Rock Terrain Research Articles

Groundwater flow modeling in the basaltic hard rock area of Maharashtra, India

The ecological sustainable development and planning of groundwater resources is an excessive challenge for many countries currently facing water insufficiency. The main focus of this work was to determine the direction of groundwater flow, head value, and water level using the steady-state finite difference model (MODFLOW software) in basaltic formations in Maharashtra, India. The MODFLOW model was integrated with ground data using Geographic Information System (GIS) for sustainable groundwater resource management in the hard rock terrain. The MODFLOW-2005 model simulated the interaction between heads and time in 2014–18 by steady-state conditions. In this present study, four observation wells were selected. During the field survey, four observation wells have been monitored regularly as per the Central Groundwater Board guidelines. MODFLOW software has been conceptualized as a double-layered rigid and fractured aquifer area feast over 18,312 m × 11,265 m area. This research demonstrates that the integration of GIS, conventional fieldwork, and mathematical model can support to understand groundwater demand and supply in a better way.

Understanding the hydrogeochemical processes and physical parameters controlling the groundwater chemistry of a tropical river basin, South India.

Detailed investigation on hydrogeochemistry of hard rock terrains is important to identify the major geochemical processes and the source of ionic constituents in groundwater. The present study is carried out to understand the hydrogeochemistry of groundwater resources and the major hydrogeochemical processes, controlling the concentration of major ions in groundwater in the Kallada River Basin (KRB), South India. About 166 groundwater samples were collected from KRB during pre- and post-monsoon of 2016 for hydrogeochemical analysis. Most of the groundwater samples in KRB were within permissible limits of drinking water quality. The dominant groundwater types during pre-monsoon were Ca2+-Mg2+-Cl- which was changed to Na+-Cl- during post-monsoon. This is supported bythe inverse relationship of depth of wells and change in EC during pre- and post-monsoon periods. Rock-water interaction processes such as reverse ion exchange and silicate weathering are major geochemical processes responsible for the hydrogeochemical signatures of KRB. The shallower wells (< 10 m) show strongest relation with the water types Na+-HCO3- and Ca2+-Mg2+-Cl- which have been changed to Na+-Cl- and Ca2+-Mg2+-HCO3- during post-monsoon. However, in deeper wells, Na+-Cl- is the dominant type of water during both seasons. The hierarchical cluster analysis displays different hydrogeochemical associations representing diverse physicochemical parameters both spatially and temporally. This study could shed light on diverse hydrogeochemical processes which are responsible for the hydrogeochemistry in KRB. Major hydrogeochemical processes in the Kallada River Basi.

Geoelectrical Survey for Evaluation of Groundwater Potential Within the Basaltic Terrain of Chikotra River Basin, Maharashtra (India)

Geoelectrical data was acquired using Wenner array over 23 sites with constant electrode separation of 70 m over Chikotra Basin, Dist. Kolhapur, Maharashtra (India). The spatial variation maps of resistivity at depths from 2 to 70 m were plotted using Inverse Distance Weighted (IDW) technique for interpolation in ArcGIS 10.5 to obtain a comprehensive subsurface hydrogeological representation of the study area. High resistivity (&gt;140 Ωm) up to 20m depth, indicative of massive basalts is deciphered towards the NE part of the study area, while the NW sector reveal low resistive (up to 40 Ωm) feature at shallow depths due to fractured basalts, thus conducive for groundwater exploration. Alluvium deposits and columnar jointed basalts in the central part depicts as EW trending conductive (&lt; 30 Ωm) feature suggesting prospective groundwater zone. Low resistivity (6-50 Ωm) from shallow to deeper depths (up to 70m), in the southern region can be identified as potential aquifer system. Longitudinal geoelectric cross-sections are generated over four profiles to identify the lateral and vertical variation in geology and groundwater potential zones. The western and central part of the northern profile (A-A') is highly resistive with resistivity of the order of 80-140 Ωm constituting compact basalts and thus devoid of water. Low resistive zone (30 Ωm) in the eastern part suggests groundwater at shallow depths. Low resistivity zones ranging from 10-50 Ωm is observed at different depth levels over the central profile (B-B') which can be tapped for groundwater exploitation. Several sites over profiles C-C' and the southern-most D-D' suggest promising aquifer zones. Because defining prospective groundwater zones in hard rock terrain is difficult, it’s crucial to look into a river basin’s hydrogeological arrangement early on in the planning process.

