Fluvial Processes

Transportation

• There are four types of transportation in rivers, as shown on the accompanying diagram.
• Traction is the rolling of larger rocks along the river floor.
• Saltation is the hopping/bouncing of smaller rocks and pebbles across the river floor.
• Very small pieces of sediment are carried through suspension.
• Solution carries dissolved minerals in the water.
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Erosion

• There are four types of erosion that take place in rivers:
• Abrasion - the force of sand and pebbles in the river scraping away at the channel.
• Attrition - the wearing away of rocks in the river by hitting off one another.
• Hydraulic action - the wearing away of rocks by the force of the water. This can also occur through the compression of air in small gaps by water.
• Solution - the chemical breakdown of rock by water.
• Rocks can also be broken down by physical and chemical weathering processes.

Factors affecting rates of fluvial processes

• Velocity and discharge of the river affect how much sediment a river can carry.
• Relief controls the velocity of the river.
• Climate affects the amount of precipitation that falls and how much water is in the river.
• Sediment size can play a role in the landforms formed, i.e. larger sediment is more difficult for the river to carry.
• Human activity can play a large role in modifying river processes.