River Erosion

Processes:

Corrasion, (abrasion) is the grinding of rock fragments carried by the river against the bed and banks of the river. This action causes the channel to widen and deepen. This grinding is most powerful in flood time when large fragments of rock are carried along in the river bed.

Attrition

Attrition is the collision of rock fragments in the water against one another. The rock particles are broken into smaller pieces and become smoother the longer the process continues.

Solution

Solution (corrosion) is the process by which river water reacts chemically with soluble minerals in the rocks and dissolves them. An additional process is also at work caused by the force of the water itself known as Hydraulic action. In this rocks are dragged away from the bed and banks by the force of the running water.  When water from a fast moving stream enters minute cracks in a rock, the pressure exerted weakens and eventually breaks up the rock