What are the river processes of erosion, transportation, and deposition?

Let's consider a river and its functioning for a moment.

If we were to step into the river, we would find sediment—the tiniest of tiny pieces of rock and soil—moving along in the water. Perhaps the river you are thinking about is muddy, which means there is a lot of sediment in the river. The movement of this sediment and material is transportation. We can see as the river flows past leaves, twigs, and other matter.

Erosion is the process that creates the material being transported; it starts in the riverbed as other sediment wears it down, releasing small pieces to flow down the river bit by bit. It also eats into riverbanks, causing small collapses and large avalanches of material to fall into the water.

And where does the material end up? Sometimes it settles for a short while before being picked up again and placed down in an extensive cycle of transportations, only to be dropped and never moved again at some point. Or maybe we are speaking of silt and mud that eventually flows far out into the ocean and settles there. In this case, the material is created by erosion and is moved by transportation; this process is known as deposition.

River erosion involves the wearing away of the riverbed and banks by the force of flowing water, aided by abrasion, hydraulic action, and corrosion. Transportation refers to the movement of sediment and other materials downstream by the river's flow, utilizing processes such as traction, saltation, suspension, and solution. Deposition occurs when the river loses energy and can no longer transport sediment, leading to the settling of sediment on the riverbed or banks, forming features like river deltas, alluvial fans, and floodplains.