Groundwater

The groundwater potential zones in the Jaisamand Basin with a catchment area of 1813 km² have been delineated using various thematic layers including geomorphology, drainage, soil, land use, slope, topographic elevation, and net recharge. As the topography is highly undulating with rolling uplands and in-filled valleys, the velocity of runoff is high whenever the rainfall occurs during the monsoon months. Suitable relative weights have been assigned to the thematic layers on a scale of 1–5 based on their influence on the occurrence of groundwater potential, and thereafter integrated using ILWIS GIS software. The analysis indicated a net recharge of 2–5 cm per year takes place in about 62% of the study area. The study area has been divided into four groundwater potential zones, viz. ‘good,’ ‘moderate,’ ‘poor,’ and ‘very poor,’ which covers 12.82, 49.65, 33.21, and 4.32% of the study area. Since 37.53% of the study area has poor-to-very poor groundwater potential, immediate measures are required for ensuring sustainable groundwater management in the basin through supply–demand management as well as artificial groundwater recharge of potential aquifers. About 15% percent of the study area is suitable for artificial recharge in the southern part of the basin.

Groundwater is one of the most important natural resource used for drinking, industrial, agriculture, etc. Understanding spatial and temporal variations of groundwater level throughout the basin is essential for sustainable development of groundwater resources. The objective of the present study is to analyze the spatial and temporal variations of groundwater levels in the Wainganga sub-basin. Mann–Kendall and ordinary kriging methods were used to analyze the groundwater levels with space and time. Pre- and post-monsoon groundwater levels from 1991 to 2012 were used for analysis. For the last 22 years, from the spatial variation maps, small fluctuations were observed in groundwater levels and it is found to be deeper, particularly in industrial areas. Also, temporal variation of groundwater level shows the decreasing trends.

Assessment of spatio-temporal variation provides a principal source of information regarding groundwater recharge, storage and discharge. Spatio-temporal variation of groundwater level (GWL) in Raipur city has been studied using statistical and graphical methods. Monthly trend of GWL has been investigated using Mann–Kendall test and Sen’s slope estimator. The monthly GWL data of thirty observation wells (dug well) of Raipur city for the period 2010–2014 have been used for the study. The minimum and maximum GWL has been found out to be 0.84 m below ground level (bgl) which is 267.98 m above mean sea level (amsl) and 16.61 m bgl (271.53 m amsl). Contour map shows that average GWL varies between 1.74 and 13.80 m bgl (i.e. 280.34 m to 287.12 amsl) during pre-monsoon and 1.64 m to 6.75 m bgl (i.e. 279.92 m to 282.54 m amsl) during post-monsoon. GWL is shallower in central part of the city, whereas deeper GWL has been observed in western and northern part of the city. The groundwater contour maps depict that the groundwater flow direction is towards north and west. The results of trend analysis reveal that no significant trend is detected at 5% significance level except few locations.

Land use and land cover changes have been undergoing at a rapid rate universally. Anthropogenic activities where human intervention is involved is been considered as a major driver for land use changes. This type of advancement in land activity has caused depletion of natural resources more so groundwater table. There is a great need for assessment of groundwater profile at local level. Groundwater is maximally harnessed for many water use purposes in Dakshina Kannada district, Karnataka. This study aims to analyze and quantify the effect of land use/land cover (LU/LC) transformations along a time scale with the fluctuating groundwater levels. Groundwater level information of the year 2003 and 2013 from observation wells and satellite imagery from Landsat with ETM 7 and OLI sensors were used. Kriging, a geostatistical method of interpolation, used well data as points taken at different locations (29 wells) all over the district and created a continuous surface using interpolation with the estimate of error. LULC map of 2003 and 2013 was derived from classification of TM images using supervised, parametric maximum likelihood classifier. Area is broadly categorized into four classes, namely vegetation, urban areas, water, and other category. Accuracy assessment of this classification yielded kappa statistics of greater than 0.8 for both the images and overall accuracy greater than 90%. Further, relationship between LULC and groundwater level is inferred with the help of 1 by 1 km grid. Rainfall and stream network were used in ascertaining the sensitive areas in terms of groundwater that hold a hydrogeological importance. It was inferred from the study that the groundwater depletion to the extent of 2 m has been evident in the urban areas with an increase in built-up greater than 25 acres per 250 acres. These fluctuations are evident in the northwest and south regions of the district compared to the other areas. Moreover, these hydrogeologically sensitive areas for recharge need protection from further development activities.

