by Peter Huck
http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10733015
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.
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