Runoff (hydrology)
Runoff is the flow of
Background
The
The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence the climate system.
The evaporative phase of the cycle purifies water because it causes salts and other solids picked up during the cycle to be left behind. The condensation phase in the atmosphere replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It also reshapes the geological features of the Earth, through processes including erosion and sedimentation. The water cycle is also essential for the maintenance of most life and ecosystems on the planet.
Surface runoff
Surface runoff is a major component of the water cycle. It is the primary agent of soil erosion by water.[6][7] The land area producing runoff that drains to a common point is called a drainage basin.
Runoff that occurs on the ground surface before reaching a channel can be a nonpoint source of pollution, as it can carry human-made contaminants or natural forms of pollution (such as rotting leaves). Human-made contaminants in runoff include petroleum, pesticides, fertilizers and others.[8] Much agricultural pollution is exacerbated by surface runoff, leading to a number of down stream impacts, including nutrient pollution that causes eutrophication.
In addition to causing water erosion and pollution, surfaceUrban runoff
Channel runoff
Model
A
A well known runoff model is the linear reservoir, but in practice it has limited applicability.
The runoff model with a non-linear reservoir is more universally applicable, but still it holds only for catchments whose surface area is limited by the condition that the rainfall can be considered more or less uniformly distributed over the area. The maximum size of the watershed then depends on the rainfall characteristics of the region. When the study area is too large, it can be divided into sub-catchments and the various runoff hydrographs may be combined using flood routing techniques.Curve number
References
- ^ "The Water Cycle (PNG) | U.S. Geological Survey". www.usgs.gov. Retrieved 2024-04-24.
- ^ "Water Cycle | Science Mission Directorate". science.nasa.gov. Archived from the original on 2018-01-15. Retrieved 2018-01-15.
- ^ Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, and O. Zolina, 2021: Water Cycle Changes. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US, pp. 1055–1210, doi:10.1017/9781009157896.010.
- ^ Arias, P.A., N. Bellouin, E. Coppola, R.G. Jones, G. Krinner, J. Marotzke, V. Naik, M.D. Palmer, G.-K. Plattner, J. Rogelj, M. Rojas, J. Sillmann, T. Storelvmo, P.W. Thorne, B. Trewin, K. Achuta Rao, B. Adhikary, R.P. Allan, K. Armour, G. Bala, R. Barimalala, S. Berger, J.G. Canadell, C. Cassou, A. Cherchi, W. Collins, W.D. Collins, S.L. Connors, S. Corti, F. Cruz, F.J. Dentener, C. Dereczynski, A. Di Luca, A. Diongue Niang, F.J. Doblas-Reyes, A. Dosio, H. Douville, F. Engelbrecht, V. Eyring, E. Fischer, P. Forster, B. Fox-Kemper, J.S. Fuglestvedt, J.C. Fyfe, et al., 2021: Technical Summary. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US, pp. 33−144. doi:10.1017/9781009157896.002.
- ^ "runoff". National Geographic Society. 2011-01-21. Archived from the original on 2021-01-28. Retrieved 2021-02-19.
- ^ Ronnie Wilson, The Horton Papers (1933)
- ^ Keith Beven, Robert E. Horton's perceptual model of infiltration processes, Hydrological Processes, Wiley Intersciences DOI 10:1002 hyp 5740 (2004)
- ISBN 0-07-235053-9
- ^ "Impact of Water Runoff from Streets and Yards". Highlands Ranch, CO: Highlands Ranch Metro District. Retrieved 30 August 2021.
- ^ "Runoff (surface water runoff)". USGS Water Science School. Reston, VA: U.S. Geological Survey (USGS). 2018-06-06.
- ISBN 1-57278-039-8. Chapter 1.
- ^ Schueler, Thomas R. (2000) [initial publ. 1995]. "The Importance of Imperviousness". In Schueler; Holland, Heather K. (eds.). The Practice of Watershed Protection. Ellicott City, MD: Center for Watershed Protection. pp. 1–12. Archived from the original (pdf) on 2014-03-27. Retrieved 2014-12-24.
- ^ United States Department of Agriculture (1986). Urban hydrology for small watersheds (PDF). Technical Release 55 (TR-55) (Second ed.). Natural Resources Conservation Service, Conservation Engineering Division.