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The ability of sodium carboxymethyl cellulose (Na-СMC) to inhibit scale formation in nanofiltration (NF) of hard artesian waters have been studied. Na-СMC inhibition ability was examined in comparison with ACUMER scale formation inhibitor. We used three types of membranes: ESPA1, OPMN-P, and AMN-P. It was revealed that the event of absence of the inhibitor in the hard artesian water membranes' flux is decreasing. Level of flux leads to decrease in virgin membranes that depend on their type. Scale formation process gradually decreases when Na-СMС or ACUMER was added to the water. Na-CMC inhibition ability is comparable with ACUMER with the use of less dense membranes OPMN-P, AMN-P. Na-КМЦ и ACUMER models of inhibition action in NF of hard artesian water are proposed when different types of membranes are used.

The rising demand for water and the contamination of shallow water table aquifers has led authorities in NE Morocco to look for deeper groundwater resources in the Triffa Plain, namely in Lower Jurassic (Lias) dolomitic limestones. The liassic aquifer is of strategic importance for the development of the region, however, its hydrodynamic behaviour is poorly understood due to lack of hydrogeological data and block structure. This article presents a first effort towards understanding the structure and hydraulic behaviour of the aquifer. Exploration borehole data and results from geophysical campaigns were integrated into a GIS environment to build a preliminary model of the aquifer structure. The aquifer behaves as an unconfined aquifer in the northern part of the Beni Snassen Mountains (the recharge area), but as it dips to the north, it becomes confined by marls and shales of the Middle/Upper Jurassic. Even though piezometric level data are scarce, a tentative piezometric map was produced. Three blocks separated by NW–SE trending faults in a horst and graben structure, with distinct flow behaviours were identified: Berkane, Fezouane and Sidi Rahmoun blocks. Those blocks also show differences in hydraulic conductivity distribution. As a result of the reaction with the dolomitic limestones, the groundwater is of calcium-magnesium bicarbonate type. Groundwater temperature as measured in springs ranges from 29 °C to 37 °C in springs and constitutes a potential low enthalpy geothermal resource.

Due to increases in water demand, the City of Kenedy, TX, USA must expand their small drinking water supply in the Gulf Coast aquifer system. Groundwater wells owned by the City of Kenedy, Karnes County, TX were examined to estimate properties for the Jasper aquifer. Conditions of four wells were assessed, after which two wells were rehabilitated and used as pumping wells in aquifer tests. Aquifer tests show that recovery in observation wells was not coincident with the cessation of pumping. Post-pumping data were selectively excluded so that only recovery data were used for analyses. Transmissivity for the Jasper aquifer ranges from 102 to 242 m2 d−1, and storativity ranges from 6.9E−05 to 3.3E−04. Transmissivity computed from recovery data was approximately 25 % higher than transmissivity computed from time-drawdown data. Field measured specific capacities and drawdowns were compared to theoretical specific capacities and drawdowns to calculate pumping well efficiencies in the range of 52.2–99.4 %. This study indicates that water demand for the City of Kenedy could be met by incorporating the tested wells into the water supply system. Future studies should be designed to estimate groundwater recharge rates and a complete water balance for computing a sustainable maximum annual yield.

KS043 is a stratified site associated with a complex of artesian springs. The archaeological remains, as well as a series of radiocarbon determinations, date the site to between 4800 and 4200 b.c. Our study suggests a connection between Saharan pastoralists, forced to move into oasis areas by increasing aridification, and the first Predynastic cultures of the Nile Valley. The site is the only well dated stratified settlement attributed to the Late Neolithic in the eastern Sahara that is characterized by Tasian cultural traditions.

The focus of the present work is to characterize a tropical, coastal aquifer and to carry out its vulnerability to saltwater intrusion using hydrogeological parameters. The characterization of the aquifer involves pumping tests, vertical electrical sounding, and water quality analysis carried out at 41 monitoring wells. The area under investigation lies between two tropical, seasonal, tidal rivers, i.e., Pavanje and Gurpur rivers, joining the Arabian on the west coast of India. The aquifer is predominantly shallow and unconfined, having moderate to good groundwater potential with transimissivity and specific yield ranging from 49.2 to 461:4 m2∕day and 0.00058 to 0.2805, respectively. The electrical resistivity tests indicated that the thickness of the aquifer ranges from 18 to 30 m. The study also investigates the saltwater affected areas in the region the vertical electrical sounding and water quality analysis. The resistivity results revealed several probable isolated saltwater intruded pockets in the region with resistivity less than 70 Ωm. From the salinity analysis of water, the locations that are affected during February to May (summer) and throughout the year are identified. The wells that are located close to the coast (< 350 m) and at lower elevations (well bottom 200 ppm) during the summer period from tidal inflow along the rivers. The water samples were also analyzed for chloride to bicarbonate ratios during December to May at all the monitoring wells and were found to be exceeding the allowable limit at several locations. The saltwater vulnerability maps are derived for the area by the index-based method using the hydrogeological parameters. The method was found to be effective while compared to the field observations. The results from the analysis indicate that the aquifer is medium to highly vulnerable to saltwater intrusion at majority of the locations. The impact of projected sea level rise by 0.25 and 0.50 m from the climate change is also assessed on the vulnerability of the region to saltwater intrusion. DOI: 10.1061/(ASCE)HE.1943-5584.0000524. © 2012 American Society of Civil Engineers

The artesian aquifers provide economical and sustainable source of groundwater for irrigation and domestic use. GIS (Geographic Information System) was used for development and integration of spatial databases, analysis and visualization of spatial data in two- and three-dimensional views. The aquifer system of Daraban Rod-Kohi area of DI Khan was analyzed to identify potential artesian aquifers using geological sections of the observation wells representing detail of subsurface lithology and strata encountered. According to an estimate, about 1,700 million m3 of extractable volume of groundwater exists in this part of rod-kohi area. Different profile sections were drawn to analyze the subsurface condition of the study area using Rockworks GIS-based software. The geo-processing technique of horizontal litho-blending was utilized for lithological modeling. Based on stratigraphic information of the area, three distinct aquifers were identified down to a depth of about 200 meters among which two are semi-confined to confined having prospects of artesian water. The 2D and 3D analysis show that characteristics of the confined aquifers vary spatially with the subsurface lithology and structural setup of the area. The depth range of confined layer-1 is found between 118 and 133 meters while of confined layer-2 between 182 and 195 meters. The output data indicated a close agreement with the observed data of the artesian wells. The study results can provide base for detail investigation of artesian resource and selection of potential sites for installation of artesian wells in the target area.

