TheNile^[b] (also known as theNile River orRiver Nile) is a major north-flowingriver in northeasternAfrica. It flows into theMediterranean Sea. The Nile is the longest river in Africa. It has historically been considered thelongest river in the world,^[3][4]though this has been contested by research suggesting that theAmazon River is slightly longer.^[5][6]Of the world's major rivers, the Nile has one of the lowest average annual flow rates.^[7]About 6,650 km (4,130 mi)^[a] long, itsdrainage basin covers eleven countries: theDemocratic Republic of the Congo,Tanzania,Burundi,Rwanda,Uganda,Kenya,Ethiopia,Eritrea,South Sudan,Sudan, andEgypt.^[9]In particular, the Nile is the primary water source of Egypt, Sudan and South Sudan.^[10]In these countries it is an important economic factor in agriculture and fishing.

Nile River
Nile in Cairo, Egypt
Etymology	"The river"
Location
Countries	Egypt, Sudan, South Sudan, Ethiopia, Uganda, Democratic Republic of the Congo, Kenya, Tanzania, Rwanda, Burundi
Major cities	Jinja,Juba,Khartoum,Cairo
Physical characteristics
Source	White Nile
• coordinates	02°16′56″S29°19′53″E / 2.28222°S 29.33139°E /-2.28222; 29.33139
• elevation	2,400 m (7,900 ft)
2nd source	Blue Nile
• location	Lake Tana, Ethiopia
• coordinates	12°02′09″N037°15′53″E / 12.03583°N 37.26472°E /12.03583; 37.26472
Mouth	Mediterranean Sea
• location	Nile Delta, Egypt
• coordinates	30°10′21″N31°8′24″E / 30.17250°N 31.14000°E /30.17250; 31.14000
• elevation	Sea level
Length	6,650 km (4,130 mi)[a]
Basin size	3,349,000 km2 (1,293,000 sq mi)
Width
• maximum	2.8 km (1.7 mi)
Depth
• average	8–11 m (26–36 ft)
Discharge
• location	Aswan, Egypt
• average	2,633 m3/s (93,000 cu ft/s)
• minimum	530 m3/s (19,000 cu ft/s)
• maximum	7,620 m3/s (269,000 cu ft/s)
Discharge
• location	Cairo, Egypt
• average	2,000 m3/s (71,000 cu ft/s)
• minimum	500 m3/s (18,000 cu ft/s)
• maximum	7,000 m3/s (250,000 cu ft/s)
Discharge
• location	Nile Delta, Egypt, Mediterranean Sea
• average	1,584 m3/s (55,900 cu ft/s)
Basin features
Tributaries
• left	White Nile
• right	Blue Nile,Atbara

The Nile has two majortributaries: theWhite Nile and theBlue Nile. The White Nile, being the longer, is traditionally considered to be theheadwaters stream, while the Blue Nile actually contributes 80% of the water andsilt below theconfluence of the two. The White Nile rises in theGreat Lakes region. It begins atLake Victoria and flows through Uganda and South Sudan. The Blue Nile begins atLake Tana in Ethiopia^[11] and flows into Sudan from the southeast. The tworivers meet at the Sudanese capital ofKhartoum.^[12]

After Khartoum the river flows north, almost entirely through theNubian Desert, toCairo and itslarge delta, joining the Mediterranean Sea atAlexandria.Egyptian civilization andSudanese 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 theAswan Dam. Nearly all the cultural and historical sites ofAncient Egypt developed and are found along river banks. The Nile is, with theRhône andPo, one of the three Mediterranean rivers with the largestwater discharge.^[13]

The standard English names "White Nile" and "Blue Nile" refer to the river's source, derived fromArabic names formerly applied to only the Sudanese stretches that meet atKhartoum.^[14]

In the ancientEgyptian language, the Nile is calledḤꜥpy (Hapy) orJtrw (Iteru), meaning "river". InCoptic, the wordⲫⲓⲁⲣⲟ, pronouncedpiaro (Sahidic) orphiaro (Bohairic), means "the river" (lit. p(h).iar-o "the.canal-great"), and comes from the same ancient name.^[15] InNobiin, the river is calledÁman Dawū, meaning "the great water".^[2] InLuganda, the river is calledKiira orKiyira. InRunyoro, it is calledKihiira. InEgyptian Arabic, the Nile is calleden-Nīl, while inStandard Arabic it is calledan-Nīl. InBiblical Hebrew, it isהַיְאוֹר‎,Ha-Ye'or orהַשִׁיחוֹר‎,Ha-Shiḥor.

