Case Study: Multipurpose Water Schemes
- The number of dams being built around the world is increasing
- This increase is due to the need to manage water supply due to:
- Water shortages
- Increased water demand
- There is conflict between people who say more dams should be built and those who do not think more dams should be built
- Advocates of building more dams believe that the structures act as buffers against extreme water flows
- They contain water during flooding and then release the water in times of drought
- Opponents of dam building believe that there are significant impacts on ecosystems
- There is scientific research which says that the reservoirs created by dams emit more greenhouse gases
- The flooding of valleys to create reservoirs destroys habitats
- Advocates of building more dams believe that the structures act as buffers against extreme water flows
- Recently, there has been minimal building of dams in Europe and North America
- In countries such as China and Brazil, dams are built as multipurpose schemes
- The dams are used to:
- Control of river flooding
- Produce hydropower - Hydropower from dams now supplies 17% of global energy production
- The dams are used to:
- Floods caused by dam failure can be very destructive
- Dam failure can be caused by:
- Seepage
- Internal erosion
- Landslides
- Earthquakes
- A breach in the dam
Grand Ethiopian Renaissance Dam (GERD)
- Ethiopia began constructing the Grand Ethiopian Renaissance Dam in 2011
- The dam is located along the Blue Nile downstream of the Tana Lake
Location of the Grand Ethiopian Renaissance Dam
- Tana Lake has an average altitude of 1800 m
Facts about GERD
Ethiopian Gerd Dam
- The Grand Ethiopian Renaissance Dam:
- Is a roller-compacted concrete-type dam
- Has two power stations, three spillways and a saddle dam, which is a secondary dam
- Will be Africa’s biggest hydroelectric plant
- Cost US$5 billion
- Stands 170 metres tall
- Began generating electricity in February 2022
- Has created a reservoir containing 74 billion cubic metres of water
Saddle Dam of the GERD
- Chinese banks invested and provided loans to the Ethiopian government for the construction of the dam
Advantages and Disadvantages of the GERD
| Advantages of building the dam | Disadvantages of building the dam |
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GERD will be used to generate hydropower with an installed capacity of 6 000 megawatts |
Countries downstream are concerned about water availability - it will reduce water supplies to downstream Egypt by more than one-third |
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The Ethiopian government estimates that the GERD can generate up to 2% of the country’s annual GDP |
The dam may alter the natural flow of the Nile, which could potentially affect ecosystems and biodiversity downstream |
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Improved water control could allow for the expansion of agricultural land by an estimated 2 million hectares |
In periods of ongoing drought, there may be a possibility that the reservoir exacerbates water scarcity downstream |
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The dam includes a flood retention basin, which can provide protection downstream during periods of heavy rainfall |
The construction of the dam has resulted in the displacement of communities |
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The dam has a storage capacity of 74 billion cubic metres, which can act as a strategic reserve during drought |
Geopolitical disagreements have taken place because there has been a lack of comprehensive agreements about the operation of the dam between all countries |
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Ethiopia has taken the diplomatic route of working with Egypt to resolve water disputes |
The construction of the dam was delayed, meaning that it went over the expected budget |
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Hydropower is a clean resource, which means that Ethiopia can reduce its carbon emissions |
Possible increase in waterborne diseases |
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Ethiopia invested heavily in infrastructure by constructing over 15,000km of transmission lines, which has contributed to the development of the region |
Egypt has said that they have concerns over the structural integrity of the dam and its potential to fail |
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Ethiopia could double their electricity production, which is useful for the 60 million people who do not currently have access to electricity |
Egypt relies on the Nile for 97% of its water needs |
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The dam is designed to trap 100 years of sediment inflow |
The UN has said Egypt could run out of water by 2025 |