The leaching processes along the flow path and over abstraction of the alluvial aquifer, the principal aquifer in delta Tokar, by the agricultural and domestic sectors and natural factors, have led to its salinization which may be due to interaction between geological formations and adjacent brackish and saline water bodies as well as seawater transgression. The main objectives of this study are to assess the hydrochemical characteristics of the groundwater and to delineate the locations and the sources of aquifer salinization. Water samples in the project area were chemically analyzed for major cations and anions at the laboratory by the standard analytical procedures. Chemical data and water level measurements were manipulated using GIS techniques for hydro chemical and flow direction maps and piper diagram for chemical facies and SPSS software for statistical analyses such as basic statistics (mean and standard deviation) and Spearman’s correlation matrix. The general flow direction of the groundwater is from Southwest towards East and Northeast. The hydraulic gradient is relatively steeper at the apex of the delta (0.06) and amounts to 0.005 at the distal part of the delta. The average transmissivity value of the water bearing formations was found to be about 4.5 × 103 m2/s, whereas, the storage coefficient was about 0.28. A hydrochemical study identified the locations and the sources of aquifer salinization and delineated their areas of influence. The investigation indicates that the aquifer water quality is significantly modified as groundwater flows from the southwestern parts of the study area, where the aquifer receives its water by lateral underflow from Khor Baraka flood plain, to the central and northeastern parts, with few exceptions of scattered anomalous concentration pockets in the deltaic plain. Significant correlation between TDS and/or EC with the major components of Na+, Cl−, and SO4−2 ions is an indication of seawater influence on the groundwater salinity. Moreover, Cl−, SO42−, and Na+ are predominant ions followed by Ca2+ and HCO3−. Hence, four types of groundwater can be chemically distinguished: Na–Ca–SO4–Cl– facies, Na–Cl–SO4–HCO3– facies, Na–Ca–Mg–SO4–Cl–HCO3 facies, and Na–Ca–Mg–Cl–SO4 facies. The processes that govern changes in groundwater composition as revealed by chemical and statistical analyses are mainly associated with over-abstraction, biodegradation, marine intrusions, and carbonate saturation.

Eleven Quaternary fissure ridge travertines from Mammoth Hot Springs (Wyoming) and seventeen ones from Bridgeport (California) were mapped and studied with a morphotectonic approach to understand possible relationships between travertines and active versus passive tectonics. Results are compared with other known geothermal fissure ridges on the Earth. The studied fissure ridges are all located in the hangingwall of normal faults, but the fissure ridges appear as non-dislocated by faults, rather by axial fissures. Both in the two principal study areas and elsewhere, azimuthal analyses of faults and fissure ridges show that the distribution of fissure ridge long axis is rather dispersed around the strike of the local normal faults. No correlation occurs between the fissure ridge length and the angle between the strike of the normal fault and the strike of fissure ridges. The studied fissure ridges are 2 to 360 m long (mean length: 72.1 m), 1 to 15 m wide (mean width: 6.7 m), and 0.5 to 8 m high (mean height: 3.9 m). Fissure ridge aspect ratios show a moderate correlation between the length and both the width and the height of fissure ridges, whereas the correlation between width and height is less marked. The growth in height and width of ridges appears as much more inhibited than in length. A model is proposed in which fissure ridge travertines grow with enhanced elongation along one sub-horizontal direction, which seems moderately controlled by the associated normal fault and the regional extension. Other factors, such as the inherited fracture network and the geothermal and artesian pressure of fluids (fluid discharge) may be important in the development of the studied fissure ridges. Results from this study may contribute to the knowledge of factors that control the long-term geothermal circulation and also the long-term hermetic durability of CO 2 subsurface repositories.

We analyze event archives and continuous waveform data recorded by the Cooperative New Madrid Seismic Network from 1995 to 2008 in conjunction with waveform cross‐correlation techniques to investigate the spatiotemporal distribution of small‐magnitude ( M D

Summary Environmental isotopes and 14 C dating were applied to estimate ages and recharge sources of deep groundwater (⩾150 m bgl) in south-east Bangladesh. With one exception, deep groundwater is shown to have been recharged more recently than 10 Ka (range 3–9 Ka, mean 7.6 Ka), under climatic conditions indicated by δ 18 O and δ 2 H as similar to the present day. Groundwater age distributions have been used to infer the scale of aquifer hydraulic anisotropy. 2D groundwater flow modelling is able to reproduce the observed vertical profiles of groundwater age, as determined at two locations, when the aquifer is assigned a permeability anisotropy ( K x / K z ) of at least 10 3 . Under these conditions, deep groundwater originates as recharge in the hill regions at the eastern boundary of the basin. Recharge rates estimated from the groundwater ages are close to an estimate of the current rate of deep groundwater abstraction. Cautious development and careful monitoring are therefore necessary, as excessive deep groundwater pumping could draw dissolved arsenic from the shallow levels of the Bengal Aquifer System (BAS) and contaminate the deep groundwater resource.

Studying results of the groundwater isotope composition in the Neogene-Quaternary and Mesozoic sediments of the Azov-Kuban and Eastern Pre-Caucasian artesian basins have shown in the Pliocene sediments a rather wide distribution of “relict” groundwater, formed because of melting of the Late Pleistocene Caucasian glaciers, as well as of groundwater formed due to its mixing with the meteogenic waters of the subsequent Holocene infiltration cycles. Also, the areas are revealed in the Lower-Miocene sediments where meteogenic waters are mixed with sedimentation waters, while in the Mesozoic formations—the areas where into the sedimentation waters wedge-shaped meteogenic waters of Pleistocene and Holocene infiltration periods are intruded.

The karstic upper Floridan aquifer in north-central Florida (USA) is recharged by both diffuse and allogenic recharge. To understand how recharged water moves within the aquifer, water levels and specific conductivities were monitored and slug tests were conducted in wells installed in the aquifer surrounding the Santa Fe River Sink and Rise. Results indicate that diffuse recharge does not mix rapidly within the aquifer but instead flows horizontally. Stratification may be aided by the high matrix porosity of the eogenetic karst aquifer. Purging wells for sample collection perturbed conductivity for several days, reflecting mixing of the stratified water and rendering collection of representative samples difficult. Interpretive numerical simulations suggest that diffuse recharge impacts the intrusion of allogenic water from the conduit by increasing hydraulic head in the surrounding aquifer and thereby reducing influx to the aquifer from the conduit. In turn, the increase of head within the conduits affects flow paths of diffuse recharge by moving newly recharged water vertically as the water table rises and falls. This movement may result in a broad vertical zone of dissolution at the water table above the conduit system, with thinner and more focused water-table dissolution at greater distance from the conduit.

Coastal aquifers are considered as major sources for freshwater supply worldwide, especially in arid zones. The weak rainfall as well as the intensive extraction of groundwater from coastal aquifers reduce freshwater budget and create local water aquifer depression, causing both seawater intrusion and a threat to groundwater. This phenomenon was observed in the Jerba Island which is located in southeast Tunisia. Jerba’s unconfined aquifer shows high values of groundwater salinity reaching, locally, 17 g/l and a strong contrast between some zones of the aquifer. High pumping rates and weak recharge disturb the natural equilibrium between fresh and saline water causing water salinization in most areas of the island. This study aims at establishing the salinity map of the aquifer and identifying the origin of groundwater salinization. The salinity map shows that zones characterized by low groundwater salinity are located in the center of the study area. High groundwater salinities are observed near the coast and in some parts having low topographic and piezometric levels. Groundwater geochemical characterization, and Br/Cl and Na/Cl ratios suggest that the origin of abnormal salinity is seawater intrusion. Considering groundwater salinity values and Br concentrations, a seawater intrusion map is established. It shows that many areas of the unconfined aquifer are contaminated by mixed groundwater and seawater. The statistical analysis demonstrates that high mineralization of the groundwater is due to gypsum and carbonate dissolution coupled with the mixed groundwater and seawater in many areas.

