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The coastal micro-confined aquifer (MCA) in Shanghai is characterized by shallow burial depth, high artesian head, and discontinuous distribution. It has a significant influence on underground space development, especially where the MCA is directly connected with deep confined aquifers. In this paper, a series of pumping well tests were conducted in the MCA located in such area to investigate the dewatering-induced groundwater fluctuations and stratum deformation. In addition, a numerical method is proposed for the estimation of hydraulic parameter, and an empirical prediction method is developed for dewatering-induced ground settlement. Test results show that groundwater drawdowns and soil settlement can be observed not only in MCA but also in the aquifers underneath it. This indicates that there is a close hydraulic connection among each aquifer. Moreover, the distributions and development of soil settlement at various depths are parallel to those of groundwater drawdowns in most areas of the test site except the vicinity of pumping wells, where collapse-induced subsidence due to high-speed flow may occur. Furthermore, the largest deformation usually occurs at the top of the pumping aquifer instead of the ground surface, because the top layer is expanded due to the stress arch formed in it. Finally, the proposed methods are validated to be feasible according to the pumping well test results and can be employed to investigate the responses of groundwater fluctuations and stratum deformations due to dewatering in MCA.

Unexpectedly high uranium concentrations, up to 930 µg L-1, approximately thirty times higher than the World Health Organization (WHO) guidance level, were observed in groundwater samples from the mountainous region near Rio de Janeiro City, the so-called “Regiao Serrana”, approximately 60 km from the city. This region is characterized by a large number of tourist activities and water-related industries, such as mineral water and breweries that can be impacted by these findings. In addition, the water supplies in small communities of this region are partially or entirely based on groundwater sources. Uranium contamination was observed in 7 of the 16 counties in this region. Based on these data, this study concluded that the probability of obtaining uranium-contaminated groundwater is high in some specific areas of this region. In addition, high 222Rn concentrations were verified, with levels reaching 1570 Bq L-1. Furthermore, a maximum level of 4.6 Bq L-1 210Pb was also measured, which has a WHO guidance level of 0.1 Bq L-1. Based on the present findings, it is suggested that any artesian well deeper than 80 m in this region should be tested for uranium and 222Rn.

The influence of climate change on the availability and quality of both surface- and ground-water resources is well recognized nowadays. In particular, the mitigation of saline water intrusion mechanisms in coastal aquifers is a recurrent environmental issue. In the case of the Nile delta, the presence of sea level rise and the perspective of other human-induced stressors, such as the next operation of the Grand Ethiopian Renaissance Dam, are threats to be taken into account for guaranteeing resilient agricultural practices within the future possible scenarios. Subsurface drainage offers a practical solution to the problem of upward artesian water movement and the simultaneous downward flow of excess irrigation water, to mitigate the salinization in the root zone. Subsurface draining systems can contribute to mitigate the vulnerability to climate change and to the increased anthropic pressure insofar they are able to receive the incremented flow rate due to the foreseen scenarios of sea level rise, recharge and subsidence. This paper introduces a rational design of subsurface drainage systems in coastal aquifers, taking into account the increment of flow in the draining pipes due to future possible conditions of sea level rise, artificial recharge and subsidence within time horizons that are compatible with the expected lifespan of a buried drainage system. The approach proposed in this paper is characterized by the assessment of the incremental flow through the drains as a function of various possible scenarios at different time horizons. Our calculations show that the impact on the discharge into the existing subsurface drainage system under the new foreseen conditions is anything but negligible. Thus, future climate-related scenarios deeply impact the design of such hydraulic structures, and must be taken into account in the frame of the next water management strategies for safeguarding agricultural activities in the Nile delta and in similar coastal contexts.

Summary A shallow (≈200 m) geothermal energy system is examined in the Faroe Islands, a 60-million-year-old volcanic archipelago in the Northeast Atlantic. The geothermal water has a heating capacity of approximately 150 individual households and consists of meteoric water approximately 3 years old. Water temperatures as high as 27°C in artesian wells are explained by a topography-driven vertical convection. The water flows into the boreholes from the north-northwest through fractures and flow tops and bases in the basalt exposed in surrounding high terrains. Of six influx zones, three are water carrying fractures that strike N – S and dip E.

The artesian springs of inland Australia are a unique habitat in what is otherwise an arid environment. They support a rich collection of endemic flora and fauna. Here, morphological and molecular data are employed to describe a new species, Chloris circumfontinalis Fahey & Fensham, endemic to artesian spring systems in central Queensland. A morphological ordination failed to distinguish this species from other Australian native flora, but the shape of the florets distinguishes it from the species with which it co-occurs. Phylogenies estimated from molecular data showed that the species represents a distinct lineage that may be sister to species of Chloris from outside Australia. Chloris circumfontinalis occurs only in the saline scalds that form around the springs, and population surveys at the two sites where it occurs indicated a threat status of Endangered under the IUCN Red List criteria.

Groundwater in upland floodplains has an important function in regulating river flows and controlling the coupling of hillslope runoff with rivers, with complex interaction between surface waters and groundwaters throughout floodplain width and depth. Heterogeneity is a key feature of upland floodplain hydrogeology and influences catchment water flows, but it is difficult to characterise and therefore is often simplified or overlooked. An upland floodplain and adjacent hillslope in the Eddleston catchment, southern Scotland (UK), has been studied through detailed three-dimensional geological characterisation, the monitoring of ten carefully sited piezometers, and analysis of locally collected rainfall and river data. Lateral aquifer heterogeneity produces different patterns of groundwater level fluctuation across the floodplain. Much of the aquifer is strongly hydraulically connected to the river, with rapid groundwater level rise and recession over hours. Near the floodplain edge, however, the aquifer is more strongly coupled with subsurface hillslope inflows, facilitated by highly permeable solifluction deposits in the hillslope–floodplain transition zone. Here, groundwater level rise is slower but high heads can be maintained for weeks, sometimes with artesian conditions, with important implications for drainage and infrastructure development. Vertical heterogeneity in floodplain aquifer properties, to depths of at least 12 m, can create local aquifer compartmentalisation with upward hydraulic gradients, influencing groundwater mixing and hydrogeochemical evolution. Understanding the geological processes controlling aquifer heterogeneity, which are common to formerly glaciated valleys across northern latitudes, provides key insights into the hydrogeology and wider hydrological behaviour of upland floodplains.

