Nile

I

Introduction

Nile, river in northeastern Africa. It is the longest river in the world. The Nile flows from south to north, a distance of 5,584 km (3,470 mi), from its principal source, Lake Victoria, in east-central Africa. It passes through Uganda, Sudan, and Egypt on its way to the Mediterranean Sea. From its remotest source, a mountain stream in Burundi, the river is 6,695 km (4,160 mi) long.

Many rivers feed the Nile on its route to the sea. These rivers are called tributaries. The Nile and its tributaries drain an area of more than 2.8 million sq km (1.1 million sq mi), or nearly one-tenth of the African continent. The Nile carries an enormous amount of silt—particles of sediment, especially mud and clay. It has deposited much of this sediment to form a broad delta that fans out near the river’s mouth. The Nile empties into the Mediterranean Sea through this delta.

On its way to the Mediterranean, the Nile passes by or through nine countries and a variety of landscapes, including mountain highlands, dense rain forests, muddy swamps, grassy savannas, and barren desert. Trees along the banks include acacias, baobabs, date palms, lotuses, and sycamores. The papyrus plant also thrives along the Nile. The Nile crocodile is a ferocious reptile found in the southern part of the Nile, and hippopotamuses spend much of their days lounging and swimming in the Nile. Elephants cool themselves in the swampy Nile waters of southern Sudan. Perch, tilapia, and other fish swim in the Nile.

The life of Egypt has always been centered on the Nile. A great civilization developed there about 5,300 years ago and flourished for 3,000 years. The Nile made the agricultural civilization of ancient Egypt possible. Each year, when the river overflowed its banks, the floodwaters deposited fertile soil in which farmers could grow crops. Only a narrow ribbon of land along the river was suitable for farming. Beyond this arable land lay desert. The water of the Nile was used for irrigating crops (see Irrigation), and it provided a source of fresh water for animals and people. In addition, the Nile was ancient Egypt’s principal thoroughfare: It served as a water highway for traders and travelers. The heritage of ancient Egypt is preserved along the Nile in the form of pyramids, sphinxes, temples, and underground tombs.

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II

Course of the Nile

Although Lake Victoria is regarded as the principal source of the Nile, the river’s ultimate source is considered to be the Ruvyironza River of Burundi in east-central Africa. The Ruvyironza is the most distant tributary of Lake Victoria. The Ruvyironza is a branch of the Kagera River, which follows Tanzania’s borders with Rwanda and Uganda before entering Lake Victoria.

A

From Lake Victoria to Sudan

The Nile leaves Lake Victoria near the now-submerged Ripon Falls of Uganda. It crosses northern Uganda for about 500 km (about 300 mi), passing through Lake Kyoga and then over rapids between rocky walls, until it enters Lake Albert. This section of the Nile, between Victoria and Albert lakes, is called the Victoria Nile. Leaving the northern end of Lake Albert as the Albert Nile, the river flows through northern Uganda and into Sudan.

At the Sudanese border the Albert Nile becomes the Baḩr al Jabal (Baḩr means “river” in Arabic). In south-central Sudan the river flows sluggishly through a vast, swampy lowland known as As Sudd. This unnavigable barrier has historically separated Arab-dominated regions to the north from black African regions to the south. At the river’s junction in Sudan with the Baḩr al Ghazāl, it becomes the White Nile (Baḩr al Abyaḑ).

B

The White Nile and the Blue Nile

Although the White Nile technically forms in Sudan, the name White Nile generally refers to a much longer section of the river: the part that starts in Burundi and enters Lake Victoria. The White Nile is one of the Nile’s two major tributaries. The other is the Blue Nile, which originates at Lake T’ana in the highlands of Ethiopia. The Blue Nile, known as the Abbai in Ethiopia, flows about 1,370 km (about 850 mi) from Lake T’ana to its junction with the White Nile. The rivers get their names from the color of their waters. Although bright blue at its start, the Blue Nile darkens after it reaches Sudan as it picks up black, muddy sediment. The White Nile carries less sediment, and its sediment is generally light gray in color.

The two tributaries—the White Nile and the Blue Nile—meet at Khartoum, the capital of Sudan, to form the wide river we think of as the Nile. North of Khartoum one more river feeds the Nile: the ‘Aţbarah, which originates in the highlands of Ethiopia. The black sediment brought down by the ‘Aţbarah settled in the Nile Delta and made it extremely fertile. North of its meeting with the ‘Aţbarah, the Nile makes a deep S-shaped bend through the Nubian Desert of Sudan. No more tributaries join it before it reaches the Mediterranean.

Downstream from Khartoum, the Nile passes through six cataracts (steep rapids), five in Sudan and one in Egypt, near Aswān. The river enters Egypt through Lake Nasser, a large reservoir formed by the Aswān High Dam. North of the Egyptian capital, Cairo, the river separates into two branches—the Rosetta on the west and the Damietta on the east—and forms the fan-shaped Nile Delta. The two branches of the Nile enter the Mediterranean Sea through this delta, which is 250 km (160 mi) wide.

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