Akosombo Dam

The Akosombo Dam, also known as the Volta Dam, is a hydroelectric dam on the Volta River in southeastern Ghana in the Akosombo gorge and part of the Volta River Authority. The construction of the dam flooded part of the Volta River Basin and led to the subsequent creation of Lake Volta. It covers 8,502 square kilometres (3,283 sq mi), which is 3.6% of Ghana's land area, making it the largest artificial lake by surface area in the world. With a volume of 148 cubic kilometers, Lake Volta is the world's third-largest man-made lake by volume; the largest being Lake Kariba which contains 185 cubic kilometers of water. The primary purpose of the Akosombo Dam was to provide electricity for the aluminium industry. The Akosombo Dam was called "the largest single investment in the economic development plans of Ghana". The dam is significant for providing the majority of both Togo and Benin's electricity, although the construction of the Adjarala Dam (on Togo's Mono River) hopes to reduce these countries' reliance on imported electricity. The dam's original electrical output was 912 megawatts (1,223,000 hp), which was upgraded to 1,020 megawatts (1,370,000 hp) in a retrofit project that was completed in 2006. The flooding that created the Lake Volta reservoir displaced many people and had a significant impact on the local environment, including seismic activity that led to coastal erosion; a changed hydrology caused microclimatic changes with less rain and higher temperatures. The soil surrounding the lake is less fertile than the soil under it, and heavy agricultural use has required the use of fertilizers, which in turn has led to eutrophication, which caused, among others, the explosive growth of an invasive weed, Ceratophyllum, that renders water navigation and transportation difficult, and forms a habitat for the vectors of water-borne illnesses such as bilharzia, river blindness and malaria. Resettlement of the displaced inhabitants proved complex and in some cases unsuccessful; traditional farming practices disappeared, and poverty increased.

The dam was conceived in 1915 by geologist Albert Kitson, but no plans were drawn until the 1940s. The development of the Volta River Basin was proposed in 1949, but because funds were insufficient, the American company Volta Aluminum Company (Valco) lent money to Ghana so that the dam could be constructed. President Kwame Nkrumah adopted the Volta River hydropower project and commissioned Australian architect Kenneth Scott to design a residence for him overlooking the dam. The dam is 660 m (2,170 ft) long and 114 m (374 ft) high, comprising a high rock-fill embankment dam. It has a base width of 366 m (1,201 ft) and a structural volume of 7,900,000 m3 (10,300,000 cu yd). The reservoir created by the dam, Lake Volta, has a capacity of 148 km3 (120,000,000 acreft) and a surface area of 8,502 km2 (3,283 sq mi). The lake is 400 km (250 mi) long. Maximum lake level is 84.73 m (278.0 ft) and minimum is 73.15 m (240.0 ft). On the east side of the dam are two adjacent spillways that can discharge about 34,000 m3/s (1,200,000 cu ft/s) of water. Each spillway contains six 11.5-metre (38 ft)-wide and 13.7-metre (45 ft)-tall steel floodgates. The dam's power plant contains six 170-megawatt (230,000 hp) Francis turbines. Each turbine is supplied with water via a 112–116-metre (367–381 ft) long and 7.2-metre (24 ft) diameter penstock with a maximum of 68.8 m (226 ft) of hydraulic head afforded. The final proposal outlined the building of an aluminum smelter at Tema, a dam constructed at Akosombo to power the smelter, and a network of power lines installed through southern Ghana. The aluminum smelter was expected to eventually provide the revenue necessary for establishing local bauxite mining and refining

Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).