The hydrology of the Nile is mainly characterized and influenced by high variations in climate and altitude/topography which have a great bearing on flow magnitudes and patterns in the different parts of the basin. These differences are more pronounced in the two tributaries of the Nile; the White and Blue Nile with the White Nile exhibiting relatively steady flows and the Blue Nile exhibiting highly seasonal flows. Presentation of the hydrology of the Nile in this atlas focused on key stations within the sub basins of the Nile starting from down stream to upstream; Main Nile, Tekeze Atbara, Baro Akobo Sobat, White Nile, Bahr el Jebel, Bahr el Ghazal, Albert Nile and ends with Lake Victoria subbasin. There are also swamps and wetlands in the Nile basin which play and influence the hydrology of the Nile mainly the Sudd, Bahr el Ghazal swamps, and the Machar marshes.

As seen in the graphics in this chapter, discharge of the Nile River is highly dependent on the flow patterns from the river tributaries which are principally dependent on rainfall and climate patterns save for areas where infrastructure and regulation influence the downstream flow. Flows from the White Nile are seen to contribute small but more consistent year-round flow.

This chapter presents the water towers of the Nile Basin and an analysis of selected key stations along the Nile followed by the individual sub basins.