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The Quaternary deposit in the Shanghai region is composed of a layered multi-aquifer-aquitard system (MAAS). The MAAS was formed mainly during the warm geological era over 2.6 million years ago. There is one artesian aquifer and five confined aquifer layers (AqI to AqV) in the MAAS with a very high groundwater pressure head. The groundwater in the aquifers of Shanghai is composed of both fresh and saline water due to it originating in different environmental conditions. AqI is the uppermost shallow confined aquifer, and it contains highly mineralised formation water with a wide variety of naturally occurring inorganic compounds. AqII and AqIII have slightly lower salinity and different hydrochemicals from those in AqI. The deeper aquifers, AqIV and AqV, have much lower levels of hydrochemicals. With the urbanisation of the Shanghai region, a large amount of underground infrastructure has been constructed in the shallow aquifers (AqI and AqII). As a result, the hydrochemicals in the groundwater present a potential hazard to this infrastructure. This paper reviews the hydrogeochemical compositions of aquifers in Shanghai and then discusses possible hazards to infrastructure construction within aquifers. In addition, this paper assesses the hydrogeochemical environment of the groundwater and the possibility of such environment-induced hazards arising in Shanghai.

The Niebla-Posadas (NP) aquifer in southern Spain is one of the main groundwater sources for the lower Guadalquivir Valley, a semiarid region supporting an important population, agriculture and industry. To contribute to the understanding of this aquifer the assessment of sustainable use of groundwater, the residence time of groundwater in the NP aquifer has been estimated using 3H, 14C and 36Cl. Along the flow paths, recharged groundwater mixes with NaCl-type waters and undergoes calcite dissolution and is further modified by cation exchange (Ca Na). Consequently, the water loses most of its calcium and the residual d13CDIC in the groundwater is isotopically enriched. Further modifications take place along the flow path in deeper zones, where depleted d13CDIC values are overprinted due to SO42 and iron oxide reduction, triggered by the presence of organic matter. Dating with 3H, 14C and 36Cl has allowed the differentiation of several zones: recharge zone (30 ky). An apparent link between the tectonic structure and the groundwater residence time zonation can be established. Regional faults clearly separates deep zone 1 from the distinctly older age (>30 ky) deep zone 2. From the estimated residence times, two groundwater areas of different behavior can be differentiated within the aquifer.

Groundwater is ubiquitous and immensely important for human uses but there is inadequate supply especially in the basement complex terrain as most boreholes are either abortive or can’t yield sustainable water to wells. This research tends to delineate into the subsurface in order to understand the aquifer pattern in Ogbagba area. A geophysical survey involving twelve vertical electrical sounding (VES) was carried out at some selected locations in Ogbagba. Resistivity meter was used to acquire the geophysical field data. Conventional partial curve matching and WinResist software was used for the data processing. 75% of the aquifers in the study area are confined aquifers while the remaining 25% are unconfined aquifers. Also, three probable aquifer units were delineated where clayey sand has 75%, sandy clay constitutes 16.7% and fractured bedrock shares the remaining 8.3%. The study revealed that insufficiency of groundwater exploitation in the study area is due to the geologic formation of the aquifers and the depth to which groundwater is been abstracted. If these mistakes are corrected, Ogbagba will henceforth start to enjoy groundwater exploitation adequately

Since 1963, radioactive waste has been injected in deep artesian aquifers of Cretaceous terrigenous deposits in western Siberia. It is well known that geologic heterogeneity strongly affects contaminant transport in unconsolidated formations. To predict the long-term migration of this radioactive waste the effective hydraulic and macrodispersion parameters are estimated by using a three-dimensional high-resolution hydraulic heterogeneity model. The heterogeneous model of the injection area is developed by applying transition probability geostatistics. This model is used to simulate local steady-state groundwater flow and advective transport, leading to numerical estimates of effective hydraulic conductivity and macrodispersion parameters. Mean seepage velocities and effective longitudinal macrodispersion are calculated from observed breakthrough curves for a conservative tracer. Results show that mean horizontal lengths exceed vertical lengths by a factor of more than 30. As a result, vertical effective hydraulic conductivity is two orders of magnitude less than the horizontal effective conductivity. Observed breakthrough curves exhibit long tails and appear to be non-Fickian. Estimated effective longitudinal macrodispersivity in the vertical direction is one order of magnitude less than that in the horizontal direction. Under a Fickian framework, this implies that dispersion modeling for regional transport simulations requires an anisotropic-media dispersion model.

This paper presents an investigation into increased deformation of Aquifer II caused by groundwater pumping from the aquifer in Changzhou, China. As groundwater levels of aquifers have been decreasing in recent decades due to uncontrolled water pumping, land subsidence is becoming a serious geohazard in Changzhou. Based on recently reported field data, the compression of aquitards has not increased compared to that of aquifers with the same scale of layer thickness. The Cosserat continuum model was adopted to analyse the observed phenomenon in this study. A classic Cauchy continuum model is also used for comparison. The comparison between these two models indicates that the proposed approach can interpret the increased deformation well, and the classic Cauchy continuum model underestimates the aquifer deformation as it does not consider shear displacement and macro-rotation. A discussion on the relationship between the groundwater level in the aquifer and subsidence is then undertaken. The results show that the severity of the annual subsidence is correlated with the variation in groundwater level in Aquifer II. To mitigate the subsidence hazards, countermeasures should be adopted to avoid the shear stress in aquifers which results from the high hydraulic gradient, by the appropriate allocation of pumping wells and by restricting groundwater withdrawal volume from each pumping operation.

Storm-water harvesting and storage via managed aquifer recharge (MAR) is a promising approach to combat water scarcity in semi-arid regions, but poses a challenge for karst aquifers and regions with highly variable water availability. The infiltration of low-mineralized surface water and its impact on highly mineralized groundwater of a karst aquifer was investigated at Wala reservoir in Jordan over a period of approximately 10 years. The results show significant groundwater-level rise in a wellfield, in response to the yearly average infiltration of about 6.7 million m3. This corresponds to about 60 % of the yearly average abstraction of about 11.7 million m3, confirmed by mixing calculations with tritium. A decreasing trend in infiltration due to sedimentation is observed. Mean groundwater residence times of several thousand years, derived from carbon-14 dating, indicate a large storage capacity of the aquifer. The heterogeneous distribution of the residence times is caused by strong groundwater withdrawals and artificial recharge along with karst-specific aquifer characteristics. Temporal groundwater salinity fluctuations in the wellfield are observed after the first MAR infiltration. Enhanced groundwater flow along the wadi course was demonstrated, which is an important aspect with regards to future MAR projects in similar wadis of the region.

