River processes

Question 1

Erosion: Corrasion (abrasion)

Answer 1

Sand and pebbles dragged along river bed, wearing it away.

Question 2

Erosion: Hydraulic action

Answer 2

Fast-flowing water forced into cracks, breaking bank up over time.

Question 3

Erosion: Attrition

Answer 3

Rocks + stones knock together, wearing each other away.

Smaller + rounder

Question 4

Erosion: Solution

Answer 4

Rocks (eg: limestone) dissolved in acid water.

Question 5

What are the “river’s load”?

Answer 5

Boulders, pebbles, sand, silt and mud being transported.

Question 6

Transportation: Saltation

Answer 6

“skipping” motion

Smaller stones + pebbles picked up then dropped again.

Question 7

Transportation: Solution

Answer 7

Dissolved chemicals are carried in solution, invisible to the eyes.

Question 8

Transportation: Traction

Answer 8

Large stones are dragged along the river bed.

Question 9

Transportation: Suspension

Answer 9

Tiny particles of sediment carried in the river’s current.

Question 10

What is “bedload”?

Answer 10

Heavier material carried along the river bed.

Question 11

Deposition occurs when a river loses velocity (energy). What can cause this?

Answer 11

• decrease in gradient
• decrease in discharge as water drains away after heavy rain
• river meeting the sea or a lake, forming a delta
• river flowing more slowly on the inside of bends

Question 12

What is discharge?

Answer 12

The volume of water flowing down the river at any time.

Question 13

What is discharge measured in?

Answer 13

Cubic metres/second - cumecs

Question 14

In which climate can the discharge vary considerably?

Answer 14

Wet + dry seasons

Affected by melting snow in spring