Theme 1B

• Channelisation is when rivers are managed by modifying or adjusting the channel itself through which the water flows. It is done to prevent flooding of settlements or farmland, the protect banks and the land either side from erosion, to improve drainage and to maintain navigational channels.
• Channelisation includes: realignment, dredging, levee construction and re-sectioning. It is an expensive way to manage the river but these costs are considered less than the cost of any flood damage.
• Some advantages to channelisation include:
• Some advantages to channelisation include:

  • Flood prevention (social, economic and infrastructural consideration)
  • Maintaining river transport links (economic, social, communication infrastructure)
• Some disadvantages to channelisation include:

  • Relocation of flooding problems
  • long term and short term costs
  • aesthetics
  • ecology (wildlife and habitat endangerment)
• Hard engineering refers to methods that involve structural engineering solutions, such as dredging, artificial levees, re-sectioning and realignment.
• Soft engineering techniques are methods that work with the natural river processes and interfere less with the channel and ecosystem.
• Sustainable management refers to approaches to the management of a river through methods that do not impact upon the rivers ecology or cause recurring costs. They must work naturally with the river.
• Sustainable river management methods include:

  • afforestation
  • land use zoning
  • designation of flood prone areas to facilitate overspill.