The English nameNile and the Arabic namesen-Nîl andan-Nîl both derive from theLatinNilus and theAncient GreekΝεῖλος.^[16][17] Beyond that, however, the etymology is disputed.^[17][18]Homer called the riverΑἴγυπτος,Aiguptos, but in subsequent periods, Greek authors referred to its lower course asNeilos; this term became generalized for the entire river system.^[19] Thus, the name may derive from Ancient Egyptian expressionnꜣrꜣw-ḥꜣw(t) (lit. 'the mouths of the front parts'), which referred specifically to the branches of the Nile transversing the Delta, and would have been pronouncedni-lo-he in the area aroundMemphis in the 8th century BCE.^[19]Hesiod at hisTheogony refers toNilus (Νεῖλος) as one of theriver gods, son ofOceanus andTethys.^[20]

Another derivation ofNile might be related to the termNil (Sanskrit:नील,romanized: nila;Egyptian Arabic:نيلة),^[15] which refers toIndigofera tinctoria, one of the original sources ofindigo dye.^[21]Another may beNymphaea caerulea, known as "The Sacred Blue Lily of the Nile", which was found scattered overTutankhamun's corpse when it was excavated in 1922.^{[22][citation needed]} Another possible etymology derives from theSemitic termNahal, meaning "river".^[23]Old Libyan has the termlilu, meaning water (in modern Berberilel ⵉⵍⴻⵍ meanssea).^[24]

With a total length of about 6,650 km (4,130 mi)^[a] between the region ofLake Victoria and theMediterranean Sea, the Nile is among the longest rivers on Earth. Thedrainage basin of the Nile covers 3,254,555 square kilometers (1,256,591 sq mi), about 10% of the area of Africa.^[26] Compared to other major rivers, though, the Nile carries little water (5% of that of theCongo River, for example).^[27] The Nile basin is complex, and because of this, thedischarge at any given point along themain stem depends on many factors including weather, diversions,evaporation andevapotranspiration, andgroundwater flow.

Upstream fromKhartoum (to the south), the river is known as theWhite Nile, a term also used in a limited sense to describe the section betweenLake No and Khartoum. At Khartoum, the river is joined by theBlue Nile. The White Nile starts in equatorial East Africa, and the Blue Nile begins in Ethiopia. Both branches are on the western flanks of theEast African Rift.

The source of the Blue Nile isLake Tana^[28] in theGish Abay region^[29] in theEthiopian Highlands.^[30][31]

The source of the White Nile, even after centuries of exploration, remains in dispute. The most remote source that is indisputably a source for the White Nile is of theKagera River; however, the Kagera has multiple tributaries that are in contention for the farthest source of the White Nile. Two start in Burundi: theRuvyironza River (also known as the Luvironza) and theRurubu River.^[32][31] In addition, in 2010, an exploration party in Rwanda^[33] went to a place described as the source of theRukarara tributary,^[34] and by hacking a path up steep jungle-choked mountain slopes in theNyungwe Forest found (in thedry season) an appreciable incoming surface flow for many kilometres upstream, thence finding a new source, giving the Nile a length of 6,758 km (4,199 mi).^{[citation needed]}

The White Nile leavesLake Victoria atRipon Falls nearJinja, Uganda, as the "Victoria Nile." It flows north for some 130 kilometers (81 mi) toLake Kyoga. The last part of the approximately 200 kilometers (120 mi) river section starts from the western shores of the lake and flows at first to the west until just south ofMasindi Port, where the river turns north, then makes a great half circle to the east and north toKaruma Falls. For the remaining part, it flows westerly through theMurchison Falls until it reaches the northern shores ofLake Albert where it forms a significant river delta. Lake Albert is on the border of the Democratic Republic of the Congo, but the Nile is not a border river at this point. After leaving Lake Albert, the river continues north through Uganda and is known as theAlbert Nile.

