erosion

The most powerful forms of erosion are water, consisting of sea waves and currents, rivers, and rain; ice, in the form of glaciers; and wind, hurling sand fragments against exposed rocks and moving dunes along. People also contribute to erosion by poor farming practices and the cutting down of forests, which can lead to increased overland water run-off.

There are several processes of river erosion including hydraulic action, corrasion, attrition, and solution.