Contemporary Dam Building (DP IB Geography): Revision Note
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
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
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
Tana Lake has an average altitude of 1800 m
Facts about GERD
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
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 |
|---|---|
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 |
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 |
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 |
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 |
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 |
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 |
Hydropower is a clean resource, which means that Ethiopia can reduce its carbon emissions | Possible increase in waterborne diseases |
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 |
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 |
The dam is designed to trap 100 years of sediment inflow | The UN has said Egypt could run out of water by 2025 |
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