Indiana River Meanders Mapping Exercise
In Indiana, major rivers and their tributaries cross much of the state. These rivers can produce significant hazards related to flooding and erosion, which threaten nearby residents and infrastructure. Rivers are dynamic landforms, and they naturally shift their position on the landscape over time. The path of a river may change rapidly during a flood, or it may slowly evolve over long periods of time.
In this exercise, students use hillshade images derived from airborne lidar (light detection and ranging) from a section of the White River in Indiana to map how the river has changed over the span of five years. Students learn to identify and describe how river meanders and oxbow lakes evolve by comparing the form of the river from 2013 and 2018. Students also use the lidar hillshade to evaluate the longer-term evolution of the river's form and assess how local infrastructure may be impacted. Students are additionally given a plot of river discharge measured from a stream gage station just north of the mapped section of river. They learn how to evaluate changes and trends in river discharge and assess how river discharge can be related to river morphology.
Keywords: river meander, oxbow lake, discharge, geomorphology, lidar
This activity is designed for introductory-level undergraduate college and university students. It is appropriate for introductory-level Earth science, physical geology, or water resources courses. The quantitative rigor of the questions on the lab handout can be enhanced to adapt the exercise for a more advanced geomorphology course.
Skills and concepts that students must have mastered
Students should be introduced to the basic concepts of river morphology and understand how rivers erode and deposit material. It is also helpful if students are introduced to stream gages and are given a brief overview of how river discharge is measured. A PowerPoint presentation is included that provides relevant background information and context.
How the activity is situated in the course
This exercise is a stand-alone activity. It may be introduced during class time lecture and completed as a homework assignment, or it may fit within a relevant laboratory session. It is appropriate at any point in a course when the topic is rivers and/or geomorphology.
Content/concepts goals for this activity
- Identify and map river features on bare-earth lidar hillshade images.
- Analyze changes in river morphology over short and long timescales and relate those changes to the evolution of river meanders.
- Evaluate changes and trends in river discharge by analyzing a graph and interpreting data.
Higher order thinking skills goals for this activity
Students must use critical thinking skills to evaluate the relationship between river/meander morphology and river discharge. They must also be able to interpret features from lidar hillshades.
Other skills goals for this activity
Pre-exercise, students will work in groups to explore Indiana's rivers in Google Earth and discuss what they observe. Working in groups during the exercise may be useful when interpreting data and features. Students will ideally complete the mapping portion and answer quantitative questions individually. However, students will likely benefit from small group discussion to evaluate features in the topographic hillshade image.
Description and Teaching Materials
A PowerPoint presentation is included to accompany this exercise. Instruction should begin with the PowerPoint presentation. Then, students should work in groups and use Google Earth to explore Indiana's rivers. What do they notice? (Are rivers in urban or rural areas? Are the rivers easy to identify? Do the rivers have curvy meanders?) A Google Earth KMZ file of the mapped portion of the White River is included so that students can also be shown the area in Google Earth. Showing the area in Google Earth can be especially helpful to see the difference between aerial satellite imagery and a lidar hillshade image that removes vegetation. The student handout contains all relevant instructions and subsequent questions, including the two lidar hillshade images. A comprehensive answer key and rubric is available for educators. All images in the documents and PowerPoint presentation have alt text descriptions included.
This exercise is also available on OpenTopography: https://opentopography.org/learn/indiana-white-river-meanders-mapping-exercise. OpenTopography facilitates access to high-resolution, Earth science-oriented topography data and related tools and resources.
(1) Student exercise handout (Microsoft Word 2007 (.docx) 7.5MB Jun30 22)
(2) PowerPoint presentation (PowerPoint 2007 (.pptx) 25.4MB Jun30 22)
(3) Google Earth KMZ (KMZ File 28.3MB Jun30 22)
(4) Image files (Zip Archive 45.9MB Jun30 22)
Teaching Notes and Tips
Students should also be provided with digital copies of the lidar hillshade images so that they can view them on the computer at full resolution, as some detail will likely be lost in the printed images. Care should be taken to ensure that students correctly align their map to the images, as misalignments can cause incorrect mapping and misinterpretations of river evolution.
In this exercise, students generate a map with certain areas and features colored and labeled, and they answer 11 questions after completing the mapping. Students should be able to produce a map that reasonably well matches the answer key, highlighting the major changes in the river's form and features related to river meanders. An accompanying rubric is included to grade the map on a scale from 1-12. Questions 1 and 2 also relate to the quality of the map. Qualitative question responses should be well thought out and reasoned and are assigned 3 points (3 pts for thorough effort, 2 pts for reasonable attempt, 1 pt for poor response, 0 pts for no response). Most other questions are assigned 2 points each (2 pts for complete and correct, 1 pt for reasonable attempt, 0 pts for incomplete/incorrect). The exercise has a total of 50 possible points.
References and Resources
- Indiana's Fluvial Erosion Hazard Program: https://feh.iupui.edu/ (The Indiana Silver Jackets supports a program for adopting fluvial erosion hazard (FEH)-avoidance strategies. This website provides additional resources related to FEH and presents real world context for the importance of mitigating FEH)
- USGS Flood Inundation Mapper: https://fim.wim.usgs.gov/fim/ (This interactive map viewer allows you to select certain USGS gage station areas and view how the area would be impacted by floods of a specific magnitude. The Newberry, IN gage station used in this exercise can also be viewed in this mapper)
- OpenTopography's Indiana Topographic Change Map Viewer: https://portal.opentopography.org/indiana (This is an interactive web map showing topographic change in Indiana over a ~5-year span. The differencing results show change from a variety of processes related to the agricultural, forest, river, urban, and coastal environments of Indiana. Students can see that much of the change in the DSM and DTM maps follows where rivers are located.)
- OpenTopography's 'What is Lidar?': https://opentopography.org/lidar_basics (This web page provides additional and more detailed information on lidar and its application in Earth sciences.)