Changes in rivers and their valleys Flashcards
(11 cards)
What does the long profile of a river show?
Changes in the river gradient from the source to the mouth
The long profile typically has a concave shape.
Where is the source of a river usually located?
In an upland area
What are the characteristics of the upper course of a river?
- Shallow
- Steep valley sides
- Narrow
- Low velocity
- Large bedload
- Rough channel bed
- High levels of friction
- Vertical erosion
How does the gradient change from the upper course to the lower course of a river?
It decreases from steep in the upper course to almost flat in the lower course
What are the characteristics of the middle course of a river?
- Deeper than upper course channel
- Gentle valley sides
- Wider than upper course channel
- Greater velocity than upper course channel
- Material in river decreases in size
- Smoother channel bed
- Lower levels of friction than upper course channel
- Lateral erosion
What are the characteristics of the lower course of a river?
- Deeper than middle course channel
- Flat floodplains
- Wider than middle course channel
- Greater velocity than middle course channel (apart from as the river enters the mouth)
- Material carried mainly sediment and alluvium
- Smooth channel bed
- Lowest friction
- Deposition is dominant
What process is dominant in the lower course of a river?
Deposition
Fill in the blank: The cross profiles of a river are _______ from one bank to another.
cross-sections- like cutting a slice of a cake
True or False: The gradient in the middle course of a river is steeper than in the upper course.
False
What happens to the size of material in the river as it flows from the upper course to the lower course?
Material decreases in size
What is the velocity of the river like in the lower course compared to the middle course?
Greater velocity than the middle course channel (apart from as the river enters the mouth)
