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The article discusses papers which have been awarded with the Best Paper 2011 Awards by the journal. Awarded papers include "Producing more food with less water in a changing world: assessment of water productivity in 10 major river basins," by Xueliang Cai and colleagues; "Managing buried treasure across frontiers: the international Law of Transboundary Aquifers," by Gabriel E. Eckstein, and "Hydrosolidarity and beyond: can ethics and equity find a place in today's water resource management?"

This paper reports the dynamism of a submarine groundwater discharge (SGD) zone in SW India. Two electrical resistivity tomography (ERT) surveys were conducted in the project area to delineate the seawater-fresh water interface and characterize the subsurface aquifer layers. Beach groundwater dynamics were also studied by continuously monitoring salinity, temperature, and nutrient concentration in the groundwater from three shallow dug wells on the beach. The ERT surveys were planned in such a way as to fall between these dug wells. The flow domain was modeled using a numerical modeling approach, and the rate of fresh SGD flux and its spatial variation along the coastline has been estimated. The study proves that the numerical modeling approach combined with other field measurements and observations, such as ERT and continuous monitoring gives a comprehensive understanding of SGD and associated processes. [ABSTRACT FROM AUTHOR]

Water banking in aquifers is an internationally proven, low-cost solution that could improve drought resilience across the Murray Darling Basin. While significant potential for water banking through managed aquifer recharge (MAR) or conjunctive use of surface and groundwater resources has been identified in the Murray Darling Basin Plan, there is a need to establish clear policy and institutional foundations to incentivise adoption. To provide appropriate incentives for schemes, the legal status of rights to recharge, store and recover water, and the rules and costs which apply to groundwater extraction need to be clear and transparent. This paper aims to clarify principles and frameworks to secure water rights for recharge, storage, and recovery within the sustainable limits of water resources currently set under law. The current Basin Plan supports water banking, and banking would be complementary with objective and outcomes sought by future Basin Plans. Existing water accounting systems would need to accommodate this new capacity. Institutional arrangements and financial structures of water banking in the USA provide guidance for Australia. Demonstration sites would enable concurrent policy development and institutional set-up and provide critical experience to serve as models for wider adoption as part of future Murray Darling Basin plans. [ABSTRACT FROM AUTHOR]

The Macta River basin in Algeria is under pressure. A water accounting of the basin demonstrates the severity of the crisis, with a net water depletion rate estimated at 93–142%, depending on the assumptions made. This reflects the overexploitation of the aquifers whose annual depletion is estimated at between 86 and 126 Mm3. This paper first discusses the causes of basin overbuilding and the over-allocation of water, and then analyses the economic, social and environmental consequences. It calls for a stricter water accounting of river basins in Algeria as the 2030 Agenda for Sustainable Development and its SDG 6 are implemented. [ABSTRACT FROM AUTHOR]

Deep beneath the surface of the continent, memories of the ancient Eromanga Sea are retained in subterranean aquifers and the veins of opal that flash above them in lithic fissures. The excavation of these hidden resources has been critical to the advancement of establishing the settler-colony, Australia, and in perpetuating the ongoing violence of Indigenous dispossession. In this paper, I examine the entangled subterranean figures of aquifers and opals as they surface in the Australian literary archive. I read early twentieth century representations of groundwater usage and opal mining communities in works by Banjo Paterson and Katharine Suzannah Prichard against contemporary evocations of these themes in novels by Janette Turner Hospital (Oyster) and Tara June Winch (Swallow the Air). In doing so, I explore the challenges of representing, reading and interpreting deep watery spaces. [ABSTRACT FROM AUTHOR]

Groundwater is a major source of water supply and supports many ecosystems in sub-Saharan Africa. According to Integrated Water Resources Management principles, institutionalizing groundwater management and transboundary aquifer cooperation within lake and river basin organizations has long been on the agenda. Although progress has been made at the institutional and operational levels over the last decade, the capacity of these organizations has not been structurally augmented. While this calls for broad structural changes, a few practical solutions are proposed, such as hiring hydrogeologists in regional institutions, adopting open water data policies, and prioritizing intervention areas in transboundary aquifers. [ABSTRACT FROM AUTHOR]

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This paper summarizes the results of a study focused on the hydrogeological characterization and recognition of groundwater resources in continental southern Italy, developed under the European INTERREG IIC Programme. The study reconstructed up-to-date scientific knowledge regarding aquifers, groundwater circulation schemes and groundwater resources exploitation in the administrative regions of southern Italy included in the Objective I (Molise, Campania, Basilicata, Puglia and Calabria). In this paper, the methodological approaches applied to synthesize and homogenize bibliographic data collected from the hydrogeological literature and to set a regional hydrogeological mapping are described. Results presented are three hydrogeological maps, 1:300,000 scale, showing hydrogeological units and groundwater flow schemes that are relevant in the regional hydrogeological context, and a brief description of principal types of aquifer and groundwater resources of continental southern Italy. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive semi-distributed water balance model is presented for basins under anthropogenic impacts. It benefits from data in different time resolutions for estimation of surface and groundwater exchanges and water withdrawals for various purposes. Ground-based data such as vegetation cover and topography have been used to determine the model parameters. The performance of the proposed model was tested for 38 sub-basins in Iran representing various climate conditions, vegetation covers, and agricultural practices. The results demonstrated a good performance in terms of estimating streamflows at the basin outlet, with more than 90% of sub-basins having a correlation coefficient above 0.9. However, the model showed a relatively weaker performance in the estimation of annual aquifer storage volume change. Correlation coefficients above 0.6 were calculated for more than half of the aquifers in the study area. [ABSTRACT FROM AUTHOR]

