1. Floods occur when large amounts of water overflow onto normally dry land. There are three main types: coastal floods, river floods, and flash floods. 2. Coastal floods occur along coastal areas due to storms, tropical cyclones, or storm surges. River floods happen when water in a river rises and overflows its banks onto the floodplain. Flash floods can rise suddenly due to heavy rainfall. 3. Videos showed examples of each type: the 2011 Japan earthquake/tsunami caused a coastal flood, flooding along the Mississippi River in the US was a river flood, and heavy rain in Colorado resulted in a flash flood. Being able to identify the cause and location is key to determining the flood type

1. Floods: What are floods?

2. What are Floods?
Floods : How Can Cities Prepare For Floods?2
‘Floods are overflows of large amounts of water onto
land that is normally dry.’

3. Have anyone of you experienced
the Orchard Road flooding in 2011/
flooding?
Do you think Yew Tee will
be flooded?

4. Why is it important to learn about floods?

5. Number of
events
Flood events in Singapore
1 Bukit Timah Canal overflowed on 19 November 2009
2 Orchard Road flooding 16 June 2010
3 Orchard Road flooding 23 December 2011
4 Western parts of Singapore 5 September 2013
Why is it important to learn about floods?

6.  Describe the types of floods
 Coastal floods
 River floods
 Flash floods
Lesson Objective

7. Types of Floods
Coastal Floods River Floods Flash Floods

8. Coastal Floods
 Definition:
Coastal floods occur
in areas along the
coast (especially low-
lying coastal land,
such as river
mouths)
Floods: How Can Cities Prepare For Floods?
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9. River floods
Definition:
River floods occur when water in the river rises and
overflows its banks
Floods: How Can Cities Prepare For Floods?
9 A cross-section of a river channel

10. River floods
River floods occur on the floodplain, which consists of the river
and the low-lying land on either side of it
Levees: Raised banks on both sides of the river.
Floods: How Can Cities Prepare For Floods?
10 A cross-section of a river channel

11. Flash floods
Definition:
A flash flood can be
recognised by its quick
rise in water level.
It can take place
suddenly and lasts for a
short period of time
Floods: How Can Cities Prepare For Floods?
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12. 1. Great Tohoku Earthquake and Tsunami that hit Japan in 2011
caused a coastal flood in Miyako City
2. Mississippi River, USA 2011
3. Flash flood in Colorado, USA, September 2013
Video

13. Great Tohoku Earthquake and Tsunami 2011
 Play video from the start to 1.08minutes.

14. 1. From the video, what is Japan experiencing?
 Earthquakes and Tsunami.
2. What is the cause of the coastal flooding?
 Tsunami
3. How do we know if it is a coastal flooding?
 The tsunami is approaching the coast.
 We can observe that the ships and boats are drawn away by the
water.
Questions from worksheet 5.1A

15.  River flood: Play video from the start to 0.13minutes, then start
at 0.39minutes to the end(2.26).
 The video shows an aerial view of the Mississippi river, the
image was taken by Landsat 5 (satellite).
 Show the outline of the river (in dotted lines)
 State what is the cause of the river flood.
 Observed the contrast between the non-flooded areas and
flooded areas. (Pause at 0.59, 1.22, 2.01, 2.05, 2.19)
 Observed that the crops are being inundated.
Mississippi River, USA 2011

16. 1. What causes river flooding?
 Heavy spring rains/heavy rainfall
 Snowmelt
2. How do we know if it is a river flood?
 The flood occurred along the Mississippi River.
 Water overflow out of the banks.
Questions from worksheet 5.1A

17.  Flash flood: Play video from the start to 1.58 minutes.
Flash flood in Colorado, USA, September 2013

18. 1. What weather is Colorado facing? (Circle the answer)
 Extreme weather – Wet or Dry.
 (Large or Small) amount of rain expected.
2. What is the cause the flash floods?
 Extreme weather/ Heavy rainfall
3. How do we know if it is a flash flood? (0.30minutes)
 Spike in the river gauge, in less than ____15_____ minutes, __10___
feet of water slamming down.
Questions from worksheet 5.1A

19. Other possible causes for
floods

20. Coastal Floods
 Other possible causes:
 Intense storms such as
tropical storms and tropical
cyclones. Tropical cyclones
are also known as
typhoons and hurricanes.
 Storm Surges
Floods: How Can Cities Prepare For Floods?
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21. River floods
 Other possible
causes:
Dam failure
Floods: How Can Cities Prepare For Floods?
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22. Flash floods
 Other possible causes:
 Coastal and river floods
Floods: How Can Cities Prepare For Floods?
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23. Workbook Activity 5.1 Page 117 & 118
Describe the types of flood.
Identify the flood type
Give evidence
Practice Time!

24. Types of Floods
Coastal Floods River Floods Flash Floods
Recap