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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 Parameter estimation and vulnerability assessment of coastal unconfined aquifer to saltwater intrusion(2012) Mahesha, A.; Vyshali; Lathashri, U.A.; Ramesh, H.The focus of the present work is to characterize a tropical, coastal aquifer and to carry out its vulnerability to saltwater intrusion using hydrogeological parameters. The characterization of the aquifer involves pumping tests, vertical electrical sounding, and water quality analysis carried out at 41 monitoring wells. The area under investigation lies between two tropical, seasonal, tidal rivers, i.e., Pavanje and Gurpur rivers, joining the Arabian on the west coast of India. The aquifer is predominantly shallow and unconfined, having moderate to good groundwater potential with transimissivity and specific yield ranging from 49.2 to 461:4 m2/day and 0.00058 to 0.2805, respectively. The electrical resistivity tests indicated that the thickness of the aquifer ranges from 18 to 30 m. The study also investigates the saltwater affected areas in the region the vertical electrical sounding and water quality analysis. The resistivity results revealed several probable isolated saltwater intruded pockets in the region with resistivity less than 70 Om. From the salinity analysis of water, the locations that are affected during February to May (summer) and throughout the year are identified. The wells that are located close to the coast (< 350 m) and at lower elevations (well bottom < +1 m) were found to be saline throughout the year. Also, wells along the banks of the river show considerable salinity (> 200 ppm) during the summer period from tidal inflow along the rivers. The water samples were also analyzed for chloride to bicarbonate ratios during December to May at all the monitoring wells and were found to be exceeding the allowable limit at several locations. The saltwater vulnerability maps are derived for the area by the index-based method using the hydrogeological parameters. The method was found to be effective while compared to the field observations. The results from the analysis indicate that the aquifer is medium to highly vulnerable to saltwater intrusion at majority of the locations. The impact of projected sea level rise by 0.25 and 0.50 m from the climate change is also assessed on the vulnerability of the region to saltwater intrusion. © 2012 American Society of Civil Engineers.Item Assessment of hydropower potential in Nethravathi river basin using SWAT model(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2015) Babar, S.; Shobhita, M.P.; Ramesh, H.Hydropower plants have the advantage of producing renewable and clean power, the renewable and reliable energy source that serves national environmental and energy policy objectives. Therefore, the development of hydropower plant and improvements of water management have essential in contributing to sustainable growth and energy production in developing countries like India. The present study is concerned with the development of methodology and assessment of hydropower potential in the Nethravathi River basin with the help of Remote Sensing and GIS. The drainage area covers about 3190 km2 at Bantwal gauging point, and most of the land cover of the basin is dominated by forest. The basin was divided into six sub-basins based on hydrology and topography using GIS tools. The climate over the basin is coastal humid tropical and receives an average annual rainfall of about 4000 mm. sub-basin discharges were estimated using the Soil Conservation Services (SCS) curve number method. To ensure the total discharge from six sub-basins computed from SCS curve number method, the flows were routed and simulated at the gauging location using Soil and Water Assessment Tool (SWAT). SWAT model was calibrated for monthly time steps from 1998–2001, and validated for 2002–2003. Flow-duration curves (FDC) were generated for each sub-basin to assess the dependable yield. The results have shown a good agreement between observed and the simulated flows. The available discharge at 75%, 80% and 90% of time for each sub-basin were extracted from the FDC. This result were used to calculate the hydropower potential in all the six sub-basins at Q75, Q80 and Q90, by integrating thematic layers using ArcSWAT. © 2015 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Streamflow response to land use-land cover change over the Nethravathi River Basin, India(American Society of Civil Engineers (ASCE), 2015) Babar, S.; Ramesh, H.Land use-land cover change (LULC) has considerable impacts on hydrologic response at the watershed level. Quantitative assessment of LULC impacts on runoff generations is vital for water resources development. The soil and water assessment tool (SWAT) model was used to study the effect of LULC change on streamflows. In addition to this, the present study proposed a newly developed flow-routing model called runoff coefficient routing model (RCRM). This new model is simple and requires limited