SOUTH-EASTERN SUDAN.
(The Sobat and tributaries, and country south of the Sobat and north of N. Lat. 5° between the Bahr El Jebel and Abyssinian frontier.)
Section 1.—Description of the Sobat and its Tributaries.
River Sobat.The Sobat rises on the Abyssinian plateau somewhere about east long. 36° and north lat. 7° 15′, though its source has probably never been accurately determined, and flows generally from east to west.
For the first 260 miles (approximately), as far west as the junction of the Pibor[85], it is known by the Abyssinians as the Baro, by the Nuers as the Kir, and by the Anuaks as the Upeno; from this point to its junction with the White Nile, at a point some 55 miles by river south of Kodok and 460 miles (approximately) from its source, it is called the Sobat.
In its descent from the plateau to Gambela, for the first 150 miles, it flows in a series of rapids through wooded, mountainous, and hilly country, in a rocky bed often not more than 40 yards wide. From Gambela to Finkio (15 miles) it increases in width to about 200 yards, but in the dry season is full of rocks, especially at the bends. Throughout the remainder of its journey to the Nile it meanders across an immense dead-flat alluvial grassy plain, varied here and there by extensive woods reaching down to the water’s edge, but often nothing is visible for miles save swamp and grass with numerous termite hills, and but an occasional tree. During this part of its course its width varies as a rule from 150 to 300 yards, though occasionally it narrows to 30 or 40 yards in the marshy region between Balamkun and the Pibor.
Banks.[86]Working up stream,[87] the banks are, as a rule, firm and dry for the first 150 miles from Sobat mouth, and numerous villages are seen built actually on them. The left bank is usually higher than the right, and both banks are higher than the country in their immediate vicinity, and thus narrow swamps running parallel to the river exist well on into the dry season. These marshes are often drained by the natives through cuts in the banks in order to capture the fish in them. Above the village of Shwai the banks are alternately marshy and firm.
Navigability.Both the Sobat and Baro, probably as far up-stream as Finkio, are navigable for steamers drawing 4½ feet of water, from the middle of May till the end of December. About the middle of the latter month the appearance of sandbanks makes navigation difficult, though it is probable a channel for small boats exists throughout the year.
Fords.Both the Sobat and Baro are fordable at fairly frequent intervals in the dry season eastwards of the Dinka country.