Volta River

Category: Inland Aquatic Biomes.

Geographic Location: Africa.

Summary: A complex system of waterways and a giant artificial lake connect a wide range of habitats in a watershed shared by six countries that sometimes have conflicting interests.

Deriving its name from the Portuguese word for meander, the Volta River is the major river system for the western African nation of Ghana, and the areas surrounding it are home to some 70 percent of the Ghanaian population. Its catchment area also draws upon regions of the countries of Mali, Burkina Faso, Côte d’Ivoire, Benin, and Togo. Because of the length of the Volta, the land habitats are varied, ranging from bush to rainforest and from wooded gorges to grassy plains. The Volta is fed by the Black Volta, the White Volta, the Red Volta, and the Oti River. Both the Red and White Volta Rivers are dry from January until the rains begin in May.

In Burkina Faso, where the Black and White Volta Rivers originate, the Black Volta merges with the Sourou River. This entire area is surrounded by extensive floodplains. Flowing mostly in a southward direction for 1,000 miles (1,609 kilometers), the Volta River ultimately merges into the Gulf of Guinea in the equatorial Atlantic Ocean. The Volta River is made up of numerous headwaters and streams that tend to be intermittent in the upper reaches, evolving into permanent bodies of water in the lower reaches.

The catchment as a whole comprises some 154,400 square miles (400,000 square kilometers). About 39 percent of the basin—including massive Lake Volta, the engineered result of major dam-building—lies within Ghana’s borders; some 46 percent lies within Burkina Faso, and smaller sections are found in Togo (6 percent), Benin (4 percent), Mali (3 percent), and Côte d’Ivoire (2 percent).

The climate of the Volta River Basin is subhumid to semiarid, an aspect of its location within the West African Savanna Zone. Because of topography and shifting climate patterns, rainfall varies greatly, with the southeastern area averaging more than three times the rainfall of the extreme northern area. Within the Volta River basin as a whole, however, some 70 percent of rain falls between July and September. The average rainfall overall in Ghana tends to be about 29 inches (237 millimeters). There is almost no rain between November and February. The year-round temperature range is 69–79 degrees F (20–26 degrees C) around the region.

Biodiversity

Great expanses of savanna border the major streams within the Volta River basin. These vary from savanna grassland in the north, to savanna woodland in the center, and finally yield to some swaths of rainforest in the southwest. Conditions within the river are similar to those within the Niger River—which arcs across the northern reaches of the Volta catchment—and it is believed that the Black Volta may have originally been a tributary of the Niger.

At least 145 species of fish live in the waters of the Volta River, including mormyrids, mochokid catfish, and characins. Most of these species are insectivores, substrate feeders, or fish predators. They have adapted to seasonal flooding by spawning and feeding upriver as the floods begin. Many native species have disappeared because of habitat degradation and damming of waters along the river. Only nine fish and a single crab species are endemic (found nowhere else) to the Volta. The river is also home to 40 species of aquatic reptiles and 25 aquatic mollusks. Mammals within this ecoregion include the marsh mongoose, African clawless otter, spot-necked otter, hippopotamus, and West African manatee, the last of which is considered vulnerable.

One of the major wetland areas within the Volta River basin is Muni-Pomadze, which lies within the Muni Lagoon watershed near the river’s mouth. It is located some 35 miles (56 kilometers) from the capital of Ghana, Accra, on the Atlantic coast. Recognized as one of the most important coastal wetlands in the world, this wetland has both local and global significance. It is a major breeding and nesting site for migratory birds, and is home to a host of waterbirds, insects, and terrestrial vertebrates. Blackchin tilapia is a key fish species of the lagoon.

People from all over the world come to Muni-Pomadze to attend the Aboakyer Festival, an ecotourist attraction. For locals, the festival is an occasion for traditional hunting trips. In earlier times, the woods were full of bushbucks, leopards, antelopes, lions, mongooses, and a variety of other animals. Many of those animals, particularly lions, have dwindled in number in response to hunting and environmental degradation.

Vegetation within the wetland includes grassland, thicket islands, and savanna trees. Studies have shown that degradation of the wetland is occurring as the result of wood being cut down indiscriminately for fuel, frequent bushfires, hunting of wildlife, and agriculture.

Human Activity

Population has been rapidly increasing in the countries of the Volta River Basin, surpassing 16 million around the year 2000, 19 million by 2012, and is projected to double by the late twenty-first century. The countries sharing the basin generally have high poverty rates and economies that remain undeveloped. There is widespread use of unsustainable agricultural methods, which result in significant environmental degradation.

Because of competing demands on the resources of the Volta River, much of the area’s environment has become vulnerable to a variety of influences. Biodiversity is decreasing, fishing and groundwater resources are being depleted, increased flooding is a major concern, and pollution—agricultural, industrial, and municipal—within the river is on the rise.

In the mid-1960s, the 912-megawatt Akosombo Dam was built on the Volta River in partnership with a foreign company, creating Lake Volta, the largest human-made lake in the world by surface area. From the dam, Lake Volta spreads northward for 250 miles (402 kilometers); its total surface area is 3,275 square miles (8,485 square kilometers). The lake is maintained chiefly for its ability to generate hydroelectric power; up to 80 percent of Ghana’s power has been derived from the lake.

Lake Volta is also a major transportation and trade source. More than half of the labor force in Ghana is employed in agriculture and fishing. Consequently, farmers use the lake to irrigate their crops, and fishers depend on its abundant resources for survival. As the land of the Volta River Basin stretches away inland from the coast, it becomes more arid, resulting in shorter growing seasons and more erratic rainfalls—making the lake’s irrigation capacity all the more valuable.

Overpumping of the river’s waters has been a major issue. In 2006, the riparian nations established the Volta Basin Authority as a means of managing the watershed. However, cooperative administration remains elusive. Relations have been particularly tense between Ghana and Burkina Faso, with Ghana demanding greater hydroelectric capabilities and Burkina Faso insisting on more water for irrigation. Both countries have constructed additional dams and power facilities, but have not been scrupulous about communicating intentions, for example, opening floodgates without notice in some cases.

Some efforts are being made to combine profit-making activities with environmental responsibility in the region. In 2009, for example, officials in Ghana began working with a Canadian timber firm on a sustainable form of artisanal logging that does not involve cutting down healthy trees. Instead, laborers use sonar to locate trees that have been submerged, and then recover them for timber use. Many such trees have been at the bottom of the Volta River since the building of Akosombo Dam in the 1960s. At that time, 100 species of trees including ebony, teak, and mahogany were submerged. Today, those recovered trees may be worth thousands, or even millions, of dollars.

Bibliography

Gao, Yongzuan and Amy Margolies. “Transboundary Water Governance in the Volta River Basin.” Center for Development Research of Bonn University. www.zef.de/fileadmin/webfiles/downloads/press/transboundary‗water‗management‗volta.pdf.

Gyasi, Edwin A. and Juha I. Uitto, eds. Environment, Biodiversity, and Agricultural Change in West Africa: Perspectives from Ghana. New York: United Nations University Press, 1997.

Ntow, William Joseph. “Pesticide Residues in Volta Lake, Ghana.” Lakes and Reservoirs: Research and Management 10, no. 4 (2005).

“Volta River Basin Ghana & Burkina Faso.” International Union for Conservation of Nature, 2012, portals.iucn.org/library/efiles/documents/2012-010.pdf. Accessed 18 Aug. 2022.

Wuven, A. M. and D. K. Attuquayefio. “The Impact of Human Activities on Biodiversity Conservation in a Coastal Wetland in Ghana.” West Journal of Applied Ecology 9 (2006).