Aquifer Depth Research Articles

Geophysical reconnaissance of the western basin of the Plaine du Nord aquifer, Haiti

A geophysical reconnaissance was conducted to support aquifer characterization and evaluate groundwater potential in the western portion of the Plaine du Nord aquifer to provision the growing water demands of the city of Cap-Haitien in the Republic of Haiti. Hybrid-source audio-magnetotelluric (HSAMT) soundings and gravity measurements were collected to support the Government of Haiti in sourcing additional water supplies for the city. The Plaine du Nord aquifer is poorly characterized considering it is one of Haiti’s largest aquifers, few drilling logs are available, and only one borehole has investigated the deeper extents of the aquifer. HSAMT supports depth profiling of subsurface resistivity, which supports interpretations of geological strata and groundwater conditions. Gravity measurements allow for complementary mapping of Earth density anomalies and contrasts, which assist in interpreting aquifer thicknesses or depth to bedrock. Pairing HSAMT and gravity methods permitted both an estimation of aquifer thickness and relative changes in sediment characteristics. Gravity results allowed for the mapping of aquifer thickness across the study area, with interpreted thickness greater than 300 m in the coastal zone. HSAMT results cross correlated with available well records and enabled the delineation of zones with increased groundwater potential. The results of the combined methods indicate groundwater storage potential of freshwater in deeper alluvium and emphasize the importance of strengthening resource characterization, modelling and monitoring to guide sustainable resource development and management.

Aquifer system and depth specific chemical patterns in fractured-rock groundwater from the Critical Zone revealed by untargeted LC-MS-based metabolomics

In the Earth's Critical Zone, water plays an essential role as a collector and transporter of metabolites and their transformation products. It is generally believed that the chemical profiles of groundwater are strongly impacted by land use. However, predictors for the effects of above-ground natural and anthropogenic activities on below-ground chemistry are rare. We reasoned that comparing groundwater metabolomes from different land-use sites and depths can give insight into this coupling of above and below-ground processes in the Critical Zone. This study used an LC-MS-based untargeted metabolomic approach to identify links between groundwater metabolomes from monitoring wells in fractured carbonate-/siliciclastic alternations along a hillslope of the Hainich Critical Zone Exploratory (CZE) in Thuringia, Germany. Our results identify the land-use type, aquifer system, and sampling depth as critical factors determining the differences among groundwater metabolomes. We established five groundwater metabolic clusters and correlated these to the aquifer systems, hydrogeochemistry, and microbial community composition. Our untargeted metabolomic approach reveals the limited connectivity of groundwater chemical profiles with above-ground activities and illustrates how deep the input signals can travel.

Site suitability analysis for the construction of water reservoirs in drought‐prone areas of Bangladesh using geospatial techniques

AbstractDrought is becoming a common phenomenon in the northwestern (NW) region of Bangladesh. To address this problem, the government has taken multiple initiatives such as the construction of deep tube wells, re‐activation of abandoned deep tube wells, re‐excavation of canals, construction of cross dams, and digging wells to hold water during monsoon. However, the construction of medium‐ to large‐sized water reservoirs is somewhat overlooked or missed, which can hold large quantities of surface water and, at the same time, can recharge groundwater. Finding suitable sites for water reservoirs is a challenge. The present study aims to fulfill these gaps. We have applied a spatial multi‐criteria technique called the analytical hierarchy process (AHP) to identify suitable sites for water reservoir construction in the drought‐prone NW region of Bangladesh. A total of 12 criteria such as settlement, land use, slope, soil, groundwater depth, road network, river network, vegetation cover, rainfall, geology, protected areas, and aquifer depth were selected. The study shows that 17 percent of the area is highly suitable for reservoir construction, followed by 24 percent moderately suitable and 25 percent marginally suitable. In contrast, approximately 30 percent of the area is unsuitable for reservoir construction. Among 16 districts of northwest region, areas of Rangpur district are mostly suitable (30 percent), followed by Gaibandha district (16 percent). Construction of water reservoir in the identified areas will lower irrigation water pumping costs and will raise groundwater levels in land adjacent to the reservoir in dry season.