The aquifer systems in the Indo-Gangetic alluvial river systems are recharged by rains and also by seepage from the irrigation canal commands. Groundwater resource is threatened due to rising water demand for advancement in the agricultural sector together with rapid industrialization. Utilization of groundwater at a rate greater than annual recharge constitutes unsustainable groundwater development. The problems of excessive groundwater extraction in the tail reaches of canal commands are common. In such areas, there is considerable potential for sustainable groundwater management through groundwater system modelling. Present work simulates the groundwater system in Sai–Gomti interfluve region which is a part of Indo-Gangetic alluvial plain in Uttar Pradesh, India. Groundwater simulation was carried out using Visual MODFLOW. The study area comprises mainly of agricultural land and is part of Sharda Sahayak Canal System in Uttar Pradesh. Visual MODFLOW was calibrated and validated for water level data available for 9 years (2005–2013). The effect of change in recharge rate and withdrawal rate is also investigated to predict the corresponding changes in water levels. Groundwater level was predicted beyond five years for future. Deterministic as well as fuzzy sensitivity analysis is performed to characterize uncertainty in predicted groundwater levels due to possible uncertainty in hydraulic conductivity and porosity.

In this article, aquifer vulnerability has been assessed by incorporating the major geological and hydrogeological factors that affect and control the groundwater contamination using GIS-based DRASTIC model. This work demonstrates the potential of GIS to derive a vulnerability map by overlying various spatially referenced digital data layers (i.e., depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity) that portray cumulative aquifer sensitivity ratings across a tannery belt affected by the untreated 80 functional tannery effluents and located in a hard rock area (granitic terrain) in Southern India. It provides a relative indication of aquifer vulnerability to contamination. It has been also cross-verified with the association of selective hydrochemical parameters such as total dissolved solids (TDS), Cl⁻, \({\text{HCO}}_{3}^{ - }\), \({\text{SO}}_{4}^{2 - }\), and Cl⁻/\({\text{HCO}}_{3}^{ - }\) molar ratios. The results have recognized four aquifer vulnerability zones based on DRASTIC vulnerability index (DVI), which ranged from 39 to 132. It has been deduced that approximately 18, 25, 34, and 23% of the area lies in negligible, low, medium, and high vulnerability zones, respectively. It shows that about 43% of the study area is under negligible and low vulnerable area where TDS varies from 650 to 1,796 mg/l and Cl⁻ varies from 106 to 148 mg/l. It occupies in the southern and northern most parts, whereas about 57% area in central part is moderately and highly contaminated due to the disposal of tannery industries and is more prone to aquifer vulnerability, where the high ranges of TDS (2,304–39,100 mg/l), Na⁺ (239–6046 mg/l), and Cl⁻ (532–13,652 mg/l) values are well correlated with the observed high vulnerable zones. The Cl⁻/\({\text{HCO}}_{3}^{ - }\) molar ratios (=1.4–106.8) of the high vulnerable zone obviously indicate deterioration of the aquifer contamination due to the tannery effluents. It is realized that GIS is an effective platform for aquifer vulnerability mapping with reliable accuracy, and hence, the study is more useful for environmental planning and predictive groundwater management in granitic terrain.

Proper groundwater recharging may drastically change the scenario of groundwater availability of the area. It needs appropriate groundwater recharge locations, which can be prepared by using satellite data and GIS. Eight blocks of five districts including Bemetara in Chhattisgarh are reported to be semi-critical. Average groundwater development of Bemetara district is reported to be 63.24%. Looking to the need of groundwater recharge plan for Bemetara district a study on groundwater recharge planning was carried out in the Department of Soil and Water Engineering, Faculty of Agricultural Engineering, IGKV, Raipur. Accordingly, thematic maps were superimposed to identify the appropriate locations for artificial groundwater recharge structures. Various thematic maps including district and block boundaries, drainage, slope, soil texture, lineaments, geology and water level depth were generated in the environment of GIS. A satellite image, IRS P6 LISS IV, was classified using supervised classification method to generated land use map of the area. Different structures and their sizes were decided on the basis of topography and drainage pattern. The upper, middle and lower reaches of drainage lines were considered for different sizes of check dam. The site for percolation tank was identified for groundwater recharge. The field survey of study areas was also carried out to find out the suitability of proposed artificial groundwater recharge structures. It is concluded that suitable sites for artificial recharge structures in these districts were found to be 68%. Finally, 130 locations for check dam and 59 locations for percolation tank in Bemetara district were identified. The subsurface storage space was estimated on the basis of thickness of available vadose zone. The vadose zone of 285 Mm³ is available for artificial recharge in the Bemetara district. The volume of water required for artificial recharge was found to be 379 Mm³ for this district. It was found that sufficient volume of water required for artificial recharge is available. Availability of source water to recharge the subsurface reservoir were found to be 1099 Mm³ in the form of non-committed surplus run-off out of which 30% (329.67 Mm³) is considered as surplus monsoon run-off which is available for artificial recharge.

