Lesson 8 - Human causes of flooding

Question 1

Give four human causes of flooding?

Answer 1

• Urbanisation
• Deforestation
• Flooding mismanagement
• Floodplain drainage

Question 2

How does urbanisation increase the risk of flooding?

Answer 2

Urbanisation leads to the expansion of impermeable surfaces such as roofs, roads and patios. This means that there is less infiltration and more surface runoff, therefore increasing the risk of flooding.

Question 3

How much land is taken up in London by car parks?

Answer 3

Approximately 25 kilometres squared

Question 4

How does deforestation increase the risk of flooding?

Answer 4

Deforestation leads to less interception and more surface runoff, meaning the lag time decreases. Furthermore, soils are exposed to greater rates of erosion, there is an increased volume of sediment load and deposition, thus reducing the size of the river.

Question 5

What is flooding mismanagement?

Answer 5

Flooding mismanagement - alterations at one point in a drainage basin can cause negative consequences further downstream.

Question 6

Why is floodplain drainage common in developed countries?

Answer 6

Floodplain drainage is common in developed countries to provide land for agriculture and the expansion of urban areas.

Question 7

Why does floodplain drainage lead to flooding?

Answer 7

The drainage process reduces the natural storage capacity of the floodplain, especially where natural wetlands are lost.