Purpose – The quality of groundwater in the vicinity of petroleum products retailing stations in Ile-Ife, Nigeria was investigated with a view to providing valuable information on the organic and other physico-chemical parameters associated with the contamination of the groundwaters by petroleum products. The paper aims to discuss these issues. Design/methodology/approach – Three sets of samples were collected per season from artesian wells within petroleum products retailing stations for polycyclic aromatic hydrocarbons (PAHs), trace metals and other physico-chemical parameters analysis. Extraction, cleaned-up and concentration of the PAHs were done using certified analytical methods. Levels of the PAHs and metals were determined using gas chromatography coupled with flame ionization detector and bulk scientific atomic absorption spectrophotometer, respectively, while other pollution indicators were measured using standard analytical procedures. Findings – The groundwaters contained elevated levels of PAHs, Cu, Zn, Mn, Pb, Cr, V, Ni, Fe and total dissolved solids than their maximum allowable limits for drinking water. Analysis of variance (ANOVA) results confirmed that both seasonal variation and location had much influence on the levels of most of the analyzed parameters. Some of the parameters showed strong positive correlation with each other, while Cr/Pb and Na/Pb displayed strong negative correlation with each other, indicating similar source(s) and/or chemical affinity and vice versa, respectively. Cross-plot analysis results using metals and PAHs concentrations as variables showed significant positive correlations (R2=0.99) and (R2=0.60), respectively, suggesting similar source(s) of contamination of the two sets of samples. Originality/value – The level of the groundwater contamination was an indication of indiscriminate discharge of petroleum products and/or underground tank leakage within the study areas.

Summary This paper presents an analytical solution generated by linearizing the one-dimensional non-linear Boussinesq equation to characterize the variation of groundwater level induced by tidal waves and rainfall in a coastal unconfined sloping aquifer. The area of the coastal aquifer is divided into 2 zones – the coastal zone of rainfall and the inland zone of non-rainfall. The derivation of the solution is based on the Dupuit–Forchheimer assumptions of a wide range of problems in unconfined groundwater flow and the analytical solutions of coastal and inland water tables of both zones are obtained. The results indicate that the effects of the bottom slope of the aquifer and the beach slope on the groundwater fluctuation are substantial in the unconfined aquifer. Large rainfall intensity with tidal waves will enhance the fluctuation significantly, but less effect on the fluctuation is found for the cases of steeper sloping bottom under the same rainfall condition.

Groundwater is globally important for human consumption, and changes in quality can have serious consequences. The study area is within a coastal aquifer where groundwater quality is influenced by various potential sources of salinity that determine the composition of water extracted from wells. Groundwater chemistry data from the aquifer have been acquired to determine the geochemical conditions and processes that occur in this area and assess their implications for aquifer susceptibility. Analysis of groundwater samples shows that the dominant watertype is mostly NaCl with pH < 7 in both aquifers (i.e. upper and lower) except for the shallow wells where CaHCO3 prevails with pH ⩾ 7, and boreholes located near the Indian Ocean, where coral reef limestone deposits are located and the watertype evolves towards CaHCO3. In the lower aquifer, Cl− is higher than in the upper aquifer. The origin of salinity in the area is strongly influenced by groundwater ascending from deep marine Miocene Spatangid Shales through faults, seawater incursion on the border of the Indian Ocean, and throughout, there is some salinity within the Quaternary aquifer, especially in intercalated deltaic clays in the fluviatile deposits, showing some marine influences. The seawater intrusion is linked to the strongly increasing groundwater exploitation since 1997. Another process that plays a major role to the concentration of major ions in the groundwater is calcite dissolution. Next to geogenic salinity and seawater intrusion, anthropogenic pollution as well is affecting groundwater quality in the aquifer. An important result of this study is the observation of high nitrate concentrations, that call for improved sanitation in the area, where domestic sewage with on-site sanitation (mainly pit latrines) also threatens the groundwater resource.

Achieving high recovery efficiency is a goal for almost all aquifer storage recovery (ASR) wells, whether storing fresh water in brackish aquifers or in fresh aquifers containing native water quality constituents that are not wanted in the recovered water. This goal can be achieved rapidly by initial formation and maintenance of a target storage volume (TSV) that includes the water volume required for recovery plus a buffer zone volume that separates the stored water from the surrounding native groundwater. The buffer zone volume is a one-time addition of water to the well. An ASR demonstration project was constructed and tested at Hilton Head Island, South Carolina, USA, storing drinking water in a brackish limestone, semi-confined, artesian aquifer. Operating performance has confirmed the viability of this TSV approach for development of ASR wells. The stored drinking water was recovered at a flow rate of 8 Ml/D for 126 days, with an ending chloride concentration of 170 mg/l, rapidly achieving 100 % recovery efficiency. The storage aquifer had a chloride concentration of 685 mg/l. Results have since been replicated at two other ASR wells on Hilton Head Island, addressing the expected loss of all remaining fresh public water supply wells on the island due to saltwater intrusion. ASR well cycle testing in which the same volume is stored and recovered, with progressively larger storage volumes in each successive cycle, is appropriate for geochemical and microbial studies but is inappropriate for determination of recovery efficiency since any buffer zone is removed during each cycle.

Understanding water exchange between streams and groundwater, or surface water-groundwater interactions, is of primary importance for solving conflicts related to water use and for restoring water ecosystems. The main goal of this study was to demonstrate that combination of classic geochemical tools and isotopic tools (δ2H and δ18O of water, δ34SSO4 and δ18OSO4 of sulfates, 87Sr/86Sr) can lead to a better understanding of surface water - groundwater interactions for a main alluvial aquifer in the Alpes mountains (Isère River alluvial aquifer) used for drinking water supply. We report here the results that identified 3 aquifer units based on groundwater recharge.

