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El Qaa plain is one of the promising areas for agriculture projects, owing to its soil and groundwater resources. So, 14 groundwater samples were collected, chemically analyzed, hydrochemical (ratios, models and plots) and GIS techniques were applied, to evaluate the factors governing this water chemistry and suitability for irrigation. The results indicated the expansion of the agricultural area 8 times in the last 2 decades. The water can be divided into two groups; (A) freshwater (TDS ≤ 1000) in the eastern part of the study area within the clastic weathered basement rocks part of the aquifer, and (B) saline water (TDS > 1000) in the western part within the carbonates and evaporites rich sediments and close to the Gulf of Suez. The deduced factors controlling groundwater chemistry were precipitation, evaporites dissolution, seawater intrusion and ion exchange process. The calculated sodium absorption ratio (SAR) was < 10 indicating the good quality of this water for irrigation without sodicity hazard. Water of Group (A) (electric conductivity < 2250µS/cm) can be used safely for irrigation without any impact of salinity on all types of soil and plants. Group (B) water (electric conductivity > 2250µS/cm) has salinity hazard and can be used for irrigation on well-permeable soils and salt-tolerant plants. The concentrations of the studied potentially toxic elements (PTEs) were within the permissible limit for irrigation. Expansion in agricultural activities has adverse impact on groundwater quality. So, eco-friendly fertilizers should be applied in this promising area with the application of hydrologic pumping advises to safe aquifer quality from the degradation. [ABSTRACT FROM AUTHOR]

ABSTRACT Groundwater quality assessment is crucial for ensuring safe drinking water, protecting public health, and maintaining sustainable water resources for agricultural and industrial uses. The Awash River basin faces significant groundwater quality challenges due to rapid population growth, high urbanization, large‐scale irrigation, and industrial pollution. The main objective of this study is to evaluate the intrinsic vulnerability of aquifers to pollution in the Awash Basin and identify hotspots requiring urgent intervention using a modified DRASTIC overlay analysis method. In addition to the seven parameters considered in the generic DRASTIC overlay analysis (depth to the water table, recharge, aquifer media, slope, soil media, vadose zone, and hydraulic conductivity), we incorporated land use/land‐cover (LULC) and lineament density (LD) distributions (DRASTIC‐LU‐LD). This modification allowed us to produce more realistic groundwater vulnerability maps for the basin. To identify the most influential parameters in the overlay, sensitivity analysis was conducted using Map Removal Sensitivity Analysis (MRSA) and Single Parameter Sensitivity Analysis (SPSA). Initially, the generic DRASTIC index in the area ranges from 69 to 181, categorizing the area into four vulnerability zones: very low (21%), low (51%), medium (27%), and high (1%). After incorporating LU and LD, the index values ranged from 90 to 240. Based on the percentage of the total area studied, the inclusion of LU decreased the very low and low vulnerability zones from 72% to 44% and the inclusion of LD increased the high‐ and very‐high‐vulnerability zones from 14% to 27%. The areas most vulnerable to groundwater pollution are in the western (upper Awash), middle Awash, and northwestern regions, particularly in city centers where groundwater abstraction is significant. These high‐vulnerability zones coincide with municipal, industrial, and agricultural pollution sources. The vadose zone parameter has the highest impact in both MRSA and SPSA, with a variation index value of 3.08% and a mean effective weight of 27.93%, respectively. By identifying areas vulnerable to groundwater pollution, this study provides a valuable basis for informed decision‐making and the development of effective strategies for protecting groundwater from urban, industrial, and agricultural pollution sources. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to the spatiotemporal design of groundwater quality monitoring networks for coastal aquifers. A fusion model combines the outputs of several developed simulation models to make estimates more accurate. A modified GALDIT method is used to incorporate the aquifer vulnerability to saltwater intrusion. The value of information (VOI) theory is applied to determine sufficient monitoring wells. The groundwater quality monitoring network is designed by employing a robust decision-making (RDM) approach under different management strategies and economic considerations. This approach incorporates the deep uncertainties of some critical variables, including water level and total dissolved solids (TDS) concentration at the coastline and pumping flow rates of agricultural wells. The new methodology is implemented in the coastal Qom-Kahak aquifer, Iran. The results illustrate that the combination model has significantly improved evaluation criteria compared to individual prediction models. The fusion model results indicate that thirty monitoring wells would be ideal. The RDM-based analyses in the Qom-Kahak aquifer showed that an optimal network with 30 monitoring wells outperforms the current network regarding various criteria, such as VOI and variance of estimation error. The new well configuration also demonstrates a suitable spatial distribution. Given that the current sampling frequencies are unsuitable for areas with varying vulnerabilities, we recommend sampling every 3 months in areas with moderate vulnerabilities and once every three seasons in areas with low vulnerabilities, based on the information transfer index. Finally, a management strategy in which the pumping rate should be less than 60% of the current rate is suggested to prevent saltwater intrusion into the aquifer. [ABSTRACT FROM AUTHOR]

Groundwater pollution from subsurface leaching of eroded soil, pesticides and fertilizers under agricultural fields are deteriorating the quality of groundwater. In this connection, this study aimed to prepare a groundwater vulnerability map using the DRASTIC (Depth to water table, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media and hydraulic Conductivity) model to evaluate the soil erosion and groundwater quality relationship under soil erosion prone areas of the Panjkora river basin in the northern Pakistan. In this model, relative weights between 1 and 5 are assigned (5 being the most important) to D-R-A-S-T-I-C variables that may affect groundwater quality. According to the results, 72161.64 Hectares (ha) of the study area is low vulnerable to contamination, 144828.70 ha area is slightly moderate vulnerable, 239582.22 ha area is moderate vulnerable, 121769.37 ha area is high vulnerable, and 944.61 ha area is very high vulnerable to groundwater contamination. Groundwater samples from soil erosion hotspots were examined to establish a correlation between soil erosion and groundwater contamination. Total dissolved solids (TDS) and NO2 concentration in some areas were found to be higher than the World Health Organization (WHO) permissible limits. Soil erosion exhibited a positive correlation with groundwater contamination with correlation coefficient (r) of 0.89, root mean square difference (RMSD) of 2.24 and bias of 0.094. The DRASTIC model was validated through ROC AUC curve (score = 0.62). This study is a first attempt to evaluate the inherent groundwater vulnerability and sensitivity to pollution in this region with severely declining groundwater quality due to several unexplored reasons. [ABSTRACT FROM AUTHOR]

The present study examines the water quality in the Quaternary Mio-Plio-Quaternary aquifer of the mining basin of Gafsa using a hydrochemical approach and multivariate statistical methods, to assess groundwater mineralization processes. Results from the analysis of groundwater quality collected during the winter (January 2020) and summer (June 2021) seasons reveal a pronounced stability in geochemical parameters, emphasizing a noteworthy consistency in water composition between the two seasons, with the dominance of the Na-Ca-Mg-SO4-Cl facies, in addition to the fact that all year round these concentrations are beyond their respective WHO limits. Despite the intensive extractive and transformation phosphate industry, the prolonged interaction of water with geological formations is the primary factor controlling their high mineralization. This results from the dissolution of carbonates (calcite, dolomite), gypsum, and halite. The results of the PCA represent two correlation classes. Class 1 comprises major elements sulfate, chloride, sodium, magnesium, and calcium strongly correlated with electrical conductivity (EC) and total dissolved solids (TDS). This correlation is indicative of the water mineralization process. Class 2 includes major elements nitrate and potassium weakly correlated with (TDS) and (EC) As regards heavy metals, their concentrations fall consistently below their respective potability standards established by the WHO across all water sampling points. Meanwhile, fluoride (F-) concentrations exhibited values ranging from (1.6 mg·L−1 to 2.9 mg·L−1) in the winter of January 2020 and (1 to 2.9 mg·L−1) in the summer of June 2021, surpassing its WHO limit (1.5 mg·L−1) in almost all water samples. These findings allow us to conclude that the high mineralization of these waters is acquired due to the dissolution of carbonates (calcite, dolomite), gypsum, and halite due to their prolonged interaction with the geological formations. The deterioration of groundwater quality in the Gafsa mining basin associated with phosphate extraction and processing activities appears to be primarily due to the intensive exploitation of deep-water resources. [ABSTRACT FROM AUTHOR]