The multilayered aquifer of Zeroud basin is characterized by the hydrodynamic complexity due to natural (geology) and anthropogenic (management) features. Stable and radioactive isotope data have been used to investigate the origin of the groundwater and its recharge area and to understand the deep groundwater system within the southern Kairouan sedimentary basin. Most of the stable isotopic data indicate that most deep groundwater samples derived either from meteoric water or from the Zeroud River, and were not affected by any significant degree of evaporation during recharge. Current tritium concentration in the groundwater is very low. However, it proved useful in the qualitative identification of modern recharge and mixing of recent and old groundwater. Radiocarbon-deduced ages range from more than 30,000 years to modern. A modern recharge characterizes the deep aquifer upstream of the basin. The groundwater with ages range from more than 30,000 years and depleted of heavy isotopes are found in the deeper aquifer (aquifer B), downstream of the basin, and could be inherited from paleorecharge.

Salinization is a common environmental problem of groundwater contamination, particularly in developed coastal aquifers. The Sfax basin is located on the Mediterranean coast, southeastern Tunisia, and is dominated by industrial activities. The problem of groundwater mineralization in the south part of this aquifer has long been attributed to the marine influence. In this study, a combined hydrogeological and isotopic survey using chemical tracers was conducted in addition to discharge and groundwater level measurements. The results preclude seawater intrusion as an origin of groundwater mineralization. It seems that the main source of groundwater mineralization is due to the mixture with salty water lodged in the C/T (Cenomanian-Turonian) aquifer. This mixture process is carried out by the simultaneous effect of (1) a lateral flow of saline water coming from C/T aquifer in the southwest (Menzel Habib) and (2) a local vertical leakage from the same C/T formation which forms the basement of the studied aquifer. The depleted isotope signature of the majority of groundwater is characteristic of old recharge occurring during the late Pleistocene-Holocene, with the exception of some local recent refill areas.

Before seismic retrofits could be made to the Crane Valley Dam, in Madera County, California, a dewatering system had to be installed at the downstream toe of the structure. Because of the paramount importance of controlling hydraulic conditions immediately below the large dam, the design of the dewatering system required sophisticated groundwater modeling and careful attention to prevent problems associated with the artesian conditions and low-permeability soils present at the site.

Integrated approach has been used to investigate the hydrogeological framework of a complex fractured volcanic aquifer system in the Upper Awash River basin located at the western shoulder of the Ethiopian Rift. The groundwater flow system and mechanism of recharge of different aquifers have been studied using conventional hydrogeological field investigations, hydrochemistry, and isotope hydrology. Litho-hydrostratigraphic relationships were constructed from lithologic logs obtained from exploratory drilling of deep boreholes. The result indicates quite complex flow pattern and hydraulic characteristics of the different volcanic aquifers. The litho-hydrostratigraphic correlation indicates that the permeable and porous scoraceous lower basaltic aquifer is extended laterally all the way from the Blue Nile Plateau to the study area. New evidences have also emerged on the inter-basin groundwater transfer. Two distinct regional basaltic aquifers (upper and lower) are identified showing distinct hydrochemical and isotopic signatures. In the southern part of the study area the upper and lower aquifers form one unconfined regional aquifer system. In the northern and central part of the basin, it appears that the two systems are separated by regional aquiclude forming confined aquifers, in places with artesian wells. The groundwater from the deep exploratory wells (>250 m) tapping the lower basaltic aquifer and wells located in the south were found to be moderately mineralized (TDS: 400–600 mg/l), with relatively depleted stable isotope composition and with almost zero tritium. In contrast, the upper shallow aquifer has lesser ionic concentration, more isotopically enriched. Evidences from the different methods clearly indicate inter-basin groundwater transfer from the Blue Nile basin to the Upper Awash basin. The evidences also converge to testify common origin of recharge, presence of hydraulic connectivity for systems tapping the lower basaltic aquifer. This has enormous practical implication in finding large groundwater reserve at a greater depth that can solve the current water supply problems of the community including the capital Addis Ababa. It will also have important role in finding more regional aquifers along the plateau-rift margins in many areas having similar hydrogeological setup as the study area.

Summary Groundwater discharge from an esker aquifer to a fen was studied to understand relevant hydrological processes for groundwater-surface water interaction in an esker–peatland hillslope. Piezometric levels of the peat layer and esker sand layer were continuously monitored and compared to climate data. Groundwater exfiltration points were spatially mapped and related to peat depth. The study showed a clear interaction between fen surface water and sand esker groundwater although the hydraulic conductivity of peat was low and the peat depth thick. In the artesian aquifer beneath the fen, the piezometric head showed a clear response to precipitation and evapotranspiration. Wetting of the peat is rapidly seen as pressure increase in the confined aquifer. This provides new information on hydraulics of wetlands found in aquifer discharge areas. Groundwater exfiltrated through thick peat layers in vertical preferential point discharges demonstrating how double porosity provides flow through the peat layer with low hydraulic conductivity in the peat matrix. The “pipe flow” channels were found in the deep peat area in the transition zones from deep peat to shallow peat. Diffuse seepage through the ditch bottom was found where ditches cut into the sand layer. Increased discharge through the ditch bed reduced the flow resistance at the aquifer boundary which can lower the groundwater level in the esker. The results show new processes in the groundwater discharge zone that are useful for groundwater modelling and policy development for future groundwater protection.

Determining aquifer type, unconfined, semi-confined, or confined, by drilling or performing pumping tests has inherent problems (i.e., cost and complex field issues) while sometimes yielding inconclusive results. An improved method to cost-effectively determine aquifer type would be beneficial for hydraulic mapping of complex aquifer systems like fractured rock aquifers. Earth tides are known to influence water levels in wells penetrating confined aquifers or unconfined thick, low-porosity aquifers. Water-level fluctuations in wells tapping confined and unconfined aquifers are also influenced by changes in barometric pressure. Harmonic analyses of water-level fluctuations of a thick (~1000 m) carbonate aquifer located in south-central Oklahoma (Arbuckle-Simpson aquifer) were utilized in nine wells to identify aquifer type by evaluating the influence of earth tides and barometric-pressure variations using signal identification. On the basis of the results, portions of the aquifer responded hydraulically as each type of aquifer even though there was no significant variation in lithostratigraphy. The aquifer type was depth dependent with confined conditions becoming more prevalent with depth. The results demonstrate that harmonic analysis is an accurate and low-cost method to determine aquifer type.

