Faculty Publications
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Item Coastal vulnerability assessment of the future sea level rise in Udupi coastal zone of Karnataka state, west coast of India(2009) Dwarakish, G.S.; Vinay, S.A.; Natesan, U.; Asano, T.; Kakinuma, T.; Venkataramana, K.; Pai, B.J.; Babita, M.K.Udupi coast in Karnataka state, along the west coast of India, selected as a study area, is well known for sandy beaches, aquaculture ponds, lush greenery, temples and major and minor industries. It lies between 13°00?00?-13°45?00? north latitudes and 74°47?30?-74°30?00? east longitudes, the length of the coastline is 95 km, and is oriented along the NNW-SSE direction. It is vulnerable to accelerated sea level rise (SLR) due to its low topography and its high ecological and touristy value. The present study has been carried out with a view to calculate the coastal vulnerability index (CVI) to know the high and low vulnerable areas and area of inundation due to future SLR, and land loss due to coastal erosion. Both conventional and remotely sensed data were used and analysed through the modelling technique and by using ERDAS Imagine and geographical information system software. The rate of erosion was 0.6018 km2/yr during 2000-2006 and around 46 km of the total 95 km stretch is under critical erosion. Out of the 95 km stretch coastline, 59% is at very high risk, 7% high, 4% moderate and 30% in the low vulnerable category, due to SLR. Results of the inundation analysis indicate that 42.19 km2 and 372.08 km2 of the land area will be submerged by flooding at 1 m and 10 m inundation levels. The most severely affected sectors are expected to be the residential and recreational areas, agricultural land, and the natural ecosystem. As this coast is planned for future coastal developmental activities, measures such as building regulation, urban growth planning, development of an integrated coastal zone management, strict enforcement of the Coastal Regulation Zone (CRZ) Act 1991, monitoring of impacts and further research in this regard are recommended for the study area. © 2009 Elsevier Ltd. All rights reserved.Item Development of prediction models for hydrodynamic performance of semicircular breakwater(2012) Aggarwal, A.; Gope, V.K.; Managiri, S.S.; Hegde, A.V.Breakwaters are structures built to protect harbors, shore areas, basins, and other areas from the fury of sea waves. They create calm waters and provide for the safe mooring and handling of ships, as well as protection to harbor facilities. The main function of a breakwater is the formation of an artificial harbor. Of late, certain new types of breakwaters have been constructed to cater to the tranquility requirements of managing marine traffic in ports. The semicircular breakwater (SBW) is one such new type of breakwater. The semicircular breakwater possesses a round top and, thus, offers more stability against the action of waves. It is expected that the SBW will be well suited as an offshore breakwater designed to protect beaches from coastal erosion. A number of experiments were conducted on scaled-down physical models of SBW for different values of parameters such as wave height H, wave period T, spacing of perforations on the seaside, etc. (radius of breakwater and diameter of perforations were kept constant), and data were collected. The paper presents the prediction models/equations for hydrodynamic performance characteristics such as reflection coefficient and relative wave runup, using the data obtained by a regression approach in MATLAB.Item Time-series analysis of erosion issues on a human-intervened coast– A case study of the south-west coast of India(Elsevier Ltd, 2023) Parvathy, M.M.; Balu, R.; Dwarakish, G.S.Coastal erosion has long been identified as a cause of concern for the state of Kerala, situated in the Indian subcontinent, affecting the life and livelihood of millions residing in the coastal belt. The increased human interference supplemented by changes in the climatic pattern in recent years has modified the coastal scenario of the state altogether. The present study attempts to evaluate the effect of anthropogenic influences in modifying the coastal scenario to review the efficiency of the coastal management policy adopted by the state over the years. For this purpose, the shorelines extracted from the available multi-temporal satellite images are analysed using DSAS software to calculate the shoreline change rate prior to 2000 (1973-98) and post-2000 (2002-21) using the linear rate of regression method. The study seeks to key out critically eroding areas, subsequently exploring the possible conducive reasons for the changed coastal scenario. The results indicate a reduction of 34.5% in the share of eroding length, with a visible shift in a substantial portion of coastal stretch from the mild erosion category to the stable category. Despite the state's continuous efforts to curb the issue, the long-term shoreline change over the past 49 years (1973–2021) reveals erosion to be dominant in nearly 39.12% of the coastal length, with the share of eroding length in the southern, central and northern regions as 33.8%, 38.67% and 44.04%, respectively. The results point towards the dominance of human interventions accompanied by climate change impacts as the primary