Conference Papers
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Item Groundwater modeling to simulate groundwater levels due to interlinking of rivers in Varada river basin, India(2011) Ramesh, H.; Mahesha, A.Using a two-dimensional Gelarkin finite element model, the present study characterizes groundwater flow in a Varada basin, a semi humid area of Karnataka, India. The model characterization involved taking field data by conducting pump tests describing an aquifer system. Geological geometry and the number of aquifers have been analyzed based on a large amount of geological, hydrogeological and topographical data. The aquifer properties are then transformed into input variables that the model code uses to solve governing equations of flow. The results of the field experiments showed that Varada basin is predominantly confined aquifer. For calibrating the numerical groundwater model, the groundwater flow was simulated in steady state. Results of study demonstrate a moderately high correlation between the observed and simulated groundwater level. In addition, the groundwater level and trend in the transient state has also been elucidated. The validated numerical groundwater model was used to predict the groundwater levels due to impact of recharge from the interlinking of rivers in the basin. The model result provides an excellent visual representation of groundwater levels, presenting resource managers and decision makers with a clear understanding of the nature of the interaction of groundwater levels with the proposed interlinking project. Results build a base for further analysis under different future scenarios for implementation. © 2011 IEEE.Item A numerical modeling approach for study of mudbank impact on coastline(Institute of Electrical and Electronics Engineers Inc., 2015) Parvathy, K.G.; Ramesh, H.; Noujas, V.; Thomas, K.V.Coastal zone is the triple interface of land, ocean and atmosphere. Any developmental activity along the coastal zone requires a clear understanding of the dynamic processes controlling its very existence. When most of the processes, which are common to all coastlines are quite well known, there are some localized, but important processes requiring further research for developmental planning. Mudbanks are such an inquisitive coastal phenomenon which occurs only at a few locations in the nearshore waters of the world ocean. Mudbanks, its occurrence, nature, properties and characteristics are interesting subjects from engineering point of view. The objective of the study is to provide an insight of mudbank impact on coastal morphology through a numerical modeling approach. For a better understanding of the influence of mudbanks on coastal morphology, Munambam to Chettuwa sector of Thrissur coast which is a part of Southwest coast of India is considered. In the present study the description of coastline evolution due to impact of mudbank is calculated using LITLINE module of LITPACK software package. It is observed that the occurrence, non-occurrence and migration of mudbanks influence the coastal dynamics significantly along mudbank influenced coastal stretch of Kerala. © 2014 IEEE.Item Effectiveness of contrast limited adaptive histogram equalization technique on multispectral satellite imagery(Association for Computing Machinery acmhelp@acm.org, 2017) Ganesh, V.R.; Ramesh, H.Contrast Limited Adaptive Histogram Equalization technique (CLAHE) is a widely used form of contrast enhancement, used predominantly in enhancing medical imagery like X-rays and to enhance features in ordinary photographs. This paper aimed to understand the effectiveness of using this technique in multispectral satellite imagery and to study its effectiveness in different regions of the electromagnetic spectrum. This study also aimed at analyzing variations of spatial and spectral resolutions of a sensor affect the performance of the CLAHE technique by means of comparing quantitative parameters of the enhanced images between the sensors. A general idea of the feature that can be enhanced in each spectral region was also studied. The results showed that a comparative study between the CLAHE technique and the conventional global histogram equalization technique resulted in the former technique emerging superior of the two and thereby reconstructed images of better quality. © 2017 Association for Computing Machinery.Item Modeling of the transport of leachate contaminant in a landfill site: A case study in mangaluru(CRC Press/Balkema, 2018) Divya, A.; Shrihari, S.; Ramesh, H.Ground water flow and the solute transport model MODFLOW and MT3DMS were established to determine the spread of contamination from a landfill maintained by Mangaluru City Corporation at Vamanjoor, located nearly 8.5 km from the center of the city. As Vamanjoor is home for many educational institutes and also a residential area, the spread of the contamination has to be analyzed. For this study, the aquifer considered is a subbasin of the Gurupur basin. This study has focused on handling the data available in the most efficient way to develop a consistent simulation model. The model was calibrated successfully with RMSE value of observed versus simulated head as 0.32 m. The evaluation of model was also done by comparing with the measured water head and chloride level from the field on a seasonal basis. After validating successfully, the model was run to determine the extent of contamination and also to forecast a scenario for maximum rainfall. The results show that the contamination has spread to a distance of 1 km from the landfill and with maximum rainfall the spread will be around 1.8 km from the landfill. © 2018 Taylor & Francis Group, London.Item Modelling of groundwater quality using bicarbonate chemical parameter in Netravathi and Gurpur river confluence, India(American Institute of Physics Inc. subs@aip.org, 2018) Sylus, K.J.; Ramesh, H.In the coastal aquifer, seawater intrusion considered the major problem which contaminates freshwater and reduces its quality for domestic use. In order to find seawater intrusion, the groundwater quality analysis for the different chemical parameter was considered as the basic method to find out contamination. This analysis was carried out as per Bureau of Indian standards (2012) and World Health Organisations (1996). In this study, Bicarbonate parameter was considered for groundwater quality analysis which ranges the permissible limit in between 200-600 mg/l. The groundwater system was modelled using Groundwater modelling software (GMS) in which the FEMWATER package used for flow and transport. The FEMWATER package works in the principle of finite element method. The base input data of model include elevation, Groundwater head, First bottom and second bottom of the study area. The modelling results show the spatial occurrence of contamination in the study area of Netravathi and Gurpur river confluence at the various time period. Further, the