Aquifer Formation Research Articles

Investigation of the Origin of Hueco Bolson and Mesilla Basin Aquifers (US and Mexico) with Isotopic Data Analysis

An important tool to identify the origin of a groundwater resource is the use of isotopic signatures. Isotopic signatures give us the age of water and provide information as to the water’s origin, potential transit at geologic structures, source of salinization, and possible recharge points. The purpose of this study was to collect and analyze well samples to evaluate isotopic tracers (δ18O and tritium) in the transboundary Conejos-Médanos/Mesilla aquifer located between the US and Mexico. This new analyzed information was compared with the isotopic information available in the US Mesilla and US-MX Hueco basins generated by previous works, which described the common origin of the Hueco Bolson and Mesilla Basins aquifers. This study used isotopic analysis to validate the theory of the original formation and interconnectivity of both transboundary basins. This research presents new data of δ18O and tritium, and a comparison with previous published data from other workers, versus the known global meteoric water line (GMWL) and the Rio Grande evaporation line (RGEL). Results show that the groundwater at the transboundary aquifer features an evaporated isotopic signal, which is consistent with referenced published data that discusses the geologic history of aquifer formations at the studied area. This study is important because isotopic studies from the area were nonexistent and because isotopic data can explain recharge scenarios that relate to groundwater quality.

Spatial modeling of groundwater depth fluctuations using co-active neuro-fuzzy\xa0inference system (CANFIS) and geographic information system (GIS)

Groundwater drawdown and reduction of groundwater resources are serious problems in the water supply. Unfortunately, sufficient and accurate data on the groundwater depth fluctuations values are not available in all plains of the world. In the present study, a co-active neuro-fuzzy inference system (CANFIS) network and geographic information system (GIS) were used to simulate the annual groundwater drawdown values on the southern coasts of the Caspian Sea (Iran). For this purpose, the annual drawdown values in 250 piezometric wells as the output variable were evaluated. Further, the effective factors in groundwater depth fluctuations were evaluated as inputs of the CANFIS network, including water table depth, annual precipitation, annual evaporation, the transmissivity of aquifer formations, topography, distance from the sea, distance from water sources, population density, and withdrawal values in the influence radius of the study wells. The modeling process was performed in three stages: training, cross-validation, and test. According to the results, the CANFIS network has a high performance in modeling groundwater drawdown ​​(training R-sqr = 0.97; test R-sqr = 0.82). Then, the inputs of the tested network were prepared in the GIS in raster format for the study plain. The tested network was used to simulate the annual fluctuations of groundwater depth ​​in the plain and the simulation results were presented in the GIS as an annual groundwater drawdown map. Overlap and comparison of the observed values ​​of groundwater drawdown and the simulated values ​​in the map indicate the high performance of the CANFIS network (R-sqr = 0.81). Therefore, the used methodology can be applied to simulate the annual drawdown of groundwater depth in plains without groundwater depth data.

Prediction of groundwater drawdown using artificial neural networks.

Groundwater drawdown is typically measured using pumping tests and field experiments; however, the traditional methods are time-consuming and costly when applied to extensive areas. In this research, a methodology is introduced based on artificial neural network (ANN)s and field measurements in an alluvial aquifer in the north of Iran. First, the annual drawdown as the output of the ANN models in 250 piezometric wells was measured, and the data were divided into three categories of training data, cross-validation data, and test data. Then, the effective factors in groundwater drawdown including groundwater depth, annual precipitation, annual evaporation, the transmissivity of the aquifer formation, elevation, distance from the sea, distance from water sources (recharge), population density, and groundwater extraction in the influence radius of each well (1000m) were identified and used as the inputs of the ANN models. Several ANN methods were evaluated, and the predictions were compared with the observations. Results show that the modular neural network (MNN) showed the highest performance in modeling groundwater drawdown ​​(Training R-sqr = 0.96, test R-sqr = 0.81). The optimum network was fitted to available input data to map the annual drawdown ​​across the entire aquifer. The accuracy assessment of the final map yielded favorable results (R-sqr = 0.8). The adopted methodology can be applied for the prediction of groundwater drawdown in the study site and similar settings elsewhere.

