grs03/03/16
Rivers, physical.
Aims:
 To identify the main features of the drainage basin.
 To understand how the storm hydrograph operates and identify the human impact on the hydrograph.
 To identify how the geomorphological features change within the drainage basin.

Rivers, floods and management
The drainage basin hydrological cycle: the water balance.
Factors affecting river discharge: the storm hydrograph.
The long profile – changing processes: types of erosion, transportation and deposition, types of load; the Hjulstrom curve.
Valley profiles – long profile and changing cross profile downstream, graded profile, potential and kinetic energy.
Changing channel characteristics – cross profile, wetted perimeter, hydraulic radius, roughness, efficiency, and links to
velocity and discharge.
Landforms of fluvial erosion and deposition –potholes, rapids, waterfalls, gorges, meanders, braiding, levees, flood plains
and deltas.
Process and impact of rejuvenation – knick points, waterfalls, river terraces and incised meanders.
Magnitude-frequency analysis of flood risk.
Physical and human causes of flooding – two case studies of recent flooding events should be undertaken from contrasting
areas of the world.
Impact of flooding – two case studies of recent flooding events should be undertaken from contrasting areas of the world.
Flood management strategies – to include hard engineering – dams, straightening, building up of levees, diversion spillways,
and soft engineering –
forecasts and warnings, land use management on floodplain, wetland and river bank conservation and river restoration.
River DVD
grs03/03/16
Key Questions
Suggested Pupil activities/methods
What is meant by
the drainage
basin? How can
it be represented
by a system
approach?
Draw basin run off system and def terms.
interception, stemflow, dripflow, overland,
through, infiltration, percolation, groundwater.
Draw the flow diagram for the drainage basin
What is the
significance of
the hydrograph?
How is discharge
measured?
What are the
controlling
factors that affect
the hydrograph?
Water budget, ex on website
Ex on P 11
PPT, as a summary Hydrological flows
Draw the flood hydrograph.
PPT to explain how
Ex to draw hydro
Discuss ‘shape’ of hydrograph as storm
progresses
Examples of calculation
Go through examples from Wye or other data
Discuss the factors that control the shape of the
hydrograph including effect of man.
Resources
Text
8
DVD
12
11
14
6
Misc
Red 2,3,4
Nagle 58 ++
GIAA P50 Knapp Ex1
Bishop Ex 18,19
GeoR 7,3,
Ross 224
Landmark 14
Red 4
Landmark 25
Waugh 53
Red 5-7
Ex of figs for discharge
Figs for storm hydro
Carter 1
GeoFact 83
Geofile 87
GeoFile 16,316, Catchment area
(Drainage basin) studies
Geofile 25, 542 Hyrographs and
physical/human impacts
GeoR 4,5
Bishop, Water CH 3
Ex of figs
GIAA P55
GeoR 3,2
Ross 229
Waugh 53
Hordern 5
Landmark 14
Geo Fact 189
Red 4
Landmark 25
Sugg and skills
Comparing
graphs
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What are the
main methods of
erosion?
What are the
main methods of
transportation?
What are the
main
measurements of
a channel?
How do all these
relate to field
work?
Discuss hydraulic action, abrasion, solution and 19
attrition.
Also consider vertical, lateral and headwater
erosion.
Define suspension, solution, saltation and
19
traction. How is velocity linked to
transportation? (Hjulstrom). Discuss
competence and capacity.
Discuss wp, HR, w/d ratio and their influence
on efficiency. Intro. Mannings(?)
Roughness and link to velocity and discharge
Use diagram Ross 241
Bradshaw
Cross section ex
Ppt of HR
HR exercise
Eg data for HR
Case study R Derwent
Also
9
Red 7
Red 9
Ross 240
Waugh 65
Horndern 27
Nagle 95
Red 17
Waugh 63
Ross 242
Nagle 81
Clowes 102
Horndern 22
Ross 243
Nagle 103
Data from sheets
Triangle graph
of bedload size
Dispersion and
scatter graph
Spearman’s
Mean median
and mode
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How does the
long profile of a
river change?
What are the
landforms
associated with
fluvial erosion?