Integration of ERT, IP and SP Methods in Hard Rock Engineering

Investigation of a hard rock site for the development of engineered structures mainly depends on the delineation of weathered and unweathered rock, and the fractures/faults. Traditionally, borehole tests are used in such investigations. However, such approaches are expensive and time-consuming, require more equipment, cannot be conducted in steep topographic areas, and provide low coverage of the area with point measurements only. Conversely, geophysical methods are non-invasive, economical, and provide large coverage of an area through both vertical and lateral imaging of the subsurface. The geophysical method, electrical resistivity tomography (ERT), can reduce a significant number of expensive drilling tests in geotechnical investigations. However, a geophysical method alone may provide ambiguity in the interpretation of the subsurface, such as electrical resistivity cannot differentiate between water and clay content. Such uncertainty can be improved by the integration of ERT with induced polarization (IP). Similarly, self-potential (SP) can be integrated with other geophysical methods to delineate the groundwater flow. In this contribution, we integrated three geophysical methods (ERT, IP and SP) to delineate the weathered and unweathered rock including the weathered/unweathered transition zone, to detect the fractures/faults, and to map the groundwater flow. Based on ERT, IP and SP results, we develop a geophysical conceptual site model which can be used by site engineers to interpret/implement the findings for build-out. Our approach fills the gaps between the well data and geological model and suggests the most suitable places for the development of engineered structures in the hard rock terrains.

Influence of climate on groundwater fluoride in different climatic domains in a hard rock terrain of Sri Lanka: implications to community health.

Health risks associated with excessive intake of fluoride through drinking water are one of the geoenvironmental health problems observed in many parts of the world, mainly in countries of the humid tropical belt, including Sri Lanka. Fluoride-related health problems are widespread in the dry climatic region compared to the wet climatic zone of Sri Lanka. The potential health risks of fluoride for communities in a river basin which drains through two climatic zones, viz. wet and dry zones, were investigated in this study. Sixty-three groundwater samples were collected from wells in the Walawe river basin during pre- and post-monsoon periods. From collected samples, ten selected samples were analyzed for their tritium (3H) levels to find out the approximate resident time of groundwater. In the river basin, the dry zone segment is characterized by elevated levels of fluoride (> 1.0mg/L) in groundwater. Groundwater fluoride in the region was primarily of geogenic origin. The tritium values showed older groundwater contained higher fluoride levels, showing a increased dissolution of fluoride-bearing minerals. The hazard quotient (HQfluoride) showed that about 45% ofpre- and 55%of post-monsoon groundwater samples in the dry zone area were unsuitable for drinking purposes for school children who are vulnerable to non-carcinogenic risks and dental fluorosis. This study emphasizes the need for continuous water quality monitoring and mitigation measures to ensure the health of residents.

Joint geophysical prospecting for groundwater exploration in weathered terrains of South Guangdong, China.

Groundwater occurrence in a hard rock terrain is strongly controlled by the weathered/fractured zones. However, delineation of such zones is a challenging task given their structural heterogeneity. Traditionally, large numbers of well tests are conducted to assess the subsurface formation. But, such tests suffer from efficiency in terms of cost, time, and data coverage. Non-invasive geophysical methods can be the best alternative of expensive drilling methods. However, a geophysical method alone is ambiguous to interpret the highly heterogeneous subsurface formation. In this study, joint application of electrical resistivity tomography (ERT), magnetic method, and joint profile method (JPM) was conducted for groundwater exploitation in a weathered terrain of South Guangdong, China. ERT, magnetic, and JPM data were acquired along different geophysical profiles via a variety of survey parameters. The interpreted 2D models of electrical resistivity and magnetic data coupled with the local accessible boreholes and hydrogeological information constrain the subsurface geologic formation into four discrete layers with specific electrical resistivity range, i.e., topsoil cover, highly weathered saturated layer, semi-weathered saturated layer, and un-weathered substratum. Incorporation of JPM (ER, SP, and IP methods) with ERT and magnetic models reveal three faults (F1, F2, and F3) and several saturated intense fractures/discontinuities. The groundwater reserves associated with the weathered/fractured rock were estimated via hydraulic parameters, namely hydraulic conductivity and transmissivity. The results suggest that high-yield groundwater resources are found within the weathered/fractured zones. Geophysical results of this joint application fit pretty well to the local hydrogeological data of the study area. Our novel approach reduces any ambiguity caused in the geophysical interpretation and provides clearer insight of the subsurface formation with more confident solutions to the most challenging problems of the hard rock sites. This hydrogeophysical study provides important contributions to groundwater exploration in areas where weathering has significant effects on the hard rock aquifer system. Compared with traditional methods, this approach is more advantageous for assessment of groundwater resources in hard rock terrains.