The White Nile flows into South Sudan just south ofNimule, where it is known as theBahr al Jabal ("Mountain River"^[35]). Just south of the town is theconfluence with theAchwa River. TheBahr al Ghazal, 716 kilometers (445 mi) long, joins the Bahr al Jabal at a small lagoon calledLake No, after which the Nile becomes known as theBahr al Abyad, or the White Nile, from the whitishclay suspended in its waters. When theNile floods it leaves a rich silty deposit which fertilizes the soil. The Nile no longer floods in Egypt since the completion of theAswan Dam in 1970. Ananabranch river, theBahr el Zeraf, flows out of the Nile's Bahr al Jabal section and rejoins the White Nile.

The flow rate of the Bahr al Jabal atMongalla is almost constant throughout the year and averages 1,048 m³/s (37,000 cu ft/s). After Mongalla, the Bahr Al Jabal enters the enormous swamps of theSudd region. More than half of the Nile's water is lost in this swamp toevaporation andtranspiration. The average flow rate of the White Nile at the tails of the swamps is about 510 m³/s (18,000 cu ft/s). From here it meets with theSobat River atMalakal. On an annual basis, the White Nile upstream of Malakal contributes about 15% of the total outflow of the Nile.^[36]

The average flow of the White Nile at Lake Kawaki Malakal, just below the Sobat River, is 924 m³/s (32,600 cu ft/s); the peak flow is approximately 1,218 m³/s (43,000 cu ft/s) in October and minimum flow is about 609 m³/s (21,500 cu ft/s) in April. This fluctuation is caused by the substantial variation in the flow of the Sobat, which has a minimum flow of about 99 m³/s (3,500 cu ft/s) in March and a peak flow of over 680 m³/s (24,000 cu ft/s) in October.^[37] During thedry season (January to June) the White Nile contributes between 70% and 90% of the total discharge from the Nile.

BelowRenk, the White Nile enters Sudan, it flows north to Khartoum and meets the Blue Nile.

The course of the Nile in Sudan is distinctive. It flows oversix groups of cataracts, from the sixth atSabaloka just north of Khartoum northward toAbu Hamad. The tectonic uplift of theNubian Swell diverts the river south-west for over 300 km, following the structure of theCentral African Shear Zone embracing theBayuda Desert. AtAl Dabbah it resumes its northward course towards the first cataract atAswan forming the S-shaped Great Bend of the Nile^[38] mentioned byEratosthenes.^[39]

In the north of Sudan, the river entersLake Nasser (known in Sudan as Lake Nubia), the larger part of which is in Egypt.

Below theAswan Dam, at the northern limit of Lake Nasser, the Nile resumes its historic course. North ofCairo, the Nile splits into two branches (or distributaries) that feed the Mediterranean: theRosetta Branch (an anglicized version of the nameRashid) to the west and theDamietta to the east, forming theNile Delta.

The annual sediment transport by the Nile in Egypt has been quantified.^[40]

• AtAswan: 0.14 million tonnes ofsuspended sediment and an additional 28% ofbedload
• AtBeni Sweif: 0.5 million tonnes of suspended sediment and an additional 20% of bedload
• AtQena: 0.27 million tonnes of suspended sediment and an additional 27% of bedload
• AtSohag: 1.5 million tonnes of suspended sediment and an additional 13% of bedload

Below the confluence with the Blue Nile the only major tributary is theAtbarah River, also known as the Red Nile. Roughly halfway to the sea, it originates in Ethiopia north ofLake Tana, and is around 800 kilometers (500 mi) long. The Atbarah flows only while there is rain in Ethiopia and dries very rapidly. During the dry period of January to June, it typically dries up north ofKhartoum.

The Blue Nile (Amharic:ዓባይ,ʿĀbay^[42][43]) springs from Lake Tana in the Ethiopian Highlands. The Blue Nile flows about 1,400 kilometres to Khartoum, where the Blue Nile and White Nile join to form the Nile.^[44] Ninety percent of the water and ninety-six percent of the transported sediment carried by the Nile^[45] come from the Atbarah and Blue Nile,^{[1,922 out of 2,633 m3/s = 73%, so somewhere our numbers are off]} both of which originate in Ethiopia, with fifty-nine percent of the water coming from the Blue Nile. The erosion and transportation of silt only occurs during the Ethiopianrainy season when rainfall is especially high in theEthiopian Highlands; the rest of the year, the great rivers draining Ethiopia into the Nile have a weaker flow. In harsh and arid seasons and droughts, the Blue Nile dries out completely.^[46]

The flow of the Blue Nile varies considerably over its yearly cycle and is the main contribution to the large natural variation of the Nile flow. During the dry season the natural discharge of the Blue Nile can be as low as 113 m³/s (4,000 cu ft/s), although upstream dams regulate the flow of the river. During the wet season, the peak flow of the Blue Nile often exceeds 5,663 m³/s (200,000 cu ft/s) in late August (a difference of a factor of 50).

