Groundwater Sources Research Articles

Assessment of the Effects of Human Settlements on Quality of Ground Water Sources in Lamu Island, Kenya

Assessment of the Effects of Human Settlements on Quality of Ground Water Sources in Lamu Island, Kenya

Factors affecting iron and manganese dissolution in groundwater: treatments with simultaneous oxidation and precipitation methods

ABSTRACT This study explores variations in groundwater (GW) pH, conductivity, ammonium, iron, and manganese parameters to reveal prospective interactions having an impact on the dissolved metal concentrations. To this end, bivariate and partial correlation procedures were applied to the data to obtain incisive evaluation. Besides characterisation efforts, photocatalytic iron and manganese removal experiments were also carried out with Ni-doped TiO2 nano-composite thin films (TFs) on real GW samples. UV-A (365 nm) An LED array was used as the illumination source. The experimental setup was based on three treatment routes including photocatalytic oxidation (PCO), NaOH-aided precipitation and PCO with simultaneous precipitation (SPCO-P). The main statistical analysis and treatment efforts have been performed on data and samples of a single well, respectively (N = 15). However, extended statistical analysis has also been performed on larger data groups (N = 1366) obtained from different GW sources as well. Analytical results have revealed that about 90% of iron and manganese were in oxidised forms which do not precipitate by simple pH regulation. Statistical analysis has also revealed significant interactions between metal concentrations and observed parameters depending on the level of pH and conductivity. Furthermore, the SPCO-P strategy has provided a four-fold increase in reaction rate (pseudo-first-order, kobs: 0.04 min−1). Removal efficiencies of iron and manganese also increased from 10% to 96% – 85%, respectively.

Comparative Assessment of Ground and Surface Water Sources from Awo Mmama Community, Imo State, Nigeria

Comparative Assessment of Ground and Surface Water Sources from Awo Mmama Community, Imo State, Nigeria

Revealing nitrate sources seasonal difference between groundwater and surface water in China's largest fresh water lake (Poyang Lake): Insights from sources proportion, dynamic evolution and driving forces.

Tracing the source of nitrate is the key path to solve the problem of nitrogen pollution. However, the seasonal difference of nitrate sources in groundwater and surface water and its dynamic evolution process and mechanism in large fresh water lake area are still not clear. In this study, 126 water samples were collected from groundwater and surface water in China's largest fresh water lake (Poyang Lake) region from 2022 to 2023. Bayesian stable isotope mixing model, absolute principal component score-multiple linear regression, ion ratio coefficients and uncertainty index (UI90) were used to investigate the nitrate sources variation in groundwater and surface water as well as its uncertainty in Poyang Lake area. Results showed that anthropogenic influence had significant influence on nitrate sources, which was mainly affected by chemical fertilizer (CF), soil nitrogen (SN) and manure and sewage input (M&S). Specifically, from 2022 to 2023, CF contributed 16.6% to 32.4%, SN contributed 26.0% to 38.1%, M&S contributed 26.5% to 48.2% to groundwater. CF contributed 38.8% to 43.9%, SN contributed 37.6% to 40.6%, M&S contributed 12.3% to 18.6% to surface water. The sources and proportion of nitrate in groundwater and surface water exhibited obvious difference. Temporal heterogeneity, land use type, population density and vegetation cover type had influence on nitrate sources. UI90 results showed that there was uncertainty in nitrate sources tracing process, with SN (mean 0.78), CF (mean 0.64), M&S (mean 0.35) and AD (mean 0.09), respectively. These results will provide vital references for understanding nitrate sources variation, controlling and removing nitrate surplus in groundwater-surface water system in the similar large fresh water lake areas.

Comprehensive analysis of naturally occurring radionuclides in well water: Isotopic ratios, mitigation, and dose assessment.

