Coastal lagoons fronted by barrier spits typically have entrances that migrate through time. A spit is a deposition Landform found off Coasts. At one end spits connect to land while at the far end they exist in open water Here, the entrance has been fixed by jetty construction. Carlsbad, CA, USA, April 1998.

A jetty is any of a variety of structures used in river, dock, and maritime works which are generally carried out in pairs from river banks, or in continuation of river channels at their outlets into deep water; or out into docks, and outside their entrances; or for forming basins along the sea-coast for ports in tideless seas. "Riverine" redirects here For the use of that term in Maritime geography, see there A dock (from Dutch 'dok' is a man-made feature involved in the handling of boats or ships This article is about the body of water For other uses see SEA and Seas. ||-||-|-||-||-||-||-||-||-|} A port is a facility for receiving Ships and transferring cargo Characteristics A tide is a repeated cycle of sea level changes in the following stages Over several hours the water rises or advances up a beach in the flood The forms and construction of these jetties are as varied as their uses; for though they invariably extend out into water, and serve either for directing a current or for accommodating vessels, they are sometimes formed of high open timber-work, sometimes of low solid projections, and occasionally only differ from breakwaters in their object. A current, in a River or Stream, is the Flow of Water influenced by Gravity as the water moves Downhill to reduce its Breakwaters are structures constructed on coasts as part of coastal defence or to protect an anchorage from the effects of Weather and Longshore drift. The term derived from the French word jetée, "to throw", and signifies something thrown out. French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people

For regulating rivers

Formerly jetties of timber-work were very commonly extended out, opposite one another, from each bank of a river, at intervals, to contract a wide channel, and by concentration of the current to produce a deepening of the central channel; or sometimes mounds of rubble stone, stretching down the foreshore from each bank, served the same purpose. Physical geography, a channel is the physical confine of a River, slough or ocean Strait consisting of a bed and banks As, however, this system occasioned a greater scour between the ends of the jetties than in the intervening channels, and consequently produced an irregular depth, it has to a great extent been superseded by longitudinal training works, or by dipping cross dikes pointing somewhat upstream (see River engineering). LeveeEmbankmentDitch A dike (or dyke) levee, levée, embankment, floodbank or stopbank is a natural or artificial River engineering is the process of planned human intervention in the course characteristics or flow of a River with the intention of producing some defined benefit

For berthing at docks

Where docks are given sloping sides, openwork timber jetties are generally carried across the slope, at the ends of which vessels can lie in deep water or more solid structures are erected over the slope for supporting coal-tips. A dock (from Dutch 'dok' is a man-made feature involved in the handling of boats or ships Pilework jetties are also constructed in the water outside the entrances to docks on each side, so as to form an enlarging trumpet-shaped channel between the entrance, lock or tidal basin and the approach channel, in order to guide vessels in entering or leaving the docks. A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal Waterways. Solid jetties, moreover, lined with quay walls, are sometimes carried out into a wide dock, at right angles to the line of quays at the side, to enlarge the accommodation; and they also serve, when extended on a large scale from the coast of a tideless sea under shelter of an outlying breakwater, to form the basins in which vessels lie when discharging and taking in cargoes in such a port as Marseilles. Marseille, ( English alt Marseilles mɑrˈseɪ — French: maʁsɛj locally — Provençal Occitan: Marselha maʀˈsijɔ

At entrances to jetty harbors

Aerial view of Jetties at Humboldt Bay harbor entrance. The jetties mitigated bad habits of shifting sands and guarantee 700 feet in width at one of the most treacherous bar crossings in the world. ^[1]

