Initial Publication Date: July 27, 2010 | Reviewed: November 3, 2013

Using a GIS to Assess Stream-Channel Migration

Douglas Clark, Geology Dept., Western Washington University


This lab uses a guided GIS worksheet to help new Geomorph students to investigate a basic problem about rivers: how do channels migrate.


Type and level of course
Geology 310 is in our BS core, and is usually the second or third class our majors take. However, it also fulfills several general education requirements for other majors, so we have significant non-geology majors in it too.

Geoscience background assumed in this assignment
the only requirement for the class until this year was Physical Geology. Next year we will require Geology 213, intro to GIS, so the exposure to GIS should be significantly improved.

GIS/remote sensing skills/background assumed in this assignment
Very little so far, but at least beginning experience starting next year.

Software required for this assignment/activity:
ArcMAP v. 9.2

Time required for students to complete the assignment:
~3 hours


GIS/remote sensing techniques students learn in this assignment

  1. how to navigate to and import data files
  2. how to move data and metadata files
  3. how to create polygons and polylines
  4. how to create different layers on a GIS project
  5. how to measure area and distances

Other content/concepts goals for this activity
to gain a sense of the magnitude and rates of channel migration for rivers, particularly braided vs. meandering channels.

Higher order thinking skills goals for this activity
very little of this in this stage of the lab. the main goal has been to get the students familiar with GIS so that they can potentially use it for future research projects in the class.

Description of the activity/assignment

This lab is part of a larger study in which the students read some literature on river channel forms, have a lecture on it, and also follow it with a field trip to the sites they study on the GIS. In the lab, the students create a GIS and import several sets of historic digital ortho photos for two different sites on the Nooksack River, one with a braided character, and one with a meandering channel. Then they use the polyline function to map out channel margins in each set of photos, and end by comparing the different channel margins through time, measuring the changes in distance and (optionally) in area. The lab mainly gives them exposure to working with a GIS on a Geomorphic problem, and some sense of the potential value of the tool.

Determining whether students have met the goals

We evaluate the channel-margin maps they make for accuracy (compared to a master version) and also their measurements. We also have an inclass discussion of the problems they encountered and the benefits they found.
More information about assessment tools and techniques.

URLs and References
Many of the digital orthophotos for this lab are available at this site.

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