NILE RIVER
The River Nile in Egypt
Origin Africa
Mouth Mediterranean Sea
Basin countries Sudan, Burundi, Rwanda, DR Congo, Tanzania, Kenya, Uganda, Ethiopia, Egypt
Length 6,695 km (4,160 mi)
Source elevation 1,134 m (3,721 ft)
Avg. discharge 2,830 m?/s (99,956 ft?/s)
Basin area 3,400,000 km? (1,312,740 mi?)
The Nile (Arabic: translit: an-nil, Ancient Egyptian iteru) is a major north-flowing river in Africa, generally regarded as the longest river—though not the most voluminous—on Earth. The Nile has two major tributaries, the White Nile and Blue Nile, the latter being the source of most of the Nile's water and fertile soil, but the former being the longer of the two. The White Nile rises in the Great Lakes region of central Africa, with the most distant source in southern Rwanda 2°16?55.92?S, 29°19?52.32?E, and flows north from there through Tanzania, Lake Victoria, Uganda and southern Sudan, while the Blue Nile starts at Lake Tana in Ethiopia, flowing into Sudan from the southeast. The two rivers meet near the Sudanese capital Khartoum.
The northern section of the river flows almost entirely through desert, from Sudan into Egypt, a country whose civilization has depended on the river since ancient times. Most of the population of Egypt and all of its cities, with the exception of those near the coast, lie along those parts of the Nile valley north of Aswan; and nearly all the cultural and historical sites of Ancient Egypt are found along the banks of the river.
The Nile ends in a large delta that empties into the Mediterranean Sea.
ETYMOLOGY OF THE NILE
The word "Nile" (Arab. 'nil) comes from the Greek word Neilos, meaning river valley. The ancient Egyptians called the Nile iteru, meaning "big river",
TRIBUTARIES
East Africa, showing the course of the Nile River, with the "Blue" and "White" Niles marked in those coloursThe drainage basin of the Nile covers 3,254,555 km, about 10% of the area of Africa.
There are two great Tributaries of the Nile: the White Nile, beginning in equatorial East Africa, and the Blue Nile, beginning in Ethiopia. Both branches are on the western flanks of the East African Rift, the southern part of the Great Rift Valley. Another less important one is Atbara which flows only while there is rain in Ethiopia and dries very fast.
WHITE NILE
The source of the Nile is sometimes considered to be Lake Victoria, but the lake itself has feeder rivers of considerable size. The most distant stream emerges from Nyungwe Forest in Rwanda, via the Rukarara, Mwogo, Nyabarongo and Kagera rivers, before flowing into Lake Victoria in Tanzania near the town of Bukoba.
The Blue Nile Falls fed by Lake Tana near the city of Bahar Dar, Ethiopia forms the upstream of the Blue Nile. It is also known as Tis Issat Falls after the name of the nearby village.The Nile leaves Lake Victoria at Ripon Falls, near Jinja, Uganda, as the Victoria Nile. It flows for approximately 500 km (300 miles) farther, through Lake Kyoga, until it reaches Lake Albert. After leaving Lake Albert, the river is known as the Albert Nile. It then flows into Sudan, where it becomes known as the Bahr al Jabal ("River of the Mountain"). At the confluence of the Bahr al Jabal with the Bahr al Ghazal, itself 720 km (445 miles) long, the river becomes known as the Bahr al Abyad, or the White Nile, from the white-ish clay suspended in its waters. From there, the river flows to Khartoum.
BLUE NILE
The Blue Nile (Ge'ez ?iqur Abbay (Black Abay) to Ethiopians; Bahr al Azraq to Sudanese) springs from Lake Tana in the Ethiopian Highlands. The Blue Nile flows about 1,400 km (850 miles) to Khartoum, where the Blue Nile and White Nile join to form the "Nile proper". 90% of the water and 96% of the transported sediment carried by the Nile originates in Ethiopia, but this runoff happens only in summer, when the great rains fall on the Ethiopian Plateau; the rest of the year, the great rivers draining Ethiopia into the Nile (Sobat, Blue Nile, and Atbarah) flow weakly.