To develop a specific watershed scenario, the quantity and quality of groundwater resources must be assessed and monitored locally. In the present study, an attempt has been made to identify possible groundwater potential zones, determine the quality of groundwater resources in this region, and evaluate their suitability for drinking and irrigation purposes. This goal has been achieved with the combined use of the weighted index overlay analysis (WIOA), groundwater quality index (GWQI), Remote Sensing (RS), and Geographic Information System (GIS) techniques. The proposed study area, Shanmuganadhi, is marked with superior rainfall, oscillating temperature, and runoff with litho-units encompassing charnockite (CHK) and hornblende biotite gneiss (HBG). Over-abstraction of groundwater and intensive agricultural practices have resulted in declining and degrading water quantity and quality in this area. The resulting integrated thematic map has been classified into five groundwater potential zones, namely poor, low, moderate, high, and very high, covering 3.2, 45.49, 15.3, 27.9, and 8.1% area, respectively. Sixty groundwater samples were collected during the pre-monsoon (PRM) and analyzed for major Physico-chemical parameters. From the water quality index assessment, over 28.0% of the samples fall within the “excellent,” 8.0% “good” and 4.0% “poor” in CHK, followed by 5.71% “excellent,” 48.57% “good,” 37.14% “poor,” 5.71% “very poor” and 2.87% “unsuitable” for drinking purposes in HBG terrain of this region. Irrigation indices also demonstrated that most of the groundwater samples in the CHK and HBG exposed zones exhibited good classes for irrigation purposes, as evidenced by the SAR and %Na+. The outcome, which shows the research area’s groundwater potential zones, is beneficial for improved groundwater resource planning and management. It is concluded that for larger-scale groundwater-quality investigation and assessment, the groundwater quality index-making approach (GWQI) is more practical and dependable. Water planners and decision-makers may find it helpful in effectively controlling and monitoring groundwater quality at the basin or watershed scale. Reducing urban land use and natural runoff from farms can help prevent water contamination in some regions. To ensure the safe use of groundwater, long-term monitoring of these groundwater was suggested. [ABSTRACT FROM AUTHOR]

Quantifying the flow rate distribution in a multiple‐screen recharge well is relevant to understanding groundwater flow and solute transport behavior in managed aquifer recharge (MAR) operations. In this study, an impeller flowmeter was deployed to measure flow rate distribution in a multiple‐screen MAR well under both recharge and pumping conditions screened in the multiple‐strata of the Virginia Coastal Plain aquifer system. Preferential flow distribution in the well was observed through the uppermost screens during recharge while flow distribution was more evenly distributed along all screens under pumping conditions. Analysis of flow along individual screens also indicates preferential flow to the upper part of the screen during both recharge and pumping. Comparison of flowmeter results under both recharge and pumping conditions to previous site‐specific measurements suggests that the distribution of flow may vary with time, depending on well screen condition and well rehabilitation efforts, and should be monitored over the duration of an MAR project. These results have implications for groundwater quality given that flow distribution in a multiscreen recharge well has profound impact on travel time and on transport modeling if flow is assumed to be steady and consistent under a range of operational conditions. [ABSTRACT FROM AUTHOR]

Monitoring groundwater level provides sufficient information on groundwater quantity and quality and is vital in effective management of water resources. This study applies transfer entropy coupled with directed-weighted complex network for the analysis of groundwater levels in the Sina river-basin, Maharashtra, India. All observation wells present in study area have been classified into five clusters using canopy clustering method. The direction and weight of the links of this complex network have been obtained by employing transfer entropy. Seasonal groundwater level data for pre-monsoon (May) and post-monsoon (October) were obtained from centre for groundwater board, Pune, Maharashtra for the period 1990–2009. Data analysis show that both pre-monsoon and post-monsoon groundwater level show significant decreasing trend. The proposed methodology determines the directional relationships between the selected observation wells of different clusters. It recognizes the most influenced well by using node strength and directed clustering coefficients. For each cluster, clustering coefficients and in-strength and out-strength have been calculated. Clustering coefficients for the selected wells of cluster 0 are 1, 1, 1, 0.6844 and 0.6342 which indicates Cluster 0 emerges as the strongest cluster. Similarly, clustering coefficients for cluster 4 are 0.6604, 0.6540, 0.3095, 0.2616 and 0 which means cluster 4 is the weakest among all the clusters formed. Clustering coefficients obtained for all clusters indicate that all wells within a cluster are forming clusters among themselves, however, some are strong whereas others are weak clusters. Therefore, transfer entropy can be effectively applied to groundwater and results obtained from it can be used for forecasting and water resources management. [ABSTRACT FROM AUTHOR]

Groundwater quality assessment has become vital issues all over the world as remediation of contaminated water is extremely challenging. Due to the unconfined nature of Nsukka and Igbo-Etiti groundwater and the highly intensive agricultural practices observed in these areas, assessment of groundwater vulnerability to contamination is inevitable. This study employed vertical electrical sounding (VES) in forty-two (42) different locations of Nsukka and Igbo-Etiti area with the intent to assess groundwater susceptibility to contamination using GOD, GODL and GLSI models. Results from VES delineated a total of four-to-five geoelectric layers. From VES result on the layer's geologic unit's constrained with the borehole log information on geologic unit serving as water-bearing unit in the area, the fourth layer was delineated as the aquifer layer in most locations of the study area within fine-to-medium coarse-grained sand. Results of groundwater vulnerability assessment as established using GODindex classified the aquifer units in the study area as low vulnerable units. GODLindex and GLSI models establishing different range of vulnerability index classified the areas aquifer units into high, moderate and low vulnerable zones. Results of single parameter and map removal sensitivity analysis on GOD and GODL model delineated overlying lithology and longitudinal conductance, respectively, as the most sensitive parameters in vulnerability assessment of the study area. Aquifer vulnerability potential zone maps generated revealed the vulnerability class distributions. These results will assist in sensitizing the habitants against indiscriminate disposal of waste and also guide the government in effective monitoring and management of groundwater repositories. [ABSTRACT FROM AUTHOR]

Climate change may increase the vulnerability of aquifers to contamination through extreme precipitation and extended drought periods. Therefore, the understanding of groundwater ecosystem dynamics is crucial, with bacterial assemblages playing a major role in biogeochemical cycles. The present research describes a geospatial study targeting the bacterial community structure of groundwaters from the largest karst aquifer in Portugal (the Maciço Calcário Estremenho), integrating hydrogeochemical and bacterial diversity data. A total of 22 samples were analyzed from a set of 11 geographically sparsely distributed groundwater sources in dry vs. wet seasons. The 16S rRNA gene barcoding data revealed bacterial community variability across samples in space and time. The phylum Proteobacteria was dominant across all samples (from 44 to 92% of total sequence reads), mainly represented by the classes Alphaproteobacteria (orders Sphingomonadales, BD7–3, Rhizobiales and Rhodospirillales), Betaproteobacteria (orders Burkholderiales, Rhodocyclales, Nitrosomonadales), Gammaproteobacteria (orders Pseudomonadales, Xanthomonadales, Alteromonadales, Legionellales) and Deltaproteobacteria (orders Myxococcales, Spirobacillales). Variation in the bacterial community was primarily attributed to parameters such as redox conditions (DO, ORP), Fe, Mn, SO4, PO4, Sr and Cl, but also some minor and trace elements (Al, V, Cr, Cu, Pb). Our results provide novel insights into bacterial diversity in relation to groundwater hydrogeochemistry. The strong dominance of OTUs related to bacterial taxa associated with nitrification/denitrification also highlights a potentially important role of these assemblages on nutrients (nitrogen sources) and groundwater quality dynamics at this karstic aquifer system. Moreover, the integration of bacterial assemblages information is emphasized as central for water quality monitoring programs. [ABSTRACT FROM AUTHOR]

