Factors that increase flood risk

• what are local factors that increase flood risk

  height, subsidence, vegetation removal
• why does height affect flood risk

  low lying areas (only 1-2m above high tide sea level) more likely to flood

  • long term flooding caused by rising sea level
  • short term flooding caused by storm surges
• how many metres above high tide sea level are low lying coastal areas

  1-2 metres
• what is subsidence


  A sinking of the ground surface
• what are natural causes of subsidence at deltas

  sediment deposited which puts pressure on the surface
• what is a delta

  An area of sediment deposited at the mouth of a river
• what are human causes of subsidence at deltas

  • humans live there due to agricultural opportunities (fertile soil) so they build infrastructure which is heavy
  • they also abstract groundwater
• where is vegetation removal a problem for flooding

  mangrove forests
• why are mangrove forests destroyed

  • fish farming as mangroves are fisheries
  • for supplies such as timber
• where are mangroves being destroyed

  Bangladesh and india
• why are mangroves beneficial

  • a 100km belt of mangrove can reduce wave height by 40%
  • fisheries
  • protect coastline