HYDROLOGY
The flow rate of the Albert Nile at Mongalla is almost constant throughout the year and averages 1048 cubic meters per second (36,980 cubic feet per second). After Mongalla, the Nile is known as the Bahr El Jebel which enters the enormous swamps of the Sud region of the Sudan. More than half of the Nile’s water is lost in this swamp to evaporation and transpiration. The average flow rate in the Bahr El Jebel at the tails of the swamps is about 510 m/s (18,000 ft/s). From here it soon meets with the Sobat River and forms the White Nile.
The average flow of the White Nile at Malakal is 924 m/s (32,600 ft/s), the peak flow is approximately 1218 m/s (42,980 ft/s) in early March and minimum flow is about 609 m/s (21,490 ft/s) in late August. The fluctuation there is due the substantial variation in the flow of the Sobat which has a minimum flow of about 99 m?/s (3,490 ft/s) in August and a peak flow of over 680 m/s (24,000 ft/s) in early March.
From here the White Nile flows to Khartoum where it merges with the Blue Nile to form the Nile River. Further upstream the Atbara River, the last significant Nile tributary, merges with the Nile.
The White Nile contributes approximately 31% of the yearly Nile discharge. However during the dry season (January to June) the White Nile contributes between 70% and 90% of the total discharge from the Nile. During this period of time the natural discharge of the Blue Nile can be as low as 113 m?/s (3,990 ft/s), although upstream dams regulate the flow of the river. During the dry period, there will typically be no flow from the Atbara River.
The Blue Nile contributes approximately 80-90% of the Nile River discharge. 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 wet season the peak flow of the Blue Nile will often exceed 5663 m?/s (199,800 ft?/s) in latter August (variation by 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 8212 m/s (289,800 ft/s) would occur during the later portions of August and early September and minimum flows of about 552 m/s (19,500 ft/s) would occur during later April and early May.
The Nile basin is complex and because of this the discharge at any given point along the river depends on many factors including weather, diversions, evaporation/evapotranspiration, and ground water flow.
In 1958 radioisotope tracking led to the discovery of a subterranean river, also called a crypto-river, which flows beneath the Nile. The flow of this river is very large; estimates place the annual discharge in the range of 566 km? (135 mi). This is equivalent to an average flow rate of almost 18,000 m/s (635,000 ft/s). The discharge of this crypto-river is approximately six times the annual discharge of the Nile.
DISTRIBUTARIES OR BRANCHES
After the Blue and White Niles merge, the only remaining major tributary is the Atbara River, which originates in Ethiopia north of Lake Tana, and is approximately 800 km (500 miles) long. It joins the Nile approximately 300 km (200 miles) past Khartoum. The Nile is also unusual in that its last tributary (the Atbara) joins it approximately halfway to the sea. From that point north, the Nile diminishes because of evaporation.
The Nile in Sudan is distinctive for two reasons: 1) it flows over 6 groups of cataracts, from the first at Aswan to the sixth at Sabaloka (just north of Khartoum); and 2) it reverses direction for much of its course, flowing back toward the southwest before returning to flow north again to the sea. This is called the `"Great Bend of the Nile."'
The Nile splits into two branches (or distributaries), the Rosetta Branch to the west and the Damietta to the east, North of Cairo, forming the Nile Delta
HISTORY
The confluence of the Kagera and Ruvubu rivers near Rusumo Falls, part of the Nile's upper reaches.The Nile (iteru in Ancient Egyptian) was the lifeline of the ancient Egyptian civilization, with most of the population and all of the cities of Egypt resting along those parts of the Nile valley lying north of Aswan. The Nile has been the lifeline for Egyptian culture since the Stone Age. Climate change, or perhaps overgrazing, desiccated the pastoral lands of Egypt to form the Sahara desert, possibly as long ago as 8000 BC, and the inhabitants then presumably migrated to the river, where they developed a settled agricultural economy and a more centralized society.