The approach channel to some ports situated on sandy coasts is guided and protected across the beach by parallel jetties, made solid up to a little above low water of neap tides, on which open timber-work is erected, provided with a planked platform at the top raised above the highest tides. Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Characteristics A tide is a repeated cycle of sea level changes in the following stages Over several hours the water rises or advances up a beach in the flood The channel between the jetties was originally maintained by tidal scour from low-lying areas close to the coast, and subsequently by the current from sluicing basins; but it is now often considerably deepened by sand-pump dredging. Tidal scour is an Erosion process which is carried out by the Tidal movement of water A sluice is a water channel that is controlled at its head by a gate Dredging is an Excavation activity or operation usually carried out at least partly underwater in shallow seas or Fresh water areas with the purpose of It is protected to some extent by the solid portion of the jetties from the inroad of sand from the adjacent beach, and from the levelling action of the waves; whilst the upper open portion serves to indicate the channel, and to guide the vessels if necessary (see Harbor). A harbor or harbour (see spelling differences) or haven, is a place where ships may shelter from the Weather or are stored The bottom part of the older jetties, in such long-established jetty ports as Calais, Dunkirk and Ostend was composed of clay or rubble stone, covered on the top by fascine-work or pitching: but the deepening of the jetty channel by dredging, and the need which arose for its enlargement - led to the reconstruction of the jetties at these ports. Calais (kaˈlɛ in English often kæˈleɪ traditional English pronunciation /ˈkælɨs/ Kales is a town in northern France. Dunkirk ( French: Dunkerque, dœ̃kɛʀk or; Dutch:; is a harbour city and a commune in the northernmost part of France, in the ||-||-||} Ostend  (  Oostende, French and German Ostende) is a Belgian City and municipality located in the Flemish Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and The nes jetties at Dunkirk were founded in the sandy beach, by the aid of compressed air, at a depth of 22 3/4 ft. below low water of spring tides; and their solid masonry portion, on a concrete foundation was raised 50 ft. above low water of neap tides. Characteristics A tide is a repeated cycle of sea level changes in the following stages Over several hours the water rises or advances up a beach in the flood

At lagoon outlets

A small tidal rise spreading tidal water over a large expanse of lagoon or inland back-water causes the influx and efflux of the tide to maintain a deep channel through a narrows no longer confined by a bank on each side, becomes dispersed, and owing to the reduction of its scouring force, is no longer able at a moderate distance from the shore effectually to resist the action of tending to form a continuous beach in front of the outlet. Hence a bar is produced which diminishes the available depth in the approach channel. A shoal or sandbar (also called sandbank) is a somewhat Linear Landform within or extending into a body of Water, By carrying out a solid jetty over the bar, however on each side of the outlet, the tidal currents are concentrated in the channel across the bar, and lower it by scour. Thus the available depth of the approach channels to Venice through the Malaniocco and Lido outlets from the Venetian lagoon have been deepened several feet over their bars by jetties of rubble, carried out across the foreshore into deep water on both sides of the channel. Venice ( Italian: Venezia, Venetian: Venesia or Venexia) is a city in Northern Italy, the capital of the Other examples are provided by the long jetties extended into the sea in front of the entrance to Charleston harbour, formerly constructed of fascines, weighted with stone and logs, but subsequently of rubble stone, and by the two converging rubble jetties carried out from each shore of Dublin bay for deepening the approach to Dublin harbour. Charleston is a city in Charleston county in the US state of South Carolina. Dublin (ˈdʌblɨn/ /ˈdʊblɨn or /ˈdʊbəlɪn/, bˠalʲə aːha klʲiəh or cliə(ɸ is both the largest city and capital of Ireland.

