Hard and Soft Engineering

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  • Hard Engineering and Soft Engineering.
    • Engineering can reduce the risk of flooding or the effects.
    • Hard engineering = man made structures built to control the flow of rivers and reduce flooding.
    • Soft Engineering = schemes set up using knowledge of the river and its processes to reduce the effects of flooding.
    • Hard Engineering.
      • Dams and reservoirs.
        • Dams (big walls) are built across rivers. A reservoir is formed behind the dam.
          • Pros: reservoirs store water which reduces risk of flooding.
            • Cons: dams are expensive to build. Creating a reservoir can flood settlements. Eroded material is deposited in the reservoir, not along the natural course so farmland downstream can be less fertile.
      • Channel straightening.
        • The rivers channel is straightened by building artificial channels.
          • Pros: water moves quicker because it doesn't have to travel as far which reduces the risk of flooding.
            • Cons: Flooding may happen downstream of the straightened channel as water can get there quicker. There's more erosion downstream because water is flowing faster.
    • Soft Engineering.
      • Flood warnings.
        • Environment Agency warns people about possible flooding through TV, radio, internet and newspapers.
          • Pros: impact of flooding reduced- warnings give time for people to move belongings upstairs, place sand bags and evacuate.
            • Cons: doesn't stop flood from happening. Living in a place with lots of warnings could make it hard to get insurance. People may not hear/ have access to warnings.
      • Preparation.
        • Buildings are modified to reduce amount of damage a flood can cause. People plan what to don in a flood- keep important things upstairs and keep items like torches and blankets in an accessible place.
          • Pros: impact of flooding is reduced- building are less damaged, people know what to do. People will worry less.
            • Cons: doesn't guarantee safety, could give a false sense of security, expensive to modify homes and business.
      • Flood plain zoning.
        • Restrictions prevent building on parts of the flood plain that are likely to be affected by a flood.
          • Pros: risk of flooding reduced by less impermeable surface created. Impact of flooding reduced- no houses or roads that can be damaged.
            • Cons: expansion od urban area is limited if there are no other suitable building sites. Can't help areas that have already been built on.
      • 'Do nothing'.
        • No money is spent on engineering methods or maintaining existing methods. Flooding is a natural process- people should accept risks of living in areas that can flood.
          • Pros: the river floods and eroded material is deposited on the flood plain which makes farmland more fertile.
            • Cons: risk of flooding and impacts aren't reduced. A flood will probably cause a lot of damage.


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