The quality of groundwater in shallow alluvial aquifers exhibits wide range of variations, due to deltaic nature of the deposits, paleochannel and drainage conditions. In alluvial aquifers, the deeper aquifers are invariably saline. Demand for freshwater for drinking purposes in deltas is increasing day by day. Keeping in view such conditions, paleochannels contain and yield freshwater in significant quantities if they have hydraulic connection from the original river course from where they get recharged. One such major paleochannel of central Godavari delta has been identified by Andhra Pradesh State Ground Water Department during their investigations. The present paper deals with characterization of hydrochemistry in and around identified paleochannel spatially and temporally. The chemical analysis indicated that the electrical conductivity (EC) of paleochannel water is less than groundwater. Detailed hydrochemistry of canal water, drain water and river water is presented in the paper. The hydrochemistry of paleochannel water indicated that there is no significant seasonal change in paleochannel water, and most of the samples belong to Ca-HCO₃ type. The recharge to the paleochannel is studied by analysing stable isotopes (δ¹⁸O and δD) in groundwater, rainwater, canal water and river water. It is found that recharge to the paleochannel is mainly from river water and canal water than from rainwater. Optimum utilization planning of this limited freshwater resources in identified paleochannel is of immense importance, and it is also necessary to protect its quality from anthropogenic activities.

In recent years, large-scale reduction in the forest cover is observed all over the country due to various reasons, particularly in the humid tropics. However, there are concerted efforts by government departments and NGO’s to bring back the degraded forests to original position through plantation and related agro-forestry activities. Reforestation/afforestation is often recommended as a means of reducing the increased surface water losses associated with soil degradation, returning water to the roots through the soil profile, thereby ultimately restoring base flow. Most of the rehabilitation programs often adopt fast-growing exotic species such as, Eucalyptus spp., Acacia auriculiformis. Many researchers raised concerns over the increased afforestation with exotic forest species on water availability. However, such studies are quite sparse, particularly in humid tropical climates. The Western Ghats in south India, is a treasure house for number of rivers which feeds locally and plays a significant role in socio-economic growth of this part of the country. It is reported that, there is a tremendous change in land use/land cover mainly because of deforestation and also due to afforestation with exotic species such as A. auriculiformis. In spite of such wider change in the land use/land cover, studies on its impact on groundwater resources are lacking. Therefore, the present study has been carried out to understand the influence of land use/land cover changes on groundwater in parts of Malaprabha catchment, a tributary of River Krishna accentuating hydrological and hydrogeological investigations. Rainfall and groundwater level data have been collected from State and Central organizations. Groundwater recharge was estimated using empirical and Groundwater Estimation Committee methods. A numerical model, soil water infiltration movement model (SWIM), was applied to estimate the groundwater recharge under different land covers. It was observed that the groundwater recharge is mainly dependent on the rainfall pattern and land use/land cover changes. The forested areas have shown relatively higher recharge as compared to degraded and agriculture lands.

Assessment of groundwater quality is equally important as its quantity. Dependency on groundwater increases with population, hence it is necessary to quantify the causes and sources of groundwater pollution. The possible contaminants in groundwater are practically unlimited; a wide range of contaminants are found in groundwater. The main sources and causes of groundwater pollution are municipal, industrial and agricultural. The objective of the present study is to enumerate on the sources and causes of groundwater pollution in relation with municipal usage within the Nagpur city. Finally, relation between Land use/Land cover and groundwater pollution has been established using geographical information system (GIS).

This paper presents the development of a one-dimensional numerical model that can be used for quantifying groundwater contamination due to discharge from a landfill. The model can be used for the simulation of contaminant transport in aquifers. The present goal is to assess leachate migration from a landfill in order to control its environmental impacts on groundwater. Leachate is one of the main causes of surface and ground water contamination. A poorly designed landfill can create contamination of groundwater. As water percolates through the landfill, contaminants are leached from the solid waste. A finite difference model is developed and compared with analytical model to study the leachate migration for a one-year period for a case study. A column study is also conducted to determine the aquifer parameters. Due to the uncertainty in the input parameters, the result obtained from the numerical modeling may not give the exact behavior. A code was developed in Matlab to link numerical model with Monte Carlo Simulation and the uncertainty in the concentration was obtained.

