erosion

The geologic process in which the surface of the earth, including soil, bedrock, and rock fragments, is degraded by natural processes. There are multiple processes by which these earth materials can be eroded including eolian erosion (wind), fluvial (rivers and streams), marine (ocean waves), and glacial. These processes break down rocks in their primary locations and then transport them to secondary locations. Geologic formations such as canyons and mesas are formed by the erosion of bedrock by natural forces. Erosion in the Southwest, in addition to many regions around the planet, has been exacerbated by human impact, such as overuse of sensitive areas; extraction of natural resources, inlcuding water; and land management practices at a large scale.