3. River Processes

Question 0

Define Hydraulic Action (form of erosion)

Answer 0

The force of the river against the banks can cause air to be trapped in cracks and crevices (narrow opening in the rock). The pressure weakens the banks and gradually wears it away.

Question 1

Define Erosion

Answer 1

The wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river.

Question 2

Define Abrasion (form of erosion)

Answer 2

Rocks carried along by the river wear down the river bed and banks.

Question 3

Define Attrition (form of erosion)

Answer 3

Rocks being carried by the river smash together and break into smaller, smoother and rounder particles.

Question 4

Define Solution (form of erosion)

Answer 4

Soluble particles are dissolved into the river.

Question 5

Define Solution (river transport process)

Answer 5

Minerals are dissolved in the water and carried along in solution.

Question 6

Define Suspension (river transport process)

Answer 6

Fine light material is carried along in the water.

Question 7

Define Saltation (river transport process)

Answer 7

Small pebbles and stones are bounced along the river bed.

Question 8

Define Traction (river transport process)

Answer 8

Large boulders and rocks are rolled along the river bed.

Question 9

What is Deposition?

Answer 9

When a river loses energy, it will drop or deposit some of the material it is carrying.

Deposition may take place when a river enters an area of shallow water or when the volume of water decreases - for example, after a flood or during times of drought.

Deposition is common towards the end of a river’s journey, at the mouth.

Deposition at the mouth of a river can form deltas - for example, the Mississippi Delta.