In South Sudan, the river that owns the most territory delivers the least water. The Bahr el Ghazal, Arabic for sea of gazelles and Naam River in Nuer, is the main western tributary of the Nile. It spans 716 kilometres and embraces a watershed of 520,000 sq km, yet flows through the Sudd wetlands to Lake No where it joins the White Nile with only a fraction of its headwater volume.
The Largest Basin With the Smallest Return: 716 km and 520,000 sq km
The Bahr el Ghazal serves as a tributary to the left bank of the White Nile River, spanning a length of 716 km and embracing a watershed area of 520,000 km2. The Bahr el Ghazal is the main western tributary of the Nile, 716 km long, flowing through the Sudd wetlands to Lake No where it joins the White Nile. Including its tributaries, its basin is 851,459 sq km and reaches west to the border of the Central African Republic and northwest to the Darfur region.
The river was first mapped in 1772 by French geographer Jean-Baptiste Bourguignon d'Anville, although it was vaguely known to early Greek geographers. Its Arabic name, sea of gazelles, reflects the open savanna its tributaries traverse before vanishing into swamp. The South Sudanese region of Bahr el Ghazal takes its name from the river, not the reverse — an indication of how central this system is to identity even when its water is modest.
Hydrologically, the basin is a paradox. The Bahr al Ghazal's drainage basin is the largest of any of the Nile's subbasins, measuring 520,000 km2, but it contributes a relatively small amount of water, about 2 cubic metres per second annually, due to tremendous volumes being lost in the Sudd wetlands. Seasonally, the river's discharge ranges from nothing to 48 m³/s. The Bahr el Ghazal basin which discharges about 12 billion m³ per annum loses 11.4 billion m³ per annum of its flow to the Sudd wetland leaving only 0.6 billion m³ to flow into Lake No. Hence the average discharge of the White Nile at Malakal is shaped less by Ghazal's input than by its evaporation.
Where It Begins: Jur, Tonj and the Azande Plateau
Source definitions shift with the mapmaker. According to some sources, the river is formed by the confluence of the Jur River and Bahr al-Arab rivers. However other more recent sources say the river rises in the Sudd wetlands with no definitive source, that the Jur River joins at Lake Ambadi, and the Bahr al-Arab joins below that. The second source is listed as Jur River at Ibba, Western Equatoria at 4°22′12″N 29°15′25″E, elevation about 428 m above sea level, with mouth at White Nile at Pariang, Ruweng at 9°31′N 30°25′E, elevation 396 m.
Originating from the northern slopes of the Azande Plateau, the Jur and Tonj Rivers commence their course in southwestern Sudan, meandering northward into Lake Ambadi before assuming the nomenclature Bahr el Ghazal. The river persists in its northeasterly trajectory, merging with the Bahr el-Arab River and ultimately joining the White Nile River, contributing to the replenishment of Lake Noor. The Jur River's headwaters flow from the Congo-Nile Divide, which separates the Nile and Congo River basins, along South Sudan's border with the Democratic Republic of the Congo and the Central African Republic.
The Jur River was explored by John Petherick between 1853 and 1865. In 1897–98 the Jur River was carefully surveyed throughout its course by Lieutenant A.H. Dyé and other members of a French mission under Jean-Baptiste Marchand during the Scramble for Africa. Those surveys established Wau, now capital of Western Bahr el Ghazal state, as the key town on the Jur — still the logistical hub for any traverse of the system.
"Bahr el Ghazal teaches a hard accounting: the largest basin does not guarantee the largest flow."
— TIMELESS GENIE FEEDS DESK
Tributary Archipelago: Lol, Tonj, Bahr al-Arab and the Vanishing Channels
According to author Mamdouh Shahin, the Lol, Jur, Tonj, Bahr al-Arab, and others streams are all tributaries of the Bahr el Ghazal, but their channels disappear in the wetlands before reaching any outlet. It is fed by a number of tributaries including the Lol, Yei, Jur, Tonj and Naam rivers. The city of Wau, the capital of Western Bahr el Ghazal state, is situated on the Jur River. The Jur and Bahr el Arab merge to form Bahr el Ghazal, and after joining Bahr el Jebel at Lake No, the river is called the White Nile.