Role in the founding of Egyptian civilization
Sustenance played a crucial role in the founding of Egyptian civilization. The Nile was an unending source of sustenance. The Nile made the land surrounding it extremely fertile when it flooded or was inundated annually. The Egyptians were able to cultivate wheat and crops around the Nile, providing food for the general population. Also, the Nile’s water attracted game such as water buffalo; and after the Persians introduced them in the 7th century BC, camels. These animals could be killed for meat, or could be captured, tamed and used for ploughing — or in the camels' case, traveling. Water was vital to both people and livestock. The Nile was also a convenient and efficient way of transportation for people and goods.
Egypt’s stability was one of the best structured in history. In fact, it might easily have surpassed many modern societies. This stability was an immediate result of the Nile’s fertility. The Nile also provided flax for trade. Wheat was also traded, a crucial crop in the Middle East where famine was very common. This trading system secured the diplomatic relationship Egypt had with other countries, and often contributed to Egypt's economic stability. Also, the Nile provided the resources such as food or money, to quickly and efficiently raise an army. Whether the army was to take on a defensive or offensive role is unknown.
The Nile played a major role in politics and social life. The Pharaoh would supposedly flood the Nile, and in return for the life-giving water and crops, the peasants would cultivate the fertile soil and send a portion of the resources they had reaped to the Pharaoh. He or she would in turn use it for the wellbeing of Egyptian society.
The Nile was a source of spiritual dimension. The Nile was so significant to the lifestyle of the Egyptians, that they created a god dedicated to the welfare of the Nile’s annual inundation. The god’s name was Hapi, and both he and the Pharaoh were thought to control the flooding of the Nile River. Also, the Nile was considered as a causeway from life to death and afterlife. The east was thought of as a place of birth and growth, and the west was considered the place of death, as the god Ra, the sun, underwent birth, death, and resurrection each time he crossed the sky. Thus, all tombs were located west of the Nile, because the Egyptians believed that in order to enter the afterlife, they must be buried on the side that symbolized death.
The Greek historian, Herodotus, wrote that ‘Egypt was the gift of the Nile’, and in a sense that is correct. Without the waters of the Nile River for irrigation, Egyptian civilization would probably have been short-lived. The Nile provided the elements that make a vigorous civilization, and contributed much to its lasting three thousand years.
That far-reaching trade has been carried on along the Nile since ancient times can be seen from the Ishango bone, possibly the earliest known indication of Ancient Egyptian multiplication, which was discovered along the headwaters of the Nile River (near Lake Edward, in northeastern Congo) and was carbon-dated to 20,000 BC.
THE SEARCH FOR THE SOURCE OF THE NILE
The Great Bend of the Nile in Sudan, looking north across the Sahara Desert towards Northern Sudan.Despite the attempts of the Greeks and Romans (who were unable to penetrate the Sudd), the upper reaches of the Nile remained largely unknown. Various expeditions had failed to determine the river's source, thus yielding classical Hellenistic and Roman representations of the river as a male god with his face and head obscured in drapery. Agatharcides records that in the time of Ptolemy 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 in Antiquity is known to have reached Lake Tana, let alone retraced the steps of this expedition farther than Meroe.
Europeans learned little new information about the origins of the Nile until the 15th and 16th centuries, when travelers to Ethiopia visited not only Lake Tana, but the source of the Blue Nile in the mountains south of the lake. Although James Bruce claimed to have been the first European to have visited the headwaters, and modern writers with better knowledge give the credit to the Jesuit Pedro Paez, Europeans had been resident in the country since the late 15th century, and it is entirely possible one of them had visited the headwaters but was unable to send a report of his discoveries out of Ethiopia.
The White Nile was even less understood, and the ancients mistakenly believed that the Niger River represented the upper reaches of the White Nile; for example, Pliny the Elder wrote that the Nile had its origins "in a mountain of lower Mauretania", flowed above ground for "many days" distance, then went underground, reappeared as a large lake in the territories of the Masaesyles, then sank again below the desert to flow underground "for a distance of 20 days' journey till it reaches the nearest Ethiopians" (N.H. 5.10). A merchant named Diogenes reported the Nile’s water attracted game such as water buffalo; and after the Persians introduced them in the 7th century BC, camels.
