1. River Processes
Erosion, transportation and
deposition

2. 1. Erosion

3. 1) Processes of river erosion (p100)
Hydraulic action
Abrasion
Attrition
Solution

4. Hydraulic Action
The sheer force of water hitting the bed and banks. Most
effective when large volumes of water are moving fast
Abrasion
This is the process by which the bed and banks are worn down by the
river’s load. The river throws these particles against the bed and
banks, sometimes at high velocity.
Attrition
The load in the river repeatedly hits the river bed and banks,
causing material to break off.
Solution
This is the chemical action of river water. The acids in the water
slowly dissolve the bed and the banks.
Processes of river erosion

5. Vertical and Lateral erosion
• Vertical erosion
– This is when the river cuts down vertically into the
ground to create a V shaped valley. It is normally
in the upper course.
• Lateral erosion
– This is when the river erodes out laterally, across
the valley, creating a flat valley bottom. It is
normally in the lower course.

6. Vertical erosion creating a V shape

7. Lateral erosion creating a wide flat
valley

8. 2. Transportation

9. How is material transported downstream? (p100)
Saltation
Solution
Traction
Suspension

10. 3. Deposition

11. 3) Deposition
• When a river reaches its mouth the energy
levels drop. As a result any material that has
been carried by the river is deposited in an
orderly fashion.
• Normally the bigger, heavier particles are
deposited first as the river doesn’t have
enough energy to carry them any further
while the lighter, smaller particles are
dropped last.

12. 3. Deposition

13. Ganges Delta

14. Long River Profile (p102)

16. Upper

17. Middle course

18. Video 1 and 2Lower course

19. Your Turn
• Choose one of the processes (erosion, transportation or
deposition) and produce a poem or a recipe about that
process!
Example poem:
Erosion wears the river banks away,
The rocks are so brittle they easily
fray.
Always flowing and carrying the
load,
Hydraulic action causes the rocks to
almost explode!
Example recipe:
Ingredients: ………….
Erosion: Take soluble
minerals as river flows and
dissolve them to make
solution
Transportation: Pick up a
handful of rocks and throw
them so they skip along the
river bed