Excessive groundwater exploitation in Sirjan plain, located in south of Iran, has caused severe land subsidence. The main purpose of this paper is to determine the hydrogeological parameters of the aquifer system in Sirjan plain. To this end, the groundwater flow was simulated in both steady and transient states using the United States Geological Survey Modular Three-Dimensional Finite-Difference Groundwater Flow Model, MODFLOW. The hydraulic conductivity parameter of the aquifer system was first estimated and calibrated in the steady state by simulating the hydraulic head at 63 piezometric wells. The specific yield and recharge parameters were then calibrated in the transient state by simulating the drawdown within a period of interest, i.e. 23 September 2004 to 22 September 2005. The main innovation of this paper, however, is to use the potential of Synthetic Aperture Radar (SAR) interferometry time-series analysis in the last step of the proposed algorithm. Small Baseline Subset (SBAS) time-series analysis was applied using Envisat Advanced SAR (ASAR) images acquired from 1 June 2004 to 28 September 2010. The merit of SBAS time series is that it enables us to calculate the amount of subsidence in each period of interest while minimizing the temporal decorrelation effect. In the last step, the SBAS time-series analysis results were obtained to extract the accumulated subsidence from 19 October 2004 to 30 August 2005. The aquifer compaction due to this period was calculated in the Interbed Storage Package (IBS1) for MODFLOW in order to calibrate storage coefficient in a trial-and-error manner so as the calculated subsidence and the observed one by SAR interferometry be in a good agreement. The Root Mean Square Error (RMSE) between the simulated subsidence and the observed one is calculated as 0.019 m which is an indication of the high performance of modelling. [ABSTRACT FROM AUTHOR]

This paper describes the spatial and temporal variability of the hydrogeochemistry of shallow aquifer in the western Po Plains, located in Piedmont (northwestern Italy), using groundwater monitoring network data for the main chemical--physical parameters. Hydrochemical maps for the 2015-2020 period were created to identify the main natural and anthropogenic factors responsible for the remarkable spatial variability. Temporal variations in the 2000-2020 period were defined to show the existence of variabilities that were previously not investigated. The spatial and temporal elaborations show significant and various variabilities. The hydrochemical maps confirm the existence of several natural and anthropogenic factors, including the lithological compositions of aquifers, agricultural practices and pressure from urban centres. The temporal variations suggest different resilience capacities of the aquifers to the several impacting factors. The availability of this knowledge is crucial to create the basis for groundwater protection. [ABSTRACT FROM AUTHOR]

Hydrogeological mapping is a key tool for groundwater resource management. Generally, hydrogeological maps focus mainly on porous or karst aquifer at large scale. In a fractured-rock aquifer, the groundwater flow path is not immediately deductible due to the intrinsic complexity of fracture systems. Then, it is of crucial importance collecting a complete dataset describing the site of interest: fault and strata patterns, geomorphological features, occurrence of springs. Here we present the hydrogeological map at 1:10,000 scale of the fractured rock aquifer of Conglomerate of Portofino (Italy). The graphical information contained in this map is based on the authors' field survey and the revision of papers written for academic purposes and technical reports. The aim of the research is to achieve a useful tool for land planning, conservation of groundwater resource and geo-hydrological risk reduction in the unique area of the Natural Park of Portofino. [ABSTRACT FROM AUTHOR]

The paper presents a series of maps on the Western Mancha aquifer, an aquifer of 5,500 km2, extending over an area of 41 villages in the region of La Mancha, in the central Spanish plateau. Maps were produced using cartograms, which highlight the differential groundwater use at the local level of the municipality, looking at equity and efficiency issues related to groundwater. The main purpose of the paper is to provide comprehensive, transparent and easily understandable mapping of groundwater use in a region where data is abundant but not necessarily consistent, clear or presented in an easily accessible or understandable format. The paper provides a meta-analysis in the form of maps of available data as a result of a large number of European research projects, national and European policy initiatives, but where a general multi-disciplinary and summative overview is still lacking. This mapping can contribute to decision making in public policy, as support for compliance with the European UnionWater Framework Directive on good ecological status, in an area where there are competing, and in many ways incompatible, water demands between irrigation and wetlands. This analysis highlights that a spatially differentiated approach could provide win-win scenarios, i.e. intensive groundwater use and wetland protection. [ABSTRACT FROM AUTHOR]

