Ruzizi River
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The Ruzizi (also sometimes spelled Rusizi) is a river, long, that flows from
Lake Kivu Lake Kivu is one of the African Great Lakes. It lies on the border between the Democratic Republic of the Congo and Rwanda, and is in the Albertine Rift, the western branch of the East African Rift. Lake Kivu empties into the Ruzizi River, which ...
to
Lake Tanganyika Lake Tanganyika () is an African Great Lake. It is the second-oldest freshwater lake in the world, the second-largest by volume, and the second-deepest, in all cases after Lake Baikal in Siberia. It is the world's longest freshwater lake. ...
in
Central Africa Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo, ...
, descending from about to about above sea level over its length. The steepest gradients occur over the first , where
hydroelectric dams Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...
have been built. Further downstream, the Ruzizi Plain, the floor of the
Western Rift Valley The Albertine Rift is the western branch of the East African Rift, covering parts of Uganda, the Democratic Republic of the Congo (DRC), Rwanda, Burundi and Tanzania. It extends from the northern end of Lake Albert to the southern end of Lake ...
, has gentle hills, and the river flows into Lake Tanganyika through a
delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...
, with one or two small channels splitting off from the main channel. The Ruzizi is a young river, formed about 10,000 years ago when
volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...
associated with continental
rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...
ing created the Virunga Mountains. The mountains blocked Lake Kivu's former outlet to the
drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, t ...
of the
Nile The Nile, , Bohairic , lg, Kiira , Nobiin language, Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered ...
and instead forced the lake overflow south down the Ruzizi and the drainage basin of the Congo.


Course

Along its upstream reaches, the river forms part of the border between
Rwanda Rwanda (; rw, u Rwanda ), officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of Central Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator ...
on the east with the
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
(DRC) on the west. Further downstream, it forms part of the border between the DRC and
Burundi Burundi (, ), officially the Republic of Burundi ( rn, Repuburika y’Uburundi ; Swahili language, Swahili: ''Jamuhuri ya Burundi''; French language, French: ''République du Burundi'' ), is a landlocked country in the Great Rift Valley at the ...
, and its lowermost reach lies entirely within Burundi. To the west, the
Fizi Fizi is a territory in the south of Sud-Kivu Province, Democratic Republic of the Congo, bordering the South Kivu territories of Uvira, Mwenga and Shabunda to the north, Lake Tanganyika or Tanzania in the east, and the provinces Katanga in the s ...
Baraka Baraka or Barakah may refer to: * Berakhah or Baraka, in Judaism, a blessing usually recited during a ceremony * Barakah or Baraka, in Islam, the beneficent force from God that flows through the physical and spiritual spheres * Baraka, full ''ḥ ...
mountains tower over the river. The Bridge of Concord, Burundi's longest bridge, crosses the river near its
mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...
. Tributaries of the Ruzizi River include the Nyamagana, Muhira, Kaburantwa, Kagunuzi, Rubyiro and Ruhwa, among others. The Ruzizi River, flowing south into Lake Tanganyika, is part of the upper watershed of the Congo River. Nineteenth-century British explorers such as
Richard Francis Burton Sir Richard Francis Burton (; 19 March 1821 – 20 October 1890) was a British explorer, writer, orientalist scholar,and soldier. He was famed for his travels and explorations in Asia, Africa, and the Americas, as well as his extraordinary kn ...
and
John Hanning Speke Captain John Hanning Speke (4 May 1827 – 15 September 1864) was an English explorer and officer in the Indian Army (1895–1947), British Indian Army who made three exploratory expeditions to Africa. He is most associated with the search ...
, uncertain of the direction of flow of the Ruzizi, thought that it might flow north out of the lake toward the
White Nile The White Nile ( ar, النيل الأبيض ') is a river in Africa, one of the two main tributaries of the Nile, the other being the Blue Nile. The name comes from the clay sediment carried in the water that changes the water to a pale color. ...
. Their research and follow-up explorations by
David Livingstone David Livingstone (; 19 March 1813 – 1 May 1873) was a Scottish physician, Congregationalist, and pioneer Christian missionary with the London Missionary Society, an explorer in Africa, and one of the most popular British heroes of t ...
and
Henry Morton Stanley Sir Henry Morton Stanley (born John Rowlands; 28 January 1841 – 10 May 1904) was a Welsh-American explorer, journalist, soldier, colonial administrator, author and politician who was famous for his exploration of Central Africa Cen ...
established that this was not the case. The Ruzizi flows into Lake Tanganyika, which overflows into the
Lukuga River The Lukuga River is a tributary of the Lualaba River in the Democratic Republic of the Congo (DRC) that drains Lake Tanganyika. It is unusual in that its flow varies not just seasonally but also due to longer term climate fluctuations. Location ...
about south of
Ujiji Ujiji is a historic town located in Kigoma-Ujiji District of Kigoma Region in Tanzania. The town is the oldest in western Tanzania. In 1900, the population was estimated at 10,000 and in 1967 about 41,000. The site is a registered National His ...
. The Lukuga flows west into the
Lualaba River The Lualaba River flows entirely within the eastern Democratic Republic of the Congo. It provides the greatest streamflow to the Congo River, while the source of the Congo is recognized as the Chambeshi. The Lualaba is long. Its headwaters are in ...
, a major tributary of the Congo.


