What is the term for the process where pebbles transported by a river rub against each other and erode into smaller particles?

Attrition is the term that describes the process where river pebbles and larger particles collide with one another during transport, leading to their gradual erosion into smaller pieces. This occurs because as these materials are carried along by the flowing water, they are subjected to consistent impacts and friction against each other. Over time, this mechanical weathering reduces the size of the particles, smoothing their surfaces and breaking them down further.

Understanding this process is essential as it highlights how rivers actively shape the landscape. While erosion refers generally to the wearing away of land and can include various processes, attrition specifically focuses on the interactions among materials already in motion. Hydraulic action pertains to the force of water impacting the banks of a river, while transport refers to the movement of sediment but does not specify the size-reducing interactions that occur through attrition.