Tracer methods have been widely used in many fields of environmental and natural sciences, and also in human health sciences. In particular, tracers are used in the study of karst hydrogeology, typically focusing on phenomena such as sinkholes, sinking rivers and large karst springs. It is known that tracers have been used since antiquity. The aim of tracer tests has been to investigate underground

The terrestrial subsurface acts as a buffer in regulating land-surface water and energy processes. In integrated modeling with land-surface models, the regulating capacity of the subsurface is largely determined by the bottom boundary condition placement (BBCP). However, the sensitivity of land-surface processes to BBCP in Earth system modeling and integrated hydrologic modeling under conditions of

Understanding the influence of river-water infiltration on groundwater is essential for effective management of groundwater resources adjacent to a losing river. This study evaluates the influence of river-water infiltration in the alluvial fan of the Nalenggele River basin, northwest China, using (1) spectral analysis to analyze river discharges and groundwater levels, and (2) environmental tracers

A Correction to this paper has been published: https://doi.org/10.1007/s10040-020-02296-7

Karst aquifers are highly susceptible to pollution transport, particularly turbidity, because these aquifers do not filter water to any significant degree. This may occasionally induce sanitary issues for the population and, therefore, it is operationally important to predict the mobility of water with high turbidity. In this study, deep specific architectures, recurrent and feed-forward, inspired

The distribution and flow of groundwater in karstified rocks can be extremely complex and not readily predictable, a far from friendly environment for constructing dams and reservoirs. There have been many expensive failures such as unacceptable leakage rates at and around dams, and/or reservoirs that could not be filled to the design levels. This is never the fault of site geology but always of human

South-central Kentucky (USA) has one of the world’s most intensively studied karst landscape/aquifer systems, including the carbonates that hold the Mammoth Cave System. Slightly higher in the Mississippian (Lower Carboniferous) stratigraphic section, the Haney Limestone forms a locally important but much less well-studied karst aquifer. This research provides the most comprehensive synthesis to date

The Luxembourg Sandstone is the main strategic aquifer of the Grand-Duchy of Luxembourg, providing one third of the total drinking water resource in the country. In the unconfined part, the aquifer discharges through more than 400 springs, which are used for supply. The long-lasting diffuse contamination by pesticides (more recently Metolachor ESA) has been previously simulated assuming the aquifer

A laboratory analogue experiment platform with an artificial fracture was built to analyze the effect of slug interference tests on the evaluation of the hydraulic properties of fractured rocks. The response of an aquifer to a slug source well was analyzed using type-curve comparisons under the condition of different radial constant-water-head boundaries. The injecting-water, releasing-water, and pneumatic

A groundwater recharge investigation in the arid zone of Australia is presented. The investigation used a wide range of hydrogeological techniques including geological mapping, surface and borehole geophysics, groundwater hydraulics, streambed temperature and pressure monitoring, and hydrogeochemical and environmental tracer sampling, and it was complemented by analysis of rainfall intensity from 18

Accurate estimation of irrigation return flow plays an important role in the effective management of groundwater, especially in arid and semiarid irrigation regions. However, there is a lack of sufficient research to clarify hydrological process dynamics associated with irrigation return flow. In this study, first, a two-dimensional/three-dimensional model, HYDRUS-2D/3D, was adopted to analyze two

Changes in groundwater recharge associated with variations in land use were analysed with a focus on the role of afforestation on the east coast of Buenos Aires, Argentina. The growth of the population related to such changes was considered, linking water consumption to variations in recharge. A multi-temporal analysis was carried out using aerial photographs for the years 1957, 1975, 1981 and 2016

Master recession curves of 117 karstic springs from Middle and Upper Triassic carbonate aquifers in the Slovakian territory of the mountainous Western Carpathians were assembled from gauged discharge data. Identified slow-flow and fast-flow components were very diversely represented. Fast-flow components were missing in 47% of springs. In another 20% of springs, only fast-flow components were recognized

This work describes the geochemical and hydrogeological characteristics of Santa Cesarea Terme, an active sulfuric acid speleogenetic system located along the Adriatic coastline (Apulia, southern Italy). It represents a very peculiar site, where rising thermal and acidic waters mix with seawater creating undersaturated solutions with respect to CaCO3, able to dissolve and corrode limestone and create

Single-borehole dilution tests (SBDTs) are a method for characterizing groundwater monitoring wells and boreholes, and are based on the injection of a tracer into the saturated zone and the observation of concentration over depth and time. SBDTs are applicable in all aquifer types, but especially interesting in heterogeneous karst or fractured aquifers. Uniform injections aim at a homogeneous tracer

