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J.k. Tripathy - One of the best experts on this subject based on the ideXlab platform.
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Littoral Drift by alongshore flow at visakhapatnam east coast of india
Journal of Hydro-environment Research, 2010Co-Authors: J.k. Panigrahi, Sathish V Kumar, J.k. TripathyAbstract:Abstract The Littoral Drift in the surf zone of Visakhapatnam has been evaluated using simulated longshore current. In this study we examined Littoral processes, driven by longshore currents using a set of numerical models (Mike-21 modeling system). Deepwater waves as they approach shallow water dissipate energy and the water from the broken waves flow parallel to the shoreline known as longshore current. In order to simulate the current from wave breaking, offshore wave data for the period 1995–2004, have been collected from British Meteorological Office (BMO), UK. Waves having an annual exceedance of 20% are allowed to propagate to nearshore using a nearshore spectral wind-wave model from predominant directions. The wave-induced radiation stress obtained from wave model then formed the basis for simulating the longshore current and associated sediment transport. The results of these simulations show the pattern of longshore flow and sedimentation. The net annual discharge at selected coastal stretches is estimated and presented. It has been inferred from the study that the sediment transport for the coast is of the order of 0.4–0.6 million m3/year.
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Littoral Drift by alongshore flow at Visakhapatnam – East Coast of India
Journal of Hydro-environment Research, 2010Co-Authors: J.k. Panigrahi, V. Sathish Kumar, J.k. TripathyAbstract:Abstract The Littoral Drift in the surf zone of Visakhapatnam has been evaluated using simulated longshore current. In this study we examined Littoral processes, driven by longshore currents using a set of numerical models (Mike-21 modeling system). Deepwater waves as they approach shallow water dissipate energy and the water from the broken waves flow parallel to the shoreline known as longshore current. In order to simulate the current from wave breaking, offshore wave data for the period 1995–2004, have been collected from British Meteorological Office (BMO), UK. Waves having an annual exceedance of 20% are allowed to propagate to nearshore using a nearshore spectral wind-wave model from predominant directions. The wave-induced radiation stress obtained from wave model then formed the basis for simulating the longshore current and associated sediment transport. The results of these simulations show the pattern of longshore flow and sedimentation. The net annual discharge at selected coastal stretches is estimated and presented. It has been inferred from the study that the sediment transport for the coast is of the order of 0.4–0.6 million m3/year.
J.k. Panigrahi - One of the best experts on this subject based on the ideXlab platform.
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Littoral Drift by alongshore flow at visakhapatnam east coast of india
Journal of Hydro-environment Research, 2010Co-Authors: J.k. Panigrahi, Sathish V Kumar, J.k. TripathyAbstract:Abstract The Littoral Drift in the surf zone of Visakhapatnam has been evaluated using simulated longshore current. In this study we examined Littoral processes, driven by longshore currents using a set of numerical models (Mike-21 modeling system). Deepwater waves as they approach shallow water dissipate energy and the water from the broken waves flow parallel to the shoreline known as longshore current. In order to simulate the current from wave breaking, offshore wave data for the period 1995–2004, have been collected from British Meteorological Office (BMO), UK. Waves having an annual exceedance of 20% are allowed to propagate to nearshore using a nearshore spectral wind-wave model from predominant directions. The wave-induced radiation stress obtained from wave model then formed the basis for simulating the longshore current and associated sediment transport. The results of these simulations show the pattern of longshore flow and sedimentation. The net annual discharge at selected coastal stretches is estimated and presented. It has been inferred from the study that the sediment transport for the coast is of the order of 0.4–0.6 million m3/year.
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Littoral Drift by alongshore flow at Visakhapatnam – East Coast of India
Journal of Hydro-environment Research, 2010Co-Authors: J.k. Panigrahi, V. Sathish Kumar, J.k. TripathyAbstract:Abstract The Littoral Drift in the surf zone of Visakhapatnam has been evaluated using simulated longshore current. In this study we examined Littoral processes, driven by longshore currents using a set of numerical models (Mike-21 modeling system). Deepwater waves as they approach shallow water dissipate energy and the water from the broken waves flow parallel to the shoreline known as longshore current. In order to simulate the current from wave breaking, offshore wave data for the period 1995–2004, have been collected from British Meteorological Office (BMO), UK. Waves having an annual exceedance of 20% are allowed to propagate to nearshore using a nearshore spectral wind-wave model from predominant directions. The wave-induced radiation stress obtained from wave model then formed the basis for simulating the longshore current and associated sediment transport. The results of these simulations show the pattern of longshore flow and sedimentation. The net annual discharge at selected coastal stretches is estimated and presented. It has been inferred from the study that the sediment transport for the coast is of the order of 0.4–0.6 million m3/year.
Charitha Pattiaratchi - One of the best experts on this subject based on the ideXlab platform.
