Editing Levee (section)

{{Short description|Ridge or wall to hold back water}}
{{Other uses}}
{{Use dmy dates|date=March 2020}}
{{Use American English|date=June 2021}}
[[File:River Levee Cross Section Figure.svg|thumb|Components of an artificial levee:
{{ordered list
| 1 = Design high water level (HWL)
| 2 = Low water channel
| 3 = Flood channel
| 4 = Riverside slope
| 5 = Riverside banquette
| 6 = Levee crown
| 7 = Landside slope
| 8 = Landside banquette
| 9 = Berm
| 10 = Low water revetment
| 11 = Riverside land
| 12 = Levee
| 13 = Protected lowland
| 14 = River zone
}}]]
[[File:Sacramento River Levee.jpg|thumb|The side of a levee in [[Sacramento, California|Sacramento]], [[California]]]]

A '''levee''' ({{IPAc-en|ˈ|l|ɛ|v|i}} or {{IPAc-en|ˈ|l|ɛ|v|eɪ}}),{{efn|Sometimes {{gloss|levée}}}}<ref>{{cite OED|levee|39369470}}</ref> '''dike''' ([[American English]]), '''dyke''' ([[British English]]; see [[American and British English spelling differences#Miscellaneous spelling differences|spelling differences]]), '''embankment''', '''floodbank''', or '''stop bank''' is an elevated [[ridge]], natural or artificial, alongside the [[river banks|banks]] of a [[river]], often intended to [[flood control|protect against flooding]] of the area adjoining the river. It is usually [[soil|earthen]] and often runs [[parallel (geometry)|parallel]] to the course of a river in its [[floodplain]] or along low-lying coastlines.<ref>{{Cite journal | title=Levees and Other Raised Ground | author=Henry Petroski  | journal=American Scientist | year=2006 | volume=94 | issue=1 | pages=7–11| doi=10.1511/2006.57.7 }}</ref>

Naturally occurring levees form on river [[floodplain]]s following flooding. Sediment and [[alluvium]] are [[deposition (geology)|deposited]] on the banks and settle, forming a ridge that increases the river channel's capacity. Alternatively, levees can be artificially constructed from [[fill dirt|fill]], designed to regulate water levels. In some circumstances, artificial levees can be [[environmental degradation|environmentally damaging]].<ref>{{Cite web |title=Flood risk reduction with multiple benefits: more space for the river |url=https://www.preventionweb.net/news/flood-risk-reduction-multiple-benefits-more-space-river |access-date=2023-01-22 |website=www.preventionweb.net |date=6 May 2022 |language=en}}</ref>

Ancient civilizations in the [[Indus Valley civilisation|Indus Valley]], ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters,<ref>{{Cite web |date=11 February 2021 |title=A Look at Preventing Levee Erosion |url=https://www.fema.gov/case-study/look-preventing-levee-erosion |access-date=28 June 2023 |website=[[Federal Emergency Management Agency]]}}</ref> such as the catastrophic [[2005 levee failures in Greater New Orleans]] that occurred as a result of [[Hurricane Katrina]].