Flood risks and strategies

Question 1

How is heavy rainfall a flood risk?

Answer 1

Heavy rainfall means that water arrives too quickly to infiltrate, so there’s a lot of surface run off, which increases discharge

Question 2

How is prolonged rainfall a flood risk?

Answer 2

Prolonged rainfall can saturate the soil. Any further rainfall can’t infiltrate, increasing runoff into river channels

Question 3

How is geology a flood risk?

Answer 3

Clay soils and some rocks e.g granite and shale, are impermeable (they don’t allow infiltration) so surface run off is increased

Question 4

How is relief a flood risk

Answer 4

If a river is in a steep-sided valley, water will reach the river channel quicker because it can flow faster down the steep slopes. This rapidly increases discharge

Question 5

What is hard engineering?

Answer 5

Man-made structures built to control the flow of rivers and reduce floodiing

Question 5

What is soft engineering?

Answer 5

Schemes set up using knowledge of a river and it’s processes to reduce the effects of flooding

Question 6

Dams and resevoirs