The very diverse types of ground-water behavior in carbonate terrains can be classified by relating the flow type to a particular hydrogeologic environment each exhibiting a characteristic cave morphology. The ground water may move by diffuse flow, by retarded flow, or by free flow. Diffuse flow occurs in less soluble rocks such as extremely shaley limestones or crystalline dolomites. Integrated conduits are rare. Caves tend to be small, irregular, and often little more than solutionally widened joints. Retarded flows occur in artesian environments and in situations where unfavorable stratigraphy forces ground water to be confined to relatively thin beds. Network cave patterns are characteristic since hydrodynamic forces are damped by the external controls. Solution occurs along many available joints. Free flowing aquifers are those in which solution has developed a subsurface drainage system logically regarded as an underground extension of surface streams. These streams may have fully developed surface tributaries as well as recharge from sinkholes and general infiltration. Characteristic cave patterns are those of integrated conduit systems which are often truncated into linear, angulate, and branchwork caves. Free Flow aquifers may be further subdivided into Open aquifers lying beneath karst plains and Capped aquifers in which significant parts of the drainage net lie beneath an insoluble cap rock. Other geologic factors such as structure, detailed lithology, relief, and locations of major streams, control the details of cave morphology and orientation of the drainage network.

This study is an effort to trace the implication of tidal fluctuation on coastal groundwater quality for different aquifers in case of Saijo plain, western Japan, through major ion, heavy metal and isotopic chemistry as well as to estimate aquifer parameters by tidal response method. Time series analysis for chemical characteristics depicts that tidal fluctuation at diurnal basis significantly affects ionic signature of groundwater along with piezometric level for unconfined aquifer whereas effect is less prominent for confined aquifer. Different plots (e.g. 87Sr/86Sr vs 1/Sr and BEX vs Cl) were drawn in order to deduce mechanisms responsible for water quality change with tidal phase and it was found that cations exchange and local sea water–fresh water (SW–FW) mixing along with oxidation–reduction are likely to be main processes responsible for water quality changes. Using tide aquifer interaction technique, calculated hydraulic conductivities for different monitoring sites were 0.01 and 2.8 × 10− 6 m/s which appropriately address geological properties of aquifers, and thus it can be concluded that tide aquifer technique is a reliable technique to estimate aquifer properties.

We installed and operated a low-cost groundwater level observation system at intermittent hot spring wells in order to monitor volcanic strain signals from the active Meakan-dake volcano in eastern Hokkaido, Japan. Data are sampled at 1 Hz and are transmitted to the data center in real time. Evaluation of the water level time series with theoretical predictive tidal strain and coseismic static strain changes has suggested that the wells penetrate to the artesian aquifer and act as a volumetric strain sensor. An active earthquake swarm with more than 400 events occurred at the shallower part of the volcano from January 9 to 11, 2008. Three independent wells recorded pre- to co-swarm groundwater drops simultaneously, which represented a decrease in volumetric strain. The total volumetric strain change during the three active days was estimated to be from 6 to 7 × 10 − 7 . The observed data, including changes in volumetric strain, absence of deformation in the GPS coordinates, and activation of deep low-frequency earthquakes, might imply possible deflation of a source deeper than 10 km, and these preceding deeper activities might induce an earthquake swarm in a shallower part of the Meakan-dake volcano.

Groundwater is an important water resource in the Helwan area, not only for drinking and agricultural purposes, but also because several famous mineral springs have their origin in the fractured carbonate aquifer of the region. The area is heavily populated with a high density of industrial activities which may pose a risk for groundwater and surface water resources. The groundwater and surface water quality was investigated as a basis for more future investigations. The results revealed highly variable water hydrochemistry. High values of chloride, sulphate, hardness and significant mineralization were detected under the industrial and high-density urban areas. High nitrate contents in the groundwater recorded in the southern part of the study area are probably due to irrigation and sewage infiltrations from the sewage treatment station. The presence of shale and marl intercalation within the fissured and cavernous limestone aquifer promotes the exchange reactions and dissolution processes. The groundwater type is sodium, sulphate, chloride reflecting more mineralized than surface water. The results also showed that water in the study area (except the Nile water) is unsuitable for drinking purposes, but it can be used for irrigation and industrial purposes with some restrictions.

The quality of water from public drinking water supply system, from artesian wells in Kiev and bottled non-carbonated drinking water produced by various companies was investigated using a set of animal and plant test organisms. The integral index—a total toxicity index which allowed researchers to classify water into different categories from “safe” to “highly hazardous” served as a water quality evaluation criterion.

In Britain, groundwater abstraction from the confined region of an aquifer is less common than abstraction from the unconfined region. This paper describes how, during a study of abstraction from the confined region of the Woburn Sands aquifer in SE England, techniques were developed for examining the response of confined aquifers to pumping. Issues considered include the selection of both the extent of the aquifer system to be studied and the time period to be considered. Observation well records are examined to hypothesize how groundwater head hydrographs depend on abstraction and recharge. Another topic is the estimation of recharge when there is spatial variability in precipitation and when substantial areas of the aquifer are beneath low-permeability till. An approach is devised for river–aquifer interaction when the actual river channel is small compared with extensive river valley deposits. Conceptual and computational models are developed and evaluated against observation well hydrographs and single water-level readings at a number of locations. The computational model is used to ascertain how the flux from the unconfined to the confined region changes with variations in groundwater abstractions.

The Mornag coastal groundwater underlies the plain of this region. It is in northern Tunisia and 20 km SW of Tunis City. This region is known for its important agricultural activity. This aquifer is the main groundwater resource of the department of this region. To limit the overexploitation, there is a creation of some perimeters in the Naasen and Irrisala localities where wastewater is used. To maintain the hydrostatic groundwater balance, freshwater is injected (artificial refill). In the Nassen area treated wastewater irrigation is slowed and then stopped while the Irrisala perimeter is still irrigated by the same water type. To maintain hydrostatic equilibrium of the aquifer, water from the Mejerda Canal (M.C.) was injected. A geochemical study of the different parts of this groundwater is carried out, in order to clarify the salinisation origin and the hydrochemical evolution of the Mornag groundwater and to estimate the possible relationships between the natural processes (marine water intrusion), the water quality used either for irrigation or for artificial refill, and the geologic environment on the water quality of this aquifer. Its salinity, pH, temperature and electrical conductivity were measured and their respective averages are 3.1 g/l, 7.4, 18.7 °C and 4.4 mS/cm. The concentrations of sodium, calcium, magnesium, bicarbonate, chloride, sulphate, potassium and bromides were measured and their respective averages are 29.0, 15.1, 10.9, 4.8, 26.8, 10.5, 0.3 and 0.0482 mg/l. rMg 2+ /rCa 2+ and rBr − /rCl − ratios were calculated. The results suggest that the Mornag groundwater can be divided into 4 areas where the water chemistry depends on the natural processes and the water quality used for irrigation and artificial recharge: - for the coastal zone, marine water infiltration provokes the increase in salinity of this part of the aquifer; - infiltration of wastewater used for irrigation and run-off water resulted in changing geochemical water quality of these aquifer areas; - stopping of the use of wastewater, irrigation and artificial recharge water with good water quality did improve the aquifer water quality.