Geology

Rifting, the slow pulling apart of a
tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...
plate, has produced the
East African Rift The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of a ...
system and its many basins and lakes. The system, on the boundary between the
African Plate The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plat ...
(Nubian Plate) and the
Somali Plate The Somali Plate is a minor tectonic plate which straddles the Equator in the Eastern Hemisphere. It is currently in the process of separating from the African Plate along the East African Rift Valley. It is approximately centered on the isl ...
, has two branches, both oriented north–south. Rifting in the western branch, called the
Albertine Rift The Albertine Rift is the western branch of the East African Rift, covering parts of Uganda, the Democratic Republic of the Congo (DRC), Rwanda, Burundi and Tanzania. It extends from the northern end of Lake Albert to the southern end of Lake Tan ...
, began between 25 and 10 million years ago. The Ruzizi River lies along the western rift, which includes, from north to south, lakes
Albert Albert may refer to: Companies * Albert (supermarket), a supermarket chain in the Czech Republic * Albert Heijn, a supermarket chain in the Netherlands * Albert Market, a street market in The Gambia * Albert Productions, a record label * Alber ...
,
George George may refer to: People * George (given name) * George (surname) * George (singer), American-Canadian singer George Nozuka, known by the mononym George * George Washington, First President of the United States * George W. Bush, 43rd Presid ...
,
Edward Edward is an English given name. It is derived from the Anglo-Saxon name ''Ēadweard'', composed of the elements '' ēad'' "wealth, fortune; prosperous" and '' weard'' "guardian, protector”. History The name Edward was very popular in Anglo-Sa ...
, Kivu, Tanganyika,
Rukwa Rukwa Region (''Mkoa wa Rukwa'' in Swahili) is one of Tanzania's 31 administrative regions with a postcode number 55000. The regional capital is the municipality of Sumbawanga. According to the 2012 national census, the region had a population ...
,
Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...
, and others.
Uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...
associated with the rifting altered the connections among the region's water bodies. About 13,000 to 9,000 years ago,
volcanic activity Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...
blocked Lake Kivu's former outlet to the watershed of the
Nile The Nile, , Bohairic , lg, Kiira , Nobiin language, Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered ...
. The volcanism produced mountains, including the Virungas, which rose between Lake Kivu and Lake Edward, to the north. Water from Lake Kivu was then forced south down the Ruzizi. This, in turn, raised the level of Lake Tanganyika, which overflowed down the Lukuga River. Variations in uplift and climate have caused the Ruzizi and Lukuga to open and close multiple times since then.


Hydroelectricity

The Ruzizi I hydroelectric dam was built at the Ruzizi River outlet from Lake Kivu in 1958. The Ruzizi II power station was added in 1989. Ruzizi I and II are operated by a tri-national company (Burundi, Rwanda and Democratic Republic of the Congo) owned by the
Economic Community of the Great Lakes Countries The Economic Community of the Great Lakes Countries (ECGLC) (in French CEPGL - ''Communauté Économique des Pays des Grand Lacs'') is a sub-regional organization with multiple purposes created by the signing of the Agreement of Gisenyi in Rwanda o ...
. The consortium is planning two more dams, Ruzizi III and Ruzizi IV. Ruzizi I has a generating capacity of about 30
megawatts The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wat ...
(MW) and Ruzizi II about 44 MW. Ruzizi III, to be built downstream of the other two, is projected to have a capacity of 145 MW when it becomes operational in about 2027. As part of the Ruzizi III project, Ruzizi I and II are to be refurbished. If eventually built, Ruzizi IV will be positioned between Ruzizi II and Ruzizi III and is projected to operate at more than 200 MW. On January 16, 2020, the African Development Bank allocated €8 million for technical assistance on the Ruzizi IV hydroelectric project. It is expected to provide 287 MW to the Democratic Republic of the Congo, Rwanda and Burundi.


Fauna and flora

Reed swamps are common along the lower
main stem In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow.. A ...
of the river and its tributaries. Near the mouth, the
riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
swamps are up to wide. The swamps' total area in Burundi has been estimated at with reeds varying in height from , depending on the degree of inundation. Residents use the reeds for
thatching Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge (''Cladium mariscus''), rushes, heather, or palm branches, layering the vegetation so as to shed water away from the inner roof. Since the bulk of ...
and other domestic purposes. Further from the river, much of the lower river valley consists of grassland, heavily grazed by cattle. A widely publicized man-eating crocodile, Gustave, roams the banks of the Ruzizi River and the northern shores of Lake Tanganyika. Gustave, estimated to be about long and to weigh about , is said to have killed and eaten many people. In the film documenting Gustave ("Capturing the Killer Croc"), the narrator states that "In the 1950s, buffalo,
elephants Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and ...
and
common warthog The common warthog (''Phacochoerus africanus'') is a wild member of the pig family (Suidae) found in grassland, savanna, and woodland in sub-Saharan Africa. In the past, it was commonly treated as a subspecies of ''P. aethiopicus'', but today t ...
s inhabited the plain; but they were progressively exterminated by man. The only survivor amongst the large mammals has been the
hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extan ...
. And they share the river, in an uneasy co-existence, with the
nile crocodile The Nile crocodile (''Crocodylus niloticus'') is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern ...
s."


See also

* Pont Ruzizi I *
Pont Ruzizi II The Pont Ruzizi II is one of bridge, bridges in Bukavu which serves as one of the borders customs between Democratic Republic of Congo in the town of Bukavu and Rwanda in the Cyimbogo region over the Ruzizi River. This bridge is located at the re ...


References


External links

{{Authority control Tributaries of the Congo River International rivers of Africa Rivers of Burundi Rivers of Rwanda Rivers of the Democratic Republic of the Congo Border rivers Burundi–Democratic Republic of the Congo border Democratic Republic of the Congo–Rwanda border Lake Kivu Tributaries of Lake Tanganyika Rusizi District Ramsar sites in Burundi