

Until now, China has relied on a massive network of dikes, overflow basins and diversion channels to minimize flooding. Chinese experts acknowledge defects in the dikes--more than 1,000 danger spots were identified along a 140-mile stretch in Hubei province alone--but ascribe the weaknesses to the levees’ heavy saturation this summer rather than willful neglect.

But the dam project itself has been affected by the unusually severe flooding. Work on the 600-foot-tall plug virtually halted during recent storms. The dam’s locks had to be closed after water gushed through at 47,300 cubic meters per second. Hundreds of vessels were stranded.

And in an unusual degree of openness about the project, over which Beijing normally brooks no criticism or debate, the state-run China Daily newspaper recently reported that rising water levels would imperil the cofferdam, or temporary dam, erected at the site while the main dam is being built.

But the central regime adheres to the argument that the Three Gorges Dam, a dream of China’s leaders for decades, will be an effective flood-control tool in addition to generating 18,000 megawatts of electricity.

Several experts are not so sure.

For floods like those now plaguing China, the dam would have only minimal benefit, critics contend, citing the heavy rains that have hit the lower reaches of the Yangtze, out of range of the dam’s protection farther up the waterway.

“The heaviest rainfall has been in the Hubei, Hunan, Jiangsu, Anhui, Jiangxi [provinces], rather than it being just a matter of a lot of rain in Sichuan,” where the dam is located, noted a Western environmentalist based in Beijing. Also, much of the flooding has come not from the Yangtze proper but from its many tributaries.

Equally alarming to opponents is the prospect of a full reservoir behind the dam, kept at high levels to generate maximum electricity rather than leave room to catch flood water.

Contrary to the government’s assertions, “it’s a hydroelectric dam, not a flood-control dam,” Williams said.

Critics also contend that the chances of flooding upriver from the dam will increase because of heavy sediment buildup in the reservoir.

The dam’s engineers say they have taken into account siltation problems and have promised to dredge the reservoir and nearby lakes to maintain high water capacity.