The groundwater resources in different areas of Pakistan are heading towards depletion along with the deterioration of quality due to over-abstraction and urbanization. The main focus of this study is to map the current hydrostratigraphical and hydraulic conditions of the late Quaternary aquifers in the central part of Thal Doab of Punjab Plains. To achieve the target, a comprehensive approach was employed combining geophysical investigations using electrical resistivity surveys (ERS) and physiochemical analysis of groundwater specimens collected from the study area. Careful calibration of resistivity models was performed by comparing them with lithologs to ensure their accuracy. The current groundwater conditions were assessed through thirty vertical electrical soundings (VES) using the Schlumberger electrode configuration up to 300m of AB/2. The interpreted results revealed the presence of four to six geo-electric sublayers comprising the intermixing layers of clay, silt, sand, gravel, and kankar inclusions. These layers exhibited very low (<20 Ω-m) to very high (>230 Ω-m) resistivity zones at various depth intervals. The developed 2D/3D models of aquifer systems identify the promising areas of good/fresh quality groundwater in the regions characterized by medium to very high resistivity mainly within the sand with gravel layers. However, lower resistivity values indicate the presence of marginally suitable/fair and saline/brackish groundwater showing the existence of fine sediments such as clays/silts. Additionally, twenty groundwater samples were collected to assess various parameters including pH, TDS, arsenic, fluoride, iron, nitrate, and nitrite. The spatial distribution of these parameters was visualized using 2D maps. The suitability of the groundwater for drinking consumption was evaluated in accordance with WHO guidelines. [ABSTRACT FROM AUTHOR]

Groundwater is a precious natural element which ensures global water, food, and environmental security in the twenty-first century. Systematic monitoring, sustainable utilization, preservation and remediation are critical aspects of efficient groundwater resource management. This study deals with the analysis of spatial variability and trend in groundwater chemistry as well as identification of possible contamination sources in a coastal alluvial basin of eastern India. Pre-monsoon season data of 14 groundwater-quality variables measured in 'leaky confined' and 'confined' aquifers were analyzed for ten years (2012–2021). Mann–Kendall (M–K) test with the Sen's Slope Estimator, Spearman Rank Order Correlation (SROC) and Innovative Trend Analysis (ITA) tests were employed to assess decadal (2012–2021) trends. The analysis of the results indicated that the 'critical' water-quality parameters exceeding the acceptable limits for drinking are TDS, EC, TH, pH, Mg2+, Na+, K+, Fe2+, HCO3ˉ, Clˉ and NO3ˉ. Weak negative correlations between rainfall and groundwater elevation for both the aquifers reveal poor rainfall recharge into the aquifers. Therefore, a reduction in groundwater abstraction and augmentation of groundwater recharge is recommended. Trend analysis results indicated that the concentrations of TH, Mg2+ and Fe2+ exhibit significant increasing trends in the 'leaky confined aquifer'. In contrast, significant rising trends in TH, Mg2+, Na+, Fe2+, HCO3ˉ and NO3ˉ concentrations are identified in the 'confined aquifer'. Further, the SROC test could not detect the trends in groundwater quality in most blocks and for many parameters. On the other hand, the ITA test revealed significant trends in most of the parameters of the two aquifers in almost all the blocks. Trend magnitudes of the groundwater-quality parameters based on the Sen's Slope Estimator and the ITA test vary from –63.7 to 58.65 mg/L/year for TDS, –14 to 39.07 mg/L/year for TH, –1.49 to 4.83 mg/L/year for Mg2+, –7.14 to 22.96 mg/L/year for Na+, –0.32 to 0.44 mg/L/year for Fe2+, –8.33 to 20.75 mg/L/year for HCO3ˉ, –26.52 to 31.01 mg/L/year for Clˉ and 1.29 to 3.76 mg/L/year for NO3ˉ over the study area. The results of M–K and ITA tests were found in agreement in all the blocks for both the aquifers. Groundwater contamination in both the aquifers can be attributed to weathering, geogenic processes, mineral dissolution, seawater intrusion, poor recharge pattern and injudicious anthropogenic activities. It is strongly recommended that concerned authorities urgently formulate efficient strategies for managing groundwater quality in the 'leaky confined' and 'confined' aquifers which serve as vital sources of drinking and irrigation water supplies in the study area. [ABSTRACT FROM AUTHOR]

Free aquifers have become an important water supply option for underdeveloped and developing countries, due to the resource quality and relatively low extraction prices. However, overexploitation and the lack of territorial planning guidelines in these areas endanger groundwater availability and quality. In this context, this study aimed to analyze the vulnerability to groundwater contamination and contribute to the conservation of the ecosystem services, provided by the Guarani aquifer in Brotas, Brazil, by applying the PESTICIDE-DRASTIC-LU model. The application of this model allowed the identification of priority conservation areas within the context of ecosystem services that groundwater provides to local inhabitants. To this end, we collected, treated, and analyzed seven different hydrogeological data to understand the environmental dynamics of the system and to identify which areas are most vulnerable to aquifer contamination. The results pointed out that 64% of the study area presents zones of high and very high vulnerability to contamination, due to the local hydrogeological characteristics (sandy soils and rocks) and the various anthropogenic activities, mainly with large plantations of sugar cane and eucalyptus. In addition, the mapping allowed the spatial demonstration of the places that should be considered a priority for the conservation of ecosystem services provided by local groundwater. Thus, our results can serve as a baseline to define public action strategies for the preservation and sustainable management of the Guarani aquifer areas. [ABSTRACT FROM AUTHOR]

The present study area is an alluvial plain consisting of fine clayey sand and coarse sand with mixed lithology. In September 2018, a water sampling campaign was carried out in 28 wells spread all over the plain. The interpretation of the results from the physicochemical analysis allows determination of the hydrogeochemical behaviour and quality of the groundwater sampled in this plain. The spatial distribution of physical and chemical parameters reveals a clear demarcation between the east and the west of the study area. Water samples from wells located in the western part of the plain show a high mineralisation with high electrical conductivity and total dissolved solids. Water samples from the southern and eastern parts show intermediate to low mineralisation. Graphical representations of chemical analysis in the Piper diagrams reveal that the groundwater in the study area can be classified into five families. The evaluation of water quality shows that concentration values of some ions like Na+, Ca2+, Mg2+, Cl−, HCO3− and SO42− are generally high in the western part of the plain along the Rusizi River with very high values particularly observed in the Rusizi delta. [ABSTRACT FROM AUTHOR]

Groundwater is widely regarded as being among the freshwater natural resources with the lowest levels of contamination. Nevertheless, the saltwater intrusion has resulted in the contamination of groundwater in coastal regions with lower elevation. The rationale of the present work is to investigate the chemistry of groundwater, to identify the various facies of groundwater, to identify the processes that influence groundwater chemistry and saltwater intrusion, and to evaluate the groundwater's aptness for use in drinking and farming. In order to gain an understanding of the groundwater quality as well as the salinization process that occurs in coastal aquifers as a result of hydrogeochemical processes, a total of 108 groundwater samples (54 each in pre- and post-monsoon) were taken and analyzed for several physiochemical parameters in the southern part of the Puri district in the Indian state of Odisha. The data has undergone analysis and examination to identify the factors (such as hydrological facies, potential solute source in water, and salinization process) that contribute to groundwater salinity. The result showed the chemistry controlling processes of rock-water interaction as per Gibbs diagram. The majority of shallow aquifers exhibit the Na-Cl type of facies as per the Piper plot. A total of 37% pre-monsoon and 33% post-monsoon samples having Na+/Cl− ratio below the threshold of 0.86 indicating the influence of saltwater intrusion. In both seasons, it was observed that 74% of the samples exhibited a Na+ concentration that exceeded the permissible limit set by the World Health Organization (WHO) for drinking purposes. The findings indicate that most groundwater failed to pass safe drinking water and irrigation standards due to saltwater intrusion. Consequently, the monitoring of coastal aquifer quality has become imperative in order to ensure the sustainability of aquifers and the development of groundwater resources. This is because coastal aquifers are highly vulnerable to saltwater intrusion, primarily as a result of the extensive extraction of groundwater for diverse purposes. [ABSTRACT FROM AUTHOR]

