Merowe Dam

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It may contain information of a speculative nature and the content may change dramatically as the construction of the dam approaches, and more information becomes available.

The Merowe High Dam, also known as Merowe Multi-Purpose Hydro Project or Hamdab Dam, is a large construction project in northern Sudan, about 350 km north of the capital Khartoum. It is situated on the river Nile, close to the 4th Cataract where the river divides into multiple smaller branches with large islands in between. Merowe is a city about 40 km downstream from the construction site at Hamdab. The main purpose of the dam will be the generation of electricity. Its dimensions make it the largest contemporary hydropower project in Africa.

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[edit] Technical details

The dam is designed to have a length of about 9km and a crest height of up to 67m. It will consist of concrete-faced rockfill dams on each river bank, an earth-rock dam with a clay core in the left river channel and a live water section in the right river channel (sluices, spillway and power intake dam with turbine housings). Once finished, it will contain a reservoir of 12.5 km³, or about 20% of the Nile's annual flow. The reservoir lake is planned to extend 174 km upstream. The powerhouse will be equipped with ten 125MW Francis turbines, each one designed for a nominal discharge rate of 300 m³/s, and each one driving a 150 MVA, 15 kV synchronous generator. The planners expect an annual electricity yield of 5.5 TWh, corresponding to an average load of 625 MW, or 50% of the rated load. To utilize the extra generation capacity, the Sudanese power grid will be upgraded and extended as part of the project. It is planned to build about 500 km of new 500 kV aerial transmission line across the Bayudah desert to Atbara, continuing to Omdurman/Khartoum, as well as about 1000 km of 220 kV lines eastwards to Port Sudan and westwards along the Nile, connecting to Merowe, Dabba and Dongola.

[edit] Planning and construction

The idea of a Nile dam at the 4th cataract is quite old. The authorities of the Anglo-Egyptian Sudan proposed it several times during the first half of the 20th century. It was supposed to equalize the large annual Nile flow fluctuations, create the possibility of growing cotton and provide flood protection for the lower Nile valley. After Sudan achieved independence in 1956, Egypt finally decided to control the Nile floods with a dam and reservoir on its own territory—the Aswan Dam and Nasser Lake.

The military government under President Nimeiri revived the plan in 1979, now with the intention of producing hydroelectricity for Sudan's rising demand. The following decade saw international industry and planning offices busy, producing a total of four feasibility studies [1 - Coyne et Bellier, 1979 / Gibb, Merz & McLellan, GB, 1983 / Sweco, SE, 1984 / Monenco Consultants Ltd., CA, 1989]. However, insufficient funding and lack of investor interest effectively stalled the project at the planning stage.

This appears to have changed fundamentally since the country started exporting oil in commercial quantities in the years 1999/2000. A greatly improved creditworthiness brought an influx of foreign investment, and the contracts for the construction of what is now known as the Merowe Dam project were signed in 2002 and 2003.

The main contractors are:

  • China International Water&Electric Corp., China National Water Resources and Hydropower Engineering Corp. (construction of dam, hydromechanical works)
  • Lahmeyer International (Germany - planning, project management, civil engineering)
  • Alstom (France - generators, turbines)
  • Harbin Power Engineering Company, Jilin Province Transmission and Substation Project Company (both China - transmission system extension)

By the time the contracts were signed, the Merowe Dam had been the largest international project the Chinese industry ever participated in.

River diversion and work on the concrete dams began in early 2004. The project timeline schedules the reservoir impounding to start in mid-2006 and the first generating unit to go on-line in mid-2007. The work will be finished when the water level in the reservoir will have reached 300 m above MSL and all ten generating units will be operational, scheduled for mid-2008.

[edit] Financing

The total project cost is reported to be EUR 1200 million. This can be subdivided into partial amounts for the construction work on the dam itself (ca. 45%), its technical equipment (ca. 25%) and the necessary upgrade of the power transmission system (ca. 30%). The project receives funding from

The remaining cost – approx. EUR 400 million – is supposed to be covered by the Sudanese government.