Eastern Arabian Peninsula represents the main natural groundwater discharge area of the Arabian platform fossil aquifer system. In such settings, connections between aquifers could strongly affect the flow dynamics, water quality and availability as well as karst formation and landscape evolution. Geological structures such as folds and faults are central to aquifer connectivity, yet their role on groundwater flow is poorly understood. Herein, we perform mapping of exposed and buried structural features in the Qatar Peninsula using Landsat, Sentinel-2 and ALOS-PalSAR scenes, correlated with field, GPR and isotopic data to assess their role in aquifer connections and groundwater dynamics. Our results suggest that ENE-WSW oriented fold-related faults act as vertical conduits along which artesian upward leakages from the deep Aruma aquifer take place into the shallower main aquifer unit (i.e. Umm er Radhuma and Rus) in southern Qatar Peninsula. On the other hand, downward leakage from the freshwater lens in the Dammam aquifer take place in northern Qatar Peninsula. The deep, brackish, and gaseous-rich waters ascending along faults in south Qatar Peninsula, in addition to degrading the water quality in the main aquifer unit, enhance dissolution of carbonates and evaporites leading to strong karstification that produces abundant collapse features. Our findings suggest that structure controls can add significant complexity to recharge mechanisms and groundwater dynamics in fossil aquifers. Future large-scale radar subsurface mapping will be essential to resolve the variability of the water heads in such areas and its correlation to structural discontinuities.

The extensive gypsum karst in the Western Ukraine is renowned for its giant maze caves. It is internationally important as a model example of hypogene artesian speleogenesis. The region contains the five longest gypsum caves in the world, accounting for well over half of the total known length of gypsum caves on Earth. This article describes the geological and hydrogeological conditions of these caves, their patterns, morphology, and origin.

Study region: The Bromo-Tengger volcanic aquifer system, (East Java, Indonesia). Study focus: Andesitic volcanic aquifers in Indonesia are an important source of groundwater supply for the population. The artesian flow from high discharge springs facilitates the access for irrigation and drinking water but continuously flowing artesian wells exert an increasing pressure on the groundwater resource. Given the complexity of the volcanic edifice, a multidisciplinary approach including geological, hydrometeorological, hydrochemical and isotopic measurements was performed to characterise the hydrogeological functioning of the volcano’s northern flank. New hydrogeological insights for the region: Two main hydrogeological systems are identified: a system with perched aquifers in the lava flows and pyroclastic complex, supplying low discharge springs or infiltrating to a deep flow system. The latter system is unconfined and provides groundwater to the downstream plain that hosts a confined multi-layer volcano-sedimentary aquifer. The joint implementation of a quantitative isotopic approach and a groundwater budget allows characterising aquifer recharge along the whole volcano flank. It is mainly controlled by the rainfall distribution that peaks around 1200 m elevation. The caldera basin on the top of the volcano has a very limited contribution to recharge. A conceptual hydrogeological model is proposed and compared to the main concepts of volcanic islands. This study is a first step for further scientific and management discussions to implement protection policies on the Bromo-Tengger aquifer system. Keywords: Hydrogeology, Volcanic aquifer, Andesite, Recharge, Isotopes, Hydrochemistry, Quantitative analysis

The basis for the research was the GIS project, which includes groundwater monitoring data on the territory of the Republic of North Ossetia-Alania. The paper presents generalized materials on fresh groundwater and comparative analysis of their quality change during water intake exploitation on the territory of the Republic of North Ossetia-Alania. Special geoinformation system (GIS) including groundwater parameters data for about 20 years of monitoring was developed. The results of chemical analyzes of groundwater for different years are systematized. The characteristics of deformation changes in aquifers and their relationship to surface waters are given. The evaluation of the groundwater protection against natural and anthropogenic pollution is given. The methodology for calculating of protective sanitary zones for water intakes with various hydrogeological conditions is developed, and measures for sanitary protection and revealing of pollution sources are offered (reasons for increasing hardness and mineralization of fresh groundwater in the industrial zone of Vladikavkaz city). Based on the investigation results, the conclusions on possible sources of hardness increase and deterioration of groundwater quality in the Ossetian artesian aquifer were drawn.

Policies surrounding energy development are frequently implemented in response to known or perceived problems. South Africa is in a unique position to develop prospective policies that build on knowledge gained from elsewhere. This paper provides a prospective analysis of hydrogeological risk pathways and vulnerability attributes in advance of anticipated shale gas operations in the Karoo Basin of South Africa. The ‘hazard-pathways-receptors’ approach is applied to define the hydrogeologic system in the context of potential sources of water resource contamination. This case study focuses on two critical hydrogeological risk pathways: regional groundwater flow and discrete structural features. Depending on the targeted area (hydro-litho-structural domain, depth of target, presence of aquitard, intrusion ratio), the capacity of deep natural pathways to enable hydraulic fracturing fluids, chemicals, or produced water to reach shallow groundwater, will be reduced or difficult. Deep artesian water could however be intercepted at different depths and, based on past groundwater exploration in the Karoo, water could flow into horizontal fractures or openings characterising the shallow aquifers: sills-ring complexes, lithological contacts, and transgressive fractures across dolerite dykes. However, above-ground water and wastewater management safeguards are needed to protect shallow groundwater from potential water quality degradation due to a) flowback or produced water b) stray gas and/or c) spills or illicit discharges that could introduce contaminants into groundwater resources. This paper describes a systematic approach to evaluate hydrogeologic risk pathways and informs adaptive management policies to protect South African groundwater resources.

