Lesson 8 - Human Causes of Flooding

Question 1

What are the 4 main human causes of flooding?

Answer 1

Urbanisation
Deforestation
Floodplain Drainage
Flood Mismanagement

Question 2

How does urbanisation result in flooding?

Answer 2

Increasing impermeable surfaces
SRO
Drainage systems shorten lag times
Bridges + culverts reduce river capacity

Question 3

How do bridges + culverts reduce river capacity?

Answer 3

Aim to divert water under infrastructure + away from main channels

Question 4

How does deforestation result in flooding?

Answer 4

Reduced interception + evapotranspiration
SRO, water reaches channels quickly
Soil erosion

Question 5

How does soil erosion affect flooding?

Answer 5

Increased river sediment load
River bed ‘rises’
Less capacity to carry water

Question 6

How does floodplain drainage result in flooding?

Answer 6

Drainage reduces natural storage capacity of plains
Land may shrink + become lower lying

Question 7

Where is floodplain drainage common?

Answer 7

Developed economies
Provide agri + urban land

Question 8

How does flood mismanagement result in flooding?

Answer 8

Actions upstream may adversely affect downstream regions

Question 9

How is hard engineering sometimes an example of flood mismanagement?

Answer 9

Large volumes diverted
Unprotected areas + choke points vulnerable