What Are The Primary Inflows And Outflows Of Lake Tanganyika?

Lake Tanganyika holds the largest volume of freshwater in Africa. Editorial credit: Tatsiana Hendzel / Shutterstock.com

Lake Tanganyika is one of the African Great Lakes and the world's second oldest freshwater lake. The lake also ranks second in the world in terms of both depth and volume. Lake Tanganyika is also the world’s longest freshwater lake, spreading across four countries in Africa: Zambia, Burundi, Democratic Republic of the Congo (DRC), and Tanzania. The majority of the lake is located in the DRC and Tanzania. The lake reaches a maximum depth of 4,820 feet, while its average depth is about 1,870 feet. The lake holds the largest volume of freshwater in Africa, which accounts for about 16% of the world’s available freshwater, covers a total area of 12,700 square miles, and has 1,136 miles of shoreline. Lake Tanganyika has a catchment area of 89,000 square miles and only two inflow rivers: the Ruzizi River and the Malagarasi River. Additionally, the lake has one primary outflow river, the Lukunga River, which discharges into the Congo River, and eventually reaches the Atlantic Ocean.

Primary Inflows

Lake Tanganika has two primary outflows: the Ruziz River and the Malagarasi River.

Ruzizi River

The Ruzizi River is one of two rivers that drains into Lake Tanganyika. From its source at Lake Kivu to its mouth, the river descends from approximately 4,900 feet above sea level to 2,530 feet above sea level, the steepest point occurring within the first 25 miles, where hydropower dams have been constructed. Upstream, the river forms the border between the DRC and Rwanda, further downstream the river forms the border between Burundi and DRC, while the lowermost part of the river lies entirely within Burundi.

Malagarasi River

The Malagarasi River also flows into Lake Tanganyika. It is Tanzania’s second longest river and has the largest watershed among all Lake Tanganyika’s inflow rivers. One of its tributaries originates in the southeastern part of Burundi and flows through the Kigoma area in Tanzania. Additionally, part of the river, within the Malagarasi-Muyovozi Wetlands, has been designated as a Ramsar site.

Primary Outflow

Lake Tanganika has one primary outflow: the Lukuga River.

Lukuga River

The Lukuga River is the primary outflow of Lake Tanganyika. It exits the lake near Kalemie, flows westward through the district of Tanganyika, and joins the Lualaba River. The river accounts for about 18% of Lake Tanganyika's water loss, while the remainder occurs through evaporation. The Lukuga River is heavily mineralized, with high concentrations of sodium, calcium, potassium, and magnesium. The river flows from the DRC's side of Lake Tanganyika and joins the Lualaba River on the eastern side of Congo-Kinshasa, and then eventually discharges its waters into the Atlantic Ocean after covering a total distance of 200 miles. The river is home to crocodiles and hippopotamuses.

Threats to the Lake

According to scientists, Lake Tanganyika is changing rapidly and may experience a turbulent future. The lake was declared the Global Nature Fund's "Threatened Lake of the Year" in 2017, which is primarily attributed to human activities that are causing climate change. Other concerns include overfishing, deforestation, and the exploitation of hydrocarbons.


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