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Dam debate

January 23, 2012

Whether it's for water, food, or energy security, many countries consider dams a key to their survival. Despite cutting carbon emissions, dams are increasingly seen as an ecological threat.

Protest against Brazil's Belo Monte dam construction
Protests against large dam projects are mounting internationallyImage: AP

Dams can prevent floods, they can provide relief during periods of drought, and they can produce clean energy.

Worldwide, dams have been seen as a key to a country's development - especially where demands for energy are on the rise and water is in short supply.

There are currently more than 45,000 major dam projects around the world and according to the International Commission on Large Dams in Paris about half of those projects are in China.

China as pioneer

More than any other country in the world, China sees its future in dams.

It uses dams to deal with its rising energy demands, and to provide enough useable water for the agricultural industry, which needs to feed a huge, increasingly wealthy population.

China's flagship is the Three-Gorges-Dam.

China's Three-Gorges-Dam
China's Three-Gorges-Dam displaced up to 2 million peopleImage: AP

It has been a controversial project, which was proposed to help stop the regular flooding of the Yangtze River in which thousands died.

Energy concerns were a lower priority, originally.

Now, the two issues - energy security and flood protection – are in conflict. To optimize energy production the reservoir has to be full. But to protect against flooding, it has to be empty.

It took 17 years to build what is now the world's most efficient dam, producing 18,200 Megawatts of electricity. It produces the equivalent of nine nuclear plants in hydropower annually at a saving of about 160 million tons of coal - and the associated carbon emissions - per year.

And to encourage economic development upstream, its huge sluice chambers are big enough to allow cargo and cruise ships to pass.

Environmental refugees

But the project has clearly had a negative impact on 1.3 to 2 million people, who were forcibly evicted and made to resettle elsewhere so that the dam could be built.

The dam has threatened the survival of more than 2,500 plant species and 330 fish species through the loss of their natural habitat. In addition, 22 animal species have been red-listed as endangered.

These are the facts so far, but the full extent of the damage will take years to determine.

It is not yet known whether the fields below the facility will suffer because they are no longer flooded with river sediment, which acts as a fertilizer.

And because the river's water level no longer varies, experts warn it will be unable to clean itself.

There is also a danger that the dam will silt up because sediment is collecting at the dam wall.

Add to this the issue of waste.

About 150 people upstream are throwing their garbage into the river because, it is said, they have no alternative. New factories are also dumping poisonous waste into the water system.

Sea change

The Chinese government has admitted that the ecological and economic effects of the dam were not sufficiently considered by the planners - and the Three-Gorges-Dams now stands as an example of all the problems that climate friendly energy production can create at such mega facilities.

Indigenous people protest against the construction of the Belo Monte dam in Brazil
Indigenous people protest the construction of Brazil's Belo Monte damImage: AP

It has led the United States to stop the construction of new mega-dams, with the government saying the ecological costs as too high.

China's experience has dampened the euphoria that mega-dams once inspired. This energy now attract protests worldwide.

In Brazil, a court recently ordered the construction of the Belo Monte dam to stop. It had been planned to build the third largest hydropower facility on the Xingu River, which is part of the Amazon.

Burma has likewise stopped plans for a major power plant on the Irrawaddy. The project had been supported by China, but in a recent announcement Burmese President Thein Sein said it was "against the will of the people."

Meanwhile, about 70 percent of the Chilean population opposes the HidroAysén megaproject in Patagonia. HidroAysén would send electricity via a 2,000 kilometer high-voltage direct current from Aysén to the capital, Santiago de Chile.

Long-term damage

These three countries may have taken stock from Egypt's experience - as well as that of China.

Egypt's Aswan Dam was celebrated as a feat of engineering when it was completed in 1971.

Now, 40 years later, the ground and soil below the dam is too salty for use because the fields have not flooded since the 1970s and because the local ground water has mixed with the sea.

This data supports findings of a World Commission on Dams (WCD) report in 2000, which said the price of such megaprojects was too high.

It stated that between 40 and 80 million people had been forced to leave their homes because of the construction of dams worldwide - the technology had made them environmental refugees. It also suggested the impact of mega-dams on the environment and climate had not been properly considered.

Author: Helle Jeppesen / za
Editor: Nathan Witkop