Lake Victoria was first sighted by Europeans in 1858 when the British explorer John Hanning Speke reached its southern shore whilst on his journey with Richard 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 after the then Queen of the United Kingdom. Burton, who had been recovering from illness at the time and resting further south on the shores of Lake Tanganyika, was outraged that Speke claimed to have proved his discovery to have been the true source of the Nile when Burton regarded this as still unsettled. A very public quarrel ensued, which not only sparked a great deal of intense debate within the scientific community of the day, but much interest by other explorers keen to either confirm or refute Speke's discovery. The well known British explorer and missionary David Livingstone failed in his attempt to verify Speke's discovery, instead pushing too far west and entering the Congo River system instead. It was ultimately the American explorer Henry Morton Stanley who confirmed the truth of Speke's discovery, circumnavigating Lake Victoria and reporting the great outflow at Rippon Falls on the Lake's northern shore. It was on this journey that Stanley was said to have greeted the British explorer with the famous words "Dr. Livingstone, I presume?" upon discovering the Scotsman ill and despondent in his camp on the shores of Lake Tanganyika.
The White Nile Expedition, led by South African national Hendri Coetzee, was to become the first to navigate the Nile in its entire length. The expedition took off from The Source of the Nile in Uganda on January 17, 2004 and arrived safely at the Mediterranean in Rosetta, 4 months and 2 weeks later. National Geographic released a feature film about the expedition towards in late 2005 entitled The Longest River.
On April 28, 2004, geologist Pasquale Scaturro and his partner, kayaker and documentary filmmaker Gordon Brown became the first people to navigate the Blue Nile, from Lake Tana in Ethiopia to the beaches of Alexandria on the Mediterranean. Though their expedition included a number of others, Brown and Scaturro were the only ones to remain on the expedition for the entire journey. They chronicled their adventure with an IMAX camera and two handheld video cams, sharing their story in the IMAX film "Mystery of the Nile," and in a book of the same title. Despite this attempt, the team was forced to use outboard motors for most of their journey, and it was not until January 29, 2005, when Canadian Les Jickling and New Zealander Mark Tanner reached the Mediterranean Sea, that the river had been paddled for the first time under human power.
On 30 April 2005, a team led by South Africans Peter Meredith and Hendri Coetzee became the first to navigate the most remote headstream, the true source of the Nile — the Akagera river which starts as the Rukarara in Nyungwe forest in Rwanda.
On March 31, 2006, three explorers from Britain and New Zealand claimed to have been the first to travel the river from its mouth to a new "true source" deep in Rwanda's Nyungwe rainforest. 2°16?55.92?S, 29°19?52.32?E. [2]
THE RIVER TODAY
The Eternal NileThe Nile still supports much of the population living along its banks, with the Egyptians living in otherwise inhospitable regions of the Sahara. The river flooded every summer, depositing fertile stilts on the plains. The flow of the river is disturbed at several points by cataracts, which are sections of faster-flowing water with many small islands, shallow water, and rocks, forming an obstacle to navigation by boats. The sudd in the Sudan also forms a formidable obstacle for navigation and flow of water, to the extent that Egypt had once attempted to dig a canal (the Jongeli Canal) to improve the flow of this stagnant mass of water (also known as Lake No).
The Nile was, and still is, used to transport goods to different places along its long path; especially since winter winds in this area blow up river, the ships could travel up with no work by using the sail, and down using the flow of the river. While most Egyptians still live in the Nile valley, the construction of the Aswan High Dam (finished in 1970) to provide hydroelectricity ended the summer floods and their renewal of the fertile soil.
Cities on the Nile include Khartoum, Aswan, Luxor (Thebes), and the Giza–Cairo conurbation. The first cataract, the closest to the mouth of the river, is at Aswan to the north of the Aswan Dams. The Nile north of Aswan is a regular tourist route, with cruise ships and traditional wooden sailing boats known as feluccas. In addition, many "floating hotel" cruise boats ply the route between Luxor and Aswan, stopping in at Edfu and Kom Ombo along the way. It used to be possible to sail on these boats all the way from Cairo to Aswan, but security concerns have shut down the northernmost portion for many years.
