Large dams 2: Aswan High Dam

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ORT_Logo   Breadtag Sagas ©: Author Tony,  21 September 2015


Satellite image: Insightdigital & Google, Aswan High Dam 2009
Satellite image: Insightdigital & Google, Aswan High Dam 2009

Case study: The Aswan High Dam and the Nile in Egypt

Introduction

There are numerous case studies of dams and diversion projects around the world that illustrate issues and teach lessons. The disappearance of the Aral Sea in the Soviet Union is perhaps the most notorious. It is an extreme example of diversion irrigation in a desert to grow cotton: an awful lesson of where extreme ambition and unwillingness to face basic facts can lead to ecological and economic disaster.

Other case study dam projects are the Kariba in Zambia, the Tarbela in Pakistan, the Three Gorges Dam in China, dams on the Volga in Russia and the Colorado in the USA. However, for the purposes of this brief series on large dams, one case study the Aswan High Dam in Egypt is particularly pertinent and illustrates all of the issues involved.


The Aswan High Dam

Herodotus wrote that Egypt was an ‘acquired country’ the gift of the Nile. Over the past ten thousand years silt and water made a long ribbon of the Egyptian desert habitable and also built the Nile Delta (the richest agricultural part) gradually over the continental shelf. The prominence of Egypt in human history was due to its unique geography. Northeast winds allowed sailing upriver, while the Nile’s flow helped to waft craft downstream. More importantly the annual flood (prompted by monsoon rains in the Ethiopian highlands) brought water and 1 millimetre of silt on average to the river’s banks and floodplain. Sometimes the floods were too heavy bringing destruction and sometimes when the monsoon rains were too light a ‘low Nile’ could bring famine. Thus the gift had strings attached.

Improvements on the Nile gift came about 5000 years ago with irrigation canals, later supplemented by mechanical devices – water wheels and shadoofs (a lever arrangement with a bucket on a long pole).

One would expect that tampering with the bounty of the Nile gift, particularly the silt, would not be undertaken lightly. Nevertheless, attempts were made in the nineteenth and early twentieth century but these were relatively benign. It was only when in 1952 Colonel Gamal Abdul Nasser (1918-1970) and his fellow Free Officers seized power in Egypt, determined to rid the country of residual British influence and the shame of poverty and weakness, that the Aswan High Dam was born. The Aswan High Dam near the Egyptian border with Sudan was not as hydrologically sensible as dams higher up the Nile, but Nasser was rightly suspicious of schemes in other countries beyond his control. One consequence however was a location in one of the highest evaporation zones on earth (18% annually).

Photo: NASA from ISS, Lake Nasser, showing evaporation problem
Photo: NASA from ISS, Lake Nasser, showing evaporation problem

Nasser saw the Aswan High Dam as an heroic symbol for his revolutionary regime and for Arab nationalism. It would provide a reliable water supply for Egypt and enough hydroelectric power to transform the country into a modern industrial state.

It was the height of the ‘green revolution’ and consequently the dam did help to revolutionise Egyptian agriculture: providing flood control, permitting more systematic use of the water and allowing two to three crops a year. The Nile below Aswan became a mammoth irrigation ditch. The hydroelectricity supplied one third of Egypt’s needs between 1970 and 1990. In these respects, the dam fulfilled all of Nasser’s expectations, but it did not make Egypt prosperous and independent.

The dam markedly improved on one half of the Nile’s gift but it revoked the other. The Ethiopian soil subsidy stopped arriving in 1963 (98 per cent withheld by the dam). Without the silt Egypt became heavily reliant on chemical fertilisers (and pesticides), which made it one of the world’s heaviest users. Much of the electricity produced at Aswan went to fertiliser factories. And the country was sitting on a long-term time bomb. Ten thousand years of a working system squandered for nationalism, jingoism, but certainly modernisation.

Today, however, less than fifty years later, the Egyptians are in a policy double-bind. The dam is filling up with silt and they need the silt downstream, but they can’t do anything about it. The population has grown as a consequence of the modernisation of Egypt, and as Marq de Villiers says: ‘they cannot destroy the dam but neither can they tolerate it’. He also says: ‘this is not a view shared by the people who manage the dam or by many of the people who share its water.’ But, this form of denial is common everywhere.


Ecological consequences

‘There is no doubt where ecologists stand on the Aswan High dam,’ says Mark de Villiers. ‘In their view it is an unmitigated disaster.’ But also, remember the silt foregone and the sediment trapped. The dam is steadily silting up, and the evaporation problem is growing as the waters become shallower. Egypt increasingly needs more water than it gets, and the potential for conflict with the Sudan, Ethiopia and other countries, which also use the water, is growing. The possibility of catastrophe for Egypt is omnipresent.

