River flooding is an important natural hazard. Rivers which rise quickly after rainfall are described as having a flashy hydrograph. Flooding is a natural phenomenon, but it becomes a hazard to life and property when floodplains are used for human activity. Human activity in drainage basins often makes flooding more likely (e.g. by deforestation or urbanisation).
Causes of floodingEdit
Impacts of floodingEdit
Flooding is a hazard in both MEDCs and LEDCs, but the impacts are different. In MEDCs, flooding causes major financial damage but loss of life is rare. In LEDCs, poor warning and evacuation systems mean that loss of life is higher.
Classic MEDC case studies include:
- Mississippi flooding of New Orleans, August 2005, caused by Hurricane Katrina
- Flooding of Boscastle, Cornwall, August 2004
LEDC flooding case studies include
- Bangladesh, 2007: Most of Bangladesh is on the low-lying floodplains of the Ganges, Brahmaputra and Meghna rivers, and densely populated with subsistence rice farmers. It has suffered many catastrophic floods, including 1988, 1998 and 2007.
- Burma, 2008: The fertile alluvial soils of the Irrawaddy Delta are also intensively farmed for rice. Cyclone Nargis caused devastating flooding in May 2008 in which 130000 people are estimated to have died.
River basin managementEdit
Short, medium and long-term approaches to flood prevention
Hard engineering strategies
Soft engineering strategies