Study on Hydrogeochemical Characteristics of Deeply Buried Mining Area in Inner Mongolia-Shaanxi Province, China

Abstract This paper adopted organic components, environmental isotopes, and organic components to study water quality comprehensively, in order to distinguish the differences of hydrogeochemical characteristics between coal measure strata and aquifers on the roof of deeply buried mining areas in Inner Mongolia-Shaanxi, China. The results show that the deeply buried mining area in Inner Mongolia-Shaanxi belongs to Mu Us Desert, and the surface is covered by aeolian sand, with excellent precipitation infiltration capacity. Salinity of surface water and Quaternary water<500 mg/L, the main cation is Ca2+, and the main anion is HCO3-, which belongs to HCO3-Ca·Mg type water. The Cretaceous Zhidan Formation is in unconformable contact with the Quaternary and constitutes a unified water-bearing complex on the whole, which makes Zhidan Formation have a better supply water source, and its inorganic water quality characteristics are close to the Quaternary water. The deep aquifer is affected by the Anding Formation relative impermeable layer and has weak recharge runoff condition. The salinity of Jurassic water is generally >3500 mg/L due to long-term water-rock action. The main cation is Na+, and the main anion is SO42-, which belongs to SO4-Na type water. According to the analysis of hydrochemical characteristics, there is no direct hydraulic connection between Luohe Formation and Zhiluo Formation. The characteristics of environmental isotopes show that the rainwater, surface water, and Quaternary water in the study area belong to the modern groundwater, while Zhidan Formation water is between the modern groundwater and the ancient water. The values of δD and δ18O in the deep Zhiluo Formation and Yan’an Formation are low, and the groundwater falls below the rainwater line of Ordos Basin with a deep circulation depth. Before mining, the groundwater is in a stagnant state with good closed conditions. Qualitative and quantitative signatures of various organic components in water are on the basis of organic geochemistry and hydrogeology, in order to facilitate the study of the quantity, composition, and distribution patterns of organic substances in groundwater and their role in geological, geochemical, and other processes. By testing the organic matter of dissolved organic matter (DOM) in each aquifer, the organic water chemistry characteristics of each aquifer in the Taokutu well field can be established. The content of dissolved organic matter (TOC and UV254) in groundwater decreases gradually with the increase of aquifer depth. Fluorescence peaks in Area I and Area III mainly appeared in surface water and Quaternary water, and DOM sources were more abundant in surface water. The fluorescence peak in Area I also appears in the water of Zhidan Formation, Zhiluo Formation, and Yan’an Formation, and the fluorescence peak between Area I and Area II is a symbol. The fluorescence peak intensity of Cretaceous → Zhiluo Formation in Area V area has an increasing trend, indicating that there are humus-like DOM from other sources in the deep Zhiluo Formation aquifer. In general, the comprehensive analysis of hydrochemical characteristics by various means can well distinguish the differences of hydrogeochemical characteristics among aquifers, which provides a scientific basis for the rapid and accurate discrimination of water situation and disaster in coal mines and the safe production.

Mission to Mars: effective tools for searching and diagnosing water resources

ABSTRACT The identification and evaluation of the quality of water reserves will be needed after the landing of man on the Mars’ surface. To solve this problem, we propose two decision-making systems that result from searching for and estimating the ice thickness or the aquifer depth on Mars. These decision-making systems are based on the use of both multi-channel microwave radiometry, spectral optical tools and the corresponding software. Decision-making systems allow the specification and spatial identification of potential water resources and the evaluation of the depth of the ice-water layer. Algorithms for the functional classification of water samples are proposed and the method for diagnosing water quality is described. The technique is based on the recognition of optical spectral images using a database of spectral patterns. The scheme for passive microwave measurements of ice thickness or groundwater is presented. More efficient radiometers are recommended as components of the microwave decision-making system. The 35-channel spectrophotometer and the 128-channel spectroellipsometer are presented as optical tools for the synthesis of spectral images of ice and water samples. An algorithm of optical inverse task solution is given.