Vast quantities of liquefaction ejecta repeatedly inundated properties during the 2010-2011 Canterbury earthquake sequence in New Zealand, resulting in differential ground surface subsidence and significant damage to buildings and urban infrastructure. There are strong spatial correlations between the occurrence of ejected sediment with groundwater pressure in deep aquifers. When geotechnical testing sites are grouped according to liquefaction vulnerability indices (to control variance relating to shaking strength, water table depth, and soil profile strength), places where ‘minor’ and ‘moderate-severe’ liquefaction occurred during the Mw6.2 Christchurch earthquake had distinctly higher aquifer pressure than sites where liquefaction was not observed. Together with observations of earthquake-induced pressure changes and inferred transfer of groundwater from deep aquifers to shallower levels, an interpretation is that leakage from aquifers with artesian (above ground) pressure provided an additional driving mechanism for surface manifestation of water and sediment. It is surmised that above-ground aquifer pressures further promoted suffusion and piping along fractures, flow-pathways and liquefied horizons. The Mw6.2 Christchurch earthquake is presented as an example where leakage of artesian groundwater likely contributed to the near-surface liquefaction-induced ground damage. The process can result in underprediction of liquefaction vulnerability so needs to be considered when evaluating potential for earthquake-induced liquefaction and ground damage wherever groundwater is confined.

A Hydrogeochemical study was carried out in Awe town and environs. The aim of the research was to determine the major, trace and rare earth elements content of the waters and their suitability for domestic, agricultural and industrial uses. Fifteen water sources from hand dug wells, a spring, pond and boreholes were collected and analysed. Inductively Coupled Plasma Mass Spectrophotometer was used to analyse the major cations trace elements and rare earth elements, Ion Chromatography was used to detect the anions and bicarbonate by titration method. In an attempt to determine the species of the trace elements in the waters, modeling was carried out using the WATEQ4F. Generally both the trace and the rare earth elements appear to be low in all the water sources and metal species obtain in the area indicate a dominantly reducing environment. Probable reasons for the low content of the trace elements may be the insolubility of their minerals, complexation , adsorption to clays and some oxides which has immobilized them. Chlorine/Bromine ratios indicate source of saline water (Cl/Br = 1,961) in the free flowing artesian borehole at Old Awe town to be evaporitic in origin. Four groundwater facies types were obtained in the study area; Ca+Mg-HCO3, Na+K-HCO3, NaCl, and Mg-SO4. Physico-chemical parameter, trace elements and their species determined in the area indicate that except for the acidity of the water, over eighty percent of water sources are fresh and soft and therefore good for general domestic uses. Percentage sodium, Sodium Absorbtion Ratios, magnesium hazards and salinity hazards also show that except for three sample locations, all other samples are within values recommended for agricultural purposes. Industries like Rubber manufacturing, sugar processing, textile mills, dairy product manufacturing and paper industry can be situated in the study area.

Water hazards threat the safety of underground mining. A detailed characterization of hydraulic parameters is helpful for the design of engineering projects to prevent underground water hazards. Utilizing aquifer’s natural artesian condition, water releasing tests are often performed in China’s underground mines. In this research, we propose to interpret water releasing test data with hydraulic tomography (HT) technique. A 216-hour duration test was performed to localize water hazard areas in Ningtiaota underground coal mine. Groundwater was released with four sequential stages from 30 boreholes. HT analysis clearly shows that the study area has a potential water hazard region in southern part by only using data from the first two stages, which coincides with existing water inrush incident location. With the addition of more pressure responses from stages 3 and 4, it discovers low transmissivity and storativity values in northern part. Our numerical examples further demonstrate that sequential water releasing tests produce comparable hydraulic parameter distributions to tomographic tests. In the end, we conclude that water releasing tests aided by HT technique can leads to a high resolution characterization of water hazard aquifers.

Artesian springs, which form carbonate mounds at the surface, occur in groups along the southwestern edge of the Great Artesian Basin (GAB), in northern South Australia. Their underground structure...

A decrease in flow from the iconic travertine mound springs of the Great Artesian Basin in South Australia has led to the oxidation of hypersulfidic soils and extreme soil acidification, impacting their unique groundwater dependent ecosystems. The build-up of pyrite in these systems occurred over millennia by the discharge of deep artesian sulfate-containing groundwaters through organic-rich subaqueous soils. Rare iron and aluminium hydroxysulfate minerals form thick efflorescences due to high evaporation rates in this arid zone environment, and the oxidised soils pose a significant risk to local aquatic and terrestrial ecosystems. The distribution of extreme acidification hazard is controlled by regional variations in the hydrochemistry of groundwater. Geochemical processes fractionate acidity and alkalinity into separate parts of the discharge zone allowing potentially extreme environments to form locally. Differences in groundwater chemistry in the aquifer along flow pathways towards the spring discharge zone are related to a range of processes including mineral dissolution and redox reactions, which in turn are strongly influenced by degassing of the mantle along deep crustal fractures. There is thus a connection between shallow critical zone ecosystems and deep crustal/mantle processes which ultimately control the formation of hypersulfidic soils and the potential for extreme geochemical environments.

Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3(-)) loading to surface and groundwater. We investigate variability and sources of NO3(-) in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008-12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3(-) stable isotopes (δ(15)N and δ(18)O). These data were augmented by historical data collected from 1937 to 2007. NO3(-) concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3(-) concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3(-) concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3(-). These results highlight the vulnerability of karst aquifers to NO3(-) contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008-10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3(-) than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously unrecognized source of NO3(-) to karst groundwater or other oxic groundwater systems.