Environmental geochemical studies are carried out to assess the groundwater quality and identification of hydrogeochemical process in hard rock terrain of Bhongir watershed nearer to the Greater Hyderabad. A total of thirty-eight groundwater samples were collected and analysed for important physicochemical parameters, anions and cations. The analytical data of alkalis (Na⁺ and K⁺) and alkaline earths (Ca²⁺ and Mg²⁺), reveal that high concentration of Na⁺ than others (Na > Ca > Mg > K) is probability due to the loss of Ca²⁺ and Mg²⁺ and gain of Na⁺ by the cation exchange process. Among the anions, bicarbonate is identified in majority of the samples in the following order HCO₃ > Cl > SO₄ which confirms that all carbonate minerals might have been dissolved and leached to the groundwater system. Most of the samples (81%) are exceeding the WHO allowable limits of electrical conductivity for drinking. The data sets further suggest that the water chemistry in the study area is not homogeneous and influenced by complex contamination sources and geochemical processes. Besides, highest concentration of nitrate (565.7 mg/L), sulphate (414 mg/L) and chloride (1444 mg/L) firmly suggests the impact of agricultural activities such as irrigation return flow, fertilizer application on water chemistry. The elevated concentrations of fluoride (i.e. maximum 4.1 mg/L) in most of the water samples (66%) reveal the origin and geochemical mechanisms, i.e. rock–water interaction is driving its enrichment. As majority of the parameters are above the permissible limit, the groundwater is not potable for drinking.

Nitrate percolates through deep vadose zone before entering groundwater. In the previous few years, researchers have only focused on the movement of nitrate up to the root zone depth of the crops. Few studies have been done on movement of nitrate in unsaturated region beyond root zone depth. In the present paper, spatial and temporal nitrate transportation in deep vadose zone has been studied. A case study, considering the hydrogeological features of alluvial plain, has been done for nitrate transportation in deep vadose zone. Heterogeneity in the subsurface layers of vadose zone has also been incorporated in this study. The fate of nitrate plume for varying concentration has been studied. The results in this study mainly quantify nitrate flux along with water flux, pressure head, and water content in various heterogeneous layers before entering groundwater table. Simulation results suggest that heterogeneity with dual permeability has a profound impact on nitrate transport in vadose zone.

River bank filtration is a sustainable solution for drinking water quality and quantity problems in Haridwar, Uttarakhand. Riverbank filtration (RBF) is an efficient and low-cost natural alternative technology for water supply application, in which surface water contaminants are removed or degraded as the infiltrating water moves from the river/lake to the pumping wells. The removal or degradation of contaminants is a combination of physicochemical and biological processes. This paper presents an investigation to the full set-up of 22 RBF large diameter (10 m) caisson wells located along the bank of River Ganga in order to supply portable drinking water for Haridwar (112,617 persons residing permanently in the main city). These 22 RBF large diameter (10 m) caisson wells were constructed along the bank of River Ganga at Haridwar, each 7–10 m deep, and are located 50–450 m from the Ganga River or the Upper Ganga Canal. Water samples from River Ganga as induced surface water, from Upper Ganga Canal (UGC), groundwater (open well) and from RBF wells were collected and analysed for pre-monsoon and post-monsoon period. Quality measurements of physical, chemical and microbiological characteristics were obtained. Comparison of water supplied from RBF wells with surface, UGC and background natural groundwater for the investigated Haridwar site has proven the effectiveness of RBF technique for potable water supply in Haridwar district of Uttarakhand. Physicochemical and microbiological characteristics of the produced water are better than the allowable standards (IS 10500) for drinking purposes or recommended WHO limits. The results prove effectiveness of RBF method for sustainable drinking water supply in feasible locations.

The study is an attempt to evaluate the behaviour of constituents/pollutants moving with groundwater. Three examples having field relevance have been demonstrated in the study. Dispersivity, adsorptivity and decay which are primary parameters affecting the transport phenomena have been considered. The dispersivity which is the main characterizing parameter in groundwater solute transport problems has been considered for sensitivity analysis. It has also been attempted to quantify errors when a when a 3-D problem is simplified to a 2-D problem and a 2-D problem to a 1-D problem for convenience. The result indicated that one-dimensional analytical and numerical solution of transport equation compares well but simplifying a two-/three-dimensional transport problem to a one-dimensional problem leads to error due to transverse dispersion. Close to the source, advection dominates, whereas away from it the dispersion phenomena dominate. It was also seen that transverse dispersivity becomes prominent as distance increases from the source.