Several different approaches have been developed to model the specific characteristics of karst aquifers, taking account of their inherent complex spatial and temporal heterogeneities. This paper sets out the development of a semidistributed modelling approach for applications in an Irish karst context using urban drainage software. The models have proven to be very useful for different studies, with

The Bayesian approach is attractive because it can consider various uncertainties in the inverse process. Although the Bayesian algorithm has strong random ergodicity, it still lacks the ability to perform local optimization. Therefore, an improved single-component adaptive Metropolis (SCAM) algorithm based on Bayesian theory was developed to solve this problem and it was applied to the simultaneous

In southwestern Bangladesh, clean drinking water is scarce, since rainwater is only available during the monsoon, pond water is often bacteriologically polluted, and groundwater may exhibit high salinity and arsenic levels. Managed aquifer recharge (MAR) might potentially provide safe drinking water by storing abundant freshwater from the wet season in aquifers for year-round use. Regional potential

The Chari-Logone watershed is the only hydrologically active part of the Lake Chad Basin (Central Africa). The Chari-Logone River and Lake Chad exchange water with the surrounding unconfined aquifers of sedimentary and crystalline rock types. In this study, the groundwater contribution to stream flow was quantified by taking advantage of a comprehensive hydrological and chemical database from the 1970s

Processes in coastal aquifers involving variable-density fluids are often investigated using laboratory sand tanks. However, experimental monitoring of the interface between liquids of different densities is challenging, typically requiring dye tracers and photographic analysis. These are susceptible to problems of tracer adsorption and image inhomogeneity, and experiments are often limited to two-dimensional

Numerical modeling of karst water systems is a challenge due to vastly different flow regimes in the solution channels and the porous medium, and because of the complex interactions between them. Recent developments with unstructured grid models have enabled robust simulation of such systems due to full coupling of the system of equations and the interactions, within a flexible gridding framework that

The Commission on Karst Hydrogeology, also known as the Karst Commission (KC), was founded in 1970 in Neuchâtel, Switzerland, and it is an important part of the International Association of Hydrogeologists (IAH). The general idea was to organise a group of hydrogeologists from different countries, with relevant experience in karst hydrogeology, to promote cooperation among scientists interested in

Parameter estimation with uncertainty quantification is essential in groundwater modeling to ensure model quality; however, parameter estimation, especially for non-Gaussian distributed parameters in highly heterogeneous aquifers, is still a great challenge. The ensemble smoother with multiple data assimilation (ES-MDA) is one of the most popular and effective ensemble-based data assimilation algorithms

This study compares and analyzes high-frequency hydrochemical data from three karst catchments in the mountainous Gadenalpe (GAC, Austrian Alps), Tsanfleuron-Sanetsch (TSC, Swiss Alps), and Banzhai (BZC, SW China) regions, to differentiate the effects of temperature, runoff, and land-cover on carbonate weathering. The results show that when bare rock dominates in the recharge area, as in the GAC and

The permeability of carbonate aquifers varies widely, but the major factors that influence changes in permeability with depth are not well established. Trends in permeability and solute concentration data were analysed for four carbonate aquifers where data were available over a wide range of depths. The Deep Geologic Repository (Ontario, Canada), Edwards Aquifer (Texas, USA), and Chalk aquifer (England

Combining the results obtained by hydraulic (hysteresis) and hydrochemical (multivariate statistical analysis) approaches gives a better understanding of karst aquifer behavior, functioning of the hydraulic barrier and hydrogeochemical processes. The hydraulic approach is based on the principle that the relation of the groundwater levels in piezometers and the water level in a surface-water reservoir

Groundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency

Imaging characterization of a heterogeneous alluvial aquifer at a decametric scale is presented. The characterization relies on responses to oscillatory pumping tests led in two different wells and at two different periods of oscillation (5 and 10 min). These specific oscillatory responses are extracted from the hydraulic pressure values, measured in 13 boreholes during the pumping tests, through a

The Nairobi volcano-sedimentary regional aquifer system (NAS) of Kenya hosts >6 M people, including 4.7 M people in the city of Nairobi. This work combines analysis of multi-decadal in-situ water-level data with numerical groundwater modelling to provide an assessment of the past and likely future evolution of Nairobi’s groundwater resources. Since the mid-1970s, groundwater abstraction has increased

Interaction between surface water and groundwater plays a fundamental role in influencing aquatic chemistry, where hyporheic exchange processes, distribution of flow paths and residence times within the hyporheic zone will influence the transport of mass and energy in the surface-water/groundwater system. Geomorphological conditions greatly influence hyporheic exchange, and heterogeneities such as