FLOODING OF THE NILE
The annual cycles of the Nile were very important to the lives of ancient Egyptians. Egypt’s stability was one of the best structured in history. In fact, it might easily have surpassed many modern societies. This stability was an immediate result of the Nile’s fertility. The Nile also provided flax for trade. Wheat was also traded, a crucial crop in the Middle East where famine was very common. This trading system secured the diplomatic relationship Egypt had with other countries, and often contributed to Egypt's economic stability. Also, the Nile provided the resources such as food or money, to quickly and efficiently raise an army, whether the army was to take on a defensive or offensive role.,
The Nile played a major role in politics and social life. The Pharaoh would supposedly flood the Nile, and in return for the life-giving water and crops, the peasants would cultivate the fertile soil and send a portion of the resources they had reaped to the Pharaoh. He or she would in turn use it for the wellbeing of Egyptian society.
More recently, drought during the 1980s led to widespread starvation in Ethiopia and Sudan but Egypt was protected from drought by water impounded in Lake Nasser. Beginning in the 1980s techniques of analysis using hydrology transport models have been used in the Nile to analyze water quality.
THE ECONILE
The present Nile is at least the fifth river that has flowed north from the Ethiopian Highlands. Satellite imagery was used to identify dry watercourses in the desert to the west of the Nile. An Eonile canyon, now filled by surface drift, represents an ancestral Nile called the Eonile that flowed during the later Miocene (23-5.3 million years before the present). The Eonile transported clastic sediments to the Mediterranean, where several gas fields have been discovered within these sediments. South of Cairo, the sand-filled canyon can reach a depth of up to 1400 meters.
During the late-Miocene Messinian Salinity Crisis, when the Mediterranean Sea was a closed basin and sealevel in the sea dropped approximately 1500 m, the Nile cut its course down to the new base level until it was several hundred feet below world ocean level at Aswan. This huge canyon is now full of later sediment.
Formerly, Lake Tanganyika drained northwards into the Nile, until the Virunga Volcanoes blocked its course in Rwanda. That would have made the Nile much longer, with its longest headwaters in northern Zambia.
Source: Wikipedia
LAKE NASSER
Coordinates 22°25?N 31°45?E
Lake type Reservoir
Primary sources Nile
Primary outflows Nile
Basin countries Egypt, Sudan
Max-length 550 km
Max-width 35 km
Surface area 5,250 km?
Average depth 25.2 m
Max-depth 130 m
Water volume 132? km[1]
Shore length1 7,844 m
Surface elevation
Lake Nasser (Arabic transliterated: Buhayrat Nasir) is a vast reservoir in southern Egypt and northern Sudan. Strictly, "Lake Nasser" refers only to the much larger portion of the lake that is in Egyptian territory (83% of the total), with the Sudanese preferring to call their smaller body of water Lake Nubia.
It was created as a result of the construction of the Aswan High Dam across the waters of the Nile between 1958 and 1970.
The lake is some 550 km long and 35 km across at its widest point, which is near the Tropic of Cancer. It covers a total surface area of 5,250 km? and has a storage capacity of some 157 km? of water.
The rising waters of the dam required major relocation projects that were carried out during the 1960s.
Several important Nubian archaeological sites were dismantled block by block and moved to higher ground, most notably Abu Simbel. The Sudanese river-port and railway terminal of Wadi Halfa was lost beneath the waters and a new town was built in its place; and Egypt's entire Nubian community from the upper reaches of the Nile – numbering several hundred thousand people – saw their villages disappear and were forced to relocate.
The Egyptian name is in honor of President Gamal Abdel Nasser, who was the mastermind behind the controversial High Dam project.
Rising lake levels through the 1990s resulted in spilling over of waters into the Western Desert, forming the Toshka Lakes beginning in 1998.
