Erosion simply means to wear away or cause to diminish. Erosion is the process that occurs when a surface or substance wears away slowly. It is often the result of corrosion, or of one substance eating into another. There are many types of erosion. Develop a deeper understanding of this scientific concept by reviewing several examples of erosion.
Water Erosion From Rainfall or Melting Snow
Water erosion occurs when soil ends up being detached, removed, or washed away by water. It can be related to rainfall or running water, such as the movement of a significant quantity of melting snow. There are several examples of this type of erosion.
This type of erosion is caused by rainfall. It is the first stage in the process of water erosion. When raindrops hit the soil, they cause individual soil particles on the ground to disperse and splash back down. This makes it difficult for rain to permeate the ground, so the water builds up on the surface and leads to the formation of moving water, in the form of runoff.
- a small crater forms in bare soil as a result of pouring rain
- particles of soil piled up so to form puddles of rainwater
Also caused by rainfall, sheet erosion is a more severe form of erosion than splash erosion. It is the sheet-like washing away of loosened particles of soil. It is caused by runoff resulting from rainfall or a large quantity of melting snow. Sheet erosion commonly, but not always, occurs on land that has a slope.
- the top layer of soil on a hillside washing away down the slope
- washing away of soil from fields of farmland that are freshly cleared our plowed
Rill erosion can be caused by rainfall or the movement of melting snow. Rather than soil washing away in sheets, rill erosion causes the water to cut through the soil, creating small channels on either side that measure no more than 3/10 of an inch in depth. These shallow flow paths through which rainwater flows are an example of rill erosion.
- small channels develop on a dirt road after a steady rain
- small channel-like paths develop in a garden through which rainwater flows
Rill erosion can progress into gully erosion. When the water movement is powerful enough to increase the channels to larger gully pathways greater than 3/10 of an inch, that is when gully erosion occurs. This type of water erosion can be caused by rainfall or melting snow as it moves. It occurs in areas where runoff water accumulates and flows quickly.
- lead to rapid onset flash flooding in torrential rain
- form as channels combine after extended periods of rain or snow melt
Tunnel erosion is the most severe form of water erosion caused by rainfall or melting snow. With this type of erosion, water drips through a hole in the surface, removing soil underneath ground level and carving out a tunnel. It may not be obvious from the surface that there is a hollow area below, at least in the early days after a tunnel forms. Once a tunnel has been in place for a while, the soil on the surface will begin to give way on its own, if it has not already collapsed due to weight being placed on it.
- sinkholes form and cave in where tunnels form
- road collapses can result from tunnel erosion
Coastal erosion is caused by water, but it doesn’t result directly from rainfall. Instead, coastal erosion refers to the impact that wave action has on the shoreline of oceans, seas and gulfs. As waves crash into land on the shore, the sand, rocks, cliffs or soil along the shoreline gets eroded. Increases in sediment in the water greatly amplifies the impact of coastal erosion.
- cracks in shoreline cliffs due to joint compression via wave action
- waves pounding on rocky shoreline breaks off chunks of rock
- cliffs get worn away by particles in seawater.
- carbonic acid in seawater corrodes rocky shoreline
- displacement of shoreline sediment by prevailing current or drift
River and Stream Erosion
Unlike oceans and gulfs, rivers and streams flow between the banks rather than producing crashing waves. River and stream erosion occurs as a result of the impact of moving water on the soil on either side of a flowing body of water. As water flows, the banks of streams, rivers, creeks and other bodies of water can be worn away due to erosion.
- shoreline recession as flowing water melts ground ice (permafrost); called thermal erosion
- creates dangerous environment for aquatic life forms residing in the bodies of water
Wind erosion is erosion caused by wind. It occurs when wind picks up soil from one area, carries it a distance and leaves it somewhere else. It can occur in locations that are windy a lot of the time, as well as places that only occasionally experience wind. The power of wind can move loose soil and also wear down surfaces due to particles carried in the wind.
- sand dunes can be formed or destroyed by wind erosion
- mountains can be worn away by wind erosion
Ice erosion is caused by the movement of glaciers, which are powerful ice formations. The most powerful examples of glacial erosion occurred long ago, during the Ice Age. There are still some places on earth (Greenland and Antarctica) where this phenomenon still occurs. Glaciers can cause erosion to occur as they move across land, picking up and displacing soil and anything else that they go over.
- New York’s finger lakes were cut by glaciers
- Cape Cod and Cape Cod Bay in Massachusetts were carved by glaciers
The Role of Gravity in Erosion
Gravity plays a significant role in erosion, as gravity impacts the forces that cause erosion. For example gravity impacts how water flows, how water moves on or below the surface of the earth, and the action of waves. It also impacts wind and controls how objects move on the surface of the earth. Gravity plays a role in every type of erosion.
- mountain slides illustrate the role of gravity in erosion
- avalanches are also gravity and result in erosion
Learn More About Erosion
Now that you are familiar with some examples of different types of erosion, expand your knowledge of the natural world by studying the difference between weathering and erosion. From there, further explore these two concepts by exploring examples of physical weathering. Chances are that you’ll start to notice examples of erosion and weathering as you go about your everyday activities.