Why do rivers deposit sediment?
Deposition is when material transported by a river is dropped. Material deposited by a river is known as sediment. The larger the material, the higher the velocity needed to transport it. Therefore, when velocity decreases, the large boulders are the first to be deposited. Whereas, finer materials, such as clay particles are the last to be deposited.
Deposition occurs whenever a river loses energy and velocity falls. This can be when:
Deposition leads to the formation of a range of landforms in the lower course of the river.
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