New Evidence for Linking the Formation of High Arsenic Aquifers in the Central Yangtze River Basin to Climate Change Since Last Glacial Maximum

New Evidence for Linking the Formation of High Arsenic Aquifers in the Central Yangtze River Basin to Climate Change Since Last Glacial Maximum

Многофункциональная двухъярусная осушительно-увлажнительная система

The purpose of the research is to reduce the period between the snow melt and the readiness of the soil for cultivation on weakly sloped lands with characteristic seasonal freezing and the formation of temporary aquifers in the form of perched water in early spring, as well as to ensure the required water-air regime of the soil at different time of crops cultivation. The object of the study is horizontal closed drainage systems. A multifunctional two-tier drainage and humidifi cation system is proposed, the drains of which are connected to closed collectors of the lower and upper tiers, respectively. In the moutth zone, the collector of the upper tier is connected to the collector of the lower tier and a hydraulic valve is installed above the point of their connection in the collector of the lower tier. The operation of the system in the drainage mode occurs in two stages. At the fi rst stage, the upper tier works, ensuring the removal of excess water from the thawed topsoil layer in early spring. At the second stage, after complete seasonal thawing, in addition to the drains of the fi rst tier, the drains of the lower tier are included in the work. Joint work in the drainage mode of the upper and lower tiers ensures the required humidity of the topsoil layer and maintains the groundwater level at a level corresponding to the drainage rate. In the dry period, water from the canal, entering the mouth of the collector system, with the help of a hydraulic valve, blocks the collector of the lower tier and continues to fill the upper tier system, supplying water to the root layer of the soil.

ВИКОРИСТАННЯ ЧАСОВОГО ТА ПРОСТОРОВОГО РОЗПОДІЛУ ТРИТІЮ ДЛЯ ІНДИКАЦІЇ ЗМІН СТАНУ СЕНОМАН-КЕЛОВЕЙСЬКОГО КОМПЛЕКСУ ПИТНИХ ПІДЗЕМНИХ ВОД НА ТЕРИТОРІЇ МІСТА КИЄВА

The presented research is devoted to study and establishment of the spatiotemporal change of tritium content in groundwater of CenomanianCallovian groundwater complex in Kyiv and the causes of these changes in order to identify water exchange features and hydraulic interaction between shallow and deep aquifers, as well as between groundwater and surface waters. Due to the excessive use of groundwater, depressive surfaces of hydrodynamic pressures have formed, aquifers are transforming from pressure head to pressureless, and there is a danger of downward filtration and contamination of potable groundwater. Also, one of the effects of these depressions formation is deterioration of water quality. However, to study the conditions of the qualitative composition formation of deep potable aquifers and to identify the causes of changes in groundwater status is a difficult and responsible task at the same time. Methods of isotopic hydrogeology are among the main scientific methods used to track the peculiarities of groundwater movement and assess their age. The new data obtained by isotopic methods help to control water resources and allow to make such decisions that will bring socio-economic benefits. The obtained data of tritium content in groundwater of Cenomanian-Callovian groundwater complex, clearly presented in the form of maps, allow to make informed decisions on sustainable resource management, and regular monitoring of chemical and isotopic composition of groundwater reveals mechanisms of recharge and sources of pollution, which were not taken into account before. The results obtained by the authors through statistical and spatial analysis of tritium content in groundwater during 2014-2017, indicate that currently within the territory of Kyiv there is a positive trend towards a slow gradual return of Cenomanian-Callovian groundwater complex to its natural state.

Trace Metals Evaluation of Groundwater in the Granito-Basaltic Fractured Rock Aquiferous Formations in Bafoussam, West Region—Cameroon

Trace Metals Evaluation of Groundwater in the Granito-Basaltic Fractured Rock Aquiferous Formations in Bafoussam, West Region—Cameroon

Fully Mechanized Mining Technology and Practice of Water Conservation with Large Gravity Filling of Aeolian Sand‐Like Paste