The controlling hydrogeochemical processes of an intermontane aquifer in central Mexico were identified through multivariate statistical analysis. Hierarchical cluster (HCA) and k-means clustering analyses were applied to Na+, K+, Ca2+, Mg2+, F−, Cl−, SO42−, NO3−, HCO3−, As, pH and electrical conductivity in 40 groundwater samples collected from shallow and deep wells, where As and F− are contaminants of concern. The effectiveness of each hierarchical and k-means clustering method in explaining solute concentrations within the aquifer and the co-occurrence of arsenic and fluoride was tested by comparing two datasets containing samples from 40 and 36 wells, the former including ionic balance outliers (>10%). When tested without outliers, cluster quality improved by about 5.4% for k-means and 7.3% for HCA, suggesting that HCA is more sensitive to ionic balance outliers. Both algorithms yielded similar clustering solutions in the outlier-free dataset, aligning with the k-means solution for all 40 samples, indicating that k-means was the more robust of the two methods. k-means clustering resolved fluoride and arsenic concentrations into four clusters (K1 to K4) based on variations in Na+, Ca2+, As, and F−. Cluster K2 was a Na-HCO3 water type with high concentrations of As and F. Clusters K1, K3, and K4 exhibited a Ca-HCO3, Na-Ca-HCO3, and Ca-Na-HCO3 water types, respectively, with decreasing As and F concentrations following the order K2 > K3 > K1 > K4. The weathering of evaporites and silicates and Na-Ca ion exchange with clays were the main processes controlling groundwater geochemistry. The dissolution of felsic rocks present in the aquifer fill is a likely source of As and F−, with evaporation acting as an important concentration factor. [ABSTRACT FROM AUTHOR]

The current study was conducted to classify the quality of groundwater in wetlands. This research was carried out to evaluate the groundwater quality of wells in the surrounding area according to the Irrigation Water Quality Index (IWQI) to verify its suitability for agricultural purposes. The IWQI was developed in 2010 by Meireles; it was calculated based on the water quality parameters: EC, Na+1, Mg+2, Ca+2, Cl–1, and of 37 monitoring wells. The results of the IWQI show that the water quality declined significantly in July, with the majority of wells 76% within the severe restriction category (SR), which means that it's suitable only for irrigation of crops with high salt tolerance, and 14% of wells falling within the High Restriction category (HR). The lake's discharge decreases during the dry season, and most of the water quality classified as a severe restriction (SR), this indicates that the groundwater is influenced by the saline waters of Lake Fetzara, which are already loaded with chemical elements due to evaporation. As a result, the study of groundwater suitability for irrigation revealed that these waters are generally acceptable for irrigation of salt-tolerant crops on well-drained soils but require a prior control of salinity evolution. [ABSTRACT FROM AUTHOR]

To investigate the hydrogeochemical characteristics of shallow groundwater and evaluate groundwater salinization state in Cangzhou, China, two sampling campaigns have been conducted. In summer, 33 groundwater samples, 3 seawater samples and 5 river water samples were collected. In winter, 22 groundwater samples were collected. The hydrochemical type was determined by the Piper diagram. Evolutionmechanisms of groundwater were analyzed by the Gibbs diagram. The trend of de-salinization or salinization of groundwater was determined by the hydrochemical facies evolution diagram. The groundwater salinization grade was evaluated by both the seawater intrusion groundwater quality index (GQISWI) and the attribute recognition model based on entropy weight (ARMEW). The Piper diagram shows that Na+ is the dominant cation and Cl- is the dominant anion in shallowgroundwater, and the groundwater in this area is mainly of Cl-Na type followed by Cl-Ca·Mg type. The evaporation-crystallization process has significant influence on the evolution of saline groundwater. In summer, most brackish groundwater exhibit compositions of the freshening stage with direct cation exchange, and most saline groundwater is mainly at the seawater intrusion stage with reverse cation exchange. In winter, compared to the summer season, more groundwater samples in the middle of study area exhibit intrusion trend, and without obvious Na-HCO3 facies. In summer, values of GQISWI range from 20.47 to 75.38 with an average of 59.31. The GQISWI gradually increases from east to west, denoting the degree of groundwater salinization is alleviated from coast to inland. In winter, values of GQISWI range from 54.47 to 79.09 with an average of 66.00, slightly higher than that in summer. The proportion of no salinization (Grade I), minor salinization (Grade II) and serious salinization (Grade III) of groundwater samples in Cangzhou identified by ARMEW is 3.0%, 21.2% and 75.8% in summer, respectively. In winter, the proportion is 9.1% for Grade II and 90.9% for Grade III. The GQISWI index shows the largest area of Grade II, and ARMEW presents the largest area of Grade III in both seasons. Compared with GQISWI index, ARMEW model gives more conservative evaluation results of groundwater salinization. The results provide useful information on the groundwater salinization status for the local area, and help for the management of groundwater resources in Cangzhou. [ABSTRACT FROM AUTHOR]

A hydrogeochemical analysis was conducted to find the suitability of the groundwater for drinking and irrigation purposes in the Kuzhithuraiyar sub-basin, Kanniyakumari district, Tamil Nadu, India. 48 groundwater samples were collected from the different locations of the study area during both the pre- and postmonsoon periods. This study assesses the groundwater quality for drinking and irrigation purposes based on the analytical results, water quality index, Wilcox plot, and irrigation parameters such as electrical conductance, Kelly's ratio, sodium absorption ratio values, magnesium hazards, bicarbonate, and the residual sodium carbonate index. The pH values ranged from 8.5 to 6.5, suggesting generally acceptable conditions. TDS concentrations range from 24 to 1277 mg/L, whereas EC values range from 37.50 to 1996 μS/cm. It is observed from the collected samples that the pre-monsoon water samples TDS' values were exceeded the recommended TDS limits than postmonsoon samples. Water quality indices indicate that 50% of premonsoon samples and 48% of postmonsoon samples are suitable for drinking. In total, 10% of samples are admissible to a doubtful category before and after the monsoon, 6% are good to permissible during the monsoon, and 84% are good to permissible. Kelly's ratio shows that 56% and 48% of samples collected during the post- and premonsoon are suitable for irrigation, respectively, whereas the remaining samples are not. Due to magnesium hazards, 40% and 44% of pre- and postmonsoon samples are not suitable for irrigation. Overall, the postmonsoon samples exceeded the permissible TDS limit (1000 mg/L) by 10% and the premonsoon samples by 6. 13% of samples obtained after the monsoon and 19% collected before the monsoon have a potential salinity greater than three, indicating that these samples are unacceptable. The sustaining water quality and mitigating possible hazards in the Kuzhithuraiyar sub-basin require continuous monitoring and focused measures. [ABSTRACT FROM AUTHOR]

