fw.2.1 Flood risk within a drainage basin

News article

‘We feared we’d all be drowned’: the Indian floods that killed more than 100 and left thousands homeless

More than 2,600 villages have been flooded in Assam this year, in a climate disaster made worse by uncontrolled deforestation and mining in the region

The Guardian · 14 August 2026

Key terms

• Channel modifications
  • Alteration of a channel by changing the physical dimensions or materials of its bed or banks. Channel modification includes damming, rip-rapping (or other armouring), widening, deepening, straightening, relocating, lining and significant removal of native vegetation from the bottom or banks.

• Deforestation
  • The removal of a forest or stand of trees from land that is then converted to non-forest use.

• Distribution
  • Spread over an area.

• Drainage basin
  • The area of land drained by a river.

• Dredging
  • Dredging is the excavation of material from a water environment.

• Flood risk
  • The measure of vulnerability to flood with consideration to the likelihood of flooding and the total value of the assets at risk.

• Frequency
  • The rate at which something occurs over a particular period of time.

• Levee
  • Can be naturally occurring ridge structures that form next to the bank of a river, or be an artificially constructed fill or wall that regulates water levels. A structure that is usually earthen and that often runs parallel to the course of a river in its floodplain.

• Magnitude
  • The great size or extent of something.

• Overland flow
  • The movement of water across the surface of the land, usually when the ground is saturated, frozen, or when rainfall is too intense for infiltration.

• Urbanisation
  • The process by which an increasing percentage of a country’s population comes to live in towns and cities. It may involve both rural–urban migration and natural increase.