A culvert is a device used to channel water. It may be used to allow water to pass underneath a road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...

, railway, or embankment
Embankment (transportation)
To keep a road or railway line straight or flat, and where the comparative cost or practicality of alternate solutions is prohibitive, the land over which the road or rail line will travel is built up to form an embankment. An embankment is therefore in some sense the opposite of a cutting, and...

. Culverts can be made of many different materials; steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

, polyvinyl chloride
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

 (PVC) and concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 are the most common. Formerly, construction of stone culverts was common.


Culverts come in many shapes and sizes, including round, elliptical, flat-bottomed, pear-shaped, and box. They vary from the small drainage culverts found on highways and driveways to large diameter structures on significant waterways or supporting large water control works. The latter can comprise large engineering projects.

There are three primary materials that culverts are made out of: steel, precast concrete, and polymer (plastic). They can also be built as a hybrid between steel and concrete, for example an open-bottom corrugated steel structure on concrete footings, or a corrugated steel structure with a concrete "collar" around the ends.

When boxes or pipes are placed side-by-side to create a width of greater than twenty feet, the culvert is defined as a bridge in the United States. This is a requirement of the federal bridge inspection standards and ensures that the culvert is inspected on a regular basis.

Minimum energy loss culverts

In the coastal plains of Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

 (North-East Australia), torrential rains during the wet season place a heavy demand on culverts. Further, the natural slope of the flood plains is often very small and little fall (or head loss
Hydraulic head
Hydraulic head or piezometric head is a specific measurement of water pressure above a geodetic datum. It is usually measured as a water surface elevation, expressed in units of length, at the entrance of a piezometer...

) is permissible in the culverts. G.R. McKay and C.J. Apelt developed and patented the design procedure of minimum energy loss culverts waterways which yield small afflux. Apelt presented an authoritative review of the topic (1983) and a well-documented documentary (1994).

A minimum energy loss culvert or waterway is a structure designed with the concept of minimum head loss. The flow in the approach channel is contracted through a streamlined inlet into the barrel where the channel width is minimum, and then it is expanded in a streamlined outlet before being finally released into the downstream natural channel. Both the inlet and outlet must be streamlined to avoid significant form losses. The barrel invert is often lowered to increase the discharge capacity.

The concept of minimum energy loss culverts was developed by Norman Cottman, shire engineer in Victoria (Australia) and by Professor Gordon McKay, University of Queensland (Brisbane, Australia) during the late 1960s. While a number of small-size structures were designed and built in Victoria, some major structures were designed, tested and built in South-East Queensland.


In forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...

, proper use of cross-drainage culverts can improve water quality while allowing forest operations to continue.


Accidents with a culvert can occur if a flood overwhelms it, such as with the Jacobs Creek Flood
Jacobs Creek Flood
The Jacobs Creek Flood, also referred to as the Kansas Turnpike Flash Flood, was a flash flood that occurred on the night of August 30, 2003, southwest of Emporia, KS, on the Kansas Turnpike...

 of 2003, or disrupts the road or railway above it, such as with the Bethungra accident of 1885, which killed seven people.

If a culvert made of steel is not properly galvanized, the culvert can eventually collapse, again disrupting the road or railway above it. This happened at a culvert near Gosford, New South Wales
Gosford, New South Wales
Gosford is a city located on the Central Coast of New South Wales, Australia, approximately 76 km north of the Sydney central business district...

 in 2007, killing five.

See also

  • Borda–Carnot equation
    Borda–Carnot equation
    In fluid dynamics the Borda–Carnot equation is an empirical description of the mechanical energy losses of the fluid due to a flow expansion. It describes how the total head reduces due to the losses. This in contrast with Bernoulli's principle for dissipationless flow , where the total head is a...

  • Drainage
    Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...

  • Low water crossing
    Low water crossing
    A low water crossing provides a bridge when water flow is low. Under high flow conditions, water runs over the roadway and precludes vehicular traffic...

  • Sewer
    Sanitary sewer
    A sanitary sewer is a separate underground carriage system specifically for transporting sewage from houses and commercial buildings to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial wastewater...

  • Siphon
    The word siphon is sometimes used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in the English language today, the word siphon usually refers to a tube in an inverted U shape which causes a liquid to flow uphill, above the surface of the reservoir,...

  • Storm drain
    Storm drain
    A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...

  • Subterranean river
    Subterranean river
    A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth ....

External links

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