Editing Soil erosion (section)

===Roads and human impact===
[[File:Erosion pollution.jpg|thumb|Erosion polluted the Kasoa highway after downpour in Ghana.]]
[[Human impact on the environment|Human Impact]] has major effects on erosion processes—first by denuding the land of vegetative cover, altering drainage patterns, and compacting the soil during construction; and next by covering the land in an impermeable layer of asphalt or concrete that increases the amount of surface runoff and increases surface wind speeds.<ref>{{cite book|author=Nîr, Dov|title=Man, a Geomorphological Agent: An Introduction to Anthropic Geomorphology|publisher=Springer|year=1983|isbn=978-90-277-1401-5|pages=121–122|url=https://books.google.com/books?id=3HSCQvZ7U2kC&pg=PA121}}</ref> Much of the sediment carried in runoff from urban areas (especially roads) is highly contaminated with fuel, oil, and other chemicals.<ref>{{cite book|author=Randhir, Timothy O.|title=Watershed Management: Issues and Approaches|publisher=IWA Publishing|year=2007|isbn=978-1-84339-109-8|page=56|url=https://books.google.com/books?id=PNBlSPdu0JAC&pg=PA56}}</ref> This increased runoff, in addition to eroding and degrading the land that it flows over, also causes major disruption to surrounding watersheds by altering the volume and rate of water that flows through them, and filling them with chemically polluted sedimentation. The increased flow of water through local waterways also causes a large increase in the rate of bank erosion.<ref>{{cite book|author=James, William|chapter=Channel and habitat change downstream of urbanization|editor=Herricks, Edwin E.|editor2=Jenkins, Jackie R.|title=Stormwater Runoff and Receiving Systems: Impact, Monitoring, and Assessment|publisher=CRC Press|year=1995|isbn=978-1-56670-159-4|page=105|chapter-url=https://books.google.com/books?id=X0xt9HZbyToC&pg=PA105}}</ref>