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Item The coastal zone of Mangalore is acquiring an ever-increasing importance due to its rich ocean resources and favourable conditions for development of port based industries. All weather New Mangalore Port (NMP) Trust is the administrative unit of the port, which caters to the needs of large, medium and small-scale industries. The NMP is situated 10 km North of Mangalore, along Karnataka Coast, West Coast of India. The present study was carried out with a view to (i) understand sediment dynamics (ii) erosion/accretion pattern and (iii) study the coastal processes in the vicinity of the NMP breakwaters. Beach face sediment samples were collected and statistical parameters were determined using Folk and Ward (1957) formulae and then Sediment Trend Matrix (STM) was prepared. The STM was used to draw Sediment Transport Paths (STP), from which predominant sediment transport direction was identified. The performance of breakwaters at NMP was assessed by lead line soundings data. Based on the present study it is concluded that the net sediment transport in the vicinity of the NMP coast is very small. There are no significant changes observed in the bathymetry and shoreline in the vicinity of NMP due to breakwaters construction.(Prediction of shoreline evolution by statistical analysis of beach samples and surveys at new Mangalore Port) Dwarakish, G.S.; Natesan, U.2005Item 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 Global water quality indices for river Gurpur, Karnataka State, India(2010) Rajagopal, B.; Shrihari, S.; Dwarakish, G.S.Three water quality indices viz. Drinking Water Quality Index (DWQI), Health Water Quality Index (HWQI) and Acceptability Water Quality Index (AWQI) were developed by United Nations Environment Programme (UNEP) under the Global Environment Monitoring System (GEMS)/Water for global comparison of quality of water sources. In this paper these three global water quality indices were determined for River Gurpur, in Karnataka state of India. Gurpur is one of the important west flowing rivers of India and is the source for industrial needs of fast developing Mangalore city. River water samples were collected from Gurpur River at Gurpur Bridge on National Highway -13 near Mangalore monthly from November 2006 to October 2007. The samples were analyzed for sixteen physico-chemical and bacteriological parameters. The global water quality indices determined for river Gurpur can be designated as 'Fair' during the study period. The seasonal variation in global water quality indices ranged from 'Marginal' to 'Excellent'. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Geomorphological behaviour of Sasihithlu, Mangalore coast, west coast of India(2011) Nagaraj, G.; Karjagi, A.; Kumar, M.; Dwarakish, G.S.Beach geomorphological studies have been carried out with help of conventional methods and remote sensing techniques. Conventional methods include beach profile surveys and beachwidth measurements whereas remote sensing techniques involved in utilization of satellite images, digitization and analyses. Beach profile surveys and beachwidth measurements are carried out at monthly intervals over a period of one year (September 2009 to September 2010) to understand dynamics of sediment along the coastal segment of 7km at Sasihithlu, north off Mangalore coastline. Six locations are selected based on their significant site characteristics along the coastal segment. It is observed erosion with steeper slopes during the monsoon and simultaneously deposition with flat and wider exposed slopes during the fair weather season. But the more drastic and dramatic changes are observed in the vicinity of Mulki-Pavanje rivermouth, since the rivers Mulky and Pavanje bring any kind of sediments irrespective of seasons. Because of this the profiles alter dramatically in the vicinity of rivermouth. It is estimated that the Sasihithlu beach has experienced a net loss of about 2515m 3/m, a net gain of about 3525m 3/m and hence a gain of about 1010m 3/m sediments in an annual cycle. Addition to conventional methods, remote sensing analysis is also carried out to detect the influence of rivers and their flow on rivermouth system in recent decades (1988-2009) with the help of satellite images and GIS tools. It is observed that the shifting tendency of rivermouth either south or north irrespective of seasons. However a detailed investigation on shoreline pattern showed a clear indication of shifting shoreline towards south. Therefore present study suggests to construct coastal protection structures on either side of the rivermouth, through that the damage to the property could be minimized. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Seawalls: Performance and their failure analysis along Southern Karnataka, West Coast of India(2012) Rao, S.; Hegde, A.V.; Dwarakish, G.S.; Janardhan, J.; Venkat Reddy, D.Beach erosion is a major problem along the south west coast of India. The beach erosion particularly along the south Karnataka coast is due to, 1) direct attack of waves in an open coast, which might have been intensified in some areas due to wave refraction, 2) erosion at river mouths where one or two rivers together join the sea. The coastal protection works adopted along the South Karnataka coast are mainly the seawalls. However, some portions of these seawalls have been damaged either partially or fully. A critical study shows that these failures are due to the scouring at the toe structure. Scouring causes the failure of the seawall due to loss of support. A calculated risk may be taken to design the seawall without taking scour