In Sweden, around 20 % of the potable water comes from groundwater sources and about one million people drink water from their private wells. In areas with moderate or high abundance of naturally occurring radionuclides in the bedrock, the groundwater could be enhanced with radio and chemically toxic elements such as uranium, radium, lead and polonium. Therefore, this study aims to carry out a comprehensive analysis of the behaviour and radiological impact of naturally occurring radionuclides in well water. For that, a well water survey was done in 2020 along Sweden, focusing the study on the determination of 210Po, 210Pb, 226Ra, 228Ra, 238U and 234U by alpha spectrometry. The results of the present study showed that the naturally occurring radionuclides distributions in the well water investigated were highly variable. In addition, the radionuclides with the highest contribution to the indicative dose were 210Pb > 228Ra > 210Po > 226Ra > 234U > 238U. On the other hand, the filtration and aeration purification treatment could help to remediate the radiological impact. However, the dose assessment results point out the need to include well water in the framework of the current regulations of requirements for the protection of the health of the public regarding radioactive substances in water intended for human consumption, to guarantee the quality of water from the radiological point of view.

Geogenic sources and high fluctuation rate of groundwater table accelerate the high fluoride in the aquifer of Manbhum-Singhbhum plateau fringe (India)

Fluorosis endemic is a foremost issue in the ancient Manbhum Singhbhum Plateau Fringe of India. Thus, the principal objectives of this study are i) to investigate the spatiotemporal distribution of fluoride contamination over the extended section of the Manbhum-Singhbhum Plateau and ii) to examine the fluctuation rate of groundwater, the geogenic sources of fluoride and their degree of impact. About 954 samples were collected from groundwater sources and tested using the Spectrophotometer. The Schmidt-Hammer (SH) method has been applied to identify the degree of weathering. Groundwater table fluctuation (GWTF) has been assessed using the Innovative Trend Analysis (ITA). The maximum concentration of fluoride was 19.3 mg/L in groundwater and 12.4 mg/kg in fluorite and apatite minerals. Areas with a negative trend of GWTF is faced high fluoride (>2.5 mg/L). Fluoride is high (>2 mg/L) where the SH values are less than 25. The outcome will be helpful for groundwater resource management.

Spatiotemporal variability of groundwater chemistry, source identification and health risks in the southern Chinese Loess Plateau

Groundwater pollution of the loess plateau regions has become a global concern due to its vulnerability to natural and anthropogenic influences. In this study, 146 water samples were investigated to identify the spatiotemporal variability in groundwater chemistry, pollution sources and nitrate health risks in two interconnected river basins of a typical loess region. The results showed that except for bicarbonate, spatiotemporal variability of hydrochemical components in Malian River Basin (ML) was generally greater than that in Upper Jinghe River basin (JH-U) due to the hydrogeological conditions, and the hydrochemical facies in two river basins transformed from SO4·Cl and Cl·SO4 types to HCO3 and HCO3·SO4 types. The results of integrated-weight quality index (IWQI) showed that 77.8 % (1970s), 33.3 % (2004), 34.3 % (2015) of samples in ML exceeded the standard limits of Class IV groundwater quality, displaying a high pollution level with an improvement trend, while groundwater quality in JH-U indicated a very low pollution level with a deterioration trend. The geogenic source was identified as a main factor affecting groundwater quality, with contributions of 59.2 % and 48.7 % in JH-U and ML (2015), respectively. The anthropogenic sources including agricultural activities (20.7 % and 21.8 % in JH-U and ML) and coal mining activities (20.1 % and 29.5 % in JH-U and ML) also played a role in affecting groundwater quality. The nitrate health risk assessment demonstrated that 39.1 % and 20.3 % of groundwater samples (2015) significantly exceeded the standard threshold (Hazard Index = 1), implying a higher health risk to children than adults, and the nitrate health risk in ML was obviously greater than that in JH-U. This study provides novel insight into the spatiotemporal variability in groundwater chemistry, quality and health risk in loess regions under the influence of geogenic and anthropogenic factors.

Modelling PFAS Transport in Lake Ekoln: Implications for Drinking Water Safety in the Stockholm Region.

