Activity 5: Waves and Erosion
- Understand erosion, why preventing erosion is desirable, and how aquaculture operations can be used to prevent erosion.
- Learn about the engineering design process.
- Use resources and collaboration to solve a problem.
Time to complete activity: 60 minutes
Background for facilitator
Note: All links are provided purely for educational purposes. No responsibility is assumed for any content on the linked site(s).
Beaches are an important natural resource, but beaches are losing more and more sand each year, as a result of inlets and jetties, erosion, and rising sea levels. The maintenance of beach nourishment (filling sand where it has been eroded) is very expensive and could be potentially dangerous, and is a temporary solution. In this activity, youth will develop a cost-effective and environmentally healthy engineering solution to show how aquaculture operations can be strategically developed and sited to reduce shoreline damage.
Coastal erosion is the process by which wave action wears away beaches and shorelines. Climate change predictions include both larger storms, which will increase wave action, and sea-level rise. These changes will lead to an increase in coastal erosion, which will result in loss of property for landowners, and potentially cause millions of dollars worth of damage each year.
The placement and structural type of aquaculture operations can influence how waves travel to and interact with the shoreline. This can either make shoreline erosion worse or provide protection to the shore.
You may wish to revisit this video: What Is Aquaculture? (YouTube).
Note: At this time, sea vegetable/kelp farming is being researched as a shoreline erosion control measure. However, we would like youth to fully explore the design process, so please do not share this information with youth until after the activity!
Key concepts to address throughout this activity
- Youth will design a process to slow down coastal erosion of beaches using the engineering design process.
- This structure will also be an aquaculture operation – either farming of sea vegetables or animals. This can include pens for fish or lines for sea vegetables (seaweeds) or species like oysters or mussels.
- Erosion: the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth’s crust, and then transports it to another location
- Weathering: the breakdown of rocks at the Earth’s surface, by the action of rainwater, extremes of temperature, and biological activity. It does not involve the removal of rock material.
- Deposition: the laying down of sediment carried by wind, water, or ice. Sediment can be transported as pebbles, sand & mud, or as salts dissolved in water. Salts may later be deposited by organic activity (e.g. as sea-shells) or by evaporation.
- Wave: a disturbance on the surface of a liquid body, as the sea or a lake, in the form of a movingridge or swell.
- Jetty: a structure extended into a sea, lake, or river to influence the current or tide or to protect a harbor.
- Levee: an embankment built to prevent the overflow of a river.
- Large aluminum pans/trays
- Sand (12 plastic bags)
- Toy houses
- Scissors (6)
- Goggles (25)
- Rulers (6)
- For construction:
- Fabric strips (8” x 1” strips)
- Wire mesh strips (8” x 1” strips)
- Clay – one block per group
- Chenille stems
- Sheer tights (8” x 1” strips)
- Paint mixing sticks (10) – one per group
- Newspaper (~30 pages)
- Poster showing all the options for construction materials
- Ask youth what they know about erosion. Discuss why it is important, and make sure that connections to aquaculture are mentioned in the discussion.
- Explain to youth that they will be designing an environmentally friendly aquaculture operation which also will protect beaches from erosion through engineering.
- Discuss the following questions:
- Who are our clients?
- What do we need to create
- What do you think other people have done to solve a problem like this?
- What are our limitations and constraints?”
- Individuals in what type of careers would work to solve a problem like this?
- Would they work alone, or together?
- Divide youth into teams of four.
- Explain to youth that their group will be designing and constructing an aquaculture operation with a secondary goal of erosion reduction.
- The design has several constraints:
- Everyone must have three inches of “beach” (sand) out of the water and no more to start.
- The ocean will consist of a depth of 1.5 inches of water.
- All waves will be created by a facilitator or instructor lifting the pan opposite the beach, one inch off the table, and putting it back down twenty times.
- Introduce the materials to the youth. Identify and name all of the materials. Youth will only be allowed to use the materials provided. They may not use any additional materials.
- Inform youth that you will be acting as the project manager for their engineering firm. As project manager, you require that each group submit their blueprint design before requesting materials. Groups must get your signature on their blueprint before they are able to collect materials and create their initial product.
- Give the groups about 10 minutes to create a drawing of their proposed product. The groups should estimate how much of each material they will need when creating their product, so that we can cut down on our waste. Each group will only be able to collect materials once during their initial design and then once during their redesign.
- Have one member of each group collect materials. Remind them that they can only collect once during this initial design.
- Give groups 20 minutes to create their prototype.
- After creating their prototype, groups should create a name for their product.
- Students will now conduct a guided inquiry as a group to test the effectiveness of their product.
- Encourage students to use the scientific process.
- Ask students to formulate a hypothesis. As a whole group, work together to choose which group’s product will perform the best, when compared to the other products in the class.
- If we choose the product “___________” to reduce coastal erosion, then it will be the most effective because ______________________________________.
- Identify all of the variables: What are we measuring? What is changing? What remains constant?
- Now it is time to test the products. As a group decide how you will measure success.
- Groups will test their products one at a time.
- As the facilitator, you will lift the pan opposite the beach 1 inch off of the table and then put it back down 20 times. Make sure that everyone can see it!
- Have the youth write down observations and analyze the process. How effective is each design in preventing erosion?
- After each group’s design has been tested, the groups will now have the opportunity to redesign their product to make it better. A first trial in engineering is like a first draft in writing.
- Ask the students to talk in their groups about how they can improve their design. They should not completely restart, but instead adapt their current design. Give the groups around 10 minutes to improve their blueprint.
- From there, groups can request additional materials and spend 15 minutes adapting and building their final products.
- Re-conduct the test as a whole group and discuss observations.
- Ask: “Why are some designs more successful than others?”
- Decide which design was ultimately the most effective and why.
- Ask youth to brainstorm how severe weather affects coastal erosion. How might physical location related to coastal erosion?
- The steps of the engineering design process are as follows:
Discuss how youth used the engineering design process to solve this problem. Go through the steps of the engineering design process and ask youth to reflect on what they did today that reflects each step in the engineering design process.
- Ask youth why the engineering design process is a cycle.
- Compare and contrast the engineering design process with the scientific method.
Have youth explore current models being utilized in local areas to address coastal erosion. Are any of them utilizing aquaculture? If not, how might that benefit the area?
- More on coastal erosion can be found in the U.S. Climate Resilience Toolkit.
- Images of severe coastal erosion, such as that caused by hurricanes, can be found at the NOAA Photo Library.