Rivers

At the outlet of tideless rivers

Jetties have been constructed on each side of the outlet river of some of the rivers flowing into the Baltic, with the objects of prolonging the scour of the river and protecting the channel from being shoaled by the littoral drift along the shore. "Riverine" redirects here For the use of that term in Maritime geography, see there The Baltic Sea is a Brackish inland sea located in Northern Europe, from 53°N to 66°N Latitude and from 20°E to 26°E Longitude. Littoral refers to the coast of an ocean or sea or to the banks of a river lake or estuary The most interesting application of parallel jetties is in lowering the bar in front of one of the mouths of a deltaic river flowing into a tide - a virtual prolongation of its less sea, by extending the scour of the river out to the bar by banks. Jetties prolonging the Sulina branch of the Danube into the Black Sea, and the south pass of the Mississippi into the Gulf of Mexico, formed of rubble stone and concrete blocks, and respectively, have enabled the discharge of these rivers to scour away the bars obstructing the access to them; and they have also carried the sediment-bearing waters sufficiently far out to come under the influence of littoral currents, which, by conveying away some of the sediment, postpone the eventual formation of a fresh bar farther out (River engineering). The Danube (In Donau from earlier Danuvius, Celtic *dānu, meaning "to flow run" Slovak and Polish Dunaj The Black Sea is an inland Sea bounded by southeastern Europe, the Caucasus and the Anatolian peninsula ( Turkey Mississippi ( is a state located in the Deep South of the United States The Gulf of Mexico ( Spanish: Golfo de México) is the ninth largest Body of water in the world Littoral refers to the coast of an ocean or sea or to the banks of a river lake or estuary River engineering is the process of planned human intervention in the course characteristics or flow of a River with the intention of producing some defined benefit

At the mouth of tidal rivers

Where a river is narrow near its mouth, and its discharge is generally feeble, the sea is liable on an exposed coast, when the tidal range is small, to block up its outlet during severe storms. The river is thus forced to seek another exit at a weak spot of the beach, which along a low coast may be at some distance off; and this new outlet in its turn may be blocked up, so that the river from time to time shifts the position of its mouth. This inconvenient cycle of changes may be stopped by fixing the outlet of the river at a suitable site, by carrying a jetty on each side of this outlet across the beach, thereby concentrating its discharge in a definite channel and protecting the mouth from being blocked up by littoral drift. This system was long ago applied to the shifting outlet of the river Yare to the south of Yarmouth, and has also been successfully employed for fixing the wandering mouth of the Adur near Shoreham, and of the Adour flowing into the Bay of Biscay below Bayonne. The River Yare is a River in the English county of Norfolk. In its lower reaches the river connects with the navigable waterways of The Broads Great Yarmouth, often known to locals as Yarmouth, is a Coastal Town in Norfolk, England. Shoreham-by-Sea (shortened to Shoreham) is a small Town, Port and Seaside resort, also being the major settlement in the Adur District Cantabrian Sea redirects here Not to be confused with Biscay Bay Newfoundland and Labrador or Biscayne Bay. When a new channel was cut across the Hoek van Holland to provide a straighter and deeper outlet channel for the river Maas, forming the approach channel to Rotterdam, low, broad, parallel jetties, composed of fascine mattresses weighted with stone, were carried across the foreshore into the sea on either side of the new mouth of the river, to protect the jetty channel from littoral drift, and cause the discharge of the river to maintain it out to deep water. The Hook of Holland ( Dutch: Hoek van Holland - literally "Corner of Holland" also known in English as the Hook, is a town in Rotterdam (pronounced) is the 2nd-largest City by population in the Netherlands, located in the province of The channel, also, beyond the outlet of the river Nervion into the Bay of Biscay has been regulated by jetties; and by extending the south-west jetty out for nearly half a mile with a curve concave towards the channel the outlet has not only been protected to some extent from the easterly drift, but the bar in front has been lowered by the scour produced by the discharge of the river following the concave bend of the south-west jetty. Cantabrian Sea redirects here Not to be confused with Biscay Bay Newfoundland and Labrador or Biscayne Bay. As the outer portion of this jetty was exposed to westerly storms from the Bay of Biscay before the outer harbour was constructed, it has been given the form and strength of a breakwater situated in shallow water.

See also

• Jettied floors in medieval houses. Jettying is a building technique used in Medieval timber frame buildings in which an upper floor projects beyond the dimensions of the floor below
• Pier
• Port
• Wharf
• Groyne
• Mole

References

• This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. The Encyclopædia Britannica Eleventh Edition (1910–1911 is a 29-volume reference work that marked the beginning of the Encyclopædia Britannica The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
• Humboldt Bay Recreation & Conservation District: Humboldt Bay Harbor Setting