Faculty Publications
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Item Simulation of varada aquifer system for sustainable groundwater development(2008) Ramesh, H.; Mahesha, A.Groundwater flow modeling has been used extensively worldwide with varying degrees of success. The ability to predict the groundwater flow is critical in planning and implementing groundwater development projects under increasing demand for fresh water resources. This paper presents the simulation of the aquifer system for planning the groundwater development of Varada basin, Karnataka, India using the Galerkin finite-element method. The government of Karnataka State, India is implementing the World Bank assisted project, "Jal Nirmal" for a sustainable development of the region, thereby ensuring a safe supply of drinking water to the northern districts of the state. Varada basin is one of the beneficiaries of the project in Haveri district. Field tests carried out in the study area indicate that the region is predominantly a confined aquifer with transmissivity and storage coefficients ranging from 5.787×10-6m2/s (0.500 m2/day) to 4.213×10-3m2/s (3.640×102m2/day) and 0.011-0.001× 10-2, respectively. This study mainly emphasizes the spatial and temporal variability of groundwater potential under different developmental scenarios. The model predictions were reasonably good with correlation coefficients ranging from 0.78 to 0.91 with the root mean square error of about 0.46-0.78 during calibration and validation. The stated accuracies are based on comparisons between measured and calculated heads. The outcome of the study would be a useful input for the conjunctive use of surface water and groundwater planning for the sustainable development of the region. © 2008 ASCE.Item Identification of Artificial recharge sites in hard rock terrain using RS and GIS in Chintapally Mandal, Nalgonda District, Andhra Pradesh, India(2010) Raju, A.; Reddy, A.G.S.; Venkat Reddy, D.A study has been undertaken to identify the favorable areas for artificial recharge in Chintapally mandal in Nalgonda district, Andhra Pradesh. Geographical Information System (GIS) and Remote Sensing technology contributes an efficient and effective result oriented methods for studying the occurrence and movement of groundwater resources. Integration of various thematic layers such as geomorphology, slope, soil types, lineament density, and drainage density have been used to identify the suitable zones for the artificial recharge in the study area. For identifying the suitable zones, weightage and ranking scores were assigned to each thematic layer then using ARC/INFO GIS software, the above themes have been integrated and the areas suitable for artificial recharge have been identified using spatial analysis tools from GIS environment. The favorable areas for artificial recharge have been categorized into Very Good, Good, Moderate to Good, Moderate, Poor to Moderate and poor for recharge in the study area. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Characterizing aquifers when using magnetic resonance sounding in a heterogeneous geomagnetic field(EAGE Publishing BV P.O.Box 18667 Newark NJ 07191-8667, 2011) Vouillamoz, J.M.; Legchenko, A.; Nandagiri, L.It has previously been reported that the heterogeneity of the geomagnetic field disturbs the currently-measured free induction decay signal of magnetic resonance sounding (MRS). To overcome the limitation of MRS in a non-homogeneous geomagnetic field, we adapted the spin-echo methodology usually used at the laboratory scale and in boreholes. We present examples of measurements carried out in a sandy aquifer in southern India. The 15-25 m thick sand deposit overlays a gneissic basement. Two sources of geomagnetic field heterogeneity have been identified at this site, both affecting the geomagnetic field within the sandy aquifer: the gneissic bedrock and an intruded dyke into the bedrock. Spin-echo and free induction decay signals have been recorded at six locations. We found that the groundwater content, the thickness of the saturated aquifer and its transmissivity calculated with free induction decay measurements are underestimated compared to those derived from spin-echo measurements. The closer to the dyke the higher the underestimation. Time-domain electromagnetic measurements indicate that the aquifer is rather homogeneous at the site scale, as suggested by spin-echo results. We also found that a small heterogeneity of the geomagnetic field can go unnoticed, thus leading to an unknown mis-estimate of aquifer properties when using free induction decay measurements. Thus spin-echo measurements can be used to improve the accuracy of aquifer characterization when using MRS in geological contexts where geomagnetic field heterogeneity exists. © 2010 European Association of Geoscientists & Engineers.Item Tropical, Seasonal River Basin Development through a Series of Vented Dams(2011) Shetkar, R.V.; Mahesha, A.Tropical rivers are predominantly seasonal in nature, and managing water resources during the deficit period is becoming more difficult because of the rapidly increasing demand for water. The present investigation focuses on harvesting Netravathi River water in the southern Indian peninsula through a series of vented dams with an estimated storage capacity of 102 Mm3 for use during the deficit period. A brief hydraulic design of a vented dam at a specific location is presented. The spacing and capacity of these