Human factors of flooding

Question 1

How does urbanisation cause flooding?

Answer 1

Impermeable tarmac and concrete
Rapid surface runoff
Gutters and drains increase runoff
Reduce lag time, which increases discharge

Question 2

How does deforestation cause flooding?

Answer 2

Reduces interception and evapotranspiration
Increases volume of water reaching channel, which increases discharge
Loose soil is carried to the river
Raises the river bed, reducing channel capacity