Development of the Controlled Assessment task for 2015

1. Development of the Controlled Assessment task for 2015 By: Helen Robertson FSC London 21 October 2013

2. The Task • What’s different? • Making sense of the task statement • The enquiry process • Possible fieldwork techniques (primary & secondary data) • Potential investigations...

3. 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 processes?

4. 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

5. Unpacking the title An investigation into factors that affect the formation of river landform(s) Must include primary data collection. A variety of secondary sources also available . Processes such as erosion, transportation and deposition. Distance downstream as a factor discouraged. 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.

6. 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?

7. Location?

8. London’s Lost Rivers http://strangemaps.wordpress.com/2008/06/05/284-londons-lost-rivers/

9. Location?

10. Some suggestions… • a range of data collection techniques • opportunities for your students to meet the criteria in the mark scheme.

11. 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 technology

12. Mapping of River Landforms • Annotate a base map • Online mapping software e.g. Google Earth, ArcGIS online; sketch map; Scribble maps

13. Mapping of River Landforms • Hand drawn sketch map • Choropleth landforms • Historical Maps / Images • Geology Maps

14. The Hjulstrum curve Can processes occurring on a meander be linked to this theory? Straight section vsa meander? Pool vs a riffle? Two sites with same width but a different depth?

15. Bedload Measurements • Size and angularity assessments

16. Bedload Measurements • Measuring any sorting of bedload on point bars possible. • Bedloadsize across a cross profile in a straight and meandering channel?

17. Bankfull measurements • width and depth

18. Valley profiles, sketches and photos • Link to geology? • Comparison of sides?

19. Measurements of the landforms • Length and height of river cliffs • Gradients of slip off slopes • Both could be related to variables like water speed or channel width/depth

20. Measurements of the landforms • Sinuosity = river length/linear distance

21. Measurements of the landforms • Meander wavelength and amplitude

22. Does CSA of Bankfull C = CSA of Bankfull A + CSA of Bankfull B C A B

23. Step pools and comparing gradients • Distance between steps? • Height of steps? • Bedload analysis? • Site important... • Comparison using slope angle possible…

24. Channel measurements • eg velocity, depth, wetted perimeter, gradient etc • Can still be used.. But not downstream! • Comparison • One or two meander sites? • Compare with past data

25. Example investigations • Comparison of a meander and a straight channel – channel shape, velocity, bedloadetc • 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 characteristics • Channel characteristics & their influence on meander wavelength/sinuosity • Channel A + Channel B = Channel C

26. 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 wider. • How do meanders influence bedload size and/or shape? • Channel sinuosity increases with increased channel width/discharge. • Length/height of river cliff increases with increased velocity/discharge. Stream gradient influences ‘step-pool’ characteristics.

27. Questions? • Contact: • Helen Robertson • FSC London • enquiries.ldn@field-studies-council.org • www.field-studies-council.org/london