
A small culvert under a pedestrian walkway.
A 'culvert' is a conduit used to enclose a flowing body of
water. It may be used to allow water to pass underneath a
road,
railway, or
embankment for example. Culverts can be made of many different materials;
steel,
polyvinyl chloride (PVC) and
concrete are the most common.
Problems
In the
Pacific Northwest of the
United States, it has been found that many culverts impede upstream migration by
salmon. Research is being carried out to determine how culverts can be adapted to make it easier for salmon and other fish to pass through them against the current.
When used to transport water in streams or rivers, the capacity of the culvert(s) is generally lower than the capacity of the river itself. This results in the water overflowing the road surface during heavy flow events. If this is by design, the result is referred to as a
low water crossing. When this is unacceptable, the culvert-based crossing must be replaced by a more expensive system such as a
bridge.
Also, debris and trash that is flowing through the water may get stuck in the culvert, decreasing the flow of water even further.
Culverts are also seen as unsightly compared to a bridge.
See also
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Drainage
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Sewer
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Siphon
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Storm drain
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Low water crossing
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Subterranean river
Reference
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Oxford English Dictionary, ISBN 0-19-861212-5
External links
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Culvert Technology May Help Young Salmon Muscle Their Way Upstream — Article about the impact of culverts on salmon migration
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Culvert fact sheet — Information produced by Canadian Department of Fisheries and Oceans
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Bottomless Culvert Scour Study —
FHWA culvert research
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Design of Road Culverts for Fish Passage Washington Department of Fish and Wildlife guide to designing and constructing fish migration friendly culverts
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Culverts 2007 TechnoLogismiki Culverts software program based on FHWA culvert research