The Guaraní Aquifer System (SAG) is the largest transboundary aquifer in Latin America, extending beneath parts of Brazil, Paraguay, Argentina, and Uruguay. This paper presents the results of recent hydrogeological studies in the southern portion of the SAG. Locally, the abundance of surface water bodies precluded the use of conventional hydrological tools to characterize groundwater flows. Geological, hydrochemical and environmental isotope investigations were integrated to postulate a revised hydrogeological conceptual model. The revised geological model has provided a better definition of the geometry of the aquifer units and outlined the relevance of regional faults in controlling flow patterns. The new potentiometric map is consistent with groundwater flow from the SAG outcrops to the centre of the Corrientes Province, where upwards flows were identified. Hydrochemical and isotope data confirmed the widespread occurrence of mixing. Noble gas isotopes dissolved in groundwater (4He and 81Kr/Kr) provided residence times ranging from recent recharge up to 770 ± 130 ka. Groundwater age modelling confirmed the role of the geological structures in controlling groundwater flow. The southern sector of the SAG is a multilayer aquifer system with vertical flows and deep regional discharge near the Esteros del Iberá wetland area and along the Paraná and Uruguay rivers. [ABSTRACT FROM AUTHOR]

Water from the alluvium of ephemeral rivers in Zimbabwe is increasingly being used. These alluvial aquifers are recharged annually from infiltrating floodwater. Nonetheless, the size of this water resource is not without limit and an understanding of the hydrological processes of an alluvial aquifer is required for its sustainable management. This paper presents the development of a water balance model, which estimates the water level in an alluvial aquifer recharged by surface flow and rainfall, while allowing for abstraction, evaporation and other losses. The model is coupled with a watershed model, which generates inflows from upland catchment areas and tributaries. Climate, hydrological, land cover and geomorphological data were collected as inputs to both models as well as observed flow and water levels for model calibration and validation. The sand river model was found to be good at simulating the observed water level and was most sensitive to porosity and seepage. [ABSTRACT FROM AUTHOR]

This paper deals with the inverse problems of wells' location and transmissivity estimation in a saturated porous media. Wells are considered as circular holes and the heterogeneous domain is divided into zones with constant transmissivity in each one. The main used tool for wells' location is the topological gradient method applied to a design function defined with respect to available data. Moreover, this technique is incorporated in an adaptive parameterization algorithm leading, in a progressive way, to recover interfaces between hydrogeological zones and transmissivity values. The obtained algorithm allows to recover jointly the transmissivities and the wells' locations. Then the proposed method is tested on a simplified model inspired from the Rocky Mountain aquifer. [ABSTRACT FROM AUTHOR]

Pumping tests in aquifers separated by semipervious layer are generally analyzed by using solutions for leaky aquifers that assume constant head distribution in the unpumped source bed. This may not be true under prolonged pumping. Hantush (1967) solutions take into account head decline in the unpumped source bed. The objective of this paper is to present procedures for pumping test analysis using some of these solutions. Both type curve matching and straight-line methods have been presented. Procedures described in this paper can be used to analyze early-time drawdown data of the pumped aquifer and the late late-time drawdown data of the pumped and unpumped aquifer above the semipervious layer. The hydraulic properties for the pumped and unpumped aquifer and the semipervious layer estimated by different methods are quite comparable. [ABSTRACT FROM AUTHOR]

Analysis of hydrogeological data of aquifers requires assessment of multiple variables and this is difficult to visualise in a single map with commonly used techniques. Ring maps are presented in this paper as a useful option to overcome this limitation. Four alluvial aquifers from Central Italy were assessed and are presented as case studies, evaluating the hydrogeological setting, the groundwater chemistry and the distribution of representative contaminants (Boron, Iron, Manganese and Nitrates). The final result is a graphical representation showing the ring maps, which simultaneously depict 12 numerical variables and two other variables: the geographical position and the main lithological properties of the aquifers. The research indicates that coastal alluvial aquifers show higher contamination when compared to the intramontane alluvial aquifers. Boron is exclusively present in the coastal alluvial aquifers where maximum concentrations are associated with the uprising of deeper saline groundwater with a chloride-sodium chemistry. Iron and manganese are generally associated and their presence is inversely correlated to that of nitrates. The presence of Nitrates is less common in the intramontane aquifers. The ring maps presented in this paper have been effectively used as a geovisualisation tool for multivariate hydrogeological and environmental data. The technique simultaneously and clearly shows several variables in one single graphical representation. [ABSTRACT FROM AUTHOR]

The safety of aquifer gas storage (AGS) depends on the mechanical stability of the caprock to a great extent. The injection and production operation of AGS will cause the disturbance of the in-situ stress due to the change of pore pressure in the reservoir and caprock, which may lead to the failure of caprock. The con AGS is established based on geological structure and hydrogeological information. By using the finite element method, the factors such as boundary condition, properties of reservoir and caprock, and in-situ stress coefficient are considered, respectively, and the variation of formation pressure and disturbed stress in the process of injection and production are analyzed. The results show that the boundary conditions are of significant influence on the stress field. The shear failure risk of reservoir–caprock interface under closed boundary is the greatest. The in-situ stress coefficient has the greatest influence on the failure risk of the caprock, followed by the permeability of the reservoir and caprock. [ABSTRACT FROM AUTHOR]

