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Item Nearshore sediment exchange process around the cape comorin, the peninsular tip of india /(BioOne, 2024-12-20) Bragath, R. C.; Sivakholundu, K. M.Researchers have explored sediment transport's mechanism around the world's capes less than other coastal regions due to the multifaceted nearshore environment. Though recent research on nearshore sediment transport has advanced well, the complexity of sediment exchange around a Cape must be understood better. The coastal belt of Kanyakumari (Cape Comorin), India extends about 15 km on the east, bordering the Bay of Bengal, and about 55 km on the west, bordering the Arabian Sea with its confluence at the Indian Ocean. Unlike India's east and west coasts, the Kanyakumari coast follows a unique phenomenon in the coastal process, having peculiar wave climates resulting from the combined influences of ocean climate. The critical factor that causes changes in coastal configuration at the peninsular tip is the behavior of sediment transport. Most importantly, the exchange of sediments between the east and west coasts around this peninsular region is significant in determining the littoral drift pattern over the rest of the Indian coast. The present research work has studied the continuous movement of longshore currents over the peninsular tip using detailed active Littoral Environment Observation (LEO) for non-monsoon and monsoon seasons with varying wave climates and also relied on earlier studies taken up around the cape and assessed the significance of sediment transport around this littoral barrier. Field observations indicated that the littoral sediments reaching any potential barrier are likely to drift offshore and partly bypass to the adjacent cells within 20 m depth and partly deposited offshore during monsoon season. The sediments deposited offshore reach the beach again during fair weather, and such onshore movement builds up the stability of the eroded beach. During the ensuing monsoon period, these deposited sediments on the berm get eroded, carried into the sea, and deposited as offshore bars and maintain the beach's stability, providing enough sediment supply to the littoral cell system around the cape. The study highlights the significance of coastal dynamics and the interplay of nearshore sediment transport around the peninsular tip. We have also used mathematical modeling techniques to understand the hydrodynamic regime and the associated sediment exchange process.Item Managing a blackout : the consequences of an oil spill at sea /(Taylor & Francis, 2022-09-08) Shankar, Malini S.; Sivakholundu, K. M.The Ennore Oil Spill of 2017 triggered by a collision between two oil cargo vessels resulted in an environmental incident. This study is an attempt to cull the details from public domain and analyse the efficacy of the Government system to cope up with response. The information on events leading to the mishap indicates the suboptimal working conditions of seafarers prevailing on-board. The response activity drew negative publicity as the official communications were inconsistent. Besides declaring an under estimated quantum of oil spill, the perceived delay and inadequate resources seems to have aggravated the public sentiment. The episode of coastal spill clean-up came to close in two weeks with contributions from 30+ agencies of Government and industry along with 2000+ volunteers. The shoreline environment and fisheries activities returned to normalcy in three months’ time. Compensation to affected public was settled in a years’ time. However there is little information or unbiased evaluation of the episode available. An evaluation of such incidents will aid in addressing issues in future.Item A description of tidal propagation in Hooghly estuary using numerical and analytical solutions /(Elsevier, 2018-09-18) Sivakholundu, K. M.A tidal propagation characteristic of Hooghly estuary is presented using numerical (ADCIRC) and analytical models (Friedrichs and Aubrey, 1994) along with observations. The analytical model is based on Friedrichs and Aubrey (1994) that simplifies the governing hydrodynamic equations greatly by retaining only those terms that are significant without losing the overall understanding of the propagation process. The analytical model is compared with corresponding 2-D depth averaged numerical (ADCIRC) model that retains all non-linear terms. The assumptions for simplification are found to be reasonable in the light of close agreement among analytical, numerical models and observations. A plan-form geometrical characteristic as well as hydrodynamic variable of the Hooghly has been compared with that of Delaware estuary for corroborating similar tidal propagation process. The Hooghly estuary has flood dominant asymmetric tidal propagation and a positive amplitude growth factor (μ). The observed tidal celerity (phase speed) on an average is slightly more than frictionless celerity. Using the conventions of Toffolon et al. (2006), Hooghly can be classified into ‘strongly convergent – strongly dissipative’ estuary. From the results it can be construed that the estuary is yet to stabilise and reach its equilibrium morphology. It can be close to its equilibrium as very little amplification (0.1 m) is noticed in the predominant semi-diurnal constituent M2 over 78 km (barely 7%) in the estuary. The parameters of width variation (γ) and the ratio between friction and inertia (χ) have been used to define the marginal condition for amplification. The relative position of Hooghly in terms of marginal condition is consistent with similar set of estuaries elsewhere that have been grouped using the above parameters.Item Use of swath data in realtime navigation by pattern recognition(Marine Geodesy, 1989) Prabaharan, N.; Sivakholundu, K. M.A new method is proposed with the aim of reducing dead reckoning error (DRE) during multibeam echosounding survey in deep ocean. Bathymetric data is used in this method to estimate DRE in position fixing. This method can be activated at any desired interval to check the DRE accumulation in addition to available external navigation systems. A pattern recognition algorithm is developed to quantify the shift in position of a selected bathymetric feature that has been observed