Aswan Dam
Encyclopedia
The Aswan Dam is an embankment dam
situated across the Nile
River in Aswan
, Egypt
. Since the 1950s, the name commonly refers to the High Dam, which is larger and newer than the Aswan Low Dam
, which was first completed in 1902. Construction of the High Dam became a key objective of the Egyptian Government following the Egyptian Revolution of 1952, as the ability to control the flood waters, and harness the hydroelectric power that it could produce, were seen as pivotal to Egypt's industrialisation. The High Dam was constructed between 1960 and 1970. It aimed to increase economic production by further regulating the annual river flood
ing and providing storage of water for agriculture
, and later, to generate hydroelectricity
. The dam has had a significant impact on the economy
and culture
of Egypt.
Before the dams were built, the Nile River flooded
each year during late summer, as water flowed down the valley from its East Africa
n drainage basin
. These floods brought high water and natural nutrient
s and mineral
s that annually enriched the fertile soil
along the floodplain
and delta
; this made the Nile valley ideal for farming since ancient times
. Because floods vary, in high-water years, the whole crop
might be wiped out, while in low-water years widespread drought
and famine
occasionally occurred. As Egypt's population grew and conditions changed, both a desire and ability developed to control the floods, and thus both protect and support farmland
and the economically important cotton
crop. With the reservoir
storage provided by these dams, the floods could be lessened, and the water could be stored for later release.
, to regulate the flooding of the Nile
, a task requiring an early attempt at an Aswan Dam. After his field work convinced him of the impracticality of this scheme, and fearing the Caliph's anger, he feigned madness
. He was kept under house arrest
from 1011 until al-Hakim's death in 1021, during which time he wrote his influential Book of Optics
.
. The project was designed by Sir William Willcocks
and involved several eminent engineers of the time, including Sir Benjamin Baker and Sir John Aird
, whose firm, John Aird & Co.
, was the main contractor.
, and the overthrow of the monarchy, led by the Free Officers Movement
, including its ultimate leader, Gamal Abdel Nasser
, as well as Anwar Sadat
.
Planning for the "High Dam" proper began in 1954, following the revolution, and changed development priorities. Initially, both the US and USSR were interested in the development of the dam, but this occurred in the increasingly tense readings of Cold War
happenings, as well as growing intra-Arab rivalries
.
In 1955 Nasser was trying to portray himself as the leader of Arab nationalism
, in opposition to the traditional monarchies, especially Hashemite
Iraq following its signing of the 1955 Baghdad Pact. At that time the US feared that communism would spread to the Middle East, and saw Nasser as a natural leader of an anti-communist Arab league. The US and Britain offered to help finance construction of the high dam with a loan of US$270 million in return for Nasser's leadership in resolving the Arab-Israeli conflict. While opposed both to communism and imperialism, Nasser presented himself as a tactical neutralist
, and sought to work with both the US and USSR for Egyptian and Arab benefit.
After a particularly criticized
raid by Israel against Egyptian forces in Gaza in 1955, Nasser realized that he could not legitimately portray himself as the leader of pan-Arab
nationalism if he could not defend his country militarily against Israel. In addition to his development plans, he looked to quickly modernize his military, and turned first to the US.
US Secretary of State John Foster Dulles
and US President Dwight Eisenhower told Nasser that the US would supply him with weapons only if they were used for defensive purposes and accompanied by US military personnel for supervision and training. Nasser did not accept these conditions and then looked to the Soviet Union for support. Although Dulles believed that Nasser was only bluffing, and that the USSR would not aid Nasser, he was wrong; the USSR promised Nasser a quantity of arms in exchange for a deferred payment of Egyptian grain and cotton. On 27 September 1955, Nasser announced an arms deal, with Czechoslovakia acting as a middleman for the Soviet support. Instead of retaliating against Nasser for turning to the Soviets, Dulles sought to improve relations with him. This explains the later offer of December 1955, in which the US and UK pledged $56 and $14 million respectively towards the construction of the dam.
Though the "Czech arms deal" actually increased US willingness to invest in Aswan, the British cited the deal as a reason for withdrawing their funding. What angered Dulles much more was Nasser’s recognition of communist China, which was in direct conflict with Dulles' policy of containment
. There are several other reasons why the US decided to withdraw the offer of funding. Dulles believed that the Soviet Union would not fulfill its commitment to help the Egyptians. He was also irritated by Nasser’s neutrality and attempts to play both sides of the Cold War. At the time, other western allies in the Middle East, including Turkey and Iraq, were irritated that Egypt, a persistently neutral country, was being offered so much aid.
In June 1956 the Soviets offered Nasser $1,120,000,000 at 2% interest for the construction of the dam. On 19 July the US State Department announced that it deemed American financial assistance for the High Dam "not feasible in present circumstances."
On 26 July 1956, with wide Egyptian acclaim, Nasser announced the nationalization of the Suez Canal
as well as fair compensation for the former owners. Nasser planned on the revenues generated by the canal helping to fund construction of the High Dam. When the Suez War broke out, the United Kingdom, France, and Israel were mainly successful in attaining their immediate military objectives, but pressure from the US and the USSR at the United Nations
and elsewhere forced them to withdraw.
In 1958 the Soviet Union
provided funding for the dam prodjekt.
In the 1950s archaeologists began raising concerns that several major historical sites were about to be under water. A rescue operation began in 1960 under UNESCO
. The Great Temple of Abu Simbel was preserved by relocating 22 monuments and architectural complexes to the shores of Lake Nasser under the UNESCO
Nubia Campaign. Other monuments were granted to countries that helped with the works (such as the Debod temple
in Madrid, the Temple of Taffeh
in Leiden and the Temple of Dendur
in New York). The remaining archeological sites have been flooded by Lake Nasser, among others the Buhen
fort.
On the Egyptian side, the project was led by Osman Ahmed Osman
's Arab Contractors
. The relatively young Osman underbid his only competitor by one-half.
, is 550 km long and 35 km at its widest with a surface area of 5,250 square kilometres. It holds 111 cubic kilometres of water.