Before the placement of dams on the river the yearly discharge varied by a factor of 15 at Aswan. Peak flows of over 8,212 m³/s (290,000 cu ft/s) occurred during late August and early September, and minimum flows of about 552 m³/s (19,500 cu ft/s) occurred during late April and early May.

TheBahr al Ghazal and theSobat River are the two most important tributaries of the White Nile in terms of discharge.

The Bahr al Ghazal's drainage basin is the largest of any of the Nile's sub-basins, measuring 520,000 square kilometers (200,000 sq mi) in size, but it contributes a relatively small amount of water, about 2 m³/s (71 cu ft/s) annually, because tremendous volumes of water are lost in the Sudd wetlands.

The Sobat River, which joins the Nile a short distance below Lake No, drains about half as much land, 225,000 km² (86,900 sq mi), but contributes 412 cubic meters per second (14,500 cu ft/s) annually to the Nile.^[47] When in flood the Sobat carries a large amount of sediment, adding greatly to the White Nile's color.^[48]

The Yellow Nile is a former tributary that connected theOuaddaï highlands of eastern Chad to the Nile River Valleyc. 8000 toc. 1000 BCE.[49] Its remains are known as theWadi Howar. The wadi passes throughGharb Darfur near the northern border with Chad and meets up with the Nile near the southern point of the Great Bend.

The Nile has been the lifeline of civilization in Egypt since theStone Age, with most of the population and all of the cities of Egypt developing along those parts of the Nile valley lying north of Aswan. However, the Nile used to run much more westerly through what is now Wadi Hamim and Wadi al Maqar in Libya and flow into theGulf of Sidra.^[50] As the sea level rose at the end of themost recent ice age, the stream which is now the northern Nilecaptured the ancestral Nile nearAsyut.^[51] This change in climate also led to the current extents of theSahara desert, around 3400 BCE.^[52]

TheGiza pyramid complex originally overlooked a branch of the Nile that no longer exists. This branch was highest during theAfrican Humid Period.^[53][54]

The existing Nile has five earlier phases:

• i) the Upper Miocenian Eonile, of about 6 million yearsBP;^[55][7]
• ii) the Upper Pliocenian Paleonile, commencing about 3.32 million years BP, and during thePleistocene;
• iii) The Nile phases, including the Proto-Nile, commencing about 600,000 years BP;
• iv) Pre-Nile;^[56]
• v) transitioning at about 400,000 years BP to the Neo-Nile.^[55][56]

Flowing north from the Ethiopian Highlands,satellite imagery was used to identify dry watercourses in the desert to the west of the Nile. A canyon, now filled by surface drift, represents theEonile that flowed during 23–5.3 million years before present. The Eonile transportedclastic sediments to the Mediterranean; several natural gas fields have been discovered within these sediments.

During the late-MioceneMessinian salinity crisis, when the Mediterranean Sea was aclosed basin and evaporated to the point of being empty or nearly so, the Nile cut its course down to the new base level until it was several hundred metres below world ocean level at Aswan and 2,400 m (7,900 ft) below Cairo.^[57][58] This created a very long and deep canyon which was filled with sediment after the Mediterranean was recreated.^[59] At some point the sediments raised the riverbed sufficiently for the river to overflow westward into a depression to createLake Moeris.