already once. This difference is used to correct the position fixing and navigation dataItem Stability analysis and design of offshore submerged breakwater constructed using sand filled geosynthetic tubes(Procedia Engineering, 2015) Kiran, A. S.; Ravichandran, V.; Sivakholundu, K. M.Kadalur Periyakuppam (KPK) is a fishing village located 70 km south of Chennai in Tamil Nadu. The coastline of KPK was subjected to severe erosion due to high energy waves during Thane (2011), Nilam (2012) and Madi (2013) cyclones. The Tamil Nadu Fisheries department facilities located near the coast is subjected to damage as the coastline has receded by 45 m in the last few years following the severe erosion caused by cyclones. Since most of the erosion occurred after the storm waves hit the shoreline, sustainable option for shoreline protection would be to shift wave breaking to deeper depths. Based on numerical model studies and assessment of shoreline behaviour over two years, it is proposed to construct a submerged segmented breakwater. The submerged breakwater is proposed to be constructed at 4 m water depth up to a height of 3.5 m using sand filled geosynthetic tubes. Geosynthetic tubes shall be placed in a stacked manner with 2 tubes of 1.5 m high each at the bottom and a tube of 2.5 m height at the top accounting for height loss due to settlement. Design and stability checks are carried out by using available literature as no standard methods or design codes are available for design or stability checks for the geosynthetic tubes. The breakwater structure is checked for stability against sliding, overturning and bearing capacity. The geosynthetic tube material specifications such as tensile strength, ultra violet ray resistance, apparent opening size and fabric material are calculated using suitable design methods. The scouring, in front and behind the breakwater structure under prevailing wave conditions, is estimated for designing scour protection.Item Evaluation of river regulatory measures in hughly estuary using tidal asymmetry characteristics(IEEE, 2006) Sivakholundu, K. M.; Kathiroli, S. ; Mani, J. S.; Idichandy, V. G.Tidal asymmetry has a profound effect on estuarine hydrodynamics and sedimentation pattern. The information of tidal asymmetry can be a useful tool to evaluate the flow pattern in shallow estuary and characterize the dominance of flood or ebb flow. The effects of features (like obstructions, depressions, etc.) and discharge variation in a theoretical channel section is simulated to quantify the parameters of tidal asymmetry. A set of proposed river regulatory measures in a shallow estuary (Hughly, India) was taken up for evaluation using tidal asymmetry parameters to check whether this may be used as additional tool. The indications provided (flood dominance and hence sediment importing regime) with asymmetry parameters do match with field conditions (based on bathymetry survey data). The asymmetry parameters may be put to use to evaluate the change in flood/ebb dominance in relative terms in a given section.Item Estuarine channel stability assessment through tidal asymmetry parameters(Journal of Coastal Research, 2009-03) Sivakholundu, K. M.; Mani, J. S.; Idichandy, V. G.; Kathiroli, S.In an estuarine channel the tidal asymmetry, sediment transport, and morphology are interconnected. To maintain a stable channel, we need to take tidal asymmetry into account. A relationship connecting tidal asymmetry and sediment transport rate has been used to evaluate the relative merits of channel modification through numerical simulations. Two criteria have been identified for ensuring the channel stability: (a) maintaining ebb dominance and (b) minimizing the spatial gradient in the net sediment transport function ⟨q⟩. Using these criteria for a test case, we have evaluated Hooghly estuary (east coast, India), where heavy sedimentation is experienced and a permanent solution is needed. The approach provides better insight into the sedimentation pattern in a semidiurnal tidal process in a shallow estuary with braided channels. Among the factors affecting tidal asymmetry, the relative phase difference (β) between M2 and M4 current constituents has a major influence and is thus responsible for the sedimentation pattern. Through numerical study it was found that a combination of deepened, uniform channel with enhanced ebb flow led to a favorable β, indicating less deposition.Item Design of sustainable shore protection solution using geosynthetic tubes(GA 2016 - 6th Asian Regional Conference on Geosynthetics, 2016) Kiran, A.; Ravichandran, V.; Jebakumar, P.; Abhishek, T.; Sivakholundu, K. M.Item Application of parametric acoustics for shallow-water near-surface geophysical investigations(IEEE, 2006-05) Vasudevan, Manoj; Sivakholundu, K. M.; Venkata Rao, D.; Kathiroli, S.Shallow-water near-surface geophysical investigations were carried out, under two different scenarios - one to assess the status of a pipeline in the West coast and the other to assess the effect of water-injection dredging in the East coast of India. In both these investigations, Parametric Sediment Echo Sounder (SES-2000), a system developed by Innomar Technologie GmbH, which makes use of the parametric acoustical effect, was used. In the former case, profiles were taken across a pipeline at regular intervals to determine whether it was buried or exposed. The parametric system produces a 2D geo-acoustic section in which the pipe is indicated by a hyperbolic curve. The exposed height or buried depth of the pipeline at a crossing is then estimated. This investigation could, also, reveal the geomorphologic changes in the immediate vicinity of the pipeline. In the latter case, parametric acoustics was utilized to provide supplementary results for the assessment of water-injection dredging. Parametric acoustic data could expose the abrupt termination of certain near-seabed layer interfaces and sediment accumulations along steep slope, quite convincingly. SES-2000 proved to be handy to investigate the near-surface sub-seabed, especially in areas where conventional or popular methods find practical difficulties to be carried out.Item A program to compute the area of an irregular polygon on a spheroidal surface(Computers and Geosciences, 1998) Sivakholundu, K. M.; Prabaharan, N.