Per- and polyfluoroalkyl substances (PFAS) are found frequently in both groundwater and surface water sources across Sweden posing challenges to drinking water supply. Lake Ekoln is located south of Uppsala and is the basin of Lake Mälaren; Lake Mälaren is the third largest lake in Sweden and is the drinking water source for more than two million people. The aim of this study was to simulate the fate and transport of PFAS in Lake Ekoln during the period 2017 - 2020 using three-dimensional hydrodynamic modelling. The simulated water temperatures were in agreement with the observed water temperatures. The simulated PFAS concentrations were generally in agreement with the available measurements, but the lack of measurements made the comparison uncertain. The modelling results described the seasonal variations of PFAS in Lake Ekoln informing the operation of the drinking water treatment plants located downstream. The modelling results confirmed that the main inflow to the lake - the river Fyrisån - is the main source of PFAS to Lake Ekoln, highlighting the importance of mitigating this source in the context of ensuring safe drinking water supply in the Stockholm region. Regular monitoring of PFAS in the river Fyrisån is needed, and additional measurements in Lake Ekoln would facilitate further model development.

Insight into Iron(III)-Tannate Biosorbent for Adsorption Desalination and Tertiary Treatment of Water Resources.

An innovative biosorbent-based water remediation unit could reduce the demand for freshwater while protecting the surface and groundwater sources by using saline water resources, such as brine, brackish water, and seawater for irrigation. Herein, for the first time, we introduce a simple, rapid, and cost-effective iron(III)-tannate biosorbent-based technology, which functions as a stand-alone fixed-bed filter system for the treatment of salinity, heavy-metal contaminants, and pathogens present in a variety of water resources. Our approach presents a streamlined, cost-efficient, energy-saving, and sustainable avenue for water treatment, distinct from current adsorption desalination or conventional membrane techniques supplemented with chemical and UV treatments for disinfection. The proof of feasibility for effective treatment of heavy metals, adsorption desalination, and cleansing of pathogens is demonstrated using synthetic water, brine, and field-collected seawater. The adsorption equilibrium and adsorption kinetic isotherm models, and mass transfer diffusion models confirmed the sorbent's function for sieving heavy-metal ions-silver (Ag+), cadmium (Cd2+), and lead (Pb2+)-from water. The maximum adsorption capacities (q m) of the sorbent for Ag+, Cd2+, and Pb2+ reach 96.25, 66.54, and 133.83 mg/g at neutral pH. The sorbent's affinity for heavy-metal-ion adsorption significantly increased, yielding q m of 116.57 mg/g for Ag+, 104.04 mg/g for Cd2+, and 165.66 mg/g for Pb2+, at pH 9, respectively, due to the sorbent's amphoteric nature. The pristine sorbents exhibit exceptional adsorption desalination efficacy (>70%) for removing salinity from brine and seawater, promoting heterogeneous adsorption. Fe(III)-TA's ability to disinfect seawater, with 67% efficacy over a very short contact time (∼15 min), confirms its remarkable antimicrobial properties for contact active mode pathogens cleansing. By preventing the release of salts, heavy-metal contaminants, and pathogens into the environment, our results proved that this novel multiplex biobased sorbent approach directly contributes to the water quality of surface and groundwater resources.

Hydrogeochemistry, Water Quality, and Health Risk Analysis of Phreatic Groundwater in the Urban Area of Yibin City, Southwestern China

With rapid urbanization, intensified agricultural activities, and industrialization, groundwater resources are increasingly threatened by pollution. Industrial wastewater discharge and the extensive use of agricultural fertilizers in particular, have had substantial impacts on groundwater quality. This study examines 18 groundwater samples collected from the main urban area of Yibin City to assess hydrochemical characteristics, spatial distribution, source attribution, water quality, and human health risks. Statistical analysis reveals significant exceedances in TDS, NO3−, Mn, and As levels in groundwater, with elevated concentrations of B as well. Isotopic analysis identifies atmospheric rainfall as the primary recharge source for groundwater in the area, with water–rock interactions and limestone dissolution playing key roles in shaping its chemical composition. Applying the Entropy-Weighted Water Quality Index (EWQI) for a comprehensive water quality assessment, the study found that 94.44% of groundwater samples were rated as “good”, indicating relatively high overall water quality. Deterministic health risk assessments indicate that 72.22% of the groundwater samples have non-carcinogenic health risks below the threshold of 1, while 66.67% have carcinogenic health risks below 1.00 × 10−4. Monte Carlo simulations produced similar results, reinforcing the reliability of the health risk assessment. Although the study area’s groundwater quality is generally good, a significant human health risk persists, underscoring the need to ensure the safety of drinking and household water for local residents. This study provides a valuable reference for the rational management and remediation of groundwater resources.