Lake Tanganyika drained northwards into the Nile until theVirunga Volcanoes blocked its course in Rwanda. The Nile was much longer at that time, with its furthest headwaters in northern Zambia. The currently existing Nile first flowed during the former parts of theWürm glaciation period.^[7]

Affad 23 is anarchaeological site located in alluvial deposits formed by an ancient channel of the Nile in theAffad region of southernDongola Reach, Sudan.^[60]

There are two theories about the age of the integrated Nile. One is that the integrated drainage of the Nile is of young age and that the Nile basin was formerly broken into series of separate basins, only the most northerly of which fed a river following the present course of the Nile in Egypt and Sudan. Rushdi Said postulates that Egypt supplied most of the waters of the Nile during the early part of its history.^[61]

The other theory is that the drainage from Ethiopia via rivers equivalent to the Blue Nile, the Atbara and the Takazze flowed to the Mediterranean via the Egyptian Nile since well back intoTertiary times.^[62]

Salama suggests that during thePaleogene andNeogene Periods (66 million to 2.588 million years ago) a series of separate closed continental basins each occupied one of the major parts of the Sudanese Rift System:Mellut rift,White Nile rift,Blue Nile rift,Atbara rift andSag El Naam rift.^[63]The Mellut Basin is nearly 12 kilometers (7.5 mi) deep at its central part. This rift is possibly still active, with reportedtectonic activity in its northern and southern boundaries. TheSudd swamp which forms the central part of the basin may still be subsiding. The White Nile Rift system, although shallower than theBahr el Arab rift, is about 9 kilometers (5.6 mi) deep. Geophysical exploration of the Blue Nile Rift System estimated the depth of the sediments to be 5–9 kilometers (3.1–5.6 mi). These basins were not interconnected until their subsidence ceased, and the rate of sediment deposition was enough to fill and connect them.

The Egyptian Nile connected to the Sudanese Nile, which captures the Ethiopian and Equatorial headwaters during the current stages of tectonic activity in the Eastern, Central and Sudanese Rift systems.^[64] The connection of the different Niles occurred during cyclic wet periods. The Atbarah overflowed its closed basin during the wet periods that occurred about 100,000 to 120,000 years ago. The Blue Nile connected to the main Nile during the 70,000–80,000 years B.P. wet period. The White Nile system in Bahr El Arab and White Nile Rifts remained a closed lake until the connection of the Victoria Nile to the main system some 12,500 years ago during theAfrican humid period.

The Greek historianHerodotus wrote that "Egypt was the gift of the Nile". An unending source of sustenance, it played a crucial role in the development of Egyptian civilization. Because the river overflowed its banks annually and deposited new layers of silt, the surrounding land was very fertile. TheAncient Egyptians cultivated and traded wheat,flax,papyrus and other crops around the Nile. Wheat was a crucial crop in the famine-plagued Middle East. This trading system secured Egypt's diplomatic relationships with other countries and contributed to economic stability. Far-reaching trade has been carried on along the Nile since ancient times.^{[citation needed]} A tune,Hymn to the Nile, was created and sung by the ancient Egyptian peoples about the flooding of the Nile River and all of the miracles it brought to Ancient Egyptian civilization.^[65]

Water buffalo were introduced from Asia, and theAssyrians introduced camels in the 7th century BCE. These animals were raised for meat and were domesticated and used for ploughing—or in the camels' case, carriage. Water was vital to both people and livestock. The Nile was also a convenient and efficient means of transportation for people and goods.

The Nile was also an important part of ancient Egyptian spiritual life.Hapi was the god of the annual floods, and both he and thepharaoh were thought to control the flooding. The Nile was considered to be a causeway from life to death and the afterlife. The east was thought of as a place of birth and growth, and the west was considered the place of death, as the godRa, the Sun, underwent birth, death, and resurrection each day as he crossed the sky. Thus, all tombs were west of the Nile, because the Egyptians believed that in order to enter the afterlife, they had to be buried on the side that symbolized death.^{[citation needed]}

As the Nile was such an important factor in Egyptian life, the ancient calendar was even based on the three cycles of the Nile. These seasons, each consisting of four months of thirty days each, were calledAkhet,Peret, andShemu. Akhet, which means inundation, was the time of the year when the Nile flooded, leaving several layers of fertile soil behind, aiding in agricultural growth.^[66] Peret was the growing season, and Shemu, the last season, was the harvest season when there were no rains.^[66]

To the ancient Greeks and Romans, the upper reaches of the White Nile remained largely unknown, as they failed to penetrate theSudd wetlands of South Sudan.Vitruvius thought that source of the Nile was in Mauritania, on the "other" (south) side of theAtlas Mountains.^[68] Various expeditions failed to determine the river's source.Agatharchides records that in the time ofPtolemy II Philadelphus, a military expedition had penetrated far enough along the course of the Blue Nile to determine that the summer floods were caused by heavy seasonal rainstorms in the Ethiopian Highlands, but no European of antiquity is known to have reached Lake Tana. TheTabula Rogeriana depicted the source as three lakes in 1154.