reservoirs were worked out on the basis of the dam height and the river characteristics. The proposed vented dams are seasonal dams, and the closure of the vents will be decided on the flow available (i.e., 95% dependable flow), the storage capacity, and the minimum water release required for the downstream ecosystem. The appropriate time to start storing water in the vented dams was estimated to be in the month of November, and the entire process of storing water in the vented dams may last for about 41 days. An operational protocol for the storing process is presented. The investigations of aquifer parameters were performed by using electrical resistivity, pumping, and soil tests. The results indicated that the aquifer is shallow, unconfined in nature, and had a depth ranging from 18 to 30 m and hydraulic conductivity ranging from 62.6 to 406 m/day. A multiple regression model developed to assess the groundwater recharge in the adjoining well fields indicated that water table fluctuations may be 30% of reservoir level fluctuations. Because the river is also tidal in nature, a saltwater exclusion dam is proposed at the lower reaches of the river to prevent the entry of saltwater along the river during the summer period. © 2011 American Society of Civil Engineers.Item Fuzzy logic modeling for groundwater level forecasting of west coast region in India(2011) Dandagala, D.; Deka, P.C.Forecasting the groundwater table in unconfined aquifer is essential for efficient planning of conjunctive use in a basin. In this study, fuzzy logic (FL) models have been developed for groundwater level forecasting in west coast humid region of Karnataka state, India. The FL modeling was carried out to forecast the groundwater table by one week lead time at three different sites over the study area. Mamdani fuzzy inference system was adopted in the present study and finally centroid of area defuzzification method has been applied to obtain crisp output. The results concluded that the FL model performed quite satisfactorily as assessed by various performance indices such as Root mean square error, Coefficient of correlation, and Mean absolute error. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Identification and Apportionment of Pollution Sources to Groundwater Quality(Springer Basel info@birkhauser-science.com, 2016) Gulgundi, M.S.; Shetty, A.Characterizing groundwater quality and apportionment of pollution sources to groundwater pollution is important for managing water resources effectively. Owing to rapid industrialization and population growth in Bengaluru city, the groundwater quality is getting deteriorated. Receptor modeling by Multi-Linear Regression of the Absolute Principal Component Scores (APCS-MLR) has been used to evaluate the source apportionment of groundwater pollution in order to recognize and quantify the pollution sources. Groundwater quality data measured for pre-monsoon and post-monsoon in the year 2014, comprising 14 physico-chemical parameters from 68 sites distributed across the study area, have been used. Principal component analysis identified four factors explaining 79.2 % of the total variance. Receptor modeling using APCS-MLR provided apportionment of different sources responsible for the groundwater quality along with percentage contribution of the recognized sources to each parameter. Results revealed that most of the variables were primarily affected by rock water interactions, seepage of sewage and industrial effluent. It was also found that few parameters gained significant contribution from the unidentified sources. Finally, the model performance was evaluated based on the ratio of estimated mean to measured mean (E/M). It was found that except for Fe with (E/M) ratio as high as 7.1, the model showed moderate strength with (E/M) values ranging from 0.51 to 2.83 of all the other parameters. © 2016, Springer International Publishing Switzerland.Item Low cost Fenton's oxidative degradation of 4-nitroaniline using iron from laterite(IWA Publishing 12 Caxton Street London SW1H 0QS, 2016) Amritha, A.S.; Manu, B.The present study aims to establish the use of iron (Fe) from larerite in the case of Fenton's oxidation process which is a simple and cost-effective method for degradation of nitro compounds in effluents and in surface or ground water. 4-nitroaniline (4-NA) degradation by Fenton's oxidation method is the subject of the present study so as to optimize pH, hydrogen peroxide/iron (H/F) ratio at different initial concentrations of 4-NA. The optimum pH obtained was 3. The present study has also established optimum H/F ratio for the different initial concentrations of 4-NA for both conventional and use of Fe from laterite. The maximum removal efficiency of 99.84% was obtained for an H/F ratio of 100 for 0.5 mM initial concentration of 4-NA. The study establishes the use of Fe extracted from locally available laterite soil (LS) as a replacement of Fe salts so as to reduce the cost of the process. © 2016 IWA Publishing.Item Groundwater quality assessment of urban Bengaluru using multivariate statistical techniques(Springer Verlag, 2018) Gulgundi, M.S.; Shetty, A.Groundwater quality deterioration due to anthropogenic activities has become a subject of prime concern. The objective of the study was to assess the spatial and temporal variations in groundwater quality and to identify the sources in the western half of the Bengaluru city using multivariate statistical techniques. Water quality index