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A floodway is a 
A floodway is a flood plain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
crossing for a road, built at or close to the natural ground level. It is similar to a causeway
A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet Tra ...
, but crosses a shallow depression that is subject to flooding, rather than a waterway or tidal water.
They are designed to be submerged under water, but withstand such conditions. Typically floodways are used when the flood frequency or time span is minimal, traffic volumes are low, and the cost of a bridge is uneconomic – in most cases, in rural areas.
See also
* Flood control channel *Glossary of road transport terms
Terminology related to road transport—the transport of passengers or goods on paved (or otherwise improved) routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single co ...
* Low water crossing
Notes
* * *External links
Flood control Transportation engineering Rivers Hydraulic engineering {{road-stub