1. Middle Course Landforms- Floodplains and levees Flashcards
What time period are floodplain and river landforms formed over?
Different time scales from just days to thousands of years
What is deposition?
The release of load caused by a drop in energy
What are bluffs?
Raised hills that mark the furthest point of the floodplain
Define floodplain.
An area of flat land at the sides of the river caused by erosion and deposition
What are levées?
Raised embankments formed by deposition found on the banks of the river
What does competence refer to in river systems?
The maximum size of load a river can transport
What is friction in the context of river dynamics?
A contact force acting against the river that takes energy from the river
What is a meander?
A snake-like loop or bend in the river channel found in the middle and lower course
What happens to the river channel as it moves downstream?
The river channel flattens and floodplains form
What is the composition of floodplains?
Flat areas of land made from alluvium deposits
How are bluffs related to floodplains?
They mark the edge of the floodplain with rising slopes on either side
What type of erosion occurs in the middle course of a river?
Lateral erosion rather than vertical erosion
What contributes to the lateral erosion of a river channel?
The increasing quantity of water in the channel further downstream
What is the frequency of floods for unregulated rivers?
Every two to three years
What is deposited across the floodplain during flooding?
Alluvium
What happens when river water comes in contact with vegetation on the floodplain?
It loses energy due to friction and competence falls
What is the result of repeated floods on the banks of the river?
Formation of raised embankments called levées
What causes the competence of a river to transport larger gravels to fall?
An immediate fall in energy during flooding
Fill in the blank: Fine sediments held in suspension can be transported across the _______.
Floodplain
True or False: Levées are formed only during a single flood event.
False
