Fluvial (river) processes Flashcards
(15 cards)
What is erosion?
Erosion is the process by which a river wears away the land.
Erosion shapes the river channel and is a key geological process.
What are the four main types of erosion?
- Hydraulic action
- Abrasion
- Attrition
- Solution
Each type of erosion contributes differently to shaping the river channel.
Define hydraulic action in the context of river erosion.
The force of the water breaks rock particles away from the riverbed and banks.
Hydraulic action is a powerful erosive force in rivers.
What is abrasion in river erosion?
Rocks wear down the riverbed and banks in a sandpapering action.
Abrasion contributes to the smoothness of riverbed surfaces.
Explain attrition.
Rocks carried by the river smash together and break into smaller, smoother pieces.
Attrition helps in creating rounded river pebbles.
What is meant by solution in erosion?
Soluble particles are dissolved into the river water.
Solution is a chemical process affecting the river’s mineral content.
What does transportation refer to in the context of rivers?
Transportation is the movement of eroded material downstream.
This process is crucial for shaping river landscapes.
List the four ways rivers transport material.
- Traction
- Saltation
- Suspension
- Solution
Each method of transportation varies by the size and weight of the materials.
Define traction in river transportation.
Large boulders and rocks are rolled along the riverbed.
Traction is effective for larger sediment types.
What is saltation?
Small pebbles and stones are bounced along the riverbed.
Saltation allows for the movement of smaller particles without fully lifting them off the riverbed.
What does suspension mean in river transportation?
Fine material is carried within the water.
Suspension is common for very small particles that remain afloat in the river.
What is the solution method in river transportation?
Dissolved materials are carried along by the river.
This method includes minerals and nutrients that are soluble in water.
What occurs during deposition in a river?
A river loses energy and drops the material it has been carrying.
Deposition is essential for forming new landforms along riverbanks.
When does deposition typically happen?
When the river slows down, such as when it enters a lake or the sea or flows over a flat plain.
Changes in river velocity are critical for deposition to occur.
How does deposition contribute to the river’s landscape?
Deposition forms various landforms and contributes to the river’s ever-changing landscape.
This process is key to the natural evolution of river systems.
