Erosion can result in minor inconveniences or total destruction. Severe erosion removes the earth from beneath bridges, roads and foundations of structures adjacent to streams. By undercutting it can lead to increased rockfall and landslide hazard. The deposition of material can block culverts, aggravate flooding, destroy crops and lawns by burying them, and reduce the capacity of water reservoirs as the deposited materials displace water. Severe erosion from man-made alterations of the drainage systems resulted in a large gully in Douglas County.
Erosion may adversely affect the respiratory functions of humans and livestock by reducing air quality from airborne dust, as in the famous Dust Bowl. Furthermore, there is an increased risk of pollution to surface and ground waters due to use of nutrients and pesticides from agricultural and residential treatment of vegetation.
Human activities greatly influence the rate and extent of erosion and deposition. Stripping the land surface of vegetation, altering natural drainages, and rearranging the earth through construction of highways, subdivision development, farmland preparation, and modification of drainage channels for water control projects are significant factors in increased erosion and deposition. All the geologic processes that make available more material for erosion and deposition tend to increase the rates of each process. This is particularly true for landslides, mud flows, debris flows, earthflows, rock falls, and physical and chemical weathering. These processes also involve erosion and deposition while frequently make more material vulnerable to erosion.