The assessment of the costs and benefits of the dam remains a controversial issue decades after its completion. According to one estimate, the annual economic benefits of the High Dam right after its completion were Egyptian Pound (EP) 255 million (US$587m using the 1970 exchange rate of 2.3 US$ per EP): EP140 million from agricultural production, EP100 million from hydroelectric generation, EP10 million from flood protection, and EP5 million from improved navigation. At the time of its construction, total cost, including unspecified "subsidiary projects" and the extension of electric power lines, amounted to Egyptian EP450 million. Not taking into account the negative environmental and social impacts of the dam, its costs are thus estimated to have been recovered within only two years. One observer notes: "The impacts of the Aswan High Dam (...) have been overwhelmingly positive. Although the Dam has contributed to some environmental problems, these have proved to be significantly less severe than was generally expected, or currently believed by many people." Another observer disagrees and recommended that the dam should be torn down. Tearing it down would cost only a fraction of the funds required for "continually combating the dam's consequential damage" and 500,000 hectares of fertile land could be reclaimed from the layers of mud on the bed of the drained reservoir.
(840,000 hectares) from in the Delta and along the Nile Valley, increasing the country's irrigated area by a third. The increase was brought about both by irrigating what used to be desert and by bringing under cultivation of 385,000 ha that were previously used as flood retention basins. About half a million families were settled on these new lands. In particular the area under rice and sugar cane cultivation increased. In addition, about 1 million feddan (420,000 hectares), mostly in Upper Egypt, were converted from flood irrigation with only one crop per year to perennial irrigation allowing two or more crops per year. On other previously irrigated land, yields increased because water could be made available at critical low-flow periods. For example, wheat yields in Egypt tripled between 1952 and 1991 and better availability of water contributed to this increase. Most of the 32 km³ of freshwater, or almost 40% of the average flow of the Nile that were previously lost to the sea every year could be put to beneficial use. While about 10 km³ of the water saved is lost due to evaporation in Lake Nasser, the amount of water available for irrigation still increased by 22 km³.
Navigation and tourism. Navigation along the river has been improved, both upstream and downstream of the dam. Sailing along the Nile from Cairo to is a favorite tourism activity, which is mainly done during winter when the natural flow of the Nile would have been too low to allow navigation of cruise ships.
Fishing in Lake Nasser. A new fishing industry has been created around Lake Nasser, though it is struggling due to its distance from any significant markets. The annual production was
about 35 000 tons in the mid-90s. Factories for the fishing industry and packaging have been set up near the Lake.
The High Dam had a number of environmental and social impacts. Some but not all impacts were anticipated, and the impacts were mitigated to different degrees. Among the impacts that were anticipated were the resettlement of the Nubian population in the area inundated by the reservoir, the saving of historic monuments, the loss of soil fertility, health impacts and coastal erosion. Some anticipated impacts materialized only gradually and were mitigated only after a long delay and at great cost, such as waterlogging
and soil salinization. In the case of some other anticipated impacts, it is not clear if they have been mitigated or not, such as the impact on Mediterranean fisheries. Some anticipated impacts could simply not be mitigated, such as reservoir evaporation and sedimentation. Some anticipated impacts did not materialize, such as massive seepage from the reservoir, or were less severe than expected, such as river-bed erosion. There were also some impacts that were apparently not anticipated, such as the loss of arable land because the brick-making industry used alluvial deposits from existing lands instead of the annual sediment deposits.
and 100,000 to 120,000 people were resettled in Sudan and Egypt. The majority of the 50,000 Nubians resettled in Egypt were resettled three to ten kilometers from the Nile near Kom Ombo
45 kilometers downstream from Aswan in what was called " New Nubia". Housing and facilities were built for 47 village units whose relationship
to each other approximated that in Old Nubia. Irrigated land was provided to grow mainly sugar cane.
In Sudan 50,000 to 70,000 Sudanese Nubians were moved
approximately 700 kilometers south to the semi-arid Butana plain near the town of
Khashm el-Girba several hundred kilometers up the Atbara River. The climate there had a regular rainy season as opposed to their previous desert habitat in which virtually no rain fell. Unlike in Egypt, the host population included no Nubians. The government developed an irrigation
project, called the New Halfa Agricultural Development Scheme
to grow cotton, grains, sugar cane and other crops. The Nubians were resettled in twenty five planned villages that included schools, medical facilities and other services including piped water and some electrification.
s of various particle size - consisting of fine sand, silt
and clay
- on fields in Upper Egypt through its annual flood, contributing to soil fertiliy. However, the nutrient value of the sediment has often been overestimated. 88% of the sediment was carried to the sea before the construction of the High Dam. The nutrient value added to the land by the sediment was only 6,000 tons of potash
, 7,000 tons of phosphorus pentoxide
and 17,000 tons of nitrogen. These amounts are insignificant compared to what is needed to reach the yields achieved today in Egypt's irrigation. Also, the annual spread of sediment due to the Nile floods occurred along the banks of the Nile. Areas far from the river are now being irrigated which never received the Nile floods before.
. With the disappearance of the annual flood and heavy year-round irrigation, groundwater levels remained high with little fluctuation leading to waterlogging
. Soil salinity also increased because the distance between the surface and the groundwater table was small enough (1–2 m depending on soil conditions and temperature) to allow water to be pulled up by evaporation so that the relatively small concentrations of salt in the groundwater accumulated on the soil surface over the years. Since most of the farmland did not have proper subsurface drainage to lower the groundwater table, salinization gradually affected crop yields. A total of 2.1 million hectares thus required subsurface drainage at a cost that exceeded the construction cost of the High Dam. Only 20 years after completion of the High Dam the problem was seriously addressed and a large-scale drainage program was initiated.
, Philae
, Kalabsha and Amada
, which are important tourism attractions today.
Reservoir evaporation. Evaporation from Lake Nasser is estimated at 10 km3 per year, varying mainly as a function of the lake area. The absolute amount of water lost to evaporation is enormous. It is 11% of the average volume stored in the Lake and 18% of Egypt's share of the annual flow of the Nile.
Aquatic weeds. Before the construction of the High Dam, the 50,000 km of irrigation and drainage canals in Egypt had to be dredged regularly to remove sediments. After construction of the dam, aquatic weeds grew much faster in the clearer water, helped by fertilizer residues. The total length of the infested waterways was about 27,000 km in the mid-90s. Weeds have been gradually brought under control by manual, mechanical and biological methods.
Pollution from fertilizers. The increased use of artificial fertilizer
s in farmland below the dam has caused chemical pollution which the traditional river sediment did not do.
Fishery in the Delta and the Mediterranean. Mediterranean fishing and brackish water lake fishery declined after the dam was finished because nutrients that used to flow down the Nile to the Mediterranean were trapped behind the dam. For example, the Sardine
catch off the Egyptian coast declined from 18,000 tons in 1962 to a mere 460 tons in 1968, but then gradually recovered to 8,590 tons in 1992. A scientific article in the mid-1990s noted that " the mismatch between low primary productivity and relatively high levels of fish production in the region still presents a puzzle to scientist."
