1st Ld-Writethru-China Focus: No evidence that dam causes drought, experts say

1st Ld-Writethru-China Focus: No evidence that dam causesdrought, experts say

WUHAN, May 25 (Xinhua) -- Chinese specialists said Wednesday thatthere is no evidence to support the hypothesis that the Three GorgesDam, the world's largest water conservation project, is to blame forthe severe drought currently plaguing central China.

"According to data we currently have available, we have found noevidence that the drought was caused by the dam," said Liu Min, ameteorological specialist with the Hubei Provincial Weather Bureau.

According to data collected before and after the dam was built,Liu said the dam has had "very little" impact on regionaltemperature, humidity, wind velocity and other climate conditions.

"We believe the ongoing drought is more a periodical phenomenonthan a result of improper water conservation," Liu said.

He said the "La Nina" weather phenomenon, which occurred lastyear, disrupted normal atmospheric circulation and prevented warm,humid air currents from reaching the Yangtze River's middle andlower regions. "This caused a lack of rain in these regions sinceNovember," he said.

As a result, the worst drought to hit the region in 50 years hasaffected 9.89 million people in four of China's central provinces,including Hunan, Hubei, Jiangxi and Anhui.

Some Internet users still believe the dam is at fault for thedevastating dry spell.

"The dam has blocked water from flowing downstream, thatcertainly can cause climate changes," said a Beijinger using thescreenname "Bull village head."

Extreme weather conditions in recent years, including last year'sprolonged drought in southwest China and torrential rainfall in thecentral provinces, have occasionally retriggered public uproar overthe dam.

Zheng Shouren, an academic with the Chinese Academy ofEngineering and one of the dam's chief designers, dismissed theaccusations as being groundless and unfair.

"Had the dam not been built, the drought would have been evenworse in the middle and lower reaches of the Yangtze," Zheng said.

The dam, he said, was designed to store water toward the end ofthe Yangtze's flood season and supply water to the middle and lowerreaches in the dry season.

"During this year's January-May dry season, water supplies fromthe dam's reservoir increased the Yangtze's downstream flow by 2,000cubic meters," Zheng said.

This year, the dam's reservoir has supplied a total of 1.7million cubic meters of water to the downstream provinces of Hubei,Hunan, Jiangxi and Anhui, he said.

The current drought has led authorities to discharge even morewater from the dam. Water discharges were increased to 10,000 cubicmeters per second from May 20 this year, increasing the water flowby 3,000 cubic meters per second.

Hydrological data from Tuesday indicated that water levels in twomajor downstream hydrological stations located in the Dongting andPoyang lakes had risen by 1.56 and 1.16 meters, respectively.

Even greater discharges will be put into effect starting fromWednesday this week, according to the China Three GorgesCorporation, the company in charge of operating the dam.

Water discharges will increase to 11,000 or 12,000 cubic metersper second until the flood season begins on June 10, according toZhao Yunfa, a water conservancy engineer from the China Three GorgesCorporation. Zhao said the dam reservoir is expected to be closed upduring the flood season in order to store more water for possiblefuture droughts.

Pan Kejian, an official from the town of Bianhe, which is locatedin the middle reaches of the Yangtze, said the dam's role infighting the drought has been "significant."

"Water levels rose by at least 1 meter after the dam's reservoiraccelerated its discharges. If it rises another meter, we won't haveto rely on pumps for irrigation," Pan said.

When a massive flood hit the town in 1998, the dam was stillincomplete, and the town suffered as a result.

"We had another major flood last summer, but it was far lessdevastating, as the dam blocked some of the water," Pan said.

Cao Guangjing, chairman of the China Three Gorges Corporation,said the dam's role in drought prevention should not be denied, buthis company is also open to criticism and constructive suggestions.

"Since the dam began storing water, we have taken measures tominimize any potential impact on the local environment", he said.

Cao said his company has carried out joint experiments with theChinese Academy of Sciences to monitor water quality and contain thespread of algae that has plagued some of the Yangtze's tributaries.

The algae is another problem for which many people believe theDam is to blame, he said.

"We've been trying to remove the algae with specialized equipmentand chemicals. We've also raised algae-eating fish to try and solvethe problem in a more environmentally friendly way," he said.

Since some fish are known to spawn in great numbers duringfloods, Cao said his company is planning to create "artificial floodcrests" at the end of this month by increasing water discharges inorder to increase the number of fish in the region.

The Three Gorges Dam project was launched in 1993 with a budgetof 180 billion yuan (22.5 billion U.S. dollars).

Located on the middle reaches of the Yangtze River in HubeiProvince, the total project consists of a 185-meter-high dam, whichwas completed in early 2006, a five-tier ship lock, a reservoir and26 hydropower generators.

The project generates electricity, controls flooding by storingexcess water and helps to regulate the river's shipping capacity.