data, such as precipitation, LULC and streamflows as compared to other models, which require meteorological and many more input data. The Nethravathi River basin was selected for testing the RCRM model with the SWAT model to study land use-land cover change on streamflows. The SWAT model and RCRM model have been calibrated for 2001-2005 and validated for 2006-2009 daily data. Results have shown that the simulated streams are well correlated with observed streamflows with a coefficient of correlation (R2) equal to 0.82 in calibration and 0.68 in validation period. Whereas, the RCRM model results have shown R2 of 0.81 and 0.66 in the calibration and validation period. Finally, the SWAT and RCRM results were compared. It is observed that the results of the RCRM model have shown a good agreement with SWAT model results of R2 equal to 0.99 and 0.98, respectively, in the calibration and validation period. The sensitivity analysis was also carried out based on Latin hypercube one factor-at-a-time (LH-OAT) method using the SWAT model and found 11 sensitive parameters out of 28 parameters. Model performance was carried out using the Nash-Sutcliffe model efficiency coefficient (NSE) and found 0.81 for calibration and 0.62 for the validation period in the SWAT model. RCRM has NSE of 0.79 and 0.63. The response of the streamflows for the year 2013 was simulated from the calibrated model. The results showed that the observed streamflows have shown good correlation with simulated streamflows with R2 values of 0.86 and NSE of 0.81. From the results, it is concluded that the runoff shows early response in the year 2013 compared to the year 2003. This is mainly due to changes in LULC, which shows the conversion of forest to agricultural area and increase in built-up area from 2003 to 2013. The effect of LULC change on the hydrological model parameters were calculated and observed a decrease in evapotranspiration (ET) of about 4.5%, an increase in runoff of about 0.9%, and an increase in groundwater of about 1.12%. In conclusion, the proposed RCRM in the present study simulates streamflows at par with the SWAT model with only few input data. Hence, the newly developed RCRM model would be used to study streamflows responses to LULC changes. © 2015 American Society of Civil Engineers.Item Assessment of soil erosion by RUSLE model using remote sensing and GIS - A case study of Nethravathi Basin(Elsevier B.V., 2016) Ganasri, B.P.; Ramesh, H.Soil erosion is a serious problem arising from agricultural intensification, land degradation and other anthropogenic activities. Assessment of soil erosion is useful in planning and conservation works in a watershed or basin. Modelling can provide a quantitative and consistent approach to estimate soil erosion and sediment yield under a wide range of conditions. In the present study, the soil loss model, Revised Universal Soil Loss Equation (RUSLE) integrated with GIS has been used to estimate soil loss in the Nethravathi Basin located in the southwestern part of India. The Nethravathi Basin is a tropical coastal humid area having a drainage area of 3128 km2 up to the gauging station. The parameters of RUSLE model were estimated using remote sensing data and the erosion probability zones were determined using GIS. The estimated rainfall erosivity, soil erodibility, topographic and crop management factors range from 2948.16 to 4711.4 MJ/mm·ha? 1hr? 1/year, 0.10 to 0.44 t ha? 1·MJ? 1·mm? 1, 0 to 92,774 and 0 to 0.63 respectively. The results indicate that the estimated total annual potential soil loss of about 473,339 t/yr is comparable with the measured sediment of 441,870 t/yr during the water year 2002–2003. The predicted soil erosion rate due to increase in agricultural area is about 14,673.5 t/yr. The probability zone map has been derived by the weighted overlay index method indicate that the major portion of the study area comes under low probability zone and only a small portion comes under high and very high probability zone. The results can certainly aid in implementation of soil management and conservation practices to reduce the soil erosion in the Nethravathi Basin. © 2015 China University of Geosciences (Beijing) and Peking UniversityItem 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 The impact of spatiotemporal patterns of land use land cover and land surface temperature on an urban cool island: a case study of Bengaluru(Springer International Publishing, 2019) Govind, N.R.; Ramesh, H.In most of the developing countries, man-made developments in the environment have led to the growing demand to contextualize the land use land cover (LULC) changes and land surface temperature (LST) variations. Due to the modification in the surface properties of the cities, a difference in energy balance between the cities and its nonurban surroundings is observed. The aim of this study is to analyze the spatial and temporal patterns of LULC and LST and its interrelationship in Bengaluru urban district, India, during the period from 1989 to 2017 using remote sensing data. Intensity