Europeans began to learn about the origins of the Nile in the 14th century when the Pope sent monks as emissaries to Mongolia who passed India, the Middle East and Africa, and described being told of the source of the Nile in Abyssinia (Ethiopia).^[69] Later in the 15th and 16th centuries, travelers to Ethiopia visited Lake Tana and the source of the Blue Nile in the mountains south of the lake. Supposedly, Paolo Trevisani (c. 1452–1483), a Venetian traveller in Ethiopia, wrote a journal of his travels to theorigin of the Nile that has since been lost.[70]^[71]James Bruce claimed to be the first European to have visited the headwaters.^[72]Modern writers give the credit to theJesuitPedro Páez. Páez's account of the source of the Nile^[73] is a long and vivid account of Ethiopia. It was published in full only in the early 20th century, but was featured in works of Páez's contemporaries, like Baltazar Téllez,^[74]Athanasius Kircher^[75] andJohann Michael Vansleb.^[76]

Europeans had been resident in Ethiopia since the late 15th century, and one of them may have visited the headwaters even earlier without leaving a written trace. The Portuguese João Bermudes published the first description of theTis Issat Falls in his 1565 memoirs, compared them to the Nile Falls alluded to inCicero'sDe Republica.^[77]Jerónimo Lobo describes the source of the Blue Nile, visiting shortly after Pedro Páez. Telles also uses his account.

The White Nile was even less understood. The ancients mistakenly believed that theNiger River represented the upper reaches of the White Nile. For example,Pliny the Elder writes that the Nile had its origins "in a mountain of lowerMauretania", flowed above ground for "many days" distance, then went underground, reappeared as a large lake in the territories of theMasaesyli, then sank again below the desert to flow underground "for a distance of 20 days' journey till it reaches the nearest Ethiopians."^[78]

Modern exploration of the Nile basin began with theconquest of the northern and central Sudan by theOttoman viceroy of Egypt,Muhammad Ali, and his sons from 1821 onward. As a result of this, the Blue Nile was known as far as its exit from the Ethiopian foothills and the White Nile as far as the mouth of the Sobat River. Three expeditions under a Turkish officer, Selim Bimbashi, were made between 1839 and 1842, and two got to the point about 30 kilometres (20 miles) beyond the present port ofJuba, where the country rises and rapids make navigation very difficult.

Lake Victoria was first sighted by Europeans in 1858 when British explorerJohn Hanning Speke reached its southern shore while traveling withRichard Francis Burton to explore central Africa and locate the great lakes. Believing he had found the source of the Nile on seeing this "vast expanse of open water" for the first time, Speke named the lake afterQueen Victoria. Burton, recovering from illness and resting further south on the shores ofLake Tanganyika, was outraged that Speke claimed to have proven his discovery to be the true source of the Nile when Burton regarded this as still unsettled. A quarrel ensued which sparked intense debate within the scientific community and interest by other explorers keen to either confirm or refute Speke's discovery. British explorer and missionaryDavid Livingstone pushed too far west and entered theCongo River system instead. It was ultimately Welsh-American explorerHenry Morton Stanley who confirmed Speke's discovery, circumnavigating Lake Victoria and reporting the great outflow atRipon Falls on the lake's northern shore.

The Nile has long been used to transport goods along its length. Winter winds blow south, up river, so ships could sail up river using sails and down river using the flow of the river. While most Egyptians still live in the Nile valley, the 1970 completion of the Aswan Dam ended the summer floods and their renewal of the fertile soil, fundamentally changing farming practices. The Nile supports much of the population living along its banks, enabling Egyptians to live in otherwise inhospitable regions of the Sahara. The river's flow is disturbed at several points by the Cataracts of the Nile which form an obstacle to navigation by boats. The Sudd also forms a formidable navigation obstacle and impedes water flow, to the extent that Sudan had once attempted to build theJonglei Canal to bypass the swamp.^[79][80]

Nile cities include Khartoum, Aswan,Luxor (Thebes), and theGiza – Cairoconurbation. The first cataract, the closest to the mouth of the river, is at Aswan, north of the Aswan Dam. This part of the river is a regular tourist route, with cruise ships and traditional wooden sailing boats known asfeluccas. Many cruise ships ply the route between Luxor and Aswan, stopping atEdfu andKom Ombo along the way. Security concerns have limited cruising on the northernmost portion for many years.