Surveillance of Vibrio cholerae serogroups (O1 and O139) from surface and ground water sources in the Vhembe district, Limpopo province, South Africa

IntroductionVibrio cholera is increasingly emerging as a significant public health concern in developing countries. Choleragenic Vibrio cholerae O1 and O139 has reported to cause devastating disease and economic burdens in developing countries. In rural areas of the Vhembe district, most rivers and several communal boreholes are polluted as a result of sanitation issues around these water sources. The aim of this study was to determine the presence of choleragenic V. cholerae O1 and O139 in rivers and communal boreholes.MethodsThe analysis of physicochemical parameters and molecular techniques was used to establish the adaptation and detect the serogroups of V. cholerae in the water samples.Results and DiscussionThe results reported that electrical conductivities (EC) ranged between 18.78 and 154 μS/cm, with rivers such as Madandze and Mvudi recording >80 μS/cm, and those of the communal boreholes were ranged between 23.4 and 295 μS/cm, which were above the acceptable South African water quality guidelines of 0–70 μS/cm for rivers and communal boreholes. The results further revealed that most of the rivers detected positive for V. cholerae, except for the Mukhase river; the downstream points of Livuvhu and Nwedi rivers and the upstream point of the Nzhelele river; and several of the communal boreholes (Mak B1, B2, Kwe B3, 4, and 6) also tested positive for the presence of V. cholerae. The toxigenic Vibrios was also reported in Mutshundudi, Tshinane rivers, the upstream of Dzindi, Madanzhe, Nwedi, and the downstream of Sambandou rivers, as well as Mak B1, B2, and Kwe3 of communal boreholes. The serogroup O1 was detected on the Mutshundudi and Tshinane rivers, while serogroup O139 was detected upstream of the Dzindi, Madanzhe, Mutshundudi, and Tshinane rivers. There was also detection of the O1 serogroup in the communal boreholes (Mak B1 and Kwe B3), while O139 was only detected in one communal borehole (Mak B2). The development of robust policies, including an integrated water and sanitation safety surveillance web tool for monitoring water resources and public health protection, is required to make sure that drinking water in rural communities is safe for consumption.

Study of Seasonal Variability of Ground Water Quality in Sarguja District (C.G.), India

Water is the vital essence, miracle of nature and the great sustainer of life. It is extremely essential for survival of all living organism. Ground water serves as a major source for drinking, irrigation and industrial purpose all over the world. Many factors affect the quality of groundwater and cause major health issues. Therefore regular monitoring of ground water quality is necessary. Present paper has formulated on the basis of assessment of impact of geological features and agricultural runoff in ground water sources of Sarguja district (C.G.) India. Water samples were collected from ten environmentally significant spots for analysis of physical, minerals, nutrients, agricultural qualities and toxic metallic and non metallic elements. The procured experimental values were subjected for the statistical evaluation and compared with the standard values prescribed by the water monitoring agencies BIS (2012) and WHO (2011). The result for pH recorded up to 10.0, turbidity (15.67 NTU), TS (720 mg/L), F- (15.67 mg/L), Fe (2.366 mg/L), Na (115 mg/L), in maximum concentration. The statistical parameter such as mean, standard deviation, standard error, % CV, correlation matrix and water quality index (WQI) were systematically calculated for pre monsoon, monsoon and post monsoon session. The obtained results are far away from the standard values which showed the investigated water samples are not suitable for drinking and agricultural purpose without prior treatment.