rating was calculated for pre and post monsoon seasons to quantify overall water quality for human consumption. The post-monsoon samples show signs of poor quality in drinking purpose compared to pre-monsoon. Cluster analysis (CA), principal component analysis (PCA) and discriminant analysis (DA) were applied to the groundwater quality data measured on 14 parameters from 67 sites distributed across the city. Hierarchical cluster analysis (CA) grouped the 67 sampling stations into two groups, cluster 1 having high pollution and cluster 2 having lesser pollution. Discriminant analysis (DA) was applied to delineate the most meaningful parameters accounting for temporal and spatial variations in groundwater quality of the study area. Temporal DA identified pH as the most important parameter, which discriminates between water quality in the pre-monsoon and post-monsoon seasons and accounts for 72% seasonal assignation of cases. Spatial DA identified Mg, Cl and NO3 as the three most important parameters discriminating between two clusters and accounting for 89% spatial assignation of cases. Principal component analysis was applied to the dataset obtained from the two clusters, which evolved three factors in each cluster, explaining 85.4 and 84% of the total variance, respectively. Varifactors obtained from principal component analysis showed that groundwater quality variation is mainly explained by dissolution of minerals from rock water interactions in the aquifer, effect of anthropogenic activities and ion exchange processes in water. © 2018, The Author(s).Item Geo-statistical analysis of groundwater quality in an unconfined aquifer of Nethravathi and Gurpur river confluence, India(Springer Science and Business Media Deutschland GmbH, 2018) Sylus, K.J.; Ramesh, H.The groundwater quality plays a vital role in domestic, industrial and agricultural water supply. However, seawater intrusion was one of the major problems occur worldwide in the coastal aquifers due to excessive pumping of fresh groundwater. Thus, groundwater gets contaminated due to seawater intrusion, disposal of industrial waste etc. Due to this reason, it becomes necessary for regular monitoring of groundwater quality, in order to take proper measures for avoiding and reducing contamination. Hence, the present study was aimed to assess water quality in Nethravathi and Gurpur river confluence, located on the west coast of India. Groundwater samples were collected for the month of January 2013–May 2017, which was further analysed in the laboratory as per Bureau of Indian Standards (BIS) and World Health Organisation (WHO) standards. The water quality parameters considered for analysis are Potential Hydrogen (pH), Sodium (Na), Potassium (K), Electrical conductivity (EC), Chloride (Cl), Total Dissolved Solids (TDS), Calcium (Ca), Magnesium (Mg), Total Hardness (TH) and Bicarbonate (HCO3). The results of these parameters were further mapped using Geographical Information System (GIS) to visualize spatial distribution. The geo-statistical analysis was also carried out using SPSS tool to know the correlation of these parameters. The regression analysis was carried out with Factor of sea to the chemical parameters such as Bicarbonate (HCO3), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Calcium (Ca), Magnesium (Mg) and Total Hardness (TH). The significant groundwater quality chemical parameters were found by correlation analysis. The significant groundwater quality chemical parameters were further given as input for mapping, prediction and modelling of groundwater quality. The prediction of significant parameters carried out using the monthly groundwater quality data for the year 2013 and 2014. The result of spatial mapping and statistical analysis provides the spatial and temporal variation of groundwater quality in the study area. The results showed that only Panganimuguru and Kunjatbail region is affected by seawater. The modelling results of Cl and TDS shows 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 519 m towards the freshwater zone of the study area. © 2018, Springer International Publishing AG, part of Springer Nature.Item GIS-based multi-criteria analysis for identification of potential groundwater recharge zones - a case study from Ponnaniyaru watershed, Tamil Nadu, India(KeAi Communications Co., 2020) Devanantham, D.; Subbarayan, S.; Singh, L.; Jennifer, J.J.; Saranya, T.; Kulithalai Shiyam Sundar, K.S.S.Groundwater is one of the most vital natural resources; spatially varying in quality and quantity. Increased urbanisation and population creates tremendous pressure on the quality and quantity of the groundwater resources. In this study, Ponnaniyaru watershed of Cauvery basin was considered for this research. Geographical information system (GIS) and remote sensing (RS) plays a vital role in preparing various thematic layers for targeting the groundwater potential zones (GWPZ). This study adopts the Analytical Hierarchy Process (AHP) and Multi influence factor (MIF), multi-criteria decision-making approaches to determine the weights for the influencing factors. Weighted linear overlay analysis was carried out to determine the GWPZ. Further, the resultant GWPZ map has been reclassified into five different classes, namely Very good, Good, Moderate, Poor and Very poor. The results were validated with observed well-yield data, and the predictive precision for AHP and MIF was found to be 75%, and 71% respectively. © 2020 The Authors