Desalination plants employing feed water sourced from saline groundwater (SGW) are a feasible approach to tackle freshwater scarcity and seawater intrusion (SWI). Available studies lacked comprehensive analysis quantifying the impact of pumping from a coastal aquifer, on changes in solute transport mechanism. This study investigates the impact of different rates of SGW pumping on the solute transport in a coastal aquifer. A regional-scale model resembling the Upper Floridan aquifer was modelled using SEAWAT to quantify SWI variables. The study found that the length of intrusion of toe (Ltoe), width of mixing zone (WMZ) and residual salt mass (RSM) varied with dispersivity values. The ratio of saltwater to freshwater influx was unaffected by dispersivity values. Significant decrease in the toe-length occurred when the pumping rate was highest and the dispersivity was lowest. The WMZ was found to be the most sensitive SWI variable towards varying dispersivity, with 65% difference for higher pumping rates. The mid-bottom region was experiencing substantial modifications, leading to an inclined response at increased pumping rates, which suggested that the diluting process was primarily taking place in the bottom portion. This study gives insight into saline wedge movement in a coastal aquifer system which will benefit in the design of SGW well system for desalination plants. [ABSTRACT FROM AUTHOR]

The focus of this paper is the Nubian Sandstone Aquifer System, shared by Egypt, Chad, Sudan and Libya, and the agreements and other instruments of cooperation in place among the four countries. These combined instruments bear witness to an evolutionary pattern of cooperation, centred on procedural norms and on a joint institution. In the author's opinion, the four countries should strive to attain a more mature level of cooperation covering substantive norms and the settlement of disputes. The author recommends the UN Draft Articles on the Law of Transboundary Aquifers (2008) as a basis for such an agreement. [ABSTRACT FROM AUTHOR]

Research was conducted by the author and an inter-disciplinary team at Al Akhawayn University, Morocco, under a Canadian (IDRC) grant between 2009 and 2011. Using various methodologies, including survey research, the team found several significant obstacles facing the diffusion of drip irrigation technology in the Middle Atlas region of Morocco. These obstacles include lack of access to capital, land titles that cannot be mortgaged, and a weak presence of the relevant bureaucracies at the farm level. The implications of these obstacles in terms of responding to climate change and aquifer depletion are addressed as part of the paper. [ABSTRACT FROM PUBLISHER]

The hydrogeology of the municipalized territory (13,210 km2) of the Saguenay-Lac-Saint-Jean (SLSJ) region has been studied as part of the groundwater knowledge acquisition program entitled Programme d’acquisition de connaissances sur les eaux souterraines (PACES) launched in 2008 by the Government of Quebec, Canada. This study involved the collaboration of numerous contributors (municipal policymakers, government agencies, watershed organizations and universities) to meet the program’s multiple and wide-ranging requirements. The key deliverables included a numerical geodatabase, 38 regional-scale maps and a scientific report, all elaborated after 4 years of data gathering and compilation, fieldwork and information synthesis. In addition, numerous collateral research projects were undertaken by undergraduate and graduate students. The results of the SLSJ-PACES project provided new insights into regional groundwater resources and led to a generalized conceptual model of regional hydrostratigraphic features and groundwater quality. This paper summarizes the particular aspects of the major aquifers in the SLSJ region as uncovered by PACES, and presents the emerging challenges for updating and improving the region’s hydrogeological knowledge and ensuring the sustainable management of regional groundwater resources. [ABSTRACT FROM AUTHOR]

Overexploitation of groundwater resources in coastal regions is a wide-spread phenomenon, especially in arid and in semi-arid regions, which may lead to deterioration and abandonment of coastal aquifers, due to saltwater intrusion. Development of mathematical and numerical models to describe fresh and salt water flow and to optimise groundwater development systems is essential for the protection and sustainable use of coastal aquifers. In this paper, we present applications of two different models that predict saltwater penetration in a coastal region, due to the operation of a production well. The well is located in an aquifer with different zones of hydraulic conductivity. The first model-SISWIM is a finite difference two-phase flow model, based on the assumption of a sharp interface between salt and fresh water, while the second one, is a simplified surrogate flow model based on the boundary element method. The aim of this paper is to compare the results and to explain the importance of having detailed information about hydraulic conductivity distribution in designing the sustainable exploitation of coastal groundwater systems. [ABSTRACT FROM PUBLISHER]

This paper examines the legal and ecological problems facing the Guarani Aquifer System. Because the majority of the Guarani Aquifer System underlies Brazil, the Brazilian legal regime forms the paper's principal focus. The importance of the region makes the need for accurate information crucial. Yet relying on such information to manage a complex resource presents risks. Too often, the role of uncertainty in regulating is underplayed. Increasing knowledge over the resource demands categorizing 'hard' and 'soft' uncertainties, especially those presented by climate change. In addition, regulators must acknowledge the unitary nature of the aquifer while remaining sensitive to differing national priorities. [ABSTRACT FROM AUTHOR]