PENENTUAN LOKASI TITIK BOR UNTUK MENDAPATKAN SUMBER AIR BERSIH DESA BANDAR RAHMAT KECAMATAN TANJUNG TIRAM KABUPATEN BATU BARA

Availability of safe access to drinking water is one aspect of the slums of Bandar Rahmat Village. To build a good clean water well, reference data or information is needed regarding the investigation of groundwater potential around Bandar Rahmat Village, Tanjung Tiram Batubara District. This activity conducts geoelectrical testing using the resistivity method to be able to determine the value of rock resistivity which will later be used as a determination of the depth of shallow aquifers and deep aquifers. With the data obtained at each sounding point and correlated with other sounding points so that an aquifer pattern will be formed in the area. This method is used to investigate the subsurface layer based on the level of rock resistivity with groundwater (aquifer) that occupies voids in the geological layer (soil). The vertical geoelectric survey (sounding) is intended to estimate the thickness of the layer containing groundwater. The results of this survey will recommend the right drill point that can be drilled to penetrate the estimated depth so that abundant groundwater will be obtained. The next step is to make a well at the drill point for the people of Bandar Rahmat Village to use for their daily needs.

The biogeochemical responses of hyporheic groundwater to the long-run managed aquifer recharge: Linking microbial communities to hydrochemistry and micropollutants

Interactions of surface water and groundwater (SW–GW) in hyporheic zones produce biogeochemical hotspots. However, response patterns of hyporheic groundwater to external influences remain unclear. In this study, three datasets (hydrochemistry, antibiotics, and microbiome) were collected over a hydrological year to explore the influence of a 12-year managed aquifer recharge (MAR) project. We observed that the long-term MAR practice elevated nutrient and antibiotic levels while reduced redox potential in hyporheic groundwater, and these impacts depended on decreasing SW–GW interaction intensity with aquifer depth. In contrast, the long-term MAR practice increased community dissimilarity of 30-m groundwater but had little impact on 50-m or 80-m groundwater. Moreover, hyporheic community assembly was dominated by dispersal limitation, and thereby co-varied hydrochemistry and antibiotics only attributed to small community variability. The long-term MAR practice decreased species-interaction intensity and changed the abundance of metabolic functions in hyporheic groundwater. Furthermore, predicted community functions involving carbon, nitrogen, sulfur, and manganese cycles for 30-m groundwater showed higher abundances than those for 50- and 80-m groundwater. Collectively, we showed that hyporheic groundwater was sensitive to the SW–GW interaction and human activities, with the interactions of hydrochemistry, contaminants, and microbiome linking to hyporheic groundwater quality and ecosystem functioning.

A Case Study Using Seismic Reflection and Well Logs to Reduce and Quantify Uncertainty During a Hydrogeological Assessment

Building a representative three-dimensional conceptual model of the hydrostratigraphic units is the critical first step when undertaking a hydrogeological assessment. The construction of such conceptual model requires integrating all geological data available for reducing the uncertainty of the conceptual model. In addition, the different types of data collected do not have the same level of uncertainty, and this has to be considered during the modeling. This manuscript presents a geostatistical workflow developed to integrate high resolution seismic reflection data with geological well markers and well logs. The proposed workflow allows reducing and quantifying the uncertainty when developing the conceptual model of hydrostratigraphic units and estimating the spatial distribution of hydraulic conductivity needed to simulate groundwater flow. The study involves the field investigation and numerical modeling for understanding the hydraulic connection between a local sand and gravel esker aquifer overlying a fractured bedrock regional aquifer. Seismic reflection data recorded in 2019 and 2021 significantly modify the conceptual model originally envisioned at site by discovering unknown deep esker extensions. Seismic data also help reducing the spatial uncertainty by delimiting the lateral extents, thickness, and depth of the esker aquifer between existing boreholes. Thickness maps of major hydrostratigraphic units are computed by first interpolating the data with higher uncertainty, which are then locally deformed by successive kriging with external drift to honor data with lower uncertainty. Well logs are then combined with seismic reflection data to better represent the spatial distribution of hydrofacies within the esker aquifer, and identify subunits in the bedrock aquifer. These modifications in the conceptual model of hydrostratigraphic units and the better understanding of the vertical heterogeneity of the hydraulic conductivity significantly impact the simulation of groundwater flow, both regionally and locally at site.

