Blue Nile

Blue Nile (Arabic Al Baḩr al Azraq), river in northeastern Africa, 1,370 km (850 mi) long. It rises at an altitude of 1,830 m (6,000 ft) in the region of Lake T’ana, in northwestern Ethiopia, flows south and then west in Ethiopia, and follows a northwestern course in Sudan before merging, at Khartoum, with the White Nile to form the Nile proper. The Blue Nile, which contributes about two-thirds of the water of the Nile, is known as the Abbai in Ethiopia, where it, in part, flows through a deep gorge. The river is dammed for irrigation and hydroelectricity production in Sudan.