Flooding Prevention Methods

Question 1

Dams. Pros and cons too

Answer 1

Built to control discharge. It holds back water allowing it to be released in a controlled way.
Con: expensive, and ugly and big
Pro:can be a source of drinking water

Question 2

Channelisation

Answer 2

Man made river structuring. Reduces water friction with the bed and banks speeding up water flo, gets water away from an area quickly.
Con:causes there to be a flood more likely further downstream as velocity I reduced which causes sedimentation of the channel.
Pro:reduces length of river and moves water out quickly

Question 3

Levees

Answer 3

Increases the potential maximum area of the river channel, allowing it to hold more water before bursting its banks.
Con: if they burst more damage than before, higher maintenance cost
Pro: cheap and used for footpaths

Question 4

Afforestation

Answer 4

Trees slow down the flow of water towards the river channel and also allows more interception (reducing overall runoff). The roots and soil absorb the water
Con: you have to pay for the land, takes time to grow, loss if grazing land
Pro: more carbon dioxide absorbed, new habitats, inexpensive, reduces water flowing downstream

Question 5

Floodplain zoning

Answer 5

Consider the floodplain and try to avoid building on the areas which are most regularly flooded. Area closest to channel used for farming.
Cons: difficult to get planning permission, difficult if houses are already built there
Pro: low cost

Question 6

Flood warning system

Answer 6

Allows evacuation of areas likely to flood and therefore reduction in damage by warning people in advance
Cons: relies in people to listen, does not help people prone to flooding
Pros: very cheap, can protect their valuables earlier

Question 7

Retention ponds

Answer 7

Allows runoff or be temporary pond to store the water.
Cons: no reduction in runoff volume, not suitable for steep sites, hazard, takes up space
Pros: provides a habitat, improved water quality, looks natural,