A study was conducted during pre- and postmonsoon seasons of the years 2011 and 2012 in Rajsamand district of Rajasthan to prioritize the management of groundwater quality-related problems. The whole district was divided into 6 km × 6 km square grids, and from each grid, one open dug well was selected randomly. The locations of wells were recorded with the help of global positioning system (GPS). The groundwater samples were drawn from 128 selected open dug wells and analysed for standard water quality parameters, and it was found that the TDS of groundwater of Rajsamand district ranged from 164 to 8600 and 152 to 7840 mg kg⁻¹ in premonsoon seasons with the mean value of 1508 and 1425 mg kg⁻¹ in the years 2011 and 2012, respectively. In postmonsoon seasons, the TDS varied from 120 to 5810 and 122 to 5980 mg kg⁻¹ with the mean values of 1142 and 1154 mg kg⁻¹ in the years 2011 and 2012, respectively. The pH of groundwater in premonsoon varied from 6.30 to 8.20 and 6.40 to 8.10 with average values of 7.16 and 7.17 in the years 2011 and 2012, respectively. During postmonsoon seasons, the pH value varied from 6.70 to 8.30 and 6.90 to 8.20 with the mean values of 7.42 and 7.36 in the years 2011 and 2012, respectively. The electrical conductivity of groundwater of Rajsamand district varied from 0.25 to 13.44 and 0.23 to 12.20 dSm⁻¹ with the mean values of 2.35 and 2.21 dSm⁻¹ in premonsoon, whereas in postmonsoons the EC of groundwater varied from 0.18 to 9.08 and 0.20 to 9.40 dSm⁻¹ with mean values of 1.78 and 1.81 dSm⁻¹ in years 2011 and 2012, respectively. The minimum EC was found in Kumbhalgarh, whereas the maximum was recorded in Railmagra block in both years.

Nitrate leaching from agricultural soils is a major concern to the groundwater, surface water bodies, and environment and also affects the farmers’ economy. The present study investigated the effect of native soil organic carbon and biochar amendment on the leaching of nitrate using a laboratory column study. The experiment was conducted taking two soil types of central India (Inceptisol and Vertisol differing in soil texture, viz. Loamy and clay texture). In each soil type, three native SOC levels (C ₁: high SOC, C ₂: medium, and C ₃: low SOC) and four biochar amendment levels were taken in three replications in a factorial design. The four levels of biochar amendment were 0 (B ₀), 5 (B ₅), 10 (B ₁₀), and 20 (B ₂₀) g biochar kg⁻¹ of air-dry soil. There was a significant effect of soil C (p < 0.01) and biochar (p < 0.01) amendment on the NO₃ ⁻-N leached, and the total dissolved salt (TDS) leached in both soil types. In the Inceptisol, NO₃ ⁻-N leaching increased with reduction in native SOC content, whereas the reverse trend was observed in the Vertisol. Biochar amendment reduced NO₃ ⁻ leaching in both the soils, though the effect was higher in the Inceptisol. In both the soils, a significant effect of SOC level on leachate pH was observed with reducing pH with decrease in SOC level. As compared to control, the extent of reduction in the TDS leaching varied from 13 to 18% under biochar amendment in the Inceptisol and by about 5–6% in the Vertisol.

Variations in availability of water with respect to time, quantity, and quality are playing a very significant role in the development of economy of a country. For the different uses, one may require different criteria of water quality as well as standard methods for reporting and comparing results of water analysis. Groundwater and other water bodies in the region of central India are getting contaminated due to numerous types of discharge by the human activities, residential, municipal, commercial, industrial, and agricultural activities. Bhopal, the capital of province of the Madhya Pradesh in India, has a number of water bodies. Laharpur reservoir is one of them. An attempt is made to investigate the seasonal variation in groundwater quality in and around the area of the Laharpur reservoir. The study has revealed from the analyzed results of collected groundwater samples that certain parameters, namely EC, TH, TDS, BOD, chlorides, were exceeding the desirable limit throughout the investigation period in all locations. This is due to the leaching of contaminants into the groundwater. Based on the findings, it is suggested to the local government that discharged wastewater from the sewage of residential and local industrial area must be treated properly as per the standard to avoid its adverse impact on the human health of the region.