AS AQA Rivers- Hard Engineering
- Created by: kkwills
- Created on: 15-05-16 13:05
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- Rivers: Hard Engineering
- Dams
- Dams are huge walls built across rivers. A reservoir is formed behind. Flood water is caught by the dam to prevent flooding downstream and the water is realised steadily throughout the year.
- Turbines are often built into the dam to help create electricity and people can use the reservoir for recreational activities such as sailing.
- Steady water release allows the irrigation of land below the dam throughout the year.
- Down Sides
- They're very expensive
- Land is flooded when a reservoir is created- farmland is lost and people are forced to move elsewhere
- They trap sediment normally carried in rivers. This can cause a dam to fail. It can also cause increased erosion further downstream.
- Affects wildlife e.g. it may prevent salmon from migrating upstream to breeding grounds.
- Levees
- Levees are embankments built along rivers. The river can hold more water so flooding occurs less often
- They allow the flood plain to be built on
- Down Sides
- They're quite expensive to build.
- There's a severe risk of flooding if the levees are breeched.
- Channel Staightening
- Channel straightening is where meanders are removed by building artificial cut-through. This makes the water flow faster, which reduces flooding because water drains downstream more quickly and doesn't build up to a point where a river cannot take it anymore.
- It takes less time to navigate the river as it has been made shorter.
- Down Sides
- Flooding may happen further downstream instead, as water is carried there faster.
- More erosion is caused downstream because the river flows faster.
- Altering river channels disturbs wildlife, and habitats.
- Dams
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