A computer simulation study to plan the economic development of the Nile was directed by H.A.W. Morrice and W.N. Allan, for the Ministry of Hydro-power of Sudan, during 1955–57^[81][82][83] Morrice was their hydrological adviser, and Allan his predecessor. The calculations were enabled by accurate monthly inflow data collected for 50 years. The underlying principle was the use of over-year storage, to conserve water from rainy years for use in dry years. Irrigation, navigation and other needs were considered. Each computer run postulated a set of reservoirs and operating equations for the release of water as a function of the month and the levels upstream. The behavior that would have resulted given the inflow data was modeled. Over 600 models were run. Recommendations were made to the Sudanese authorities. The calculations were run on anIBM 650 computer. Simulation studies to design water resources are discussed further in the article onhydrology transport models, which have been used since the 1980s to analyze water quality.

Despite the development of many reservoirs, drought during the 1980s led to widespread starvation in Ethiopia and Sudan, but Egypt was nourished by water impounded in Lake Nasser. Drought has proven to be a major cause of fatality in the Nile river basin. According to a report by theStrategic Foresight Group, droughts in the last century have affected around 170 million people and killed half a million people.^[84] From the 70 incidents of drought which took place between 1900 and 2012, 55 incidents took place in Ethiopia, Sudan, South Sudan, Kenya and Tanzania.^[84]

The Nile's water has affected the politics of East Africa and theHorn of Africa for many decades. The dispute between Egypt and Ethiopia over the $4.5 billionGrand Ethiopian Renaissance Dam has become a national preoccupation in both countries, stoking patriotism, deep-seated fears and even murmurs of war.^[85] Countries including Uganda, Sudan, Ethiopia and Kenya have complained about Egyptian domination of its water resources. TheNile Basin Initiative promotes a peaceful cooperation among those states.^[86][87]

Several attempts have been made to establish agreements between the countries sharing the Nile waters. On 14 May 2010 atEntebbe, Uganda, Ethiopia, Rwanda, and Tanzania signed a new agreement on sharing the Nile water even though this agreement raised strong opposition from Egypt and Sudan. Ideally, such international agreements should promote equitable and efficient usage of the Nile basin's water resources. Without a better understanding about the availability of the future water resources of the Nile, it is possible that conflicts could arise between these countries relying on the Nile for their water supply, economic and social developments.^[10]

In 1951, AmericanJohn Goddard together with two French explorers became the first to successfully navigate the entire Nile from its source in Burundi at the potential headsprings of the Kagera River in Burundi to its mouth on the Mediterranean Sea, a journey of approximately 6,800 km (4,200 mi). Their 9-month journey is described in the bookKayaks down the Nile.^[88]

The White Nile Expedition, led by South African nationalHendrik Coetzee, navigated the White Nile's entire length of approximately 3,700 kilometres (2,300 mi). The expedition began at the White Nile's beginning at Lake Victoria in Uganda, on 17 January 2004 and arrived at the Mediterranean in Rosetta, four and a half months later.^[89]

The Blue Nile Expedition, led by geologist Pasquale Scaturro and his partner, kayaker and documentary filmmaker Gordon Brown became the first known people to descend the entire Blue Nile, from Lake Tana in Ethiopia to the beaches of Alexandria on the Mediterranean. Their approximately 5,230-kilometre (3,250 mi) journey took 114 days, from 25 December 2003 to 28 April 2004. Though their expedition included others, Brown and Scaturro were the only ones to complete the entire journey.^[90] Although they descendedwhitewater manually, the team usedoutboard motors for much of their journey.

