geog unit 5 lesson 1

1. Chong Boon Secondary School
Sec 2 Geography
Floods
Unit 5 Lesson 1
Types of floods

2. Inquiry
Question
How can cities
prepare for
floods?

3. Thinking Frame
What are
floods?
How do floods
affect people in
cities?
How should
cities prepare
for floods?
How should
cities prepare
for floods?
Flood
intervention

4. What are floods
• Sudden increase in surface
water.
• Drainage system unable to
cope.
• Large amounts of water
pooling on the surface.

5. Floods
• Can bring positive impacts
–Farmers farm on floodbanks
–Benefit from the river sediment
that collects after flooding
• Cities tend to face higher flood
risk.

6. Types of flood
1. Coastal Flood
2. River Flood
3. Flash Flood

7. Coastal Flood
• Occurs along the coast.
–Low-lying coastal areas (river mouths)
• River mouths are where the river
discharges into the sea.
• Caused by intense storms
–Tropical storms and cyclones
• Cyclones are also known as Hurricanes /
Typhoons

8. Coastal Flood
• Strong winds generate large waves –
Storm Surge
• Storm surges bring higher water
levels and cause coastal floods
• Tsunamis also cause coastal floods.

9. Coastal Flood

10. River Floods
• Sudden increase in river’s flow
(water)
• Water overflows the banks
• Tends to occur on floodplains, lower
course of the river.
• Leads to deposit of sediments on
floodplains
• Caused by snowmelt, heavy rainfall,
dam failure, etc.

11. River floods

12. Positive effect of river floods
• Sediments are rich in nutrients.
• Floodplains are good for crop
cultivation.
–Wet rice cultivation
• High risk of crop failure when there is
sudden flooding.

13. Floodplain Farming

14. Flash Floods
• Sudden floods, lasts for a short
duration.
• Caused by sudden and heavy
rainfall.
• Can also be caused by Coastal
and River floods.
• Cities tend to be badly affected
by flash floods.

15. Flash Flood

16. Summary
• What is a flood?
• What are the 3 main types of
floods?
• Which type of flood will affect
Singapore the most?

17. “Oh My Flooded Home!”

18. Group Work
In your groups,
• Take a look at the map and the
scenarios that you have been given.
• Discuss & Identify the type of flood
that each scenario is experiencing.
• Answer the questions on the A3
paper provided.

19. Resident in Town A
“The sky went dark suddenly and the rain was
incredible. I’ve never seen rain like that, so
intense and so heavy. It lasted for at least an
hour! Then the drains were overflowing. Within
20 minutes, the water was ankle deep and
another 10 minutes later it was already knee
deep at some parts of the city”

20. Resident in Town B
“It’s always like this during this time of the year.
It’s the monsoons, they bring the tropical
thunderstorms. Some crazy people still insist on
going out to sea for surfing! The storm surge is
normally not so bad but this year it stretched
right into the middle of town!
All the subway services were stopped, there was
water flooding in the tunnels!”

21. Resident in Town C
“Whenever it is spring, the snow on the
mountain top will melt. There is always this
sudden rush of water from the mountains. Some
years the water level rises and just overflows the
banks into the floodplains but this year it was
really bad.
A lot of the crops that were planted on the
floodplains were swept away by the strong
floodwaters. “

22. Town A
What type of flood was
experienced?
List 3 evidences that you found to
justify your choice.
You are the mayor of the town.
What are 3 things that you can do
to help the people in this Town?

23. Town B
What type of flood was
experienced?
List 3 evidences that you found to
justify your choice.
You are the mayor of the town.
What are 3 things that you can do
to help the people in this Town?

24. Town C
What type of flood was
experienced?
List 3 evidences that you found to
justify your choice.
You are the mayor of the town.
What are 3 things that you can do
to help the people in this Town?

25. Map of Taman Buaya
Mount Crocodile
Town C
Town B
Town A
Pacific Ocean