Tuesday, 30 December 2014

Engineering in China - Another Milestone Achievement in Mega Engineering

Visitors stand on top of the Danjiangkou Dam in China's Hubei province on Nov. 2. The height of the dam was raised to increase the size of the Danjiangkou reservoir, which will provide water from central regions of China to Beijing. | AFP

Doubts as giant China project’s water reaches capital

by Tom Hancock 
BEIJING – A towering dam in central China holds back a vast expanse of water destined to travel over 1,000 km north to Beijing, but critics say it will only temporarily quench the city’s thirst.

China’s capital on Saturday received its first supplies from the South-North Water Diversion Project, one of the most ambitious engineering projects in Chinese history.

After decades of planning and at least $33 billion of investment, over 1 billion cu. meters of water are projected to flow to Beijing every year through more than 1,200 km of channels and pipes, equivalent to the distance from London to Madrid.

“Beijing is now formally receiving water” from the project, the city’s government said in a text message.

Another 8.5 billion cu. meters, equivalent to 3.4 million Olympic-size swimming pools, will reach provinces along the way, planners say.

The Chinese government says the project, which will ultimately have three routes and an estimated total cost of $81 billion, will solve a chronic shortage in northern cities.

Water availability per person in Beijing is on a par with Middle Eastern countries such as Israel, threatening China’s economic growth, the key source of support for the ruling Communist Party.

“This water needs to go to the north,” said a tour guide surnamed Chen, standing atop the 110-meter-high dam at the Danjiangkou reservoir in the central province of Hubei, at an altitude 120 meters higher than Beijing to allow water flow by pure gravity.

Among the engineering feats involved are a 7.2-km-long tunnel beneath the Yellow River, China’s second-biggest waterway, described in official reports as “the most enormous river crossing project in human history.”

To carry the flow over one river in Henan province, engineers built a 12 km aqueduct, the longest in the world.

But critics say that the project’s success is jeopardized by declining rainfall in southern China, and that it will only act as a temporary stopgap for the north’s insatiable demand.

Northern China supports nearly half the country’s population and economy alongside two-thirds of its arable land, but has just a fifth of the total national water supply, according to the World Bank.

Looking over the Yellow River in 1952, communist China’s founding father, Mao Zedong, is reported to have said: “The north of China needs water and the south has plenty. It would be fine to borrow some if possible.”

At a time when a single word from Mao could launch a project, studies were swiftly begun but technical concerns and lack of capital meant the idea was shelved until a revival by former President Jiang Zemin, whose government approved it in 2002.

Its construction has since taken on added urgency with water levels per person in Beijing falling to just 120 cu. meters, less than Algeria and roughly on par with Yemen, both desert countries.

The project’s eastern route, built along the 1,400-year-old Grand Canal, began transporting water from the Yangtze to Shandong province last year but has been dogged by pollution concerns, and some fear the same fate could befall the pricier central section.

State broadcaster CCTV reported last year that the Danjiangkou reservoir had become a “cesspool” due to rampant discharge of sewage into its tributaries, with human waste and animal corpses a common sight in one of them. Officials have reportedly closed thousands of factories upstream from Danjiangkou, and this year announced that the water was good enough to drink.

But years of declining rainfall in southern China means it now regularly sees droughts of its own, and analysts say the project will exacerbate those strains.

“The basic trend in the South is that rainfall decreases each year,” said Wu Xinmu of the Water Research Institute at Wuhan University.

Flow on lower sections of the rivers that feed the Danjiangkou reservoir will decline dramatically and the project will “threaten the local supply of drinking water and influence farming irrigation and industrial production” in parts of central China, researchers at the university wrote in a report.

The central route has forced the relocation of more than 330,000 people, according to state-run media.

But the 1.05 billion cu. meters it is intended to deliver to Beijing every year will be not be enough to end the city’s thirst.

As China’s cities become richer, water consumption by citizens has rocketed, and is set to grow further. The capital’s annual water use has reached 3.6 billion cu. meters, and with supplies at only about 2.1 billion cu. meters it already faces a 1.5 billion shortfall every year.

Environmentalists say water conservation is an urgent priority, and prices, currently well below global averages at around 4 yuan ($0.65) per cu. meter, need to rise.

A “supply-side approach” exemplified by the project “does not address the underlying causes of the region’s water stress,” said Britt Crow-Miller, assistant professor of geography at Portland State University, who has studied the project.

“China’s current development model is very short-sighted,” she added. “It’s about keeping things growing at all costs . . . and deferring the consequences as far into the future as possible.”

Source - The Japan Times














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