The Nile is one of the world’s great waterways, with a length of 4,180 miles (6,695 kilometers), and is one of the most culturally significant natural formations in human history. It flows northward from remote headwaters in Ethiopia and central Africa and flows into the Mediterranean Sea. The Nile has flooded seasonally for millennia to provide Egypt’s people with life-giving lush soil and irrigation. The Nile’s drainage basin covers roughly 10% of Africa’s land area.
The Nile, like the Tigris and Euphrates rivers in Mesopotamia, also known as modern Iraq, offered a favorable environment for the formation of one of history’s first and most powerful civilizations. The river and its yearly floods were significant in ancient Egyptian mythology and cosmology. Since ancient times, most of Egypt’s population and towns, with the exception of those along the shore. They also have been concentrated along the Nile valley north of Aswan. Nearly all of ancient Egypt’s cultural and historical sites can be found along its banks.
In recent times, the ten Nile Basin nations face possibly their greatest challenge as they deal with. Especially issues with increasing demands for water, economic prospects, and hydroelectric power. Basically all ten Nile basin countries signed a 1999 agreement to achieve sustainable socio-economic development through the equitable utilization of, and benefit from the common Nile Basin water resources. Only in response to their growing populations and water needs, as well as projected drops in water flow as a result of climate change.
The Nile and its geography
The name “Nile” is derived from the Greek word Neilos, which means “river valley.” The Nile is rather known as iteru in ancient Egyptian, which means “big river,” as indicated by the hieroglyphs on the right.
There are two primary tributaries of the Nile. Although the Blue Nile provides the majority of the Nile’s water and fertile soil, the White Nile is the longest of the two. The White Nile rises in central Africa’s Great Lakes region. Then also with the most distant source in southern Rwanda. It flows north through Tanzania, Lake Victoria, Uganda, and southern Sudan. The Blue Nile begins in Ethiopia at Lake Tana and flows southeast into Sudan. The two rivers merge near Khartoum, Sudan’s capital.
Both branches are located on the western flanks of the Eastern Rift, which is located in the southern part of the Great Rift Valley. The Atbara is another minor tributary that flows only when there is rain in Ethiopia and dries quickly. The Nile is unique in that its final tributary (the Atbara) joins it approximately halfway to the sea. Evaporation causes the Nile to decline north of that point.
The Nile divides into two branches north of Cairo, both of which discharge into the Mediterranean Sea: the Rosetta Branch to the west and the Damietta Branch to the east, forming the Nile Delta.
White Nile
The Nile’s source is sometimes thought to be Lake Victoria, however the lake contains several large feeder rivers. The most distant stream flows from Nyungwe Forest in Rwanda to Lake Victoria in Tanzania via the Rukarara, Mwogo, Nyabarongo, and Kagera rivers.
The Victoria Nile emerges from Lake Victoria at Ripon Falls, in Jinja, Uganda. It runs for another 300 miles (500 kilometers) past Lake Kyoga before reaching Lake Albert. The river becomes known as the Albert Nile after leaving Lake Albert. It then flows into Sudan and is known as the Bahr al Jabal (“River of the Mountain”). The river becomes known as the Bahr al Abyad, or the White Nile, at the junction of the Bahr al Jabal and the Bahr al Ghazal, which is 445 miles (720 kilometers) long, due to the whitish clay suspended in its waters. The river then flows to Khartoum.
The White Nile generates around 31 percent of the yearly Nile discharge. During the dry season (January to June), the White Nile contributes between 70 and 90 percent of total Nile discharge.
Blue Nile
The Blue Nile rises in the Ethiopian highlands and flows approximately 850 miles (1,400 kilometers) to Khartoum. (Including sections that are funneled at high speed via a small, rocky valley.) The Nile is formed when it joins the White Nile. Ethiopia provides 90 percent of the water and 96 percent of the transportable sediment carried by the Nile, with the Blue Nile providing 59 percent of the water. (The rest comes from the Tekezé, Atbarah, Sobat, and tiny tributaries). However, silt erosion and transportation occur only during the Ethiopian rainy season in the summer, when rainfall is unusually high on the Ethiopian plateau.
Cataracts and Great Bend
The Nile between Khartoum and Aswan is defined by two features: cataracts and the Great Bend. Cataracts have prohibited boats from traveling up and down the Nile between Equatorial Africa and Egypt since Roman times, and the huge marshes on the upper Nile south of Khartoum have hidden the Nile’s sources in obscurity for millennia.
Although six are listed, there are many more. The cataracts are particularly important because they delineate river segments where granite and other hard rocks drop to the Nile’s edge. Because the floodplain is narrow to nonexistent, agricultural prospects are limited. This section of the Nile is sparsely populated due to two factors: navigational difficulties and a limited floodplain. The First Cataract at Aswan is located between Egypt in the north and Nubia or Sudan in the south.
The Great Bend is one of the Nile’s most unexpected characteristics. The Nile marches relentlessly north for the majority of its route, but in the heart of the Sahara Desert, it bends southwest and flows away from the sea for 300 kilometers before resuming its northward trip. The river’s channel has been shifted due to the tectonic upheaval of the Nubian Swell. This uplift is also responsible for cataracts. If not for the recent uplift, the abrasive action of the sediment-laden Nile would have quickly diminished these rocky portions.
Hydrology
The ancients were perplexed as to why the volume of water flowing down the Nile in Egypt varied so dramatically over the course of a year, especially because nearly little rain fell there. We now have hydrographic data that explains why the Nile is known as a “summer river.”
South of Great Bend in Sudan, the Nile has two hydraulic regimes. Because its flow is twice buffered, the White Nile maintains a consistent flow throughout the year. The water stored in the Central African lakes of Victoria and Albert, as well as evaporation losses in the Sudd. Also the world’s biggest freshwater marsh, moderate seasonal changes. The Sudd minimizes yearly changes in streamflow because the area of the Sudd grows in abnormally wet years, resulting in greater losses to evaporation than in dry years when the area of the Sudd decreases.
The hydraulic regime of the Blue Nile/Atbara system is radically different. It responds to the Ethiopian highlands’ wet/dry season fluctuation. These rivers dry up throughout the winter when there is minimal rain in the highlands. In the summer, moist winds from the Indian Ocean chill the Ethiopian highlands as they deliver torrential rains that fill the dry washes and canyons with flowing water that eventually joins the Blue Nile or the Atbara. During the summer, the White Nile makes a negligible contribution. The annual flood in Egypt is a gift from Ethiopia’s annual monsoon.
Less Water
There is less water after Aswan due to the evaporation of the Nile’s waters during its unhurried journey through the Sahara Desert. Water is also lost as a result of human activity, therefore less water flows in the Nile from Atbara, the Nile’s last tributary, all the way to the Mediterranean Sea.
Prior to the construction of dams on the river, peak flows occurred in late August and early September. Especially with minimum flows occurring in late April and early May.