Preliminary Analysis of the Chemical Characteristics and Boron Sources of Surface Water and Groundwater in the Cherchen River Basin of Xinjiang

The climate of the Cherchen River Basin （CRB） is dry and rainless and the water resources are relatively scarce. Identifying the chemical characteristics and high boron sources of surface water and groundwater in the basin is important for the sustainable development and utilization of water resources and the protection of animals, plants, and human health. To preliminarily explore the chemical characteristics and the main sources of boron （B） in the CRB, a total of 46 groups of water samples （including six groups of river water and 40 groups of well water） were collected in 2023. The chemical characteristics of surface water and groundwater and the sources of boron in the CRB were preliminarily analyzed using a Piper diagram, Gibbs chart, correlation analysis, hydrogeochemical simulation, and absolute principal component analysis （PCA-APCS-MLR） and the contribution of different factors to boron and other chemical components was quantitatively evaluated. The results showed that the water resources in the CRB were weakly alkaline, with an average pH of 7.99. The groundwater was mostly brackish water and salt water and the anions and cations were mainly Cl- and Na+. Many types of water chemistry were present, among which the river water was mainly SO4·Cl-Na type and HCO3·SO4·Cl-Na type. The groundwater was mainly SO4·Cl-Na type. The average content of boron in river water in the area was 1.80 mg·L-1 and the over standard rate was 66.7%. The average content of boron in groundwater was 1.48 mg·L-1 and the exceeding standard rate was 45.0%. APCS-MLR receptor model analysis further revealed that the major sources of water chemical components and boron were leaching-enrichment, anthropogenic activity, and primary geological factors and unknown sources. The phenomenon of boron exceeding the standard in the water of the Cherchen River Basin was obvious, mainly due to agricultural activities （fertilizers and pesticides） and unknown sources. Isotope technology may further identify the main sources of boron in water.

Hydrogeochemical characteristics, source distribution, and health risk of high-fluoride groundwater in Swabi, Pakistan.

This paper evaluated fluoride (F-) pollution in drinking groundwater sources, which causes severe fluorosis and other human health concerns in Swabi, Pakistan. We determined F- concentration, prevalence, enrichment, distribution, and health hazards from water ingestion in Swabi, Pakistan. Therefore, 126 groundwater and 18 surface water samples were collected to analyze F- and other geochemical tracers to understand groundwater enrichment and F- mobilization in aquatic systems. The range and mean values of F- in groundwater were 0.02 to 14.2 and 4.0mg/L, and those in surface water were 1.12-0.8 and 1.4mg/L. Most residents used groundwater for drinking purposes. Thus, groundwater results showed that 72.2% of samples had surpassed the WHO guidelines of F- 1.5mg/L. The fluoride pollution index (FPI) declared that 48.73% of samples showed a higher risk, 41.95% medium risk, and 9.32% lower risk. Mineral phases using PHREEQC interactive software determined mineral saturation revealing the dissolution of host rock minerals and unsaturation showed precipitation of minerals within the aquifer. The principal component analysis multilinear regression (PCA-MLR) model showed a five-factor solution: (a) geogenic processes, (b) mixed geogenic and anthropogenic inputs, (c) geochemical processes, (d) agriculture pollution, and (e) industrial effluents which would release F- in the aquifer. The health hazard due to higher F- revealed that children showed high-risk levels compared to adults in endemic areas. The spatial distribution of F- in drinking groundwater increases towards the northern side and decreases in the south to the southeastern side. Therefore, effective water management techniques would be required to safeguard groundwater resources and secure human health from dental and skeletal fluorosis and other associated problems caused by high F- groundwater with varying fluoride concentrations. This study will help the water management authority to safeguard depleted groundwater for drinking demands.

Tracing Groundwater‐Surface Water Interactions in a Volcanic Maar Lake Using Stable Isotopes and 222Rn

AbstractIsotope hydrological studies to understand groundwater‐surface water interactions in tropical, high‐elevation catchments are limited. These interactions are important in controlling lake water residence time, aqueous biogeochemistry, and water availability for downstream communities and ecosystems. To better comprehend the complexity of spatio‐temporal variations in the aquifer‐lake domain in tropical volcanic regions, a multi‐tracer approach including water and inorganic carbon stable isotopes (δ2H, δ18O, δ13CDIC), hydrochemistry, and 222Rn was applied in Lake Hule, northern Costa Rica. Seasonal isotope mass balance calculations using lake, stream, precipitation, and groundwater compositions were supplemented with local hydrometeorological information. Evaporation to inflow ratios (E/I) revealed a small variability between the dry (December–April) and wet seasons (May–November), with relatively low evaporation losses, 2.9 ± 1.0 % and 3.2 ± 1.8 %, respectively. Bayesian end‐member analysis indicated that annual inputs from groundwater, precipitation, and runoff represented 61.3 ± 8.1%, 24.4 ± 8.4, and 14.3 ± 5.9% of total lake inflow, respectively. Temporal variations of δ13CDIC confirmed the key role volcanic carbonate buffering plays in this lake and indicated greater CO2 degassing from groundwater sources in the wet season. This tracer‐aided assessment in a volcanic lake maar of northern Costa Rica provides evidence of previously unknown groundwater‐surface water interactions and illustrates the application of isotopic tools for estimating water balances and seasonal variability of groundwater discharge into natural lakes across the volcanic front of Central America.