The geochemical evolution of groundwater in the Ordovician-Cambrian aquifer system in the northern part of the Baltic Artesian Basin (BAB) illustrates how continental glaciations have influenced groundwater systems in proglacial areas. The aquifer system contains water that has originated from various end-members: recent meteoric water, glacial meltwater and relict Na-Cl brine. The saline formation water that occupied the aquifer system prior to the glacial meltwater intrusion has been diluted by meltwaters of advancing-retreating ice sheets. The diversity in the origin of groundwater in the aquifer system is illustrated by a wide variety in δ18O values that range from −11‰ to −22.5‰. These values are mostly depleted with respect to values found in modern precipitation in the area. The chemical and isotopic composition of groundwater has been influenced by mixing between waters originating from different end-members. In addition, the freshening of a previously saline water aquifer due to glacial meltwater intrusion has initiated various types of water-rock interaction (e.g. ion exchange, carbonate mineral dissolution).

The MH-2B borehole, a part of Project HOTSPOT, was drilled to a depth of 1821 m in late Cenozoic basalts, hyaloclastites and interbedded lake sediments, on the Mountain Home Air Force Base in southern Idaho, USA. Drillers encountered hot water (145°C) under artesian pressure at 1745 m in a narrow zone of highly fractured rock associated with a major sub-surface fault. X-ray diffraction (XRD) analysis identified corrensite (with and without smectite) between 1700 and 1800 m, but only smectite above 1700 m and below 1800 m. This corrensite horizon contains a relatively narrow zone of fracturing and hot artesian water near its centre but for the most part occurs in relatively massive basalt flows. No evidence was found for randomly interstratified chlorite-smectite.

Groundwater quality depends on different factors such as geology, lithology, properties of aquifer, land use, the physical condition of boundaries etc. Studying these factors can help users to manage groundwater quality. This study deals with the groundwater quality of an aquifer located in the southeastern part of Maharlou salt lake, Iran. This lake is located in the southeast of Shiraz and is the outlet of Shiraz sewages. Due to overexploitation of groundwater from the aquifer, the gradient of water table is from the lake towards the aquifer and therefore, saline water migrates to the aquifer. The phenomenon of salt water intrusion contributes to the deterioration of groundwater. In this research, groundwater types, maps of iso EC and iso ions, ion exchange in the mixing of fresh and salt water, salinity variation of the groundwater in the profile of well water column, and the salinity-time variation of the groundwater were studied. The gradual increase of the salinity of groundwater with depth from top to down in the aquifer indicates that salt water is located under fresh water. The time variation of physical and chemical parameters in the groundwater discharged from a well shows that the saline water in the bottom of the aquifer moves upward and destroys the quality of groundwater in the study area. Furthermore, Sachoun geological formation formed by evaporate deposits and evaporation from shallow groundwater are two other factors which decrease the groundwater quality.

Baghia-Chanda Beel, largest peat basin in Madaripur and Gopalganj (Bangladesh) districts occupies thick deposits of peat. Study focuses on the aquifer geometry and geochemical evaluation of groundwater in relation to occurrence and distribution of peat. Landuse map is generated to show the surface distribution of peat. Thick peat and clay layer respectively, with an average thickness of 7 ft, has been observed throughout the study area. Principal productive aquifer about 40 ft thick, is found at depth between 35 to 145 ft below ground surface. According to pH and EC values, groundwater is mildly acidic to slightly alkaline and fresh to brackish. High bicarbonate concentration which is more likely to be attributed from the oxidative degradation of peat is found at shallow aquifer below peat. Elevated sodium (Na+) and chloride (Cl-) concentrations in deep aquifer are due to the trapping of ancient sea water in the subsurface during Quaternary period. Although deep aquifer is extensively low in arsenic, 68% and 44% shallow groundwater samples are arsenic (As) contaminated according to WHO, 2011 and Bangladesh Drinking Water Standard (DoE, 1997) limit respectively. Assessment of Water Quality Indexes (WQI>100) suggests that water from deep aquifer is more suitable for drinking purposes.

The present study examines the geoarchaeological history of an oasis in Kharga Depression in central Egypt. El-Deir is renowned for its Ptolemaic temple and Roman fortress on the road from former Hibis (Kharga) to the Nile Valley. During the survey, spring mounds and irrigation soils belonging to an ancient agricultural zone were discovered, and further documented by ceramics found on the site. Our methodology combines the geomorphological interpretation of landforms (especially yardangs) with ceramics and 14C-dated charcoal to distinguish and date former agricultural areas in El-Deir. The results show that the oasis experienced several phases of soil accretion and destruction through time. Playa sediments were deposited in the humid early Holocene and severely eroded by deflation before the onset of irrigated agriculture between Pharaonic and Persian times. Very fast vertical soil accretion occurred in the Ptolemaic period, but irrigation soils were later destroyed during the Roman period by a combination of wind deflation and flash floods (second to fourth century A.D.), suggesting a period of climate instability. The case of El-Deir invites reevaluation of constructive agencies for the development of irrigated land and destructive agencies as limiting factors for the sustainability of agricultural practices in late antiquity.

