Alluvial plain


Alluvial plain

An alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms. A floodplain is part of the process, being the smaller area over which the rivers flood at a particular period of time, whereas the alluvial plain is the larger area representing the region over which the floodplains have shifted over geological time.

As the highlands erode due to weathering and water flow the sediment from the hills is transported to the lower plain. Various creeks will carry the water further to a river, lake, bay, or ocean. As the sediments are deposited during flood conditions in the floodplain of a creek, the elevation of the floodplain will be raised. As this reduces the channel floodwater capacity, the creek will over time seek new, lower paths, forming meanders (a curving sinuous path). The leftover higher locations, typically natural levees at the margins of the flood channel, will themselves be eroded by lateral stream erosion and from local rainfall and possibly wind transport if the climate is arid and does not support soil-holding grasses. These processes over geologic time will form the plain - a region with little relief (local changes in elevation), yet with a constant but small slope.

Examples

*Mississippi River alluvial plain [ [http://tapestry.usgs.gov/features/45mississippi.html Mississippi River alluvial plain] ]
*Punjab alluvial plain [ [http://www.britannica.com/eb/article-9061915/Punjab-Plain Punjab Plain] , Encyclopedia Britannica]
*List of alluvial sites in Switzerland

ee also

* Alluvial desert
* Alluvial fan
* Alluvium
* River delta

References


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Look at other dictionaries:

  • alluvial plain — noun a flat resulting from repeated deposits of alluvial material by running water • Syn: ↑alluvial flat • Hypernyms: ↑flat * * * noun 1. : a level or gently sloping flat or a slightly undulating land surface resulting from extensive deposition… …   Useful english dictionary

  • alluvial plain — sąnašinė lyguma statusas T sritis ekologija ir aplinkotyra apibrėžtis Iš aukštutinės upės dalies paviršinio nuotėkio atneštų sąnašų susidariusi lyguma. atitikmenys: angl. alluvial plain vok. Alluvialebene, f; Aufschüttungsebene, f rus.… …   Ekologijos terminų aiškinamasis žodynas

  • alluvial plain —     a) A large assemblage of fluvial landforms (braided streams, terraces, etc.,) that form low gradient, regional ramps along the flanks of mountains and extend great distances from their sources (e.g., High Plains of North America.    SW.… …   Glossary of landform and geologic terms

  • alluvial plain — /əluviəl ˈpleɪn/ (say uhloohveeuhl playn) noun a river flood plain with a surface covered by alluvial deposits …   Australian English dictionary

  • alluvial plain — noun A plain formed by the deposition of sediment from the periodic flooding of a river. Syn: floodplain …   Wiktionary

  • alluvial plain —    A plain formed by the deposition of water borne sediments [16] …   Lexicon of Cave and Karst Terminology

  • alluvial plain — a level or gently sloping surface formed of sediments laid down by streams, generally during flooding. [1955 60] * * * …   Universalium

  • alluvial plain remnant —    An erosional remnant of an alluvial plain which retains the surface form and alluvial deposits of its origin but was not emplaced by, and commonly does not grade to a present day stream or drainage network.    Compare: alluvial plain,… …   Glossary of landform and geologic terms

  • Mississippi Alluvial Plain —   Mississippi Delta …   Wikipedia

  • Plain — s.Plains occur as lowlands and at the bottoms of valleys but also on plateaus at high elevations. They may have been formed from flowing lava, deposited by water, ice or wind, or formed by erosion by these agents from hills and mountains.Plains… …   Wikipedia


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