Deltas and coastal sediment transport
Summary
Coastal deltas form at the mouths of big rivers with constant high fluvial discharge and sediment supply. They prograde (i.e. build out) into ocean basins. Deltas respond to changes in sea level, fluvial flow, and sediment supply. These changes can occur naturally or be brought on by human activity (e.g. dam building can hold back water and sediment like we talked about in class for the Nile Delta). Understanding how deltas have responded to changing boundary conditions in the past is useful to predict how they will evolve in the future.
This activity is a lab designed for second or third year geomorphology or physical geography students. The lab involves three activities. First, students we will hypothesise and then recreate how changes in sediment supply, river flow, and sea level impact on sediment transport in deltas using an EMRiver stream table. Second, a series of videos from University of Nevada Las Vegas (2011) will be used to view sediment transport in cross section and observe and describe changes in response to changing sea level and other boundary conditions. Lastly, students will use A3 satellite imagery (from NASA) to assess the drivers of modern change in the Yellow River Delta.
The overall lab exercise is framed around changes in environmental conditions that would have occurred during the Holocene, including modern change largely driven by anthropogenic activity and sea level rise.
Learning Goals
Content/Concept Goals:
- To understand how changes in boundary conditions impact on sediment transport in deltas.
- To become familiar with sediment transport processes (e.g. progradation) in coastal river deltas.
- To understand how people can modify the natural processes of delta evolution.
Higher order thinking skills goals:
Formulation of hypotheses about how coastal river deltas respond to:
- Changing sea level, river flow, and sediment supply as boundary conditions;
- Human impacts.
Other skills goals:
Creating a conceptual diagram.
Context for Use
Type and level of course:
This activity is a lab designed for second or third year geomorphology or physical geography students.
Students must have mastered before beginning:
- Delta formation and sediment transport processes
- Boundary conditions needed for deltas to form
- Human impacts on deltas
- Impacts of changing relative sea level
- Fluvial sediment transport
- Wave vs tide coasts.
How situated in a course:
A standalone lab (2 hours) following a lecture block on deltas (2-3x 1-hour lectures)
Description and Teaching Materials
Lab activity is described in the attached file below. Credit is given for any urls and image sources in the final reference list on the document.
Coastal deltas form at the mouths of big rivers with constant high fluvial discharge and sediment supply. They prograde (i.e. build out) into ocean basins. Deltas respond to changes in sea level, fluvial flow, and sediment supply. These changes can occur naturally or be brought on by human activity (e.g. dam building can hold back water and sediment like we talked about in class for the Nile Delta). Understanding how deltas have responded to changing boundary conditions in the past is useful to predict how they will evolve in the future.
The lab involves three activities. First, students will hypothesize and then recreate how changes in sediment supply, river flow, and sea level impact on sediment transport in deltas using an Emriver stream table. Second, a series of videos from University of Nevada Las Vegas (2011) will be used to view sediment transport in cross section and observe and describe changes in response to changing sea level and other boundary conditions. Lastly, students will use A3 satellite imagery (from NASA) to assess the drivers of modern change in the Yellow River Delta.
The overall lab exercise is framed around changes in environmental conditions that would have occurred during the Holocene, including modern change largely driven by anthropogenic activity and sea level rise.
Lab activity handout (Microsoft Word 2007 (.docx) 1.4MB Aug28 26)
Teaching Notes and Tips
EM2 stream table is used. I do a run through with students first to show them how it works and discuss how to be safe around it.
Assessment
Labs are marked with a rubric/model answers. Final % score is converted to a letter grade.
References and Resources
All references are cited on the lab handout in a final reference list.