Flooding Flashcards
How does flooding happen?
Level of river gets so high it spills over its bank.
What is the name when a flood happens without warning?
Flash floods.
Rivers flood due to…
Physical factors.
Human factors.
River level increase when…
The discharge increases.
Name 4 physical factors that cause flooding
Prolonged rainfall.
Heavy rainfall.
Snowmelt.
Relief.
What happens after a long period of rainfall?
Soil becomes saturated.
If rainfall can’t infiltrate into the soil what happens?
Increased surface runoff into rivers.
What does heavy rainfall mean?
Lot of surface runoff.
A lot of surface run off means…
Increased amount of discharge quickly.
Snow or ice melts it means…
Lots of water goes into the river in a short space of time.
If a river is in a steep sided valley, what happens to the water?
Reach river channel faster as the water flows quicker on steeper slopes.
Name 2 way rivers flood because of human factors
Deforestation.
Building construction.
Trees intercept rainwater on their…
Leaves which then evaporates.
Tress take up…
Water from the ground and store it.
Cutting down trees increases…
Volume of water that reaches river channel.
