Multipurpose Dam Projects (Copy)
4.6 Multipurpose Dam Projects – Cheat Sheet
Choice of Site
| Factor | Explanation | Example |
|---|---|---|
| Geology | Strong rock foundations to support dam wall | Aswan High Dam, Egypt |
| Topography | Narrow valley to store large volume with smaller wall | Hoover Dam, USA |
| Water Supply | Reliable river with sufficient flow | Three Gorges Dam, China |
| Accessibility | Road/rail links for construction materials & workforce | Kariba Dam, Zambia/Zimbabwe |
Impacts of Multipurpose Dams
| Type | Positive Impacts | Negative Impacts |
|---|---|---|
| Environmental | Reservoir creates habitats, can regulate flooding | Loss of ecosystems, submergence of land, methane emissions from rotting vegetation |
| Economic | Generates hydro-electric power (cheap, renewable); irrigation for agriculture; boosts industry | Very high construction/maintenance costs |
| Social | Provides water supply, jobs, improved infrastructure | Displacement of communities, loss of cultural sites |
Sustainability
- Provide renewable energy (HEP) → reduces fossil fuel use.
- Long lifespan if well maintained, but reservoirs can silt up, reducing efficiency.
- Climate change (altered rainfall patterns) can reduce reliability of dam projects.
Case Study Examples
- Three Gorges Dam (China): World’s largest HEP project; huge energy supply but displaced over 1 million people.
- Aswan High Dam (Egypt): Provides irrigation & HEP but caused downstream erosion and loss of Nile silt fertility.
Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Environmental Management Full Scale Course