Photo: Reddit Pics, Soviet & Egypt celebration of building of Aswan High Dam
Photo: Reddit Pics, Soviet & Egypt celebration of building of Aswan High Dam

Let’s forget the lurking Leviathan of the silt under the waters of Lake Nasser – the 600 kilometres long reservoir held back by the dam. The initial benefits of the dam were the control of the consequences of the costly Nile floods, provision of irrigation water throughout the year and generation of electricity. The downside, not immediately obvious in the midst of the ‘green revolution’, was that with the loss of the silt Egypt needed to use fertilisers and pesticides instead for its cash crops. As mentioned, it became one of the heaviest users of chemical fertilisers in the world and the fertiliser factories consumed a large proportion of the electricity generated.

Subsequent pollution by fertiliser nutrients and pesticides and the lack of scouring by floods created a water hyacinth weed problem that was costly to control and indirectly caused ongoing health problems in the population. The water hyacinth, irrigation ditches and stagnant water all made ideal habitats for the snails that form part of the lifecycle of the schistosome parasites that infect humans through the skin and cause Bilharzia, a particularly debilitating disease. Infection rates rose 5 to 10-fold among rural Egyptians with the transition to perennial irrigation, and after 1975 approached 100 per cent in many communities. (Other studies challenge this.)

The Nile descends only 87 metres from Aswan to the Mediterranean. The lack of flooding and constant irrigation raised the water table and caused drainage problems and waterlogging. Salt tends to be retained in the soil causing salinisation problems. This became so acute that Egypt hired international experts to find a remedy, but there was no financially practical solution. At the same time, the population had doubled since the dam was built, partly because of the ‘green revolution’ boon to agriculture. In a country with a million more mouths to feed each year in the 1990s, menaces to agriculture were serious matters.

In the delta, the lack of silt caused the delta to shrink slowly and to sink; salt invaded groundwater and seawater intruded as much as 50 kilometres. Marq de Villiers explains the situation in the words of Egyptologist Paul Theroux: ‘the delta is among the world’s most intensively cultivated lands, with one of the highest uses of fertilisers and the highest levels of soil salinity. It is sinking affecting groundwater. Egypt’s precious soil is being buried beneath Cairo’s relentless sprawl. The coast is eroding and chemical pesticides are killing marine life.’

Another result of the nutrient ooze from the silt no longer reaching the Mediterranean was destruction of the sardine and shrimp industries that had employed 30 000 Egyptians. The lack of the silt also had a further profound effect on the Mediterranean as a whole. John McNeill says that the most serious longterm consequence of the Aswan High Dam may be on the altered waters and biota of the Mediterranean (in conjunction with the effect of the Suez Canal). With saltier waters new species from the Red Sea have replaced many of the original species of marine life and this colonisation has spread as far as Sicily, impacting on all nations of the Eastern Mediterranean.

John McNeill also says that the dam swamped and corroded Egypt’s cultural heritage. Part of that heritage now lies under Lake Nasser, but irrigation, rising water tables and penetration of salt have also had a major impact on countless monuments downstream.

Photo: All Africa Com, GERD Dam Ethiopia 2015
Photo: All Africa Com, GERD Dam Ethiopia 2015

International issues are rising to the surface too. In 1959 a military coup in Khartoum helped Nasser to obtain the necessary water agreement with the Sudan. The new government was quite happy to punish the Nubians and the resettlement issue was not a problem for Egypt. The Khartoum Government, however, had to use the army to force some 50 000 Nubians to relocate whose towns and villages stood to sink beneath Lake Nubia (the Sudanese portion of the Reservoir). According to one author, twenty years later the Nubians still wanted their riverside homes and date palm groves back.

Water was plentiful when the dam was built, but with the growing population and shortages evident at the beginning of the new millennium, the agreement with the Sudan and the intentions of Ethiopia and Uganda are a growing worry and a potential source of conflict. Egypt has stated its willingness to go to war to prevent anyone upstream tampering with its water flow.

More recently the Ethiopian GERD dam under construction on the Blue Nile opens a welter of problems for Egypt to do with water flow and the amount of water available. The Blue Nile supplies the bulk of the water to Lake Nasser. Although international agreements have been negotiated between the three countries involved, lower riparian or downstream states always suffer. The presence of two large dams on the same river is likely to generate conflict at some stage.


Photo: A Davey, Flickr, Falls on the Blue Nile near Lake Tana 2007
Photo: A Davey, Flickr, Falls on the Blue Nile near Lake Tana 2007

Conclusion

Marq de Villiers elaborates on the general issues raised by the Aswan High Dam case study. He says: ‘Ironically, it has been reliably shown that malnutrition often follows dam building rather than the expected bounty from newly irrigated lands. Reasons are complex but stem partly from the failure of engineers to understand the ecological benefits of flooding.’