Impact on currents and salinity in the Mediterranean. The Aswan Dam tends to increase the salinity of the Mediterranean Sea, and this 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.
River-bed erosion. A concern before the construction of the High Dam had been the potential drop in river-bed level downstream of the Dam as the result of erosion caused by the flow of sediment-free water. Estimates by various national and international experts put this drop at between 2 and 10 metres. However, the actual drop has been measured at 0.3-0.7m, much less than anticipated.
Brick industry. The red-brick construction industry, which consisted of hundreds of factories that used Nile sediment deposits along the river, has also been negatively affected. Deprived of sediment, they started using the older alluvium of otherwise arable land taking out of production up to 120 square kilometers annually, with an estimated 1,000 square kilometers destroyed by 1984 when the government prohibited, “with only modest success,” further excavation. According to one source, bricks are now being made from new techniques which use a sand-clay mixture and it has been argued that the mud-based brick industry would have suffered even if the dam had not been built.
Algae growth. Because of the lower turbidity of the water sunlight penetrates deeper in the Nile water. Because of this and the increased presence of nutrients from fertilizers in the water, more algae grow in the Nile. This in turn increases the costs of drinking water treatment. Apparently few experts had anticipated that water quality in the Nile would actually decrease because of the High Dam.
Due to the absence of appreciable rainfall, Egypt's agriculture depends entirely on irrigation
. With irrigation, two crops per year can be produced, except for sugar cane which has a growing period of almost one year.
The high dam at Aswan releases, on average, 55 km³ water per year of which some 46 km³ are diverted into the irrigation canals.
In the Nile valley and delta, almost 33,600 square kilometres benefit from these waters producing on average 1.8 crops per year. The annual crop consumptive use of water is about 38 cubic kilometres. Hence, the overall irrigation efficiency is 38/46 = 0.82 or 82%. This is a relatively high irrigation efficiency. The field irrigation efficiencies are much less, but the losses are re-used downstream. This continuous re-use accounts for the high overall efficiency.
The following table shows that the equal distribution of irrigation water over the branch canals taking off from the main irrigation canals leaves much to be desired:
Salt balance
The salt concentration of the water in the Aswan reservoir is about 0.25 kg/m³, a very low salinity level. At an annual inflow of 55 km³, the annual salt import reaches 14 million tons. The average salt concentration of the drainage water evacuated into the sea and the coastal lakes is 2.7 kg/m³. At an annual discharge of 10 km³ (not counting the 2 km³ of salt intrusion from the sea and the lakes, see figure "Water balances"), the annual salt export reaches 27 million ton. In 1995, the salt export was higher than the import, and Egypt's agricultural lands were desalinizing
. Part of this could be due to the large number of subsurface drainage
projects executed in the last decades to control the water table
and soil salinity.
Drainage
Drainage
through sub-surface drains and drainage channels is essential to prevent a deterioration of crop yields from waterlogging
and soil salinization caused by irrigation. By 2003 more than 20000 square kilometres have been equipped with a subsurface drainage system
and approximately 7.2 km3 of water is drained annually from areas with these systems. The total investment cost in agricultural drainage over 27 years from 1973 to 2002 was about 3.1 billion US$ covering the cost of design, construction, maintenance, research and training. During this period 11 large scale projects were implemented with financial support from World Bank and other donors
Embankment dam
An embankment dam is a massive artificial water barrier. It is typically created by the emplacement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay and/or rock. It has a semi-permanent waterproof natural covering for its surface, and a dense, waterproof...
situated across the Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...
River in Aswan
Aswan
Aswan , formerly spelled Assuan, is a city in the south of Egypt, the capital of the Aswan Governorate.It stands on the east bank of the Nile at the first cataract and is a busy market and tourist centre...
, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
. Since the 1950s, the name commonly refers to the High Dam, which is larger and newer than the Aswan Low Dam
Aswan Low Dam
The Aswan Low Dam or Old Aswan Dam is a gravity masonry buttress dam on the Nile River in Aswan, Egypt. The dam was built at the former first cataract of the Nile, and is located about 1000 km up-river and 690 km south-southeast of Cairo...
, which was first completed in 1902. Construction of the High Dam became a key objective of the Egyptian Government following the Egyptian Revolution of 1952, as the ability to control the flood waters, and harness the hydroelectric power that it could produce, were seen as pivotal to Egypt's industrialisation. The High Dam was constructed between 1960 and 1970. It aimed to increase economic production by further regulating the annual river flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
ing and providing storage of water for agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, and later, to generate hydroelectricity
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
. The dam has had a significant impact on the economy
Economy of Egypt
The economy of Egypt was highly centralized under President Gamal Abdel Nasser. In the 1990s, a series of International Monetary Fund arrangements, coupled with massive external debt relief resulting from Egypt's participation in the Gulf War coalition, helped Egypt improve its macroeconomic...
and culture
Culture of Egypt
The culture of Egypt has thousands of years of recorded history. Ancient Egypt was among the earliest civilizations. For millennia, Egypt maintained a strikingly complex and stable culture that influenced later cultures of Europe, the Middle East and Africa. After the Pharaonic era, Egypt itself...
of Egypt.
Before the dams were built, the Nile River flooded
Flooding of the Nile
has been an important natal cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as Wafaa El-Nil. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, Esba`...
each year during late summer, as water flowed down the valley from its East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
n drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
. These floods brought high water and natural nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s and mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s that annually enriched the fertile soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
along the floodplain
Floodplain
A floodplain, or flood plain, is a flat or nearly flat land adjacent a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge...
and delta
Nile Delta
The Nile Delta is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Port Said in the east, it covers some 240 km of Mediterranean coastline—and is a rich...
; this made the Nile valley ideal for farming since ancient times
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...
. Because floods vary, in high-water years, the whole crop
Crop (agriculture)
A crop is a non-animal species or variety that is grown to be harvested as food, livestock fodder, fuel or for any other economic purpose. Major world crops include maize , wheat, rice, soybeans, hay, potatoes and cotton. While the term "crop" most commonly refers to plants, it can also include...
might be wiped out, while in low-water years widespread drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
and famine
Famine
A famine is a widespread scarcity of food, caused by several factors including crop failure, overpopulation, or government policies. This phenomenon is usually accompanied or followed by regional malnutrition, starvation, epidemic, and increased mortality. Every continent in the world has...
occasionally occurred. As Egypt's population grew and conditions changed, both a desire and ability developed to control the floods, and thus both protect and support farmland
Arable land
In geography and agriculture, arable land is land that can be used for growing crops. It includes all land under temporary crops , temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow...
and the economically important cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
crop. With the reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
storage provided by these dams, the floods could be lessened, and the water could be stored for later release.