[edit] Benefits

The electrification level in Sudan is very low, even by the standards of the region. In 2002, the average Sudanese consumed 58 kWh of electricity per year [1], i.e., about one fifteenth of their Egyptian neighbors to the north, and less than one hundredth of the OECD average. The capital Khartoum and a few large plantations account for more than two thirds of the country's electric power demand, while most of the rural areas are not connected to the national grid. Many villages use the option of connecting small generators to the ubiquitous diesel-powered irrigation pumps. This way of generating electricity is rather inefficient and expensive.

The combined grid-connected generating capacity in Sudan was 728 MW in 2002, about 45% hydroelectricity and 55% oil-fired thermal plants. However, the effective capacity has always been a lot lower. The two main facilities, the Sennar (constructed in 1925) and Roseires (1966) dams on the Blue Nile, were originally designed for irrigation purposes rather than power production. Generating units were added during the 1960s and 1970s when the demand for electric power increased, but their power production is often heavily restricted by irrigation needs.

The government in Khartoum has announced plans to raise the country's electrification level from an estimated 30% to about 90% in the mid-term [2]. Large investments into the medium and low voltage distribution grids will be necessary but not sufficient to reach this ambitious goal: First and foremost, the foreseeable increase in power consumption would require the addition of generating capacity. During the 1990s, Sudanese electricity customers have already been plagued by frequent blackouts and brownouts due to insufficient generation. Three new thermal power plants went into operation in the Khartoum area in 2004, increasing the installed capacity to 1315 MW. The Merowe dam with its peak output of 1250 MW will almost double this capacity once it comes online.

[edit] Social impact

[edit] Resettlement

Before the construction began, an estimated 55,000 to 70,000 people were residents of the area which will be covered by the reservoir lake, mainly belonging to the Manasir, Hamadab and Amri tribes. They settle in small farming villages along the banks of the Nile and on the islands in the cataract. The whole region is relatively isolated, without paved roads or other infrastructure, and the communities are widely self-sufficient. Except for beans and millet the farmers grow vegetables, both for their own consumption and for trading at the weekly regional markets. However, their main source of income—and their most valuable possession—are the groves of date palms growing in the fertile silt on the river banks.

Once the dam is completed and the reservoir impounding begins, the whole population will be forced to move. While the majority of the farmers would prefer to stay as close to their old grounds as possible and build themselves a new existence at the shores of the new lake, the government has decided otherwise and pointed out three resettlement sites: Al-Multaqah, Al-Makabrab and Al-Muqadam. At these locations, farmers will receive plots of land relative in size to their former possessions, in addition to financial compensation for lost assets—houses and date palms.

Though government officials highlight the improved living conditions at the resettlement areas, with relatively modern buildings and infrastructure, the affected people reject the compensation plans. Their main objections are:

  • The soil at the resettlement areas is sandy and its quality is extremely poor, particularly if compared to the excellent farmland by the Nile. It would take much effort and a long time—probably decades—until it became fertile enough for growing vegetables and other marketable produce.
  • The government has announced that it will provide free water supply, sand removal and fertilizer during the first two years after the resettlement. After this period, the farmers will have to pay the full price for these services, none of which had to be used at the old site.
  • Compensation for a date palm amounts to about four years' harvest, while a good palm tree can bear fruit for a hundred years. Compensation for vegetable gardens is very low, and only married men will receive compensation for their houses.

About 6,000 people have been resettled to the Al-Multaqah site in the Nubian desert during 2003 and 2004. Their villages were the closest to the dam construction site near Hamdab. According to a survey conducted in early 2005 [3] the poverty rate has shot up dramatically since, because the farmers are not able to produce anything they could sell in the local markets.

[edit] Nomads

A significant fraction of the Manasir tribe inhabits the desert regions close to the Nile valley. The exact size of this nomadic population is unknown, but estimated to be of the same order of magnitude as that of the resident farmers, i.e., tens of thousands. Both groups maintain tight cultural interchanges and trade relations with each other.

