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 Track in the Somerset Levels, England, that dates from the Neolithic age. Timber causeways may also be described as both boardwalks and bridges.The Julia Tuttle Causeway, one of the major arteries connecting Miami and Miami Beach in FloridaAfsluitdijk with the North Sea on the left and the IJsselmeer on the rightAerial view of the Lucin Cutoff trestle before removal. The 1950s causeway can be seen to the right of the trestle.The causeway to Antelope Island in the Great Salt Lake, UtahThe Johor–Singapore Causeway is an important road which connects Singapore to MalaysiaThe Sorell Causeway in Tasmania, AustraliaLake Pontchartrain Causeway bridge in New OrleansCauseway across Colwyn Bay Beach, Wales, United KingdomThe King Fahd Causeway from satellite photoCauseway in St. George's, BermudaCauseway that connects Victor Harbor with Granite Island in Australia (Completed in 1867) 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 Track in the Somerset Levels, England, that dates from the Neolithic age. Timber causeways may also be described as both boardwalks and bridges. When first used, the word appeared in a form such as 'causey way' making clear its derivation from the earlier form 'causey'. This word seems to have come from the same source by two different routes. It derives ultimately, from the Latin for heel, calx, and most likely comes from the trampling technique to consolidate earthworks. Originally, the construction of a causeway utilised earth that had been trodden upon to compact and harden it as much as possible, one layer at a time, often by slaves or flocks of sheep. Today, this work is done by machines. The same technique would have been used for road embankments, raised river banks, sea banks and fortification earthworks. The second derivation route is simply the hard, trodden surface of a path. The name by this route came to be applied to a firmly-surfaced road. It is now little-used except in dialect and in the names of roads which were originally notable for their solidly-made surface. The 1911 Encyclopædia Britannica states 'causey, a mound or dam, which is derived, through the Norman-French caucie (cf. modern chaussée), from the late Latin via calciata, a road stamped firm with the feet (calcare, to tread).' The word is comparable in both meanings with the French chaussée, from a form of which it reached English by way of Norman French. The French adjective, chaussée, carries the meaning of having been given a hardened surface, and is used to mean either paved or shod. As a noun chaussée is used on the one hand for a metalled carriageway, and on the other for an embankment with or without a road. Other languages have a noun with similar dual meaning. In Welsh, it is sarn. The Welsh is relevant here, as it also has a verb, sarnu, meaning to trample. The trampling and ramming technique for consolidating earthworks was used in fortifications and there is a comparable, outmoded form of wall construction technique, used in such work and known as pisé, a word derived not from trampling but from ramming or tamping. The Welsh word 'cawsai' translates directly to the English word 'causeway'; it is possible that, with Welsh being a lineal linguistic descendant of the original native British tongues, the English word derives from the Welsh. A transport corridor that is carried instead on a series of arches, perhaps approaching a bridge, is a viaduct; a short stretch of viaduct is called an overpass. The distinction between the terms causeway and viaduct becomes blurred when flood-relief culverts are incorporated, though generally a causeway refers to a roadway supported mostly by earth or stone, while a bridge supports a roadway between piers (which may be embedded in embankments). Some low causeways across shore waters become inaccessible when covered at high tide. The Aztec city-state of Tenochtitlan had causeways supporting roads and aqueducts. One of the oldest engineered roads yet discovered is the Sweet Track in England. Built in 3807 or 3806 BC, the track was a walkway consisting mainly of planks of oak laid end-to-end, supported by crossed pegs of ash, oak, and lime, driven into the underlying peat. The modern embankment may be constructed within a cofferdam: two parallel steel sheet pile or concrete retaining walls, anchored to each other with steel cables or rods. This construction may also serve as a dyke that keeps two bodies of water apart, such as bodies with a different water level on each side, or with salt water on one side and fresh water on the other. This may also be the primary purpose of a structure, the road providing a hardened crest for the dike, slowing erosion in the event of an overflow. It also provides access for maintenance as well perhaps, as a public service.