Maintaining soil fertility and structure in Libya requires attention to water quality and irrigation practices due to limited arable land. This study aims to assess groundwater quality in the BrackAshkada, Libya agricultural project based on physicochemical parameters such as electrical conductivity, total dissolved solids, total hardness and irrigation water quality index (IWQI), as well as some cations and anions, and irrigation indices such as sodium adsorption ratio (SAR), residual sodium carbonate, percentage sodium, permeability index, Kelly's index, potential salinity, total hardness (TH) and magnesium hazards percentage. The results indicated that IWQI is positively correlated with SAR and TH, and negatively correlated with the remaining indices. Based on the irrigation indices, the groundwater of the three wells was suitable for irrigation and can be classified as moderately water-restricted. The Piper diagram suggests that the mixed-type Ca-Mg-Cl-SO4 was dominant in the wells. The study concludes that groundwater is partially safe for agricultural use, but specific safety measures must be taken. These findings will assist farmers in enhancing soil management, crop cultivation and land sustainability. [ABSTRACT FROM AUTHOR]

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This study examined the influence of preferential flow on pore water flows and marine nitrogen transport reaction in variable saturation and variable density coastal aquifers. The 2-D unconfined aquifer model established was based on the software COMSOL by coupling the dynamic and chemical processes together. The results showed that preferential flow affects groundwater flow and salinity distribution, leading to a more complicated mixing process. The preferential flow resulted in an increase in mixing zone area and the upper saline plume area of 10.33 and 2.62m2, respectively, a decrease in saltwater wedge area of 7.22 m², and an increase in nitrate (NO3 -) removal efficiency from 7.9% to 8.97%. The NO3 - removal efficiency increases progressively with the depth (h) and quantity (n) of preferential flows; however, it decreases after a certain quantity. Further quantitative analysis revealed an increase in the intensity of nitrification and dissolved oxygen inflow flux with preferential flow depth and quantity increase. This phenomenon usually occurs on coasts where biological caves are abundant. The results also offer significant implications for designing engineering measures to mitigate saltwater intrusion and are significant to prevent groundwater quality deterioration in coastal zones. [ABSTRACT FROM AUTHOR]

Alluvial aquifers often exhibit highly conductive embedded formations that can act as preferential pathways for the transport of solutes. In this context, a detailed subsurface characterization becomes crucial for an effective monitoring of groundwater quality and early detection of contaminants. However, small-scale heterogeneities are seldom detected by traditional nondestructive investigations. Heat propagation in porous media can be a relatively inexpensive tracer for groundwater flow, potentially offering valuable information in various applications. In this study, we applied passive Fiber Optics Distributed Temperature Sensing (FO-DTS) to a group of observation wells in a highly heterogeneous phreatic aquifer to uncover structures with different hydraulic conductivity, relying on their response to temperature fluctuations triggered by natural and anthropogenic forcings. A comprehensive data analysis approach, combining statistical methods and physics-based numerical modeling, allowed for a three-dimensional characterization of the subsurface at the experimental site with unprecedentedly high resolution. [ABSTRACT FROM AUTHOR]

Iran's groundwater reservoirs have faced significant and related challenges in the past three decades. The simultaneous decrease in the volume and quality of these waters, which are increasingly contaminated with pollutants, renders them largely unusable for many uses. Therefore, there is an increasing emphasis on evaluating the quality of groundwater and identifying anthropogenic or geogenic factors that affect its quality more than ever before. In this study, the hydrogeochemical pollution caused by major, minor, and trace elements was identified by examining the water table against the electrical conductivity of water resources in Azarshahr plain. Long-term data on water levels and electrical conductivity were obtained from regional water resources in East Azerbaijan province. After initial examination, 33 samples were collected from wells and qanats in the area and transferred to the water laboratory of Tabriz University for analysis. The measured parameters included pH, electrical conductivity, major, minor, and trace elements. The results of chemical analysis showed that the concentrations exceeding the permissible drinking limit for nitrates and elements such as Arsenic, Lead, Nickel, and Chromium. Piper diagrams and Stiff diagrams were used to determine the water type in the area; it was found that the water type is mainly sulfate and bicarbonate-based. The origin of the available water is related to the geological formations in the area as a result of mixing and ion exchange. Furthermore, multivariate statistical analysis using factor analysis revealed four influential factor groups affecting water quality in the area; only the fourth factor was attributed to anthropogenic. In general, most of the trace elements in water sources are influenced by formations and aquifer-rock interactions. The overall trend of groundwater quantity over a 25-year period is relatively stable with a slight downward slope; however, the general trend of electrical conductivity is ascending with a much steeper slope indicating an increase in anthropogenic activities as well as the presence of saline layers, which leads to a decrease in the quality of groundwater. Most of the contaminated samples in terms of major and trace elements are located around Gowgan city at the end of the plain. The pollution at this end is related to dissolution trends along with movement paths of groundwater flow and density of pumping wells in this area. [ABSTRACT FROM AUTHOR]

The aquifers in the M'léta Plain are crucial for supplying drinking water and supporting industrial and agricultural water needs. However, they are facing a pollution risk and environmental degradation. The present study aims to assess the groundwater quality in the M'léta Plain, focusing on its physicochemical properties, statistics of the aquifer, pollution risks, and factors influencing the water mineralisation process. The analysis of 16 samples reveals that the water contains high levels of sulphates and chlorides, often accompanied by sodium, calcium, or magnesium. This suggests two distinct water types or facies: one characterised by sodium chloride or calcium chloride, and the other with calcic or sodic sulphate waters, sometimes including magnesium sulphate. These facies may be attributed to the influence of different formations at the outcrop. Statistical analyses reveal a strong correlation between electrical conductivity and the majority of chemical elements, indicating the impact of freshwater interacting with the underlying rock formations on mineralisation. Some results also show undersaturation of certain minerals. Furthermore, the study evaluates the water's suitability for irrigation in the M'léta Plain in accordance with Richards' classification. [ABSTRACT FROM AUTHOR]

The groundwater quality in the Lilou Coal Mine in Shandong Province can be divided into "three zones" based on the range of mining-induced fractures. Considering the observed Ordovician aquifer water level decline rate of 2.6 m/year, we propose that the saline mine water contained in Zones II and III can be injected into the well-developed underling karst Ordovician aquifer in Zone I. A water quality comparison of 27 factors demonstrated that only the Na+ concentration in the mine water exceeded that in the Ordovician aquifer water. The Ordovician aquifer has an average karst development thickness of 140 m, and the karst fracture rate ranges from 6 to 14%. The filter screen length of the injection well should reach 150 m to achieve zero pressure at the surface for an injection flow rate of 200 m3/h. With only the need to reduce Na+ concentrations below 319 mg/L, ≈ $2.4 million (U.S.) could be saved annually by simplifying the mine water treatment process. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In arid regions characterized by large variations in groundwater salinity, the data derived from irrigation and domestic water supply wells may exhibit bias, reflecting an overall lower salinity than the true aquifer distribution. This bias stems from the decommissioning, non-use, or disrepair of wells that are frequently sources of higher salinity readings, rendering them unavailable for sampling. Baseflow-fed streams, agricultural drains, seeps, springs issuing into agricultural drains, and randomly located test hole samples tend to manifest higher averages and ranges of salinity when compared to supply wells. Agricultural drain flows, springs, and test holes, if sampled following recommended guidelines, are less susceptible to such bias. This study presents a case of groundwater bias identified through an initial water well sampling program in El Paso (Texas, USA). Subsequent rounds of sampling, incorporating drain samples, spring samples, and test hole samples, revealed a more comprehensive understanding of the salinity dynamics. The dataset not only highlights the existence of bias but also provides evidence for a combined geological and agricultural origin of salinity. Additionally, it demonstrates that drain sampling in an earlier study did not accurately depict a primary salinity source due to incomplete analysis of the data. Recommendations are outlined to mitigate bias, emphasizing the importance of sample control from baseflow-fed drains, springs, water wells, and test hole samples. The study also infers the upwelling of saline groundwater from deeper formations in the study area, contributing to a more comprehensive understanding of groundwater salinity dynamics. [ABSTRACT FROM AUTHOR]

