Akosombo Dam

Akosombo Dam, rock-fill dam on the Volta River, near Akosombo, Ghana. The dam rises 364 feet (111 meters) from its bedrock, has a crest 40 feet (12 meters) wide and 2,100 feet (640 meters) long, and has a structural volume of 10,390,000 cubic yards (7,943,724 cubic meters). Akosombo Dam impounds Lake Volta, a huge reservoir with a capacity of about 120,000,000 acre-feet (148,000,000,000 cubic meters) that is used for commercial fishing, irrigation, tourism, and navigation. The dam’s large power-generating capacity (1,020 megawatts as of 2006) is diverted to Ghana’s domestic needs and for export to neighboring countries.

History

When Ghana became independent in 1957, its chief economic activity was the export of cocoa. However, Kwame Nkrumah, the country’s first president, envisioned a more industrial approach to realize projects that were proposed when Ghana was a British colony of the Gold Coast. These included making use of Ghana’s bauxite reserves, a source of the naturally occurring compound alumina, which is an essential ingredient in producing aluminum, and a power scheme in the Volta River basin to support a fully integrated aluminum industry. Nkrumah pushed for an aluminum smelter at the coastal town of Tema to process the country’s bauxite reserves. Since aluminum smelting requires a lot of power, a hydroelectric project was also planned.

The site for the project was identified about 43 miles (70 km) to the north of Tema at the Akosombo gorge on the Volta River. The construction of the dam began in 1961 as part of the Volta River Project. Hard quartzite formed the bedrock of the project area, and the material was excavated and used in the dam’s construction. The volume of the Volta, Ghana’s largest river, complicated construction, with a flood on the river in 1963 pausing work for three months.

Discover how ordinary objects work, and expand your understanding of the familiar.

SIGN UP

" height="20" alt="HEW Logo">

Thank you for signing up!"

Back to homepage

By clicking "Sign Up", you consent to the Britannica Privacy Policy and Terms of Use.

The dam was jointly financed by the government of Ghana, the World Bank, the United States, and the United Kingdom. Akosombo Dam was completed in 1965 with a primary dam structure, a secondary saddle dam structure, a power station, and two spillways erected.

The dam produced 912 megawatts of electricity after its completion, which was more than the industrial demand from aluminum smelting and other domestic needs put together. This allowed Ghana to export surplus electricity to Benin and Togo and eventually to other African countries, such as Burkina Faso and Nigeria. The project gave Ghana one of the highest rates of electricity access on the continent.

When the aluminum smelter was set up at Tema in 1966, the dam supplied power as planned, though the activities of the smelter were scaled down. Instead of supporting an integrated aluminum industry, the smelter processed imported bauxite rather than local reserves of the ore.

As demand for electricity grew in subsequent decades, the initial surplus diminished. A 2006 upgrade increased the capacity to 1,020 megawatts, and the project now generates about 85 percent of Ghana’s electricity needs.

Explore Britannica Premium!

The trusted destination for professionals, college students, and lifelong learners.

SUBSCRIBE

Human and environmental impact

The construction of the Akosombo Dam caused flooding for 250 miles (400 km) along the river, creating Lake Volta. The process flooded about 740 villages, displacing about 80,000 people. The government of Ghana established 52 resettlement townships to accommodate the displaced population, but later studies have indicated that planning was insufficient. Many resettled families found the allotted space inadequate and questioned the land valuations that determined their compensation.

Before the construction of the Akosombo Dam, the Volta River regularly overflowed its banks during seasonal floods, spreading nutrient-rich silt across the surrounding lowlands and enriching the soil for agriculture. After the construction, this cycle was disrupted, and farming communities that remained around the banks of the newly formed lake had to rely on fertilizers for agriculture. These fertilizers caused chemical runoff to the lake, which promoted algal growth, attracting vermin and insects, such as mosquitoes, that acted as vectors of disease.

Heavy rainfall in September and October 2023 led to dangerously high water levels in the Volta at Akosombo. Beginning on September 15, as the reservoir’s water levels threatened to exceed the dam’s operational height limit of about 280 feet (85 meters), the Volta River Authority released water from the Akosombo Dam and the Kpong Dam, about 13 miles (21 km) downstream, to prevent dam failure. Controlled spillage continued until the end of October. The resulting downstream flooding displaced over 31,000 people and damaged crops and urban infrastructure in North and Central Tongu districts and surrounding areas.

The social impact of the spillage lasted well after the reservoir returned to normal levels. In some affected towns, such as Mepe, displaced residents lived in temporary shelters for months after the incident because of damage to their homes. Many schools remained closed, and agriculture and trade levels dropped sharply. Though primarily attributed to sudden and heavy rainfall, some experts suggest that part of the disaster from the spillage was attributable to poor planning, with the Volta River Authority allegedly initiating spillage much later than advisable and issuing delayed evacuation orders to inhabitants. A lack of a sufficiently sized uninhabited zone just downstream of the dam to absorb floodwaters was also cited as an issue.