The Pibor River (also called the River Pibor) is a

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

in eastern

South Sudan South Sudan (), officially the Republic of South Sudan, is a landlocked country in East Africa. It is bordered on the north by Sudan; on the east by Ethiopia; on the south by the Democratic Republic of the Congo, Uganda and Kenya; and on the ...

, which defines part of South Sudan's border with

Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...

. From its source near Pibor Post it flows north for about , joining the

Baro River The Baro River () or Baro/Openo Wenz, known to the Anuak as Openo River, is a river in southwestern Ethiopia, which defines part of Ethiopian border with South Sudan. From its source in the Ethiopian Highlands it flows west for to join the Pi ...

to form the

Sobat River The Sobat River is a river of the Greater Upper Nile region in northeastern South Sudan, Africa. It is the most southerly of the great eastern tributaries of the White Nile, before the confluence with the Blue Nile. Geography The Sobat River is ...

, which is a tributary of the

White Nile The White Nile ( ') is a river in Africa, the minor of the two main tributaries of the Nile, the larger being the Blue Nile. The name "White" comes from the clay sediment carried in the water that changes the water to a pale color. In the stri ...

. The Pibor and its tributaries drain a

watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...

in size. The river's mean annual discharge at its mouth is .

Course

The Pibor River is formed by various streams that come together at Pibor Post, a colonial era outpost built in 1912 and originally called Fort Bruce. The Pibor flows north, receiving the

Akobo River The Akobo River is a river on the border between South Sudan and Ethiopia. From its source in the Ethiopian Highlands near Mizan Teferi it flows west for to join the Pibor River. The Pibor flows into the Sobat River, which in turn empties into t ...

near Akobo. Continuing north the Pibor receives the

Gilo River The Gilo River is a river in the Gambela Region of southwestern Ethiopia. A variety of names also knows it: the Gimira of Dizu call it the "Mene", while the Gemira of Chako call it "Owis", and Amhara and Oromo settlers in the early 20th century ...

and Bela Rivers on the right, then joins the Baro River, forming the Sobat River.

Natural history

The Pibor, Baro, Gilo, and Akobo rivers all drain the

Ethiopian Highlands The Ethiopian Highlands (also called the Abyssinian Highlands) is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , whil ...

. The Baro River is by far the largest, contributing 83% of the total water flowing into the Sobat River. During the rainy season, between June and October, the Baro River alone contributes about 10% of the Nile's water at

Aswan Aswan (, also ; ) is a city in Southern Egypt, and is the capital of the Aswan Governorate. Aswan is a busy market and tourist centre located just north of the Aswan Dam on the east bank of the Nile at the first cataract. The modern city ha ...

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

. In contrast, these rivers have very low flow during the dry season.

History

The boundary between

Sudan Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...

and

was defined for the region near the Pibor River in 1899 by Major H.H. Austin and Major Charles W. Gwynn of the British

Royal Engineers The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is the engineering arm of the British Army. It provides military engineering and other technical support to the British Armed Forces ...

. They had no knowledge of the land, its inhabitants, or their languages, and were short on supplies. Rather than defining a line based on ethnic groups and traditional territories, essentially along the escarpment that separates the Ethiopian Highlands and the plains of the Sudanian Savanna, they simply proposed a line drawn down the middle of the Akobo River and parts of the Pibor and Baro rivers. This boundary was consummated in the Anglo-Ethiopian Treaty of 1902, resulting in an area in Ethiopian

Gambela Region The Gambela Region, also spelled Gambella, and officially the Gambela Peoples' Region (), is a regional state in western Ethiopia. Previously known as Region 12, its capital and largest city is Gambela. It is bordered by the Oromia Region to t ...

called the Baro Salient. This area is more closely connected to South Sudan than Ethiopia, both in terms of natural features and people. The Baro Salient was used as a sanctuary by Sudanese insurgents during the country's long civil wars. It was difficult for Sudan to exert authority over a region that is part of Ethiopia, and Ethiopia was reluctant to police this remote region and become involved in the politics of Sudan's internal conflicts.; online a
Internet Archive
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Course

Natural history

History

See also

References

Further reading