As the worlds largest man-made lake, Lake Nasser is approximately 310 miles in length (1550 square miles) and, in places, can reach a depth of 600 feet. The lake was created in the 1960s when the world famous High Dam was built. Together with the old Aswan Dam (built by the British between 1898 and 1902) it provides irrigation and electricity for the whole of Egypt. It is named for Gamal Abdel Nasser, president of Egypt from 1956-1970. The southern third of the lake is in Sudan and is called Lake Nubia. The lake is 312 miles (480 meters) long and covers an area of 2026 square miles (5,248 km2). It has a maximum depth of 426.5 ft (130 m) but its mean depth is 82.6 ft (25.2 m). The Egyptian portion is 202 miles (324 km) long and has a shoreline of 4,875 miles (7,844 km). Part of the area Lake Nasser covers today was once the site of the temples of Abu Simbel, built by Ramses II around 1200 B.C. The temple was moved but other sites of historical significance was submerged. Thirty-two species of fish, as well as Nile River crocodiles, are found in the lake. 80,000 tons of fish a year are caught.
The shoreline is a variety of desert landscapes, hilly and rugged, or flat and sandy with clean freshwater beaches.
The lake is remote and thinly populated by peasant fishermen, the local residents are Bedouin camel and sheep herdsmen who are occasionally seen grazing their flocks on the sparse vegetation at the edge of the lake.
There are an impressive variety of birds, mammals, and reptiles. More than 100 species of birds have been recorded: Wild duck, Egyptian geese, pelicans, herons, egrets and various species of hawks, kites, falcons and eagles will be among the birds seen. In most areas there are crocodile and monitor lizards, other types of wildlife include Dorcas gazelle, jackals, desert fox, and various smaller desert mammals.
Lake Nasser is a place where a small group of anglers have literally hundreds of square miles to themselves.
Lake Nasser has arguably the best freshwater fishing in the world for both Nile perch and Tiger Fish. There are also several species of catfish; the legendary giant Vundu being the biggest. Two species of Tilapia also inhabit the lake and give a good account of themselves on a fly rod. All told there are some thirty two species of fish in the lake.
ASWAN DAM
Aswan is a city on the first cataract of the Nile in Egypt. Two dams straddle the river at this point: the newer Aswan High Dam (Arabic: transliterated: as-Sad al-'Aly), and the older Aswan Dam or Aswan Low Dam.
Without impoundment the River Nile would flood each year during summer, as waters from East Africa flowed down the river. These floods brought nutrients and minerals that made the soil around the Nile fertile and ideal for farming. As the population along the river grew, there came a need to control the flood waters to protect farmland and cotton fields. In a high-water year, the whole crop may be entirely wiped out, while in a low-water year there was widespread drought and famine. The aim of this water project was to prevent the river's flooding, generate electricity and provide water for agriculture.
CONSTRUCTION HISTORY
The British began construction of the first dam in 1899 and it was completed in 1902. The project was designed by Sir William Willcocks and involved several eminent engineers including Sir Benjamin Baker and Sir John Aird, whose firm, John Aird & Company, was the main contractor. A gravity dam, it was 1,900 m long and 54 m high. The initial design was soon found to be inadequate and the height of the dam was raised in two phases, 1907–1912 and 1929–1933.
When the dam almost overflowed in 1946 it was decided that rather than raise the dam a third time, a second dam would be built 6 km upriver (about 4 miles). Proper planning began in 1952, just after the Nasser revolution, and at first the USA and Britain were to help finance construction with a loan of USD $70 million. Both nations cancelled the offer in July 1956 for reasons not entirely known. A secret Egyptian arms agreement with Czechoslovakia (Eastern Bloc) and Egyptian recognition of the People's Republic of China are cited as possible reasons. Soon thereafter, Nasser nationalized the Suez Canal, intending to use its tolls to subsidize the High Dam project. This prompted Britain, France, and Israel to attack Egypt, occupying the Suez Canal and precipitating the Suez Crisis. The United Nations, USSR and US forced the invaders to withdraw and the canal was left in Egyptian hands. The Egyptian government continued to intend to finance the dam project alone by using the revenues of the Suez Canal to help pay for construction. But as part of the Cold War struggle for influence in Africa the Soviet Union stepped in in 1958, and possibly a third of the cost of the dam was paid for as a gift. The Soviets also provided technicians and heavy machinery. The enormous rock and clay dam was designed by the Russian Zuk Hydroproject Institute.