The Ogallala-High Plains aquifer is an important resource for irrigated agriculture in a semi-arid region of the United States. Steep declines in groundwater levels are putting increasing strain on the viability of the aquifer for irrigation, necessitating improved estimates of recharge rates and sources to the aquifer. This study uses a combined approach to obtain high resolution geochemical and isotopic composition of the vadose zone and aquifer pore fluids to better understand recharge dynamics to the aquifer. Significant differences between the shallow, intermediate and deep vadose zone and shallow and deep aquifer indicate modern precipitation is not providing a significant source of recharge to the aquifer across a large area (diffuse recharge). Rather, recharge to the aquifer is a result of either focused recharge or long-term, delayed drainage from the portion of the vadose zone which was saturated before irrigation development.

The first part of this work is dedicated to the response of different-age structures to lunisolar tides, which can be considered as a sounding signal for monitoring the state of fluid-saturated reservoirs. The complex approach to processing the data obtained at the testing sites of the Institute of Geosphere Dynamics of the Russian Academy of Sciences, Institute of Geophysics of the National Academy of Sciences of Ukraine, and KIEV station of the IRIS seismic network is applied for recognizing the tides against the hydrogeological, barometric, and seismic series. The comparative analysis of the experimental and theoretical values of the diurnal and semidiurnal tidal components in the time series of ground displacements is carried out. The tidal variations in the groundwater level are compared with the tidal components revealed in the ground displacement of the different-age structure of the Moscow Basin and Ukrainian Shield, which are parts of the East European artesian region. The differences in the tidal responses of the groundwater level and ground displacement probably suggest that the state of the massif is affected by certain additional factors associated, e.g., with the passage of earthquake-induced seismic waves and the changes in the hydrogeodynamic environment.

The groundwater geochemistry of Lower Kelantan Basin was evaluated based on major ions characteristic to determine its suitability for drinking, domestic use and irrigation. Groundwater samples from different aquifer layers (shallow, intermediate and deep) were collected and analysed for pH, electrical conductivity (EC), total dissolved solid (TDS), Ca, Mg, Na, K, Cl, SO4, CO3, HCO3, NO3, Fe and Mn. The results show that the shallow groundwater is dominated by Ca-HCO3 and Na-HCO3 while intermediate is dominated by Na-Cl and Na-HCO3, and deep aquifer by Na-HCO3 water facies. The sodium adsorption ratio (SAR) and salinity hazard indicate that the groundwater from shallow and deep aquifer is suitable for irrigation purposes, and part of intermediate aquifer is not suitable for crop irrigation. Groundwater from shallow and deep aquifer is regarded as fresh water and suitable for drinking, domestic and agricultural irrigation use while groundwater from intermediate aquifer is slightly brackish water particularly closed to coastal area.

In this study, we have analyzed the characteristics of deep aquifers that belong to hydrogeological area of Morava region, that is a part of Smederevo Danube region. Hydrogeological complex of Smederevo Danube region was developed in the sediments originated in Neogene. We have observed alternative rotations of hydrogeological collectors, composed of sandy and gravel sediments and hydrogeological insulatorsthat make clay creations. Based on the analysis of geological research, geophysical exploration and drilling for the need of water supply, we have tried to present a spatial position of the collectors, and dense aquifers formed in them. Mapping the dispersion of collectors and evaluating the yield of deep aquifers, it is possible to ascertain the possible usage of water under pressure. Aquifer under pressure is of sub-artesian and artesian character with the level of groundwater from +0.6 to -90 m. Exploitation yield of objects ranges over 5 l/s. Chemical analysis of groundwater from Pontic water-bearing sands, according to Alekin, shows that it belongs to the hydrocarbon-alkaline earth types of water whose mineralization is around 0.5 g/l. This means that this water is moderately hard and that it can be used for drinking. The waters of Pannonian layers belong to soft water, and in the deeper parts there is a possibility of increased mineralization.

Within the framework of precursor events related to earthquakes, this paper analyzes the possible effect on the aquatic environment of the surrounding energy that accompanies earthquakes, particularly in the area where oceanic and continental plates collide (Cocos Plate and North American Plate, south of Mexico). As a preamble, the types of precursor events, characteristics, and their possible origin are described. A project was designed under the assumption that in areas with high frequency and intensity seismicity there is an electrical and electromagnetic potential promoter which is detectable and assessable indirectly by measuring water conductivity behavior, which also may have atypical variations of data; the outcome of intensive conductivity monitoring in different settings, natural as well as manmade (wellsprings, artesian well and a cistern), are presented herein. The results of the conductivity monitoring for seven months, highlight two patterns in data behavior: one pattern shows the subtle dependence of data behavior on the geographic location of data monitoring instruments, revealing that could have a slight relationship between areas with increased seismic frequency and intensity and the presence of atypical conductivity variations. Another pattern reveals the possible relationship between atypical variations in conductivity and subsequent earthquake events; a total of 241 seismic events were analyzed and 59 of them are provided as evidence related with patterns mentioned.

Hydro-(major and trace elements: Cd, F and Sr), isotope (18O, 2H, 3H and 13C) geochemistry and radiogenic carbon (14C) of dissolved inorganic carbon (DIC) were used to investigate the sources of groundwater contamination and the hydrodynamic functioning of the multilayer aquifer system in the mining Gafsa basin (Southwestern Tunisia). The groundwater of the study area is subject to intense exploitation to accommodate all the water demands of this arid area. The Gafsa basin contains a multi-layered aquifer with four principal levels: Upper Zebbag (Cenomanian–Turonian), Abiod (Campanien–Maastrichian), Beglia (Miocene) and Segui (Plio–Quaternary) Formations. The hydrogeology of this system is largely affected by tectonics (Gafsa–Tebessa, Sehib, Negrine–Tozeur, Tabeddit and Metlaoui faults…). The groundwater of these aquifers undergoes a significant decline in water level (≈0.5 m y−1), increasing salinity (TDS increase from 400 to 800–6000 mg l−1: generally, TDS increases from the mountainous regions towards the discharge area) due to a long time of aridity, irregular rainfall and overexploitation (irrigation and industrial activities). Groundwater pumped from the semi-confined Complex Terminal (C.T) aquifers (Cretaceous and Mio-Plio-Quaternary: MPQ) and from the confined Continental Intercalaire (C.I) aquifers is an important production factor in irrigated oases agriculture and phosphate washing in Southwestern Tunisia. A rise in the groundwater salinity has been observed as a consequence of increasing abstraction from the aquifer during the last few decades. The salinization phenomena in the region are complex. Several possible causes for salinization exist: (1) the upwelling of saline and “fossil” water from the underlying, confined “C.I” aquifer; (2) as well as the backflow of agricultural drainage water; (3) phosphate and domestic wastewater; (4) brine intrusion from the salt lake (Sebkha/Garaat); (5) evaporate meteoric water dams (El Khangua and El Oudei); (6) reduced rainfall and (7) land and air alterations. The istopic study of waters establishes that the deep groundwater is “fossil” water (6000–37,000 years) recharged probably during the late Pleistocene and the early Holocene periods. The relatively recent water in the MPQ aquifer is composed of mixed waters resulting presumably from upward leakage from the deeper groundwater.

