From: Editor, ENN
Published November 4, 2013 09:01 AM

Do dams bring more harm or more good?

As China forges ahead with its goal to generate 120,000 megawatts of renewable energy by 2020, they are damming more and more rivers. According to China, this is a safe strategy that will curb pollution, control floods, and minimize climate change. Conservationists and scientists across the globe however, disagree.

 

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Environmentalists assert that China is, instead, blocking the free flow of rivers, destroying the ecology, uprooting millions of people, increasing the chances of earthquakes and ultimately "selling their country’s soul in their drive for economic growth".

In their search for renewable electric power, China's engineers have been building mega-dams at a rate unmatched in human history. Many far larger than the Hoover Dam on the Colorado River — which is 221 meters high and capable of generating more than 2,000 megawatts of power — are being constructed on China’s greatest rivers. Best known is the Three Gorges Dam, completed in 2008, which stretches a mile-and-a-half across the Yangtze and can generate ten times the hydropower of the Hoover Dam. Yet the Three Gorges is only a fraction of China’s current dam program.

The government is now engaged in a new expansion of dams in great staircases, reservoir upon reservoir — some 130 in all across China’s Southwest.

Since the 1950s the Chinese have built some  22,000 dams more than 15 meters tall, roughly half the world's current total. During the 1990s, as economic growth surged and air pollution spurred the need for clean energy; they turned increasingly to huge mega-dams. Protests from environmentalists have helped slow some of the building in recent years. But under the 12th Five Year Plan (2011-2015) the government seems to have cast aside restraint. Opposition has been suppressed and the dam builders are now free to move forward.

About 100 dams are in various stages of construction or planning on the Yangtze and its tributaries. All these rivers flow off the Tibetan Plateau, a geologically unstable region that averages 4,500 meters (14,800 feet) high. As they flow down through the soft, sedimentary rock, the rivers carve steep canyons, many deeper than the Grand Canyon. The risk of earthquakes is high. Probe International, a Canadian NGO,  warned in April 2012 that almost half of China’s new dams are in zones of high to very high seismic risk, and most of the remainder in zones of moderate hazard.

Read more at Yale environment 360

Three Gorges Dam image via Shutterstock.

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