Erosion
Learning Targets
Construct an explanation based on evidence for how geoscience processes (events that shape the Earth’s surface) have changed Earth’s surface at varying times.
Success Criteria
I can:
Define erosion
Identify the causes of erosion
Describe how erosion changes the surface of the Earth
What is Erosion?
Weathering and Erosion go hand-in-hand. Based on what you learned about weathering, what do you think erosion is?
Erosion Mini-labs
In the Erosion Mini-Labs you will learn about the different types of ways that sediments are moved as the result of various weathering forces. You will need a stream table with a pump to continuously move water throughout the system.
Click me for the Labs!
What is a Delta?
A delta is a wetland area that forms as river waters empty into a larger body of water. Often, deltas look triangular in shape and sometimes they're even described as looking like a fan.
Observe the following pictures from Google Earth of several deltas around the world. Can you find any other deltas in other places around the world?
The Nile River Delta
Susquehanna River Delta into Chesapeake Bay
Mississippi River Delta
Use Google earth to find the other deltas on this map.
What is Erosion?
Now that you have complete a few labs about Erosion what do you think would be a good definition for it?
How is Erosion similar to and different from weathering?
What forces cause Erosion?
Erosion Gizmo
Explore how river erosion affects landscapes in the short term and over long periods of time. Describe the features of mountain streams and meandering rivers, and use a floating barrel to estimate current speed. Witness the changes that occur as mountain streams erode downward and meandering rivers erode from side to side.
Click Here for the Assignment
How the Grand Canyon Formed
One of the greatest examples of Erosion in action can be found in the United States! The Grand Canyon in Arizona began to be formed 6 million years ago and is still changing every day!
A Few More Videos
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 3 examples of erosion and take pictures of them. Collect data on when and where you found it. Include what you infer about where it came from and how it was moved.
Log on to Google Classroom and complete the Erosion Walk assignment.
If you were not able to find three example of erosion, do an image search for examples of erosion, choose one and describe it using the criteria on the slideshow (to the best of your ability.)
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.
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.
Further Reading
Erosion on Mars
This article focuses on how the surface of Mars has been shaped by the various forces of Erosion.
Finding Gold After a Storm
This article explains how gold can be found after erosion events such as storms and floods.
What is Erosion?
Read the following article about the various forces that can cause erosion.
