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A groyne (groin in the United States) is a rigid hydraulic structure built out from the shore (in coastal engineering) or from the bank (in rivers) and interrupts the flow of water and sediment. Groynes serve a multitude of functions.
In coastal engineering Groynes are one of the most common and effective methods of coastal defense against transportation of sediment. Groynes are structures which run perpendicular to the shoreline. Groynes extend from the upper foreshore or beach down towards the sea, usually at right angles to the sea. Groynes are usually made of wood, concrete, or piles of large rocks. Groynes are generally constructed in groups called groyne fields. Image File history File links No higher resolution available. ...
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Coastal defenses are objects and engineering techniques used to defend coasts against erosion and flooding. ...
The foreshore, also called the intertidal or littoral zone, is that part of a beach that lies between average high tide and average low tide. ...
For other uses, see Beach (disambiguation). ...
This article is about the body of water. ...
The length, elevation, and spacing between groynes should be determined according to local wave energy and beach slope. Groynes that are too long or too high tend to accelerate downdrift erosion because they trap too much sand. Groynes that are too short, too low, or too permeable are ineffective because they trap too little sand. Flanking may occur if a groyne does not extend far enough landward. In the earth sciences, permeability (commonly symbolized as κ, or k) is a measure of the ability of a material (typically, a rock or unconsolidated material) to transmit fluids. ...
Flank is a word which might mean any of several different things: A flank is the side of either a horse or a military unit. ...
Groynes are extremely cost-effective, requiring little maintenance, and are one of the most common coastal defence structures. However, groynes are increasingly viewed as making the coastline look unnatural and ugly, and are opposed by many people. Groynes are very often used in tandem with seawalls to provide a very effective means of coastal defence. A seawall is a form of hard coastal defence constructed on the inland part of a coast to reduce the effects of strong waves and are built in the water. ...
How groynes work The purpose of a groyne is to create and maintain a healthy beach on its updrift side, which in turn provides protection to the land behind. These effects are achieved through two main processes. First, groynes act as a barrier to physically stop sediment transport (sand) in the direction of longshore transport through the system. This causes a build-up of the beach on the groyne's updrift side. Secondly, groynes interrupt the tidal flow forcing the tidal current further offshore beyond the groyne end. This slows the tidal current inshore causing the deposition of heavier sediments and encouraging the beach to grow in size. This article or section cites very few or no references or sources. ...
For other uses, see Sand (disambiguation). ...
In geography, longshore drift (LSD) refers to a process by which sediments move along a beach shoreline. ...
This article is about tides in the ocean. ...
However, this is often accompanied by accelerated erosion of the downdrift beach, known as terminal groyne syndrome, as it occurs after the terminal groyne, which receives little or no sand via longshore transport. (It is important to realize that groynes do not add any new sand to the beach, but merely retain some of the existing sand on the updrift side of the groin.) If a groyne is correctly designed, then the amount of material it can hold will be limited, and excess sediment will be free to move on through the system. However, if a groyne is too large it may trap all the sediment reaching it and this can cause severe beach erosion problems on the down-drift side, which in turn can result in coastal deposition problems. For morphological image processing operations, see Erosion (morphology). ...
In rivers Groynes (often referred to as "spur dikes" or "wing dykes"), are often constructed (nearly) perpendicular to the river banks, beginning at the riverbank with a root and ending at the regulation line with a head. They serve to maintain a desired channel for the purpose of preventing ice jamming, improved navigation and erosion control over lateral erosion, that would form Meanders. Groynes have a major impact on the river morphology; generally speaking, they cause autonomous degradation of the river. The areas between the groynes are referred to as groyne fields. [1] For other uses, see River (disambiguation). ...
This article is about determination of position and direction on or above the surface of the earth. ...
Terraces, conservation tillage, and conservation buffers save soil and improve water quality on this Iowa farm. ...
A meander is a bend in a river, also known as an oxbow loop, or simply an oxbow. ...
River morphology is the field of science dealing with changes of river planform and cross-section shape due to sedimentation and erosion processes. ...
Types of groynes Various types of groynes can be distinguished according to their construction, action on stream flow and appearance. Przedwojski et al. (1995)[2], claim that the following is necessary for a full description of groynes:
Classification according to the method and materials of construction Groynes may be permeable, allowing the water to flow through at reduced velocities, or impermeable, blocking and deflecting the current. Permeable groynes are fabricated from piles, bamboo or timbers, whereas impermeable groynes (also called solid groynes or rock armour groynes) are constructed using rock, gravel, gabions, etc.
