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Rivers (Erosion (Abrasion (When the load carried by the river repeatedly…
Rivers
Erosion
Abrasion
When the load carried by the river repeatedly hits the bed or banks dislodging particles into the flow of the river
Hydraulic action
The force of the water hitting the river bed and banks.This is the most effective when the water is moving fast and when there is a lot of it
Attrition
When stones carried by the river knock against each other,Gradually making the stones smaller and more rounded
Solution
When the river flows over limestone or chalk,the rock is slowly dissolved.This is because it is soluble in mildly acidic river water
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Transportation
Saltation
pebbles are bounced along the river bed, most commonly near the source.
Suspension
lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.
Traction
large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.
Solution
the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
The size and amount of load that can be carried will depend of the river's rate of flow - It's velocity
Deposition
Larger rocks tend to be deposited in the upper course of a river.They are only transported for very short distances, mostly by traction,during periods of high flow
A large amount of deposition occurs at the river mouth,where the interaction with the tides,along with the very gentle gradient,greatly reduces the rivers velocity.
Finer sediment is carried further downstream,mostly held in suspension. This material will be deposited on the river banks,Where velocity is slowed by friction
