1. The Middle and Lower Course of a River

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3. How is material transported downstream?
Traction
Saltation
Suspension
Solution

4. How is material transported downstream?

5. What landforms are found in the middle and lower course?
Meanders
Oxbow Lakes
Floodplains and Leveés
Deltas

6. The Rhône – lower and middle course
Geneva
Genissiat
Source of the Rhone 200km
in the Swiss Alps
Lyon
Massif Central
Alps
Beauchastel
Donzere
Caderousse
Avignon
The Camargue
Mediterranean Sea
HEP station

7. The Rhône at Avignon
The ‘Pont d’Avignon’ does not stretch across the Rhone anymore…some of the arches were destroyed in a flood.

8. The Rhône The Côte du Rhône……
the lower course of the Rhone Valley is famous for its vineyards

9. The Rhône – hydrographs
Hydrograph of the Durance (a tributary of the Rhone)
Study the hydrograph and the map of the Durance.
Describe how the discharge varies throughout the year.
Explain these variations in discharge incorporating the following terms:
evapotranspiration snowfall source

10. The Rhône – tributaries
How have these tributaries contributed to the unpredictable flooding of the Rhône?
Alps
Isere
Massif
Central
Drome
Ardêche
Durance

11. The Rhône The problems:
Flood markings at Caderousse
The problems:
1) For several centuries, the inhabitants of the Rhone suffered many floods.
2) In addition, there were water shortages due to the seasonal variations in the flow of water.
3) There was also an increasing need for energy in the 1950s and 1960s.
How do you think they solved these problems?

12. How was the Rhône tamed?
Solution : Large dams were built by the Compagnie Nationale du Rhone from the late 1930s. For example, the Genissiat Dam was started in 1937.
These dams are multi-purpose schemes.
They hold back the spring melt water and so stop the floods.
They release this water in the dry summer to irrigate the intensive fruit and vegetable growing areas and the many vineyards on the slopes of the Rhone valley. The water is also used for cooling in the two, nuclear power plants near Genissiat – Beugy and Creys-Malville.
In addition, the dams produce HEP (Hydroelectric Power). The whole French Rhone produces over 16 million MW (compared to 65 million MW produced by all French HEP plants).

13. Revetments on the Rhône near Caderousse
How do these revetments prevent flooding in this part of the Rhone?
marker measuring discharge

14. The Rhône near Caderousse
Old course of the Rhone near Caderousse

15. Dams on the Rhône
This is a dam generating HEP near Beauchastel.

16. Dams on the Rhône The dams generate HEP which….
HEP generated near Donzere
provide the power to run the TGV in the Rhône valley.

17. (tributary of the Rhone)
The Rhône – deposition
A river deposits all or some of its load when there is too much material to carry. This is likely to happen when extra material is added into the river and/or when the river loses velocity. If this happens before the river reaches its mouth, braiding can occur. This simply means that the river splits into two or more channels due to the deposition. The ‘islands’ formed are called eyots or ayots.
braiding in the
River Ouveze
(tributary of the Rhone)

18. Meander = a bend in a river

19. Oxbow lakes

20. Oxbow lakes new course of the river Meander neck becomes smaller
When the river floods it breaks through the thin meander neck and the river takes the easier, straight course. This leaves the meander loop ‘cut off’ as an oxbow lake. Over time, the oxbow lake will become colonised by vegetation.
new course of the river
Meander neck becomes smaller
oxbow lake

21. The Rhône near Caderousse
This was an old meander loop of the Rhone.
The meander loop was deliberately ‘cut off’ to straighten the river. Why do you think this happened?

23. Floodplains

24. Floodplain formation
Floodplains and levees are formed by deposition in times of river flood. The river’s load is composed of different sized particles. When a river floods it deposits the heaviest of these particles first. The larger particles, often pebble-sized, form the leveés. The sands, silts and clays are similarly sorted with the sands being deposited next, then the silts and finally the lightest clays. This deposition makes up the floodplain.

25. The Rhône – floodplain The large pebbles absorb the heat of the sun.
Orchard
Old floodplain of the Rhone …
The large pebbles absorb the heat of the sun.
How do you think the pebbles got to be here?

26. Delta formation silt clay sand
Annotate the delta with the following labels:
Delta formation
silt
clay
sand
Delta are found at the mouth of a river, where the river meets the sea. At this point the river is carrying too much load for its velocity and so deposition occurs.
The top of the delta is a fairly flat surface. This is where the coarsest river load is dropped. The finer particles are carried into deeper water. The silt is dropped to form a steep slope on the edge of the delta while the clay stays in suspension until it reaches the deeper water.

27. The mouth of the Rhône The ‘Grand Rhone’ Petit Rhone Grand Rhone
Mediterranean Sea

28. The Rhône’s delta – the Camargue
The area of the Rhône’s delta is known as the Camargue. The Rhône’s delta is an example of an arcuate or fan delta. This delta, home to nine thousand people, has grown so large mainly due to vast amounts of sediment that the Rhône has deposited over the years and the low tidal range of the Mediterranean.

29. The Rhône’s delta – the Camargue
Most of people that live in the Camargue are farmers. Rice, fruit and vines are grown, especially in the northern part of the delta. Nevertheless, most of the delta is infertile and only used for cattle and horses.
The Camargue also attracts over 1 million tourists mainly due to its status as an important wildfowl reserve (designated Regional Nature Park in 1970). Wild boars, horses, geese and even pink flamingos are found here!

30. The Rhône’s delta – the Camargue
There is also heavy industry in the Camargue. It is situated at the mouth of the Rhone. Look at the photo below. It shows oil refineries near Port St Louis.
What are the advantages of this site for industry?
Why do deltas attract heavy industry, such as oil refineries, rather than light industry?
The Camargue
Port St Louis
Mediterranean Sea

31. Questions

32. The drag and drop activity follows the animation

33. Meander bend on the River Conwy
Explain why there is more deposition at ‘A’ rather than at ‘B’.

34. Sketch this plan view of a meander bend and label the line of highest velocity.

35. Draw the following four diagrams in the correct order of oxbow lake formation. Match 3 of the diagrams with the most appropriate explanation from ‘A’, ‘B’ and ‘C’. 4. 3. 2.
X = erosion on the outside of the meander bend 1. X X X X X
A. The river floods and erodes through the thin meander neck. The river now takes the easier, straight course. The meander loop is left as an oxbow lake.
B. The river meanders. The fastest flow is therefore on the outside of the bend. This fast current erodes the meander neck through the processes of erosion.
C. The meander neck is further eroded until only a thin piece of land separates the two channels.

36. Name the river landform shown in this aerial photograph.
What else can you identify?
How can you tell that this is not the Upper Course of a river?

37. This is a cross section of a floodplain.
Draw a simple sketch of the diagram and annotate with the following labels:
leveés
clays and silts
sands

38. The River Conwy has deposited material in this section of its course
The River Conwy has deposited material in this section of its course. Suggest reasons why this has happened.

39. This is a cross section of a meander bend
This is a cross section of a meander bend. Sketch the diagram and mark on the following:
river cliff
fastest velocity
slip off slope
undercutting
area of deposition

41. Landforms are primarily caused by:
processes of erosion
processes of deposition
a mixture of erosion and deposition
Which of the following landforms are the result of a mixture of erosion and deposition?
deltas
meanders
floodplains
waterfalls
leveés
oxbow lakes
rapids
v-shaped valleys
interlocking spurs

42. Write a list of land uses in the middle and lower course of the Rhone (use place names where possible).
How does the land use of the lower course of a river contrast with the upper course?