Stream Morphometry, Stream Flow, Stream Competence

Alec Aitken, University of Saskatchewan
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This exercise combines field activities (i.e., topographic survey of a point bar; sediment sampling with a soil auger), laboratory analysis (i.e., particle size analysis of fluvial sediments), topographic map interpretation, and problem solving exercises.

Key words: point bar, fluvial sediments, topographic surveying, particle size analysis, stream morphometry, stream discharge, stream flow competence

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A second year undergraduate course focused on the physical processes of weathering, erosion, transport and deposition of clastic sediments. A required geosciences course for BSc majors in Environmental Earth Sciences and a senior geosciences elective for BSc majors in Archaeology and Geology.

Skills and concepts that students must have mastered

  • Recording field observations on data sheets.
  • Acquiring information from topographic maps, e.g., converting distancesmeasured on a map to distances on the ground.
  • Solving simple algebraic equations for unknown variables.
  • Familiarity with the Wentworth scale for classifying the particle size of clastic sediments.
  • Familiarity with the following concepts: Manning's and Chezy equations to estimate stream flow velocity; Shield's parameter and fluid shear stress in open channel flow; Froude Number; Hjulstrom diagram
  • Familiarity with MS EXCEL worksheets is an asset

How the activity is situated in the course

Part of a sequence of exercises.


Content/concepts goals for this activity

Explore the relationships between stream morphometry, stream discharge and stream flow competence.

Higher order thinking skills goals for this activity

Data analysis and interpretation.
Problem solving.

Other skills goals for this activity

Working in groups to acquire topographic survey data and sediment samples.
Dry sieving sediments for particle size analysis.
Data visualization (i.e., construct histograms).
Provide succinct written responses, i.e., data interpretation.

Description and Teaching Materials

The exercise is the last of a sequence of 3 exercises. The first exercise (not included) involves the collection of topographic survey data and sediment samples using a soil auger from a local point bar. Students are organized in groups of 5 to perform these tasks. The second exercise (not included) involves pairs of students performing dry sieving of the field samples to determine the particle size distribution of the sediments. This exercise uses the topographic survey data and particle size analysis data to support a variety of problem solving exercises.
Steam Flow and Competence (Microsoft Word 61kB Jun3 14)
Sutherland Beach Topographic Survey (Excel 32kB Jun3 14)
Fluvial grain size data (Excel 38kB Jun3 14)

Teaching Notes and Tips

For the field portion of this sequence of exercises course instructors should be familiar with the use of an Abney clinometer as topographic surveying device and the proper recording of survey data on data sheets.
Make sure to incorporate sufficient time to demonstrate the proper use of the Abney clinometer and the soil auger, and to review the data recording protocol. My experience suggests that students require ~ 1.5 hours to complete the surveying and soil sampling in the field.

Field safety is of utmost concern. Please inform yourself of institutional policies related to out of classroom activities. Basic first aid training is an asset; course instructors should carry a basic first aid kit at all times. Work out an emergency plan in case someone must be evacuated immediately from the field.

For the practical laboratory portion of this sequence of exercises course instructors should incorporate time to demonstrate the proper and safe use of the sieves and the analytical balances employed to determine the mass of the various sediment fractions.

For this exercise, a 2 hour tutorial lead by the teaching assistant or course instructor is appropriate for assisting students with the problem solving exercises.


Data visualization: marks are awarded for each element of the histogram; properly labelled axes, bar heights correctly displayed, provision of an informative title.

Students are required to provide fully worked solutions for all of the problem solving exercises.

A grading rubric is established for the assessment of the written responses.

References and Resources

I refer students to the course lecture notes (posted on Blackboard) and the assigned reading from the required course textbook.

Alan S. Trenhaile, 2013. Geomorphology: A Canadian Perspective. 5th Edition. Oxford University Press, Don Mills, Ontario. 575 pages.