Egypt is an extreme case. One would have thought the benefits of the natural sequence of flood and silt here should have been ‘blindingly’ obvious. de Villiers says: Local people have developed flood dependent agriculture over centuries, the broad and reliable array of local foods is replaced by irrigated monoculture cash crops, often aimed at export markets. Thus introducing an economic version of floods and droughts, as world prices fluctuate.

Marq de Villiers also mentions that dams alter the flow and in warm climates the temperature of water downstream. They almost always lead to elevated salt levels in the surrounding soils, sometimes infecting groundwater. He mentions delta problems in other major rivers around the world, especially the feature that dams radically alter the nutrient and saline mix in downstream deltas.

In addition to the sardine industry in Egypt, he cites the effect on other fisheries which range from major declines – dams on the Niger dropped catches by a third, in south Florida by 40 per cent, in San Francisco Bay by four-fifths – to catastrophic ones in the USSR, Canada and the USA.

Dams filling with silt are also problems elsewhere. He mentions the Hoover Dam in the USA and an extreme case the Sanmexia Reservoir in China, which was completed in 1964 and taken out of commission four years later because of the build up of silt. Deforestation and poor agricultural practices dramatically increase erosion and siltation.

Dams also, by removing sediment, increase the flow rate of rivers and may also be the cause of flooding, making the floodplains downstream more, rather than less, susceptible to flooding in some cases.

Nor are dam collapses unknown and decommissioning of dams becomes a problem as dams age. For some reason decommissioning is never planned for when a dam is built. It is someone else’s problem (and cost)!


Comment

Someone will always argue the opposing case regarding the benefits of a particular dam; engineers like other closed professions are exceedingly resistant to criticism. Before the 1980s a critique of large dams was nearly impossible. Until the World Commission on Dams report in 2000, policy makers rarely paid much attention to these critiques.

Yet, as dams age and when insoluble problems accumulate and break into public awareness, then people will begin to say we should have done something sooner. Climate change is a similar example of the difficulties involved in persuading countries and governments to take action, even when it is in their best interests.

I won’t give details on the other case studies mentioned but as the Kariba Dam has been in the press frequently in the last twelve months and is a good example of the appalling treatment of those displaced by dams, I’ve include three links below. There are a couple of photographs of the Aral Sea and a video in Large Dams 1.

Key words: Aswan High Dam, case study, large dam, India’s Dam Shame, Polavaram Dam, World Commission on Dams, Aral Sea, Marq de Villiers, John McNeill


Further information

Marq de Villiers Water wars: Is the world’s water running out? Phoenix Press, London 2001.

John Mc Neill  Something new under the sun: an environmental history of the twentieth century Penguin, London 2001.

If you haven’t read Something new under the sun, John McNeill’s book is a brilliant, lucid, unimpassioned description of what changes humanity made in the twentieth century to the biosphere that were new and large.

‘To a degree unprecedented in human history, we have refashioned the earth’s air, water, and soil, and the biosphere of which we are a part. Based on exhaustive research, McNeill’s story—a compelling blend of anecdotes, data, and shrewd analysis—never preaches.’ (Google Book Reviews)

Tony: Protest Poster Polavaram Dam Project 2006
Tony: Protest Poster Polavaram Dam Project 2006

Aral Sea

See Large Dams 1: An introduction for photos and video on the Aral Sea

Kariba Dam

World Commission on Dams Report on Kariba Dam 2000

International Rivers Organisation brief comment on the displaced Tonga

The Daily Maverick an online South African newspaper provides an update on Kariba on 2 September 2015. The international press has similar articles on the same theme over the past twelve months.

GERD Dam Ethiopia

This is only the beginning of the impact of the GERD dam (Grand Ethiopian Renaissance Dam) on Egypt and Lake Nasser. Should Ethiopia not allow the dam to fill slowly Egypt will feel the negatives immediately that GERD is finished. Nevertheless, over years the potential for conflict between Ethiopia and Egypt will be high.

Wikipedia gives a background on the Grand Ethiopian Renaissance Dam (GERD)

BBC News 22 March 2014 gives a short description and some video footage on the GERD dam

MIT News USA,  22 April 2015 provides a map and a further description of GERD

Photos

A. Davey Flickr The falls of the Blue Nile Ethiopia. The falls are about 30km below Lake Tana.

Google satellite image of Aswan High Dam at insightdigital.org

Gerd photograph All Africa Com 3 April 2015

Other

Information from:

India’s Dam Shame: Why Polavaram Dam must not be built by Tony Stewart and Rukmini Rao, Gramya 2006.

Download: India’s Dam Shame

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