River Rejuvenation
Specification Focus:
GEOG1 – Process and impact
of rejuvenation – knick
points, waterfalls, river
terraces and incised
meanders.
Learning Objectives:
• To understand the
process of rejuvenation in
rivers and the landforms
associated with this.
•
To practice map skills
using an OS map
• To practice exam
technique on a past paper
question
River Rejuvenation
Causes of Rejuvenation
There are two causes of rejuvenation in rivers:
1) Eustatic Rejuvenation
 Caused by sea-level change related to the
amount of water in the oceans.
2) Isostatic Change
 Caused by sea-level change related to rise and
fall of the land.
These processes give the river more potential energy and
thus a greater capacity to
__________________________.
• 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 retreats
cutting
a lower valley
Fall in sea level
• 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 Bluffs
New floodplain forms
River Rejuvenation
Knickpoints
• A sudden break or irregularity in the gradient of the long profile
• Usually marked by rapids but may be sharply defined as a
waterfall
Knickpoint
River Terraces
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/riv
er-terraces/402.html
River Terraces
Large and small
scale river terraces
Incised Meanders
These are formed when a river cuts down into its bed and
deepens it’s meanders. There are 2 types of incised meander:
Entrenched
Ingrown
Entrenched Meanders
Ingrown Meanders
Another cause:
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.
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
QUESTION
What is the symbol for a
rock outcrop and a cliff on
an OS map?
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.
What could I be asked in the EXAM?
Describe and explain the formation of channel features that can be
created by the process of river rejuvenation (15 marks)
• Start off by writing a short plan of how you would answer the question. You
can do this as a mind map or bullet points.
• Then try writing out your answer in full. It should take you no longer that 15
minutes.
• Once you’ve finished, swap your answer with someone else and use the mark
scheme to give them a mark. Also give them 2 comments:
 what they have done well
 what they could do to improve