Study

Managing flood risk

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  • An advantage of River restoration (restoring the river's original course)
    Can slow rivers down preventing flooding downstream by removing levees & restoring meanders or more attractive or habitats for wild life.
  • What is the term for barriers that hold back water and the term for the artificial lake behind it?
    Dam & Reservoir
  • A disadvantage of dams and reservoirs.
    Sediment is trapped behind the dam, reducing the amount carried downstream to floodplains, which lowers alluvium deposition, therefore reduces soil fertility.
  • What is an advantage of washlands?
    Safe place for floodwater preventing it from affecting valuable areas or Deposited alluvium is fertile which may be useful for agricultural use.
  • What is the name for an area of the flood plain that are allowed to flood and one disadvantage?
    Term: Washland / Disad: Land that could have been developed on, for example, for housing is unusable.
  • A disadvantage of embankments (manmade levees)
    Embankments increase channel capacity, so if they fail a large volume of water is released suddenly causing even more damage.
  • What is the term for plating trees as a flood management technique
    Flood Abatement (Afforestation)
  • What are the disadvantages of channelisation?
    Increasing the discharge (amount of water flowing past at a given time) can threaten further downstream after heavy rain.
  • A disadvantage of Flood Abatement
    Coniferous trees are often planted as they grow fast but they increase soil acidity through needle litter, which can reduce soil fertility therefore affecting
  • An advantage of embankments (man made levees)
    They can have walkways or roads on top of them increasing the amenity facilities in the area-multi purpose.
  • Give 2 advantages of dams and reservoirs.
    1. HEP (Hydroelectric Power) 2. Water Supply 3. Water Sports
  • What is the advantage of channelisation?
    Reduces channel friction, increasing velocity (water speed) increasing discharge which reduces the risk of flooding in that area.
  • What is an advantage flood plain zoning?
    Aims to prevent the development of homes/businesses in high risk areas.
  • How does planting trees (afforestation) act as a flood managment?
    The trees intercept the rain water reducing surface runoff
  • What is the term for extra channels built next to rivers or leading from them and an advantage?
    Term: Flood Relief Channels / Adv: The river can be re-routed to by-pass settlements under threat.
  • The term used for Governments allocating areas of land to different uses, according to their level of flood risk.
    Flood Plain Zoning
  • What is the term for deepening and/or straightening the the river?
    Channelisation
  • What is an embankment (manmade levee)
    High banks built on/near river banks