River processes

Name four transportation processes in rivers.

• Solution

• Suspension

• Saltation

• Traction

Transportation by solution

Soluble minerals such as calcium carbonate (limestone) are dissolved from soil or rock and carried along within the river

Transportation by suspension

Small particles like clay and silt are suspended in the river flow and carried long distances.

Transportation by saltation

Smaller pebbles and gravels are bounced along the river bed. This requires a more energetic river with higher velocity.

Transportation by traction

Larger pebbles and rocks are rolled along the river bed. This requires a river with a lot of energy.

Name four erosional processes in rivers.

• Hydraulic action

• Abrasion

• Attrition

• Solution

Erosion by hydraulic action

Water crashes into gaps in the soil/rock, compressing the air and forcing particles apart. Eventually causes cracks and widens them.

Erosion by abrasion

Particles carried within the river such as rocks and pebbles grind along the bank and bed of the river with a sandpapering effect.

Erosion by attrition

Rocks carried within the river smash into one another, wearing down into smaller and more rounded particles.

Erosion by solution

Soluble minerals in rock and soil are dissolved in the river water.

Deposition

• A river which no longer has enough energy to carry the particles within it must deposit its load.

• Larger sediment is deposited first, as they require more energy to transport, whereas smaller particles can be carried further.