Introduction

The heightening of the Roseris Dam is considered the second and final stage of the construction of the dam. The foundations of the dam were built to support a concrete dam to construct a reservoir that provides for 490 m of water level (above the sea level). In the first stage in 1966, the concrete dam was only built to provide for a water-level of 480 m. The heightening of the concrete dam by 10 m will increase the reservoir capacity from 3 Milliard cubic metres to 7 Milliard cubic metres.

Objective of the Project

1. Full utilisation of the Sudan share from the Nile Waters Agreement -1959.
2. Strategic storage to face the outbreak of drought periods that occur in the sub-Saharan Africa.

Benefits of the Project

1. Guarantee of the water demand for the irrigated schemes on the Blue Nile banks. This will stop the need to cut down the irrigated area in the drought years.
2. Supply of water for rehabilitation of the pump-irrigated schemes on the Blue Nile that allows the expansion of these schemes.
3. Supply of water for expanding projects like the Greater Kenanna and the second stage of Al-Rahad Scheme.
4. Increase the capacity of hydropower generation by about 45% of the current capacity.

Components of the Project

• Preliminary Works

  These include:
  

  1. Construction of residential buildings for the construction staff which will be allocated for the maintenance staff in the future. The contract of this has already been signed with the Corporation of the Irrigation Works and about 80% of the building has been completed. The geological studies for sites of building materials has been completed by some relevant governmental departments under the consultancy of Sir Alexander Gibb & Partners (UK) and Queen & Pelierre (France).
  2. Carrying out of a census for the residents in the expected submerged area after the completion of the dam heightening. This was completed by the Department of Statistics.
  3. Determination of the expected submerged area after the completion of the dam heightening. This was completed by the Department of Surveying.
  4. Study of the environmental and social impacts of the dam heightening. This was completed by “Ja’afar Karrar & Partners”.

• The Concrete-dam Works

  The length of the existent concrete dam is 1000 metre with a height of 492 m (above the sea level) that provides for supporting a water level of 480 m. In order to support a water-level of 490 m, it is required to be heightened by extra 10 m and strengthening of the buttresses. The required quantities of the construction materials are:
  

  1. Concrete work (118000 cubic metre)
  2. Steel Reinforcement (3300 tonnes)
  3. Formworks (82000 square metres)

• The Earth-dam Works

  The length of the existent earth dam is 12.5 km of which there is 4 km on the Eastern bank and 8.5 on the Western bank. The required earth-dam after heightening is 25 km of which there is 9 km on the Eastern bank and 16 on the Western bank.. The volume of the earthwork required for this project is 20.32 million cubic metres which is composed of :
  

  1. Pure Sand (5.82 million cubic metres).
  2. Pure Sealant Clayey Soil (3.11 million cubic metres).
  3. Clayey Sand (5.05 million cubic metres).
  4. River Gravel (5.75 million cubic metres).
  5. Rock masses (0.77 million cubic metres).

• Mechanical and electrical works

  These include:
  

  1. Installations of the cranes for new required levels.
  2. Rehabilitation of some of the existent dam works such as gates.
  3. Installation of gates for the canals for Kenanna and ElRahad schemes.
  4. Installation of generators on the out-lets of canals.

• Reservoir Works

  These covers:
  

  1. Cleaning of the expected expansion of the reservoir on heightening..
  2. Reallocation of 73,000 people from the expected submerged area, and this requires co-ordination with the government of the Blue Nile region.

• Consultants Work

  This includes:
  

  1. The preparation of contracts documents for the concrete & earth dams and mechanical & electrical works.
  2. Design of the project and preparation of the construction plans.
  3. Supervision of the construction stage.

Cost of the Project

The total cost of the project is estimated to be 360 Millions American Dollar, distributed as follows:

1. Earth-dam (160 Millions).
2. Concrete-dam (75 Millions).
3. Equipment (60 Millions).
4. Preliminary Works (30 Millions) &
5. Consultants and project management (35 Millions).

Funds for the Project

The Ministry of Finance (Sudan Government) is the sole fund provider for this project. It is recognised that about 60% of the total cost can be provided in local currency, while 40% of the total cost is required as hard currency to import the electrical & mechanical equipment and steel, and pay the consultants. Due to the lack of foreign funds, foreign companies did not submit tenders for the construction of earth- & concrete-dams. The Ministry of Finance was able to get an equivalent of 22 Millions American Dollars loan in local currency from the Islamic Development Bank-Jeddah to fund the dam heightening. The expenditure from this loan has started in 1996/1997 on the earth-dam works.

Plans for Construction

The basic strategy of the construction is to maximise the utilisation of the local expertise in the project, established a special executive unit for this project.consequently:

1. The earth-dam works was contracted to the Public Corporation for Excavation & Irrigation Works which
2. The consultants were selected from national experts with exception to the highly specialised fields when foreign consultants have been employed.

Construction Programme

It was planned, provided that all the qualitative and quantitative funds are available, to finish the whole project in a six years period; 3 years for the construction of the concrete dam and 6 years for the construction of the earth-dam which will be carried out in parallel with the concrete dam construction. But, the reality of lacks of funds has made this impossible and the construction is constrained with the seasonal and annual variations of the fund situation. This, of course, makes it difficult to visualise any realistic time scale for finishing the project.

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