1. River landscapes and processes
Geography CCEA GCSE 2009

2. The earth’s crust is modified by fluvial processes which result in distinctive landforms

3. River Structure

4. Stages in the Development of a River Valley

5. The river cuts downward to
form a ‘V’shaped
valley.
The river starts
to meander

6. What happens next?

7. River uses its meanders to cut from side
to side eating into
the valley
Floodplain
starts to
form 1 2

8. What happens next?

9. 1 2

10. What happens next?

11. Floodplain
River bluffs
Alluvial
deposits
River cliff

12. River Processes
A river process is something that happens in the river. The main processes in the river are
Erosion - where parts of the river bed and bank get eroded / removed from the landscape
Transportation - where the eroded material is carried from one place to another through the river system
Deposition - where the river load becomes too heavy for the river to carry and is dumped down / deposited.

13. A river can erode material from its bed and banks in 4 main ways
Abrasion – Moving water throws particles it is carrying against the bed and banks of the river which dislodges more material
Hydraulic Action - The sheer force of the water pounding into the bed and banks can dislodge material
Attrition - Particles being carried downstream knock against each other, wearing each other down. This results in smaller, rounder particles as you move downstream
Use your text book to see if you can find the 4th type!

14. Methods of Erosion
Abrasion –
Hydraulic Action -
Attrition -
Solution-

15. Methods of Transportation
Rivers transport material in 4 main ways
Solution - Some minerals (particularly in limestone areas) dissolve easily in water and are not visible to the naked eye
Suspension – As the speed or velocity of a river increases, it is able to pick up and carry larger and larger particles in its flow. Where particles are carried along in the flow and are not in contact with the river bed, they are said to be travelling in suspension.

16. Methods of Transportation
Saltation - Heavier particles may not be held in the flow all the time but may be bounced along the bed
Traction - The heaviest particles are rolled along the bed. Such particles may only be moved when the river has a large volume of water in it

17. Methods of Transportation
Solution -
Suspension-
Saltation -
Traction -

18. solution

19. River Features
Rivers are eroding, transporting and depositing constantly within the drainage basin system.
The river can be divided into 3 sections – Upper Course at the Source, Middle Course and Lower Course at the Mouth of the river. The river displays different characterisitics at each section

20. How to take notes on each of the River Features!
Course: Upper / Middle / Lower
Feature: Eg Waterfall
Diagram to illustrate: (make sure that this is labelled!)
Notes to explain how the feature happens:
Example of this feature:
Make sure that you take a new page for each new feature!

21. The V - Shaped Valley

22. Can you mark the V-shaped valley’s on these photos?

29. http://www. school-portal. co. uk/GroupDownloadFile. asp

30. How are V-shaped valleys formed ?

31. Why does it erode downwards?
How does it erode downwards?

35. Use this sketch to help explain how they form
Vertical abrasion

37. Upper Course Interlocking Spurs
Also known as ‘Torrent’ or ‘Youth’ stages
Interlocking Spurs
In the Upper Course, the river is fast flowing, but there is little water and load. The river is often called a stream and does not have the erosive power to remove the hillsides (spurs), but erodes downwards instead.
EROSION TYPE: Vertical and Headward

39. Waterfalls and Gorges

40. Draw the stages in the formation of a waterfall
Explain in as much detail what is happening at 3
3. What is happening here? (see next slide)

41. Waterfall formation flash

44. Case study:
Niagara Falls
USA
Canada

45. USA
Canada

46. Canada Horseshoe
750 meters

47. 52 meters high

48. American Bridal Falls
330 meters

49. Both falls…the falls help to produce HEP

50. The falls erode back at a rate of 1.5 meters a year

51. Frozen Falls

52. 20 million visit the falls every year
Visitors !!!

54. The Falls were stopped in 1969 to see if debris could be removed to improve the look !!

55. Hard Resistant Rock - Limestone
52 meters
Weak Rock - Shale

56. Gorges (Upper & Middle Course)
Case study: Niagara Falls (USA and Canada)

57. http://www. school-portal. co. uk/GroupDownloadFile. asp

61. Upper Course Waterfall and Gorge 1 EROSION TYPE: Vertical and Headward
(OBLIQUE AERIAL VIEW)
EROSION TYPE: Vertical and Headward

62. Upper Course Waterfall and Gorge 2 EROSION TYPE: Vertical and Headward
(PROFILE VIEW)
EROSION TYPE: Vertical and Headward

63. Use the Niagara Falls Pictures PowerPoint
Notes to be taken from Page 10 from the Green Connections books

64. Meanders

65. 1. Can you mark the fastest flow on this?
2. What type of erosion do you think is happening?