Geochemical identification of particulate lead pollution in shallow groundwater in inhabited areas in Kabwe, Zambia

The town of Kabwe has been exposed to the most severe lead pollution due to mining activities in the 20th century. A large tailing (slag) hill containing over 1% of Pb is still standing within the mine's licensed area. We analysed the chemical composition and lead isotope ratios in seventeen shallow wells, five deep wells in the inhabitants' area, three ponds and three borehole wells in the area of the mine, and in the surrounding areas, we examined two samples from the soil's surface and nineteen 1-m deep core samples at each of the 15 sites. We found low dissolved Pb (<0.04 μg/L) but high particulate Pb concentrations (2–100 μg/L) in seventeen shallow groundwater samples (aquifer depth of ca. 10 meters). Five shallow wells exceeded the World Health Organization (WHO) guideline (10 μg/L) for total-Pb concentration. However, three of the five shallow wells had low dissolved Zn and sulphate ion concentrations (<1 μg/L; <50 mg/L), suggesting a low amount of Pb transfers through the aquifer. The isotopic water and soil samples data clarified that the Pb pollution in the shallow groundwaters is derived from the tailings deposit.Most of the shallow groundwater samples had negative cerium (Ce) anomaly in the rare earth element (REE) pattern, indicating contributions of colloidal transport from the dolomite aquifer in this area. However, PHREEQC modelling shows that migration by hydroxide colloids from the mining area does not explain the high particulate lead concentrations in the well water. The positive correlation between Pb/Ce and Pb/Al ratios in the particulates exhibited that the lead pollutants were derived from the aluminosilicates on the land. The estimated Pb contents in particulates in most shallow-well water were 700–2800 mg/L, and they distributed geographically similar to the Pb bulk concentration contour map of the surface soil. The analysis of the grain-size fractions in a 2-km transect soil demonstrated that Pb was eight times enriched in the silt fraction (<53 μm) than a very coarse sand fraction (1–2 mm). Therefore, we hypothesized that the particulates in the well water were mainly derived from the aeolian dust (>0.45 μm) at the well site. Further studies are required to examine the hypothesis.

Evaluation of Geophysical and Geochemical Characteristics of Soil and Groundwater Resources in Yenagoa Environs, Niger Delta, Nigeria

The problem of potable water has increased in recent time due to increase in population density, petroleum exploration activities and spillages along the creeks. Thus, three (3) Vertical Electrical Soundings (VES) were made using Schlumberger array in the study location to obtain geophysical data, using the ABEM SAS 1000 terrameter, in order to investigate the occurrence of groundwater in relation to the depth and thickness of viable aquifer. Six (6) surface water samples and six (6) subsoil samples were obtained from the study area. Both subsoil and surface water samples were analyzed to determine the concentration of contaminant. Analysis was performed using the Atomic Absorption Spectroscope (AAS) method which was compared with the World Health Organization Standard. Result and interpretation of analyses revealed high contaminant contents of lead (Pb) with values of subsoil samples at S2 (18 mg/l) and S6 (8.1302 mg/l), while Mn show very high concentration of contaminant values for all subsoil samples which exceeded the WHO permissible standard which indicates that aquifer may likely be polluted by intrusion. Cr for subsoil samples and Mn of surface water samples are likely within or slightly higher concentration value when compared with WHO limit. It is advisable to carry out proper water treatment from source and soil degradation, for potable drinking water and cultivation of agricultural product respectively.

Integrated Geoelectrical Resistivity Method for Environmental Assessment of Landfill Leachate Pollution and Aquifer Vulnerability Studies

