Peter Huck: Dambusters fight giant projects

They had been warned. But Chinese authorities chose to ignore concerns the Three Gorges Dam on the mighty Yangtze River would spawn more than flood control, irrigation and hydroelectricity.

For while the 2.3km wide barrier is a graphic symbol of China's economic muscle, it also shows efforts to subjugate nature come with a steep price.

Last month, China admitted the dam, the world's largest hydropower station which opened in 2008, had generated "urgent" ecological, geological and human problems.

The huge volume of water in its reservoir, which displaced 1.3 million people, is blamed for earthquake tremors, soil erosion, polluted drinking water and habitat destruction.

Nonetheless, as a climate-change world debates how to shift energy paradigms, dams help drive China's rise as a global power.

The 12th Five-Year Plan includes multiple barriers for the epic, ongoing South-North Water Transfer Project, channelling water north, via three routes, from the Yangtze and the Brahmaputra, a vision that dwarfs California's capture of water from the Colorado River for Los Angeles.

Ironically, as China ponders its Three Gorges problems and embarks on an orgy of dam construction, America, home to New Deal behemoths such as the Hoover on the Colorado and the Columbia's Grand Coulle, is busy rescuing wild rivers.

Last month the generators were turned off on Washington's Elwha Dam, built in 1913, so the Elwha can reclaim its wild river status, allowing salmon to make their first spawning run to upstream habitats in a century, a triumph for conservationists, the salmon lobby and local Indian tribes.

The US$325 million ($400 million) cost will likely be a pittance compared with the cost of decommissioning four dams on the Klamath River, in California, by 2020, history's biggest dam-removal project.

Clearly, the mega dam mantle has switched from the US to China.

"China is building most of the dams in Africa and in many developing nations," says Lori Pottinger, editor of World Rivers Review at the US based International Rivers Network.

"The expertise they got from building the Three Gorges project made them first-class dam builders. And now they're selling that expertise in return for commodities."

The boom, she says, includes "a couple of hundred" dams in Africa and more than 150 on India's Brahmaputra watershed.

Not everyone is happy. While protest is rare in China, elsewhere opposition to big dams has gone global, powered by new media, grassroots anger and evidence that huge dams aren't always the answer.

"To many people large dams have become symbols of the destruction of the natural world and of the corruption and arrogance of over-powerful and secretive organisations, bureaucrats and Governments," Patrick McCully, executive director of International Rivers, wrote in Silenced Rivers: The Ecology and Politics of Large Dams, back in 1996.

International Rivers belongs to a network of environmental, social activist and human rights groups who join peasants and indigenous people to oppose mega dams, defined by the International Commission on Large Dams (Icold) as over 15m tall or able to hold over 3 million cu m of water.

Advocates such as Icold talk up dams, noting just 8 per cent of Africa's hydro potential is used - compared with 34 per cent worldwide, mostly in Europe, Oceania and North America - while 70 per cent of Africans lack power. Dams, say Icold, control floods, provide drinking water, and power economic growth.

But the quid pro quo for big-ticket items is often commodity sales and major downstream problems. The cascade effects of, say, an aluminium smelter on poor communities that rely on river habitats can be brutal. Opponents champion a new energy paradigm. They stress interconnectiveness between people and habitats, and ground-up, sustainable projects with local involvement.

Thus, "unconventional hydro" - generating power from canals, drains, even household plumbing - eliminates many negative effects and puts power into everyday hands.

Such radicalism has political implications. "No one will move, the dam will not be built," chanted protesters against India's Narmada Dam.

"We will drown but we will not move." Such sentiments resonate in Africa, India and Latin America where protesters believe mega dams perpetuate destructive extractive industries that benefit elites.

By 1992 Icold said the anti-dam movement had reduced "the prestige of dam engineering in the public eye, and it is starting to make work difficult for our profession".

But earlier hopes that global protests would drive the international dam industry into a fatal tailspin are premature, given China's rise as a global dam builder.

Still, the ground is shifting as the effect of dams on river ecosystems and their inhabitants is recognised. While millions are affected when their upstream lands and homes are flooded, the US Nature Conservancy says 400 million worldwide who live below dams have been adversely hit.