In article we present the experimental results on demanganation of well water where the manganese concentration exceeds 5 mg/L and iron concentration 20 mg/L. The developed technology for demanganation is described. The results of experiments at water treatment plant of Komsomolsk-on-Amur are presented.

The Janah alluvial aquifer is located in southern Iran with an arid climate. The type of groundwater in this aquifer is dominantly of sodium chloride and total dissolved solid of groundwater samples range from 1.63 to 335 g/L which confirms that groundwater quality has been severely degraded by salinization. Hydrogeochemical and isotopic investigations were conducted to identify the source of salinity. Total dissolved solids and major ion concentrations were measured at 51 selected sampling sites including springs, wells and surface waters. In addition stable isotopic composition (oxygen-18 and deuterium) was measured in 6 sampling points. The study indicates that the sources of salinity of the Janah aquifer include dissolution of salt diapir and evaporite rocks, a geothermal spring and intrusion of the river water which function individually or together in different parts of the aquifer. Based on the hydrogeochemical and geological studies conceptual flow models were prepared for different parts of the aquifer which illustrate how each source of salinity deteriorates the quality of the alluvial aquifer. We proposed few remediation methods including construction of cemented channel and sealed basins to improve groundwater quality. These methods would prevent infiltration of low quality water into the alluvial aquifer.

The CO2 bubble volume fraction, eruption velocity, flash depth and mass emission of CO2 were determined from multiple wellbore CO2-driven cold-water geysers (Crystal and Tenmile geysers, in Utah and Chimayo geyser in New Mexico). At shallow depths the bubble volume fraction ranges from 0 to 0.8, eruption velocities range from 2 to 20 m/s and flash depths are predominately shallow ranging from 5 to 40 m below the surface. Annual emission of CO2 is estimated to be ( 4.77 ± 1.92 ) × 10 3 , ( 6.17 ± 1.73 ) × 10 1 , ( 6.54 ± 0.57 ) × 10 1 t/yr for Crystal, Tenmile and Chimayo geysers, respectively. These estimates are coherent with Burnside et al. (2013) showing that the rate of CO2 leakage from wellbores is greater than fault-parallel or diffuse CO2 leakage. The geyser plumbing geometry consists of a vertical wellbore which allows for the upward migration of CO2-rich fluids due to artesian conditions. The positive feedback system of a CO2-driven eruption occurs within the well. Active inflow of CO2 into the regional aquifers through faulted bedrock allows geysering to persist for decades. Crystal geyser erupts for over 24 h at a time, highlighting the potential for a wellbore in a natural environment to reach relatively steady-state high velocity discharge. Mitigating high velocity CO2-driven discharge from wellbores will, however, be easier than mitigating diffuse leakage from faults or into groundwater systems.

The impact of climate change and Baltic Sea level rise on groundwater resources in a shallow, unconfined, low-lying coastal aquifer in Hanko, southern Finland, was assessed using the UZF1 model package coupled with the three-dimensional groundwater flow model MODFLOW to simulate flow from the unsaturated zone through the aquifer. The snow and PET models were used to calculate the surface water availability for infiltration from the precipitation data used in UZF1. Infiltration rate, flow in the unsaturated zone and groundwater recharge were then simulated using UZF1. The simulation data from climate and sea level rise scenarios were compared with present data. The results indicated changes in recharge pattern during 2071–2100, with recharge occurring earlier in winter and early spring. The seasonal impacts of climate change on groundwater recharge were more significant, with surface overflow resulting in flooding during winter and early spring and drought during summer. Rising sea level would cause some parts of the aquifer to be under sea level, compromising groundwater quality due to intrusion of sea water. This, together with increased groundwater recharge, would raise groundwater levels and consequently contribute more surface leakage and potential flooding in the low-lying aquifer.

Parameter estimates of artesian aquifers where piezometric head is above ground level are largely made through free-flowing and recovery tests. The straight-line method proposed by Jacob-Lohman is often used for interpretation of flow rate measured at flowing artesian boreholes. However, the approach fails to interpret the free-flowing test data from two artesian boreholes in the fractured-rock aquifer in Table Mountain Group (TMG) of South Africa. The diagnostic plot method using the reciprocal rate derivative is adapted to evaluate the artesian aquifer properties. The variation of the derivative helps not only identify flow regimes and discern the boundary conditions, but also facilitates conceptualization of the aquifer system and selection of an appropriate model for data interpretation later on. Test data from two free-flowing tests conducted in different sites in TMG are analysed using the diagnostic plot method. Based on the results, conceptual models and appropriate approaches are developed to evaluate the aquifer properties. The advantages and limitations of using the diagnostic plot method on free-flowing test data are discussed.

It is revealed that the Altyn-Emel mud volcanic field (43°52′56″ N, 79°06′31″ E) in the Yli depression (Dzharkent trough) is structurally linked to the northeastern end of the Chilik-Kemin deep fault. The mud volcano is related to hydrocarbon-rich gases (including methane) and pressure artesian mineralized thermal waters, which uplifted to the surface along the fault zone. It is suggested that the earthquakes with M≤ 5 related both to the Chilik-Kemin fault and other seismic generating structures intensified the mud volcanic activity. In some cases, the eruptions were accompanied by the short-lived ignition of hydrocarbon gases and formation of the Na-rich paralavas. The mud volcanism of the Altyn-Emel field has been manifested during the last 15–20 k.a., and, consequently, the northeastern part of the Chilik-Kemin fault is an active structure.