Current water use in the areas of Israel, Gaza, West Bank and Jordan is not consistent with a sustainable water supply: growing demands relative to supplies threaten underground aquifers, and water quality problems diminish the health and welfare of current residents and impair future water supplies. A hydro-geologic system can be viewed as a commons that provides a stream of benefits to an entire geographic area over time. Sustainability requires the design of new institutions with appropriate boundaries and rules. This paper proposes a regional cooperative management system, combining aspects of a regional utility and a joint commission, which would use price incentives for management purposes. The non-profit regional water utility would establish limits on water use, determine water prices and make investments from system revenues. For efficiency, surface water, groundwater and recovered water of the same quality should receive the same price. Withdrawal limits based on sustainability would be sufficient to establish prices through the interaction of supply and demand. Equity issues could be addressed by a guaranteed water provision with a relatively low price for the guaranteed level. Security in terms of adequate groundwater storage could be achieved through appropriate investment. A representative body of water users would help the utility determine appropriate limits and guarantees. The conceptual basis for this institutional design is temporal efficiency. While a traditional market could improve spatial allocation, it would not necessarily address sustainability or provide for investment in recycling and other technologies to improve water supply. Furthermore, the proposed system bypasses the issue of property rights required for full market exchange. [ABSTRACT FROM AUTHOR]

The paper examines the success of Israeli farmers in retaining their political clout at a time when their sector was shrinking. Comparing differing explanations, it is shown that since the 1970s farmers' effective rent seeking explains their success in an ongoing political struggle – mainly against the Ministry of Finance – to buy water at subsidized rates. The characteristics of Israeli farmers' successful rent seeking are portrayed, and the logic behind success is analyzed. Finally its consequences – directly influencing income distribution, and indirectly contributing to aquifer depletion and desalination postponement – are examined. [ABSTRACT FROM AUTHOR]

This paper analyses one of the essential aspects of water pricing, which is the mechanism on the basis of which appropriate water charges could be levied. This is why, in matters of water pricing, the question of 'quantum' is still a subject of consideration. The diversity of the results is often simply due to the specific regions or basins, or even rivers, lakes or aquifers, of the country. In other words, the diversity will occur according to the natural differences between bulk water markets, and not because of the existence of many different methodologies for water pricing. [ABSTRACT FROM AUTHOR]

With an extension of 1.2 million square kilometers, the Guarani Aquifer System is one of the largest transboundary groundwater systems in the world. It underlies parts of Argentina, Brazil, Paraguay, and Uruguay and was only relatively recently recognized as a transboundary resource. The four countries are now in the process of starting up a project to elaborate and implement a common institutional and technical framework for managing and preserving the Guarani Aquifer System for current and future generations. This paper briefly presents the Guarani Aquifer System Project. The preparation process is described due to its particular interest for other similar multi-country endeavors. Following the presentation of the project, the paper takes a forward-looking approach and analyzes the applicability of current international law for transboundary groundwater resources in the context of the Guarani Aquifer System. It concludes that while the basic principles espoused by international law relating to transboundary groundwater resources management are valid, they do not provide very specific guidance. The Guarani Aquifer System is unique and its complex features make it an eclectic case, which already is obliging all stakeholders to work out innovative measures — in the legal, institutional, technical, scientific, social, and economic realms — to develop appropriate activities for its sustainable management. [ABSTRACT FROM AUTHOR]

This paper presents a method to estimate the long-range dependence and multifractality in data on porosity observed at two separate locations of a saltwater monitoring network. The method is useful in the classification and clustering of the network. [ABSTRACT FROM AUTHOR]

The need for joint management of increasingly stressed cross-boundary aquifers is likely to grow in upcoming years. Yet there is a lack of experience in the management of cross-boundary groundwater. Moreover, the differences in the nature of groundwater and surface water preclude direct transfer of experience gained in managing cross-boundary rivers and lakes to the management of cross-border groundwater basins. This paper suggests an open-ended approach to the identification of joint management structures for shared aquifers to overcome the inability to rely on prior experience. A flexiblesequential framework is proposed that allows the parties to identify and evaluate options not tried before. The discussion is on the most salient points for analysts and decision-makers. The framework is developed within the Israeli-Palestinian context; however, the approach is applicable to a wider array of situations. [ABSTRACT FROM AUTHOR]

Chile's approach to water management, based on a private property regimen combined with a period of extreme drought, had led to the overexploitation of groundwater. To address this issue, groundwater communities have formed and implemented management actions beyond the functions assigned to them by law. This article focuses on the experience of groundwater communities in the Copiapó Aquifer in Chile, highlighting their innovative actions such as incorporating environmental protection goals, promoting participation in decision-making, facilitating temporary water transfers, and conducting studies for improved management. The adaptive capacity demonstrated by groundwater communities shows the potential for innovation in Chilean groundwater management. [ABSTRACT FROM AUTHOR]

This article discusses the governance aspects of managing river, lake, and aquifer basins, both at the transboundary and domestic levels. It highlights the importance of basin organizations in facilitating negotiation, data sharing, and decision-making among stakeholders. The article also explores the challenges faced by international basin organizations, such as power asymmetries and the inclusion of non-state actors. Additionally, it examines the scale implications of transboundary agreements and the participation of civil society in water management. The article concludes by emphasizing the need for improved institutions and cooperation in order to effectively manage water resources. [Extracted from the article]

