Blue Nile

River rising at a spring site upstream of Lake Tana in Ethiopia, 2,150 m/7,054 ft above sea level. Flowing west then north for 1,460 km/907 mi, it eventually meets the White Nile at Khartoum. For a length of 800 km/500 mi it is navigable at high water. Some 80% of Sudan's electricity is provided by hydroelectric schemes at Roseires and Sennar, and these dams provide irrigation water for over 10,000 sq km/3,860 sq mi of the Gezira Plain.

In Ethiopia the Blue Nile is called Abai (or Abay or Abbai). In ancient times the Blue Nile, which supplies the bulk of the Nile's waters, was temporarily diverted by the Ethiopians, thus cutting off the greater part of Egypt's vital water supply. The Blue Nile is of immense strategic importance to Ethiopia and is the historical cause of Egyptian aspirations in respect of Ethiopia.