Use of Earth Observation Images and GIS Techniques for Groundwater Exploration in Hard Rock Terrain

Prolonged drought and improper maintenance of water resources increased the demands on ground-water supplies resulting are focuses for the need to evaluate ground-water resources in the hard rock terrain. In recent years, Remote-Sensing methods have been increasingly recognized as a means of obtaining crucial geo-scientific data for both regional and site-specific investigations. This work aims to develop and apply integrated methods combining the information obtained by geo-hydrological field mapping and those obtained by analyzing multi-source remotely sensed data in a GIS environment for better understanding the Groundwater condition in hard rock terrain. In this study, digitally enhanced Landsat ETM+ data was used to extract information on geology, geomorphology. Hill-Shading techniques are applied to SRTM DEM data to enhance terrain perspective views and to extract Geomorphological features and morphologically defined structures through the means of lineament analysis. A combination of Spectral information from Landsat ETM+ data plus spatial information from SRTM-DEM data is used to address the groundwater potential of alluvium, colluvium and fractured crystalline rocks in study area. The spatial distribution of groundwater potential zones shows regional patterns related to lithologies, lineaments, drainage systems and landforms. High yielding wells and springs are often related to large lineaments and corresponding structural features such as dykes. The results demonstrate that the integration of remote sensing, GIS, traditional fieldwork and models provide a powerful tool in the assessment and management of water resources and development of groundwater exploration plans.

Use of earth observation images and GIS techniques for groundwater exploration in hard rock terrain

Prolonged drought and improper maintenance of water resources increased the demands on ground-water supplies resulting are focuses for the need to evaluate ground-water resources in the hard rock terrain. In recent years, Remote-Sensing methods have been increasingly recognized as a means of obtaining crucial geo-scientific data for both regional and site-specific investigations. This work aims to develop and apply integrated methods combining the information obtained by geo-hydrological field mapping and those obtained by analyzing multi-source remotely sensed data in a GIS environment for better understanding the Groundwater condition in hard rock terrain. In this study, digitally enhanced Landsat ETM+ data was used to extract information on geology, geomorphology. Hill-Shading techniques are applied to SRTM DEM data to enhance terrain perspective views and to extract Geomorphological features and morphologically defined structures through the means of lineament analysis. A combination of Spectral information from Landsat ETM+ data plus spatial information from SRTM-DEM data is used to address the groundwater potential of alluvium, colluvium and fractured crystalline rocks in study area. The spatial distribution of groundwater potential zones shows regional patterns related to lithologies, lineaments, drainage systems and landforms. High yielding wells and springs are often related to large lineaments and corresponding structural features such as dykes. The results demonstrate that the integration of remote sensing, GIS, traditional fieldwork and models provide a powerful tool in the assessment and management of water resources and development of groundwater exploration plans.

Quantitative Geomorphological Parameters Analysis for the Aynalem- Illala Streams, Tigray, Northern Ethiopia

Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge. The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.

Quantitative morphometric infer in the hard rock Terrain based on SRTM-DEM and GIS-Chintamani Watershed, Chikkaballapur District, Karnataka, India

Quantitative morphometric infer in the hard rock Terrain based on SRTM-DEM and GIS-Chintamani Watershed, Chikkaballapur District, Karnataka, India

Suggestive artificial recharge structures in hard rock terrain areas for sustainable groundwater conservation using remote sensing, GIS, and geophysical technique

Suggestive artificial recharge structures in hard rock terrain areas for sustainable groundwater conservation using remote sensing, GIS, and geophysical technique

Delineating the characteristics of saline water intrusion in the coastal aquifers of Tamil Nadu, India by analysing the Dar-Zarrouk parameters

