The effects of and responses to floods vary between areas of contrasting levels of wealth.

For this section of the unit you need two case studies, one from a richer area of the world – Boscastle, UK and one from a poorer part of the world – Dhaka, Bangladesh. You need to be able to compare and explain the different effects of and responses to flooding.

  Boscastle, UK Dhaka, Bangladesh

16th August 2004

Village built at the confluence of the River Jordan and the River Valency


Severe floods in 1998 and 2004

Confluence of three rivers: Meghna, Ganges, Brahmaputra


Causes Natural

  • Torrential rain: over 500mm rain fell in 4 hours, remnants of Hurricane Alex. Weather system remained stationary over area due to converging winds.
  • Small catchment area (about 23km2)
  • Impermeable upland area (Bodmin Moor)
  • Steep-sided valleys

Extremely wet summer, by August ground was saturated.

  • Confluence of three large rivers
  • Snow melt from Himalayas
  • 70% land area <1m above sea level
  • Cyclones create storm surges
  • Increased surface runoff and more soil erosion means silt blocks river channels reducing carrying capacity of river
  • 80% floodplain and delta makes Bangladesh very susceptible to flooding

Monsoon rainfall Human

  • Building along river
  • Construction of small bridges across river (trapped material behind them creating small dams)
  • River narrowed through Boscastle reducing capacity

Deforestation in valleys

  • Deforestation in Himalayas
  • Ganges diverted for irrigation increasing silt deposition
  • Rapid unplanned urbanisation in Dhaka

Effects Social

  • Destroyed homes
  • Stress and anxiety for local people

Cars belonging to more than 1,000 people washed away

  • Hundreds killed
  • Millions made homeless

Contaminated water led to disease Economic

  • 25 business properties destroyed
  • Bridges and roads damaged
  • 4 footbridges washed away
  • Visitor centre destroyed
  • Area relies on tourism for 90% income, most of which earned in summer months. Floods dramatically affected earnings.
  • Insurance companies paid out an estimated £20 million to repair damaged property
  • Over 900 bridges destroyed
  • 15,000km road damaged
  • Crops lost leading to food shortages
  • Financial losses for businesses and shops
  • Communications damaged making co-ordinating rescue efforts difficult


  • Gardens and pavements destroyed by weight of floodwater
  • Agricultural land flooded and contaminated by polluted water

Responses Short-term Major incident declared at 5pm. RAF search and rescue were alerted to rescue trapped people. No-one died mainly due to the rapid response of the emergency services.

  • Farmers provided with free seeds
  • Foreign aid (including £21million from UK)
  • Water purification tablets
  • Food aid


To reduce the risk of future floods, a £4.6 million flood defence scheme was completed in 2008.

  • Low bridges removed
  • River widened through Boscastle
  • New flood defence wall built in village centre
  • River bed lowered by an average of 0.75m
  • Trees near to river removed
  • Landowners encouraged to maintain vegetation cover on valley sides

Dhaka Integrated Flood Protection Project

  • Cluster villages (raised by 2m) and raised homesteads (individual homes raised by 2m on earth banks)
  • Flood shelter: about 2ha of raised land where people can bring livestock. Each shelter has space for over 100 families and includes a toilet
  • Radios to issue warnings
  • Embankments to hold back rising water
  • Sluice gates (able to close channel when water rises)
  • Slope protection (to reduce erosion of embankments)