THE NILE RIVER is the longest river in the world and flows northward from its sources in eastern Africa toward the Mediterranean Sea. It spans 4,000 miles (6,700 kilometers), beginning at Lake Victoria, which is perched in the highlands of east Africa on the equator and is just one of the three sources of the Nile. The branch of the river that starts from Lake Victoria is known as the White Nile. This branch provides the greatest volume of water to the Nile River as it flows year round. However, not much of the Nile’s waters reach Egypt due to evaporation across the desert.
As the Nile passes through the Sudan, the gradient, or slope, becomes so gradual that the water spreads out to form swamps called sudd. Millions of years ago, long before the Nile found its way out to the Mediterranean Sea, it is believed that there was an inland lake in the Sudan into which the White and Blue Nile used to flow. However, once this lake filled up, the Nile found itself flowing north on its present course to the Mediterranean Sea.
For Egypt, the most important tributary is the Blue Nile, whose source is Ethiopia’s Lake Tana. This tributary, swollen by monsoon rains in the highlands of Ethiopia, has for centuries been the main source of floods to the surrounding valley of the Nile every year between June and September. These floods were heralded by the people along the Nile in Egypt as they brought in rich silt and water for irrigation. It is due to these floods and rich soils that the ancient Egyptian civilization achieved its grandeur. A lesser tributary of the Nile is the Atbara River, which flows from a source in the Ethiopian highlands; it joins the Nile in the vicinity of Khartoum, like the Blue Nile. The Atbara flows only when there is rain in Ethiopia and dries very fast.
The word nile comes from the Greek word neilos, which means “river valley.” The ancient Egyptians called the Nile iteru, meaning “big river.” Indeed, its large size is signified by the expanse of its drainage basin, which covers an area of 1.26 million square miles (3.25 million square kilometers), about 10 percent of the area of Africa. On its flow from Khartoum northwards, the river experiences a series of rapids, or cataracts, as it meets hard igneous rock beyond Aswan in Egypt.
Nubia, the region from Khartoum to Aswan, was the home of the Nubian civilization, which rose thousands of years ago alongside the Egyptian Pharaonic civilization. In Egypt, the river divides the country into two sections, Upper and Lower Egypt. Upper Egypt, also known as southern Egypt, is in the desert plateau from Aswan to Qena. Here, the Nile has dug a deep, wide gorge in the desert plateau. Downstream from Qena the Nile flows northward into the Nile Delta on the Mediterranean Sea. This upstream region (the northern portion of Egypt) is known as Lower Egypt. The Nile Valley’s floodplain covers a total area of 4,250 square miles in a wide canyon before it reaches the Nile Delta, which itself measures some 8,500 square miles.
The delta represents 63 percent of the inhabited area of Egypt, extending about 120 miles (200 km) from south to north and roughly 250 miles (400 km) from east to west; the area supports about 72 million people. Almost all of Egypt’s population is crowded along the Nile Valley and the delta, which comprise only five percent of Egypt’s land. This area is exceptionally productive from the rich alluvial soils, controlled irrigation, and a long tradition of advanced farming practices.
The flow of the Nile is controlled by numerous 20th-century dams. The intense dependence of the Sudan and Egypt on the waters of the Nile has resulted in the building of two large dams, the Sennar Dam on the Blue Nile in the Sudan and the Aswan High Dam in Egypt. The Sennar Dam and others account for 80 percent of the Sudan’s power supply. The Sennar Dam also delivers water to the Gezira plain, irrigating over 2 million acres of land. The Gezira Scheme, one of the most successful agricultural schemes in Africa, was begun in the 1920s under British colonial rule. It was later nationalized by the post-independence Sudanese government in 1956 and the area is now famous for the production of high quality cotton, wheat, and animal feed crops.
Egypt built its own huge dam, the Aswan High Dam, just north of the border between Egypt and the Sudan, which has resulted in the creation of a sizable lake christened Lake Nasser. This lake provides much-needed energy and water for irrigation and ensures that Egypt has some control over the flow of Nile waters toward its more fertile delta near the Mediterranean.
The fact that the Nile flows through several countries, including Uganda, the Sudan, Ethiopia, and Egypt, is a source of both conflict and cooperation. Ethiopia’s population is on the increase and it too wishes to harness the waters of the Blue Nile; Uganda needs the waters of the Nile to generate much-needed energy. Demands on the waters of the Nile are increasing, not only by these four countries but also by others in this region. The fear is that these pressures might result in interstate armed conflict. Already there have been a number of posturing statements and numerous skirmishes between Sudanese and Egyptian troops over the waters of the Nile.
Aswan High Dam; Egypt; Ethiopia; Irrigation; Rivers; Sudan; Uganda.
Feluccas on the Nile River near Luxor in Upper Egypt. Credit:Robert Frerck/Odyssey Productions River, eastern and northeastern Africa. The longe
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