Landfill sites are subjected to long-term risks of accidental spill of leachate through the soil and consequential contamination of the groundwater. Wide areas surrounding the landfill can seriously be threatened with possible consequences to human health and the environment. Given the potential impact of different coexisting anthropic pollution sources (i.e., agriculture and cattle farming) on the same site, the perturbation of the groundwater quality may be due to multiple factors. Therefore, it is a challenging issue to correctly establish the pollution source of an aquifer where the landfill is not isolated from other anthropic land uses, especially in the case of a karstic coastal aquifer. The present study is aimed at setting in place an integrated environmental monitoring system that included microbiological, chemical, and isotope methods to evaluate potential groundwater pollution in a landfill district in the south of Italy located in Murgia karstic aquifer. Conventional (microbial plate count and physical–chemical analyses) and advanced methods (PCR-ARISA, isotope analysis of δ18O, δ2H, 3H, δ 13C, δ 15N-NO3−, and δ 18O-NO3−) were included in the study. Through data integration, it was possible to reconstruct a scenario in which agriculture and other human activities along with seawater intrusion in the karst aquifer were the main drivers of groundwater pollution at the monitored site. The microbiological, chemical, and isotope results confirmed the absence of leachate effects on groundwater quality, showing the decisive role of fertilizers as potential nitrate sources. The next goal will be to extend long-term integrated monitoring to other landfill districts, with different geological and hydrogeological characteristics and including different sources of pollution, to support the ecological restoration of landfills. [ABSTRACT FROM AUTHOR]

The assessment of hydrochemical characteristics and groundwater quality is crucial for environmental sustainability in developing economies. This study employed hydrogeochemical analysis, geospatial analysis, and groundwater quality index to assess hydrogeochemical processes and quality of groundwater in the Komadugu-Yobe basin. The pH, total dissolved solids (TDS), and electrical conductivity (EC) were assessed in situ using a handheld portable electrical conductivity meter. The concentrations of the major cations (Na+, Ca2+, Mg2+, and K+), were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). The major anions (chloride, fluoride, sulfate, and nitrate) were analyzed via ion chromatography (IC). Total alkalinity and bicarbonate were measured in situ using a HACH digital alkalinity kit by the titrimetric method. Hydrochemical results indicate some physicochemical properties of the groundwater samples exceeded the maximum permissible limits as recommended by the World Health Organization guidelines for drinking water. Gibbs diagrams indicate rock–water interaction/rock weathering processes are the dominant mechanisms influencing the groundwater chemistry. Groundwater is predominantly Ca2+-Mg2+-HCO−3 water type, constituting 59% of the groundwater samples analyzed. The groundwater quality index (GWQI) depicted 63 and 27% of the groundwater samples as excellent and good water types for drinking purposes, respectively. This study further relates the interaction between geology, hydrochemical characteristics, and groundwater quality parameters. The results are essential to inform a sustainable management strategy and protection of groundwater resources. [ABSTRACT FROM AUTHOR]

The overexploitation of coastal aquifers is one of the important reasons for the salinity of groundwater due to seawater intrusion (SWI). This study assesses the hydrochemical changes of the Ghaemshahr-Juybar (GH.-J.) plain. For this purpose, specific statistical methods, modified Piper diagram groundwater quality indicators ( GQI Piper mix and GQI Piper dom ), groundwater quality index specific to seawater intrusion ( GQI SWI ), and hydrochemical facies evolution diagram (HFE-D) along with GIS (Geographic Information System) techniques were applied to identify the spatiotemporal changes of salinity in coastal multilayer alluvial aquifer. The results show that the chemical composition in the GH.-J. aquifer is basically controlled by three main factors: (1) Caspian SWI and fossil saltwater penetration from an underlying layer, (2) reverse cation exchange process, and (3) feeding by domestic sewage, agricultural activities, and use of nitrate chemical fertilizers. The investigation of the hydrogeochemical facies evolution process shows that due to the reduction of extraction from wells, saltwater infiltration has significantly decreased. Therefore, according to the geological and lithological conditions of the aquifer and exposure to seawater, it is possible to prevent the entry of saltwater from the confined aquifer into the unconfined aquifer and the saltwater intrusion by developing well optimal operation policies in order to control withdrawal from semi-deep wells and the elimination of deep wells. This practical approach to managing the salinity of coastal aquifers is suitable for the allocating groundwater resources and for use in the development of aquifer simulation models. [ABSTRACT FROM AUTHOR]

This study explores the impact of a novel approach on the levels of SWI (saltwater intrusion) and NO3− (nitrate) contamination. Some numerical simulations were conducted utilizing a coupled model that incorporates variably saturation and density, as well as convection diffusion reaction within a sandy coastal aquifer. We verified the reliability of the model for SWI based on comparison lab experiments and for chemical reactions based on a comparison of previous in situ observations. Cutoff walls and subsurface dams cannot simultaneously control SWI and reduce NO3− contamination. A novel approach that combines subsurface dams and permeable CH2O (organic carbon) walls (PC-Wall) is proposed. Subsurface dams are utilized to prevent SWI, while PC-Walls are employed to mitigate NO3− pollution. Results demonstrate that the construction of a PC-Wall with a concentration of 1.0 mM facilitated a transition from nitrification (Ni)-dominated to denitrification (Dn)-dominated. An increase in CH2O concentration to 1.0 mM caused a significant 1942.5 % rise in mDn (the mass of NO3− removed through Dn). Increment of the distance between the PC-Wall and the ocean from 35 to 45 m could result in a 103.7 % mDn increase and reduce mN (the compound mass of NO3− remaining in the aquifer) by 11.7 %. The study offers a detailed comprehension of the intricate hydrodynamics of SWI and NO3− pollution. In addition, it provides design guidance for engineering to mitigate contamination by NO3− and controlling SWI, thus fostering the management of groundwater quality. [ABSTRACT FROM AUTHOR]

The study of groundwater quality for drinking and industrial usage is critically important for the conservation and sustainable management of groundwater resources. The main purpose of this study was to evaluate the drinking and industrial groundwater quality status of five blocks of Gurdaspur district, Punjab, India, falling along international boundary of India–Pakistan thus serving as transboundary aquifers, by investigating spatial distribution of drinking and industrial groundwater quality indices using GIS approach. To study the drinking water quality, Groundwater quality index (GWQI) method was applied. The spatial distribution map of GWQI showed that the groundwater quality was poor in the Dera Baba Nanak block as compared to the other blocks. Further, corrosion and scaling indices namely Langelier saturation index (LSI), Aggressive index (AI), Ryznar stability index (RSI), Puckorius index (PI) and Larson-Skold index (LS) were calculated with the help of water quality parameters of all the samples. LSI, AI and RSI indicated the scaling tendency of sampled groundwater while, the other two indices, PI and LS suggested the corrosive behaviour of majority of the sampled groundwater. The findings of GWQI and industrial indices indicated that the groundwater quality was by and large not suitable for drinking and industrial usage in some areas. Therefore, regular and appropriate monitoring of groundwater quality is suggested in the study area and particularly in the regions where groundwater quality issues are reported so as to sustainably manage the groundwater resources. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Nestos River delta is one of the most important and sensitive basins in Greece and Europe due to its ecosystem functions, combining intensive agricultural production with low-enthalpy geothermal energy and important ecotopes. High water quality is of paramount importance to the sustainability of the system. Systematic and continuous assessment of water quality needs to be carried out in a way that is easy and quick for decision makers and non-expert societal partners to comprehend. In this way, decisions may be made more rapidly, and involved water users may be sensitized to rational water use. To this end, this paper presents the assessment of groundwater quality in the Nestos River's western delta with the use of Poseidon (PoS), a versatile, index-based method. Groundwater samples collected from 24 and 22 wells tapping the unconfined and the confined aquifers, respectively, in four time periods (May and October 2019 and 2020) were analyzed. Using the PoS index, groundwater samples were classified according to their quality status, highlighting the parameters driving quality degradation issues, thus assisting water managers in obtaining an overview of quality status and evolution through datasets that were often large. PoS index is applied in the study area for the first time and provides a groundwater quality assessment through a unique score representative of the overall water quality status regardless of processes (anthropogenic or natural) or any kind of pressures. [ABSTRACT FROM AUTHOR]

