From: Berhane Habtemariam (Berhane.Habtemariam@gmx.de)
Date: Mon May 17 2010 - 08:33:27 EDT
Dams in Africa - Tap that water
Controversy surrounds the argument for dam-building in Africa
May 17th 2010 | NAIROBI | From The Economist print edition
AFRICA is the "underdammed" continent. It is the least irrigated and
electrified, yet it uses only 3% of its renewable water, against 52% in
South Asia. So there is plenty of scope for an African dam-building boom.
Ghana long ago dammed the River Volta, Egypt the Nile, Zambia, Zimbabwe and
Mozambique the Zambezi. But there are new projects aplenty.
Sudan's president, Omar al-Bashir, for instance, is so proud of the new
Merowe dam in the north of his country that he made it a selling-point in
his recent election campaign. Costing $1.8 billion, it will produce 1,250
megawatts and create a lake 174km (108 miles) long, above the Nile's fourth
cataract. If all goes well, it may even fulfil an old dream to irrigate
swathes of farmland in northern Sudan, while sending electricity to run the
thirsty air-conditioners of Khartoum. And all without dirtying the
atmosphere, once the dams have been built.
China is building most of Africa's new dams out of its own pocket, with all
sorts of hoped-for spin-offs. International Rivers, a lobby that tries to
save rivers from dams it says are destructive, admits that the Chinese are
much greener these days. China Eximbank cancelled a loan for a dam in Gabon
on environmental grounds. Even so, political instability, graft and
incompetence have meant that many African dams, once built, have failed to
produce what was promised. The Inga I and II dams on the Congo river have
generated a fraction of the power they were meant to. The technology is
demanding. Seasonal rains produce muddy rivers, with higher sedimentation
than northern countries' dams filled with melted snow. That means a shorter
lifespan and heavier maintenance. Angola has spent $400m overhauling its
dams and transmission lines.
The standards set in 2000 by the World Commission on Dams, an independent
body which brought together an array of experts from all sides of the
argument and which recognises dams' local costs as well as national
benefits, are often ignored in Africa. Projects are rushed. Huge contracts
are open to corruption. Engineering can be shoddy, leading to cost overruns.
The hardest bit is hydrology. Rainfall estimates are often wrong. Some
countries must rent costly diesel generators to boost hydropower in years of
drought. Climate change makes hydrology trickier still. Reservoir water
sometimes falls too low to turn the turbines. Schemes to export power need
to speed regional integration. Ethiopia and Egypt are again rowing over how
to share the Nile waters.
The latest controversy surrounds Ethiopia's colossal Gibe III dam. It is set
to cost $2 billion and produce 1,800 megawatts, the same amount as South
Africa's Koeberg nuclear reactor. Ethiopia says it wants to dam itself into
becoming an industrial country that exports electricity, rebranding itself
"the water tower of Africa", a title that should perhaps be shared with
Congo and Guinea. Survival International, which lobbies for tribal people's
rights, says the livelihood and culture of 200,000 people in the Omo river
basin could be ruined by Gibe III. The Ethiopian government, it argues, has
behaved "criminally" in pushing through the project.
Salini Construttori, an Italian company that is building Gibe III, brushes
off such charges. The campaigners, it says, have miscalculated the volume of
water that the dam would retain. It says the water level of Lake Turkana,
across the border in Kenya, would drop by 50cm, not the five metres or more
that some claim. A measured release of water from the dam, say the builders,
should let local people grow crops all the year round for the first time.
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