Development of the Controlled Assessment task for 2015

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Transcript Development of the Controlled Assessment task for 2015

Development of the Controlled
Assessment task for 2015
By: Helen Robertson
FSC London
21 October 2013
The Task
What’s different?
Making sense of the task statement
The enquiry process
Possible fieldwork techniques (primary &
secondary data)
• Potential investigations...
Task Information
An investigation into factors that affect
the formation of river landform(s)
• 1.1 What processes are associated with rivers?
• 1.2 What landforms result from these
What’s different?
More traditional than 2014
Not a classic ‘downstream change’ study
Not river management
Focus instead on processes e.g.
– Erosion
– Deposition
– Transportation
• Example
– meanders
Unpacking the title
Must include primary data
collection. A variety of secondary
sources also available .
Processes such as erosion, transportation and
deposition. Distance downstream as a factor
An investigation into factors that affect the
formation of river landform(s)
Making the link between processes and
landforms e.g. How increases in velocity
might influence bedload size on a point
bar or how the width of the channel
may influence meander wavelength etc
Meanders, associated features, channel
and bankfull dimensions, floodplains,
oxbow lakes, V-shaped valleys,
waterfalls & gorges.
The enquiry process
• Involve the candidates in the enquiry process.
– What are they aiming to achieve? – involve
candidates in posing enquiry questions
– What is the wider geographical concept / theory
that is being tested?
– How might candidates take some ownership for
selecting or collecting data? How will they
demonstrate independence?
London’s Lost Rivers
Some suggestions…
• a range of data collection techniques
• opportunities for your students to meet the
criteria in the mark scheme.
Field sketches and photos
• Scope for well annotated
photos & sketches.
• Combined with mapping to
great effect.
• Good opportunity to try less
traditional ideas e.g. ‘a field
sketch from the future or at
bankfull discharge’
• Possible use of mobile
Mapping of River Landforms
• Annotate a base map
• Online mapping software e.g. Google Earth, ArcGIS
online; sketch map; Scribble maps
Mapping of River Landforms
• Hand drawn sketch map
• Choropleth landforms
• Historical Maps /
• Geology Maps
The Hjulstrum curve
• Can processes occurring on
a meander be linked to this
• Straight section vs a
• Pool vs a riffle?
• Two sites with same width
but a different depth?
Bedload Measurements
• Size and angularity
Bedload Measurements
• Measuring any
sorting of bedload
on point bars
• Bedload size across
a cross profile in a
straight and
Bankfull measurements
• width and depth
Valley profiles, sketches and photos
• Link to geology?
• Comparison of sides?
Measurements of the landforms
• Length and
height of river
• Gradients of
slip off slopes
• Both could be
related to
variables like
water speed
or channel
Measurements of the landforms
• Sinuosity = river length/linear distance
Measurements of the landforms
• Meander wavelength and amplitude
• Does CSA of Bankfull C = CSA of Bankfull A +
CSA of Bankfull B
Step pools and comparing gradients
Distance between steps?
Height of steps?
Bedload analysis?
Site important...
Comparison using slope
angle possible…
Channel measurements
• eg velocity, depth,
wetted perimeter,
gradient etc
• Can still be used.. But
not downstream!
– Comparison
– One or two meander
• Compare with past data
Example investigations
• Comparison of a meander and a straight channel –
channel shape, velocity, bedload etc
• In depth study of a meander – dimensions, velocity,
bedload, bankfull and associated features
• The effect of channel characteristics on river cliff/point
bar size and length
• The effect of slope angle on step-pool or pool-riffle
• Channel characteristics & their influence on meander
• Channel A + Channel B = Channel C
Investigation questions
• How and why does the shape of the river channel affect the process
of deposition?
• How and why does the shape of the river channel affect the process
of erosion?
• How do meanders influence erosion?
• How do meanders influence deposition?
• The wavelength of a meander is greater where the river channel is
• How do meanders influence bedload size and/or shape?
• Channel sinuosity increases with increased channel
• Length/height of river cliff increases with increased
velocity/discharge. Stream gradient influences ‘step-pool’
• Contact:
– Helen Robertson
– FSC London
– [email protected]