Leachate plumes from landfills are a major source of pollution in Nigeria, especially in urban areas. Assessing leachate contamination in the subsoil is considered a complex process that needs detailed field measurement to accurately define the extent of contamination. To ascertain the extent of pollution of the subsoil and groundwater sources which were reportedly contaminated by leachate plumes from an old dumpsite located in Osubi town, an integrated geo-electrical method involving 1-D vertical electrical sounding (VES) and 2-D, 3-D ERT techniques were employed. Orthogonal set of 2-D apparent resistivity data was collected in a 100 × 50 m2 rectangular grid around the dumpsite, using the Wenner array. Two years later, three (3) 2-D resistivity imaging profiles were also recorded in time-lapse mode at the dumpsite to monitor the possible effects of attenuation on the leachate over time. Ten (10) VES data were also acquired and used along with the 2-D imaging data. 2-D apparent resistivity data were inverted with Dipprowin software program. The orthogonal set of 2-D lines of apparent resistivity was merged into 3-D data and inverted with RES3DINV program to create a 3-D subsurface resistivity model. Geological models observed from 2-D and 3-D resistivity inversion revealed low resistivity values in the order ρ Ω·m which is indicative of leachate plumes in the saturation zone (pore water). The 2-D resistivity-depth sections imaged low resistivity leachate plumes at the near surface (ant within the first, second and third layers at depth ranging from 0.00 - 2.50 m, 2.50 - 5.38 m and 5.38 - 8.68 m respectively. Thus, leachate contamination clearly increased with depth beyond the depth of first and second aquifers in the area which implies that available groundwater for domestic use is already contaminated with leachate from the dumpsite. Leachate contaminant-depth map estimated for the second geoelectric layers for VES 2, 3, 4, 7, 8, 9, and 10 shows that the second layer has been invaded completely by leachate contamination up to 6.5 m depth. 2-D apparent resistivity data acquired two years after show lower resistivity anomalies of the leachate plume caused by time-lapse attenuation effect on the observed resistivity of the leachate. This indicates that the leachate plume has become more conductive and toxic to the environment. The Longitudinal conductance map of the area shows that the aquifer protective capacity of this area is weak (0.1 - 0.19 Mho) thus, aquifers in the area are prone to pollution from the dumpsite. The three techniques used in this study (2-D, 3-D ERT and 1-D VES) fitly provided crucial information on the degree of contamination caused by the landfill leachate plume. Therefore, it is advisable to implement an environmental remediation and leachate management program.

Chemical composition of groundwater in the zone of slow water exchange of the Upper Pontian aquifer, Northwestern Bulgaria

The Upper Pontian aquifer occupies the central part of the Lom Depression. The geological position determines its gradual dipping from the periphery to the central parts. It is one of the most water-abundant aquifers in Northwestern Bulgaria and is associated with the sands of the Archar Formation. The chemical composition of the waters is of interest and is important for the water supply in the area. The analysis of the data shows that there are regularities in the change of the water quality with aquifer depth. Significant differences in some of the hydrochemical parameters are found in the zone of slow water exchange and geological and hydrogeological explanations have been sought.

Integrated geophysical and geochemical assessment of submarine groundwater discharge in coastal terrace of Tiruchendur, Southern India

Submarine groundwater discharge (SGD) study is essential for groundwater in coastal terrace at Tiruchendur. The famous Murugan Temple is located in the area and around 25,000 people who visit this temple use the SGD well water at NaaliKinaru (a small open well) as holy water and drink it. The rock and soil type are sandy clay, silt, beach sand, calcarenite, kankar, gneissic rock and charnockite in base rock. Megascopic identification method was used to identify the porous and permeable rocks such as calcarenite, sandstone and kankar to support to increase SGD flux. Grain size study was used to identify the paleo-coastal estuarine environment with sediment deposits in the terrace. The square array electrical resistivity method was used to study the subsurface geology and aquifer depth. The 2d ERT technique was used to identify the subsurface shallow perched aquifer of freshwater. The magnetotelluric survey method was used to scan the entire subsurface geological and tectonic uplift, coastal ridges, rock folded subsurface structural features of continental and oceanic tectonism. Darcy’s law was used to calculate the SGD flux rate in the above study area.

Effects of River Partial Penetration on the Occurrence of Riparian Freshwater Lenses: Experimental Investigation

AbstractThis study examines the occurrence of riparian lenses adjacent to partially penetrating, gaining rivers under the controlled conditions of a laboratory sand tank. Laboratory experiments and numerical modeling of the freshwater lens extent are used to provide physical verification (in light of limited examples of well‐characterized field cases) of the analytical methodology, thereby evaluating the underlying assumptions. Parameter calibration and uncertainty analysis are applied to assess both the experimental conditions and the benefit of lens observations in applying the analytical approach. The experimental freshwater lens was reproduced by both analytical and numerical models, with the exception of small mismatches (between analytical results and measured data) in the lens thickness in the near‐river region. These are most likely due to vertical flow effects that arise from the partial river penetration and saltwater inflows to the river bottom, and that are only partly accounted for in the analytical approach. Uncertainty analysis highlighted that accurate lens predictions based on the analytical method requires calibration to direct lens measurements; a similar finding from earlier studies of fully penetrating river conditions. Sensitivity analysis highlighted that the saltwater head boundary, freshwater and saltwater densities, and the aquifer depth below the riverbed (in descending order of sensitivity) are the most important factors in controlling freshwater lens occurrence and saltwater discharge. The results provide the first physical verification of the occurrence of stable riparian lenses adjacent to partially penetrating, gaining rivers, and verify a recent analytical solution for lens extent and saltwater discharge.