The rapid expansion of economic activities in coastal parts of Nigeria has triggered an uncoordinated development of groundwater leading to stress on the resource. Hence a study was conducted to assess the hydrogeological characteristics of the shallow coastal aquifer of southern Akwa Ibom State, Nigeria. Emphasis was on the hydraulic characteristics, quality with respect to domestic and irrigation purposes and influence of seawater. The study result revealed that the aquifer consist of intercalations of clayey sand and sand. The aquifer is characterized by high hydraulic conductivity and transmissivity values. The groundwater flow direction is southwards with higher groundwater depletion in the dry season. Groundwater samples from hand dug wells and boreholes were evaluated based on World Health Organization standard and some indices, respectively, for drinking and irrigation uses. The groundwaters are fit for drinking and domestic uses. However, more than 70 % of the pH values are not within the allowable limits of between 6.5 and 9.2 for drinking and domestic use. Therefore, it is recommended that neutralizing filter containing calcite or ground limestone should be applied to raise the pH of the groundwater. Of the 10 parameters used to assess the water for irrigation use, only sodium adsorption ratio (SAR), magnesium hazard (MH) and magnesium ratio indicated the excellent quality of these waters. Na+-K+-HCO3 − constitute the dominant water type. Total dissolved solids and ratios of Na+/Cl−, Mg2+/Cl−, and Ca2+/SO4 2− and saltwater mixing index (SMI) suggest some level of seawater intrusion in the area.

The article considers the method of hydro geological calculation of wells at abrupt decrease of their flow rates as a result of injecting in them additional hydraulic resistance. Based on the previously carried out individual investigations, the authors present the analytic relation for determining the value of the resistance that ensures the target value of the well flow rate. The suggested relation enables staged automatic control of the flowing well operation. The article ascertains the applicability of Theis equation for determining the value of partial recovery of the head after abrupt decrease of the well flow rate. At that it is accepted that at the given point there is concurrently operating virtual injection well with constant rate, at the value equal to the diminished one.

Surface water is a scarce resource in Namibia with about sixty percent of Namibia's population dependent on groundwater for drinking purposes. With increasing population, the country faces water challenges and thus groundwater resources need to be managed properly. One important aspect of Integrated Water Resources Management is the protection of water resources, including protection of groundwater from contamination and over-exploitation. This study explores vulnerability mapping as a basic tool for protecting groundwater resources from pollution. It estimates groundwater vulnerability to pollution in the upper Niipele sub-basin of the Cuvelai-Etosha in Northern Namibia using the DRASTIC index. The DRASTIC index uses GIS to estimate groundwater vulnerability by overlaying different spatially referenced hydrogeological parameters that affect groundwater contamination. The study assesses the discontinuous perched aquifer (KDP) and the Ohangwena multi-layered aquifer 1 (KOH-1). For perched aquifers, point data was regionalized by a hydrotope approach whereas for KOH-1 aquifer, inverse distance weighting was used. The hydrotope approach categorized different parts of the hydrogeological system with similar properties into five hydrotopes. The result suggests that the discontinuous perched aquifers are more vulnerable than Ohangwena multi-layered aquifer 1. This implies that vulnerability increases with decreasing depth to water table because contaminants have short travel time to reach the aquifer when they are introduced on land surface. The nitrate concentration ranges between 2 and 288 mg/l in perched aquifers while in Ohangwena multi-layered aquifer 1, it ranges between 1 and 133 mg/l. It was observed that perched aquifers have high nitrate concentrations than Ohangwena 1 aquifer, which correlates well with the vulnerability results.

Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions.

Inactivation rates of Escherichia coli in groundwater have most often been determined in aerobic and oxidized systems. This study examined E. coli inactivation rates in anaerobic and extremely reduced groundwater systems that have been identified as recharge zones.Groundwater from six artesian wells was diverted to above-ground, flow-through mesocosms that contained laboratory grown E. coli in diffusion chambers. All groundwater was anaerobic and extremely reduced (ORP -300 mV). Cells were plated onto mTEC agar during 21-day incubation periods. All data fit a bi-phasic inactivation model, with95% of the E. coli population being inactivated11·0 h (mean k = 0·488 ±0·188 h(-1) ).The groundwater geochemical conditions enhanced the inactivation of E. coli to rates approx. 21-fold greater than previously published inactivation rate in groundwater (mean k = 0·023 ± 0·030 h(-1) ). Also, mTEC agar inhibits E. coli growth following exposure to anaerobic and reduced groundwater.Aquifer recharge zones with geochemical characteristics observed in this study complement above-ground engineered processes (e.g. filtration, disinfection), while increasing the overall indicator micro-organism log-reduction rate of a facility.

Artesian wells and lakes are found in the hinterland of the Hopq Desert, China. Analysis of soil profiles has revealed that the local vadose zone is always in a state of water deficit because of strong evaporation, and precipitation cannot infiltrate into the groundwater. This research indicated that soil water and surface water are recharged by groundwater and that the groundwater is recharged via an external source. Analyses of the stable isotopes in precipitation and of the water budget suggested that surface water in the Qiangtang Basin on the Tibetan Plateau might correspond to the groundwater in the Hopq Desert.

Analysis of groundwater chemistry can yield important insights about subsurface conditions, and provide an alternative and complementary method for characterizing basin hydrogeology, especially in areas where hydraulic data are limited. More specifically, hydrochemical facies have been used for decades to help understand basin flow and transport, and a set of facies were developed for the Roswell Artesian Basin (RAB) in a semi-arid part of New Mexico, USA. The RAB is an important agricultural water source, and is an excellent example of a rechargeable artesian system. However, substantial uncertainties about the RAB hydrogeology and groundwater chemistry exist. The RAB was a great opportunity to explore hydrochemcial facies definition. A set of facies, derived from fingerprint diagrams (graphical approach), existed as a basis for testing and for comparison to principal components, factor analysis, and cluster analyses (statistical approaches). Geochemical data from over 300 RAB wells in the central basin were examined. The statistical testing of fingerprint-diagram-based facies was useful in terms of quantitatively evaluating differences between facies, and for understanding potential controls on basin groundwater chemistry. This study suggests the presence of three hydrochemical facies in the shallower part of the RAB (mostly unconfined conditions) and three in the deeper artesian system of the RAB. These facies reflect significant spatial differences in chemistry in the basin that are associated with specific stratigraphic intervals as well as structural features. Substantial chemical variability across faults and within fault blocks was also observed.