Construction history
The earliest recorded attempt to build a dam near Aswan was in the 11th century, when the Arab polymath and engineer Ibn al-Haytham (known as Alhazen in the West) was summoned to Egypt by the Fatimid Caliph, Al-Hakim bi-Amr AllahAl-Hakim bi-Amr Allah
Abu ‘Ali Mansur Tāriqu l-Ḥākim, called Al-Hakim bi Amr al-Lāh , was the sixth Fatimid caliph and 16th Ismaili imam .- History :...
, to regulate the flooding of the Nile
Flooding of the Nile
has been an important natal cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as Wafaa El-Nil. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, Esba`...
, a task requiring an early attempt at an Aswan Dam. After his field work convinced him of the impracticality of this scheme, and fearing the Caliph's anger, he feigned madness
Feigned madness
Feigned madness a term used in popular culture to describe the assumption of a mental disorder for purposes of evasion or deceit, or to divert suspicion, perhaps in advance of an act of revenge.-To avoid responsibility:...
. He was kept under house arrest
House arrest
In justice and law, house arrest is a measure by which a person is confined by the authorities to his or her residence. Travel is usually restricted, if allowed at all...
from 1011 until al-Hakim's death in 1021, during which time he wrote his influential Book of Optics
Book of Optics
The Book of Optics ; ; Latin: De Aspectibus or Opticae Thesaurus: Alhazeni Arabis; Italian: Deli Aspecti) is a seven-volume treatise on optics and other fields of study composed by the medieval Muslim scholar Alhazen .-See also:* Science in medieval Islam...
.
Aswan Low Dam
Following their 1882 invasion and occupation of Egypt, the British began construction of the first dam across the Nile in 1898. Construction lasted until 1902, and it was opened on 10 December 1902, by HRH the Duke of Connaught and StrathearnDuke of Connaught and Strathearn
The title Duke of Connaught and Strathearn was granted by Queen Victoria of the United Kingdom of Great Britain and Ireland to her third son, Prince Arthur....
. The project was designed by Sir William Willcocks
William Willcocks
Sir William Willcocks KCMG was a British civil engineer. He is remembered as a renowned irrigation engineer, having proposed the first Aswan Dam and undertaken major projects of irrigation in South Africa and Turkey.A graduate of the Thomason College of Civil Engineering, Roorkee 1872 batch...
and involved several eminent engineers of the time, including Sir Benjamin Baker and Sir John Aird
John Aird (engineer)
Sir John Aird, 1st Baronet was a notable English civil engineering contractor of the late 19th and early 20th centuries. He is the Great Grandfather of Ollie Parkes...
, whose firm, John Aird & Co.
John Aird & Co.
John Aird & Co. was once a leading British civil engineering business based in London.-Early history:The company was founded in 1848 by John Aird with the objective of laying mains for gas and water companies in London....
, was the main contractor.
Aswan High Dam
After the Low Dam was almost over-topped in 1946, the British administration decided that rather than raise the dam a third time, a second dam should be built some 7 km upriver. The post-war years saw major changes in Egypt, including the growth of nationalism, the abrogation of the Anglo-Egyptian Treaty of 1936Anglo-Egyptian Treaty of 1936
The Anglo-Egyptian Treaty of 1936 was a treaty signed between the United Kingdom and the Kingdom of Egypt; it is officially known as The Treaty of Alliance Between His Majesty, in Respect of the United Kingdom, and His Majesty, the King of Egypt...
, and the overthrow of the monarchy, led by the Free Officers Movement
Free Officers Movement
In Egypt, the clandestine revolutionary Free Officers Movement was composed of young junior army officers committed to unseating the Egyptian monarchy and its British advisors...
, including its ultimate leader, Gamal Abdel Nasser
Gamal Abdel Nasser
Gamal Abdel Nasser Hussein was the second President of Egypt from 1956 until his death. A colonel in the Egyptian army, Nasser led the Egyptian Revolution of 1952 along with Muhammad Naguib, the first president, which overthrew the monarchy of Egypt and Sudan, and heralded a new period of...
, as well as Anwar Sadat
Anwar Sadat
Muhammad Anwar al-Sadat was the third President of Egypt, serving from 15 October 1970 until his assassination by fundamentalist army officers on 6 October 1981...
.
Planning for the "High Dam" proper began in 1954, following the revolution, and changed development priorities. Initially, both the US and USSR were interested in the development of the dam, but this occurred in the increasingly tense readings of Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
happenings, as well as growing intra-Arab rivalries
Arab Cold War
The Arab Cold War was a series of sub-conflicts, during the global Cold War period, waged between the Arab states from the era of European decolonization to the collapse of the Soviet Bloc. The term was coined by American political scientist and Middle East scholar Malcolm Kerr, in his 1965 book of...
.
In 1955 Nasser was trying to portray himself as the leader of Arab nationalism
Arab nationalism
Arab nationalism is a nationalist ideology celebrating the glories of Arab civilization, the language and literature of the Arabs, calling for rejuvenation and political union in the Arab world...
, in opposition to the traditional monarchies, especially Hashemite
Hashemite
Hashemite is the Latinate version of the , transliteration: Hāšimī, and traditionally refers to those belonging to the Banu Hashim, or "clan of Hashim", a clan within the larger Quraish tribe...
Iraq following its signing of the 1955 Baghdad Pact. At that time the US feared that communism would spread to the Middle East, and saw Nasser as a natural leader of an anti-communist Arab league. The US and Britain offered to help finance construction of the high dam with a loan of US$270 million in return for Nasser's leadership in resolving the Arab-Israeli conflict. While opposed both to communism and imperialism, Nasser presented himself as a tactical neutralist
Non-Aligned Movement
The Non-Aligned Movement is a group of states considering themselves not aligned formally with or against any major power bloc. As of 2011, the movement had 120 members and 17 observer countries...
, and sought to work with both the US and USSR for Egyptian and Arab benefit.
