Introduction
Your family just moved into their new home along a river bank. You have been able to fish, hike, and enjoy listening to the water that runs by your house. However, a few severe thunderstorms have resulted in flooding conditions by your home. The water in the river has been flowing at a fast rate. You begin to notice that your backyard is changing due to weathering and erosion. What steps will you take to protect your home and land?
Task
Your next step is to investigate methods that are used to help control erosion along waterways.You have found several ways to solve erosion along a stream bank. Below are some of the ways which might help you solve your problem.
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Cross-Vane Weir Diversion: Large rocks are placed in a V-shaped formation in the center of the stream. This method reduces the stress along the stream bank and channels fast moving water to the center of the stream.
Rip-Rap: Layers of stones are placed in areas to protect against erosion. The stones can be placed in the stream, along a streambank, or areas with poor soil structure. Stones should be large enough to avoid being washed downstream
Tree Revetment: Trees are placed horizontally along the side of the stream bank. The trees greatly slow the current along the eroding bank. The sediment is deposited along the bank between the branches of the tree. This provides a good seed bed to allow vegetation to grow along the bank.
Brush Mattress: A layer of branches is placed along a bank often with rocks at the base. The live branches are cut from trees such as willow. A brush mattress slows the water flowing along the stream bank and collects sediment. This allows the live branches to take root and grow into full size plants.
Process
Plan & Design Models: Based upon the information that you learned about methods to slow erosion, you will design and construct a model of two of the erosion control measures. You will evaluate and test the two erosion control measures to determine if one of the methods works better at controlling erosion.
Evaluation
Conclusion
Student will define a problem or design statement that is realistic and completely matches the intent of the problem and the constraints.
Students will then construct simple, accurate models (e.g. diagrams and/or drawings with labels, etc.) to represent the process to be investigated and explains how the parts of the model represents the “real thing”.