Factors increasing flood risk (Bangladesh)

• Local

  • Height above sea level - most elevations are less than 10m above sea level
  • Subsidence - clearance and drainage of more than 50 large islands
  • Removing vegetation - 71% of Bangladesh's mangrove-forested coastline is retreating by as much as 200m a year
• Global

  • Sea level rise - global warming
  • Storms - Cyclone Sidr 2007
• Impacts of Cyclone Sidr

  • Strong winds of up to 223km/hr
  • Storm surge up to 6m high
  • 3,363 deaths
  • Cost of US$1.7bn
  • 55,282 injured
  • 16,954 educational institutions damaged
• Storm surge


  • Changes in sea level resulting from variations in atmospheric pressure and associated winds
  • Occur on top of normal tides and when positive surges are added to high tides or in association with strong winds they can cause extreme water levels and flooding
  • Most commonly produced by the passage of (extra-)tropical depressions
  • Can have devastating impacts especially when there is management of coastal defences