After a particularly criticized
United Nations Security Council Resolution 106
United Nations Security Council Resolution 106, adopted unanimously on March 29, 1955, after hearing reports from the Chief of Staff of the United Nations Truce Supervision Organization in Palestine and representatives of Egypt and Israel the Council noted that the Egyptian-Israel Mixed Armistice...
raid by Israel against Egyptian forces in Gaza in 1955, Nasser realized that he could not legitimately portray himself as the leader of pan-Arab
Pan-Arabism
Pan-Arabism is an ideology espousing the unification--or, sometimes, close cooperation and solidarity against perceived enemies of the Arabs--of the countries of the Arab world, from the Atlantic Ocean to the Arabian Sea. It is closely connected to Arab nationalism, which asserts that the Arabs...
nationalism if he could not defend his country militarily against Israel. In addition to his development plans, he looked to quickly modernize his military, and turned first to the US.
US Secretary of State John Foster Dulles
John Foster Dulles
John Foster Dulles served as U.S. Secretary of State under President Dwight D. Eisenhower from 1953 to 1959. He was a significant figure in the early Cold War era, advocating an aggressive stance against communism throughout the world...
and US President Dwight Eisenhower told Nasser that the US would supply him with weapons only if they were used for defensive purposes and accompanied by US military personnel for supervision and training. Nasser did not accept these conditions and then looked to the Soviet Union for support. Although Dulles believed that Nasser was only bluffing, and that the USSR would not aid Nasser, he was wrong; the USSR promised Nasser a quantity of arms in exchange for a deferred payment of Egyptian grain and cotton. On 27 September 1955, Nasser announced an arms deal, with Czechoslovakia acting as a middleman for the Soviet support. Instead of retaliating against Nasser for turning to the Soviets, Dulles sought to improve relations with him. This explains the later offer of December 1955, in which the US and UK pledged $56 and $14 million respectively towards the construction of the dam.
Though the "Czech arms deal" actually increased US willingness to invest in Aswan, the British cited the deal as a reason for withdrawing their funding. What angered Dulles much more was Nasser’s recognition of communist China, which was in direct conflict with Dulles' policy of containment
Containment
Containment was a United States policy using military, economic, and diplomatic strategies to stall the spread of communism, enhance America’s security and influence abroad, and prevent a "domino effect". A component of the Cold War, this policy was a response to a series of moves by the Soviet...
. There are several other reasons why the US decided to withdraw the offer of funding. Dulles believed that the Soviet Union would not fulfill its commitment to help the Egyptians. He was also irritated by Nasser’s neutrality and attempts to play both sides of the Cold War. At the time, other western allies in the Middle East, including Turkey and Iraq, were irritated that Egypt, a persistently neutral country, was being offered so much aid.
In June 1956 the Soviets offered Nasser $1,120,000,000 at 2% interest for the construction of the dam. On 19 July the US State Department announced that it deemed American financial assistance for the High Dam "not feasible in present circumstances."
On 26 July 1956, with wide Egyptian acclaim, Nasser announced the nationalization of the Suez Canal
Suez Crisis
The Suez Crisis, also referred to as the Tripartite Aggression, Suez War was an offensive war fought by France, the United Kingdom, and Israel against Egypt beginning on 29 October 1956. Less than a day after Israel invaded Egypt, Britain and France issued a joint ultimatum to Egypt and Israel,...
as well as fair compensation for the former owners. Nasser planned on the revenues generated by the canal helping to fund construction of the High Dam. When the Suez War broke out, the United Kingdom, France, and Israel were mainly successful in attaining their immediate military objectives, but pressure from the US and the USSR at the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
and elsewhere forced them to withdraw.
In 1958 the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
provided funding for the dam prodjekt.
In the 1950s archaeologists began raising concerns that several major historical sites were about to be under water. A rescue operation began in 1960 under UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
. The Great Temple of Abu Simbel was preserved by relocating 22 monuments and architectural complexes to the shores of Lake Nasser under the UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
Nubia Campaign. Other monuments were granted to countries that helped with the works (such as the Debod temple
Temple of Debod
The Templo de Debod or Temple of Debod is an ancient Egyptian temple which was rebuilt in Madrid, Spain.The temple was built originally 15 km south of Aswan in southern Egypt very close to the first cataract of the Nile and to the great religious center dedicated to the goddess Isis, in Philae...
in Madrid, the Temple of Taffeh
Temple of Taffeh
The Temple of Taffeh is an Ancient Egyptian temple which was presented to the Netherlands for its help in contributing to the historical preservation of Egyptian antiquities in the 1960's. The temple was built of sandstone between AD 1-14 on the orders of the Roman emperor Augustus. It was part of...
in Leiden and the Temple of Dendur
Temple of Dendur
The Temple of Dendur is a temple that was built by the Roman governor of Egypt, Petronius, around 15 BC and dedicated to Isis, Osiris, as well as two deified sons of a local Nubian chieftain, Pediese and Pihor...
in New York). The remaining archeological sites have been flooded by Lake Nasser, among others the Buhen
Buhen
Buhen was an ancient Egyptian settlement situated on the West bank of the Nile below the Second Cataract. It is well known for its fortress, probably constructed during the rule of Senusret III, around the year 1860 BC . The site may have been first established as an outpost in Nubia during the...
fort.
Construction and filling 1960-1976
The Soviets also provided technicians and heavy machinery. The enormous rock and clay dam was designed by the Soviet Hydroproject Institute along with some Egyptian engineers. 25 thousand Egyptian engineers and workers formed the backbone of the workforce required to complete this tremendous project which deeply changed many aspects in Egypt.On the Egyptian side, the project was led by Osman Ahmed Osman
Osman Ahmed Osman
Osman Ahmed Osman was a famous and influential Egyptian engineer, contractor, entrepreneur, and politician. Known commonly as el-mo'alim , Osman founded the Arab Contractors and led the Egyptian effort to build the Aswan Dam...
's Arab Contractors
Arab Contractors (company)
The Arab Contractors is an Egyptian construction and contracting company established in 1955 by Osman Ahmed Osman, an Egyptian entrepreneur and politician who served as Egypt's Housing Minister under Sadat's presidency. The company helped in constructing the Aswan Dam and helped during the 1973...
. The relatively young Osman underbid his only competitor by one-half.
