5.5 Flashcards
What are the causes of flooding?
- Intense storms
- Heavy rainfall
- Monsoons
- Prelonged rainfall
- Snowmelt
What is the main reason for flooding, which is common across all causes?
- Reduced surface runoff
- Satured ground for prolonged, heavy and monsoon rainfall as well as monsoon rain
- Frozen ground for snowmelt
How do humans cause flooding?
- Landuse change
- Building on floodplains
- Hard engineering
How does landuse change cause flooding?
Removal of vegetation causes interception rates to decrease as well as the amount of evapotraspiration. The means more water must be absorbed leading more surface runoff as the ground is saturated.
How does flood plane use impact flooding?
Population pressure mean that floodplains are built upon, despite protection measures floods still occur
How does hard engineering impact flooding?
Infrastructure such as bridges casue the channel to be restricted causing flooding upstream, if the bridge collaspes flooding will suddenly occur down stream.
-Artifical levees allow for a bigger channel capacity, however the river flows quicker causing theflooding downstream
What impacts does flooding have on ecosystems?
- Small floods allow water levels to be replenished
- Large floods cause soil and channel erosion releasing sediment into the river damaging ecosystems and polluting the water.
How does flooding impact the soil?
Soils may become water logged increasing surface flow. In the long term nutrient ric sediments are provided.