The paper evaluates the relationships among invertebrate communities, land uses and chemical and microbiological groundwater properties, in a loessic unconfined aquifer in Argentina. Two surveys were conducted and seven wells were selected based on land use and unsaturated zone (USZ) thickness. Groundwater was characterized mainly as freshwater of sodium bicarbonate type. Invertebrates collected belong to Crustacea, Acari, Insecta, Collembola, Oligochaeta, Collembola, Pauropoda, and Nematoda. Crustacea was the most abundant group. The wells differed in terms of invertebrate composition and abundance. The lowest abundance was observed at sites with thickest USZ. No direct relationship was found between invertebrate abundance and any particular physicochemical parameter. In the only well where bacteria were detected, total invertebrate abundance, especially of copepods, was high in both surveys. Both USZ thickness and land use have a significant influence on abundance and composition of invertebrate communities in terms of organic matter inputs into the aquifer. [ABSTRACT FROM PUBLISHER]

Determination of the hydraulic properties of a coastal aquifer system with lower cost and acceptable accuracy has practical implications. Although many theoretical solutions have been developed over recent decades, most of them assume that an aquifer system extends inland and subjected a single-frequency tidal fluctuation on coastline boundary. In addition, only one hydraulic parameter, i.e., the hydraulic diffusivity, of an aquifer can be obtained in most cases. In this paper, the solution of groundwater response in a leaky confined coastal aquifer to dual frequency tidal fluctuations has been established. The new solution was then used as an example to discuss the applicability and limitations of using tidal fluctuations for determining coastal aquifer hydraulic properties. Our study illustrated that ocean tides could only transport to a limited distance towards inland depending on the coastal aquifer hydraulic properties. The tidal method is applicable only when changes in the hydraulic head within in a monitoring well can be detected with an acceptable accuracy. Both the hydraulic diffusivity and leakage can be identified from the monitored hydraulic heads. By incorporating the use of aquifer thickness, the transmissivity and storage coefficient of a perfectly confined aquifer can also be simultaneously estimated. [ABSTRACT FROM AUTHOR]

This Special Issue illustrates the use of environmental isotopes in studying and assessing hydrogeological and ecohydrological issues in the Latin America and the Caribbean (LAC) region. In many parts of the LAC region, groundwater resources have become the main or the only source of water to cover basic human needs and the maintenance of ecosystems [[8]]. I Land-water interactions i (EH): Vegetation cover aids to protect soil surface from erosion, whose rates can be estimated by using radioactive isotope ( SP 7 sp Be) techniques [[27]]. First snow, glacier and groundwater contribution quantification in the upper Mendoza River basin using stable water isotopes. [Extracted from the article]

A simple and novel ultrasonically modified dual-cloud point extraction (Um-DCPE) method has been developed to preconcentrate a toxic heavy metal, lead (Pb2+), in aquifer water of different depths in the region of Thar coalfield, Pakistan, prior to analysed by flame atomic absorption spectrometry (FAAS). The Pb2+ in water samples have been complex with 8-hydroxyquinoline followed by the entrapping in the hydrophobic non-ionic surfactant (Triton X-114). The second step of Um-DCPE involved the addition of 0.5 to 2.0 mol L−1 of HCl/HNO3 (2 mL) and subjected to shaking and centrifugation, separate upper aqueous layers, and subjected for analysis. To check the performance of the proposed method a certified reference material (CRM) of water and spiked standard in a real sample were applied successively. Both LOD and LOQ achieved by the proposed method for Pb2+ were 0.023 and 1.70 μg L−1, respectively. The optimised Um-DCPE method was applied effectively to selected aquifer water samples. The results obtained from the proposed method indicated that the aquifer water samples of different depths have 2 to 3 folds higher Pb2+ values than recommended values of the world health organisation. [ABSTRACT FROM AUTHOR]

Sorption is a necessary process influencing the subsurface solute or contaminant transport. There are many adsorption isotherms, and selecting one to represent the system is likely to remain an elusive goal. Also, the lack of observed data and its associated certainty may hinder the determination of sorption parameters. This study investigated the influence of different isotherms – linear adsorption assumption, Freundlich isotherm, Langmuir isotherm, and Redlich – Peterson isotherm, on chloride concentrations. The numerical model also gauged the extent of recharged waters migrating from the injection well. Temporal analysis of groundwater resident volumes helped to understand better the change in chloride concentrations with the selected isotherm. The residual solute concentrations from the isotherms followed the order: Redlich – Peterson < Freundlich < Langmuir. The results highlighted the importance of obtaining a range of sorption values rather than a single value from one fitted isotherm for the productive aid in groundwater decision making. [ABSTRACT FROM AUTHOR]