Reliability analysis of rainwater harvesting system for crop water supply in greenhouse

Abstract Climate change has an impact on the scarcity of sustainable water sources for plant water supply in a greenhouse. In the dry season, the availability of groundwater and surface water sources is insufficient to supply the crop water requirements. Adequate and consistent water supply is crucial to support the optimal growth and production of plants in a greenhouse. Rainwater harvesting can be an important alternative to mitigate water scarcity, reduce groundwater exploitation, and preserve environmental sustainability. This study investigates the reliability of rainwater harvesting from greenhouse roofs to supply the water demands of vegetable crops cultivated in the greenhouse surface area. The analysis was conducted based on rainfall depth values of a 20-year time series (2004-2023) from a representative rainfall station of the study area. The rainwater harvesting in the greenhouse can produce a capture volume of 25.43 m3 (227.02 L/m2) with a cumulative capture volume of 2116.72 m3 and 20.07 m3 (179.19 L/m2) with a cumulative capture volume of 1643.82 m3, represents a mean monthly rainfall of 283.78 mm and a dependable rainfall with an 80% probability of 223.98 mm, respectively. The reliability of the rainwater harvesting system can fully supply the water needs of the vegetables-cucumber family, small vegetables, roots and tubers, and vegetables-solanum family, reaching 2.81 L/m2.day, 2.95 L/m2.day, 3.09 L/m2.day, and 3.23 L/m2.day, respectively. The average surplus of 18.91 m3 was produced in the design based on the mean monthly rainfall depth and 13.55 m3 in the dependable rainfall depth of 80% probability.

Physico-chemical properties and the stable isotope composition of groundwater in Mandalika and its surrounding, West Nusa Tenggara, Indonesia

Abstract Groundwater is a very important source of clean water in coastal areas such as the Mandalika area, Central Lombok Regency, and its surroundings. The Mandalika area is one of the special economic zones in Indonesia, and it is a world-class tourist destination. However, in terms of hydrogeology conditions, Mandalika is located in a poorly productive aquifer area. Therefore, it is necessary to identify the quality and existence of groundwater. The objective of this study is to assess the viability of groundwater as a source of clean water by analyzing its physico-chemical properties. Additionally, the study intends to pinpoint the origin of groundwater sources by examining stable isotopes of hydrogen (δ2H) and oxygen (δ18O). In order to achieve the objectives, a campaign of water sampling was conducted on several springs, drill wells, and also rainwater at different elevations. As a result, the range of physico-chemical characteristics of groundwater found with temperature values 30.60 °C-31.80 °C, pH 6.50-7.11, Total dissolved solids (TDS) 393.00 mg/L-1,384.00 mg/L, and Electric Conductivity (EC) of 789.00 μS/cm-2,780.00 μS/cm. Most of the groundwater samples collected met the drinking water criteria. According to isotope data, all groundwater samples are estimated to come from meteoric water and originated from a recharge area, which is located at an elevation of 15-285 masl. Based on these results. It can be concluded that groundwater is actually a potential source of clean water supply in this area, and research on the potential of groundwater quantity is urgently needed.

