Unit 4: Transition from Glacier Margin to Land

Alia Khan (Western Washington University)
Twila Moon (University of Colorado, Boulder)
Spruce Schoenemann (University of Montana Western)

Initial Publication Date: October 11, 2023

Summary

Transition from Glacier Margin to Land

Students dive further into the seasonal pattern of glacier meltwater production. By comparing river basin discharge data from basins with more or less current glaciation, students uncover the influences of glaciers on the terrestrial hydrology of a region.

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Learning Goals

Driving Question: What are the temporal changes and physical properties of glacial meltwater for pro-glacial regions of a glacier basin system?

Learning Goals: Evaluate how seasonal changes in temperature influence the overall hydrology of a glacier basin system

Context for Use

The content in Unit 4 is appropriate for upper-division geology, environmental sciences, meteorology, and other geoscience courses; junior/senior-level courses in which geomorphology, climatology, or glacial geology studies are building on prior introductory material. Unit 4 activities can easily be adapted to serve small- or large-enrollment classes and can be executed in lecture and lab settings as an interactive lecture activity, an in-class activity in which students work in small groups, a short lab exercise, or as part of a ~three-week investigation incorporating GIS and Interactive Environments to understand a glacier basin system and cryosphere using the entire Exploring the Glacier Basin System module. This is the fourth unit in the Exploring the Glacier Basin System module and explores glacial runoff and river discharge differences between basins with different amounts of glacier melt input.

Description and Teaching Materials

Part 1:

Students begin by exploring the 360IE to get a sense of the seasonal changes in river discharge from a glaciated basin, in this case the Watson River in the Kangerlussuaq Glacier Basin System.

360 Interactive Environments

Students first draw what they predict as the hydrograph for a glaciated and in the middle of the watershed of a much less glaciated basin. Students can also be asked to draw the hydrograph in three sections: 1) headwaters, 2) mid-section, 3) mouth of river.  Then students can be asked if they expect more variability in the hydrograph along the length of the watershed in Greenland or WA state.

Students then plot (via Excel) stream discharge from the Watson River stream gauge throughout the seasons and match them with photos of high and low flows (Image Slidedeck below). Then students plot and compare it to a basin from the Nooksack River in Washington State with very little glaciation (referred to in the unit as unglaciated).  While the Nooksack River watershed does have inputs from snow and ice melt, the predominant source of water is rain, especially at lower elevation in the basin.  Spring sees a snowmelt pulse higher in the watershed, and glacier melt provides coldwater fluxes during the summer dry season. Help students explore how and why the shapes of hydrographs are very different between the Watson River in Greenland and Nooksack River in WA state.

Extra Resources: 360 Equivalent Images

What we learned:

  • Seasonal variability in stream discharge in a glaciated basin.
  • Seasonal variability in stream discharge in a less-glaciated basin.
  • Differences in hydrology across glaciated and less glaciated basins.

Teaching Notes and Tips

Teaching with 360-degree Interactive Environments

For those teaching with IEs within the modules, please follow the generalized instructional workflow and provide students with the accompanying worksheet available here: PolarPASS Instructor Guide and Student Worksheet 360IE.pdf (Acrobat (PDF) 216kB Jan5 23). The workflow file also contains additional instructor resource slides that detail the various features within each scene of the IEs intended to assist instructors in creating a scavenger-hunt style activity for students (described in the workflow).

Tips from Other Instructors

  • Introduce a number of thought experiments as students work through this Unit. For example, think about a spectrum of hydrologic basins and speculate about how they vary; the basins covered in this Unit are geographically far - would you expect something different from close-by basins with different amounts of glaciation; how might terrestrial runoff compare with runoff come more directly from glacier melt.

Assessment

Assessment: Mod 1 Unit 4 Assessment.docx (Microsoft Word 2007 (.docx) 699kB Aug18 22);

Graph Reading and Interpretation Assessment: Students interpret hydrographs from different geographic settings (glaciated vs. mostly unglaciated) and describe what factors influence the pattern of annual discharge for the different data sets.

References and Resources

Hydrology data: Watson River discharge for Part 1: Watson River Monitoring and Annual Discharge: https://promice.org/WatsonRiver.html

Meltwater discharge: van As, D. et al. Reconstructing Greenland Ice Sheet meltwater discharge through the Watson River (1949–2017). Arctic, Antarctic, and Alpine Research 50, 1–11 (2018). https://doi.org/10.1080/15230430.2018.1433799

Hydrology data source for unglaciated basin discharge for Part 1:USGS data from multiple rivers in WA state: https://pubs.usgs.gov/wri/wri024190/pdf/wri024190.pdf.