A wide variety of well drilling techniques and well completion methods is used in the installation of dewatering and artificial recharge wells for the purpose of construction dewatering. The selection of the optimal well type is always a trade-off between the overall costs of well completion and development, the optimal well hydraulics of the well itself, the hydraulic impact of the well on its surroundings

Notable delay of more than 1 year (12.5–15.9 months) between precipitation recharge and groundwater-level upturn was recorded in the Triassic karstic aquifer of the Kopa Mt. (1,187 m asl) in the middle of the West Carpathians in Slovakia. The velocity of recharge transit (0.24–0.70 m/day) was affirmed by borehole hydrographs. The groundwater level here is deep (113–300 m below ground surface) but approximately

Karst aquifers are characterized by high-conductivity conduits embedded in a low-conductivity fractured matrix, resulting in extreme heterogeneity and variable groundwater flow behavior. The conduit network controls groundwater flow, but is often unmapped, making it difficult to apply numerical models to predict system behavior. This paper presents a multi-model ensemble method to represent structural

The Yucatán Peninsula karst aquifer in southeastern Mexico is important because it is the only source of freshwater supply in the region. Along the eastern coast, the aquifer behaves as a shallow unconfined aquifer, and one of its main characteristics is the development of a complex network of karstic conduits. Electrical resistivity tomography (ERT) is a geophysical technique that provides reliable

Management of coastal groundwater must take account of the complex hydrological processes and uncertainties associated with this environment. Regular evaluation of mechanisms, parameters and boundary conditions is required to understand groundwater flow and to develop a robust conceptual model. In certain conditions, as in tropical regions, due to the high intensity and variability of natural drivers

Potential effects of projected climate variability on base flow and groundwater storage in the North Fork Red River aquifer, Oklahoma (USA), were estimated using downscaled climate model data coupled with a numerical groundwater-flow model. The North Fork Red River aquifer discharges groundwater to the North Fork Red River, which provides inflow to Lake Altus. To approximate future conditions, Coupled

Groundwater is an important global resource and its sustainable use faces major challenges. New methods and advances in computational science could lead to much improved understanding of groundwater processes and subsurface properties. A closer look at current groundwater monitoring practice reveals the need for updates with a special focus on the benefits of high-frequency and high-resolution datasets

Karst aquifers are very easily contaminated because of the surficial features that commonly exist in karst terranes. Pollutant releases into sinkholes, sinking streams, and/or losing streams commonly result in concentrated solutes rapidly infiltrating and migrating through the subsurface to eventually discharge at downgradient springs unless intercepted by production wells, but slow percolation through

In karst catchments where only sparse temporal monitoring is performed, it is generally difficult to correctly assess the overall hydrodynamics of the basin. However, sparse temporal spring-discharge data may contain information of major importance for the characterization of such catchments, especially when sparse spring-discharge data over a long period are available and combined with higher frequency

Injection of silicate grouting materials is widely used to create temporary horizontal layers for reducing inflow of groundwater at construction sites, in regions with shallow water tables. The erosion of a grouting layer was investigated by means of analytical solutions for groundwater flow and transport within a pit after construction finished. Erosion is assumed to occur by dissolution of the temporary

The original version of this article was revised due to a retrospective Open Access order.

In three-dimensional (3-D) implicit geological modeling, the bounding surfaces between geological units are automatically constructed from lithological contact data (position and orientation) and the location and orientation of potential faults. This approach was applied to conceptualize a karst aquifer in the Middle Triassic Muschelkalk Formation in southwest Germany, using digital elevation data

Nitrate pollution from agricultural sources is one of the biggest issues facing groundwater management in the European Union (EU). During the last three decades, tens of nitrate vulnerable zones (NVZ) have been designated across the EU, aiming to make the problem more manageable. The Gallocanta Groundwater Body in NE Spain was declared as an NVZ in 1997, and after more than 20 years, significant improvements

Comprehensive aquifer characterization requires the development of a three-dimensional (3D) geological model and estimation of hydraulic and hydro-geochemical properties. This can be used to discern the governing processes of groundwater flow and chemistry, and plan pertinent groundwater management approaches. This study evaluated the influence of geological settings and groundwater flow on the groundwater

In South Transdanubia (Hungary), the remarkable geothermal and hydrocarbon resources in the Drava Basin and the hypogene caves at the margin of outcropping carbonate hills were usually investigated separately and their interactions were hitherto neglected. The aim of this study is to give all these groundwater-related resources and phenomena a common framework applying the concept of regional hydraulic

