2.2 Rivers

Question 1

What are the types of erosion?

Answer 1

• Hydraulic action
• Attrition
• Corrosion
• Corrasion

Question 2

Hydraulic action

Answer 2

water and air getting into cracks in a rivers banks and bed causing erosion through increased pressure

Question 3

Attrition

Answer 3

load crashing into each other in a river

Question 4

Corrasion (abrasion)

Answer 4

the process of a rivers’ load crashing and rubbing into a rivers’ banks and bed causing pieces to break off

Question 5

Corrosion (solution)

Answer 5

the process of water dissolving a rivers’ load as well as its beds and banks

Question 6

What are the four types of transportation?

Answer 6

• traction
• saltation
• suspension
• solution

Question 7

Traction

Answer 7

the heaviest material is rolled, or dragged along the river bed

Question 8

Saltation

Answer 8

small rocks bounce/bump along the river bed

Question 9

Suspension

Answer 9

small particles (e.g. clay/silt) are carried by the river bed

Question 10

Solution

Answer 10

chemical load is carried in the water flow of the river

Question 11

Upper cross-section of a river

Answer 11

steep gradient
narrow valley
vertical erosion

Question 12

Middle cross-section of a river

Answer 12

V-shaped
less steep
lateral and vertical erosion

Question 13

Lower cross-section of a river

Answer 13

flatter land

very gentle

Question 14

Describe the formation of waterfalls

Answer 14

• soft rock erodes more quickly, under-cutting the hard rock
• the hard rock is left overhanging, because it isn’t supported, it collapses
• the fallen rocks crash into the plunge pool. they swirl around, causing erosion
• process is repeated, water moves upstream
• a steep sided gorge is formed as waterfall retreats

Question 15

Benefits + problems of waterfalls

Answer 15

benefits:
- beauty
- tourism
- jobs related to tourism

problems:
- danger from fast flowing water
- navigation
- problems of creating transport link
- overcrowding -> pollution

Question 16

Describe the formation of rapids

Answer 16

• sections of rough turbulent water
• normally in a river’s upper course
• formed when you get layers of hard and soft rocks
• erosion
• uneven rough turbulent water