results of the modelling also show that the contamination occurs up to a distance of 519m towards the freshwater zone of the study area. © 2018 Author(s).Item Impact of land use land cover change on run off generation in tungabhadra river basin(Copernicus GmbH info@copernicus.org, 2018) Venkatesh, K.; Ramesh, H.Streamflow can be affected by a number of aspects related to land use and can vary promptly as those factors change. Urbanization, deforestation, mining, agricultural practices and economic growth are some of the factors related to these land use changes which alter the stream flow. In the present study, the impact of land use land cover change (LULC) on stream flow is studied by using SWAT model for Tungabhadra river basin, located in the state of Karnataka, India. Tungabhadra river originates in the Western Ghats of Karnataka and flows towards north-east and joins the river Krishna. The land use maps of 1993, 2003 and 2018 are used for assessing the stream flow changes with respect to LULC. Calibration and validation of the model for streamflow was carried out using the SUFI-2 algorithm in SWAT-CUP for the years 1983-1993 and 1994-2000 respectively. Statistical parameters namely Coefficient of Determination (R2) & Nash-Sutcliffe (N-S) were used to assess the efficiency and performance of the SWAT model. It was found that the observed and simulated streamflow values are closely matching, which in turn projects that the model results are acceptable. The calibrated model was used for simulation of future dynamic land use scenario to assess the impact on streamflow. The results can be used for conservation of water and soil management. © 2018 Authors.Item Comparison of Different Pan Sharpening Techniques using Landsat 8 Imagery(Institute of Electrical and Electronics Engineers Inc., 2019) Govind, N.R.; Rishikeshan, C.A.; Ramesh, H.Pan sharpening technique is a widely used image processing technique which combines the data available from various sensors and exploits its varied capabilities. In this study, the efficiency of four diverse pan sharpening methods namely High Pass filter, Modified Intensity Hue Saturation, Ehlers fusion and Hyperspectral Colour Sharpening was evaluated. The pan sharpening approaches are applied to Landsat 8 imagery of an urban area. The spatial and spectral quality of the fused images is assessed using different indices like Bias, RMSE, Correlation Coefficient and ERGAS. The fused images obtained have improved spatial resolution and visual appearance compared to the original MS image. The fused images have a spatial resolution comparable to that of the PAN image. According to visual analysis, Modified IHS method yielded a fused image with better visual interpretability. The statistical analysis shows that the high pass filter is the most suitable pan sharpening method for this dataset. On testing for Bias, RMSE, ERGAS and CC, the high pass filter method performed best followed by Modified Intensity Hue saturation, Ehlers fusion and Hyperspectral Colour Sharpening while Ehlers fusion showed a higher correlation, compared to Modified IHS. © 2019 IEEE.Item Water level retrieval and water body mapping: A case study of nagarjuna sagar reservoir(Springer Science and Business Media Deutschland GmbH, 2021) Nalluri, N.; Ramesh, H.Satellite radar altimetry is exclusively designed for the oceanographic studies such as wind speed, sea surface level, tide height, and volumetric changes. In spite of the fact that the satellite radar altimetry is predominantly intended for oceanographic studies and ice sheet monitoring these days, the utilization of altimetry information is reached out to think about water dimension of inland water bodies like reservoirs, rivers and so on. This study covers the use of SENTINEL-3 Ku/C Radar Altimeter (SRAL) for the monitoring water level of Nagarjuna Sagar reservoir located in Telangana state, India. Satellite altimetry works on the principle of range measurement that is the measure of the travel time of microwave pulse from emission to receiving which is interrupted by many atmospheric conditions which cause a disturbance in travel time of microwave pulse which is to be adjusted to get corrected depth of water level. The SRAL information is handled utilizing Broadview Radar Altimetry Toolbox (BRAT) programming. The consistency of derived water level is compared using field data, and all the depths are within error range of one meter. Water body mapping is carried out utilizing cloud-free data of Landsat-8 from January 2016 to March 2019 which showed a gradual decrease in water level from November to May. © Springer Nature Singapore Pte Ltd 2021.Item Satellite Image Fusion using FDCT for Land Cover Classification(Institute of Electrical and Electronics Engineers Inc., 2021) Naik, S.K.; Ramesh, H.Remote sensing is a fast developing field of science involving repetitive collection of data from earth observing satellites. However each satellite system has one or more limitations, giving rise to the need of data collection from multiple sources and their fusion. Landsat 8 collects images in a broad spectrum but at a coarser spatial resolution of 30m. Cartosat-1 collects images at a high spatial resolution of 2.5m but lacks color details. Good visually interpretable images are indispensable for land cover classification. In this paper, the Landsat 8 and Cartosat-1 images are fused by using the Fast Discrete Curvelet Transform (FDCT) method. Supervised classification using the Random Forest (RF) classifier is performed on the Landsat 8 multispectral image and the fused image. The results showed high quality of image fusion based on the entropy, RMSE and CC values obtained for the given dataset. The fusion process also improved the overall accuracy of the land cover classification. © 2021 IEEE.Item Groundwater Quality Evaluation In The Gurupura River Basin Using GIS and Remote Sensing Approach(Institute of Electrical and Electronics Engineers Inc., 2023) Suryawanshi, V.; Ramesh, H.; Nasar, T.The objective of this study was to assess the quality of groundwater resources in the Gurupura basin, located in Dakshina Kannada district, Karnataka, India, specifically for domestic and drinking purposes. To achieve this, various water quality analysis techniques were employed, such as the water quality index (Brown's 1970), spatial groundwater evaluation using GIS-based interpolation, and multivariate statistical analysis. Physiochemical parameters of groundwater samples were analyzed on-site both before and after the monsoon season of 2021. The findings of the study indicate that the groundwater quality deteriorates during the pre-monsoon period, primarily due to a decline in the groundwater table and the presence of salinity in coastal wells. However, in the post-monsoon period, the groundwater quality significantly improves and is deemed pure and suitable for both drinking and domestic purposes. © 2023 IEEE.