Many researchers reported that artesian pressure exists in thick soft ground of Busan Nakdong river estuary. Artesian pressure in soft ground could affect rate of consolidation, settlement and drainage capasity of prefabricated vertical drain(PVD). This paper investigated consolidation behaviors of soft ground with partially penetrated PVD subjected to artesian pressure. Laboratory tests with 1-dimensional large column equipment and their numerical analyses were carried out. Test results showed that the consolidation settlement of clay ground with artesian pressure was higher than that without artesian pressure. Due to artesian pressure, the dissipation rate of excess pore water pressure was reduced in soft ground with artesian pressure, especially at bottom part of clay ground. Numerical results were in good agreement with experimental test results.

The assembly of a groundwater flow model for the shallow aquifer in Tianjin Municipality is outlined in this paper. Tianjin Municipality was selected because of its complicated hydrogeological conditions and rich data, which could be used to test a refined groundwater flow model for the shallow aquifer. When a shallow groundwater flow model is being assembled its recharge and discharge functions need to represent inflows from rainfall, irrigation return flows, seepage from rivers and reservoirs, and lateral inflows and outflows from evaporation, abstraction of groundwater for irrigation and industrial, and urban use. When abstracting groundwater, the water exchanges between a shallow aquifer and a deep aquifer also need to be considered. The real irrigation areas of Tianjin Municipality were input into the groundwater flow model, and the rivers and reservoirs were refined to the level of secondary tributaries and small scale reservoirs. The model calibration was carried out based on consideration of representative parameter values and their spatial distribution, the groundwater flow fields, the temporal variation in groundwater heads and the water balance for the years 2006–2008. It was concluded from a comparison of the observed and simulated groundwater heads that the precision of the model is high and that the simulated groundwater levels align with the real groundwater conditions. It is also concluded that the groundwater flow model for the shallow aquifer in Tianjin Municipality will be a useful tool for further studies about the relationship between shallow and deep aquifers and the surface environment.

More than 200 million people worldwide are exposed to excessive fluoride in drinking water. According to the World Health Organization, the optimal concentration range of fluoride in drinking water is 0.5 to 1.5 mg/L. Above this range, populations may contract dental fluorosis or, in severe cases, crippling skeletal fluorosis. In the Gokwe area in NW Zimbabwe, where drinking water contains up to 11 mg/L fluoride, fluorosis prevalence has previously been estimated at 62%. This paper investigates the water quality of 126 water sources in Gokwe (58 pumped boreholes, 15 flowing artesian boreholes, 46 wells and 7 streams). The water chemistry, determined from high performance ion chromatography and field measurements, showed that the water source types exhibit significantly different (P < 0.05) concentrations of F−, Cl−, Na+, K+, Ca2+, Mg2+, temperatures, pH and conductivity values. Thirty-five (28%) of the 126 water sources (18 pumped boreholes, 15 artesian boreholes, one well and one stream) contained F− > 1.5 mg/L, indicating that fluoride contamination in the area is a characteristic of deeper groundwater, possibly due to its interactions with the potentially fluoridic coaly and carbonaceous materials of the Lower Karoo Aquifer at depth. The plausibility of providing alternative low fluoride water, and defluoridation, should be investigated.

Vertical drain has usually been used to accelerate the consolidation of soft clay deposits with high moisture content. Busan thick clay deposits are subjected to artesian pressure from an aquifer in sand and gravel layers. However, effect of artesian pressure existing in drainage-installed soft ground on consolidation behaviors is not well known. This paper investigates the consolidation behavior of drainage-installed soft ground at the Nakdong river estuary with artesian pressure and without artesian pressure. A series of one-dimensional large size column test was carried out to find out the consolidation characteristics of clay. Test results indicated that total settlement of clay with artesian pressure was higher than that without artesian pressure because effective stress decreased due to upward flow. Dissipation rate of excess pore water pressure delayed and excess pore water pressure did not fully dissipate in clay layer with artesian pressure. Undrained shear strength of clay ground with artesian pressure was lower than that without artesian pressure.

This paper presents an analytical model for describing the tidal effects in a two-dimensional leaky confined aquifer system in an estuarine delta where ocean and river meet. This system has an unconfined aquifer on top and a confined aquifer on the bottom with an aquitard in between the two. The unconfined and confined aquifers interact with each other through leakage. It was assumed that the aquitard storage was negligible and that the leakage was linearly proportional to the head difference between the unconfined and confined aquifers. This model's solution was based on the separation of variables method. Two existing solutions that deal with the head fluctuation in one-dimensional or two-dimensional leaky confined aquifers are shown as special cases in the present solution. Based on this new solution, the dynamic effect of the water table's fluctuations can be clearly explored, as well as the influence of leakage on the behaviour of fluctuations in groundwater levels in the leaky aquifer system. Copyright © 2015 John Wiley & Sons, Ltd.

Although drinking water is readily available in Benin, its quality presents a public health concern. The district of Ahomadegbe in the commune of Lalo is characterized by several artesian wells. Unfortunately, anthropogenic factors negatively affect the drinking water quality in this area. The aim of this research was to study the microbiological quality of drinking water in the Ahomadegbe district, and to review household water treatment methods employed by the local population. Thirty-five water samples were taken—at water collection points, at selected points along the water transportation system and from water storage facilities, and microbiological parameters were measured. Qualitative data were collected via in-depth interviews with key informants regarding local household water treatment methods. Results reveal that there is a significant degree of microbiological pollution of drinking water in this district, particularly during the water transportation and storage stages where microbiological pollution exceeds levels approved by the World Health Organization. Local residents are familiar with several household water treatment methods. However, these methods are inconsistently applied, which limits their effectiveness. In addition to improving the quality of the drinking water resource itself, it is important to set up interventions relating to water treatment methods in local households.

