4.7 River landscapes and human activity

Question 1

Explain how human factors (urbanisation, land-use change and
deforestation) can affect flood hydrographs.

Answer 1

Human factors can affect flood hydrographs. Urbanisation will increase the amount of impermeable rock and there fore will decrease percolation and increase surface run off. Deforestation will increase surface run off and decrease interception and evaporation as water normally gets caught in trees and evaporates but now cannot so it will get to the river quicker as surface run off.

Question 2

Explain how physical and human factors cause river flooding in the River Eden.

Answer 2

One natural cause was because of the sheep, the sheep would be grazing on the fields eating grass and shrubs, this would increase surface run off and cause the water to get to the river faster. One human factor is urbanisation, by building roads and houses will make a larger area of impermeable surface this will mean there is less infiltration meaning the surface runoff and surface storage will increase. Another natural reason why the river eden flooded was because of storm Desmond, storm Desmond caused 341 mm of rain to fall in a day which means that the floor will be saturated decreasing infiltration and increasing surface run off