67. ..can you mark on this the fastest flow?
What is a meander?
..can you mark on this the fastest flow?

68. … where do you think erosion would take place?
What is a meander
… where do you think erosion would take place?

69. Can you draw a cross section x-y?
What is a meander?
Can you draw a cross section x-y?

70. … this is what a cross section through a meander looks like
What is a meander?
… this is what a cross section through a meander looks like

71. Middle Course Meanders 1 Also known as the ‘Mature’ stage
(Aerial View)
Meanders are formed because the current swings to the outside of a bend and concentrates the erosion there. Deposition occurs on the inside of the bed where there is not enough energy to carry load.
EROSION TYPE: Lateral

72. Middle Course Meanders 2 EROSION TYPE: Lateral
(Profile View / Cross Section X - Y)
EROSION TYPE: Lateral
This cross section clearly shows the eddy current (near ’X’) formed by the velocity of the river being concentrated on the outside of the bend. These UNDERCUT the bank causing the formation of a RIVER CLIFF. On the inside (NEAR ‘Y’), a SLIP-OFF-SLOPE is formed where current is too slow to carry any load.

73. … this is what a cross section through a meander looks like
What is a meander?
… this is what a cross section through a meander looks like

74. Ox- Bow Lakes (Middle Course)

76. Can you annotate this photo graph ?

77. Can you annotate this photo graph ?

78. Can you annotate this photo graph ?

79. Can you annotate this photo graph ?

80. What are Flood Plains and levees?
                             
Levees
Floodplain

81. …. What do you think might happen here?
What is Meander Migration
…. What do you think might happen here?

82. What is Meander Migration

83. Middle Course Ox-Bow Lake 1 EROSION TYPE: Lateral
(Aerial View)
Ox-bow lakes are formed when two meander RIVER CLIFFS are being eroded towards each other. These will eventually meet, causing the river to then flow across the bottom of the diagram.
EROSION TYPE: Lateral

84. Ox-Bow Lake 2 (Aerial View)
Middle Course
Ox-Bow Lake 2 (Aerial View)

85. Levees

86. Leeves
River

87. Leveés and Raised Beds 1 (Front View)
Lower Course
Leveés and Raised Beds 1 (Front View)
DEPOSITION FEATURE: no erosion in the Lower Course
Leveés are formed when rivers flood. The river water overflows the banks of the river and immediately slows down due to friction with the FLOODPLAIN. This drops the larger particles first, building up a raised river bank called a LEVEÉ.

88. Leveés and Raised Beds 2 (Front View)
Lower Course
Leveés and Raised Beds 2 (Front View)
DEPOSITION FEATURE: no erosion in the Lower Course
Raised beds form in the Summer months when the river volume and energy are low and load is dropped onto the river bed. The bed raises up and the capacity of the river reduces, causing flooding in the winter. This in turn builds up the leveés and the whole process raises up the level of the river in the landscape.

89. Braided Channels (Oblique Side View)
Lower Course
Braided Channels (Oblique Side View)
DEPOSITION FEATURE: no erosion in the Lower Course
In the Summer months, load is dropped by the low volume of low-energy water in the river. These build up to form obstructions in the river and it divides up to flow around them. In the winter, it is likely that the river volume will increase and remove these obstructions.

90. Deltas

91. Lower Course Delta (Aerial View)
This deposition feature is one of the largest. When the flowing river hits the non-flowing sea, energy is suddenly lost. This causes all of the load in the river to drop in the river MOUTH. This builds up over time to create a delta – an area of land. The river divides into DISTRIBUTARIES to continue to the sea, which is now some way away from its original meeting point.

93. What's the Point of all This?
Can you work out what the river is trying to do by using this diagram?

97. River Structure

98. What's the Point of all This?
Can you work out what the river is trying to do by using this diagram?