analysis was performed for the interval to analyze the LULC change and identify the driving forces. The impact of LULC change on LST was assessed using hot spot analysis (Getis–Ord Gi* statistics). The results of this study show that (a) dominant LULC change experienced is the increase in urban area (approximately 40%) and the rate of land use change was faster in the time period 1989–2001 than 2001–2017; (b) the major transition witnessed is from barren and agricultural land to urban; (c) over the period of 28 years, LST patterns for different land use classes exhibit an increasing trend with an overall increase of approximately 6 °C and the mean LST of urban area increased by about 8 °C; (d) LST pattern change can be effectively analyzed using hot spot analysis; and (e) as the urban expansion occurs, the cold spots have increased, and it is mainly clustered in the urban area. It confirms the presence of an urban cool island effect in Bengaluru urban district. The findings of this work can be used as a scientific basis for the sustainable development and land use planning of the region in the future. © 2019, Springer Nature Switzerland AG.Item Predictive simulation of leachate transport in a coastal lateritic aquifer when remediated with reactive barrier of nano iron(Elsevier B.V., 2020) Divya, A.; Shrihari, S.; Ramesh, H.The current study focuses on determination of extent of groundwater contamination on a typical tropical coastal aquifer due to a landfill located at Vamnjoor in Dakshina Kannada district, India with the help of groundwater flow model, MODFLOW and MT3DMS when remediated with permanent reactive barrier of nano iron. The aquifer considered is a shallow, unconfined one with laterite soil which gets good rains during monsoon and will be dry during rest of the year. The adsorption by laterite soil has been considered. The specific yield and transmissivity were estimated to be 7.85% and 213m2/day respectively. After calibrating successfully with Nash–Sutcliffe efficiency 0.8, horizontal hydraulic conductivity was set as 7 m/day. Validation of model was then done with the field data and is applied for forecasting the spread of contaminant for anticipated future scenarios. The results show that in spite of retardation offered by lateritic soil, contaminant trail is expanding with a velocity of 0.15 m/day in downstream direction. When permeable reactive barrier of nano iron which can adsorb nearly 65% of chemical oxygen demand is installed, it is showing that the contaminant spread can be reduced to 400 mg/l at the observation well located at 1 km from landfill. Hence a comprehensive remedial alternative of permanent reactive barrier of nano iron can be recommended for preventing groundwater contamination from landfill leachate. © 2020 Elsevier B.V.Item Exploring the relationship between LST and land cover of Bengaluru by concentric ring approach(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Govind, N.R.; Ramesh, H.The present study aims at investigating the impact of land cover features in enhancing or mitigating Land Surface Temperature (LST) in a semi-arid tropical metropolitan city of Bengaluru, India. Spatial distribution of LST and land cover types of the area were examined in the circumferential direction, and the contribution of land cover classes on LST was studied over 28 years. Urban growth and LST were modelled using Landsat and MODIS data for the years 1989, 2001, 2005 and 2017 based on the concentric ring approach. The study provides an efficient methodology for modelling and parameterisation of LST and urban growth by fitting an inverse S-curve into urban density (UD) and mean LST data. In addition, multiple linear regression models which could effectively predict the LST distribution based on land cover types were developed for both day and night time. Based on the analysis of remotely sensed data for LST, it is observed that over the years, urban core area has increased circumferentially from 5 to 10 km, and the urban growth has spread towards outskirts beyond 15 km from the city centre. As urban expansion occurs, the area under the study experiences an expansive cooling effect during day time; at night, an expansive heating effect is experienced in accordance with the growth in UD in the suburban area and outskirts. The regression models that were developed have relatively high accuracy with R2 value of more than 0.94 and could explain the relationship between LST and land cover types. The study also revealed that there exists a negative correlation between urban, vegetation, water body and LST during day time while a positive correlation is observed during night. Thus, this study could assist urban planners and policymakers in understanding the scientific basis for urban heating effect and predict LST for the future development for implementing green infrastructure. The proposed methodology could be applied to other urban areas for quantifying the distribution of LST and different land cover types and their interrelationships. © 2020, Springer Nature Switzerland AG.