Water Richness Zoning and Evaluation of the Coal Seam Roof Aquifer Based on AHP and Multisource Geological Information Fusion

Roof water disaster is one of the most serious disasters in the process of coal mine safety mining in China. The thickness of modern comprehensive mechanized coal mining is large, which has a great impact on the roof aquifer, and the threat degree of water disaster is also increasing. Therefore, the evaluation of the water richness of the roof aquifer is an important work for coal mine water prevention and control. In order to systematically evaluate the water-rich property of an aquifer in a coal seam roof, this paper couples multisource geological information based on an analytic hierarchy process (AHP). The characteristics of the roof aquifer, hydrogeology, and structure are determined to be the main control factors of K2 limestone water richness evaluation. Under the main control factors, seven independent water richness evaluation indexes, including aquifer depth, aquifer thickness, borehole water level, borehole water consumption, faults, folds, and collapse columns, are divided, and a normalized water richness coupling evaluation model is constructed, which realizes the zoning and evaluation of a water-rich aquifer in a coal seam roof.

Infiltration coefficient, percolation rate and depth-dependent specific yields estimated from 1.5 years of absolute gravity observations near a recharge lake in Pingtung, Taiwan

An efficient underground reservoir management requires reliable hydrogeological parameters, such as infiltration coefficient, percolation rate and specific yield (Sy) values. The cross-well pumping test is a well-known method for determining Sy, but different unsaturated flow models can lead to various Sy results. Heterogeneity in unsaturated and saturated zones can restrict well-dependent methods in estimating these parameters on a regional scale, for which an alternative, gravity-based method is attempted in this study. We established an absolute gravity site at the Wanlong Primary school (WLPS) near a recharge lake (an artificial lake) in the Pingtung Plain and collected 1.5 years of gravity data in 2019–2020. Around a monsoonal rain event in late May 2020, gravity values underwent three stages of changes. The first stage experienced a rapid gravity rise of 18 μgal from infiltrated rain, followed by stable gravity values in the second stage when the infiltrated rain recharged the aquifer, and the third stage showed a persistent gravity increase with rising groundwater level. The gravity-based estimate of infiltration coefficient is 0.84 ± 0.14, and the percolation rate is about 15 m/day, suggesting that WLPS is over a high infiltration region. A depth-dependent Sy profile up to 30 m depth was constructed using gravity and groundwater data. In the dry season, it was found that Sy values are higher at the aquifer depths of 22–28 m than in the shallow part. However, some Sy values determined in the wet seasons are overestimated due to high soil water content (SWC) changes, which induced particularly large gravity changes in the 30-m unsaturated zone of WLPS when the wet season started. This study confirms the advantage of using high precise gravity measurements (at one μgal level) and hydrology records for regional hydrogeological parameter estimation.

Geophysical Delineation of Freshwater–Saline Water Interfaces in Coastal Area of Southwest Bangladesh

Insufficiency of potable water is acute in southwest (SW) coastal areas of Bangladesh. The local population ignores the depth to saltwater/freshwater interface causing many unsuccessful waters wells drilling. In this context, a combined use of borehole logs, geophysical well logs, vertical electrical soundings (VES), electrical resistivity tomography (ERT) and electrical conductivity (EC) of sampled waters was performed to identify saltwater/freshwater interface depths in this coastal part. The study shows that the depth to freshwater/saltwater interface varies from place to place occurring commonly between 190 to 285 m, and locally as shallow as 146 m. The shallow freshwater/saltwater interface depth is greatly influenced by the upconing of fresh water from the deep aquifer (DA) near the major rivers and coast compared to the landward part and is mixed with more saline waters above. Vertically infiltrated saltwater is the main cause of brackish water in the upper shallow aquifer (USA), which is hydraulically connected with the lower shallow aquifer (LSA), and not directly recharged from the Bay of Bengal in the south. The study will contribute to find out the depth of the potential freshwater aquifer and assess the aquifer vulnerability in the coastal area of SW Bangladesh.