Study region The Galilee and Eromanga basins are located in central Queensland, Australia. Both basins are components of the Great Artesian Basin which host some of the most significant groundwater resources in Australia. Study focus This study evaluates the influence of regional faults on groundwater flow in an aquifer/aquitard interbedded succession that form one of the largest Artesian Basins in the world. In order to assess the significance of regional faults as potential barriers or conduits to groundwater flow, vertical displacements of the major aquifers and aquitards were studied at each major fault and the general hydraulic relationship of units that are juxtaposed by the faults were considered. A three-dimensional (3D) geological model of the Galilee and Eromanga basins was developed based on integration of well log data, seismic surfaces, surface geology and elevation data. Geological structures were mapped in detail and major faults were characterised. New hydrological insights for the region Major faults that have been described in previous studies have been confirmed within the 3D geological model domain and a preliminary assessment of their hydraulic significance has been conducted. Previously unknown faults such as the Thomson River Fault (herein named) have also been identified in this study.

The forecast for climatic change effects over groundwater requires to know the modifications that are going to take place (i.e. variations in temperature and precipitation) but also to determine if aquifers are under stable conditions. The alteration of the natural systems due to anthropogenic activities during the last decades can change aquifer recharge sources and lead to a transition towards new future steady state conditions. The Motril-Salobrena aquifer has undergone a rapid coastline progradation over the last 500 years. The sediments provided by the Guadalfeo River generated new land that was totally covered by the sea due to the colonization of Sierra Nevada and the intense deforestation of areas with high slopes and elevated runoff. The erosion and transport of sediments to the sea produced a coastline advance of over 3 m year−1. The location of the sea border is one of the mayor controller of the salinity distribution in coastal aquifers. The effect of the coast progradation over salinity distribution and the flushing time by freshwater have been explored with a paleo-hydrogeological model simulating the transient evolution of the groundwater salinity over the last 6000 years. A sedimentological study of the aquifer was carried out based on the lithological columns considering the depositional systems in coastal areas to define the aquifer properties. The results of the model provide variable saltwater flushing times from decades to hundreds of years indicating that the aquifer can be considered currently in equilibrium with punctual exceptions and it can be easily affected by future changes.

Rock water interactions play an important role in the flow of groundwater. Groundwater samples were collected from deep production wells with depths ranging from 120 to 230 m. Complete chemical analysis of 40 groundwater samples was collected from the fractured limestone aquifer including major cations (Na+, K+, Ca2+, Mg2+) and major anions (Cl−, SO4 2−, HCO3 −, CO3 2−). A geochemical modeling (NETPATH Software) was applied for environmental simulate net geochemical mass-balance reactions between initial and final waters along a hydrologic flow path. This program simulates selected evolutionary waters for every possible combination of the plausible phases that account for the composition of a selected set of chemical constraints in the system. The groundwater of the Eocene aquifer mainly belongs to fairly fresh water with salinity contents ranging from 228 to 3595 ppm. The measured groundwater levels range between 8 and 25 m near the river Nile to the limestone plateau (eastwards). Consequently, groundwater flows from east to westward toward the river Nile. Groundwater aquifer in the study area is mainly composed of fractured limestone; the saturated states of the PCO2, calcite, aragonite, dolomite, siderite, gypsum, anhydrite, hematite, and goethite in addition to H2 gas were estimated. The undersaturated state of carbon dioxide reflects closed conditions and very low probability of recent recharge, and it reveals also the high tendency of water to precipitates carbonate species. Undersaturation by carbonate minerals is only restricted to some pockets distributed on the different places of the aquifer in the study area. The majority of groundwater samples of Eocene aquifer in the study area indicated that groundwater is not suitable for irrigation with treatment and requires good drainage.

авторами рассмотрены системы очистки, наиболее активно использующиеся для очистки подземных артезианских вод, такие как «Гейзер», «Гейзер – 1», комплексная система, состоящая из ионообменного фильтра Aquadean-PRO и газоразрядной установки, а также система бактерицидного обеззараживания. Был также проведен сравнительный анализ воды на тяжелые металлы до и после системы очистки с помощью прибора МАП – 1 и эксперименты по определению железа фотометрическим методом. Показано, что наиболее эффективной из систем очистки воды является комбинированная система, которая состоит из ионообменного фильтра и электроразрядной установки с применением лавиностримерного разряда.

The Ant Miner algorithm was compared with the bivariate frequency ratio (FR) and boosted regression trees (BRT) algorithms in terms of its capacity to assess groundwater potential. A geospatial dataset was prepared that contains two components: a flowing well inventory map and eleven factors relevant to groundwater conditions. Average nearest neighbor technique was used to investigate the spatial pattern of flowing wells and to find the appropriate distance between flowing and nonflowing points in the study area. A wrapper approach known as random forest classifier and a filtering approach known as information gain ratio were used to identify the most relevant groundwater factors. The developed models were validated via the area under the operating characteristic curve. Results revealed that the Ant Miner model performed better in terms of both success (0.944) and prediction (0.92) rates compared to FR and BRT. Furthermore, the Ant Miner algorithm derived five simple, easily interpreted rules for predicting groundwater potential that can be used by hydrogeologists for identifying potential groundwater well locations with minimal effort and cost.