The Waterloo Moraine provides a major source of drinking water to the Region of Waterloo and supports many important ecological features throughout the area. As such, the structure of the multi-aquifer system of the Waterloo Moraine has been the topic of technical and scientific studies over the last 50 years. As additional data were collected and investigative tools were developed, the conceptual stratigraphic and hydrogeologic models were updated and refined. A strong correlation exists between the stratigraphy and the hydrostratigraphy within the Waterloo Moraine, and stratigraphic models have largely provided the framework for hydrogeological investigations. The current hydrostratigraphic framework within the Waterloo Moraine was developed through refinement of a stratigraphic framework using water level data, hydraulic response data, geochemical data and geophysical data collected in boreholes and monitoring wells located across the Region of Waterloo. Water supply aquifers are found throughout the stratigraphic sequence, including coarse-grained sediments within, and beneath, the Waterloo Moraine. Shallow coarse-grained unsaturated deposits and hummocky terrain of the central core area of the Waterloo Moraine allow large volumes of recharge to infiltrate, and this water is subsequently transmitted to deeper aquifer aquifer units through erosional windows in the aquitards. One of the most productive aquifers within the Region is located in the basal sediments of the Waterloo Moraine, while other thick and transmissive aquifer units underlie these moraine sediments. This paper describes the past and current studies that contributed to a refined understanding of the hydrogeology of the Waterloo Moraine and its underlying sediments. Discussion focuses on the municipal water supply aquifers and the potential linkages between municipal aquifers and environmental features, such as cold-water streams and wetlands that are reliant on groundwater discharge for ecosystem health. Understanding these linkages is particularly important given the forecasted population growth and increased municipal demand in the Region of Waterloo in the coming decades, and the need to protect the municipal water supply aquifers and sensitive surface water features. La moraine de Waterloo est une source importante d’eau potable pour la région de Waterloo et elle assure de nombreuses fonctions écologiques dans toute la région. Par conséquent, la structure du système multi-aquifère de la moraine de Waterloo a fait l’objet de nombreuses études techniques et scientifiques au cours des 50 dernières années. Avec la collecte de données additionnelles et le développement d’outils d’analyse, les modèles hydrogéologiques et stratigraphiques conceptuels ont été actualisés et raffinés. Il existe une forte corrélation entre la stratigraphie et l’hydrostratigraphie de la moraine de Waterloo, et les modèles stratigraphiques ont largement fourni le cadre des études hydrogéologiques. Le développement de l’actuel cadre hydrostratigraphique de la moraine de Waterloo a consisté à raffiner le cadre stratigraphique grâce à des données sur les niveaux d’eau, des données sur la réponse d’essais hydrauliques, des données géochimiques et des données géophysiques recueillies dans des forages et des puits de surveillance dans la région de Waterloo. Les aquifères utilisés pour l’approvisionnement en eau potable sont répartis dans toute la séquence stratigraphique, dont les des sédiments à grains grossiers à l’intérieur de la moraine de Waterloo et sous celle-ci. Des sédiments non saturés et peu profonds à grains grossiers et du terrain bosselé dans la partie centrale de la moraine de Waterloo permettent l’infiltration d’importants volumes d’eau de recharge qui s’infiltre subséquemment vers les unités aquifères plus profondes par des fenêtres d’érosion dans les aquitards. Un des aquifères les plus productifs dans la région se trouve dans les sédiments à la base de la moraine de Waterloo alors que d’autres unités aquifères épaisses et transmissives se trouvent sous ces sédiments morainiques. Dans cet article, nous décrivons les études passées et actuelles qui ont contribué à mieux comprendre l’hydrogéologie de la moraine de Waterloo et ses sédiments sous jacents. L’article décrit les aquifères servant à l’approvisionnement municipal en eau potable et les liens possibles entre ces aquifères et les entités environnementales, comme les cours d’eau et les zones humides qui sont alimentés par la décharge des eaux souterraines assurerant ainsi la santé des écosystèmes. Comprendre ces liens est de la première importance, compte tenu des prévisions de croissance démographique et de demande municipale accrue dans la région de Waterloo au cours des prochaines décennies, et de la nécessité de protéger les aquifères servant à l’alimentation municipale en eau, ainsi que les eaux de surface sensibles. [ABSTRACT FROM AUTHOR]

Nogales, Sonora, on the US–Mexico border, employs interbasin water and wastewater transfers to address water scarcity in the context of a rising population, a warming climate, and cross-border institutional asymmetries. A unique feature of its geography and border context is Nogales's export of wastewater both north to the US and, starting with the August 2012 commissioning of a strategically positioned wastewater treatment plant, south to the Alisos basin, which is its principal drinking-water source. Thus, when the new plant is fully operational, it will result in indirect potable reuse of effluent via recharge of the source-water aquifer. This paper finds that such strategies contribute to increased water scarcity in Nogales, and to detrimental health, livelihood and environmental impacts in the source basin, thus raising questions about interbasin transfers as a principal water management strategy. [ABSTRACT FROM AUTHOR]