The study deals with the hydrochemistry (EC, DO, pH, HCO3-, SO4-2, Cl-, Ca2+, Mg+, Na+, and K+) and isotopic studies (18O, 2H, and 3 H) of the groundwater of the Thal Doab, between River Indus and Jhelum, to delineate the sources of recharge and quality of groundwater. The groundwater based on isotopic data is recharged by two sources: the Indus River and rainfall shown by the depleted and enriched isotopic concentrations. The tritium concentrations revealed the short residence time of shallow groundwater as compared to the deeper groundwater. Furthermore, a deep groundwater upwelling zone has also been identified. Furthermore, it was found that the groundwater evolved in response to rock-water interaction, evaporation, precipitation, land use changes, and other anthropogenic activities. The groundwater system in the Chashma area is relatively safe for consumption. Future planning for the groundwater recharge zones should be the priority areas for protection, by the government water management and public health departments. [ABSTRACT FROM AUTHOR]

Groundwater quality degradation is a pressing concern in semi-arid coastal regions, exemplified by the Ghiss-Nekor aquifer in northeastern Morocco, spanning 100 km². This study adopts a comprehensive approach, utilizing chloro-alkaline indices, hydrochemical facies diagrams, the water quality index (WQI), and the synthetic pollution index (SPI) to assess the groundwater quality and its evolution. Key findings reveal that the Ghiss-Nekor groundwater is brackish, primarily suitable for irrigation due to high total dissolved solids (TDS). Salinization stems from reverse cation exchange, as indicated by hydrochemical analyses. WQI assessments highlight the inadequacy of this groundwater for drinking purposes, with SPI classifying 54% of wells as moderately polluted. Fine particles mitigate marine intrusion in the northwest. Overlaying land-use and electrical conductivity maps identifies the areas with poor-quality groundwater, notably near an unregulated landfill, a coastal tourist site, and a wastewater treatment facility. Ionic analysis identifies multiple saline sources, with nitrate and sulfate contributions standing out. While the study offers valuable insights, limitations include the need for ongoing data collection and source identification challenges. Nonetheless, the research underscores the urgency of effective water management, particularly around the landfill site situated above permeable deposits, offering an innovative approach with global applicability for addressing groundwater quality issues in semi-arid coastal areas. [ABSTRACT FROM AUTHOR]

This study aimed to assess the quality of groundwater for drinking and irrigation in the Pandameru River basin, Andhra Pradesh, India. Groundwater samples were collected from 46 locations within the research region during the pre-monsoon season. These samples were analyzed for various parameters such as pH, EC, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, and NO3−. The results were compared with WHO guidelines, indicating slightly alkaline groundwater. Analysis using the WQI and GIS-based interpolation provided an overall evaluation of water quality. WQI values range from 78.49 to 115.92 mg/L, indicating that 77% of the samples are safe for drinking, while 23% were unfit. Groundwater samples are found in the field of rock dominance, based on the Gibbs plot. The majority of the samples fell into the C3S1 category, which denotes water with high salinity and low sodium which is moderately suitable for irrigation purposes, according to the USSL diagram. Regarding cultivation, 78% were good, 20% doubtful, and 2% unsuitable based on the Wilcox classification. Except for a few locations, most samples were suitable for irrigation. However, some samples exceeded allowable contaminant levels due to human activity, requiring treatment before consumption. [ABSTRACT FROM AUTHOR]

Proper implementation of rainwater harvesting (RWH) fulfills long term water requirements and its effectiveness has a direct impact on groundwater recharge. This comprehensive study on effectiveness of RWH system within Chennai City, Tamil Nadu, India is done by interconnection with the aquifer, adequacy and recharging capacity into the aquifer. For this purpose, a questionnaire is formulated to collect the details of implemented RWH structures. Analysis of the responses from the individual households is carried and used to develop the spatial distributed map. The inter-connection of RWH with the aquifer shows that fully penetrated exist about 35.8%, and remaining systems needs improvement. Adequacy of RWH exist revels that major portion of RWH system (about 70.4%) are constructed with proper recharging area. The inundation criteria about 52.8% of RWH structures recharge entire rainwater to the aquifer and scope for improvement is possible in many areas. The combined spatial distribution map shows that very good condition of implemented RWH system, exist for about 1/3rd of structures, 1/4th of them are in poor state and remaining fall in good category. Hence, improvement in RWH system must be carried at several parts of the study area to enhance the groundwater quantity and quality. [ABSTRACT FROM AUTHOR]

The variation in intensity of rainfall and uncertainty in its distribution has forced us to inculcate the tapping of groundwater for agricultural purposes to such reasons, it has become critically important to analyse the quality of groundwater to determine its suitability for agricultural purpose. The current study has been carried out to demarcate the groundwater suitable zones using GIS for its usage for good agricultural practices. A total of 60 groundwater samples are collected and analysed for various parameters such as electrical conductivity (EC), pH, total dissolved solids, major cations and anions. The suitable zones for irrigation purpose and action plan for sustainable practices are suggested by computing the various irrigation water quality indices, namely, sodium adsorption ratio (SAR), sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard ratio (MHR), Kelly's ratio (KR) and permeability index (PI). The integrated method of suitability evaluation revealed that groundwater is excellent for irrigation in 2.65 km2 area of basin. It is good for irrigation in 496.88 km2 area of basin. It is permissible in an area of 677.72 km2, doubtful in an area of 438.84 km2 and unsuitable in 322.96 km2 of area. The study suggested that the advanced method of treatment such as reverse osmosis and membrane filtration is needed to treat the groundwater for irrigation and sustainable practices. [ABSTRACT FROM AUTHOR]

A common challenge in many cities in Europe is endangerment of natural resources due to soil and water pollution. Despite extensive investigation and remediation measures over decades and current practices of environmental management, residues of pollutants persist in soil and groundwater, reducing the functionality of many urban areas. In complex hydrogeological systems, where contaminated plumes are overlapping and/or diffuse contamination is present, technical and administrative activities have to be thoroughly planned and executed in the long term to secure the recovery of groundwater quality. Communities need a management strategy (MS) to manage soil and groundwater contamination in urban areas, especially where contamination exceeds local scales but does not reach the national level. A MS drives administrations to understand hydrogeological system properties, define new, reachable target values and give practical guidance for the implementation of necessary measures. Implementation of a MS fosters the early involvement of key stakeholders and their contribution to the development of MS itself. The strategy has proven to be an appropriate and flexible tool for the transfer of scientific knowledge to the planning, coordination and implementation necessary for the remediation of large-scale groundwater contamination. [ABSTRACT FROM AUTHOR]

The massive dune aquifer of Bouteldja is one of the most exploited aquifers in Algeria; as a result, its piezometric level has declined. Such pressure on the dune aquifer, in addition to its moderate-to-severe vulnerability to pollution, may lead to deterioration of groundwater quality. This study is intended to assess the quality of aquifer groundwater for drinking, irrigation and industrial purposes, and also to evaluate health risks. To this end, we analyzed data of 16 physicochemical parameters collected from 25 groundwater samples. Using the Durov diagram, principal component analysis (PCA), and Pearson's correlation matrix, we found that most major ions show similar origins related to ion exchange and the proximity of the sea. Our results showed that, overall, the groundwater intended for drinking purposes was of good or excellent quality over most the aquifer, where the majority of wells are located. However, the groundwater is mostly unsuitable for irrigation purposes according to the Kelly index (KI), percentage of sodium (Na %), magnesium hazard (MH), and irrigation water quality index (IWQI). Further, calculations of corrosivity ratios (CRs) indicated that the groundwater is unsuitable for industrial uses. Finally, a health risk assessment of iron heavy metal related to the hazard index (HI) for both ingestion and dermal exposure in children and adults showed negligible-to-low risk from iron exposure. [ABSTRACT FROM AUTHOR]