Aiming at the serious problem of Salawusu formation aquifer damage caused by caving mining in Yuyang coal mine, the technique of mechanized backfill mining with Aeolian sand‐like paste was invented. Aeolian sand was used as aggregate and alkali‐activated fly ash as cementing agent in the backfill material. Slurry ratio was studied where the water‐sand ratio was 1 : 1.3 and the mass concentration was 72%, while slurry initial fluidity could reach 210 m. The author proposed the local resistance loss calculation method of slurry pipeline transportation, and the field gravity transport test results showed that resistance loss of unit length elbow was 4.26 times as big as loss of resistance along path; thus the pipeline diameter with 14.9 gravity of self‐flowing was determined, and the pipeline flow design precision was improved by more than 10%. The backfill capacity could reach 360 m3/h and the running energy consumption was lower because of adopting backfill station model with double pulping system and underground equipment pool. The author also put forward whole backfill space sealing in which cloth consumption was only 40% of bag backfill. Industrial test showed that the backfill mining technique met requirements of water resources protection, primarily because the filling rate was 98.5% in goaf, strata behavior appeared slightly, roof water leaching was less than 2 m3/d, and surface subsidence value was only 38 mm. There were great breakthroughs in cost and production efficiency in this technology compared with similar technologies.

A Further Application of Coefficient of Anisotropy and Reflection Coefficient as Indices in Delineating Groundwater Potential in Basement Complex of Ado Ekiti, Southwestern Nigeria

One index might not be enough in geophysical investigation of underground water potentials in basement terrain, there is a need to look into other indices for an improved investigation, the combination of some indices will lead credence to the result hence this work is a further application of coefficient of anisotropy, reflection coefficient and fracture coefficient on spatial distribution of underground water in Ado Ekiti basement complex. This work examined the thickness of aquifer, its resistivity spread and other hydro geological parameters such as total longitudinal conductance, total transverse resistances, coefficient of Anisotropy, reflection coefficient and fracture contract to determine water potentials in the study area. Resistivity and thickness are linearly related for high productive Aquifer formation, thus these indices generated from thickness and resistivity have been examined in other to determine the porosity and permeability and hence transmissivity of the aquiferous zone in the study area. Aquifer resistivity ranges from 7.7Ωm to 545Ωm in weather zone and between 9.5Ωm to 1902.6Ωm in fracture zone these values are within productive range in basement complex environment. Shallow basement of less water potential have been found in part of North west and north east of the study area, total transverse resistance also discovered low porosity at Aiyedun quarters, Elemi housing Estate and Ita Eku these are hard rock zone, this area has also been identified through their coefficient of anisotropy as low or none productive zone the coefficient of anisotropy is higher than 1.5. Area of promising water bearing zone are with the North west, west, south west and south east of the study area.

Modeling CO2 migration in a site-specific shallow subsurface under complex hydrodynamics

Potential pathways in the subsurface may allow upward migrating CO2 from deep geological storage reservoirs into shallow subsurface aquifers. Detailed simulations of CO2 migration in the near surface are necessary for monitoring design where the near-surface groundwater flow field is usually complicated by rainfall and pumping wells. This work studied the CO2 migration under complex hydrodynamic conditions by numerical simulation for a specific site. Results shows that in a coupled soil and aquifer formation, the leakage rate of CO2 dominates the whole migration process, especially in the vadose zone. The groundwater velocity determines the lateral distance of CO2 migration with the groundwater flow, and simultaneously weakens the upward migration trend. Under certain conditions, such as the leakage rate of 1 × 10−5 kg/s and the groundwater velocity of 6.7 × 10−8 m/s, upward migration of CO2 is completely suppressed, therefore it will not leak to the surface. Both rainfall and pumping wells affect the migration indirectly by changing the groundwater flow field, while the impact of the latter is greater. When the well extraction increases or the well is downstream of the leak, CO2 will be extracted to the well. The permeability heterogeneity will also promote migration. Complex groundwater environments require more attention in the monitoring work.