In the global crisis over access to clean, adequate freshwater, Africa is a special case. Not only are many African states under severe water stress, but the continent is one of the most hydrologically interconnected regions on the planet. With 113 rivers, lakes and aquifers that cross an international border, over 60% of Africa’s territory falls into a transboundary watershed. Africa’s hydrology is interdependent, and mass poverty and political volatility heighten the risk of conflict over freshwater resources. This paper compares two approaches to understanding the severity of transboundary freshwater conflict; one based in behavior and the other based on structural factors unique to each water resource and its users. The goal is to identify Africa’s water hot spots, or those areas where violence over water resources is most likely. The broader aim is to better understand how the way we measure severity affects our understanding of freshwater conflict, and how policy-makers might best approach water politics in Africa. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The vertical heterogeneity of contaminant concentrations in aquifers is well known, but obtaining representative samples is still a subject of debate. In this paper, the question arises from sites where numerous fully screened wells exist and there is a need to define the vertical distribution of contaminants. For this purpose, several wells were investigated with different techniques on a site contaminated with chlorinated solvents. A core-bored well shows that a tetrachloroethene (PCE) phase is sitting on and infiltrating a less permeable layer. Downstream of the cored well, the following sampling techniques were compared on fully screened wells: low flow pumping at several depths, pumping between packers and a new multilevel sampler for fully screened wells. Concerning low flow rate pumping, very low gradients were found, which may be due to the existence of vertical flow inside the well or in the gravel pack. Sampling between packers gave results comparable with the cores, separating a layer with PCE and trichloroethene from another one with cis1,2-dichloroethene and vinyl chloride as major compounds. Detailed sampling according to pumped volume shows that even between packers, cleaning of the inter-packer volume is necessary before each sampling. Lastly, the proposed new multilevel sampler gives results similar to the packers but has the advantages of much faster sampling and a constant vertical positioning, which is fairly important for long-term monitoring in highly stratified aquifers. [ABSTRACT FROM AUTHOR]

Conjunctive use of surface and groundwater through managed aquifer recharge (MAR) is underway in Australia, principally to reuse urban wastewater. The opportunity for MAR in farming landscapes has received less attention, and the extent this might occur using water from large flood events or dam releases has not been examined. This paper addresses that gap by providing an overview of the potential benefits and challenges to implementing MAR using water from large floods, examining the social acceptability of MAR amongst groundwater licence holders in the Namoi Valley, and identifying future research needed to assess this opportunity. The appeal of MAR using water from large flood events is the opportunity it affords to replenish aquifers, return linkages between depleted groundwater and surface flows, and buffer the impacts of drought on irrigators and aquatic ecosystems. Most of the respondents to the Namoi survey agreed that MAR has merit. However, some research informants were concerned about the impact of recharge on groundwater quality and the possibility that MAR would be another intervention that would lead to over-exploitation of a scarce resource. A number of ways to implement MAR using large flood events are also canvassed and we identify next steps for the assessment of those options. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geological layers often have different hydraulic conductivities. This paper presents an innovative design for delivering aqueous substrates and nutrients to various stratified layers at desired rates during in-situ bio-stimulation. The new delivery system consists of intermittent porous tubes connected in series with impermeable polyethylene tubes that run horizontally in each stratified layer of a contaminated aquifer. Results of the tracer test indicated that the distribution of tritium through each porous tube was fairly uniform. A mathematical model was also developed to calculate the distribution of water flow through each porous tube. By controlling the permeability and the length of porous tubes placed in stratified layers, the new design provides a means to selectively deliver nutrients to various layers at desired rates according to aquifer heterogeneity. [ABSTRACT FROM PUBLISHER]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Protection of clean aquifers requires radical minimization of water consumption, overall reduction of wastewater and, furthermore, minimization of wastewater loading. Many organic pollutants in wastewater present a specific problem because of their toxicity, bioaccumulation and poor biodegradability. The scope of this paper is to investigate and identify the benefits offered by advanced oxidation processes (AOPs) as destructive methods for treatment of wastewater loaded with recalcitrant organic pollutants. The study was performed on model wastewater containing p-chlorophenol as a representative of organic chemical industry intermediates. Several UV based AOPs were studied: UV, UV/H 2O 2, UV/O3, UV/H 2O 2/O 3 and UV/Fenton. Optimal process conditions for the highest mineralization efficiency in the investigated range (pH, [H 2O 2] and [Fe 2+]) have been determined on the basis of HPLC measurements and the following ecological parameters: total organic carbon (TOC), adsorbable organic halides (AOX), chemical oxygen demand (COD) and biochemical oxygen demand (BOD 5). Toxicity is one of the most important ecological parameters in determining the level of water pollution. In this study, toxicity tests were performed on the zooplankton Daphnia magna in order to evaluate efficiency of the applied treatments. The UV/ Fenton and UV/H 2O 2/O 3 processes were found to be the most appropriate processes for degradation and mineralization of p-chlorophenol. Complete degradation was achieved after 15 minutes of UV/Fenton process treatment, while 92.1% TOC and 98.3% AOX removals were obtained after treatment of 60 minutes. [ABSTRACT FROM PUBLISHER]

The article discusses identifying aquifers with effective management around the world with including finding of aquifers with great success in Southern California, needs of growing urban population, and legal adjudication of the aquifer.

Modelling time series of groundwater levels is investigated by three fuzzy logic (FL) models, Sugeno (SFL), Mamdani (MFL) and Larsen (LFL), using data from observation wells. One novelty in the study is the re-use of these three models as multiple models through the following strategies: (a) simple averaging, (b) weighted averaging and (c) committee machine techniques; these are implemented using artificial neural networks (ANN). These strategies provide some evidence that (i) multiple models improve on the performance of individual models and those using committee machines perform better than the other two options; and (ii) committee machine models produce defensible modelling results to develop management scenarios. The study investigates water table declines through management scenarios and shows that in this aquifer water use has higher impacts on water table variations than climatic variations. This provides evidence of the need for planned management in the study area. [ABSTRACT FROM AUTHOR]