Thursday, February 12, 2009

The Tragedy of the Akosombo.

A very important question was raised in class today. Are large hydroelectric dams green? The response of the class captured the same difference in opinion that prevails on this issue. I will withhold my opinion for the time being and present a case study. I think it is a classic example of how, sometimes, matters of policy can go horribly wrong when engineering, economics and politics decide policies and the people, the ultimate beneficiaries, are left out of the equation.

In 1957, Ghana gained its independence. And in 1963 the Akosombo Dam (approximately 900MW) was constructed on the River Volta to boost industrialization and enhance economic progress of this newly independent country. The dam was also supposed to improve fishing, irrigated farming and tourism (!?) amongst other things. It indeed helped the aluminum industry in the region and as demands kept rising, another dam was built 1981 at Kpong, downstream to Akosombo. However, four and a half decades later, I would say, the two main contributions of the Akosombo dam may be summed up as: (a) creation of Lake Volta – the largest man-made lake in the world (covering an area of ~8500 sq. km and so large it can be seen from space!) (b) putting Ghana on the WHO problem list forever!

How? Well, this is what happened.

[1] Formation of the Lake Volta upstream (the enormity of which I’ve already tried to impress upon you) resulted in a bloom in aquatic weed and a certain kind of snail that fed on it. The snails were vectors for water-borne illnesses, mainly bilharzia (a chronic illness that can damage internal organs and, in children, impair growth and cognitive development). Prevalence rates bilharzias rose from 5% to 70-75% in some lakeside communities. In some cases, rates of almost 100% have been recorded among school children.

[2] Contrary to better upstream fishing claims, colonization of weed and snails, led to a drop in shrimp and clam population – the backbone of the rural fishing industry and the main source of protein for the local population. Downstream fishing also collapsed due to reduced flow.

[3] Crop yield also declined. The lake covered most of the fertile lands and natural flooding no longer left rich alluvial deposits that improved soil fertility in the overlying upland areas.

[4] The formation of the lake resulted in relocation of about 80,000 people, originally from 700 villages, into 52 resettlement villages. Many of the original villages comprised of indigenous ethnic groups. The relocation meant a loss of homes, primary occupation and even cultural and social belongingness.

Acute poverty (from [2]&[3]) and breakdown of social and cultural values in unfavorable resettlement conditions led to contraction of HIV and has since resulted in a very high prevalence of AIDS in the Volta basin communities.

Hydroelectric power is championed as an efficient and cheap source of power without major environmental impacts. But once in a while, debacles like Akosombo makes you wonder; after all how green is hydel? If noise from wind turbines is considered to be a nuisance and offshore wind farms face opposition for spoiling your ocean-view, this should be down on the green-scale by a few orders of magnitude! Also, when you add the millions spent on healthcare over decades, the losses in income from fishing and farming, the degradation in the standard of living of displaced populations – it is not very cheap! The Akosombo also asks another question: at what point should a country’s requirement for cheap power override other considerations?

However, this as I said is a classic example of how bad it may go. Things, in general, are not so bad on the water front!

PS: Due to silting, the flow of sediment to the Volta Estuary has been cut off by the dam, causing severe coastal erosion. The neighboring countries of Togo and Benin are also affected, whose coasts are now being eaten away at a rate of 10–15 meters per year. A project to strengthen the Togo coast has cost US$3.5 million for each kilometer protected
(ref. 2).

1. Gyau-Boakye, P. 2001. Environmental impacts of the akosombo dam and effects of climate change on the lake levels. Environment, Development and Sustainability 3(1): 17-29.


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