Summary Contamination of groundwater by intruding seawater is a major problem in many parts of the world. This work derives novel analytical solutions for addressing this problem by extending the Girinskii–Strack concept of discharge potential to represent regional, steady-state, sharp-interface seawater intrusion in a sloping unconfined coastal aquifer. The aquifer has hydraulic conductivity K, is recharged uniformly at the rate r, receives an inflow at its land boundary and has a collector trough (or well gallery idealised as line sink) located at the distance lw from the coastline that penetrates the aquifer and draws groundwater at the rate qw. The theory rests on the approximation of a linearised gravity-part of the hydraulic potential. Analytical solutions for the discharge potential are derived, through which the hydraulic head, the flow depth and the sharp interface, and particularly the location of the interface toe, lT, are also determined. These solutions simplify to known results for the horizontal aquifer case. The utility (and robustness to uncertainty regarding the base slope) of the results in applications is demonstrated in the regional example of the Akrotiri Coastal Aquifer, Cyprus. Recasting the problem in non-dimensional form provides a relationship for the dependence of the relative interface toe location lT/lw on the appropriately normalised difference between the groundwater flow just up-gradient of the collector trough, qo, and the pumping rate, qw, given values of the base slope, r/K and Hsea/lw, where Hsea is the sea-surface elevation above the aquifer base at the coastline. That relationship frames a common groundwater management problem in coastal aquifers subject to a certain exploitation scheme, with lT as decision variable. In an exploratory demonstration study, non-dimensional sets of performance curves are calculated for the regional Akrotiri aquifer. In general, the derived analytical solutions can be used for first-order assessments of seawater intrusion vulnerability and management possibilities across a wide range of current regional coastal aquifer conditions and/or projected water demand, groundwater management and climatic change scenarios.

Long-term excessive groundwater withdrawal causes severe land subsidence and considerable economic loss. During the period of land subsidence, aquifer sands present complex deformation characteristics. Field data in the Southern Yangtse Delta, China have shown that the deformation characteristics of aquifer sands are closely related to the changing patterns of groundwater level the aquifer units have experienced. When the groundwater level fluctuates yearly within a certain range, the aquifer unit behaves primarily as an elastic material. When the groundwater level rises and falls alternatively with the average decreasing but higher than the previous lowest value the unit has experienced, the aquifer unit behaves primarily as a visco-elastic and elasto-plastic material. However, when the average level decreases and is lower than the previous lowest value the unit has experienced, the aquifer unit behaves primarily as a visco-elastic, elasto-plastic, and visco-plastic material. The plastic and creep deformation of aquifer sands is also proved through laboratory tests. With the increasing cycle number of loading, the creep and plastic deformation decreases and the expansion under unloading is closer to the compression under loading in a single cycle. On the basis of field and laboratory data, a new mechanical model is constructed, which can describe various kinds of deformation characteristics under different changing patterns of groundwater level, including elastic, visco-elastic, plastic, and visco-plastic deformation. The model includes two yielding stresses and six parameters. When the appropriate field data are available, the six parameters of the model can be determined through graphic methods. Then the deformation of aquifer units can be calculated if the changing groundwater level is known.

The Neolithic site KS043, excavated by the Institut français d'archéologie orientale (IFAO), is situated in the southern basin of the Kharga Oasis (Egypt). It is one of the very few stratified prehistoric sites of the eastern Sahara. The archaeological remains were found near artesian springs that provided water for pastoralists during the dry Middle Holocene. In situ settlement features provided well-preserved material (charcoal, ashy sediment, ostrich eggshell) sufficient to perform radiocarbon dating in the IFAO laboratory in Cairo by the conventional liquid scintillation method. In 2 cases, ostrich eggshell and charcoal within the same in situ context gave significantly different results of, respectively, ∼600 and ∼1200 yr younger dates for the ostrich eggshells. The strong discrepancy is here highlighted for the first time and we suggest that it may be linked with postdepositional phenomena in the vicinity of the artesian springs. A thorough review of 14C dates available for the Holocene in eastern Sahara shows that ostrich eggshells have been widely used. They seem slightly more prone to be discarded than other material but were never the object of a particular study in this context. Bayesian modeling shows that the Neolithic occupation at site KS043 spans a range from 5000 to 3950 cal BC (and concentrated around 4600–4350 cal BC). Characteristic flint tools and pottery relate this occupation to the end of the Neolithic and show links with the Tasian culture, confirming the timing of the presence of this cultural complex in the desert before its appearance in the Nile Valley.

Yangqu River Coal Mine is located in the hydrogeological unit of the east of Gu Mountain. The groundwater system in this Mine includes quaternary pore aquifer group, fissure aquifer group of coal bed rock, fissure-karst aquifer group. The main aquifers include Shihezi sandstone confined aquifer, Middle Ordovician limestone fractured karst confined aquifer and the Upper Carboniferous in Taiyuan Formation thin-bedded limestone confined aquifer. The former is the main source of water-filled mine, and the later is the main aquifer to threat mining. The analysis of inrush water risk in 6# layer of Coal Mine determined the minimum elevation with pressure of exploitation. Through drainage experiments in Ordovician aquifer, mining methods are explored which are mining with pressure or mining with reducing the pressure in the “last three layers”. Through dynamic analysis of water quality in the coal mine, grasp the changes of aquifer salinity, and infer the natural recharge conditions in the aquifers. Detect water-rich region in advance for good hydrogeological forecast.

The deep and confined Maastrichtian aquifer contains considerable groundwater resources. It stretches over nearly 200,000 km2, from the northern part of Mauritania to the South of Guinea Bissau where it becomes shallow. The reservoir is composed mainly of coarse sands and sandstone interbedded with some clay units. The aquifer provides 40% of the total drinking water extracted from the different aquifers and nearly 800 wells equally distributed operate only in the top 50 m of the aquifer. Despite the importance of these resources for providing water in the rural and urban areas, the aquifer characteristics are not well defined. The present paper aims to define first the physical and chemical characteristics of the Maastrichtian aquifer. The reserve of the aquifer initially estimated at 350 billion m3, is reassessed using new data providing from cross sections realized as part of our research, through the Water Sectorial Project of the Ministry of Hydraulics. Data from oil wells and geophysical logging are used to investigate the geometry of the aquifer and the position of the fresh/salty water interface. The highest thickness of the aquifer is between 200 to 400 m and salty water is present below the fresh groundwater in the west side of the aquifer. In the Eastern side, potable water lies directly above the basement. The thickness of the aquifer increases from the west to the center, and then decreases towards the shallow basement rock in the South East. The average thickness is 250 m. Chemical data coming from pumping wells indicate high chloride (250 - 1600 mg/l) and fluoride content (1 - 5.5 mg/l). Therefore, the reassessment has to take into account the chemical aspect of the water.

From a water management perspective, the bulk quantity of water moved and where it has been sourced from are more important than simply estimating drawdown effects due to pumping. This note considers the problem of estimating the total quantity of water discharged between each aquifer in a multilayer aquifer model of Dudley Ward and Falle. Direct formulas are obtained in terms of the storativities and leakage coefficients. Assuming a typical disparity of scale between storativities of the phreatic aquifer and confined aquifers, type curves show that over time the vast majority of extracted water is sourced from the overlying phreatic aquifer.