- 1960: Start of construction on 9 January
- 1964: First dam construction stage completed, reservoir started filling
- 1970: The High Dam, as-Sad al-'Aali, completed on 21 July
- 1976: Reservoir reached capacity
- 2011: plans to build extension to dam
Specifications
The Aswan High Dam is 3,830 metres long, 980 metres wide at the base, 40 metres wide at the crest and 111 metres tall. It contains 43 million cubic metres of material. At maximum, 11,000 cubic metres per second of water can pass through the dam. There are further emergency spillways for an extra 5,000 cubic metres per second and the Toshka Canal links the reservoir to the Toshka Depression. The reservoir, named Lake NasserLake Nasser
Lake Nasser is a vast reservoir in southern Egypt, and northern Sudan, and is one of the largest man-made lakes in the world. Strictly, "Lake Nasser" refers only to the much larger portion of the lake that is in Egyptian territory , with the Sudanese preferring to call their smaller body of water...
, is 550 km long and 35 km at its widest with a surface area of 5,250 square kilometres. It holds 111 cubic kilometres of water.
Benefits
The main benefits of the High Dam are protection from floods and droughts, an increase in agricultural production and employment, electricity production and improved navigation that benefits tourism.The assessment of the costs and benefits of the dam remains a controversial issue decades after its completion. According to one estimate, the annual economic benefits of the High Dam right after its completion were Egyptian Pound (EP) 255 million (US$587m using the 1970 exchange rate of 2.3 US$ per EP): EP140 million from agricultural production, EP100 million from hydroelectric generation, EP10 million from flood protection, and EP5 million from improved navigation. At the time of its construction, total cost, including unspecified "subsidiary projects" and the extension of electric power lines, amounted to Egyptian EP450 million. Not taking into account the negative environmental and social impacts of the dam, its costs are thus estimated to have been recovered within only two years. One observer notes: "The impacts of the Aswan High Dam (...) have been overwhelmingly positive. Although the Dam has contributed to some environmental problems, these have proved to be significantly less severe than was generally expected, or currently believed by many people." Another observer disagrees and recommended that the dam should be torn down. Tearing it down would cost only a fraction of the funds required for "continually combating the dam's consequential damage" and 500,000 hectares of fertile land could be reclaimed from the layers of mud on the bed of the drained reservoir.
Drought protection, agricultural production and employment
The dams also protected Egypt from the droughts in 1972-1973 and 1983-1987 that devastated East and West Africa. The High Dam allowed Egypt to reclaim about 2 million feddanFeddan
A feddan is a unit of area. It is used in Egypt, Sudan, and Syria. The feddan is not an SI unit and in Arabic, the word means 'a yoke of oxen': implying the area of ground that could be tilled by them in a certain time. In Egypt the feddan is the only non-metric unit which remained in use...
(840,000 hectares) from in the Delta and along the Nile Valley, increasing the country's irrigated area by a third. The increase was brought about both by irrigating what used to be desert and by bringing under cultivation of 385,000 ha that were previously used as flood retention basins. About half a million families were settled on these new lands. In particular the area under rice and sugar cane cultivation increased. In addition, about 1 million feddan (420,000 hectares), mostly in Upper Egypt, were converted from flood irrigation with only one crop per year to perennial irrigation allowing two or more crops per year. On other previously irrigated land, yields increased because water could be made available at critical low-flow periods. For example, wheat yields in Egypt tripled between 1952 and 1991 and better availability of water contributed to this increase. Most of the 32 km³ of freshwater, or almost 40% of the average flow of the Nile that were previously lost to the sea every year could be put to beneficial use. While about 10 km³ of the water saved is lost due to evaporation in Lake Nasser, the amount of water available for irrigation still increased by 22 km³.
Electricity production
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 most Egyptian villages to use electricity for the first time. The High Dam has also improved the efficiency and the extension of the Old Aswan Hydropower stations.Other benefits
Flood protection. Periodic floods and droughts have affected Egypt since ancient times. The dam mitigated the effects of floods, such as in 1964, 1973 and 1988.Navigation and tourism. Navigation along the river has been improved, both upstream and downstream of the dam. Sailing along the Nile from Cairo to is a favorite tourism activity, which is mainly done during winter when the natural flow of the Nile would have been too low to allow navigation of cruise ships.
Fishing in Lake Nasser. A new fishing industry has been created around Lake Nasser, though it is struggling due to its distance from any significant markets. The annual production was
about 35 000 tons in the mid-90s. Factories for the fishing industry and packaging have been set up near the Lake.
Environmental and social impact
Waterlogging (agriculture)
Waterlogging refers to the saturation of soil with water. Soil may be regarded as waterlogged when the water table of the groundwater is too high to conveniently permit an anticipated activity, like agriculture....
and soil salinization. In the case of some other anticipated impacts, it is not clear if they have been mitigated or not, such as the impact on Mediterranean fisheries. Some anticipated impacts could simply not be mitigated, such as reservoir evaporation and sedimentation. Some anticipated impacts did not materialize, such as massive seepage from the reservoir, or were less severe than expected, such as river-bed erosion. There were also some impacts that were apparently not anticipated, such as the loss of arable land because the brick-making industry used alluvial deposits from existing lands instead of the annual sediment deposits.
Resettlement
Lake Nasser flooded much of lower NubiaNubia
Nubia is a region along the Nile river, which is located in northern Sudan and southern Egypt.There were a number of small Nubian kingdoms throughout the Middle Ages, the last of which collapsed in 1504, when Nubia became divided between Egypt and the Sennar sultanate resulting in the Arabization...
and 100,000 to 120,000 people were resettled in Sudan and Egypt. The majority of the 50,000 Nubians resettled in Egypt were resettled three to ten kilometers from the Nile near Kom Ombo
Kom Ombo
Kom Ombo or Ombos or Latin: Ambo and Ombi – is an agricultural town in Egypt famous for the Temple of Kom Ombo...
45 kilometers downstream from Aswan in what was called " New Nubia". Housing and facilities were built for 47 village units whose relationship
to each other approximated that in Old Nubia. Irrigated land was provided to grow mainly sugar cane.
In Sudan 50,000 to 70,000 Sudanese Nubians were moved
approximately 700 kilometers south to the semi-arid Butana plain near the town of
Khashm el-Girba several hundred kilometers up the Atbara River. The climate there had a regular rainy season as opposed to their previous desert habitat in which virtually no rain fell. Unlike in Egypt, the host population included no Nubians. The government developed an irrigation
project, called the New Halfa Agricultural Development Scheme
New Halfa Scheme
The New Halfa Scheme in Sudan is a 164,000 feddan site constructed in 1964 to house 50,000 Nubians displaced from Wadi Halfa, a town situated on the Nile near the border with Egypt, which was drowned when Lake Nasser formed behind the Aswan Dam...
to grow cotton, grains, sugar cane and other crops. The Nubians were resettled in twenty five planned villages that included schools, medical facilities and other services including piped water and some electrification.