Water management is one of the most challenges in Algeria, a semi-arid Mediterranean country confronted to a serious water stress. The country will have to endure, beyond 2025, a situation of chronic water penury, adding an excessive pollution of the majority of groundwater reservoirs. The management of water resources by combined approach using hydrogeological model and nitrates evolution model was experimented in the Middle Soummam valley. The alluvial aquifer, offering good hydrodynamic and geometrical characteristics, is over-exploited, providing in drinking water Akbou and Tazmalt cities and irrigation perimeters. If exploitation continues at these steady paces, the depletion of the water resource and the hydrochemical imbalance will be inevitable. On the one hand, the results of hydrodynamic model, based on an increase of the water takings and simulated needs from 24.71 Mm3/year in 2015 into 39.69 Mm3/year in 2030, show a critical withdrawal. The aquifer budget expresses the inversion of flow between the wadi and the aquifer where the wadi feeds the groundwater reservoir. This hydrodynamic inversion was attributed to simulated pumping rates which increased and exceeded 100,000 m3/day, but the aquifer was partially relieved by the weight of the exploitation through Tichy Haf dam. The water management strategy adopted in this study was based on management measures promoting zones, which have been delimited between Tazmalt and Akbou, and containing important water quantities available in the axis of the valley. However, according to the depleted in isotopes of 18O and 2H, which could be explained by the influence of a paleoclimatic effect and suggested that the aquifer recharge would have largely been made under a colder climate, pumped groundwater could be old, and the implementation of new pumping sites has been studied minutely. On the other hand, the hydrogeochemical modelling allowed following nitrates concentrations in order to project their evolution. Four wells on 25 react in face to the imposed conditions in each scenario simulated until 2030, showing inertia of pollution, and confirmed after three series of tests. This inertia would be related to the hydraulic gradients and hydraulic conductivities, aquifer thickness and recharge. The low hydraulic gradients lead to a rather slow flow velocity and thus to an inertia in the dispersion of nitrates, with a mass transport weakened by the hydrodynamic conditions. It is also related to the aquifer thickness; when the aquifer is powerful (65–85 m), the stock of water would be important and allows a dilution process. The reverse is true for the simulated boreholes where the concentrations remain invariant; the aquifer is less powerful (32–37 m). Finally, the recharge effect through the rain was evoked; the aquifer is unconfined, and the rain water and pollution that reached the piezometric level can remain in position in slow hydrodynamic conditions. The methodology was demonstrated through a combination of monitoring and modelling for both water quantity and quality and the importance to use numerical models to support water resources management strategy in the Mediterranean aquifers.

Elements of surface atmospheric electricity have never been used to solve problems of applied geophysics. A physical model representation of hydrogen, methane, radon, and elements of surface atmospheric electricity is constructed. Bubble formations of volatile gases capture from the depth of 4–6 m soil radon and carry it into the near-surface layers of the soil and atmosphere. The increase in the density of carrier gases over the ore body, oil field, fault zones, karst cavities leads to a fall in the atmospheric electric field and an increase in the polar air conductivities. The pumping of artesian water causes an increase in the atmospheric electric field. The injection of fluid into the ground leads to the reverse process—the fall of the atmospheric electric field.

Foundation dewatering has become a major cause of land subsidence in Shanghai. The burial depth of foundations in relation to geotechnical construction works is less than 75 m, and the corresponding groundwater includes phreatic, low-pressure artesian, and the first confined aquifers. Based on the geological and hydrogeological conditions beneath Shanghai, methods of dewatering may be divided into three modes and further five patterns according to the insertion depth of the dewatering-retaining system. The most common dewatering mode aims to reduce the water pressure in the confined aquifer by setting the dewatering wells inside the pit, whilst the retaining walls are buried in the confined aquifer and partially cut off the confined aquifer layer. To predict the settlement due to foundation dewatering, numerical models are generally adopted, which are similar to those used to predict land subsidence induced by regional groundwater withdrawal; however, since foundation dewatering is conducted along with the setting of retaining walls and foundation pit excavation, which differs from regional groundwater withdrawal, interactions between the retaining wall-dewatering well, the dewatering-excavation, and dewatering-recharge are important factors affecting the analytical model. Since the grading of the shallow soil layers is different, stratified settlement characteristics of the shallow soil strata and seepage erosion, which results in additional deformation, need to be given particular consideration.

The deep wells drilled along the eastern escarpment of the Jordan Valley penetrate confined aquifers that produce thermal and mineralized artesian water. Uncontrolled flows from poorly constructed and uncapped artesian wells over the last 30 years have caused the deterioration of the quality of shallow groundwater and surface water. They also have been accelerating the discharge of saline water from deep aquifers and have caused the loss of shallow fresh groundwater resources through the downward percolation of fresh water to replace the extracted deep salty groundwater. A lack of adequate controls on the construction and maintenance of artesian wells is leading to widespread water quality problems in the region, which limits the ability of future generations to access high-quality water, a clear breach of the principle of intergenerational equity.

Major ions and important trace elements in addition to δ18O and δ2H were analysed for 43 groundwater samples sampled from the Al-Batin alluvial fan aquifer, South Iraq. The most dominant ions (with respect to molarity) were: Na+ > Cl− > SO4 2− > Ca2+ > Mg2+ > NO3 − > HCO3 −, with total dissolved solids (TDS) averaging 7855 mg/L. High concentrations were found for the trace elements U, Mo, V, B, Sr, and Cr. This study suggests a hydraulic connection exists near the fan apex between the uppermost part of the Al-Batin aquifer and the underlying Dammam aquifer by means of the Abu-Jir fault system. Except for the effects of extensive irrigation, fertilizer use, and poorly maintained sewers, the groundwater chemistry is mainly controlled by geological processes such as dissolution of evaporites and the enrichment of dissolved ions as a result of the high evaporation and low recharge rate. Furthermore, it is shown that the Kuwaiti fuel–oil burning during Gulf War in 1991 contributed to the enrichment of V and Mo in the studied aquifer. The spatial distribution of most ions appears to generally increase from the south-west towards the north-east, in the direction of groundwater flow. The stable isotopes show heavier values in groundwater with a gradually increasing trend in the direction of groundwater flow due to the decreasing depth to groundwater and thus increasing of evaporation from both groundwater or irrigation return water. Additionally, the stable isotope signature suggests that rainfall from sources in the Arabian Gulf and the Arabian Sea is the major source of recharge for the Al-Batin aquifer. Except for two samples of groundwater, all samples were not suitable for potable use according to the WHO standards. Most of the groundwater is suitable for some agricultural purpose and for livestock water supply. Apart from the high salinity, boron represents the most critical element in the groundwater with respect to agricultural purposes.

