Please enable JavaScript.

Coggle requires JavaScript to display documents.

River Management, Flood Enbankment - Coggle Diagram

- - - - It looks natural, promotes wildlife biodiversity and is relatively cheap compared to hard-engineering.
      - During large flash floods vegetation can be easily removed.
  - - - Can't protect aganist big floods and may have to coincide with zoning.
      - This looks natural, is attractive and can attract wildlife. Can allow the floodplain to become more fertile.
  - - - They remove pressure of the main river and areas of high land value. They may also develop into new habitats for plants and animals.
      - They are expensive, may also flood in times of heavy rainfall and may restrict future urban growth.
  - - - By enlarging the cross-sectional area you are increasing the bankfull discharge of the river along with its hydraulic radius. This will increase the velocity of the river and reduce the chances of it flooding in the immediate area by moving the floodwater further downstream.
      - If buildings are built up to the river bank it might not be possible to enlarge the channel. Also the process can be expensive and can cause problems to areas downstream who are receiving more flood water quicker, but with an un-enlarged channel.
  - - - They take the pressure off the main channels when floods are likely therefore reduce flood risk.
      - It can be hard to find land to build relief channels, they are expensive and when empty can become areas to dump rubbish, etc. If river levels rise significantly it is also possible for relief channels to flood as well.
- - - - It is expensive and is not natural so vegetation and animal life will find it harder to grow and live. Flooding may be caused downstream of the channelised area.
      - Reduces friction and increases velocity of river, removing water from the channelised area quicker. Bank erosion is also reduced.
  - - - Collected debris must be cleared after flood events. May interfere with river ecosystems.
      - Reduces flood risk in main river. Often installed in isolated places. Relatively easy to install.
  - - - Groins are easily added to rivers and can be moved or changed. Provide a habitat for river wildlife and increase biodiversity.
      - Require engineering projects. Change the flow of rivers and may move erosion and deposition processes to other areas of the stream.
  - - - This can be done on an individual level and can be relatively cheap. Temporary protection can be removed under normal circumstances so it does not change the aesthetics of properties.
      - Temporary defences can usually only protect against minor floods. Not everyone will be happy with having to redesign their houses.