The temperature inside wells used for gas, oil and geothermal energy production, as well as steam injection, is in general significantly higher than the groundwater temperature at shallower depths. While heat loss from these hot wells is known to occur, the extent to which this heat loss may result in density-driven flow and in mixing of surrounding groundwater has not been assessed so far. However, based on the heat and solute effects on density of this arrangement, the induced temperature contrasts in the aquifer due to heat transfer are expected to destabilize the system and result in convection, while existing salt concentration contrasts in an aquifer would act to stabilize the system. To evaluate the degree of impact that may occur under field conditions, free convection in a 50-m-thick aquifer driven by the heat loss from penetrating hot wells was simulated using a 2D axisymmetric SEAWAT model. In particular, the salinization potential of fresh groundwater due to the upward movement of brackish or saline water in a stratified aquifer is studied. To account for a large variety of well applications and configurations, as well as different penetrated aquifer systems, a wide range of well temperatures, from 40 to 100 °C, together with a range of salt concentration (1–35 kg/m3) contrasts were considered. This large temperature difference with the native groundwater (15 °C) required implementation of a non-linear density equation of state in SEAWAT. We show that density-driven groundwater flow results in a considerable salt mass transport (up to 166,000 kg) to the top of the aquifer in the vicinity of the well (radial distance up to 91 m) over a period of 30 years. Sensitivity analysis showed that density-driven groundwater flow and the upward salt transport was particularly enhanced by the increased heat transport from the well into the aquifer by thermal conduction due to increased well casing temperature, thermal conductivity of the soil, as well as decreased porosity values. Enhanced groundwater flow and salt transport was also observed for increased hydraulic conductivity of the aquifer. While advective salt transport was dominant for lower salt concentration contrasts, under higher salt concentration contrasts transport was controlled by dispersive mixing at the fresh-salt water interface between the two separate convection cells in the fresh and salt water layers. The results of this study indicate heat loss from hot well casings can induce density-driven transport and mixing processes in surrounding groundwater. This process should therefore be considered when monitoring for long-term groundwater quality changes near wells through which hot fluids or gases are transported.

Bosnia and Herzegovina, a country of Alpine orogene system, presents a terrain with a complex geological phenomenology and numerous mineral, thermal and thermomineral waters; there are 193 deposits of mineral, 57 thermal and 30 thermomineral waters with ca 400 natural springs and 170 drillholes and wells. The total yield of all deposits is 7,035 l/s, of which mineral waters contribute 4114 l/s, thermal 1828 l/s and thermomineral 1093 l/s. Drillings were performed in 50 deposits with natural springs and in 31 deposits without springs. Exploitation has been carried out in 47 deposits to establish the quality and quantity of these resources. The present use of mineral waters is in balneology, recreation, bottling and industrial use; thermal in balneology, recreation, bottling, water-supply, thermoenergetics and industrial use, and thermomineral in balneology, recreation, bottling, thermoenergetics and extraction of mineral raw materials. The total established power of 87 hydrogeothermal deposits is 251 MWt and potential power is ca 795 MWt with reference to 10 °C, while geothermal direct heat use is only about 22 MWt. Evidence clearly shows the potential of positive results of investigations and the sustainable and polyvalent use of these resources in numerous sites, though many obstacles make the feasibility of this application difficult. These waters are mostly renewable resources based on isotopic content and other data. There are a few waters of no meteoric origin in closed deep artesian horizons. All waters are dominantly prenuclear (“dead” waters—3H = 0). According to 14C content, a large number of waters are over 40,000 years old, with very slow circulation and long residence times in the aquifers, and they are naturally protected by insulating rocks as roof barriers to prevent any surface contamination of aquifers. Waters have various origins, content and concentration of constituents, and were formed in different rock ages and in complicated geological structures. There are specific waters of rare and effective physical and chemical composition which do not exist in surrounding countries. Mineral waters have a large range of TDS from 0.5 to 270 g/L, thermal from 0.15 to 0.8 g/L and the thermomineral from 1 to even 300 g/L; there is a great variety from the very acidic type (pH = 3) to hyperalkaline with pH = 12, with diverse contents of N2, O2, CO2, H2S composition with free and dissolved gases and different GWR. The CO2 in most of the carbon acid waters, according to δ13C in the CO2, is created at great depths and probably originates by thermal hydrolysis of marine carbonate rocks. In some deposits, the existence of higher homologues of methane and values of δ13C in CH4 indicate an organic origin of CH4 deriving from petroleum-gaseous deposits overlying ophiolitic rocks. Determining the plausible geological and geothermal models of terrain for the various types of groundwaters are basic theoretical and practical tasks, which allow the location of shallower wells for successful capturing of waters. Additional greater capacities of different groundwaters are possible to obtain by drillings of new deeper wells in almost all active mineral and hydrogeothermal deposits. It is of considerable interest to determine whether and in which sites and lithostratigraphic units there are as yet undiscovered hydrogeotherms of higher enthalpy in shallow and deeper horizons, particularly by investigating deposits with shallow drillings. Higher temperatures and greater yields have already been found in several deposits with shallow drillholes.

The search for geothermal resources for energy purposes began in the early 60s, based on a detailed geological program for hydrocarbon resources (that had extensive budgets). More than 250 wells have been drilled over the years, whose depths are between 800 and 3500 m. They revealed the presence of low-enthalpy geothermal resources (40–120 °C), which enabled the identification of many geothermal areas, most of them in the western part and three in the southern part of Romania. A recent study (involving the University of Oradea and Transgex S.A.) identified 223 wells drilled after 1965. The completion and experimental exploitation (part of geological investigations) of over 100 wells in the past 40 years enabled the evaluation of exploitable heat from geothermal reservoirs. More than 80 % of the wells are artesian producers; 68 of them (all the wells drilled in the Pannonian Basin) require anti-scaling treatment, and 4 are reinjection wells. The most comprehensive synthesis regarding the mineral and thermal waters of Romania belongs to Pricajan (Apele minerale si termale din România. Ed. Tehnica, Bucuresti, 1972) and Bandrabur et al. (Harta apelor mineral si termale din 420 România, scara 1:1.000.000, Atlasul Geologic. Ministerul Geologiei, Institutul de Geologie Si 421 Geofizica, Bucuresti, 1984). The work published by Pricajan (Apele minerale si termale din România. Ed. Tehnica, Bucuresti, 1972) contains a classification, from the chemical point of view, of the accumulations and occurrences of mineral waters into three major types: salted, sulfurous-sulfated and carbonated. A detailed hydrogeological description of the main accumulations of mineral waters (some of them with variable physical properties: thermalism, radioactivity), as well as their use, is also included.

