Levee Flashcards
Example
River Moy
River Rhine
Mississippi
What is a levee?
Wide range of sediment on the banks of a river.
Where are they found?
Lower stage of sediment laden rivers
When does river deposition occur?
When the river loses energy and can’t carry its load.
Why might the river lose energy?
when it floods into the flood plain and becomes shallower
Why do levees form?
Flooding
What happens during normal flow
It’s confined in its channel and deposition happens on the riverbed
What happens during flood events
The river overflows its channel and pours onto the floodplain
What happens after the river over flows its flood plain
It will slow down due to decrease in depth
And the fact that it has escaped its channel and has a wider area to flow over
What does the loss of energy cause
Deposition
What is deposited first
Heavier stones, closer to banks
Where does the alluvium go
Carried further away across flood plains
If repeated flood events
Heavy sediment builds up and form ridges (levees)
Levels are…
A rivers natural defence against flooding
Natural levee building + deposition on riverbed =
River channel above flood plain and levees are the only thing preventing it from flowing over
Raised river channel