Tuticorin, located in the southeastern part of Tamil Nadu, is a coastal aquifer on which Vertical Electrical Sounding (VES) was conducted, thereby analysing the interpreted subsurface resistivity layer parameters covering around 112 km2 area of the study region. VES is an essential tool for investigating hard rock terrains of coastal aquifers and perceive an idea about the groundwater quality. In this study, Dar-Zarrouk (D-Z) parameters like longitudinal conductance (Sc), transverse resistance (Tr) and anisotropy (λ) are analysed as these are well-established parameters in delineating the occurrence and distribution of both fresh and saline water aquifers. These parameters are also very persuasive in investigating complex subsurface parameters (resistivity and conductivity) within saline water intruded coastal region environment. After conducting a thorough survey, the resistivity results reflect that the sediments are enriched with saltwater, clay with moderate freshwater and freshwater-bearing formations. The analysis shows that the D-Z parameters offer a helpful and assured answer in demarcating the saline, moderate fresh, and freshwater aquifers. Therefore, the behaviour and patterns of the D-Z parameters in space established the existence of saline water and freshwater aquifer structures in the coastal aquifers over a vast area.

Groundwater quality of an hard rock aquifer in the Subledu Basin of Khammam district, India

Hard rock aquifers of Indian peninsula are loaded with excess nitrate due to heavy use of fertilizers during irrigation and excess fluoride due to the geogenic contamination. This study is focused on the groundwater quality in Subledu Basin in view of the large-scale use of groundwater for both irrigation and drinking purposes as no such study was carried out earlier in the basin. The study area is located at Khammam district, Telangana state, India, which is a hard rock terrain mostly covered with granites and gneisses. Twenty-two groundwater samples were collected covering the entire basin in the month of May 2019 from running hand pumps for analyzing the major anions and cations in the groundwater. The samples were analyzed by using standard gravimetric method for evaluation of total dissolved solids; titrimetric methods to analyze carbonates, bicarbonates and chloride; UV spectrometric method for estimation of nitrate; and ion-selective electrode method for fluoride and spectrophotometer for sulfate and phosphate. These chemical constituents are used to calculate parameters, namely total hardness, sodium adsorption ratio, residual sodium carbonate, sodium percentage, Kelley’s ratio and magnesium hazard. The spatial distribution maps of important chemical constituents are prepared by using the contour maps created by utilizing the inverse distance weighted interpolation tool in the Geographical Information System. The excess fluoride values of 2.84 mg/l, 2.76 mg/l and 1.87 mg/l are observed in the villages of Pocharam, Kistapuram and Turakagudem, respectively, as against the maximum permissible concentration of 1.5 mg/l prescribed by World Health Organization. Excess use of fertilizers for agriculture is causing the nitrate pollution of groundwater in more than 50% of the samples with concentrations ranging from a minimum of 2 mg/l to a maximum of 460 mg/l in the villages of Medidapalle and Bachodu. It is identified that the total hardness is ranging between 200 and 820 mg/l which is very high when compared with the Bureau of Indian Standards. Based on sodium adsorption ratio, residual sodium carbonate, Kelley’s ratio, and sodium percentage analyses, two samples were not suitable for irrigation. Similarly, 13 samples are not suitable for drinking water purposes based on the excess presence of fluoride and nitrate. Groundwater quality maps of Subledu Basin depicting the areas suitable or not for the irrigation as well as for drinking purposes were prepared. From these maps, it is found that groundwater from large parts of the basin is not suitable for drinking purposes while for irrigation purposes it is suitable.

Geoelectrical signatures for detecting water-bearing zones in a micro-watershed of granitic terrain from Southern India

This communication represents the application of geoelectrical signatures such as Dar-Zarrouk parameters, namely longitudinal conductance (S) and transverse resistance (T), which play a vital role in deciphering subsurface geometry and detect water-bearing zones in hard rock area. A micro-watershed is situated in granite terrain of Southern India, where the variation of bedrock depth and location of water-bearing zones are identified using these signatures, and achieved from the results of 47 Vertical Electrical Soundings (VESs) data. Pumping wells are recommended for the drilling, and the high yielded wells are confirmed in the water-bearing zones. The observed borehole lithology is very closely correlated with the interpreted geoelectric layer parameters. It indicates that the water-bearing zones exit in highly weathered zones having a resistivity range of 50–100 Ω-m, and 100–300 Ω-m in fractured granites at 12 to 22 m depths. The estimated T and S-values reveal the conductive mediums within the host granitic rock, whereas low S and comparatively high T might be indicative possible water-bearing/shear zone. The aquifer properties at the selective wells are compared to the aquifer potentiality. The high permeability values have been observed to confirm the presence of a shear zone, which is more productive for providing a good yielding bore well. Therefore, this approach could be replicated for groundwater exploration in any hard rock terrain.

