Nile
The Nile River is a major north-flowing river in northeastern Africa which flows into the Mediterranean Sea. At long, it is the longest river in the world, although the volume of water it carries is much smaller than other major rivers such as the Amazon or Congo. Its drainage basin covers portions of eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, Sudan, and Egypt. It plays an important economic role in the economy of these nations, and it is the primary water source for South Sudan, Sudan and Egypt.
The Nile has two major tributaries: the White Nile and the Blue Nile. The White Nile, being longer, is considered to be the headwaters, although the Blue Nile contributes 80% of the water and silt below the confluence of the two. The White Nile begins at Lake Victoria and flows through Uganda and South Sudan, while the Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet at the Sudanese capital of Khartoum. After Khartoum the river flows north, almost entirely through the Nubian Desert, to Cairo and its large delta, joining the Mediterranean Sea near Alexandria.
Egyptian civilization and Sudanese kingdoms have depended on the river and its annual flooding since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of the Aswan Dam. Nearly all the cultural and historical sites of Ancient Egypt developed and are found along river banks. The Nile is, with the Rhône and Po, one of the three Mediterranean rivers with the largest water discharge.
Names and etymology
The English word Nile is derived from the from the Latin Nilus and the Ancient Greek Νεῖλος, which probably originated from the Semitic term naḥal, meaning "river".In the ancient Egyptian language, the Nile was called Ar or Aur, meaning 'black', probably in reference to the dark color of the Nile floodwaters as they carried sediment from upriver.
In the modern era, within the Nile Basin, the river goes by several names. In Egypt, its names use the Arabic word النيل in forms such as Al-Nīl, Baḥr Al-Nīl or Nahr Al-Nīl. In South Sudan, it is sometimes referred to by the Arabic 'Baḥr el-Jebel', بحر الجبل, literally 'Mountain River'. In Uganda, the speakers of Luganda use the name Kiyira. Some Nubian peoples of Egypt and Sudan use the Nobiin name Áman Dawū. The Coptic language in Egypt, which is no longer spoken, but still used for liturgical purposes, refers to the river as ⲫⲓⲁⲣⲟ.
Physical geography
The Nile River is a major river in northeastern Africa which flows into the Mediterranean Sea. Its drainage basin includes portions of eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, Sudan, and Egypt. The basin covers a wide variety of climates, ecosystems, and topographies.Regions of the Nile Basin
The Nile Basin can be divided into seven regions; five of these regions encompass the longest course of the Nile River. Proceeding in a downstream sequence, these five regions are: the African Great Lakes, the Mountain Nile, the White Nile, the main Nile, and the Nile Delta. Two additional regions encompass major tributaries: the Blue Nile and the Atbarah River.African Great Lakes
The African Great Lakes region contains the source of the Nile river as well as several large lakes that are part of the Nile river system: Lake Victoria, Lake Albert, Lake George, and Lake Edward. The source of the Nile is the Rukarara River within Rwanda's Nyungwe National Park, and it leads to the Kagera River, which drains into Lake Victoria. Although it is a large lakethe second-largest freshwater lake in the world Lake Victoria is relatively shallow. The Nile river first assumes the name "Nile" where Lake Victoria empties on its north side: the course from there to Lake Albert is called the Victoria Nile. A pair of waterfalls Ripon Falls and Owen Falls were located where the Nile exits Lake Victoria, but have both been submerged by the construction of the Nalubaale dam. After Bujagali Falls and Bujagali Power Station, the Victoria Nile empties into Lake Kyoga. After exiting Lake Kyoga, the river is joined by the River Kafu tributary, then passes over Murchison Falls and flows into Lake Albert. Unlike Lake Victoria, Lake Albert is a deep lake surrounded by mountains. The river exits Lake Albert on its north shore, where it is called the Albert Nile; this stretch of the river is relatively flat and broad, and suitable for navigation by steamboats.Mountain Nile
The second region of the Nile Basin, proceeding downstream, is the Mountain Nile. This region begins near the town of Nimule and extends to Lake No, and is entirely within South Sudan. After passing through Nimule, the river goes through the Fula Rapids and on to Jubathe capital city of South Sudan. After Juba, the Nile passes through the town of Bor, then enters the Sudd, a large swamp located in a flat plain. The slope of the ground in the Sudd is only 1:13,000, so the river slows down and widens. Lush vegetation, including sedges, papyrus, and common water hyacinth clog the waterways and make navigation difficult. At the downstream edge of the Sudd swamp, the Nile is joined by the Bahr el Ghazal River a tribuatary flowing from the west. This confluence happens in Lake No.White Nile
