SOBAT RIVER

major tributary of the Nile, joining the Bahr al-Jabal (Mountain Nile) above Malakal, The Sudan, to form the White Nile. The Sobat is formed by the confluence of its two main headstreamsthe Baro and Piboron the Ethiopian border, southeast of Nasir, The Sudan. Other Ethiopian headstreams include the Jokau, Gilo, and Akobo. From the BaroPibor confluence, the river flows about 220 mi (354 km) west-northwest in a series of meanders to its mouth on the Bahr al-Jabal, receiving two streams, the Khawr Nyanding and Khawr Ful Lus, from the south. Approaching the Nile, the Sobat deepens to 1830 ft (5 1/29 m) and narrows to 400 ft. Its enormous discharge when in flood (NovemberDecember) carries a whitish sediment that gives the White Nile its name. The Sobat and Baro rivers are navigable by steamer (JuneDecember) upstream to Gambela, Eth., and the SobatPibor waterway carries small craft during the same period to Pibor Post, about 130 mi up the Pibor from its junction with the Baro. A ferry crosses the Sobat below the mouth of Khawr Ful Lus. During the dry season, the fall in river level uncovers land used for grazing, thus providing pasturage for the cattle-owning peoples of the region.