Spatial pattern of groundwater recharge in Jhansi district in the Bundelkhand region, central India

Increasing demand for water has put tremendous pressure on groundwater resources in the hard rock terrain, where groundwater is a major source of agriculture, domestic and industrial purposes. Here, in the present study, we have assessed groundwater abstraction and recharge using Groundwater Resources Estimation Committee-1997 (GEC-97) norms and Water Table Fluctuation approach for the Jhansi district in the Bundelkhand region, central India. The assessment of abstraction was about 50,943 hectare meters (ham), of which ~ 91% uses for agriculture and the remaining 9% for domestic and industrial practices. We have also assessed groundwater recharge based on all available sources such as canal, rainfall, irrigation return flow, surface water structures on an annual and seasonal scale. Our results suggest higher recharge of about 42% from irrigation return flow during non-monsoon season compared to monsoon season because of higher groundwater abstraction for irrigation purposes. The rainfall recharge was about 33% in the study area during the assessment year of 2016. In general, the assessed groundwater abstraction and recharge show marked spatial and seasonal variation across the study area. The assessment of groundwater resources during 2016 suggests a ‘safe’ category of groundwater development stage for Jhansi district. The high-spatial-resolution (block-wise) assessment suggests more than 60% groundwater development stage for two blocks in the Jhansi district required better groundwater management policy. The results obtained from the present study can be helpful for high-spatial-resolution groundwater resources management.

Groundwater Potential Zone Delineation in Hard Rock Terrain for Sustainable Groundwater Development and Management in South Madhya Pradesh, India

In view of the vital significance of water resources and issues emerging from their temporal and spatial distribution and utilization posing serious problems to the land resources and to the society United Nations has identified sustainable management of water resources (SDG 6) as one of the seventeen major Sustainable Development Goals (SDGs). In this perspective, the purpose of the study is to identify the groundwater potential zones in the hard rock terrain of Betul-Chhindwara Region, Madhya Pradesh, India, using AHP technique. The study area comprises the sub-watersheds of Tawa river (Narmada basin), Tapi river (Tapi basin), Kanhan and Pench rivers (Godavari basin). Various thematic layers such as geomorphology, geology, physiography, rainfall, soil, slope, lineament, drainage density, groundwater depth, and land use/ land cover were developed. The analytical hierarchy process helps to delineate groundwater prospect zones, which are categorized into five classes, i.e. very poor, poor, moderate, good, and very good based on objective, criteria, and preference. The good, moderate, and poor groundwater potential zones cover 4815 sq. km., 6423 sq. km, and 4857 sq. km, respectively, comprising 22.46%, 29.96%, and 22.65% of the entire region under study. The result indicates that 15.22% of the area comprising 3262.10 sq. km have very good groundwater potential whereas 9.71% (2080 sq. km) has very poor groundwater potential. The obtained result has been verified through field check based on the yield data collected from 16 bore wells in the study area. The accuracy of the results was 75% that proves the efficiency of the adopted techniques. Thus, this study will be efficient for the sustainable development and management of groundwater in the study area.

Potential interplay of Uranium with geochemical variables and mineral saturation states in groundwater

Uranium (U) is formed by the interaction of groundwater in aquifer and the surrounding rocks. The area chosen for this study is a hard rock terrain of various lithology in South India, which releases U in groundwater and affect the groundwater quality. Hence, this study was conducted to understand the geochemistry and temporal variations of U in groundwater with respect to saturation state of minerals for different seasons namely Pre-monsoon (PRM), Northeast monsoon (NEM), Southwest monsoon (SWM) and Post-monsoon (POM). A total of 216 groundwater samples were collected, representing various lithology (Fissile hornblende biotite gneiss, Charnockite, Quartzite, Granite and Flood Plain Alluvium) in the study area. The collected samples were analyzed for physical parameters such as Electrical conductivity, Total dissolved solids, pH and major ions. U was measured using Laser Fluorimeter. The study infers that weathering in SWM, ion exchange in PRM and POM and anthropogenic process in NEM were the three major processes that could dominate the hydrogeochemistry of U. The higher concentration of U has been highlighted, and the water–rock interaction has been studied to know the sources of origin and it has been plotted through bivariate and ternary diagrams. The saturation index study was made and calculated for uranium, carbonate, sulfate, silicate and phosphate minerals using PHREEQC Programme. Uraninite and Coffinite are the dominant saturated states of U minerals which tend to attain near saturation to saturation state irrespective of seasons. With the increase in U concentration irrespective of seasons, it was noticed that the saturation state of minerals is also increasing. Overall, the weathering process and the lithological impact are the sources for higher concentration of U and their minerals occurring in the study area. The outcome of the study will help the policy makers for sustainable management to safeguard the groundwater resource in this region.