Aquifer Storage and Recovery in Layered Saline Aquifers: Importance of Layer-Arrangements

Aquifer storage and recovery (ASR) refers to injecting freshwater into an aquifer and later withdrawing it. In brackish-to-saline aquifers, density-driven convection and fresh-saline water mixing lead to a reduced recovery efficiency (RE, i.e., the volumetric ratio between recovered potable water and injected freshwater) of ASR. For a layered aquifer, previous studies assume a constant hydraulic conductivity ratio between neighboring layers. In order to reflect the realistic formation of layered aquifers, we systematically investigate 120 layered heterogeneous scenarios with different layer arrangements on multiple-cycle ASR using numerical simulations. Results show that the convection (as is reflected by the tilt of the fresh-saline interface) and mixing phenomena of the ASR system vary significantly among scenarios with different layer arrangements. In particular, the lower permeable layer underlying the higher permeable layer restricts the free convection and leads to the spreading of salinity at the bottom of the higher permeable layer and early salt breakthrough to the well. Correspondingly, the RE values are different among the heterogeneous scenarios, with a maximum absolute RE difference of 22% for the first cycle and 9% for the tenth cycle. Even though the difference in RE decreases with more ASR cycles, it is still non-negligible and needs to be considered after ten ASR cycles. The method to homogenize the layered heterogeneity by simply taking the arithmetic and geometric means of the hydraulic conductivities among different layers as the horizontal and vertical hydraulic conductivities is shown to overestimate the RE for multiple-cycle ASR. The outcomes of this research illustrate the importance of considering the geometric arrangement of layers in assessing the feasibility of multiple-cycle ASR operations in brackish-to-saline layered aquifers.

Comparison of Self-Organizing Map, Artificial Neural Network, and Co-Active Neuro-Fuzzy Inference System Methods in Simulating Groundwater Quality: Geospatial Artificial Intelligence

Water quality experiments are difficult, costly, and time-consuming. Therefore, different modeling methods can be used as an alternative for these experiments. To achieve the research objective, geospatial artificial intelligence approaches such as the self-organizing map (SOM), artificial neural network (ANN), and co-active neuro-fuzzy inference system (CANFIS) were used to simulate groundwater quality in the Mazandaran plain in the north of Iran. Geographical information system (GIS) techniques were used as a pre-processer and post-processer. Data from 85 drinking water wells was used as secondary data and were separated into two splits of (a) 70 percent for training (60% for training and 10% for cross-validation), and (b) 30 percent for the test stage. The groundwater quality index (GWQI) and the effective water quality factors (distance from industries, groundwater depth, and transmissivity of aquifer formations) were implemented as output and input variables, respectively. Statistical indices (i.e., R squared (R-sqr) and the mean squared error (MSE)) were utilized to compare the performance of three methods. The results demonstrate the high performance of the three methods in groundwater quality simulation. However, in the test stage, CANFIS (R-sqr = 0.89) had a higher performance than the SOM (R-sqr = 0.8) and ANN (R-sqr = 0.73) methods. The tested CANFIS model was used to estimate GWQI values on the area of the plain. Finally, the groundwater quality was mapped in a GIS environment associated with CANFIS simulation. The results can be used to manage groundwater quality as well as support and contribute to the sustainable development goal (SDG)-6, SDG-11, and SDG-13.

Aquifer storage of treated wastewater for subsequent recovery as an important strategy for sustainable water security in Kuwait

Abstract This research explores the possibility of creating an underground water reservoir by injecting treated wastewater and evaluates the recovery efficiency and water quality under different injection/recovery scenarios. An injection/recovery well was established in the Dammam Formation aquifer in Kuwait. Six observation wells were also drilled nearby to monitor the water levels and quality. A three-dimensional (3D) numerical hydraulic and transport model was set up using the coupled version of MODFLOW and MT3DMS. Four scenarios of cyclic and continuous injection with different injection and pumping rates stretching over 5,400 days were investigated. Two dispersivity values, low (10 m) and high (200 m), were used in each scenario in order to establish the minimum and maximum recovery limits of useful water that can be expected from the site. The combination of injection rate of 650 m3/d and subsequent recovery at 1,000 m3/d proved to be the optimum option for the storage of water, resulting in good recovery efficiency and acceptable water quality. Based on these results, it was concluded that aquifer storage is a feasible strategy for mitigating growing water scarcity in the State of Kuwait and other countries in the larger Middle East.