Assessing inter-basin groundwater input to the Verlorenvlei estuarine lake using stable isotopes and hydrochemistry

Study region: Verlorenvlei Catchment (∼1 890 km2) is an agriculture-dominated area (∼43 % per km2) on South Africa’s west coast. This semi-arid region has variable rainfall and high evaporation rates, affecting the three major aquifers and Verlorenvlei – a RAMSAR-listed estuarine lake. Study focus: Natural processes (i.e., extended dry periods and evaporation) and anthropogenic activities (i.e., agricultural expansion and groundwater abstraction) have threatened Verlorenvlei’s ecological functions. Seasonal and spatial changes between the water sources (i.e., direct rainfall, surface water, and groundwater) supporting Verlorenvlei were determined using δ18O and δ2H isotopes and hydrochemical analyses. Inter-basin aquifer contribution was investigated to assist in explaining Verlorenvlei's slow recovery since the recent 2015 – 2018 Western Cape drought. New insights: A proportion of groundwater from outside the topographic and surface-water delineated catchment supports Verlorenvlei during the dry month of April (i.e., G30F Langvlei sub-catchment). Furthermore, Verlorenvlei experiences high evaporation (evaporation best fit line: δ2H = 12.49 x δ18O - 47.68, average δ2H value of 47.1 ‰ and average δ18O value of 7.64 ‰) compared to its feeding rivers. Two sandstone and shale-dominated sub-catchments exhibit overlapping groundwater δ18O and δ2H values and water types to the sub-catchment in the nearest vicinity of Verlorenvlei, suggesting a disproportionately high groundwater contribution from these sub-catchments to Verlorenvlei. Evaluation of Verlorenvlei’s water balance should consider both surface water and groundwater sources, particularly from inter-basin aquifer sources during prolonged droughts.

Hydrophysical Characteristics of Lake Manzherok after Dredging

Data on seasonal and long-term dynamics of hydrophysical characteristics in the water area of Lake Manzheroksky (Altai Republic) after dredging in 2017–2018 are presented. The expedition studies were conducted during the ice age in April 2021, as well as the summer warming of the lake in July 2021 and 2023. The spectral index of light attenuation in the range of 400–800 nm, the relative transparency of water over a white disk, the velocity of water movement in surface and bottom horizons, as well as temperature stratification are studied. It was found that the discovered bottom groundwater sources contributed to the erosion and dissolution of the not completely removed silt layer, which determined high values of the spectral index of light attenuation and low relative transparency of the water. The research results in July 2023 showed significant changes in hydrophysical characteristics compared to 2021, indicating an improvement in the ecological condition of the lake in a long-term aspect for the period from 2018 to 2023.A comparison of spring and summer data on the dynamics of the spectral index of light attenuation at different depths for Lake Manzheroksky with other freshwater low-flow lakes showed that this hydro-optical parameter for the studied lake is maximum during the ice age, while for other lakes its minimum is noted in this phase of the annual limnic cycle.

Integrated geophysical investigations of groundwater for sustainable management in Faisalabad region of Pakistan

As global and local populations surge and climate change continue to disrupt surface and groundwater reservoirs, the urgent need arises to explore additional groundwater sources. Ensuring sustainable management necessitates the efficient identification of high-potential zones to meet escalating water demands. This study aims to delineate groundwater potential zones in Faisalabad District, Pakistan, utilizing a cost-effective geoelectrical resistivity survey method. Apparent resistivity data was collected using the Schlumberger electrode configuration and analyzed with the Interpex “IX1D v2 model” to determine true soil layer resistivities and thicknesses with average root mean square error of 5.12%. The results have revealed that the Aquifer thickness ranged from 13.35 to 165.59 m, and resistivity from 23.96 to 1125.0 Ωm. Hydraulic conductivity, transmissivity, and porosity of aquifers varied from 0.49 to 24.11 m/day (average 8.214 m/day), 35.67 to 1593.98 m2/day (average 567.771 m2/day), and 22.29 to 39.82% (average 37.465%), respectively. Integration of resistivity and geo-hydraulic properties data identified vertical electrical sounding (VES) points 1, 3, 4, and 6 as highly suitable for large-scale freshwater extraction due to having high groundwater potential repositories (coarse sand and gravel formations). Other points had varying suitability: VES points 7 and 8 for shallow wells only, VES points 5, 9, and 10 not recommended due to hard formations, and VES point 2 due to poor groundwater quality. This integrated approach has proven effective in assessing groundwater strata to support Sustainable Development Goal (SDG-3), making it applicable to other geographic locations and informing policy decisions for effective groundwater management.