Where the sheer force of the water erodes the stones bed and banks of the river.
Where stones in transport are thrown into the bed and banks, eroding them.
Where weak acids within the water react with the rocks and bed of the river.
Where stones in transport are thrown into one another.
Minerals are dissolved in water and carried along in solution.
Fine light material is carried along in water (suspended).
Small pebbles and stones bounce along the river bed.
Large boulders or rocks are rolled along the river bed.
When a river loses energy, it will drop or deposit some of the material it's carrying,
Deposition may take place when a river enters and area of shallow water or when the volume of water decreases, for example after a flood or during times of drought. It can also occur where wetted perimeter increases relative to the cross sectional area.
Flocculation can also occur- this is where clay particles bond together, I creasing their mass and therefore sink to the river or sea bed.