Recycling of drainage brines by means of re-injection in Udachny Mine

The permafrost zone in Levoberezhny 2 Site, represented by the Upper Cambrian carbonate–terrigenous rock strata up to 270 m thick, is studied. It is found that during injection, brines first flow along fractures and pores, and dissolve ice fill in them. The permafrost rocks degenerate as a result, and extra porosity is generated together with formation of a manmade aquifer. The analytical flow model of brine disposal in permafrost rocks in Udachny Mine represents the analytical flow model in dry soil, with rock permeability varied from zero to maximum values to describe frozen and thawed zones. The hydrogeological research of permeation by the numerical modeling method used GMS MODFLOW environment. The key complexity of the permeation problem consists in the fact that permeability coefficient and storage capacity of permafrost rocks greatly increase with time of injection. The highest degradation of ice takes place in the injection site; brines are displaced deeper in rock mass at the front velocity governed by density of joints, ice content, injection flow rate, mineralization of brines, temperature of rock mass and brines, etc. The permeation problem was solved using the method of alternation of quasi-stationary states in conformity with the modern hydrogeology and frost in the permafrost rock mass, and in accord with experience of drainage brine re-injection in Udachny Mine, subject to the key requirement of free flow of drainage brine into the permafrost rock zone at the eliminated discharge of water into local stream flows.

Sensitivity Analysis of the Parameters Affecting Bottom-hole Pressure during Foam Underbalanced Drilling

With many advantages of protecting reservoir, increasing drilling speed and high capacity in carrying cuttings, foam drilling is suitable for drilling through the aquifer and natural fractured formation, and has been developed fast since 1990s. However, the change of the foam physical properties along wellbore, and the flowing state of the foam in the annulus is complex. Therefore, it is difficult to optimize the design of hydraulic parameters for foam drilling. In order to solve this problem, the mathematical model for foam-cutting flowing in annulus has been developed. In addition, the sensitivity analysis has been conducted about the factors affecting the parameters of foam drilling and the characteristics of foam flowing. The analyzing results can provide the foundation for designing the hydraulic parameters of foam drilling.

Parameter Identification by High-Resolution Inverse Numerical Model Based on LBM/CMA-ES: Application to Chalk Aquifer (North of France)

The present paper proposes the numerical solution of an inverse problem in groundwater flow (Darcy’s equation). This solution was achieved by combining a high-resolution new code HYSFLO-LBM (Hydrodynamic of Subsurface Flow by Lattice Boltzmann Method), based on LBM, to solve the direct problem, and the metaheuristic optimization algorithm CMA-ES ES (Covariance Matrix Adaptation-Evolution Strategy) to solve the optimization step. The integrated optimization algorithm which resulted from this combination, HYSFLO-LBM/CMA-ES, was applied to the hydrogeological experimental site of Beauvais (Northern France), instrumented by a set of sensors distributed over 20 hydrogeological wells. Hydrogeological parameters measured by the sensors are necessary to understand the aquifer functioning and to serve as input data for the identification of the transmissivity field by the HYSFLO-LBM/CMA-ES code. Results demonstrated an excellent concordance between the integrated optimization algorithm and hydrogeological applied methods (pumping test and magnetic resonance sounding). The spatial distribution of the transmissivity and hydraulic conductivity are related to the heterogeneous distribution of aquifer formations. The LBM and CMA-ES were chosen for their proven excellent performance and lesser cost, in terms of both money and time, unlike the geophysical survey and pumping test. The model can be used and developed as a decision support tool for integrated water resources management in the region.

Physical limits to meltwater penetration in firn

AbstractProcesses governing meltwater penetration into cold firn remain poorly constrained. Here, in situ experiments are used to develop a grain-scale model to investigate physical limitations on meltwater infiltration in firn. At two sites in Greenland, drilling pumped water into cold firn to >75 m depth, and the thermo-hydrologic evolution of the firn column was measured. Rather than filling all available pore space, the water formed perched aquifers with downward penetration halted by thermal and density conditions. The two sites formed deep aquifers at ~40 m depth and at densities considerably less than the air pore close-off density (~725 kg m−3at −18°C, and ~750 kg m−3at −14°C), demonstrating that some pore space at depth remains inaccessible. A geometric grain-scale model of firn is constructed to quantify the limits of a descending fully saturated wetting front in cold firn. Agreement between the model and field data implies the model includes the first-order effects of water and heat flow in a firn lattice. The model constrains the relative importance of firn density, temperature and grain/pore size in inhibiting wetting front migration. Results imply that deep infiltration, including that which leads to firn aquifer formation, does not have access to all available firn pore space.

