Blue Nile

Blue Nile (Arabic, al-Bahr al-Azraq), river, north-eastern Africa, about 1,370 km (850 mi) long. It rises at an altitude of about 1,830 m (6,000 ft) in the region of Lake Tana, north-western Ethiopia, flows south and then west in Ethiopia, and follows a north-western 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.