Editing Culvert (section)

{{Short description|Structure to channel water past an obstacle}}
{{Use dmy dates|date=August 2019}}
[[File:Leocrain Thunderbolt SuDS culvert.jpg | thumb| Culvert with secure headwall in [[Bromsgrove]], [[England]]]]
[[File:Maakividest truup.JPG|thumb|Stone culvert in [[Haapsalu]], [[Estonia]]]]
[[File:Culvert Picture.jpg|thumb|Steel culvert with a [[plunge pool]] below]]
[[File:Feccia Culvert 2011 SE.jpg|thumb|A multiple culvert assembly in Italy]]
[[File:Pre-cast concrete box culvert.jpg|thumb|[[Precast concrete]] box culvert]]
[[File:Largest culvert in the world at 1.16 kilometres long river monterroso.png | thumb| Large box culvert on [[Rio Monterroso]]]]

A '''culvert''' is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a [[pipe (fluid conveyance)|pipe]], [[reinforced concrete]] or other material. In the [[United Kingdom]], the word can also be used for a longer artificially buried [[watercourse]].<ref>{{cite web|url=https://library.thehumanjourney.net/2322/|title=Thacka Beck Flood Alleviation Scheme, Penrith, Cumbria – Measured Building Survey of Culverts|last=Taylor|first=Karl|year=2010|publisher=[[Oxford Archaeology North]]}}</ref>

Culverts are commonly used both as cross-drains to relieve drainage of [[ditch]]es at the roadside, and to pass water under a road at natural drainage and stream crossings. When they are found beneath roads, they are frequently empty. A culvert may also be a bridge-like structure designed to allow vehicle or pedestrian traffic to cross over the waterway while allowing adequate passage for the water. Dry culverts are used to channel a [[fire hose]] beneath a [[noise barrier]] for the ease of [[firefighter|firefighting]] along a highway without the need or danger of placing hydrants along the roadway itself.

Culverts come in many sizes and shapes including round, elliptical, flat-bottomed, open-bottomed, pear-shaped, and box-like constructions. The culvert type and shape selection is based on a number of factors including requirements for hydraulic performance, limitations on upstream water surface elevation, and roadway embankment height.<ref name="Center 1998">Turner-Fairbank Highway research Center (1998). "Hydraulic Design of Highway Culverts" (PDF), Report #FHWA-IP-85-15 US Department of Transportation, Federal Highway Administration, McLean, Virginia.</ref>

The process of removing culverts to restore an open-air watercourse is known as [[Daylighting (streams)|daylighting]]. In the UK, the practice is also known as deculverting.<ref>
{{cite journal
 | last =Wild
 | first =Thomas C.
 | date =2011
 | title =Deculverting: reviewing the evidence on the 'daylighting' and restoration of culverted rivers.
 | journal =Water and Environment Journal
 | doi=10.1111/j.1747-6593.2010.00236.x
 | volume=25
 | issue =3
 | pages=412–421
 | s2cid =111280203
}}
</ref>