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

Map of northeastern Africa highlighting the Aswan High Dam, Rosieres Dam, and Grand Ethiopian Renaissance Dam. Annotations note Ethiopia's hydropower project and rural population.
Location of the Grand Ethiopian Renaissance Dam
  • Tana Lake has an average altitude of 1800 m

Facts about GERD

Illustration of a dam with water being released. Text indicates water control by the dam and describes roller concrete as a special mix preventing slumping.
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

A dam structure diagram showing the reservoir, main dam, saddle dam, and spillway, with arrows pointing to each labeled part in the landscape.
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

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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