Case Study: The Akosombo Dam, Ghana

35 min

Let's begin

In 1961, Ghana's first president, Kwame Nkrumah, launched a project to dam the Volta River where it cuts through a narrow gorge at Akosombo. The plan was bold: cheap hydroelectricity would run an aluminium smelter at the port of Tema and help turn Ghana into an industrial country. The dam was finished in 1965, and the lake behind it became the largest artificial lake in the world by surface area. Sixty years later, Ghanaians still argue about who gained most from it. What did Akosombo achieve, and what did it cost?

Facts

Feature	Fact
River and place	The Volta River at Akosombo, in the Akosombo gorge, south-eastern Ghana
Built	1961 to 1965; funded by the Ghanaian government with loans from the World Bank, the United States and the United Kingdom
Size of dam	114 m high and 660 m long; a rock-fill embankment dam
Reservoir	Lake Volta: about 400 km long, 8,502 km², or 3.6% of Ghana's land area
Power	Originally 912 MW; six turbines of 170 MW, giving 1,020 MW since an upgrade completed in 2006
Main purpose	Electricity for the Valco aluminium smelter at Tema, and for Ghana

Factors that favoured the dam

A narrow gorge at Akosombo, where the Volta cuts through a range of hills, so a short dam could hold back a huge lake.
A large river: the Black Volta, White Volta and Oti drain a large basin in Ghana and its northern neighbours.
A wide, fairly thinly settled basin upstream where a reservoir could form.
A planned market: the aluminium smelter at Tema, Ghana's growing towns, and neighbouring Togo and Benin.
Bauxite in Ghana, the ore of aluminium, which the planners hoped would one day supply the smelter.
Capital and expertise from the World Bank, the United States, the United Kingdom and the aluminium company Kaiser, and the determination of Nkrumah's government.

Definition

Smelter: a factory that extracts a metal from its ore by heating; aluminium smelting needs huge amounts of electricity. Spillway: a channel that lets surplus water pass over or around a dam safely. Resettlement: moving people from land that will be flooded or used for a project to new homes elsewhere. Eutrophication: the over-enrichment of water with nutrients, which causes water plants and weeds to grow rapidly.

Benefits

Electricity for Ghana's homes, towns and industry, and exports of power to Togo and Benin, for whom Akosombo supplied most of their electricity.
Industry: the Valco aluminium smelter at Tema, and power for other factories.
Lake transport: boats carry goods and people along Lake Volta between the south and the north of Ghana.
Fishing: a large new lake fishery.
Farming on the lake shore and irrigation downstream.
Tourism at the dam and on the lake.

But the power was not shared equally at first. Figure 5 shows how Akosombo's electricity was divided when it opened.

Problems

Resettlement: about 80,000 people, then 1% of Ghana's population, from some 700 villages were moved into 52 new resettlement villages. Many lost fertile land, homes, family graves and their way of life, and some new villages later lost much of their population.
Loss of farmland: the fertile valley soils now lie under the lake; the land around the shore is poorer.
Weeds and disease: nutrients and slow water let water weeds spread; they shelter the snails, flies and mosquitoes that carry bilharzia, river blindness and malaria, and these diseases increased near the lake.
Coastal erosion: with less sediment reaching the sea, the coast near Keta has been badly eroded.
Unequal benefits: Ghana paid more than half of the cost but at first received only 20% of the power.
Dependence on rain: in dry years, such as early 2007, low lake levels cut power; in very wet years, water must be spilled, and the spillage of September 2023 flooded communities downstream.

Comparing the two dams

Feature	Aswan High Dam (Egypt)	Akosombo Dam (Ghana)
River	Nile	Volta
Built	1960–1970	1961–1965
Main aim	Flood control and irrigation, then power	Power for an aluminium smelter
Capacity	2,100 MW	1,020 MW (912 MW at first)
Reservoir	Lake Nasser, 5,250 km²	Lake Volta, 8,502 km²
People moved	100,000 to 120,000	About 80,000
Key problems	Loss of silt, delta erosion, salinity, evaporation	Resettlement, weeds and disease, coastal erosion at Keta

Worked example

Worked example 1: the share of power. When Akosombo produced 912 MW, 80% went to the Valco smelter. How many megawatts did the smelter take, and how many were left for the rest of Ghana?

Smelter: 80% × 912 = 0.8 × 912 = 729.6 MW.
Rest of Ghana: 912 − 729.6 = 182.4 MW.
Conclusion: one factory used four times as much power as the rest of the country together.

Worked example

Worked example 2: comparing the lakes. Lake Volta covers 8,502 km² and Lake Nasser 5,250 km². How many times larger is Lake Volta? Rwanda's area is about 26,338 km²; roughly what fraction of it would Lake Volta cover?

8,502 ÷ 5,250 = 1.62, so Lake Volta is about 1.6 times larger.
8,502 ÷ 26,338 = 0.32, so Lake Volta would cover almost a third of Rwanda.

Warning

The two dams had different main aims. Aswan was built mainly to control the Nile flood and store water for irrigation; Akosombo was built mainly to power an aluminium smelter. Do not give the same list of purposes for both.

Tip

Use the comparison table to answer "compare" questions: write one sentence per row, with a linking word such as "whereas": "Aswan was built mainly for irrigation, whereas Akosombo was built mainly for industry."

MegaProject Institute: the history of the Akosombo Dam, and the question of whether it was an investment in Ghana or an exploitation of it. Note the evidence given on each side.

✦

Practice

Define smelter and resettlement.
Name the river, the lake and the main industry linked with the Akosombo Dam.
Give four factors that favoured building a dam at Akosombo.
Describe four benefits of the Akosombo Dam.
Explain why diseases such as bilharzia increased near Lake Volta.
Akosombo now has six turbines of 170 MW. Calculate its total capacity and the increase over the original 912 MW.
Give three differences between the Aswan High Dam and the Akosombo Dam.
"The Akosombo Dam benefited foreign companies more than the people of Ghana." Discuss.

Show answersHide answers

Smelter: a factory that extracts a metal from its ore by heating. Resettlement: moving people from land to be flooded or used to new homes elsewhere.
The Volta River; Lake Volta; aluminium smelting (Valco, at Tema).
Any four: a narrow gorge; a large river; a wide, thinly settled basin for the lake; a planned market (Valco, towns, Togo and Benin); bauxite in Ghana; foreign capital and expertise; government determination.
Any four: electricity for Ghana; power exports to Togo and Benin; industry (Valco); lake transport; fishing; shore farming and irrigation; tourism.
Nutrients from farms, sewage and cattle, with slow-moving water, let weeds spread; the weeds shelter snails, black-flies and mosquitoes that carry bilharzia, river blindness and malaria, and people living near the lake are exposed to them.
6 × 170 = 1,020 MW; increase = 1,020 − 912 = 108 MW.
Any three: river (Nile against Volta); main aim (irrigation and flood control against power for industry); capacity (2,100 MW against 1,020 MW); lake area (5,250 km² against 8,502 km²); people moved (100,000 to 120,000 against about 80,000); main problems.
For: Valco took 80% of the power at first while Ghana paid over half the cost; 80,000 people lost their land. Against: Ghana gained electricity, power exports, lake transport, fishing and industry, and its share of the power grew. A judgement should weigh both and reach a conclusion.

1Facts

2Factors that favoured the dam

3Benefits

4Problems

5Comparing the two dams

Facts

Factors that favoured the dam

Benefits

Problems

Comparing the two dams