Build a Delta!
This activity has benefited from input from faculty educators beyond the author through a review and suggestion process.
This review took place as a part of a faculty professional development workshop where groups of faculty reviewed each others' activities and offered feedback and ideas for improvements. To learn more about the process On the Cutting Edge uses for activity review, see http://serc.carleton.edu/NAGTWorkshops/review.html.
This page first made public: Jun 6, 2008
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
2. How do bedload and suspended load affect delta formation?
3. How and why does grain size vary within and across a delta? How does river flow-velocity relate to grain size?
4. How to relate conceptual and physical models to a real-world example of a landform.
5. how to relate landform to stratigraphy in a delta specifically, but also in other landforms as well.
Higher order thinking skills goals for this activity
2. how to assess the value (and limits) of physical models, analytic measurements, and field observations.
3. students develop an appreciation for rates of deposition and sediment transport through the use of time-lapse animation of a stream-table delta.
Other skills goals for this activity
2. students create a short report that synthesizes their results from all three labs plus readings from McPhee's "Atchafalaya."
Description of the activity/assignment
Lab 2: In the second lab, we use grain-size analysis of the stream-table delta as a means of testing some of their ideas from lab 1. The students as a class develop a strategy to sample the stream-table delta for grain size, using a laser grain-size analyzer. Each pair of students collect one sample, but are also asked to predict the changes in grain size distribution for samples elsewhere in the delta. The particle size analyzer rapidly provides results to the students near the end of lab.
Lab 3: the final lab is a field trip to a pair of gravel pits that expose the guts of two natural stranded deltas, including topset and foreset beds. The students are asked to assess the landforms on a topo map before arriving, and to describe the deposits at each site we visit. On the final writeup, the students need to synthesize all the elements of the three labs, along with input from our readings in the textbook (Easterbrook) and McPhee's "Control of Nature."
Determining whether students have met the goals
The final writeup is graded using a rubric.
The first midterm includes an essay question about delta formation, relating landform to sedimentology.
Download teaching materials and tips
- Activity Description/Assignment (Microsoft Word 44kB Jun6 08)
- Instructors Notes (Microsoft Word 28kB Jun6 08)
- Lab 2 worksheet (Microsoft Word 68kB Jun6 08)
- Lab 3 worksheet (Microsoft Word 30kB Jun6 08)
- Final report rubric (Microsoft Word 27kB Jul22 08)
- Example of stream-table delta timelapse video (low res) ( 6.6MB Jun6 08)
- Cross section image of stream table delta ( 42kB Jun6 08)