New methodology of simplified rock tests to determine bearing capacity in embankments and excavation bottoms

Engineering works and projects placed in rock terrains require conventional rock testing for its geological and geotechnical characterization. These tests are well-known and used in practice, but they have notable drawbacks such as high execution costs and large amounts of time required. In this research, a new methodology of simplified rock tests is presented to solve the main disadvantages of conventional rock testing and to provide useful outcomes in practical applications. The simplified rock tests proposed were developed by Professor Morilla, being a set of simple, quick, and cheap tests whose results are obtained with relative scoring systems. Furthermore, correlations with the bearing capacity in embankments and excavation bottoms have also been developed, based on the simplified rock test scores exclusively. These correlations do not include units about their magnitude, but they represent quantitative approximations about their field of application. Therefore, this new methodology is not considered as a self-sufficient design procedure for embankments and excavation bottoms. This paper covers the description of each simplified test required to obtain the bearing capacity in embankments and excavation bottoms, including the tools, steps to follow, scoring system, and the parameters and hypothesis established in the proposed correlations.

Seasonal assessment of groundwater contamination, health risk and chemometric investigation for a hard rock terrain of western India

Groundwater quality in the Shivganga river basin, Western India, was evaluated by an integrated approach using pollution index of groundwater (PIG), health risk assessment (HRA) and chemometric analysis. Sixty eight (68) representative groundwater samples were collected and analysed for pH, Electrical conductivity (EC), Total dissolved solids (TDS), major cation and anion during pre- (PRM) and post (POM)-monsoon seasons of 2016. Hydro-chemical analysis inferred that EC, total hardiness, alkalinity, boron and fluoride are exceeding the permissible limits of the World Health Organisation (WHO). PIG was computed based on considered physicochemical parameters and WHO drinking standards to ascertain the degree of pollution level. PIG results inferred that about 6% samples fall in moderate, 12% in low and 82% in insignificant pollution in PRM season; while, 12% of sample fall within low, 88% insignificant pollution in POM season. HRA was carried to know the health impacts of boron and fluoride toxicity on infants, children and adults. HRA results suggest that children are more susceptible to non carcinogenic health risk than infants and adults. Chemometric analysis included correlation matrix (CM), principal component analysis (PCA) and cluster analysis (CA) to know the relationship between water quality variables and their collective influence on overall groundwater quality. CM and PCA suggested that, inputs of TDS, Mg, NO3, Na, Cl, and SO4 are elevated due to rainfall and anthropogenic activities. These techniques are useful to evaluate the influence of seasonal variation of natural or anthropogenic processes controlling the groundwater quality in the study region.

Groundwater quality assessment using water quality index (WQI) under GIS framework

Groundwater is an important source for drinking water supply in hard rock terrain of Bundelkhand massif particularly in District Mahoba, Uttar Pradesh, India. An attempt has been made in this work to understand the suitability of groundwater for human consumption. The parameters like pH, electrical conductivity, total dissolved solids, alkalinity, total hardness, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, fluoride, nitrate, copper, manganese, silver, zinc, iron and nickel were analysed to estimate the groundwater quality. The water quality index (WQI) has been applied to categorize the water quality viz: excellent, good, poor, etc. which is quite useful to infer the quality of water to the people and policy makers in the concerned area. The WQI in the study area ranges from 4.75 to 115.93. The overall WQI in the study area indicates that the groundwater is safe and potable except few localized pockets in Charkhari and Jaitpur Blocks. The Hill-Piper Trilinear diagram reveals that the groundwater of the study area falls under Na+-Cl−, mixed Ca2+-Mg2+-Cl− and Ca2+-{text{HCO}}_{3}^{ - } types. The granite-gneiss contains orthoclase feldspar and biotite minerals which after weathering yields bicarbonate and chloride rich groundwater. The correlation matrix has been created and analysed to observe their significant impetus on the assessment of groundwater quality. The current study suggests that the groundwater of the area under deteriorated water quality needs treatment before consumption and also to be protected from the perils of geogenic/anthropogenic contamination.