What 3 directional erosions can occur? (Processes rivers)
Headward erosion
Vertical erosion
Lateral erosion
What is headward erosion? (Processes rivers)
- Makes the river longer
- Occurs near the source
- Throughflow and surface run off cause erosion at the valley head
What is vertical erosion? (Processes rivers)
- Deepens the river channel
- Occurs in the upper stages of the course
What is lateral erosion? (Processes rivers)
- Makes the river wider
- Occurs in the middle and lower stages of the course
What are the 5 erosions? (Processes rivers)
corrosion abrasion cavitation hydraulic action attrition
What is corrosion? (Processes rivers)
- Bedload is dissolved by chemical processes
- Carbon dioxide dissolves in water to form a weak acid which reacts with rocks
What is abrasion? (Processes rivers)
Bedload rubs and scrapes against the bed and banks to wear them down
What is cavitation? (Processes rivers)
- Air bubbles generated in turbulent flow
- Release shockwaves as they burst against the bed
What is hydraulic action? (Processes rivers)
Pressure of the water forces air between cracks in the bed and banks
What is attrition? (Processes rivers)
Particles and rocks are smashed against each other to make them smaller and rounder
What does the velocity of a river provide energy for? (Processes rivers)
To transport materials
How can load be transported? (Processes rivers)
Traction
Suspension
Solution
Saltation