Ghadames basin is one of the important groundwater basins in Libya. This basin covers an area of about 215,000 km2 in northwestern Libya. This groundwater basin consists of two major aquifer systems. The upper aquifer system mostly formed of carbonate rocks (Mizdah and Nalut formations). The lower aquifer system formed mostly of sandstone known as Kiklah formation. The two aquifer systems are separated by semi-confining layers known as Yefren marl. The lower aquifer system is considered as the main aquifer for water supply. The water resource (mostly from the lower aquifer system) in these systems is used for domestic, irrigation and fodder drinking. The domestic use of water is to supply water to the cities and towns in western part of the country and in the northern flanks of the basin, and plans to transport water to the coastal cities in northwestern part of the country. The existing total amount of extracted water is 132 Mm3/year, and about 20% of it used for domestic uses. The planned water extraction is 223.8 Mm3/year about 55% of it will be used for domestic uses. The hydrogeological situation for this basin has been studied in this study using data from previous hydrogeological exploration programs, evaluation of the data from the existing extraction and observation water wells, pumping tests data used to evaluate aquifers hydraulic parameters, and construction of hydrogeological cross-sections to know the aquifer systems geometry. Hydogeological computer model was constructed to evaluate the aquifer hydraulic parameters using the historical water extraction, and water levels and drawdowns. The model is then used to predict the future drawdown which has been found to be in the range 55 to 60 m after 50 years of extraction.

Short-Term Low Volume (STLV) Sea Water Desalination Plant of 6000 m3/d is under construction in the middle area of Gaza Strip. The plant will provide desalinated water for 75,000 inhabitants in regions in Khanyounis and Rafah. The intake of desalination plant will be indirectly from four beach wells. This article aims at providing the environmental impacts of these wells on the aquifer and the mitigation measures in case of negative impacts. In order to study the impacts of beach wells on the aquifer, a prediction groundwater three-dimensional model for the beach wells area, starting from the year 2000 until year 2030, was used. MODFLOW software was used for modeling the groundwater flow and SEAWAT software was used to model the seawater intrusion effect. The aquifer parameters were set as if they were in the transient model. The long term seasonal recharge rate for the summer and winter is considered to represent the seasonal differences in recharge through each year. The study showed that the steady four-meter drawdown in the beach wells will force the flow from the eastern direction to the sea. This will have positive impacts on the aquifer since it will decrease the seawater intrusion to the aquifer. The beach wells will pump water with Cl concentration equal to 18,000 mg/l. This means that the beach wells will accelerate the flow from the aquifer to the sea direction but still the pumped water is considered as seawater. This indicates the positive impacts on the groundwater aquifer since it will decrease the seawater intrusion in the beach wells area (Gaza Strip Middle area). In conclusion, these beach wells in this desalination plant (small capacity) are safe for the groundwater aquifer and it will decrease the effect of seawater intrusion on the aquifer.

Clouse to faults or unstable areas where an earthquake could happen with capacity of affecting buildings or infrastructure, there is often a previous energy that wanders around surroundings, this energy regularly is associated to electromagnetic emissions that generate an electric potential frequently studied as very, ultra-low and extreme frequency emissions (VLF-ULFELF_ EM) by remote sensing; under the assumption that this natural potential exist, in aquatic environment within the micro-seismic active area in the coastal border of Guerrero and Oaxaca estates, Mexico, an intensive conductivity monitoring in two artesian well was carried out. The results of intensive conductivity (μS/cm) monitoring done since March to July of 2015, using a low-cost Data logger sensor are presented. The results obtained of the study of 235 seismic events show that 61.64% of them manifest prior conductivity oscillation versus 38.36% of early conductivity oscillation; a discussion of the origin of such oscillation and the possible relation with to recharge flux, ground light compression, ground tilt, local electromagnetic energy emissions, human interaction, was debated. The data analysis for long periods of conductivity monitoring and seismic events show that when the number of seismic events became intense, conductivity decreases and vice versa, resulting large fluctuations that grew over time lake waves, within the studied area appears to be there is a possible previous long term energy oscillation associated to the process of earthquakes manifestation around.

Within McHenry County, IL, the fastest growing county in Illinois, groundwater is used for 100% of the water needs. Concerns over water resources have prompted the investigation of the surficial sand and gravel aquifers of the county. While the eastern portion of the county is urbanizing, the western portion remains devoted to agriculture. High-capacity irrigation wells screened within the surficial sand and gravel aquifer are used for crop production. To assess the impacts of the irrigation wells on the aquifer, a groundwater flow model was developed to examine five different scenarios reflecting drought conditions and increased pumping. Results show that the surficial sand and gravel aquifer is capable of meeting current water demands even if recharge is decreased 20% and pumping is increased 20%. The additional loss of discharge and increases in pumping result in head differences throughout the aquifer.

To identify the potential groundwater bearing zones for future groundwater resources development of the study area, an investigation has been made using lithology, groundwater monitoring and elevation data. The stratigraphic cross-sections of the area reveal six distinct hydrostratigraphic features viz. clay-silt-sand, fine sand, fine to medium sand, medium sand, medium to coarse sand and coarse sand. On the basis of lithological information, the groundwater bearing zone of the area has been divided into two main hydrostratigraphic units viz. aquitard and aquifer, which consist of clay-silt-sand and sands of different grain sizes respectively. The aquifer zone is further divided into two categories: “small scale aquifer” made dominantly of fine and “main aquifer” comprising of fine-medium to coarse sand. The annual fluctuation of water table in the study area is observed from 4.9 m to 5.6 m. The area is demarcated as three different groundwater bearing zones based on Catastrophe theory using GIS.

