Oklahoma Water Resources Center

OSU Stream Trailers Teach Vital Lessons about Streams and Rivers


by Jonathan Anthony, OWRC staff writer

How do rivers and streams behave over a stretch of time? What is the point of vegetation on the banks? How do activities upstream or downstream of my property affect the stream running through my land?

What if there was a reliable way to show the answers to these questions and more?

Marley Beem, pond extension specialist at Oklahoma State University (OSU), and Garey Fox, interim director of the Oklahoma Water Resources Center, recommend the OSU stream trailers. Stream trailers demonstrate the features and processes found in rivers and streams, including channeling and stream bank sloughing by using a recirculating water flow system and light-weight plastic grit (in place of soil).

As overseer of the stream trailer program, Beem has developed five major lessons that educators can teach with this simple tool.

1. Why do streams curve and wind?
The educator begins the demonstration by pumping water onto the bed and channels begin forming in the plastic grit. Water takes the path of least resistance, winding around obstacles in a phenomenon known as meandering. Even with a straight channel for the water to flow down, the trailer is effective in showing how creative water is at finding new pathways. This shows the viewers it is impossible to prevent a stream from naturally changing pathways over time.

2. Why does flooding happen and is it natural?
By simulating a large rainfall event, stream trailers can replicate the flooding that results. Dr. Garey Fox explained, “the trailers are great at showing how flooding and erosion are natural. Streams are like living organisms and can’t be held in place.” Educators can also use this opportunity to show how urban development can increase stormwater runoff and flooding. With small houses set up in the stream trailer’s floodplain, the viewer can see increased runoff impacting both the simulated stream and the downstream residences.

3. Is streambank vegetation valuable?
Small tree figurines and mesh fabric are used to show the viewers how plant life next to the stream can reduce streambank erosion. As water flows through the stream channel, this root network reinforces the bank like rebar in concrete. Marley Beem highlighted this as his favorite feature and uses it to demonstrate the value of streambank vegetation to landowners. “The erosion process is so gradual in the natural setting,” Beem said, “that we otherwise have a hard time seeing the vegetation is doing a job for us and often what we see as normal is not desirable.”

4. What happens when streambank soil is eroded?
Despite the help from streambank vegetation, portions of streambanks erode and fall into the river constantly.  This mixture of soil and rock polluting the water is called sediment, which can be harmful to water quality by reducing the available sunlight and oxygen. At the end of the demonstration, the educator removes the reservoir at the bottom of the trailer and shows it to the viewers. The tray becomes filled with sediment throughout the lesson, and is an effective tool to show how much slips by unnoticed. Dr. Fox notes in his presentations, “this sediment is the biggest expense in water treatment. All of it has to be filtered out before the water is potable.”

5. Can I play with the stream trailer to see what will happen if …?
Yes! Viewers are encouraged to manipulate the stream trailer features in creative ways. For example, Dr. Fox challenges his engineering students to try new experiments and install structures. When students build a bridge pier or abutment, the stream trailer is realistic enough to mirror the different holes formed when water flows around these structures. Even stream channels can be altered if students build structures to divert flow away from eroding banks and around a landowner’s property.

Outside the classroom, stream trailers are also effective for teaching the public through experimenting with its features. The American Society of Agricultural and Biological Engineers  invites OSU to bring a trailer to the annual FFA Convention to help recruit students into science, technology, engineering, and mathematics, where approximately 2500 students, parents, and teachers see it annually. Dr. Fox is also invited to take a stream trailer to a local elementary school’s outdoor day to “inspire budding scientists and engineers by helping the 4th and 5th graders understand terms they learned in class, such as floodplains, deltas, erosion, or the mouth of the river.”

If you are interested in using a stream trailer to learn or teach, you can learn more at http://water.okstate.edu/programs/extension/demonstrations-services or find your nearest source at http://streamtrailer.okstate.edu. If interested in having one constructed for yourself, contact Marley Beem at marley.beem@okstate.edu.

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