EQ5 – what are the challenges for rivers and how can they be managed?

Question 1

Why is river flood risk increasing? Include global climate change and human activity in drainage basins

Answer 1

Flood risk is increasing because of: heavy rainfall, long periods of rain, snowmelt, steep slopes (leading to quicker surface run off), impermeable rock (more surface run off), compacted and or saturated soils.

Human factors: urbanisation, building on flood plains and deforestation

Question 2

Compare how soft and hard engineering schemes work

Answer 2

Soft engineering is working with nature by using natural materials to take back areas.
However, hard engineering involves building man made structures to protect the coast or drainage basin.

Question 3

Explain what each hard engineering scheme is.

Answer 3

Flood walls- building high walls alongside a river to increase its capacity to prevent flooding
Levees- like flood walls but increases capacity even more as they are built at a distance
Dredging- increasing channel capacity to increase the speed of river
Flood relief- creating extra channels to divert excess water

Question 4

Explain what each soft engineering scheme is, how they work and the pros/cons

Answer 4

Flood plain retention- the level of flood plains is lowered and their surface restored to shrubs and grassland.
River channel restoration- meanders rebuilt lengthening river. Banks are lowered and hard engineering removed.
Afforestation- the planting of trees.