Numerous frost mounds exist on the meander belt and alluvial fan around Arsain Gol River in Darhad basin, northern Mongolia, at the southern fringe of the north-eastern Eurasian permafrost zone. In this environment, abundant water supply and inter-permafrost taliks may allow the development of artesian pressure that leads to groundwater upwelling. The aim of this study was to determine the formation chronology of pingos in this region. The Arsain pingo was drilled to a depth of 35 m to determine the stratigraphy, and data were collected on ground-ice stable isotopic composition, electrical resistivity, ground temperature, and radiocarbon dating and interpreted in conjunction with the chronology of paleo-lake retreat in the basin. A 10 m thick ice core sandwiched between fine-grained lacustrine sediments was identified by drilling and electrical resistivity tomography (ERT). Stable isotope values of ice core samples indicated Rayleigh-type isotope fractionation during the freezing of liquid water. Consequently, closed-system freezing of artesian groundwater appears to be the driving mechanism of pingo formation. Near-surface, segregated ground ice formed from the open-system freezing of meteoric water, concurrent with pingo growth. The lake coverage was extensive until about 10,000 years before present (yr bp), and the growth of the Arsain pingo began after 4500 yr bp, when the paleo-lake was completely drained. The pingo is not presently growing because of a limited groundwater supply to feed the ice core. Copyright © 2015 John Wiley & Sons, Ltd.

Summary The response to river stage fluctuation of a drilled well penetrating a confined aquifer was simulated using a stream–aquifer interaction algorithm. Because the confined aquifer is overlaid by a water table aquifer, the algorithm was coupled with formulae used to correct the heads for mechanical loading. The coupling of stream–aquifer interaction and mechanical loading models was tried for the first time in this study. The test site was a drilled well installed on the Montalto Uffugo aquifer located at the Calabria University groundwater test field (Calabria region, south of Italy). This aquifer comprises a 44 m-thick sand bank bounded on bottom and top by clay layers and covered by a 7 m-thick sandy conglomerate, being adjacent to the Mavigliano River. Overall, the head changes caused by a river stage raise represented a contribution of 49.3–57.8% to the total head, while mechanical loading accounted for the remaining 50.7–32.2%. The loading was triggered by a sequence of short-spaced rainfall events lasting for a total of 167 days, which caused recharge to the unconfined aquifer thickening the water column by some 3.1 m.

Extraction of groundwater for agriculture has resulted in the loss of springs across arid regions of the globe. The history and fate are recorded of the artesian springs of Egypt’s Western Desert, from ancient times to the present, spanning the rise and fall of the great civilisations from the Pharoanic dynasties to Persian, Greek and Roman conquests. The study area includes oases Kharga, Dakhla, Bahriya, Farafra and Siwa, and several outer and small oases around Siwa and the edge of the Qattara Depression. The region is hyper-arid, receiving 10 mm or less average annual precipitation and evaporation rates are in the vicinity of 3,000 mm/a. Groundwater in the oases is largely derived from bores discharging from the Nubian Sandstone Aquifer. Based on an extensive survey, conducted for the first time, attention is drawn to the rapid demise of springs as a result of modern irrigation schemes which continue to deplete groundwater supplies.

Made available in DSpace on 2018-11-12T17:26:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-01. Added 1 bitstream(s) on 2021-07-14T17:50:50Z : No. of bitstreams: 1 S0103-65132016000200385.pdf: 1892323 bytes, checksum: 3766cbfc69de1a642bf54ff36fd77ee1 (MD5) Resumo O problema abordado neste trabalho consiste na redução dos custos de energia elétrica necessária para o funcionamento de bombas hidráulicas, que são utilizadas para captar água de poços artesianos ou estações de tratamento de água para abastecer reservatórios distribuídos por bairros de uma cidade. A população é então atendida por força gravitacional. Como o custo da energia elétrica varia ao longo do dia, é necessário um planejamento do funcionamento das bombas. O problema consiste em decidir quando as bombas devem permanecer ligadas e quando deve haver transferência de água entre os reservatórios para que a demanda de cada reservatório seja atendida, minimizando os custos com energia elétrica. Este problema é modelado como um problema de programação linear inteira, e uma solução heurística é proposta. Experimentos computacionais mostram a eficiência da heurística e como a abordagem pode ser utilizada para analisar o impacto de alterações na infraestrutura do sistema de abastecimento. Abstract The problem considered in this paper consists of the reduction of electrical energy costs necessary for the operation of hydraulic pumps, which are used to collect water from artesian wells or from a Water Treatment Station to fill water tanks located in many districts of a city. The water is then supplied by gravitational force. Because the cost of electrical energy varies throughout the day, a pump running schedule is necessary. The problem consists of determining when the pumps must be on and when there must be water transfer among tanks to ensure that the demand of each water tank be supplied, thereby minimizing the costs of electrical energy. This problem was modeled as an integer linear optimization problem, and a heuristic solution to the problem is proposed. Computational experiments show the efficiency of the heuristic and highlight how the approach can be used to analyze the impact of changes in the infrastructure of the water supply system. Universidade Estadual Paulista Universidade de São Paulo Universidade Estadual Paulista

Land subsidence caused by dewatering of deep foundations pit has currently become the focus of prevention and control of land subsidence in Shanghai. Because of the reliance on deep foundation dewatering pit projects, two comprehensive test sites were established to help prevent land subsidence. Through geological environmental monitoring during dewatering of a deep foundation pit, the analysis of the relation between artesian water level and soil subsidence, some basic features of land subsidence caused by dewatering of deep foundation pits are elucidated. The results provide a scientific basis for prevention and control of land subsidence caused by dewatering in deep foundation pits.