During construction dewatering, artificial recharge with wells might be required to discharge the pumped groundwater. On the one hand, artificial recharge wells must be placed as close as possible to the construction site to limit the above-ground space for the dewatering infrastructure and the transport costs, while on the other hand, the distance from the dewatering site must be considerably large

Floodplains are often conceptualized as homogeneous sediment bodies which connect streams with their respective catchment and buffer agricultural inputs. This has led to a general bias within the hydrological community towards research on sites where the floodplain is a clear conduit for groundwater flow. In humid temperate regions of central Europe, floodplains have experienced rapid environmental

An experimental investigation of seepage characteristics in porous rocks with a single fracture is presented. A seepage system was developed and assembled in the laboratory using two experimental setups. Tests were conducted to quantify the effects of influent pattern, fracture aperture (B), coefficient of permeability of the porous medium (k), hydraulic gradient (J), and water temperature (T) on the

Infiltration from natural rivers or streams is the most important source of aquifer recharge at riverbank filtration (RBF) sites. Due to the influence of river hydrological processes and changes in suspended solids in rivers, riverbed sediments often undergo significant flushing and clogging processes, which lead to obvious spatial and temporal changes in riverbed sediment permeability. Moreover, the

Pilot Valley is an 828-km2 arid-region endorheic basin in western USA. Bounding mountain ranges rise as much as 1,900 m above the nearly flat 379-km2 playa floor. Up to 3.8 m of Pleistocene Lake Bonneville mud and thin oolitic sand layers form the surface layer of the basin floor. Groundwater conditions were evaluated using data from shallow monitoring wells and borings, springs, infiltrometer measurements

The favorable overall conditions for the utilization of groundwater in fluvioglacial aquifers are impacted by significant heterogeneity in the hydraulic conductivity, which is related to small-scale facies changes. Knowledge of the spatial distribution of hydraulically relevant hydrofacies types (HF-types), derived by sedimentological analysis, helps to determine the hydraulic conductivity distribution

The groundwater flow patterns and temperature distribution of deep parent fluid in an area of Western Guangdong (China) have been reconstructed using chemical geothermometry and multicomponent mineral equilibrium (MME) based on water chemistry and stable isotopes. Thermal groundwater samples (three drill holes, nine springs) and groundwater samples of ‘normal’ temperature (one spring, eight wells)

Groundwater flow in an aquifer has frequently been found to be non-Darcian. In this study, a transient model of a variable-rate pumping test in a confined aquifer was established considering non-Darcian flow in the aquifer. A piecewise-linear function was adopted to reproduce the variability in pumping rate, and the classical Izbash equation was employed to describe the non-Darcian flow. The type-curve

Many regions of the earth are experiencing land subsidence owing to aquifer-system compaction, a consequence of groundwater depletion manifesting as excessive groundwater drawdown. The relation between groundwater drawdown and land subsidence caused by aquifer-system compaction is nonstationary in space and time due to the highly heterogeneous aquifer material, hydraulic and mechanical properties,

Groundwater recharge is critical to water circulation in arid and semi-arid regions. The accurate determination of groundwater recharge is required for assessing water resources and effectively managing groundwater, especially in water-limited areas. Based on field experiments and numerical models in a semi-arid region, this study assessed the effect of non-isothermal flow on groundwater recharge.

The hydraulic characterization of a highly anthropized coastal aquifer in France is presented. The current industrial operations of the study site prevent the use of standard ‘active’ hydrogeological investigation methods (pumping, slug tests). However, the studied field is bordered on its north-western side by a channel directly connected to the sea, which allows for characterization of the hydraulic

The original version of this article unfortunately contained mistakes.

Seawater intrusion (SWI) has triggered an accelerating process of freshwater contamination and significantly affected the soil fertility and local groundwater supply in the coastal area of Jiaozhou Bay, Shandong Province, China. This study establishes a three-dimensional numerical model based on SEAWAT code to simulate transient regional SWI to coastal aquifers in Dagu River Basin (DRB) adjacent to

Specific yield is a key parameter for the sustainable management of unconfined aquifers, since it relates water-table fluctuations to aquifer storage-changes and thus impacts water supply. However, estimating specific yield is still a challenge due to theoretical and methodological limitations. Water-storage changes in the aquifer and in the overlying unsaturated soil profile cause local changes in

Porosity is one of the most basic physical properties of a stratum. Previous studies have shown that porosity generally decreases with depth. There are five main types of empirical models available for describing such a porosity–depth relationship: the linear model, the exponential model, the power law model, the reciprocal model, and the parabolic model. For the majority of past and existing studies