Nile - Geography.

Nile - Geography. 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. 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 Ba? r al Jabal (Ba? r 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 Ba?r al Ghaz?l, it becomes the White Nile (Ba? r al Abya? ). 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 'A?barah, which originates in the highlands of Ethiopia. The black sediment brought down by the 'A?barah settled in the Nile Delta and made it extremely fertile. North of its meeting with the 'A?barah, 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 Asw?n. The river enters Egypt through Lake Nasser, a large reservoir formed by the Asw?n 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. III ECONOMIC IMPORTANCE OF THE NILE Irrigation along much of the Nile supports agriculture in the river basin. Nearly all the food produced in Egypt is watered by the Nile, and much of the country's population lives in the river valley. Irrigation from waters of the Nile is extensive in Sudan, as well, especially in a fertile area between the Blue Nile and the White Nile known as the Gezira (Arabic for "island"). Farmers in the Nile valley grow products such as cotton, wheat, sorghum, dates, citrus fruits, sugarcane, and various legumes. Communities along the river catch tilapia, Nile perch, and other freshwater fish in its waters. As a result of the Asw? n High Dam, which was completed in 1970, the Nile no longer floods its banks each summer, swollen by heavy spring rains in the Ethiopian highlands. The dammed waters are stored in Lake Nasser and released gradually to enable farmers to irrigate their crops year-round. However, the nutrient-rich sediments carried by the Nile now collect behind the dam and no longer enrich the soil of the Nile valley and the Nile delta. The soil has become less fertile as a consequence, and farmers must now use fertilizer. Ferries and barges carry people across the Nile at various points in Egypt and Sudan as well as across Lakes Nasser and Victoria. Sightseeing boats and cruise ships transport tourists to ancient Egyptian sites along the river, especially to the pyramids at Giza, the temples at Luxor and Al Karnak near ancient Thebes, and the temple of Ab? Simbel south of Asw?n. However, the Nile no longer serves as a major transportation route. Trucks and railroads carry most of the cargo in Egypt and Sudan, and most of the Nile River ports have shut down or fallen into disrepair. Efforts were under way in the early 2000s to improve port facilities along the Nile in northern Egypt. The Nile is also a source of hydroelectric power (see Waterpower), although the river's potential as a source of electricity has yet to be fully exploited. Dams to provide hydroelectricity (and control flooding) have been constructed along the Nile in Egypt, Sudan, and Uganda. Additional hydroelectric projects are planned. IV HISTORY OF THE NILE A Ancient Egypt and the Nile The first great African civilization developed in the northern Nile Valley in Egypt in about 3300 BC. Settlements along the Nile date back even farther. Dependent on agriculture, ancient Egypt relied on the flooding of the Nile for irrigation and new soils. The ancient Egyptian capitals of Memphis and Thebes rose in the river valley, as did the tombs of ancient Egypt's kings and queens, including the pyramids at Giza. Royal burial ceremonies took place on the river. Egyptian rule extended south over the kingdom of Kush in the Nubia region of northern Sudan. Ruled by Egypt for about 1,800 years, Kush subjugated Egypt in the 8th century BC. Temples, tombs, and other monuments of these civilizations blanket the river valley in Egypt and northern Sudan. B Search for the Source of the Nile Until the middle of the 1800s, the source of the Nile was a great mystery. Ancient Greeks wrote that the river originated in snowcapped highlands. Noted British explorers John Hanning Speke and Sir Richard Burton reached Lake Tanganyika in 1857, which Burton believed was the source of the Nile. The following year Speke went on to Lake Victoria, and correctly claimed it was the main source of the Nile. Another British explorer, Samuel White Baker, sighted Lake Albert in 1864, and German explorer Georg August Schweinfurth explored the Ba? r al Ghaz? l between 1868 and 1871. An Anglo-American, Henry Morton Stanley, circumnavigated Lake Victoria in 1875 and explored Lake Edward and the Ruwenzori Range in 1889. C European Control of the Nile Basin European powers gained control over most of the countries of the Nile basin in the late 19th century. Britain established its power in Egypt, Sudan, Uganda, and Kenya; Germany ruled what are now Tanzania, Rwanda, and Burundi; and Belgium governed what is now the Democratic Republic of the Congo (formerly Zaire). After World War I (1914-1918) German territory was divided between Britain and Belgium, with Britain controlling Tanzania, and Belgium gaining Rwanda and Burundi. Ethiopia remained an independent state. European power in Egypt and Sudan ended in the 1950s and elsewhere in the 1960s. D Damming the Nile To raise water levels for irrigation, several barriers were built across the Egyptian Nile in the late 19th century. The first dam on the Nile was built at Asw?n in Egypt in 1902 and later heightened. The Sennar Dam was built across the Blue Nile south of Khartoum following World War I to provide irrigation water for Sudanese cotton plantations. Hydroelectric dams were constructed at Jabal al Awliy? ' on the White Nile in Sudan (1937), Owen Falls in Uganda (1954), and Roseires on the Blue Nile in Sudan (1962). By the 1950s it had become clear that the Asw?n Dam was inadequate to control the Nile, and a new dam, the Asw?n High Dam, was constructed several miles upstream. Although the dams now control the Nile flooding, they have drastically reduced the deposits of sediment and the fertility of the valley and the delta. The environmental impact of the dams has been profound, as stretches of the river above the dams have become clogged with silt, and decreased flooding has led to increased erosion and greater salt content in the soil and water of the delta. Local communities and ancient sites in Egypt and Sudan were either submerged or relocated because of the dams. E Control over the Nile Waters Who controls the Nile has long been a source of conflict for the countries dependent on its waters. Egypt claims historic dominance, but eight other countries share the Nile: Burundi, Democratic Republic of the Congo (DRC), Ethiopia, Kenya, Rwanda, Sudan, Tanzania, and Uganda. These countries are poor and lack sufficient food to feed their growing populations. Some of them suffer from periodic drought. They are anxious to utilize the Nile for irrigation and, in some cases, for producing hydroelectricity, as well. The Nile Basin Initiative was launched in 1999 to establish regional cooperation among the countries who share the Nile. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.