Nile

I

Introduction

Nile, river, eastern Africa, the longest river in the world. From Lake Victoria in east central Africa, it flows generally north through Uganda, Sudan, and Egypt to the Mediterranean Sea, for a distance of 5,584 km (3,470 mi). From its remotest headstream, the Luvironza River in Burundi, the river is 6,695 km (4,160 mi) long. The river basin has an area of about 3,350,000 sq km (1,293,000 sq mi). Its average discharge is 3.1 million litres (680,000 gallons) per second. The lower course of the river in Egypt has become centrally important to tourism, linking as it does all the major sites of Egyptian antiquity (see Ancient Egypt).

II

Course of the Nile

The Luvironza is one of the upper branches of the Kagera River in Tanzania. The Kagera follows the boundary of Rwanda northwards, turns along the boundary of Uganda, and drains into Lake Victoria, which lies at a height of 1,134 m (3,717 ft) above sea level. On leaving Lake Victoria at the site of the now-submerged Ripon Falls, the Nile rushes for 483 km (300 mi) between high rocky walls and over rapids and cataracts, at first north-west and then west, until it enters Lake Albert. The section between the two lakes is called the Victoria Nile. The river leaves the northern end of Lake Albert as the Albert Nile, flows through northern Uganda, and at the Sudan border becomes the Bahr al-Jabal. At its junction with the Bahr al-Ghazal, the river becomes the Bahr al-Abyad, or the White Nile. Various tributaries flow through the Bahr al-Ghazal district.

At Khartoum the White Nile is joined by the Blue Nile, or Bahr al-Azraq. These are so named because of the colour of the water. The Blue Nile, 1,529 km (950 mi) long, gathers its volume mainly from Lake Tana, in the Ethiopian Highlands; it is known here as the Abbai. From Khartoum the Nile flows north-east; 322 km (200 mi) below that city, it is joined by the Atbara River. The black sediment brought down by this river settles in the Nile delta and makes it very fertile. During its course from the confluence of the Atbara through the Nubian Desert, the river makes two deep bends. Below Khartoum navigation is rendered dangerous by cataracts, the first occurring north of Khartoum and the sixth near Aswān. The Nile enters the Mediterranean Sea by a delta that separates into the Rosetta and Damietta distributaries.

III

History

Along with the Tigris, Euphrates, and Indus, the lower course of the Nile fostered one of the world's earliest civilizations, dating back to the sixth millennium bc. Its annual flooding created the fertile plains upon which the people of ancient Egypt depended, and it became their main artery of communication and commerce, as well as being central to their spiritual life.

Noted Western explorers of the Nile include the British explorers Sir Richard Francis Burton, who led the expedition which discovered the source of the Nile, John Hanning Speke, who reached Lake Victoria in 1858 and Ripon Falls in 1862, and Sir Samuel White, who sighted Lake Albert in 1864; a German, Georg August Schweinfurth, who explored (1868-1871) the western feeders of the White Nile; and a British-American, Sir Henry Morton Stanley. In 1875 Stanley sailed around Lake Victoria; in 1889 he traced the Semliki River and reached Lake Edward and the Ruwenzori Range.

IV

Nile Dams

The first dam on the Nile, the Aswān Dam, was built in 1902 and heightened in 1936. The Aswān High Dam was dedicated in 1971; it impounds one of the world's largest reservoirs, Lake Nasser. A negative aspect of the damming is to reduce the flow of sediment to the lower Nile, on which that region depends for its fertility. The Makwar Dam, now called the Sannār Dam, was built across the Blue Nile south of Khartoum following World War I to provide storage water for cotton plantations in the Sudan. A dam at Jabal Awliya was constructed on the White Nile south of Khartoum in 1937.