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What causes Flooding?
You know what a flood is …. ??? Don’t you??
Well, can you identify three ways a flood can be caused??
W.A.L.T???
“Today we are learning about the different ways flooding is caused”
W.I.L.F???
• listen and make notes during PowerPoint
• carefully craft some written work afterwards
• (think of special terms for our GeoBingo)
What causes Flooding?
The river has overtopped its banks and spilled onto the flood plain.
Exceptionally heavy rain
Boscastle, U.K.
summer 2004
= flash flood.
Flash Flood in a dry desert area (S.W. U.S.A.)
Heavy rain onto dry hard ground.
Snow Melt flood in Spring thaw.
e.g. The Yukon River in Alaska, U.S.A.
Monsoon wet season
Essential for rice growing
But bad if there is too much rain.
After a Dam Collapses:
Teton Dan USA. 1976Humans to blame
Los Angeles U.S.A.
Humans to Blame
As cities get bigger there is more impermeable concrete and tarmac. The rain can’t soak into the ground.
Nepal -deforestation
More people
More farmland needed
Trees cut down
Terraces made on hillsides
Landslides and more run-off
More risk of flooding
High Tides can cause the sea to flood the land in a storm surge.
Hurricanes cause storm surges too!
e.g. Florida U.S.A.
Tsunami Flooding
Submarine earthquakes cause giant tidal waves
e.g. S.E. Asia 2004
Cyclone hits Bangladesh
Bangladesh has monsoon river floods and cyclone sea floods. Coastal areas have some concrete shelters.
Tropical Islands threatened by sea level rise caused by Global Warming. e.g. The Maldives
GeoBingo1.
2.
3.
4.
5.
5.
6.
7.
8.
9.
10.
GeoBingo1. Flood plain
2. Boscastle
3. Flash flood
4. Snow melt
5. Los Angeles
5. impermeable
6. deforestation
7. Florida
8. Monsoon
9. wadi
10.storm surge