Along With Power, Questions Flow at Laos's New Dam

Science, 23 April 2010: Vol. 328. no. 5977, pp. 414 - 415
Friday, April 23, 2010

By Richard Stone

The start-up of one of Southeast Asia's biggest hydropower dams has
launched a new round of debate over how much damage the megaproject
might inflict on the environment.

Backers led by the World Bank and the Asian Development Bank (ADB) say
that the $1.5 billion Nam Theun 2 (NT2) dam in central Laos has
already taken its most severe toll on the environment: Filling the
reservoir in 2008 involved resettling 6200 people and inundating 450
square kilometers of the Nakai Plateau. But critics say that the
ecological harm has only just begun. "NT2 will lead to very serious
impacts" for more than 100,000 people living downstream, says a U.S.
expert on water issues in Laos who asked to remain anonymous out of
fear of offending the Lao government. "World Bank and ADB will, I
expect, regret ever getting involved in this project." Not so, says a
World Bank official. "A thorough analysis of probable downstream
impacts, as well as a credible and comprehensive mitigation and
compensation program, was critical to getting the World Bank to
support NT2," he says. Both sides agree that a major experiment in
hydrology and ecology is now under way.

The project, run by the Nam Theun 2 Power Company (NTPC), diverts
water from the Nam Theun River, a tributary of the Mekong River, into
Nakai Reservoir, from which water is released via a 27-kilometer
channel to another Mekong tributary, the Xe Bang Fai. The Lao
government will plow its $2 billion share of revenue from electricity
sales in the next 2 decades into a national fund for alleviating
poverty. Other aspects of NT2 have gotten a thumbs-up from some
experts, who stress the good it will do for the impoverished Nakai
Plateau. The resettlement plan is "state of the art," says Thayer
Scudder, an anthropologist at the California Institute of Technology
in Pasadena who, with two colleagues, has served as an NT2 expert
panel since 1997. Still, Scudder cautions, "implementation is the name
of the game, not planning."

Tensions over NT2's environmental legacy have simmered for years.
"Diverting a large amount of water from one river basin to another,
via a large reservoir with deoxygenated and eutrophic water in it,
will greatly change the hydrology and water quality of the Xe Bang
Fai," says the U.S. expert, who predicts that erosion will also be a
major problem. Mitigation measures, he insists, are insufficient.

When the dam began generating electricity and water flow changed last
month, critics pounced. In a 26 March letter to the World Bank and
ADB, the advocacy groups International Rivers and Mekong Watch
asserted that water quality on the upper Xe Bang Fai deteriorated when
river levels rose 3.6 meters. The groups claimed that the rapid rise
had washed away gardens on the river's banks and that fish had
"disappeared from the river." They also charged that NTPC has failed
to provide adequate alternative drinking water supplies. "The project
is violating people's human rights by preventing access to clean water
and by destroying critical food sources without providing
compensation," contends Ikuko Matsumoto, Lao program director for
International Rivers. The letter called on the World Bank and ADB to
suspend dam operation and strengthen downstream mitigation measures.

Such criticism is unwarranted, NT2 backers say. In an 8 April letter
to International Rivers and Mekong Watch, the World Bank and ADB
asserted that "considerable progress" has been made with the
downstream mitigation and compensation program and that "effective
erosion, water quality, fish catch, and socioeconomic monitoring
systems" are in place. The letter notes that some 500 boreholes and
pumps have been installed to provide drinking water, for example.
Thanks in part to structures such as an aeration weir, "initial
results show that water quality in the Xe Bang Fai is not
significantly different to how it was prior to the project," says NTPC
spokesperson Aiden Glendinning. "These results were shared with
[International Rivers] before they made their claims of pollution and
fish loss, for which no evidence has been found anywhere along the
river," he says.

Work on NT2 has yielded one welcome surprise: a find of 38 large-
antlered muntjacs, a rare deer, on the Nakai Plateau (Science, 4
September 2009, p. 1192). But with the electrical spigot now open, the
question is whether NT2 will improve or worsen the welfare of
communities downstream. On that count, the verdict on NT2 is not yet

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