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The influence of coastal reefs on spatial variability in seasonal sand fluxes
Marine Geology, 2013Co-Authors: Shari L. Gallop, Cyprien Bosserelle, Ian Eliot, Charitha PattiaratchiAbstract:The effect of coastal reefs on seasonal erosion and accretion was investigated on 2 km of sandy coast. The focus was on how reef topography drives alongshore variation in the mode and magnitude of seasonal beach erosion and accretion; and the effect of intra- and inter-annual variability in metocean conditions on seasonal sediment fluxes. This involved using monthly and 6-monthly surveys of the beach and coastal zone, and comparison with a range of metocean conditions including mean sea level, storm surges, wind, and wave power. Alongshore ‘zones’ were revealed with alternating modes of sediment transport in spring and summer compared to autumn and winter. Zone boundaries were determined by rock headlands and reefs interrupting Littoral Drift; the seasonal build up of sand over the reef in the south zone; and current jets generated by wave set-up over reefs. In spring and summer, constant sand resuspension and northerly Littoral Drift due to sea breezes allowed a sand ramp to form in the South Zone so that sand overtopped the reef to infill the lagoon. This blocked the main pathway for sand supply to downDrift zones which subsequently eroded. In autumn and winter, with the dominance of northwesterly storms and reversal in the direction of Littoral Drift, the South Zone eroded and sand travelled through the lagoon in the current jet to nourish the northern beaches. Inter-annual and seasonal variation in sea level, storm frequency and intensity, together with pulsational effects of local sand fluxes at Yanchep due to inter-seasonal switching in the direction of Littoral Drift determined marked differences in the volumes of seasonal sand transport. These seasonal ‘sediment zones’ highlighted interesting and unexplored parallels between coasts fronted seaward by coral reefs and rock formations.
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LONGSHORE SEDIMENT TRANSPORT DUE TO SEA BREEZES: AN IMPOUNDMENT STUDY
Coastal Engineering 2002, 2003Co-Authors: Aafke Tonk, Gerhard Masselink, Charitha PattiaratchiAbstract:The coastline of Perth, Western Australia, is subject to one of the strongest and most consistent sea breeze systems in the world. A significant feature of the sea breeze is that it blows obliquely-onshore and has a major impact on the incident wave climate and ensuing longshore sediment transport. Reviews of field data on longshore sediment transport have concluded that there are large uncertainties regarding the behaviour on low-wave energy, steep beaches. This study investigates the applicability of conventional equations to predict Littoral Drift rates on a site characterised by steep beach morphology, low-wave energy conditions and a bi-modal wave climate. Littoral Drift rates were measured during an impoundment study, which involved monitoring the longshore transport rate by blocking sand movement with a permanent shorenormal groyne. Weekly surveys were conducted during a five-month period and these successive surveys provide data on changes in beach morphology and volume. The results are compared with three different predictions based on wave data and Littoral Drift equations (CERC and Inman and Bagnold (1963) equations). The longshore sediment transport is predicted well using the CERC equation when only considering the contribution of the wind waves. The sea breeze generated Littoral Drift is estimated 40,000–60,000 m. This investigation confirms that the sea breeze system plays and important role in determining the sediment budget in the region. INTRODUCTION The beaches along the coastline of Perth, Western Australia, are characterised by a steep gradient (5–6 ) and are subjected to low-wave energy conditions. The coastline is 1 Graduate Student, Geography Department, Loughborough University, Loughborough, LE11 3TU, UK. A.M.Tonk@lboro.ac.uk 2 Senior Lecturer, Geography Department, Loughborough University, Loughborough, LE11 3TU, UK. G.Masselink@lboro.ac.uk 3 Associate Professor, Centre for Water Research, University of Western Australia, Nedlands, WA 6907, Australia. Pattiara@cwr.uwa.edu.au
Satoshi Tohma - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium Flow Area of Tidal Inlets Affected by Littoral Drift
Coastal Engineering 2000, 2001Co-Authors: Zhaowu Meng, Hideo Kondo, Satoshi TohmaAbstract:Change on flow area of tidal inlets affected by low Littoral Drift, and the critical velocities at tidal inlets are studied by reinvestigation of the stable cross-sectional]low area theory (Kondo, 1990). Variation trends of flow area are shown based on the analyses of tidal inlets on the coast of Northern Island, New Zealand. Sedimentation trend in the inlet channel, scouring trend around construction at tidal inlets and navigation maintenance are shown through studies on Brown Cedar Cut in the USA, Notoro Fishery Port in Japan and Sanya Harbor in China.
José Carlos Nunes - One of the best experts on this subject based on the ideXlab platform.
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Sandy sediment budget of the midcoast of Rio Grande do Sul, Brazil
Journal of Marine Research, 2015Co-Authors: Lucas Marchi Da Motta, Elírio Ernestino Toldo, Brito De Almeida, José Carlos NunesAbstract:Calculation of the coastal sediment budget involves estimation of the timing and intensity of processes of erosion, transport, and deposition, as well as an understanding of local and regional sediment dynamics. The modern sedimentary deposits present in the coastal zone constitute the physical basis of coastal ecosystems. Knowledge of the dynamics of these sediments from the source to sink area, through regional sediment management, is critical to understanding the long-term stability of the coastal zone and the fate of these important natural resources. In this article, the Littoral cell concept has been applied to the midcoast of Rio Grande do Sul, a wave-dominated and dissipative-intermediate sandy coast in southern Brazil. To analyze Littoral Drift variations along the 275 km long study area, the shoreline was divided into 12 cells. Littoral Drift rates were estimated and compared using the energy flux method. Wave parameters were obtained from WAVEWATCH III. The sand volume of the coastal dune field (4.20 billion m3) was quantified using satellite imagery and the aeolian transport rates estimated utilizing the sediment budget residual. The net annual longshore transport rates obtained with the Coastal Engineering Research Center equation range from 0.60 to 2.63 million m3 per year. The Littoral Drift rates obtained with the Van Rijn (2001) and Kamphuis (1991) equations range between 0.15 and 1.00 million m3 per year. Based on the sediment budget and dune field age, the CERC formula seems more appropriate to estimate longshore transport.