A 2000 World Commission on Dams report agreed dams made a "significant contribution" to development. But they also exact harsh social and ecological costs, displacing people, trashing habitats and unfairly distributing benefits.

The commission hoped for change, advocating a more inclusive method of dam planning. By and large this has not happened. Top-down projects continue apace in Africa, Asia and South America, fuelling fierce local resistance.

In India, author Arundhati Roy has championed protest against the Narmada Dam.

Grassroots dambusters oppose Brazil's Belo Monte Dam, Ethiopia's Gibe 3 Dam, Chile's HidroAysen project, Panama's Barro Blanco CDM project, India's Teestra Dam, and Colombia's Urra Dam.

Closer to home, protests, amplified by International Rivers' newsletter, target Meridian Energy's plan to block the Mokihinui River on the West Coast.

"Large hydro is an archaic practice and undeserving of the label 'renewable'," writes Forest and Bird's Debs Martin, who says potential problems on a dammed Mokihinui include unnatural flow rates, habitat damage, methane production and seismic threats.

After the 1929 7.8 Murchison quake the swollen river burst through slips to engulf Seddonville.

The methane, a greenhouse gas 25 times more potent than carbon dioxide, is significant. As the scramble for alternatives to fossil fuels intensifies, hydropower is promoted as a "clean" energy. But in 2007 scientists from Brazil's National Institute for Space Research found the world's 52,000 large dams emitted 104 million tonnes of methane - produced by rotting vegetation in reservoirs - each year, or 4 per cent of the total warming caused by humans.

Dams in India and Brazil produce one-fifth of both nations' total climate change impact, says Ivan Lima, who co-wrote Methane Emissions from Large Dams as Renewable Energy Resources. The report proposes methane be converted to energy, reducing the need for new dams.

Climate change can also alter flow patterns, especially where rivers, such as the Mekong or Yangtze, are fed by glaciers or snowmelt.

"There's no hydrological record to inform builders on how to build and operate these dams," says Pottinger. "Dams could become safety hazards with extreme flooding. Or they might be white elephants unable to produce promised power."

With worldwide scarcities of potable water, deciphering a river's hydrograph - how water flow changes over time - is vital. Yet engineers are too often fixated on minimum flows and where best to site a dam to maximise power generation.

Jeff Opperman, a senior freshwater scientist with the Nature Conservancy, stresses this isn't enough; healthy rivers need variable flows to replenish river habitat. They must also sometimes inundate flood plains, often the most productive part of a river system and crucial to farmers. "Dam design is critical." Amazingly, Opperman says, this is sometimes an afterthought.

Dams drive development which often involves deforestation, soil erosion and silt build-up in reservoirs, fatal to power generation.

Lake Mead, formed by the Hoover Dam, is silting up even as dramatic water falls caused by drought, arguably linked to climate change, expose drowned canyons.

"It's an ecological disaster along the lines of the Three Gorges," says Pottinger. "We just took longer to get there. The Colorado River doesn't even reach the sea anymore."

Silt also stalks the Three Gorges Dam. Dams don't last forever. Turbines wear out. Pipes and spillways erode. Design faults appear.

Tearing down dams is expensive. But the huge sums needed to safeguard dams to cope with climate change flow rates may accelerate this trend worldwide.

Nonetheless, as many dams are here to stay and others will be built, can beneficial changes be made?

Opperman cites the Penobscot River basin in Maine where local Indians, conservationists and government agencies reached a compromise: remove two dams, upgrade a third, and install new turbines. This allowed migratory fish to re-enter the river's higher reaches while power production increased.

It is a big-picture compromise that goes some way to respecting nature and ordinary people, while tapping into the Penobscot's awesome power.

But given the mega dam juggernaut sweeping the developing world, advocates of sustainability face a tough battle. Nature is their ally.

As China struggles with the worse drought on the Yangtze in half a century, Beijing has had to recognise its grand visions rely as much on conservation as mega dams.

Three Gorges dam

1.3 million
People displaced by construction of the dam, which started in 1994.

13
Cities submerged by the 660km-long reservoir, which reached its full height last year. A further 140 towns and 1350 villages also were lost.

26
Generators produce power from the project, a dream of revolutionary leader Mao Zedong.