Author
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Flanagan, Dennis |
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Huang, Chi Hua |
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 6/29/2016 Publication Date: 11/1/2016 Citation: Flanagan, D.C., Huang, C. 2016. Erosion. In: Singh, V.P., ed. Handbook of Applied Hydrology, 2nd Edition. New York: McGraw-Hill Education, New York. 64:1-6. Interpretive Summary: Technical Abstract: Erosion is the process of detaching soil particles and transporting them to another location. Forces applied to the soil can cause its movement. For example, the gravitational force causes landslides and debris flows and plowing of the soil by tillage implements also moves soil particles from one location to another. Most commonly known erosion events are those caused by forces of wind and water although the gravitational force plays the inherent role in either causing or preventing erosion to occur. Wind erosion occurs when wind speed exceeds a critical threshold level causing soil particle movement directly form the wind power or indirectly by abrasion from particles already in motion. Erosion by water is typically by raindrop impact or by concentrated water flow on a soil surface. The momentum of water drops can result in soil compaction and ejection of water and sediment sprays (splash) at the point of impact. Water flow on a soil surface may coalesce into small channels or rills. When enough water is flowing in a rill, flow shear forces will act to detach soil from the channel bottom and sides. In larger channels, similar detachment due to flow shear forces can also occur, as well as additional soil loss from other processes including bank sidewall sluffing and headcutting. A number of practices are recommended to reduce or prevent erosion, including use of mulch or plant residues to protect the soil surface, terraces to reduce slope length and steepness, and grade control structures to safely transport water flow to lower elevations. |
