An alluvial plain is a plain (a largely 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 a meander (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.
The Glossary of Landform and Geologic Terms, maintained by the United States' National Cooperative Soil Survey (NCSS), defines an "alluvial plain" as "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)" Use of "alluvial plain" as a general, informal term for a broad flood plain or a low-gradient delta is explicitly discouraged. The NCSS glossary instead suggests "flood plain".[1]
Alluvial plains have similar traits to a river delta; however, the river delta will flow into a larger body of water. Alluvial plains generally lack this.
^"Glossary of Landform and Geologic Terms" (PDF). National Soil Survey Handbook—Part 629. National Cooperative Soil Survey. April 2013. Retrieved 1 March 2023.
^Mississippi River alluvial plain 2007-07-05 at the Wayback Machine
^Santa Clara Valley Groundwater Basin, East Bay Plain Subbasin 2020-12-25 at the Wayback Machine
Wikimedia Commons has media related to Alluvial plains.
December 20, 2023
alluvial, plain, glacial, feature, outwash, plain, alluvial, plain, plain, largely, flat, landform, created, deposition, sediment, over, long, period, time, more, rivers, coming, from, highland, regions, from, which, alluvial, soil, forms, floodplain, part, pr. For the glacial feature see Outwash plain An alluvial plain is a plain a largely 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 Floodplain centre within the alluvial plain of the Waimakariri River New Zealand part of the Canterbury Plains A small incised alluvial plain from Red Rock Canyon State Park California 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 a meander 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 The Glossary of Landform and Geologic Terms maintained by the United States National Cooperative Soil Survey NCSS defines an alluvial plain as 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 Use of alluvial plain as a general informal term for a broad flood plain or a low gradient delta is explicitly discouraged The NCSS glossary instead suggests flood plain 1 Alluvial plains have similar traits to a river delta however the river delta will flow into a larger body of water Alluvial plains generally lack this Examples editBaetic Depression in Andalusia Spain Canterbury Plains Southland Plains and Waikato Plains in New Zealand Chianan Plain in Taiwan Lower Danubian Plain Bulgaria and Romania Indo Gangetic Plain and Punjab in India Pakistan and Bangladesh 2 Iskar river valleys in Bulgaria Mekong Delta in Vietnam Mesaoria in Cyprus Mesopotamia in Iraq Mississippi Alluvial Plain Oxnard Plain and Laguna de Santa Rosa in the United States 3 Multiple sites in Switzerland North China Plain in China Palakaria Valley in Bulgaria Po Valley in Italy Rhine Meuse Scheldt in the Netherlands Santa Clara Valley in San Jose California 4 Struma Valley in Bulgaria Tempisque River plain in Costa Rica Tundzha valleys in Bulgaria Upper Thracian Plain in BulgariaSee also editAlluvial fan Alluvium Coastal plain Desert pavement River deltaReferences edit Glossary of Landform and Geologic Terms PDF National Soil Survey Handbook Part 629 National Cooperative Soil Survey April 2013 Retrieved 1 March 2023 Punjab Plain Encyclopaedia Britannica Mississippi River alluvial plain Archived 2007 07 05 at the Wayback Machine Santa Clara Valley Groundwater Basin East Bay Plain Subbasin Archived 2020 12 25 at the Wayback Machine nbsp Wikimedia Commons has media related to Alluvial plains Retrieved from https en wikipedia org w index php title Alluvial plain amp oldid 1188219012, wikipedia, wiki, book, books, library,