depth into account but provide for adequate maintenance in case scour occurs and partial failure of the seawall takes place. © 2012 Cafet-Innova Technical Society. All rights reserved.Item Land use/land cover changes around Rameshwaram Island, east coast of India(National Institute of Science Communication and Policy Research, 2014) Gowthaman, R.; Dwarakish, G.S.; Sanilkumar, V.Land-use/land cover changes are studied using the Indian Remote Sensing satellite (IRS-1C, IRS-P6) Linear Image Self-scan Sensor (LISS) III data of 1998 and 2010. Coastal land use categories such as sand, vegetation, coral reef and water have been identified using interpretation keys. Results of land-use/land cover assessment based on visual interpretation are presented. The study indicates water body of 178 and 177 km2, sand features of 32 and 32 km2, vegetation of 28 and 35 km2 and coral reef of 5 and 6 km2 respectively. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.Item Improving multiple model ensemble predictions of daily precipitation and temperature through machine learning techniques(Nature Research, 2022) Jose, D.M.; Vincent, A.M.; Dwarakish, G.S.Multi-Model Ensembles (MMEs) are used for improving the performance of GCM simulations. This study evaluates the performance of MMEs of precipitation, maximum temperature and minimum temperature over a tropical river basin in India developed by various techniques like arithmetic mean, Multiple Linear Regression (MLR), Support Vector Machine (SVM), Extra Tree Regressor (ETR), Random Forest (RF) and long short-term memory (LSTM). The 21 General Circulation Models (GCMs) from National Aeronautics Space Administration (NASA) Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) dataset and 13 GCMs of Coupled Model Inter-comparison Project, Phase 6 (CMIP6) are used for this purpose. The results of the study reveal that the application of a LSTM model for ensembling performs significantly better than models in the case of precipitation with a coefficient of determination (R2) value of 0.9. In case of temperature, all the machine learning (ML) methods showed equally good performance, with RF and LSTM performing consistently well in all the cases of temperature with R2 value ranging from 0.82 to 0.93. Hence, based on this study RF and LSTM methods are recommended for creation of MMEs in the basin. In general, all ML approaches performed better than mean ensemble approach. © 2022, The Author(s).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 INFLUENCE OF LAND USE LAND COVER CHANGE ON RUNOFF CHARACTERISTICS OF NETRAVATHI RIVER CATCHMENT, KARNATAKA, INDIA(Zibeline International Publishing Sdn. Bhd., 2024) Dwarakish, G.S.; Pai, J.B.; Jubina, C.K.The effect of LU/LC on the streamflow characteristics of the Netravathi river basin, Karnataka, India, is studied using Soil and Water Assessment Tool (SWAT) model. Landsat images, soil map from FAO, ASTER DEM (30m grid) and streamflow data, forms the database for the present work. The most significant changes from 1981 to 2015, in the LU/LC includes agricultural land (31.86%), built-up area (67.9%), forest cover (-20.01%), coconut plantation (55.12%), other vegetation (-18.55%) and others (-11.82%). The verification of performance of model was carried out by the coefficient of determination values (R2 > 0.8) and N S E (NSE > 0.78) were obtained and hence proved that SWAT model performance in estimating streamflow.. The average streamflow is increased by 13.74% from 1981 to 2015, which is mainly due to dynamic changes in LU/LC. Hence, it can be concluded that changes in LU/LC have a direct impact on streamflow in the study area. © 2024, Zibeline International Publishing Sdn. Bhd.. All rights reserved.Item Unravelling flood complexity: statistical and neural network approaches for Cauvery River Basin, India(Springer Science and Business Media B.V., 2024) Sahu, M.K.; Shwetha, H.R.; Dwarakish, G.S.Floods are widespread natural calamities with substantial socio-economic effects that demand adequate management measures and forecasts. In this study, the most popular traditional statistical distribution techniques, Gumbel, Log Pearson-III (LP-III), Log-Normal (LN) and three soft computing techniques such as Artificial Neural Networks (ANN), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Adaptive Neuro-Fuzzy Inference System-Firefly Algorithm (ANFIS-FFA) were examined for their potential to predict floods. These approaches were employed for modelling yearly maximum discharge at M.H. Halli, T. Narasipur, Kollegal, Biligundulu, Urachikottai, Kodumudi, and Musiri gauging stations of the Cauvery River using 40 years (1980 to 2019) data. Two statistical constraints, the wilton index (WI) and the root mean square error (RMSE), are employed to determine the performance of the proposed hybrid model. The results showed that, for M.H. Halli, Biligundulu, Urachikottai, Kodumudi, and Musiri gauging stations, ANFIS-FFA gave the highest WI values as 0.9141, 0.9636, 0.9205, 0.9373, and 0.8939, whereas and for T. Narasipur, and Kollegal gauging stations the ANN gave the highest WI value 0.8524 and 0.9440, respectively, during the testing phase. Futhermore, the coefficient of determination (R2) for ANFIS-FFA at M.H. Halli, Biligundulu, Urachikottai, Kodumudi, and Musiri gauging stations were 0.9140, 0.9636, 0.9205, 0.9378, and 0.8999, respectively and for ANN at T. Narasipur, Kollegal gauging stations were of R2 as 0.8574 and 0.9440, respectively. Based on these results, it can be concluded that the soft computing techniques (ANFIS-FFA and ANN) outperformed the statistical techniques. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.