Vjosa is the main river of South Albania. Currently, the confined Quaternary gravelly aquifer in its lower course supplies drinking water for roughly 300,000 local residents. In the past years, extracted groundwater quantity has increased, whereas the groundwater quality has been affected by seawater intrusion. This paper aims to assess the groundwater quality and to discuss the dominant hydrochemical processes in the aquifer. To fulfil this goal, the study discusses the groundwater quality's spatial and temporal variations on the basis of the hydrochemical parameters and ratios for 2010–2021 period, during which data are collected from three monitoring wells, located 6, 14 and 17 km, from the sea. While for 1961–2009 period, hydro-chemical water types and TDS maps are prepared using roughly 100 chemical analyses. The hydro-chemical parameters are discussed related to the factors controlling the groundwater's chemical constituents and the groundwater extraction. Heavy metals and nitrates' contents indicate that the aquifer is not affected by anthropogenic pollution. The main conclusion is that the groundwater quality is affected by seawater intrusion due to overexploitation. The study reveals its gaps, mentions its possible usefulness, and underlines the discrepancy between the policy makers and the hydrogeologists approaches concerning groundwater extraction. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A geophysical resistivity survey was conducted in Zehri tehsil in the district of Khuzdar for the metering of subsurface hydrogeological properties of aquifers. The Schlumberger electrode arrangement was employed with the vertical electrical sounding (VES) method for subsurface exploration. Two profile lines were designated for the survey. The distance between the two profile lines was about 1500 m and each profile contained four VES stations. The results of profile one show the aquifers were encountered in fractured limestone of the Jamburo Formation of Paleocene age at an average depth of 127 m, with an average resistivity of 39.7 Ωm, and the average aquifer thickness was 54.025 m. The result of profile two shows the aquifers were encountered only in VES four in the sandstone lithology of the Ziddi Formation with a resistivity of 79.9 Ωm, at a depth of 120 m with, and a thickness of 40 m. There was no aquifer encountered in the remaining all VES. The main lithology of these VES is thick impervious compacted limestone, shale, and clay of Jurassic age from the Ziddi Formation. The current tube wells were also rapidly depleting in the study area. The main factor behind the decline of aquifers in the study area is an uncontrolled installation of tube wells and continuous pumping of tube wells for agricultural purposes badly puts stress on aquifers and directly deteriorates the quality and quantity of groundwater. [ABSTRACT FROM AUTHOR]

This study utilized geographic information system-based overlay and index methods (DRASTIC, DRASTIC-LU, GOD and AVI models) in mapping groundwater vulnerability zones in Ondo town, Southwestern Nigeria. The models' parameters were based on hydrogeological (well/borehole) data, geophysical data, and satellite imageries. The weightage of different parameters was done using analytical hierarchy process. The AVI distinguished the area's vulnerability into two zones as high (94%) and extremely high (6%); GOD distinctly categorized the area into four vulnerability zones, comprising low (42%), moderate (17%), high (25%) and very high representing 16% of the study area. The AVI and GOD showed 60% correlation. On the other hand, the DRASTIC model showed three major zones, as moderately high found in the northwestern part, high, and very high vulnerability zones, constituting 33%, 50%, and 17%, respectively. The DRASTIC-LU based on index values, divided the area into high vulnerability zone (100–120) constituting 87% and very high vulnerability zone (120–145) with 13% aerial coverage. Thus, there is high level of correlation among the models (about 60%), as all displayed high/very high vulnerability zones which characterized the southern part of the study, which was also validated by the nitrate map with nitrate concentration varying from 7 to 15 mg/L. Thus, land use/cover, slope, hydraulic conductivity, net recharge, soil media, and depth to water level are very influential on groundwater quality in the study area, but land use/cover is the most predominant factor. The high percentage of the high vulnerable areas in the south requires prompt action to safeguard the aquifers from further pollution risk. [ABSTRACT FROM AUTHOR]

The primary aims of this research paper involve the creation and verification of machine learning-based quality models that utilize Integrated Irrigation Water Quality Indices (IIGWQIs) through an integrated GIS approach. We utilize the Least-Squares Support Vector Machines (LS-SVM) and the Pearson Correlation Fuzzy Inference-based System (PC-FIS) to establish forecasts for groundwater quality in the Meknassy basin. This basin serves as a representative case of an irrigated region in a mining environment under arid climatic conditions in central Tunisia. The evaluated factors for groundwater quality encompass the Irrigation Water Quality Index (IWQIndex), Sodium Adsorption Ratio Index (SARIndex), Soluble Sodium Percentage Index (SSPIndex), Potential Salinity Index (PSIndex), Kelley Index (KIndex), and Residual Sodium Carbonate Index (RSCIndex). These factors were determined based on measurements from 53 groundwater wells, which included various physico-chemical parameters. The hydrogeochemical facies identified included Ca-Mg-SO4, mixed Ca-Mg-Cl-SO4, and Na-Cl facies, revealing processes such as carbonate weathering, carbonate dissolution, interactions between rocks and groundwater, and mixing ionic substitution. In terms of the irrigation suitability categories, the IWQIndex, SSPIndex, PSIndex, Kindex, and RSCIndex indicated no limitation or minimal limitation (77.36%), secure (92.45%), favorable to excellent (66.04%), favorable (81.13%), and average to secure (88.68%), respectively. However, only 15.09% were considered favorable, according to SARIndex. The evaluation of the predictive models revealed the effectiveness of both the PC-FIS model and the LS-SVM model in accurately forecasting the IIGWQIs. [ABSTRACT FROM AUTHOR]

The hydrogeochemical profile of groundwater in the southern Kerala coast - Arattupuzha, in Alappuzha, Kerala, India is reported for drinking and domestic suitability. People at Arattupuzha mostly depend on public water supply for their domestic and drinking requirements due to limited freshwater availability. In this context, the palatability of coastal groundwater sources was evaluated and presented based on the weighted arithmetic mean Water Quality Index (WQI) and Pollution Index of Groundwater (PIG) methods. Groundwater was collected from 6 shallow (Dug wells) and 5 deep (Bore wells) sources during pre-monsoon (PRM), monsoon (MON) and post-monsoon (POM) seasons in 2019. Water was analysed for various physical and chemical parameters viz. pH, Eh, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Alkalinity (TA), Total Hardness (TH), Cl-, SO4 2-, HCO3 -, total iron, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), NO3 -, Na+, K+, Ca2+ and Mg2+. The results were compared with the WHO and BIS standards for drinking water quality. The WQI showed that most of the groundwater sources are unsuitable (WQI > 100) for direct drinking purposes. This is attributed to the total iron, TH and TA; hence, it requires pre-treatment prior to use. In the PRM season, the WQI values were 74.5±95.5 (Shallow Groundwater - SG) and 315.1±151.4 (Deep Groundwater - DG), indicating poor water quality, while in MON and POM, these were 181.9±125.4 (SG), 413.8±296.7 (DG) and 225.2±97.9 (SG), 406.4±132.6 (DG), respectively showing non-suitability for drinking purpose. Hill-Piper Trilinear diagram revealed Ca-Mg-HCO3 as the dominant hydrochemical facies. PIG results revealed insignificant pollution (PIG < 1) in water with 0.5±0.3 (SG) and 0.6±0.3 (DG) values in PRM. Additionally, the Durov, Stiff and radial diagrams were used to represent the prominent ionic composition of water sources. Overall, the groundwater quality of Arattupuzha coastal area revealed that groundwater in pre-monsoon was much safer than in the monsoon and post-monsoon seasons. [ABSTRACT FROM AUTHOR]