Erosion

MS-ESS2-2. Construct an explanation based on evidence for how geoscience processes have changed Earth's surface at varying time and spatial scales.ESS2.C: The Roles of Water in Earth's Surface Processes

Learning Targets

Students will develop a conceptual model of how the forces of erosion can change the land’s surface features.

Success Criteria

develop a definition of erosion
identify some of the forces of erosion
identify locations where erosion can occur

Roles

Organizer, Time Keeper, Checker, Reader

Questions to Ponder

What is Erosion?
How is erosion different from weathering? How are they similar?
What forces cause erosion?

Erosion Walk

In the Erosion Walk we will travel to various locations around the school and make observations of places where weathered materials have been eroded.
Find 4-6 examples of erosion and record the following:
1. What is the location?
2. Describe the erosion.
3. What caused the erosion?
4. What do you think has happened to the eroded materials?

After the Walk

Compare your observations.
What examples of erosion have you observed where you live?

Back to Teams

Are there any benefits to erosion?
How could you stop erosion?
Create a definition that could apply to all kinds of erosion.

Debate - Beach Renourishment

Beach Renourishment is the process of placing eroded sand back onto beaches.
Beach renourishment can effectively protect a local ecosystem, but it comes at a sometimes steep price. It is up to each local community to determine if they are willing to pay the required price to repair a beach. By weighing all of the pros and cons of this process, the correct decision can be made.

Watch this video about a Beach Renourishment project in Coney Island, NY.

What do you think about Beach Renourishment?

Review the following Pros and Cons so you can decide where you stand.

Pros

Beaches are able to stay intact.

Enough erosion can cause a beach to eventually collapse. This collapse means the local ecosystem collapses with it and create destruction throughout the chain of life. By renourishing the beach, the ecosystem can be saved and therefore preserve the chain of life that exists locally.

It creates a safer beach environment.

Once enough sand erodes from a beach, there can be numerous hazards that could find the feet of visitors or the bellies of sea life. Replacing the sand helps to provide a safer experience for the entire ecosystem.

Beaches are better buffers.

Waves that don’t have a beach to buffer their impact can be a violent force of nature. The waves crash mightily against whatever barrier they do encounter and this added force actually increases the potential for erosion. Beach renourishment helps to keep the gentle buffer in place and provide a better level of protection for nearby properties.

It protects inland properties.

Many beaches have a steep incline that leads up from the water. These inclines are very susceptible to erosion and any moisture may impact them in a negative way. With enough instability present, mudslides and other dangerous situations may occur that could affect lives.

It can secure the environment for future generations.

A properly engineered beach renourishment project can create a permanent beach that will be around for everyone to enjoy for years to come.

Cons

It is a temporary measure to fix a permanent problem.

Ultimately beach renourishment is only a bandage for an ongoing problem. Without a plan to address the erosion issue, eventually beach renourishment will need to occur again and again to preserve the ecosystem.

It alters the natural course of nature.

Natural sand compacts over time as a way to prevent itself from being eroded away. Much of the replacement sand ultimately just floats away with the first waves because it hasn't had time to naturally compact.

It is incredibly expensive.

It is not uncommon for a beach renourishment project to be a $100 million investment. Although some projects have private financing and backing, many of these projects wind up being funded by taxpayers.

The process of renourishment can interrupt natural life cycles.

The process of repairing a beach can be very extensive. Sand is often imported for this process, creating grain variations that can be problematic for local sea life. Even after the repair is completed, the natural life cycle may still be interrupted by changes to wave patterns, the shape of the beach, and other unforeseen factors that occur locally.

It may reduce light availability.

Changes in beach size and shape can affect the way sunlight reaches the shallow tidal zones. In return, plant and sea life can be affected in positive and negative ways. The biggest negative is that lower or higher levels of sunlight can cause species growth to overwhelm the system or species death.