Hard Engineering

• Hard engineering

  Man-made structures built to control the flow of rivers and reduce flooding.
• Dams and reservoirs

  Dams are obstructions in water that create reservoirs, preventing water from flowing downstream.

  Reservoirs are artificial lakes that form behind a dam
• What are the advantages of dams and reservoirs?

  Dams store water, it controls the flow of water, prevents flooding downstream, can also be used to produce hydroelectric power
• What are the disadvantages of dams and reservoirs?

  Dams are very expensive to build. Creating a reservoir can flood existing settlements.

  Eroded material is deposited in the reservoir and not along the river's natural course so farmland downstream can become less fertile.
• Channel straightening

  Removers meanders creating a straighter route

  Flood risk is reduced as water leaves the channel faster

  Faster moving water means more erosion downstream so more potential floods downstream
• Embankments

  Raised banks constructed along the river; they effectively make the river deeper so it can hold more water. They are expensive and do not look natural but they do protect the land around them.
• Flood relief channels

  Building new artificial channels which are used when a river is close to maximum discharge. They take the pressure off the main channels when floods are likely, therefore reducing flood risk.

  - Gates are used to control flow HOWEVER the relief channels rejoins water causing more floods