Investigation of Aquifer Zone in Tambakromo Village, Ponjong Subdistrict, Gunung Kidul Regency, Yogyakarta, Indonesia

The presence of surface water is always being a primary issue in Gunung Kidul regency. An aquifer investigation would support groundwater exploration. The research area is located in Tambakromo village, Ponjong subdistrict, Gunung Kidul Regency, Daerah Istimewa Yogyakarta Province. The aim of this research is about geological and subsurface conditions based on geological data and geoelectrical resistivity methods. By resistivity value interpretation, the position, depth, and thickness of aquifer could be determined. The purpose of this research is to identification of geological conditions that supported being aquifer rock. The method in this research is used geological mapping combined with petrographic analysis. The geophysics method is used to identification of aquifer in research area. Three locations were selected to acquisition geoelectrical resistivity survey. In Grogol village, there is no aquifer based on resistivity values of more than 10000 ohmmeters (andesitic breccia). An akuifuge is interpreted there in andesitic breccia instead of the presence of aquifer. The tuffaceous is interpreted as lapillistone that contained the glass with resistivity value of 43.63 and 340.11 ohmmeters. The Garon and Sumberejo village have aquifer at depth of 50 to 80 meters with a thickness of 13 to 70 meters. The type of aquifer in both area is included an unconfined aquifer, specifically located in between the limestone rock layer and andesitic breccia. By regional stratigraphic correlation, tuffaceous lapillistone is interpreted as derived from Semilir Formation. In addition, the presence of aquifer in research area could recommend for local people and government to reduce the drought disaster.

Groundwater Quality Issues and Challenges for Drinking and Irrigation Uses in Central Ganga Basin Dominated with Rice-Wheat Cropping System

Increased population and increasing demands for food in the Indo-Gangetic plain are likely to exert pressure on fresh water due to rise in demand for drinking and irrigation water. The study focuses on Bhojpur district, Bihar located in the central Ganga basin, to assess the groundwater quality for drinking and irrigation purpose and discuss the issues and challenges. Groundwater is mostly utilized in the study area for drinking and irrigation purposes (major crops sown in the area are rice and wheat). There were around 45 groundwater samples collected across the study region in the pre-monsoon season (year 2019). The chemical analytical results show that Ca2+, Mg2+ and HCO3− ions are present in abundance in groundwater and governing the groundwater chemistry. Further analysis shows that 66%, 69% and 84% of the samples exceeded the acceptable limit of arsenic (As), Fe and Mn respectively and other trace metals (Cu, Zn, Pb, Cd) are within the permissible limit of drinking water as prescribed by Bureau of Indian Standard for drinking water. Generally, high As concentration has been found in the aquifer (depth ranges from 20 to 40 m below ground surface) located in proximity of river Ganga. For assessing the irrigation water quality, sodium adsorption ratio (SAR) values, residual sodium carbonate (RSC), Na%, permeability index (PI) and calcium alteration index (CAI) were calculated and found that almost all the samples are found to be in good to excellent category for irrigation purposes. The groundwater facie has been classified into Ca-Mg-HCO3 type.

Multi-criteria analysis techniques to enhance sustainability of water pumping irrigation

Traditionally, the groundwater resource has supported extensive agricultural irrigation, mainly based on fossil fuels for pumping purposes. However, current international agreement and policies are promoting climate change mitigation and sustainable development in most of sectors. With this aim, the main challenge presented by groundwater pumping solutions is then focused on reducing their fossil fuel dependence and integrating renewables, while also accounting for sustainability criteria. Under this framework, this paper analyzes and compares different Multi-Criteria Decision Analysis – TOPSIS, VIKOR and SIMUS – for a set combinations of water storage options and groundwater pumping energy resources. These alternatives are firstly ordered according to each decision-making approach to fulfill energy, economic and environmental requirements. Subsequently, these prioritized alternatives are then compared depending on subjective criteria weights (TOPSIS and VIKOR) or objective and quantitative methodologies (SIMUS). Case study based on a Spanish aquifer is included in the paper, identifying 72 potential combinations of real agricultural requirements (aggregated crop area, crop irrigation demand) and water resource availability (in terms of aquifer depth). The selected most appropriate alternatives for each decision-making approach are then compared and discussed in detail. This work highlights the relevance of subjective criteria weights, and compares the results to other decision-making approach where the experts’ assessment of the criteria is not required by the methodology.