Loss of sediments and soil fertility
Before the construction of the High Dam the Nile deposited sedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
s of various particle size - consisting of fine sand, silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
and clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
- on fields in Upper Egypt through its annual flood, contributing to soil fertiliy. However, the nutrient value of the sediment has often been overestimated. 88% of the sediment was carried to the sea before the construction of the High Dam. The nutrient value added to the land by the sediment was only 6,000 tons of potash
Potash
Potash is the common name for various mined and manufactured salts that contain potassium in water-soluble form. In some rare cases, potash can be formed with traces of organic materials such as plant remains, and this was the major historical source for it before the industrial era...
, 7,000 tons of phosphorus pentoxide
Phosphorus pentoxide
Phosphorus pentoxide is a chemical compound with molecular formula P4O10 . This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant.-Structure:...
and 17,000 tons of nitrogen. These amounts are insignificant compared to what is needed to reach the yields achieved today in Egypt's irrigation. Also, the annual spread of sediment due to the Nile floods occurred along the banks of the Nile. Areas far from the river are now being irrigated which never received the Nile floods before.
Waterlogging and increase in soil salinity
Before the construction of the High Dam, groundwater levels in the Nile Valley fluctuated 8-9m per year with the water level of the Nile. During summer when evaporation was highest, the groundwater level was too deep to allow salts dissolved in the water to be pulled to the surface through capillary actionCapillary action
Capillary action, or capilarity, is the ability of a liquid to flow against gravity where liquid spontanously rise in a narrow space such as between the hair of a paint-brush, in a thin tube, or in porous material such as paper or in some non-porous material such as liquified carbon fiber, or in a...
. With the disappearance of the annual flood and heavy year-round irrigation, groundwater levels remained high with little fluctuation leading to waterlogging
Waterlogging
Waterlogging or water logging may refer to:* Waterlogging , saturation of the soil by groundwater sufficient to prevent or hinder agriculture...
. Soil salinity also increased because the distance between the surface and the groundwater table was small enough (1–2 m depending on soil conditions and temperature) to allow water to be pulled up by evaporation so that the relatively small concentrations of salt in the groundwater accumulated on the soil surface over the years. Since most of the farmland did not have proper subsurface drainage to lower the groundwater table, salinization gradually affected crop yields. A total of 2.1 million hectares thus required subsurface drainage at a cost that exceeded the construction cost of the High Dam. Only 20 years after completion of the High Dam the problem was seriously addressed and a large-scale drainage program was initiated.
Coastal erosion
The High Dam has accelerated erosion of coastlines (due to lack of sediment, which was once brought by the Nile) in Egypt and, according to some sources even all along the eastern Mediterranean. Coastal erosion occurred and efforts to control it were made even before the construction of the High Dam. This erosion may to some extent have been caused by the limited trapping of sediments behind the Old Aswan Dam. The High Dam accelerated erosion and made the construction of further expensive coastal protection works in the Nile Delta necessary.Health impact
The standing water in irrigation canals is a breeding ground for snails carrying the parasite bilharzia. The incidence of bilharzia increased due to the Aswan High Dam inhibiting the natural fluctuations in water height. Important factors contributing to the prevalence of schistosomiasis were poor sanitation and limited awareness of how the disease was transmitted. Provision of clean water, sanitation, health education and rural clinics has reduced the overall prevalences of schistosomiasis from more than 40 per cent during the pre-dam period to 10 per cent in 1995 and only 2% in 2002.Historical monuments
A number of historical monuments were located in the area that was flooded by Lake Nasser. UNESCO and the Egyptian authorities transferred many of them to higher ground, including Abu SimbelAbu Simbel
Abu Simbel temples refers to two massive rock temples in Abu Simbel in Nubia, southern Egypt on the western bank of Lake Nasser about 230 km southwest of Aswan...
, Philae
Philae
Philae is an island in the Nile River and the previous site of an Ancient Egyptian temple complex in southern Egypt...
, Kalabsha and Amada
Amada
The Temple of Amada, the oldest Egyptian temple in Nubia, was first constructed by pharaoh Thutmose III of the 18th dynasty and dedicated to Amun and Re-Horakhty. His son and successor, Amenhotep II continued the decoration program for this structure. Amenhotep II's successor, Thutmose IV decided...
, which are important tourism attractions today.
Other impacts
Reservoir sedimentation. Sediment deposited in the reservoir is lowering the water storage capacity of Lake Nasser. The reservoir storage capacity is 162 km3, including 31 km3 dead storage at the bottom of the lake below 147m above sea level, 90 km3 live storage, and 41 km3 of storage for high flood waters above 175m above sea level. The annual sediment load of the Nile is about 134 million tons. This means that the dead storage volume would be filled up after 300–500 years if the sediment accumulated at the same rate throughout the area of the lake. Obviously sediment accumulates much faster at the upper reaches of the Lake where sedimentation has already affected the live storage zone. It would take about another 900 years until the live storage zone would be completely sedimented and operation of the dam would become impossible some time before that.Reservoir evaporation. Evaporation from Lake Nasser is estimated at 10 km3 per year, varying mainly as a function of the lake area. The absolute amount of water lost to evaporation is enormous. It is 11% of the average volume stored in the Lake and 18% of Egypt's share of the annual flow of the Nile.
Aquatic weeds. Before the construction of the High Dam, the 50,000 km of irrigation and drainage canals in Egypt had to be dredged regularly to remove sediments. After construction of the dam, aquatic weeds grew much faster in the clearer water, helped by fertilizer residues. The total length of the infested waterways was about 27,000 km in the mid-90s. Weeds have been gradually brought under control by manual, mechanical and biological methods.
Pollution from fertilizers. The increased use of artificial fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s in farmland below the dam has caused chemical pollution which the traditional river sediment did not do.
Fishery in the Delta and the Mediterranean. Mediterranean fishing and brackish water lake fishery declined after the dam was finished because nutrients that used to flow down the Nile to the Mediterranean were trapped behind the dam. For example, the Sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
catch off the Egyptian coast declined from 18,000 tons in 1962 to a mere 460 tons in 1968, but then gradually recovered to 8,590 tons in 1992. A scientific article in the mid-1990s noted that " the mismatch between low primary productivity and relatively high levels of fish production in the region still presents a puzzle to scientist."
