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Groyne

About: Groyne is a research topic. Over the lifetime, 397 publications have been published within this topic receiving 4549 citations. The topic is also known as: groin & Breakwater.


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Journal ArticleDOI
TL;DR: In this article, the effects of navigation on young-of-the-year (YOY) fish were investigated for the Danube River based on an integrative approach, and the characteristics of vessel-induced waves were correlated to YOY-drift.
Abstract: The effects of navigation on young-of-the-year (YOY) fish were investigated for the Danube River based on an integrative approach. During YOY growing season, wave height, wave frequency and water currents were recorded. Synchronously, fish drift and fish abundance of YOY were monitored in two distinct inshore nursery habitats—a gravel bar and a groyne field. The characteristics of vessel-induced waves were correlated to YOY-drift. In both habitats, an increase in drift densities during ship passages was observed. At the same time, assemblage composition and drift densities differed between habitat types. At the gravel bar, drift densities of larval cyprinids—representing many keystone species of the Danube—were higher during ship passages. In the groyne field, drift was low and percids dominated the YOY-assemblage along the shore. Banks with gentle slopes in the main channel seem to be particularly affected by vessel-induced wave wash. Precisely such habitats are often established within the scope of modern river restoration projects because they provide suitable nursery habitats for riverine fish species. Beside the positive effects on biota, the establishment of these habitats in navigable reaches may create problems for YOY-fish due to displacement effects induced by ship-generated waves.

27 citations

Journal ArticleDOI
TL;DR: In this article, the authors present the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary.
Abstract: Overuse of groundwater in coastal areas, due to high population and agricultural activity results in seawater intrusion into the coastal aquifer. This paper presents the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary. Due to overexploitation of groundwater and less rainfall in past years, adjacent seawater has started intruding in the Kalangi river sub-surface and deteriorating groundwater quality up to 11.6 km from the confluence of the river with Pulicat lake. To prevent this situtation, subsurface dams were constructed in traditional manner using local earth material in three different places across the Kalangi river near Sullurpet town. The water storage capacities calculated after the sub-surface dams’ construction are 1.28 mcft at GK Engineering College, 6.23 mcft at Challamagudi and 3.143 mcft at Holy Cross School sites. The Holy Cross School sub-surface dam is the first full scale dam-cum-check dam constructed to prevent salt water intrusion in the Kalangi river at Sullurpet, Nellore district, Andhra Pradesh. At the Kalangi river estuary portion (at the mouth of sea) a groyne was reconstructed over old groyne site with the introduction of clay bed and wooden sheet piles at down stream. Apart from prevention of sea water entry into Kalangi river sub-surface (during seasons) the groyne top level was raised to prevent mixing of high sea water tides with fresh water and ensuring additional storage of fresh water at upstream side. The reconstructed groyne was serving the purpose of obstructing the surface seawater entry in the Kalangi river and water quality has improved in the river as well as in the wells. After construction of sub-surface dam, as per the Simpson ratio classification, there is substantial improvement of water quality in the SHAR infiltration well situated near the Holy Cross School sub-surface dam.

26 citations

Journal ArticleDOI
TL;DR: In this article, the effect of large-scale roughness on banks, 36 geometries of axi-symmetric, rectangular cavities were investigated in a laboratory flume under subcritical, turbulent free surface flow conditions.
Abstract: Transverse or longitudinal movements of a water body are observed for flows along cavities, river embayments, groyne fields or harbours. They are significant for certain flow conditions and geometrical properties. To study the effect of large-scale roughness on banks, 36 geometries of axi-symmetric, rectangular cavities were investigated in a laboratory flume under subcritical, turbulent free surface flow conditions. Significant movements of the water body were detected. The frequency of these periodic movements, identified by level and velocity observations, is in agreement with the natural frequency of the water body in a rectangular basin assuming the first-order mode of sloshing. Major movements of the water body, which lead to significant and periodic oscillations of the water surface, are avoided by excluding Strouhal numbers near 0.42 and 0.84. For low aspect cavity ratios, the periodic water-surface oscillations are insignificant if the flow reattaches to the sidewalls of the widened channel reach.

26 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of artificial dead zones, such as groyne fields, on the transport of a spill in a river has been analyzed, and it is shown that in the case of low water discharges with a suppressed flow in the Lower-Rhine River, measured concentration distributions of a few accidental spills were considered.

26 citations

Journal ArticleDOI
TL;DR: In this article, the influence factors of groyne are complexly related to the stream characteristics, hydrologic variables, hydraulic characteristics, and local variables, the analysis considered the influences of all factors is difficult.
Abstract: Groynes usually are installed along the river side and those are used for various purposes including flow and erosion control and bank protection. Recently, the concern of groynes that provide us with ecological environment and improvement of scenary near river has greatly increased for naturalized river and ecological river restoration. However there is no adequate design guideline in Korea. Furthermore there is little research for the installation of groynes in Korea. Especially, since the influence factors of groyne are complexly related to the stream characteristics, hydrologic variables, hydraulic characteristics, and local variables, the analysis considered the influences of all factors is difficult. For that reason, most of existing researches have been focused about local scour at the tip of groynes with sandy bed condition and flow pattern near groynes and recirculation zone. In this study, to evaluate influence factor of the interval of groynes, experiments of flow pattern near groynes and recirculation zone with the variation of permeability, approaching velocity, groyne length, and installed angle have been performed. We also measured the tip velocity of groynes and that is scour factor near groyne. Empirical equations for recirculation zone and tip velocity of gryones were determined.

26 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202114
202020
201924
201823
201714
201617