When it enters South Sudan, Bahr el-Arab meets with River Lol; and from their confluence it becomes River Kiir, which joins River Jur to form the Bahr el-Ghazal. Between the Jur and the Nile, the Tonj, the most westerly of these rivers, joins the Jur a little above its confluence with the Ghazal. The Rohl or Yalo, farther east, empties into a wide channel known as Khor Deleb, which joins the Ghazal some 9 miles above Lake No, and from the confluence the stream is known as the Deleb.
Lake No is little more than a depression into which the waters of the Ghazal system pass near the point of junction with the Bahr-el-Jebel. The lake is about 7 miles long. During the course of its flow, the Bahr al Jabal passes Lake No, where the Bahr el Ghazal connects to the Bahr al Jabal, contributing an inflow with seasonal variation. The Sudd was designated as a Ramsar Wetland of International Importance in 2006, and Bahr el Ghazal is its western feeder.
EXECUTIVE INSIGHT
For development planners, Bahr el Ghazal is a study in evaporative loss. Of 12 BCM per year generated, 11.4 BCM is lost to the Sudd, leaving 0.6 BCM at Lake No. Any investment in irrigation near Wau or in Western Bahr el Ghazal must be based on Jur and Tonj direct diversions before swamp entry, not on Bahr el Ghazal main stem flow at Lake No, where discharge can be nothing in dry months and 48 m³/s in flood. Dredging proposals from Naam River at Rubkotna junction to Lake No target vegetation-choked reaches, but risk reversing seasonal backflow from Bahr el Jebel into Ghazal during high Jebel discharges.
Field Notes: Wau to Lake No
Access begins at Wau on the Jur River, with road links to the Congo-Nile Divide and airstrip service. The tributaries come together near Wau, making it the natural base for understanding the system. From Wau, follow the Jur to Lake Ambadi, where nomenclature shifts to Bahr el Ghazal, then northeast toward the Bahr al-Arab confluence and onward to Lake No. The section between Lake No and Bentiu has been described as severely overgrown with vegetation over about 30 km, requiring shallow-draft boats and local pilot knowledge.
Historically, there has been low discharge from Bahr el Ghazal into Lake No. This low discharge is reversed through backflow when the Bahr el Jebel has high discharge. That reversal matters for navigation and for fishing communities. Travel in early dry season when channels are still defined but sudd mats are less mobile, and arrange permits through Western Bahr el Ghazal state authorities.
Essential Questions About the Bahr el Ghazal
What is the Bahr el Ghazal River?
The Bahr el Ghazal, sea of gazelles or Naam River in Nuer, is the main western tributary of the Nile, 716 km long, flowing through the Sudd wetlands to Lake No where it joins the White Nile. Its basin is the largest of Nile subbasins at 520,000 sq km.
Where does the Bahr el Ghazal originate?
Recent sources place its rise in the Sudd wetlands with no definitive source, with Jur River at Ibba in Western Equatoria at 428 m as second source. Older sources describe formation by the Jur River and Bahr al-Arab confluence, with Jur and Tonj commencing on the northern slopes of the Azande Plateau.
How large is the Bahr el Ghazal basin and how much water reaches the Nile?
The main basin is 520,000 sq km, 851,459 sq km including all tributaries to the Central African Republic and Darfur. It discharges about 12 billion cubic metres per year but loses 11.4 billion to the Sudd, leaving 0.6 billion to Lake No, with discharge from nothing to 48 cubic metres per second seasonally.
What are the main tributaries of the Bahr el Ghazal?
Lol, Jur, Tonj, Bahr al-Arab, Yei and Naam rivers. The Jur and Tonj start on the Azande Plateau into Lake Ambadi, Bahr al-Arab meets Lol to become River Kiir which joins Jur to form Bahr el Ghazal. Their channels often disappear in wetlands before any outlet. Wau sits on the Jur.
Where does the Bahr el Ghazal join the White Nile?
At Lake No, where the Bahr el Ghazal connects to the Bahr al Jabal. After joining Bahr el Jebel at Lake No, the river is called the White Nile. Lake No is a depression where Ghazal system waters pass near the junction, with backflow from Bahr el Jebel during high Jebel discharge.
Bahr el Ghazal does not arrive as a single river. It arrives as a network that loses itself to become a river — Jur, Lol, Tonj, Kiir and Arab disappearing into Sudd, then reappearing at Lake No. It is a reminder that in South Sudan, water is measured not only by what flows, but by what the wetlands allow to remain.
Comments
Post a Comment