REVISION AS CAMBRIDGE GEOGRAPHY: RIVERS - FLUVIAL EROSION.

1. AS GEOGRAPHY
HYDROLOGY
4 QUESTIONS
REVISION
FLUVIAL
EROSION

2. DEFINITION
Fluvial erosion is the wearing away and/or removal of material by the
action of moving water in a river channel.

3. QUESTION 1
What are the four main processes of fluvial erosion?

4. ANSWER
Abrasion, solution, attrition, hydraulic action.

5. QUESTION 2
Which of these processes does not erode the bed/banks of the channel?

6. ANSWER
Attrition – it causes the load to decrease in size.

7. QUESTION 3
Which two physical factors chiefly influence the rate at which a river
erodes?

8. ANSWER
Rock type and available river energy.

9. QUESTION 4
How do dams affect rates of fluvial erosion?

10. ANSWER
Because sediment is trapped behind the dam, the river has less load to
carry further downstream.
This gives it more available energy to erode and the channel is often
scoured as a result.

11. IMPORTANT
You need to appreciate the varying significance of the different
processes.
Solution may only be important on calcareous rocks such as limestone,
which contain calcium.
Hydraulic action, forcing air/water into cracks/joints on the bank/bed,
may only be significant in times of flood or when the flow is very
turbulent.