The shallow Plio-Quaternary (PQ) water table, present over almost the whole Djerid and Chott El Gharsa basins (southern Tunisia), is used as a complement of oases irrigation, especially in summer season. The simplicity of the Plio-Quaternary lithology is confronted to the complexity of the mineralisation mechanisms and the water origin in this aquifer. An approach combining the use of water-dissolved chemical species and isotopic contents has been used to better understand the PQ behaviour under severe increasing exploitation and to determinate the origin of its different water bodies. In southern Tunisia, the aquifer system is composed of the upper unconfined PQ aquifer, the intermediate semi-confined/confined Complexe Terminal (CT) and the deeper confined Continental Intercalaire (CI). Chemical analyses highlighted an origin of mineralisation in close relationship to the dissolution of both sulphated salts (MgSO4 and Na2SO4) and chlorinated salts (NaCl and MgCl) abundant in the surface and subsurface gypsum crust. Positive correlations between gypsum anhydrite, mirabilite, thenardite and halite saturation indexes with respective mineral species, confirm evaporites dissolutions. Isotopic data showed that in addition of sporadic rainfall events, there is a contribution from the CI and the CT Saharan groundwaters, recharging the PQ aquifer in the study area. Return flow irrigation is partly affected by evaporation, before recharging the shallow aquifer, in oases limits.

The technology of aquifer thermal energy storage(ATES) is an energy-saving technology which can provide a solution to energy shortages and resources expasion. The first key point of this technology is whether the aquifer can be use to store energy. In this paper, taking Sanhejian Coal Mine as an example, we choose Quaternary upper loose sandy porosity confined aquifer to bottom clayed glavel porosity confined aquifer as aquifers thermal energy storage, to discuss whether the aquifers can be used to store energy. The simulation results of aquifer temperature field show that the selected aquifers reach the goal of energy storage. And with the same irrigation flow, the lower the temperature, the more the cold water and the larger the low temperature region in aquifers thermal energy storage. With the same irrigation temperature, the lager the irrigation flow the more the cold water and the larger the low temperature region in aquifers thermal energy storage.

A new analytical solution is developed for describing groundwater level fluctuations in a coupled leaky confined aquifer system which consists of an unconfined aquifer, confined aquifer, and an aquitard in between. The aquifer system has a tidal boundary at the seashore, a no flow boundary at remote inland side, and a confined aquifer extending under the sea and terminated with an outlet-capping. This new solution has shown to be a generalisation of most existing analytical solutions for a tidal aquifer system which includes single confined and leaky confined aquifers. In addition, the solution is used to explore the influences of the dimensionless leakance of the outlet-capping, the dimensionless hydraulic diffusivities, and the leakages of the inland and offshore aquitards on the head responses in the leaky confined aquifer.

Surface water bodies interact with underlying aquifer systems, creating a complex flow system and flow paths. In general, a surface water body may be classified as gaining, losing, or flow through on the basis of its interaction with the surrounding aquifer. In the Nile Valley, the quaternary aquifer system is in a direct hydraulic interaction with the River Nile, canals, and drains. In this study, a regional numerical model was developed and used to evaluate the interaction between surface water bodies and the quaternary aquifer system in the Nile Valley. The solution is considered for a quasi three-dimensional, steady-state groundwater flow. The model used simulates the interaction between surface water bodies and groundwater for saturated and unsaturated flow conditions. In addition, a hydrodynamic model was used to simulate different extreme (high and low) scenarios for Nile surface water levels along the distance between Old Aswan Dam and Delta Barrages. Model calibration shows close results, and the model was used to simulate surface water levels. Results indicate that the Nile River acts as a drain for the quaternary aquifer (gaining water from the aquifer), although in the reaches upstream of the main barrages, the Nile loses the water, recharging the aquifer. All other main canals are recharging the aquifer system. The seepage rate depends mainly on the difference in piezometric head between the aquifer system and surface water bodies, as well as the hydraulic conductance of the base layer sediments of the surface water body. The model was used to evaluate the regional water balance for the Nile Valley and to estimate the surface water bodies' gains and losses.

More than 100 regional groundwater depression cones have developed because of groundwater over-exploitation in recent years in China. The total area of the cones is nearly 15 × 104 km2 and the Daqing groundwater depression cone considered in this paper is the second largest. In order to control groundwater level and its related environmental side effects, artificial aquifer recharge (AR) will be implemented in the Daqing groundwater depression cone. Recharge water imported from the River Nenjiang will interact with native groundwater and the aquifer matrix during the process of artificial aquifer recharge and this will influence groundwater quality and affect the groundwater environment in the region. The interaction between recharge water, native groundwater and aquifer matrix was forecast by groundwater geochemistry modelling. The modelled results show a tendency of water quality change in aquifer, which is helpful to identify any health risks and assess the feasibility of artificial recharge in this region of China.

We consider the case of pumping a semiconfined aquifer overlain by a phreatic aquifer hydraulically connected to an infinitely long and straight stream. The hydraulics of the system are described by a linearized model in which it is assumed that flow in the aquifers is essentially horizontal, and that drawdown in the phreatic aquifer is small enough to allow the water table to be sufficiently well described by the Theis equation. Fourier-Laplace transforms of drawdown are obtained and numerically inverted. Comparisons are made with another well-known analytic model of Hunt, who considered a single aquifer/aquitard system. It is observed that while both models may have excellent agreement during the initial phase of pumping, the longer-term consequences of sustained pumping are quite distinct.

The current study aimed to evaluate hydrogeologically the Nubian sandstone aquifer in El-Bahariya Oasis. It represents the main water-bearing horizon in the study area and consists of continental elastic sediments, mainly sandstone alternating with shale and clays. The general flow lines are directed from SW to NE direction, as detected from the constructed potentiometric head contour map. The piezometric surface reaches 149 m in El-Heiz area at the southern part, while it reaches 90 m at the northern, reflecting higher pressure head of the aquifer in the southern part. The map also illustrates that the southern part is considered as the most promising location for development. The structural elements play an important role in the deposition and distribution of the sedimentary succession of the Nubian sandstone sediments. Consequently, this sedimentary pattern affects the occurrences and movements of the groundwater within the aquifer system. Along the structurally high areas, in the study area, the piezometric head increases, while the reverse is recorded along the structurally low areas. The step-drawdown tests data were carried out by calculating the aquifer loss coefficient (B) and the well loss constant (C). The B values are smaller compared with C values, indicating that the aquifer under pressure has a behavior of leaky aquifer; therefore, it shows hydraulic connection with surrounding formation. The values of well efficiency range from 78.50% to 87.76%. Analysis of 12 pumping test data (constant discharge tests) was carried out in order to calculate the Nubian aquifer hydraulic parameters (transmissivity, hydraulic conductivity, and storage coefficient). The transmissivity values decrease from 3,045 m2/day in the southern part (El-Heiz area) to 236 m2/day in the northeastern part (El-Harra area). Accordingly, the aquifer classified as a high to moderate potentiality. Transmissivity contour map observes gradual increase of transmissivity values from the southern to northeastern direction. This may be due to the increase of shale or clay content in the concerned aquifer in that direction. The storage coefficient values range between 1.04 × 10−4 and 5.22 × 10−3, as obtained from the results of pumping test analysis, which ensure that the Nubian sandstone aquifer is classified as semi-confined to confined aquifer type. The S values show a decrease from southwest to northeast direction as detected from S-map. The hydraulic conductivity values vary from to 0.46 m/day in the northern part to 10.88 m/day in the southern part with an average of 5.67 m/day. According to the classification based on K values, the aquifer is mainly composed of coarse sand.

