Rivers Flashcards
What is the course of a river?
The downhill flow of the river
What are the characteristics of the Upper Course?
Steep, V shaped Valley, Deep channel, Narrow Channel
What are the characteristics of the Upper Course?
Medium Gradient, Sloping Sides, Widening deepening channel
What are the characteristics of the Lower Course?
Wide channel, flat valley, deep channel
What is vertical erosion?
Deepens the valley and channel, scraping angular erosion
What is lateral erosion?
Widens the valley and channel, forms meanders
What is Hydraulic Action?
The force of the river colliding with rocks to break them
What is Abrasion?
Eroded rocks are picked up by the river and scrape against the channel
What is attrition?
Rocks crash into eachother, shattering into smaller fragments, the rocks round off
What is solution?
When rock is dissolved by river water
What is Traction?
When large boulders are forced across the river bed by water
What is saltation?
Pebbles are bounced off the river bed
What is suspension?
When small particles are suspended in water and carried by it
What is solution?
When materials are dissolved in water
What factors cause deposition?
- Water losing energy
- The volume of water falls
- There’s more eroded material and the water can’t carry it
- The water gets shallower
- The river reaches its mouth
How is a waterfall formed?
- Water flows over hard and soft rock
- Soft rock erodes by abrasion
- Creates a step
- Water flows over the step
- The waterfall undercuts the area under the step
- This causes the step to collapse
- The step falls and is swirled under the waterfall
- This erodes into a plunge pool
- Repeat! Causing Retreat