The Northeast Groundwater Management Area of Wisconsin, USA contains two major cones of depression in a confined sandstone aquifer. Each cone is centered near cities that have used groundwater for over 100 years. Near one of these cities (Green Bay), episodic changes in the development of groundwater and surface water resources during this period have resulted in major changes to the potentiometric surface. On two occasions, roughly 50 years apart, reductions in groundwater withdrawals have resulted from the construction of pipelines drawing surface water from Lake Michigan. In each case, rapid recovery of the potentiometric surface by as much as 70 m has occurred in the northern of the two pumping cones. The most recent switch occurred during 2006 and 2007 when eight communities stopped pumping groundwater, reducing daily withdrawals by approximately 46.37 million liters. The rate of water level recovery has diminished in some areas, with a return to a flowing artesian state for some municipal and residential wells. Although the northern portion of the groundwater management area has returned to a sustainable condition in the confined aquifer, the portion with the southern cone of depression remains in a state of prolonged drawdown.

In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysis of the dissolved constituents reveals that groundwater evolves from fresh water (TDS =300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO 3⋅Cl–Na ⋅Mg to HCO 3⋅Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water and glacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (3H and 14C) isotope data, range from present to Holocene (∼28 ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow direction is turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.

One hundred and forty species of birds have been credibly recognised (during 1970–1990) as Kyzyl Kum desert inhabitants. They are distributed in seven arid landscapes that are unequal in edaphic and floristic characteristics. The most environmentally capacious landscape is the spates of artesian lakes and banks with grass–shrub complexes, where 83 bird species were found. The valleys of dry riverbeds occupied with tamarisk saxaul groves contained 56 bird species. The smallest species range (16) was observed in the variations of the takyr spaces with poor vegetation. This paper also outlines the relative abundance of 40 species of birds that are typical inhabitants of desert landscapes. We studied four of their habitats, and the effects of seasonal changes on the species composition of shorebirds in three artesian lakes were determined.

The Blue Nile (Abay) River is originating in the Lake Tana basin where many perennial and seasonal streams feed the largest lake of Ethiopia (Tana). The basin is characterized by different volcanic formations covered by thick alluvial and residual Quaternary sediments at the center of the basin around Lake Tana. In this study, an attempt was made to outline the hydrogeology of the basin based on limited information from well lithologic logs and previous relevant works. The Lake Tana basin is considered as a potential area for surface water and groundwater development corridors. The hydrogeology and groundwater occurrence is complex due to tectonism and existence of different volcanic rocks covered with thick alluvial sediments at the center of the basin. The shallow aquifer systems in the middle of the basin from the alluvial sediments are tapped by local communities using shallow wells fitted with hand pumps. The volcanic aquifers are multi-layer and tapped from different volcanic layers. The latter are highly productive depending up on the degree of fracturing and weathering. In few cases, as in the case of Kola Diba area there are artesian wells. The groundwater system converges towards the center of the basin. The Lake Tana basin leaks groundwater to the adjacent Beles basin and through the Blue Nile outlet.

The Balcones Fault Zone segment of the Edwards Aquifer of south-central Texas is one of the most important and prolific karst aquifers in the United States. It is formed within the lower Cretaceous Edwards Group Limestone. Since deposition, it has undergone subaerial exposure, burial in the upper Cretaceous, faulting, igneous intrusion, uplift in the Miocene, and weathering processes. The Balcones Fault Zone consists of mostly normal en-echelon faults with as much as 300 m of displacement striking northeast–southwest and dipping down toward the Gulf of Mexico. It forms the Contributing, Recharge, and Artesian zones of the aquifer. Karst characteristics of the Edwards Aquifer are the result of both epigene and hypogene processes, which continue today. The subaerial exposure of the Edwards Limestone (Recharge Zone) contains epigene karst features typical of a karst landscape that contains remnants of relict hypogene processes. Many relict caves in the Edwards Limestone outcrop show evidence of being formed by ascending water. Some appear to be associated with paleo-springs that were abandoned as water levels in the aquifer declined. Evidence of current hypogene processes is found in the saline water zone, which is part of the Artesian Zone. Extremely high permeabilities have been developed by dissolution at depth and driven by a number of processes including artesian hydraulic heads, mixing corrosion, and biogenic acids. As a result, well production in the Artesian Zone is commonly limited only by the size of the pump.

Worldwide, coastal aquifers are threatened by seawater intrusion. The threat is greatest when aquifers are overexploited or when recharge is low due to a semi-arid or arid climate. The Kaluvelli-Pondicherry sedimentary basin in Tamil Nadu (India) presents both these characteristics. Groundwater levels in the Vanur aquifer can reach 50 m below sea level at less than 20 km inland. This groundwater depletion is due to an exponential increase in extraction for irrigation over 35 years. No seawater intrusion has yet been detected, but a sulphate-rich mineralization is observed, the result of upward vertical leakage from the underlying Ramanathapuram aquifer. To characterize the mechanisms involved, and to facilitate effective water management, hydrogeological numerical modelling of this multi-layered system has been conducted. Existing and acquired geological and hydrodynamic data have been applied to a quasi-3D hydrogeological model, NEWSAM. Recharge had been previously quantified through the inter-comparison of hydrological models, based on climatological and surface-flow field measurements. Sensitivity tests on parameters and boundary conditions associated with the sea were performed. The resulting water balances for each aquifer led to hypotheses of (1) an offshore fresh groundwater stock, and (2) a reversal and increase of the upward leakage from the Ramanathapuram aquifer, thus corroborating the hypothesis proposed to explain geochemical results of the previous study, and denying a seawater intrusion. Palaeo-climate review supports the existence of favourable hydro-climatological conditions to replenish an offshore groundwater stock of the Vanur aquifer in the past. The extent of this fresh groundwater stock was calculated using the Kooi and Groen method. http://link.springer.com/article/10.1007/s10040-017-1558-4

This chapter describes the Ordinskaya Cave in the Fore-Urals region, Russia, which is the largest underwater cave of sulfate rocks in the world. The explored length of the cave is about 4900 m. The regional distribution of karst features indicated that a large amount of recharge entered the lower passages during all stages of development. The groundwater in the cave is aggressive with respect to sulfate. Discharge of water with higher mineralization was documented during the spring floods. During summer low-flow periods, subaqueous springs discharge waters under artesian conditions with a lower solute content. In the cave, the degree of saturation of water increases from the bottom to the top in the spring season and is the reverse in the summer. Seasonal variations in the groundwater chemical composition reflect the contribution from the artesian system. The geological data indicate a strong relationship between the karst features and the regional fault network. The characteristic features of the Ordinskaya Cave make it a model object of artesian hypogene speleogenesis.