Analysis of tidal effects on aquifer systems plays an important role in coastal aquifer management owing to various hydrological, engineering and environmental problems in coastal areas. Using the real-world data of unconfined and confined aquifers, a data-driven approach is presented in this study for the analysis of tide–aquifer interaction in coastal aquifers. Six analytical tide–aquifer interaction models were selected which take into account the effects of vertical beach, sloping beach, tidal loading, aquifer leakage, outlet capping, and combined leakage and outlet capping on tide-induced groundwater fluctuations. The tide–aquifer interaction datasets were obtained from the Konan groundwater basin (unconfined aquifer) of Japan and the Dridrate groundwater basin (confined aquifer) of Morocco. The analysis of the results obtained by the sloping beach model revealed that for a given beach slope, the amplitude of groundwater level increases with an increase in aquifer diffusivity and a decrease in aquifer thickness. However, no significant effect of beach slope was observed in this study at unconfined sites for all the datasets. The influence of tidal loading was found to be considerably less for all the three confined sites. Further, the analysis of the results of the leakage model indicated that with an increase in leakage into the aquifer, the amplitude of groundwater level as well as the phase shift (time lag) decreases. Of all the confined and unconfined datasets, only two confined sites were found to be affected by outlet capping. Overall, it is concluded that the coastal beach bordering the Konan basin is not significantly sloping, the contribution of tidal loading to tide-induced groundwater fluctuations in the Dridrate aquifer is not appreciable, and that the aquifer leakage and outlet capping do not exist at the unconfined sites under investigation.

Drawdown cone volume of pumping well reflects the hydro geological conditions of aquifer, such as hydraulic parameters and elastic storage for confined aquifer. During later period of pumping test in non-leaky confined aquifer, the relationship between drawdown and distance appears as straight line in plots figure, and the relationship between drawdown and time appears as straight line in plots figure. Based on Theis solution, through analyzing of the slope of curves , and integrating, volume of drawdown cone of pumping well in non-leaky confined aquifer was derived in this paper.

The groundwater of Rrogozhina aquifer (western Albania) is generally characterized by high iron contents. Its water-bearing medium consists of soft to hard sandstone and conglomerate with intercalations of impermeable clay layers. The groundwater of Rrogozhina aquifer, that extends over a surface of 2100 km2 in the pre-Adriatic depression of Albania, occurs under typically artesian conditions. The iron content in ground water ranges from 0.2% up to 2.5%, but most of them fall within the interval 0.5-1.0 %. In groundwater iron occurs as reduced divalent ferrous iron (Fe+2) which is conditioned by the lack of water exposure to oxygen and the long residence time of the groundwater. Iron is more frequent in sandstone related groundwater as it is shown by the positive correlation between the iron content in groundwater and sandstone thickness in the section. The predomination of iron-bearing minerals such as magnetite, epidote, granate, sphene, amphibole and pyroxene in the silt fraction indicates that it must be responsible for the iron content in groundwater.

Summary A low-permeability weathered siltstone–sandstone aquifer containing brackish water was investigated to measure recoverability of injected freshwater with the aim of determining the significance of secondary porosity in contributing to groundwater flow and transport. Examination of the core, borehole geophysics, Radon-222, electromagnetic flowmeter (EMF) profiles and step-drawdown pumping tests did not identify whether fractures contribute to groundwater flow. A number of injection and recovery tests lasting from 3 days to 3 months using potable water showed a large degree of mixing with native groundwater. Withdrawal greater than 12–17% of the injected volume resulted in recovered water containing more native groundwater than injected water. A finite element solute transport model was set up to reproduce the observed salinity in recovered water. Without the inclusion of discrete fractures in the model it was not possible to get a fit between the observed and modelled salinity of recovered water within a realistic range of dispersivity values. The model was subsequently verified by using data from long-term injection and recovery trials. This evaluation of mixing conclusively demonstrated that the aquifer behaved as a fractured rock aquifer and not as an aquifer with primary porosity alone. Therefore, aquifer storage and recovery can be a very useful hydrogeological method to identify the occurrence of fracture flow in aquifers where there is a measurable concentration difference between the injected water and ambient groundwater.

Gafsa region is one of the most productive artesian basins in Southern Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. Proper understanding of the geochemical evolution of groundwater is important for sustainable development of water resources in this region. A hydrogeochemical survey was conducted on the Plio-Quaternary shallow and on the Complex Terminal aquifers system using major (Ca, Mg, Na, SO4, Cl, NO3 and HCO3) and minor (Sr) elements, in order to evaluate the groundwater chemistry patterns and the main mineralization processes occurring in this system. Hydrochemical and isotopic data were used in conjunction with hydrogeological characteristics to investigate the groundwater composition in these aquifers. It has been demonstrated that groundwaters acquire their mineralization principally by water–rock interaction, i.e. dissolution of evaporites (halite/gypsum, pyrite, etc.) and return flow of irrigation waters, and by anthropogenic activities due to the use of nitrogen (N) fertilizers–pesticides in agriculture. The isotopic study of “stable isotopes, radiocarbon and tritium” (Yermani 2002) shows that a paleoclimatic recharge is corroborated by the relatively low carbon-14 activities (5–25.3%) of the referred groundwater group samples, which were interpreted as recharge occurring during the late Pleistocene and the early Holocene periods. The water feedings of these aquifers are mainly provided by infiltration of precipitations, infiltration of irrigation water, lateral feeding from Cretaceous relieves from the South and the North and along recent and fossil drainage networks that constitute major freshwater sources in groundwater tables (Hamed et al., J Environ Protect 1:466–474, 2010a).

The section of the upper Rio Grande in New Mexico is important to downstream water management and the administration of water rights. It has long been believed that this remote reach of the Rio Grande is characterized by significant groundwater accretions, which contribute to water available for downstream uses. This study focused on the uppermost 30 miles of the Rio Grande in New Mexico seeking to establish locations of groundwater accretions in the reach and document magnitude of gain. In order to quantify the accretion of the upper Rio Grande, an expedition using inflatable kayaks, an acoustic Doppler current profiler (ADCP) and an electromagnetic meter was carried out in the fall of 2008 when natural surface flow was low. The study area covered a stretch of 31 miles. The expedition was able to determine that the total accretion of this stretch of the Rio Grande was 22 ft3s−1 with an average accretion rate of 0.73 ft3s−1 mile−1. Most of the reach exhibited minimal gain or loss, and most of the accretion was centred in Sunshine Valley. One of the most significant results was encountering a large artesian, subaqueous spring, which might be the largest documented spring in New Mexico and contributes nearly 50% of the accretion in the reach. The study was also able to characterize the exact locations of other significant groundwater inputs. In addition to quantifying the accretion of part of the upper Rio Grande, the study provides the framework for using advanced technology in the form of an ADCP to determine river accretions in remote locations. ADCPs offer the benefit of reducing measurement time and measurement error, collect high-resolution data and are non-intrusive. Overall, the use of ADCP technology to determine river accretion offers an improvement over traditional methods, and it is the hope of the authors that this technology is utilized for river accretion studies in the future. Copyright © 2011 John Wiley & Sons, Ltd.