Calculating groundwater mixing ratios in multi-aquifers based on statistical methods: a case study

Abstract Samples of river water and groundwater from Quaternary (QA), sandstone (SA), Taiyuan formation (TA), and Ordovician limestone (OA) aquifers in the Suxian coal-mining district, Anhui Province, China were collected. Their physicochemical properties, and major ion and isotopic compositions were determined. The samples were alkaline, with pH values exceeding 8, and the total dissolved solids concentrations depended on the water source. The δD and δ18O contents were highest in the river water samples and lowest in the SA groundwater. The isotopic characteristics of the QA and OA groundwaters suggest recharge by rainfall and surface water. The isotopic characteristics of river water were controlled mainly by evaporation. Water–rock interactions, the flow rate, and the main water sources were the most important influences on groundwaters in QA, OA, and TA, but the properties of SA groundwater were controlled by static reserves. Two discriminant functions, explaining more than 98.2% of the total variances, indicated that QA, TA, and OA were hydraulically connected. Three groundwater sources were identified as end-members, and a conceptual model was established to calculate water mixing ratios.

Pore resistivity variation by Resistivity imaging technique in sedimentary part of main Gadilam river basin, Cuddalore District, Tamil Nadu, India

Electrical resistivity is the only property of physics which give information of subsurface moisture content in the formation, Hence geophysical electrical resistivity survey was carried out to investigate the nature of shallow subsurface formations and geological contact in the main Gadilam river basin of Cuddalore District in Tamil Nadu. Twenty-seven vertical electrical soundings (VES) were conducted by Schlumberger configuration in the basin. Data is interpreted by curve matching techniques using IPI2 WIN software, layer parameters like apparent resistivity (?a) and thickness (h) interpretation were exported to Geographic Information System (GIS). Interpretation distinguishes three major geoelectric layers like topsoil, sandy clay layer, clayey sand layer along the contact zone in the basin. Interpreted VES sounding curves are mostly four-layer cases of QH, H, HA and KH type. Investigation demarcates lithology of subsurface and hydrogeological set up by employing maximum possible electrode sounding to infer saline water and freshwater occurrence based on resistivity signals. Zone of groundwater potential map was prepared with the combination of resistivity (?= ?1+ ?2+ ?3+ ?4) and corresponding thickness (T= T1+T2+T3+T4). High resistivity value of >200 ? m and low resistivity value of <10 ? m show the occurrence of alkaline and saline water within the formation aquifers as a result of possible rock water interaction and saline water dissolution. Four-layer resistivity cases from the matched curve (namely KH, AH, QA, and KA type) show the resistivity distribution/variation. It separates the freshwater depth wish from 1 to 140 ? m in fluvial sediments. Flood basin, sandstone and clay layer with low resistivity value of 3.16 - 7.5 ? m indicates contact with saline and freshwater aquifer. The Iso – resistivity map delineates saline water and freshwater zones with in the fourth layer cases in the same locations to indicate the irrational way of abstracting groundwater, resulting in saltwater ingress.

Assessing the Suffosion Risk for the Final in-Situ Slopes of the North Peşteana Open-Pit

Abstract With the occasion of complex and detailed studies, conducted especially from the geotechnical point of view (between 2016 and 2019), on the North Pesteana mining perimeter (more precisely on the lignite open-pit with the same name) numerous areas affected by suffosion were highlighted, mainly located on the lower steps (steps III and IV). Starting from these observations, the present paper analysis the risk of suffosion phenomenon to occur in the case of the final slopes of North Pesteana open-pit. In general, as observed, these areas have small and medium sizes, and do not affect significantly the stability of the steps, being immediately remedied with the advancement of the work front. Also, it was observed that, with the advancement of the excavation fronts, the groundwater currents constantly entrain the fine particles from the aquifer formations, and therefore new such suffosion areas occur. Taking into account the fact that the exploitation of lignite in this perimeter is ending soon, it was considered as necessary to assess the risk of suffosion at the final slopes (long term slopes) in order to be able to identify appropriate measures to prevent future potential catastrophic events.