Erosion, transportation and deposition all occur in a river. Moving from the upper course to the lower course, the rates of erosion, transportation and deposition change.
The river picks up sediment and carries it downstream in different ways.
There are four types of transportationTo move objects or people from one place to another.:
Traction - large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the loadThe particles of rock carried by a river. is larger.
Saltation - pebbles are bounced along the river bed, most commonly near the sourceThe place where a river starts in its upper course..
Suspension - lighter sediment is suspended (carried) within the water, most commonly near the mouthThe place where a river meets the sea. of the river.
Solution - the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.