Impact on currents and salinity in the Mediterranean. The Aswan Dam tends to increase the salinity of the Mediterranean Sea, and this affects the Mediterranean's outflow current into the Atlantic Ocean (see Strait of Gibraltar
Strait of Gibraltar
The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Spain in Europe from Morocco in Africa. The name comes from Gibraltar, which in turn originates from the Arabic Jebel Tariq , albeit the Arab name for the Strait is Bab el-Zakat or...
). This current can be traced thousands of kilometers into the Atlantic.
River-bed erosion. A concern before the construction of the High Dam had been the potential drop in river-bed level downstream of the Dam as the result of erosion caused by the flow of sediment-free water. Estimates by various national and international experts put this drop at between 2 and 10 metres. However, the actual drop has been measured at 0.3-0.7m, much less than anticipated.
Brick industry. The red-brick construction industry, which consisted of hundreds of factories that used Nile sediment deposits along the river, has also been negatively affected. Deprived of sediment, they started using the older alluvium of otherwise arable land taking out of production up to 120 square kilometers annually, with an estimated 1,000 square kilometers destroyed by 1984 when the government prohibited, “with only modest success,” further excavation. According to one source, bricks are now being made from new techniques which use a sand-clay mixture and it has been argued that the mud-based brick industry would have suffered even if the dam had not been built.
Algae growth. Because of the lower turbidity of the water sunlight penetrates deeper in the Nile water. Because of this and the increased presence of nutrients from fertilizers in the water, more algae grow in the Nile. This in turn increases the costs of drinking water treatment. Apparently few experts had anticipated that water quality in the Nile would actually decrease because of the High Dam.
Irrigation for agriculture
Surface irrigation
Surface irrigation is defined as the group of application techniques where water is applied and distributed over the soil surface by gravity. It is by far the most common form of irrigation throughout the world and has been practiced in many areas virtually unchanged for thousands of years.Surface...
. With irrigation, two crops per year can be produced, except for sugar cane which has a growing period of almost one year.
The high dam at Aswan releases, on average, 55 km³ water per year of which some 46 km³ are diverted into the irrigation canals.
In the Nile valley and delta, almost 33,600 square kilometres benefit from these waters producing on average 1.8 crops per year. The annual crop consumptive use of water is about 38 cubic kilometres. Hence, the overall irrigation efficiency is 38/46 = 0.82 or 82%. This is a relatively high irrigation efficiency. The field irrigation efficiencies are much less, but the losses are re-used downstream. This continuous re-use accounts for the high overall efficiency.
The following table shows that the equal distribution of irrigation water over the branch canals taking off from the main irrigation canals leaves much to be desired:
| Branch canal | Water delivery in m³/feddan *) |
|---|---|
| Kafret Nasser | 4700 |
| Beni Magdul | 3500 |
| El Mansuria | 3300 |
| El Hammami upstream | 2800 |
| El Hammami downstream | 1800 |
| El Shimi | 1200 |
*) Period 1 March to 31 July. 1 feddanFeddanA feddan is a unit of area. It is used in Egypt, Sudan, and Syria. The feddan is not an SI unit and in Arabic, the word means 'a yoke of oxen': implying the area of ground that could be tilled by them in a certain time. In Egypt the feddan is the only non-metric unit which remained in use...
is about 1 acre or 0.42 ha.*) Data from the Egyptian Water Use Management Project (EWUP)
Salt balance
The salt concentration of the water in the Aswan reservoir is about 0.25 kg/m³, a very low salinity level. At an annual inflow of 55 km³, the annual salt import reaches 14 million tons. The average salt concentration of the drainage water evacuated into the sea and the coastal lakes is 2.7 kg/m³. At an annual discharge of 10 km³ (not counting the 2 km³ of salt intrusion from the sea and the lakes, see figure "Water balances"), the annual salt export reaches 27 million ton. In 1995, the salt export was higher than the import, and Egypt's agricultural lands were desalinizing
Leaching (agriculture)
In agriculture, leaching refers to the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss.Leaching may also refer to ...
. Part of this could be due to the large number of subsurface drainage
Drainage system (Agriculture)
An agricultural drainage system is a system by which the water level on or in the soil is controlled to enhance agricultural crop production.-Classification:Figure 1 classifies the various types of drainage systems...
projects executed in the last decades to control the water table
Watertable control
Watertable control is the practice of controlling the water table in agricultural land by subsurface drainage with proper criteria to improve the crop production.- Description and definitions :...
and soil salinity.
Drainage
Drainage
Drainage
Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...
through sub-surface drains and drainage channels is essential to prevent a deterioration of crop yields from waterlogging
Waterlogging
Waterlogging or water logging may refer to:* Waterlogging , saturation of the soil by groundwater sufficient to prevent or hinder agriculture...
and soil salinization caused by irrigation. By 2003 more than 20000 square kilometres have been equipped with a subsurface drainage system
Drainage system (Agriculture)
An agricultural drainage system is a system by which the water level on or in the soil is controlled to enhance agricultural crop production.-Classification:Figure 1 classifies the various types of drainage systems...
and approximately 7.2 km3 of water is drained annually from areas with these systems. The total investment cost in agricultural drainage over 27 years from 1973 to 2002 was about 3.1 billion US$ covering the cost of design, construction, maintenance, research and training. During this period 11 large scale projects were implemented with financial support from World Bank and other donors
See also
- Egyptian Public WorksEgyptian Public WorksThe Egyptian Department of Public Works was established in the early Nineteenth Century, and concentrates mainly on public works relating to irrigation and hydraulic engineering. These irrigation projects have constituted the bulk of work performed by this entity in Egypt...
- List of conventional hydroelectric power stations
- List of largest dams
- List of power stations in Egypt
- Water politics in the Nile Basin
- Water supply and sanitation in EgyptWater supply and sanitation in EgyptWater supply and sanitation in Egypt is characterized by both achievements and challenges. Among the achievements are an increase of piped water supply between 1990 and 2006 from 89% to 99% in urban areas and from 39% to 82% in rural areas despite rapid population growth; the elimination of open...
External links
- Sayed El-Sayed and Gert L. van Dijken 'The southeastern Mediterranean ecosystem revisited: Thirty years after the construction of the Aswan High Dam.'
- Aswan High Dam
- Old Aswan Dam
- The Nile Under Control - An article from 1937 about controlling the flow of the Nile.
- Info on the Aswan Dam
- View the official opening of the Aswan Dam in 1971