reason for transforming the coast, necessitating the need to modify the state's current coastal management policy. The research emphasises the need for a comprehensive coastal management plan for the state to take heed of the changing climatic scenario. © 2023 Elsevier LtdItem Development of a regional-scale erosion vulnerability assessment approach along a human-intervened coast–a case study from the southern part of Kerala, India(Taylor and Francis Ltd., 2025) Parvathy, M.M.; Balu, R.; Dwarakish, G.S.The coastal district of Thiruvananthapuram, situated in the southern part of the state of Kerala, is endowed with sandy beaches, majestic cliffs, scenic backwaters and rocky promontories, aside from hosting a sizeable coastal population, well-known tourist attractions, unique biodiversity, and numerous developmental activities. However, erosion is one hazard that gravely impacts these zones, disturbing the coastal environment and affecting the lives of thousands residing in these regions. The present study attempts to identify the critical vulnerable areas to erosion, considering the combined influence of hazard parameters, i.e. drivers of erosion and risk parameters, i.e. the assets at stake. A multi-criteria decision-making approach, integrated with expert ranking, is adopted in the present study to identify and classify the vulnerable stretches, demanding urgent intervention to prevent further erosion and safeguard vital resources. The results indicate that approximately 10% of the coast falls under low vulnerability, 77% under medium vulnerability, 12 % under high vulnerability, and 1% under very high vulnerability. The coastal reaches of Shangumugham and Anchuthengu are identified as highly vulnerable and in urgent need of intervention. The spatial distribution of vulnerability necessitates a focused and site-specific management plan to tackle the present and possible erosion issues and protect critical resources. © 2025 Indian Society for Hydraulics.Item Hydrodynamic performance of floating kelp farms: Wave attenuation and coastal protection potential(Elsevier Ltd, 2025) Surakshitha; Rao, M.; Rao, S.Ecologically rich coastal zone play a crucial role in supporting both biodiversity and the economy. “Soft solutions” for coastal protection, such as vegetated breakwaters and artificial reefs, harness natural features to mitigate coastal erosion. Among these, flexible floating vegetation, such as kelp farms, presents a unique mechanism by altering flow patterns differently than bed-fixed vegetation. This study experimentally investigates the effectiveness of floating kelp farms in dissipating wave energy under monochromatic regular waves. The wave heights ranging from 0.06 m to 0.18 m and periods of 1.6 s–2.8 s is considered. The study examines the effects of two non-dimensional parameters: relative farm width (w/L, 0.1 to 2.5) and relative blade length (l/d, 0.25–1.0), representing the ratios of farm width to wavelength and blade length to water depth, respectively. Under the test conditions investigated, the highest wave dissipation coefficient (Kd ? 0.8) is observed for relative blade lengths of 0.75 and 0.5 at a water depth of 0.45 m. The optimal farm configuration occurred at a relative farm width between 0.3 and 0.4. These findings contribute to a better understanding of the role of kelp farm in wave energy dissipation and highlight its potential as a sustainable alternative for coastal protection. © 2025 Elsevier LtdItem Coastal vulnerability assessment of the Kasaragod Coast in Kerala, West Coast of India(Springer Nature, 2025) N A, A.; Makhdumi, W.; G S, D.; Pai, J.Coastal zones are transition zones between the land and sea, characterised by unique coastal ecosystems and natural resources, making them the focal point of human activities. Vulnerability assessments have been carried out along several coastal zones across the world. These assessments help coastal scientists, engineers, and policymakers prepare plans and devise mitigation measures to safeguard the environment and coastal population against climate change and coastal hazard impacts. The present study evaluates the vulnerability of the Kasaragod coast in Kerala, the west coast of India, due to sea-level rise. Eleven variables, viz. relative sea-level change, mean significant wave height, tidal range, geomorphology, shoreline change rate, regional elevation, coastal slope, population, road/railway networks, tourist sites and land use/land cover are considered in the estimation of the Coastal Vulnerability Index (CVI). The resulting CVI values were categorized into low, moderate, high and very high vulnerability classes. Based on this classification, 41.33% of the Kasaragod sub-district and 13.26% of the Hosdurg sub-district fall under the ‘very high’ vulnerability category. A significant decrease in vulnerability was observed along the Kasaragod sub-district when socioeconomic variables were excluded from the CVI calculation. However, in the Hosdurg sub-district exclusion of the socioeconomic variables led to increased vulnerability along the coast. The vulnerability maps developed in this study provide a crucial tool for identifying highly vulnerable coastal stretches and guiding effective strategies to safeguard the Kasaragod coast and its communities. © The Author(s) 2025.