On 29 January 2005, Canadian Les Jickling and New Zealander Mark Tanner completed the first human-powered transit of Ethiopia's Blue Nile. Their journey of over 5,000 kilometres (3,100 mi) took five months. They recount that they paddled through two war zones, regions notorious for bandits, and were arrested at gunpoint.^[91]

The following bridges cross the Blue Nile and connect Khartoum to Khartoum North:

• Mac Nimir Bridge^[92][93]
• Blue Nile Road & Railway Bridge
• Burri Bridge^{[citation needed]}
• Elmansheya Bridge^[94]
• Soba Bridge

The following bridges cross the White Nile and connect Khartoum to Omdurman:

• White Nile Bridge
• Victory Bridge, also known asEl Fitihab Bridge

The following bridges cross from Omdurman: to Khartoum North:

• Hafaya Bridge

The following bridges cross to Tuti from Khartoum state's three cities

• Tuti Bridge^[93][95] (previously known as the Khartoum North-Tuti bridge)^[92]

Other bridges

• Shandi Bridge,Shendi
• Atbarah Bridge,Atbarah
• Merowe Dam,Merowe
• Merowe Bridge, Merowe
• Aswan Bridge,Aswan
• Luxor Bridge,Luxor
• Suhag Bridge,Suhag
• Assiut Bridge,Assiut
• Al Minya Bridge,Minya
• Al Marazeek Bridge,Helwan
• First Ring Road Bridge (Moneeb Crossing),Cairo
• Abbas Bridge, Cairo
• University Bridge, Cairo
• Qasr al-Nil Bridge, Cairo
• 6th October Bridge, Cairo
• Abu El Ela Bridge, Cairo (removed in 1998)
• New Abu El Ela Bridge, Cairo
• Imbaba Bridge, Cairo
• Rod Elfarag Bridge, Cairo
• Second Ring Road Bridge, Cairo
• Banha Bridge, Banha
• Samanoud Bridge, Samanoud
• Mansoura 2 Bridges,Mansoura
• Talkha Bridge, Talkha
• Shirbine high Bridge
• Shirbine Bridge
• Kafr Sad – Farscor Bridge
• International Coastal Road Bridge
• Damietta high Bridge,Damietta
• Damietta Bridge,Damietta
• Kafr El Zayat Bridges, Kafr El Zayat
• Zefta Bridge, Zefta

• Source of the Nile Bridge,Jinja, Uganda
• River Nile Railway Bridge,Jinja, Uganda
• Nalubaale Bridge,Jinja, Uganda (FormerlyOwen Falls Bridge)
• Karuma Bridge,Karuma, Uganda
• Pakwach Bridge, Uganda

Notes

References

Sources

• Garstin, William E.; Cana, Frank R. (1911)."Nile" . InChisholm, Hugh (ed.).Encyclopædia Britannica. Vol. 19 (11th ed.). Cambridge University Press. pp. 692–699.

• Grogan, Ewart S. (1905)."The Nile as I saw it" .The Empire and the century. London: John Murray. pp. 809–16.
• Jeal, Tim (2011).Explorers of the Nile: The Triumph and Tragedy of a Great Victorian Adventure.ISBN 978-0-300-14935-7
• Moorehead, Alan, "The White Nile" (Hamish Hamilton, 1960; revised and illustrated edition, 1971). Abridged illustrated edition, as The Story of the White Nile (Harper & Row, 1967)
• Moorehead, Alan, "The Blue Nile" (Hamish Hamilton, 1962; revised and illustrated edition, 1972). Abridged illustrated edition, as The Story of the Blue Nile (Harper & Row, 1966)
• Tvedt, Terje, ed.The River Nile in the Post-Colonial Age: Conflict and Cooperation Among the Nile Basin Countries (I.B. Tauris, 2010) 293 pages; studies of the river's finite resources as shared by multiple nations in the post-colonial era; includes research by scholars from Burundi, Congo, Egypt, Ethiopia, Kenya, Rwanda, Sudan, Tanzania, and Uganda.
• Tvedt, Terje, (2004) "The Nile: An Annotated Bibliography", London/New York,ISBN 978-1860648793

• A Struggle Over the Nile – slideshow byThe New York Times
• Thesis Analyzing Nile River Negotiations (archived 10 January 2016)
•   Geographic data related toNile atOpenStreetMap
• Old maps of the Nile, from the Eran Laor Cartographic Collection, TheNational Library of Israel