Storm hydrograph and channelisation - WATER CYCLE

Question 1

Key words (7)

Answer 1

• Peak rainfall
• Rising limb
• Falling limb
• Peak discharge
• Bank fall discharge
• Base flow.
• Lag time (time it takes from peak rainfall to peak discharge)

Question 1

Why is the rising limb important?

Answer 1

• can tell the flood forecasters how fast the peak discharge will be reached.
• The faster it is reached the more likely a flood occurring

Question 2

Storm flow

Answer 2

Water that arrives in the river via surface run off or rapid through flow.

Question 3

Physical factors affecting storm flow

Answer 3

• Climate
• Droughts

Question 4

Human factors affecting storm flow

Answer 4

• Urbanisation
• Deforestation

Question 5

What is Channelisation?

Answer 5

• Refers to river and stream channel engineering for flood control, navigation, drainage improvement and reduction of channel migration protection.
• it is done to enlarge channel capacity, prevent flood-plan connectivity and can inable very high flow velocity within the river channel during a flood
• It involves activities such as channel enlargement through widening or defining and changes in channel platform ( equilibrium in the form of a channel)

Question 6

What is the impact of channelisation? ( 3 factors)

Answer 6

• modify sediment supply
• remove important habitats within the channel
• increase flow energy/ flow resistance