Lower Course Of A River Flashcards
What are the characteristics of a lower course of a river?
The river is wider, deeper, it meanders.
What are the characteristics of a valley in the lower course
It is flat and wide
What is a floodplain?
It is an area of land which is flat and floods often
Why are floods good for a floodplain?
It carries silt onto the surface which makes the soil fertile
Why is deposition common in the lower course of a river?
As the river has lost its energy.
What is a levee?
It is a natural embankment that can be strengthened by humans
How is a levee formed?
It is formed when a large amount of heavy material is deposited on the bank of a river.
What is a flood?
When a river has too much water in it so it spills out onto the land.
What causes flooding naturally?
When snow melts, rain is heavy or is long
What human activities cause flooding?
Deforestation and Urbanisation
How do trees help stop floods?
They catch water in their leaves and the roots soak up water.
What do roads do to contribute to flooding?
It stops the water from infiltrating the ground, and makes it gather in puddles, which build up.
How are drains causing floods?
They carry water to the river too quickly, overflowing it.
What are floods good for?
It fertilises the soil, flushes out pollution and makes breeding grounds for fish and prawns.
How are floods bad?
They destroy property, drown people and animals, contaminate drinking water, disrupt transportation and ruin crops.
How can a flood be prevented? (Hard Engineering)
Dredging the river to make it wider
How can floods be prevented? (Soft Engineering)
Plant trees to intercept water.
What can be built around a river to stop it from flooding?
Flood embankments, Flood Relief Channels
What is a flash flood?
A flood that comes without warning
Give an example of a flood
Biescas, Spain: 87 dead, 200 missing (August 1996)
Hard engineering
Human engineering to stop flooding, bad for the environment
Soft Engineering
Natural engineering, good for the environment
