Flooding Flashcards
Flood
Water extends past normal limits
Physical factors
Natural
Human factors
Man made
Process of flood
1 - rains heavy
2 - rain can’t soak into ground fast so water runs over surface into river
3 - river Lebel rises rapidly. River floods
Heavy rain
Physical + water can’t infiltrate
Soggy soil
Physical + soil already full can’t take anymore water
Impermeable rock
Physical + water can’t pass through
Steep slopes
Physical + water runs down quickly
Built up areas
Human c more impermeable surfaces
Loss of trees (deforestation)
Less interception + less water soaked up + less transpiration + human
Flat flood plain
Physical + easily flooded
Tributaries
Physical + more tributaries = greater risk of flooding
Bridges + culverts
Human + make rivers narrower restrict flood
Build dams
+ controls flow of water.
+ water flow used to generate energy - hydro electricity power.
- expensive and land has to be flooded
Levees + concrete
+ tall levees mean river holds more water.
+ concrete banks smoother and speed flow.
- spoils look of river.
Loss of wildlife habitats
Plant trees
+ intercept more water and absorb some
- take years to reach maturity and needs lots of space.
Widen river
Digging out a larger channel
- loss of wildlife habitat
Deepen river
Dig out deeper channel
- loss of wildlife habitat
Straighten river
Speeds flow.
Controlled flooding
Planners allow designated areas to flood so it doesn’t affect cities and town downstream
Overflow channel
An extra channel that a can be opened when there is a risk of flooding.