Continuing downstream, the third region of the Nile Basin is the White Nile region. About 140 km after Lake No, the swamps diminish near the city of Malakal, and the river enters a long, placid stretch extending to Khartoum, where it is joined by the Blue Nile near Khartoum, the capital of Sudan.Main Nile
The fourth region of the Nile Basinthe main Nileextends from Khartoum to Cairo, the capital of Egypt. Soon after leaving Khartoum, the river goes enters the Sabloka Nature Reserve and goes through the sixth of the renowned six cataracts of the Nile. The Atbarah Rivera major tributaryjoins the Nile, which then follows a large S-shape curve to the west. Four more cataracts are encountered in this large S-curve, which render the river unnavigable, although ships may travel between the cataracts. The river then enters a large reservoir, Lake Nasser. This lake the world's second largest man-made lakewas formed when the Aswan High Dam was built in Egypt, and inundates more than 480 km of the Nile river. A second dam, older and smaller, lies beneath the Aswan High Dam, near the location of the first Nile cataract. From these dams, the Nile flows about 800 km through a limestone plateau, bordered by large amounts of irrigated farmland, until it reaches Cairo.Nile Delta
The fifth, and final, region encompassing the Nile river is the Nile Delta, a large triangular river delta that extends from Cairo to the Mediterranean Sea. The river splits into two major distributaries within the delta: the Rosetta branch and the Damietta branch. The soil in the delta ranges from 15 to 22 meters thick, and the total volume is about 150,000 km. The delta was created over several million years, built-up from soil carried down the river from the Ethiopian Highlands. Since the Aswan High Dam was completed in 1970, the delta has begun to shrink due erosion caused by currents in the Mediterranean Sea. In the past, erosion was balanced by new soils arriving in the form of sediment carried by the river; but the dam traps sediment in its reservoir, preventing new soil from reaching the delta.The final two regions of the Nile Basin are the Blue Nile basin and the Atbarah River basin, both discussed in the [|section on Tributaries].
Tributaries
The longest course of the Nile, which includes the White Nile tributary, has several other tributaries that feed into it.Blue Nile
The Blue Nile springs from hills in Ethiopia where it originates as a stream named Abay near the town of Gish Abay: Gish in an Amharic word meaning 'source', and Abay is the name of the stream. Gish Abay flows into Lake Tana, a large, shallow lake, which has a single outflow where it adopts the 'Blue Nile' name. The Blue Nile travels south, then north passing through South Sudan into Sudan, where it joins with the White Nile at Khartoum to form the main Nile. Along its course, the Blue Nile generates electricity at several hydro power plants, including the Tisabay hydropower project at the Blue Nile Falls, the Grand Ethiopian Renaissance Dam near the border between Ethiopia and South Sudan, the Roseires Dam near town of Ad Damazin, and the Sennar Dam. The size of the Blue Nile's drainage basin is over 306,000 square km.Atbarah River
The Atbarah River is a tributary of the Nile which arises in northern Ethiopia, and joins the Nile about 320 km north of Khartoum. Its drainage basin covers over 204,000 square km. The Atbarah has a heavy flow during and following the monsoon season in Ethiopia, but can dry up in the winter and spring. Despite the intermittent nature of the river, it provides more than 10% of the total annual flow of the Nile. Dams on the Atbarah include the Khashm el-Girba Dam, the Upper Atbara and Setit Dam Complex, and the Tekezé Dam.Bahr el Ghazal and Sobat River
The Bahr al Ghazal and the Sobat River are two tributaries of the White Nile. The Bahr el Ghazal arrives from the west, joining the White Nile at Lake No. The drainage basin of the Bahr el Ghazal river is largeabout 860,000 square kmand receives a relatively large amount of rain, but its contribution to the Nile is insignificant. The basin includes Lake Kundi and Lake Keilak. The Bahr el Ghazal passes through the city of Wau, South Sudan: it is a permanent stream east of Wau, but a seasonal stream to the west.Another tributary, the Sobat River, joins the White Nile near the town of Malaka. Its basinwhich includes the Machar Marshescovers about 225,000 square km. The Sobat floods between July and December.