Attrition

Attrition occurs when the sediment particles themselves collide. Pieces chip off, so the particles become smaller, smoother and rounder. For example, angular fragments released from a cliff can become rounded pebbles after repeated collisions.

Attrition: transported particles collide with one another and chip or break apart. They become smaller, smoother and more rounded.

Attrition changes the load itself. Transported fragments collide with one another and the bed, becoming smaller, smoother and more rounded. Unlike abrasion, its main result is the wearing down of the particles rather than the channel.

Attrition happens when transported particles collide with one another. Edges chip off, so the particles become smaller, smoother and more rounded. Attrition changes the sediment load rather than directly scraping the river bank or cliff.