Classification according to submergence stage Groynes may be designed either as submerged or as non-submerged under normal conditions. Which of the two types will be used is dictated by the design conditions. Usually impermeable groynes are designed to be non-submerged, since flow over the top of solid groynes may cause severe erosion along the shanks. Submerged groynes, on the other hand, may be designed permeable, depending on the degree of flow disturbance that is needed.
Classification according to the action on the stream flow Groynes may be classified as attracting, deflecting or repelling. Attracting groynes point downstream, they serve to attract the stream flow toward themselves and do not repel the flow toward the opposite bank. Deflecting groynes are generally short ones and used for local protection. They serve to change the direction of flow without repelling it. Repelling groynes point upstream. They serve to force the flow away from themselves.
Classification according to their appearance in planview Groynes may be built with different planview shapes. Examples are straight groynes, T head, L head, hockey stick, inverted hockey stick groynes, straight groynes with pier head, wing, or tail groynes.
Gallery Groynes in the Waal river, part of the Rhine in the Netherlands Image File history File links No higher resolution available. ...
WAAL (The Whale) is a classic rock radio station broadcasting at 99. ...
For other uses, see Rhine (disambiguation). ...
Motto: Je Maintiendrai (Dutch: Ik zal handhaven, English: I Shall Uphold) Anthem: Wilhelmus van Nassouwe Capital Amsterdam1 Largest city Amsterdam Official language(s) Dutch2 Government Parliamentary democracy Constitutional monarchy - Queen Beatrix - Prime minister Jan Peter Balkenende Independence Eighty Years War - Declared July 26, 1581 - Recognised January 30, 1648 (by Spain...
| Groyne on the East coast of England Photograph of groynes in the UK. Photo taken by Tarquin File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
For other uses, see England (disambiguation). ...
| Groyne at Crescent Beach in Surrey, British Columbia, Canada Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2272 × 1704 pixel, file size: 1. ...
Location of Surrey Country Province Regional District Metro Vancouver Incorporation 1879 (municipality status) 1993 (city status) Government - Mayor Dianne Watts - Governing body - MLAs List of MLAs Harry Bains (NDP) Jagrup Brar (NDP) Bruce Ralston (NDP) Kevin Falcon (LIB) Dave Hayer (LIB) Gordon Hogg (LIB) Sue Hammell (NDP) leader_title3 = MPs Area...
| Timber groynes in Bournemouth, England Image File history File links Size of this preview: 800 × 505 pixelsFull resolution (1010 × 637 pixel, file size: 79 KB, MIME type: image/jpeg) Isle of Wight Centre for the Coastal Environment I, the copyright holder of this work, hereby release it into the public domain. ...
, Bournemouth ( ) is a large town and tourist resort, situated on the south coast of England. ...
| Timber groyne in Bournemouth, England Image File history File links Size of this preview: 800 × 528 pixelsFull resolution (1000 × 660 pixel, file size: 93 KB, MIME type: image/jpeg) Isle of Wight Centre for the Coastal Environment I, the copyright holder of this work, hereby release it into the public domain. ...
| Groyne in Holland Image File history File links Metadata Size of this preview: 799 × 599 pixelsFull resolution (1025 × 769 pixel, file size: 209 KB, MIME type: image/jpeg) Jordi Serra I, the copyright holder of this work, hereby release it into the public domain. ...
| Groyne on the Isle of Wight Image File history File links Metadata Size of this preview: 799 × 599 pixelsFull resolution (1025 × 769 pixel, file size: 215 KB, MIME type: image/jpeg) Jordi Serra I, the copyright holder of this work, hereby release it into the public domain. ...
For other uses, see Isle of Wight (disambiguation). ...
| Groynes in Sitges Image File history File links No higher resolution available. ...
Sitges (Latin: Blanca Subur) (pronunciation: [] in IPA) is a small city about 40 kilometers south west of Barcelona renowned worldwide for its Film Festival and Carnival. ...
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Sluice gates near Henley, on the River Thames A small wooden sluice in Magome, Japan, used to power a waterwheel. ...
The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset. ...
Canal locks in England. ...
For other uses, see River (disambiguation). ...
Butchers Creek, Omeo, Victoria A stream, brook, beck, burn or creek, is a body of water with a detectable current, confined within a bed and banks. ...
For other uses, see Canal (disambiguation). ...
Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...
Water resources are sources of water that are useful to human beings for drinking, recreation, irrigation, livestock production, industry, etc. ...
Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ...
References - ^ Yossef, Mohamed F.M. (November 2005). Morphodynamics of Rivers with Groynes. DUP Science. ISBN 90-407-2607-8.
- ^ PRZEDWOJSKI, B.; BLAZEJEWSKI R., PILARCZYK K. W. (1995). River training techniques- fundamentals, design and application. A.A. Balkema.
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