Bahr-El-Ghazal, the chief western affluent of the river Nile, N.E. Africa, which it joins in 9° 30′ N., 30° 25′ E. The Bahr-el-Ghazal (Gazelle river) is a deep stream formed by the junction of many rivers, of which the Jur (see below) is the most important. The basin of the Ghazal is a large one, extending north-west to Darfur, and south-west to the Congo watershed. The main northern feeder of the Ghazal is a large river, whose headwaters are in the country west of 24° E. where the Nile, Congo and Shari watersheds meet. Reinforced by intermittent streams from the hills of Darfur and by considerable rivers flowing north from Dar Fertit, this river after reaching as far north as about 10° 30′ pursues a general south-easterly direction until it joins the Ghazal 87 m. above the Deleb confluence (see below). This main northern feeder passes through the country of the Homr Arabs and Bahr-el-Homr may be adopted as its name. On many maps it is marked as the Bahr-el-Arab, a designation also used as an alternative name for the Lol, another tributary of the Ghazal, which eventually unites with the Bahr-el-Homr. The Bahr-el-Homr in its lower reaches was in 1906 completely blocked by sudd (q.v.) and then brought no water into the Bahr-el-Ghazal. The Sudan government, however, sent engineering parties to remove the sudd blocks and open out a continuous waterway.
Chief affluents. This Bahr-el-Homr is the only affluent of importance which has tributaries coming from north of the main stream; the rest of the very numerous affluents have their rise in the hilly country which stretches from Albert Nyanza in a general north-west direction as far as 23° E., and forms the watershed between the Nile basin and that of the Congo. The most westerly is the Lol or Bahr-el-Arab. It rises, as the Boro or Telgona, in Dar Fertit, and receives from the south and south-west the Raga, Sopo, Chel and Bongo. Dem Zobeir, formerly the chief station of Zobeir Rahama (q.v.), is near the Biri tributary of the Chel, in 7° 40′ N., 26° 10′ E. The Lol maintains a fairly straight course east to about 28° E., when it turns north-east, and in about 28&FRAC12;° E., 9&FRAC12;° N., joins the Bahr-el-Homr. The chief of the southern affluents, and that tributary of the Ghazal which contributes the largest volume of water, is the Jur, known in its upper course as the Sue, Swe or Souch. The Sue rises north of 4° N. in about 29° E., within three or four days' journey of the navigable waters of the Mbomu, a northern sub-tributary of the Congo. After flowing north for several hundred miles the Sue, now the Jur, is joined on the left bank, in about 7° 30′ N., 28° E., by the Wau, a considerable river whose headwaters are west of those of the Jur. The united stream now turns east and joins the Ghazal through a lake-like expansion (see below). The town of Wau (7° 42′ N., 28° 3′ E.), on the Jur, is the capital of the Bahr-el-Ghazal province of the Anglo-Egyptian Sudan. Meshra-er-Rek, the chief station and trading centre of the first European visitors to the country, is on a backwater south of this lake.
Between the Jur and the Nile, and following a course generally parallel with these rivers, several streams run north from the Congo-Nile watershed and join the Bahr-el-Ghazal. 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 m. 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 m. long from west to east, and the Bahr-el-Jebel, after passing through its eastern corner, changes its name to Bahr-el-Abiad or White Nile.
In their upper courses all the southern affluents of the Ghazal flow across a plateau of ferruginous laterite, their valleys having steep banks. North of 7° 20′ N. (where rapids interrupt the currents) the valleys open out and the rivers wind in tortuous channels often choked by sandbanks. This alluvial region, flooded in the rainy season, gives place about 9° N. to a sea of swamps, forming in fact part of the huge swamp region of the Nile (q.v.). Through these swamps it is almost impossible to trace the course of the various rivers. The Bahr-el-Ghazal itself is described as a drainage channel rather than a true river. From the confluence of the Lol with the Jur, above which point none of the rivers is called Bahr-el-Ghazal, to the junction with the Nile at Lake No, is a distance of about 200 m. Just above the Lol confluence the Jur broadens out and forms a lake (Ambadi) 10 m. long and over a mile broad at low water and very much larger in flood time. This lake is the home of many sudd plants of the "swimming" variety - papyrus and ambach are absent. The Balaeniceps rex, elsewhere rare, is found here in large numbers. At first the Ghazal flows north with lagoon-like expansions having great breadth and little depth - nowhere more than 13 ft.
Turning north-east the channel becomes narrower and deeper, and is characterized by occasional reaches of papyrus. Finally, the Ghazal turns east and again becomes broader until Lake No is reached. As a rule the banks in this section are marked by anthills and scrub. The anthills in one valley are so close together "that they somewhat resemble a gigantic graveyard." (Sir William Garstin). The rise of the Ghazal river in flood time is barely 3 ft., a depth sufficient, however, to place an enormous area of country under water.