1. Learning objectives Processes of River Transportation
River Profiles : Long Profile
River Profiles : Cross Profile
Fluvial Landforms
River Abstraction / Stream Piracy.
Learning objectives

2. Fluvial Landforms Waterfalls
Forms when resistant layer of rock prevents vertical erosion
Softer underlying layers are eroded
Resistant layer is undermined and collapses.
Waterfall retreats upstream.
Forms a Gorge or Ravine.

4. High Force waterfall, R. Tees
Waterfalls create a gorge upstream as they recede, This is a steep sided valley with no floodplain.

5. 6
An overhang develops where the softer rock below is eroded. In time this will collapse.
plunge pool
relatively softer rock
a band of hard rock interrupts the river’s course

6. Victoria Falls

7. Rapids in the Upper Tees Valley

8. FLOODPLAIN Flat areas next to rivers Lower course
During flooding – velocity is slower due to friction
Silt is deposited by the flood
Increases fertility of floodplain

9. FLOOD PLAIN
River Landforms

10. Fluvial Landforms Levees Form on the floodplain on the lower course
Flooding causes overflowing of banks
Heavier deposits occur repeatedly on the banks
Deposits are built up to raised banks known as levees
May be artificially raised and strengthened as flood protection
Swamps may form on the floodplain

11. Formation

12. Fluvial Landforms Meanders / Ox-bow Lake River reaches flat land
Begins to meander
Velocity is highest on the outer bend erosion – undercut bank – river cliff
Velocity is lower on the inside bend deposition – slip-off slope – gradual slope.

13. On the outside of the meander water is flowing more quickly
On the outside of the meander water is flowing more quickly. This results in erosion and the formation of a undercut slope or river cliff.
On the inside of the meander water is flowing more slowly. This results in deposition and the formation of the slip-off slope or river beach.

14. CROSS PROFILE ROUND A BENDY X X Y
Undercut
Erosion
Faster flow
Deposition
Slower flow
Slipoff

15. McKenzie River meanders and glacial lakes

16. Ox Bow Lake Formation

17. Ox Bow lake on Mississippi

18. F L A T LOWER COURSE OF A RIVER BRAIDED STREAM M O U T H MARSH
SANDBANKS
MEANDERS

19. Braided stream
The velocity of the river is reduced and this causes the river to split and rejoin many times
The river flows over loose sandy alluvium
An example of a Braided stream is the Orange river between Upington and Augrabies Falls.
As a result of the wide channel, the river flows slowly and large deposits of alluvium form islands in the middle of the river.

20. Braided River

21. Braided River, Shyok River, India

22. The Aswan Dam and the Nile Delta
Fluvial Landforms
The Aswan Dam and the Nile Delta
Deltas
When a river enters the sea or a lake the gradient is gentle and the flow speed of the river is reduced resulting in the deposition of sediments causing the river channel to become blocked.
Requirements for a Delta to form
A large and constant supply of silt.
A slow flowing river with water all year
No strong tidal effect in the sea
A calm, shallow sea with

23. Development of Delta