The current water supply for the city of Sete Lagoas, Brazil, is almost entirely groundwater from the Sete Lagoas Karst Aquifer, with a small contribution from a fractured-basement rock aquifer. Characterizing the hydrogeologic processes is important for proper water resource management, avoiding contamination and other future issues. The main goal of this study is to identify active hydrogeological processes, such as possible surface–ground water interactions, sources of recharge, and the hydrochemical evolution of groundwater through the use of stable isotopes 18O and 2H and major ion data. The groundwater samples were collected from the karst aquifer (central urban area) and from the fractured aquifer (southern part of the city). Surface water samples were collected from the seven main lakes, and rainwater was sampled over a period of one year. The stable isotope results indicated the groundwater origin is directly from local precipitation, having a limited recharge period, and locally receiving surface water contributions. Groundwater quality in the central urban area may be influenced by surface water infiltration where the karst aquifer is in contact with overlying unconsolidated sediments. Some samples with nitrate concentration of 10 mg/L or higher indicates the natural composition of the groundwater has been altered by urban sewage contamination. The highest concentrations of major ions were found in the central region, where the most karstified area from the Sete Lagoas Formation is located. These data suggest a longer residence time for this water, indicating more mineralization, in accordance with the geological information.

Zoloushka Cave, the third longest gypsum cave in the world (92 km) and the world’s largest gypsum cave by volume (>0.7 million cubic meter), is an outstanding example of a large maze cave formed in a multi-story artesian aquifer system due to the upward leakage between the aquifers across a soluble unit. Although local settings and evolution caused some peculiar features in speleogenesis, as compared to other large maze caves in Western Ukraine, these singularities provide further insights on variants and mechanisms of both regional and general models of hypogene artesian speleogenesis. The cave is located in the area where the host aquifer system is generally confined until present, but in one of the more uplifted tectonic blocks where the gypsum was partially incised by the nearby valley of the Prut River during the Holocene and rapidly drained due to the quarry operations since 1946. The cave experienced considerable modifications and transformations in the course of the recent transition to unconfined conditions and subsequent artificial dewatering. The geomorphological breaching of the confined aquifer system in the cave area occurred in the Holocene, i.e., later than in the area where most other large maze caves in the region are located. A relatively stable position of the water table in the upper part of the gypsum during most of the Holocene caused pronounced widening of passages, which determined the anomalously large size of passages and high indices of areal karstification in some regions of the cave. The most intense development of conduits occurred in areas where the input of freshwater from the lower aquifer was more abundant. Quarry operation and accompanying groundwater withdrawal during the last 70 years caused drastic and rapid transformations in the cave environment.

The UK has a wide variety of hypogenic caves, including transverse maze caves, relict hydrothermal caves, gypsum mazes and hypogenic karst associated with water rising up deep thrust faults. While few of these are particularly extensive, they offer insights into the mechanisms of speleogenesis and mineralisation. The best developed hypogenic caves in the UK are in the Carboniferous limestones of northern England where at least nine network maze caves with plan lengths exceeding 1 km are known, almost all of which are accessible only via disused mine workings. In South Wales, relict hypogenic cave networks have been documented from cave systems surrounding the South Wales Coalfield. Hydrothermal cave systems are also known in the Bristol region in southern England, the Derbyshire Peak District and North Wales where they are associated with Pb–Zn mineralisation. In all three of these areas, active deep phreatic groundwater circulation is ongoing. Elsewhere in the UK, transverse artesian groundwater flow through Permo-Triassic gypsum in the Ripon area has led to the development of hypogenic cave systems and numerous sinkholes. This chapter documents for the first time all the known hypogenic cave systems found in the UK, discusses their modes of formation and outlines the potential for future discoveries.

Water availability restrictions are already a reality in several countries. This issue is likely to worsen due to climate change, predicted for the upcoming decades. This study aims to estimate the impacts of climate change on groundwater system in the Guarani Aquifer outcrop zone. Global Climate Models (GCM) outputs were used as inputs to a water balance model, which produced recharge estimates for the groundwater model. Recharge was estimated across different land use types considering a control period from 2004 to 2014, and a future period from 2081 to 2099. Major changes in monthly rainfall means are expected to take place in dry seasons. Most of the analysed scenarios predict increase of more than 2 ºC in monthly mean temperatures. Comparing the control and future runs, our results showed a mean recharge change among scenarios that ranged from ~-80 to ~+60%, depending on the land use type. As a result of such decrease in recharge rates, the response given by the groundwater model indicates a lowering of the water table under most scenarios.

The aim of the current study is to investigate the geochemical evolution of groundwater mineralisation and the inter-connexion between shallow karst aquifer and deep aquifer groundwater. The studied aquifer system is considered as the principal outlet of the south-eastern end of the northern Pyrenean overthrust, with a volumetric flow reaching 2000 m 3 /h. Water at the emergence is characterized by high mineralisation and temperature relative to groundwater at the regional scale. An eight years survey was carried out at the outlet based on a geochemical and isotopic approach. Surprisingly spring water mineralisation increases with increasing precipitations. 87 Sr/ 86 Sr ratios of sampled water range from 0.7085 to 0.7090. This ratio contrasts with that of the aquifer matrix constituted by Mesozoic marine carbonates and underlying evaporites. Furthermore, these ratios are significantly higher than in groundwater impacted by current or ancient seawater at the regional scale. These high 87 Sr/ 86 Sr ratios may reflect the dissolution of 87 Sr rich minerals such as the Triassic salty clay deposits present at depth. The good correlation between 87 Sr/ 86 Sr and TDS confirm the hypothesis of a contribution of deep saline and 87 Sr rich water. The temporal variations in mineralization and Sr isotopic signature may be explained by high recharge inducing a higher hydraulic pressure on the deep aquifer and an increased contribution of deep saline groundwater to the spring water. The data acquired on this aquifer system allow predicting the evolution of mineralization with climate trends where decreasing recharge would induce a decreasing salinity at the spring outlet.