Only the owners of real estate are covered under the compensation scheme. Nomadic families will not receive any compensation, even though the resettlement of the farming Manasir will deprive them of their symbiotic partners. The consequences for their ability to sustain their lives in a harsh environment remain to be assessed.

[edit] Archaeology

The fertile Nile valley has been attracting human settlement for thousands of years. The section between the 4th and 5th cataract—a significant portion of which will be inundated by the reservoir lake—has been densely populated through nearly all periods of (pre)history, but very little archaeological work has ever been conducted in this particular region. Recent surveys have confirmed the richness and diversity of traceable remains, from the Stone Age to the Islamic period.

Several foreign institutions have been recently or are currently involved in salvage archaeology in the region, among them the ACACIA project University of Cologne, [www.archeologia.pl] Gdańsk Archaeological Museum Expedition (GAME), Polish Academy of Sciences, Humboldt University of Berlin, the Italian Institute for Africa and the Orient (IsIAO), the University College London, the Sudan Archaeological Research Society, the Hungarian Meroe Foundationand the University of California at Santa Barbara

Their main problems are the shortness of the remaining time and limited funding. Unlike the large UNESCO campaign conducted in Egypt before the completion of the Aswan High Dam, when more than a thousand archaeological sites could be documented and complete buildings were moved to prevent them from drowning in Lake Nasser's floods, work at the 4th cararact is much more restricted.

[edit] Political impact

[edit] International

Usage rights to the waters of the Nile are fixed in the Nile Waters Treaty[4], negotiated by the British in 1959. It allots 82 percent of the water volume to Egypt, while Sudan is granted the rights to the remaining 18 percent. None of the riparian countries further upstream in the Nile basin—Ethiopia, Uganda, Rwanda, Burundi, Kenya and Tanzania—are entitled to any significant use of the water, be it for irrigation (of particular interest to Ethiopia and Kenya) or hydropower (Rwanda, Burundi, Uganda). As Sudan now pushes forward to make use of its water allotment, those countries have begun to call for a revision of the treaty, arguing that - with the exception of Ethiopia—they had all been under colonial rule at the time the negotiations took place, and had not been represented in their best interest. Moreover, the decision of distribution of water was made without any negotiations with Ethiopia, which had rejected the agreement and is the source of 90% of the water and 96% of transported sediment of the Nile.<ref>Marshall et al., Late Pleistocene and Holocene environmental and climatic change from Lake Tana, source of the Blue NilePDF (32KB), 2006</ref><ref>Daniel Kendie, The Five Dimensions of the Eritrean Conflict 1941 – 2004: Deciphering the Geo-Political Puzzle. United States of America: Signature Book Printing, Inc., 2005, pp.198.</ref>

[edit] Domestic

While a peace treaty seems to have stopped the fighting in Southern Sudan after almost 20 years, there is no end in sight yet for the civil war in the western Darfur province. In the worst case, the construction of the Merowe Dam could provoke the next armed conflict if a larger number of impoverished Nile farmers concluded that they had nothing left to lose.

[edit] Environmental impact

[edit] Sedimentation

[edit] Health

The resettlement area is a vast area with an expected 50,000–70,000 inhabitants who would be going through a transitional period for a few years before the get acclimatised & psychologically adapted to the new-life ahead. Governing by the two eminent health impact experiences of New Halfa resettlement projects and Aswan Dam in Egypt, strategic health planning ought to start early to foresee what water born diseases and other ecological health problems (such as bilharziasis, malaria) are likely to prevail and to plan how to guard against that.

[edit] Evaporation

The creation of the reservoir lake will increase the surface area of the Nile by about 700 km². Under the climatic conditions at the site, additional evaporation losses of up to 1,500,000,000 m³ per year can be expected. This corresponds to about 8% of the total amount of water allocated to Sudan in the Nile Waters Treaty.

[edit] External links


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