Construction began in 1960. The High Dam, as-Sad al-'Aali, was completed on July 21, 1970, with the first stage finished in 1964. The reservoir began filling in 1964 while the dam was still under construction and first reached capacity in 1976. The reservoir raised concerns from archaeologists and a rescue operation was begun in 1960 under UNESCO. Sites were surveyed and excavated and 24 major monuments were moved to safer locations (see Abu Simbel) or granted to countries that helped with the works (such as the Debod temple in Madrid and the Temple of Dendur in New York).
BENEFITS
The Aswan High Dam is 3,600 m in length, 980 m wide at the base, 40 m wide at the crest and 111 m tall. It contains 43 million m? of material. At maximum, 11,000 m? of water can pass through the dam every second. There are further emergency spillways for an extra 5000 m? per second and the Toshka Canal links the reservoir to the Toshka Depression. The reservoir, named Lake Nasser, is 550 km long and 35 km at its widest with a surface area of 5,250 km? and holds 132 km?.
The dam powers twelve generators each rated at 175 megawatts, producing a hydroelectric output of 2.1 gigawatts. Power generation began in 1967. When the dam first reached peak output it produced around half of Egypt's entire electricity production (about 15% by 1998) and allowed for the connection of most Egyptian villages to electricity for the first time. The effects of dangerous floods in 1964 and 1973 and of threatening droughts in 1972–73 and 1983–84 were mitigated. A new fishing industry has been created around Lake Nasser, though it is struggling due to its distance from any significant markets.
ENVIRONMENTAL ISSURES
In addition to the benefits, however, damming the Nile caused a number of environmental issues. It flooded much of lower Nubia and over 90,000 people were displaced. Lake Nasser flooded valuable archeological sites. The silt which was deposited in the yearly floods, and made the Nile floodplain fertile, is now held behind the dam. Silt deposited in the reservoir is lowering the water storage capacity of Lake Nasser. Poor irrigation practices are waterlogging soils and bringing salt to the surface. Mediterranean fishing declined after the dam was finished because nutrients that used to flow down the Nile to the Mediterranean were trapped behind the dam.
There is some erosion of farmland down-river. Erosion of coastline barriers, due to lack of new sediments from floods, will eventually cause loss of the brackish water lake fishery that is currently the largest source of fish for Egypt, and the subsidence of the Nile Delta will lead to inundation of northern portion of the delta with seawater, in areas which are now used for rice crops. The delta itself, no longer renewed by Nile silt, has lost much of its fertility. The red-brick construction industry, which used delta mud, is also severely affected. There is significant erosion of coastlines (due to lack of sand, which was once brought by the Nile) all along the eastern Mediterranean.
The need to use artificial fertilizers supplied by international corporations is controversial too, causing chemical pollution which the traditional river silt did not. Indifferent irrigation control has also caused some farmland to be damaged by waterlogging and increased salinity, a problem complicated by the reduced flow of the river, which allows salt water to encroach further into the delta.
Mediterranean fish stocks are also negatively affected by the dam. The eastern basin of the Mediterranean is low in fertility, and traditionally the marine ecosystem depended on the rich flow of phosphate and silicates from the Nile outflow. Mediterranean catches decreased by almost half after the dam was constructed, but appear to be recovering. The dam has been implicated in a rise in cases of schistosomiasis (bilharzia), due to the thick plant life that has grown up in Lake Nasser, which hosts the snails who carry the disease.
The Aswan dam tends to increase the salinity of the Mediterranean Sea, and thus affects the Mediterranean's outflow current into the Atlantic ocean (see Strait of Gibraltar). This current can be traced thousands of kilometers into the Atlantic. Some people believe that the dam's effect on this outflow speeds up processes that lead to the next ice age.
Source: Wikipedia
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