L.O.s
1.To understand what river rejuvenation is and the landforms that result from it
2.To practice cartographic skills using an OS map extract
1
1

What are the 10 landforms we learnt last lesson and which processes are they formed by?
Landforms of
EROSION
Landforms of EROSION and DEPOSITION
Landforms of
DEPOSITION
Waterfalls,
Rapids and
Gorges
Potholes
Oxbow lakes
Meanders
Floodplains
Braided channels
Levees
Deltas

• A river can be rejuvenated in two ways
1) Sea-level change
 This could be due to a fall in sea level OR a rise in land level
2) River capture
 All rivers tend to cut back towards their source by headward erosion. Sometimes the river may cut into an adjacent river valley and join up with the tributaries of another river.
These processes give the river more potential energy and thus a greater capacity to ____________.

Rejuvenation by Sea-level Change
• If sea level falls (or land rises) the river adjusts to its new base level, firstly in the lower reaches, and then progressively inland.

Rejuvenation by Sea-level Change
• If sea level falls (or land rises) the river adjusts to its new base level, firstly in the lower reaches, and then progressively inland.
____________ retreats cutting a lower valley
Fall in sea level

Rejuvenation by Sea-level Change
• If sea level falls (or land rises) the river adjusts to its new base level, firstly in the lower reaches, and then progressively inland.
River___________
Waterfall decreases in size to form ________
New ______________ forms

• As the river adjusts a number of landforms may be created
 Knick points
 River Terraces
 Incised Meanders

• A sudden break or irregularity in the gradient of the long profile
• Usually marked by rapids but may be sharply defined as a waterfall

River terraces are remnants of old river floodplains left at higher levels after a river down cuts due to rejuvenation
Several terraces may be left if rejuvenation occurs more than once http://www.bbc.co.uk/learningzone/ clips/river-terraces/402.html

Large and small scale river terraces

These are formed when a river cuts down into its bed and deepens it’s meanders. There are 2 types of incised meander:
Entrenc hed
Ingrow n

Case Study the River Rheidol, Ceredigion

Case Study the River Rheidol, Ceredigion

Case Study the River Rheidol, Ceredigion

Case Study the River
Rheidol, Ceredigion

Case Study the River Rheidol, Ceredigion

Case Study the River Rheidol, Ceredigion
TASK
Practice your cartographic skills by completing the worksheet on the
River Rheidol
EXTENSION: Locate grid square 7579. This is an excellent example of an incised meander. Draw an enlarged version of this grid square to show the main features of the meander. Mark on some contours to indicate how the meander has become a winding gorge. Add labels to describe the main features.

L.O.s
1.To understand what river rejuvenation is and the landforms that result from it
2.To practice cartographic skills using an OS map extract
3. To practice exam technique by answering and marking a past paper question
On the paper provided write down:
• One thing you have learnt today.
• One thing you found difficult
Write your name on the paper, fold it up and hand it to your teacher before you leave