What are the
landforms
associated with
deposition?
What are the
physical causes
of floods?
Draw a simple long profile and then using an
OS map draw an actual one; try one on Arran
2003(?)
Discuss effect of rejuvenation and mark knick
points on profile, note landforms e.g.
waterfalls, rapids and incised meanders,
terraces. Also impact of humans e.g. dams
Note impact of climate change on this
Consider how the valley cross profile changes
downstream
The importance of potential and kinetic energy
Rejuvenation
16
Discuss formation of:
V shaped valleys,
potholes
Rapids,
Waterfalls e.g. High Force
Gorges
Emphasize processes here
Consider:
braiding
Meanders, and ox bows
Flood plains and levees, link above with
sediment deposition across valley floor.
deltas
17
Go through the physical causes of floods
Go through recurrence intervals, frequency
24
Red 13, 23
Data in Clowes P 133
Waugh 69, 74
Horndern 13 19
Nagle 101
Memory map to
show section(?)
Red 14
Red 16
GeoFile 621
19
12
34
Red 18
Waugh 69
Ross 245
Nagle 87
Ross 246
Landmark 15, 16
GeoAct 330
Red 19
Ross 248
Waugh 71
Nagle 93, 96
Carter 3
Geofile 26 563
Landmark 23
Red 26
Carter 2
Red 27
WW 14,1,1
Annotated
sketches
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What are the
human causes of
floods?
Discuss what have humans done to increase the
likelihood of a flood event, link to flood
hydrograph
Compare LEDC and MEDC either
Boscastle, Carlisle and Bangladesh 2004
Just causes here and impact
How can the
flood hazard be
managed?
Go through hard and soft strategies
Hard: dams, straightening, levees, diversion
spillways,
Soft: channelization and naturalisation
Case study of Windsor flood relief channel
Conway valley flood 2004
Hi tech 21st century flood warnings
Case study Carlisle and Bangladesh for cost
benefit
Revision
http://www.geographypods.com/2-drainagebasins-and-flooding.html
A range of physical taboo words for the Rivers and
Coasts topics. Taboo is played in teams each player has 1
minute to describe as many bold words as possible
without
26
28, 41
30
36
Red 27
11
48
63
Red 26,31
Geoactive 17341 19394
WW 16,3,8
GeoFact 45, 189, 233
Red 33
Ross 254, 259
Horndern 46
Geofile 14 268 16, 330
19 399,
WW 9.3,4
GeoFact G206
Landmark 20
38, 41
Geog R 19,1,30, Flood hazard in
the Conwy Valley
Geog R 20,1,24 Hi Tech flood
warnings
GeoFact 45
grs03/03/16
Rivers: flooding and flood management
Key Questions
What are the
physical causes
of floods?
Suggested Pupil activities/methods
Go through the physical causes of floods
Go through recurrence intervals, frequency
Resources
Text
24
DVD
12
34
Misc
Red 26
Carter 2
Red 27
WW 14,1,1
Sugg
grs03/03/16
What are the
human causes of
floods?
Discuss what have humans done to increase the
likelihood of a flood event, link to flood
hydrograph
26
Compare LEDC and MEDC either Boscastle
and Bangladesh 2004
Just causes here and impact
28, 41
Red 27
11
48
63
Red 26,31
Geoactive 17341 19394
WW 16,3,8
GeoFact 45, 189, 233
Case study of
Cockermouth
flood Nov 2009
North Pakistan
July 2010
Cockermouth resource
Powerpoint of flood
Briefing note on cause of flood
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How can the
flood hazard be
managed?
Go through hard and soft strategies
Hard: dams, straightening, levees, diversion
spillways,
Soft: channelization and naturalisation
Case study of Windsor flood relief channel
Conway valley flood 2004
Hi tech 21st century flood warnings
Case study Carlisle and Bangladesh for cost
benefit
30
36
Red 33
Ross 254, 259
Horndern 46
Geofile 14 268 16, 330
19 399,
WW 9.3,4
GeoFact G206
Landmark 20
38, 41
Geog R 19,1,30
20,1,24
GeoFact 45