Vincent Raeburn Linlithgow Academy
Malcolm McDonald Bathgate Academy Linlithgow Academy
How rivers transport
How rivers erode
 HYDRAULIC ACTION The force of the
water weakens and breaks up the rocks
Traction
Suspension
Rolling stones along the river
bed.( needs lots of energy)
 ABRASION The material carried in the
river wears away the river bed
Clay sized particles are carried
along by the river flow
river flow
 ATTRITION As the pebbles carried by
the river crash into each other,they
become smaller and rounder
 SOLUTION
The water in the river
dissolves the minerals in the rocks
River Basin
Source of River Aye
Watershed of River Aye
(boundary between basins)
Saltation
Solution
Sand sized particles
bounce along the river bed
Some minerals are dissolved
by the river water
Source
of river
Upper
Course
Middle
Course
Tributary
of River Aye
Lower
Course
Confluence
of River Aye
and tributary
Estuary of
River Aye
Flood plain
Mouth of
River Aye
Sea
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Formation of a waterfall
FEATURES OF THE UPPER COURSE
V-SHAPED VALLEYS WITH
INTERLOCKING SPURS
Waterfall
Retreats upstream
Hard rock
WATERFALLS AND RAPIDS
Soft rock
POT HOLES ON RIVER BED
Steep sides
( gorge )
Undercutting
The
The overhang
process
erodes
the
Eventually
Vertical
erosion
starts
again
softer rock
collapses
Forms
plunge
pool
forming an overhang
Eroded rock
WATERFALL
RETREATS . UPSTREAM
.
. .
The River Avon has smoothed
off parts of this hard
igneous rock. . .
OVERHANG
PLUNGE
POOL
UNDERCUTTING
OF SOFT ROCK
What is this process called?
MEANDERS
Meanders
MEANDERS
Meanders
Possible break
through point
Most erosion
on the outside
of the bend .. Fastest flow
Flood plain
Flood plain
© Used with the permission of the Geological Survey of Canada
© Used with the permission of the Geological Survey of Canada
Available at
Available at
http://sts.gsc.nrcan.gc.ca/clf/landscapes.asp
Possible
ox-bow
lake
http://sts.gsc.nrcan.gc.ca/clf/landscapes.asp
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River bend
Fastest current
Formation of an ox-bow lake
slowest current
Bank will
collapse
The Some
river
Eventually
now
follows
during
the
a period
new route
ofMost erosion
bends
get closer
Theheavy
meanders
shapethrough
river change
flow it cuts
and closer
Most deposition
through
time
Small river
(Slip off slope)
cliff is formed
Small
river
cliff
Outer bank
Is undercut
Deepest part
of the river
Slip off slope
( river beach )
Deposition of
Sand and shingle
The bends migrate
At the bends the
Sideways leaving
river flows faster
The
neck
gets
narrower
The
old
meander
deposits on the inside
at
the
outside
The
erosion
the
andasnarrower
Is left
a small lake Of the makes
bend
(OX - BOW lake) Meanders more pronounced
Want to see that again ?
Want to see that again ?
Want to see that again ?
Want to see that again ?
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Want to see that again ?
NARROW MEANDER NECK
FUTURE
OX-BOW LAKE
Gentle valley sides
River is actually flowing above
The floodplain !!
Levees is often
artificially
strengthened
Flat floodplain
Layers of silt
Deposited during floods
Coarse material
Forms natural
levees
Characteristics
Slope
Middle Course
Lower Course
quite steep
gentle
Width
narrow
quite wide
Depth
shallow
quite deep
Straightness winding
Load
little
meandering
Type of load large/small
angular
medium/small
rounded
Main work
Valley width
tributaries
Upper Course
usually steep
some
wide
deep
big meanders
lots
small+
rounded
erosion
Transportation transportation
transportation
deposition
narrow
quite wide
wide
V shaped valley
Steep
Valley
sides
meander
ox-bow
lake
Flood
plain
Reproduced with the permission of the Controller of HMSO
© Crown Copyright NC/02/15232
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