Articles | Volume 22, issue 9
https://doi.org/10.5194/hess-22-4843-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/hess-22-4843-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Sep 2018
Research article |
| 18 Sep 2018
| 18 Sep 2018
Estimation of effective porosity in large-scale groundwater models by combining particle tracking, auto-calibration and 14C dating
Department of Geosciences and Natural Resources Management,
University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark
Peter Engesgaard
Department of Geosciences and Natural Resources Management,
University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark
Klaus Hinsby
Geological Survey of Denmark and Greenland, Øster Voldgade 10,
1350 Copenhagen, Denmark
Jan A. Piotrowski
Department of Geosciences, Aarhus
University, Høegh-Guldbergs Gade 2, 8000 Aarhus, Denmark
Torben O. Sonnenborg
Geological Survey of Denmark and Greenland, Øster Voldgade 10,
1350 Copenhagen, Denmark
Related authors
Janek Greskowiak, Rena Meyer, Jairo Cueto, Nico Skibbe, Anja Reckhardt, Thomas Günther, Stephan Ludger Seibert, Kai Schwalfenberg, Dietmar Pommerin, Mike Müller-Petke, and Gudrun Massmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-3132, https://doi.org/10.5194/egusphere-2025-3132, 2025
This preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS).
Short summary
Short summary
Mixing of fresh groundwater and circulating seawater below beaches triggers water-rock chemical reactions and may affect coastal water quality. The subsurface of so-called high-energy beaches that are exposed to high tides, waves and storm floods are understudied as monitoring under these conditions is difficult. For the first time, this study quantifies the subsurface flow and mixing processes of a high-energy beach with the help of computer simulations based on an extensive set of field data.
Rena Meyer, Janek Greskowiak, Stephan L. Seibert, Vincent E. Post, and Gudrun Massmann
Hydrol. Earth Syst. Sci., 29, 1469–1482, https://doi.org/10.5194/hess-29-1469-2025, https://doi.org/10.5194/hess-29-1469-2025, 2025
Short summary
Short summary
The subsurface of sandy beaches under high-energy conditions where tides, waves, and storms constantly reshape the beach surface is globally common and relevant for the alteration of solute fluxes across the land–sea continuum. Our generic modelling study highlights the relevance of dynamic boundary conditions paired with aquifer properties for groundwater flow, salt transport, and mixing reactions in coastal aquifers that are exposed to strong natural forces.
Rena Meyer, Wenmin Zhang, Søren Julsgaard Kragh, Mie Andreasen, Karsten Høgh Jensen, Rasmus Fensholt, Simon Stisen, and Majken C. Looms
Hydrol. Earth Syst. Sci., 26, 3337–3357, https://doi.org/10.5194/hess-26-3337-2022, https://doi.org/10.5194/hess-26-3337-2022, 2022
Short summary
Short summary
The amount and spatio-temporal distribution of soil moisture, the water in the upper soil, is of great relevance for agriculture and water management. Here, we investigate whether the established downscaling algorithm combining different satellite products to estimate medium-scale soil moisture is applicable to higher resolutions and whether results can be improved by accounting for land cover types. Original satellite data and downscaled soil moisture are compared with ground observations.
Djamil Al-Halbouni, Robert A. Watson, Eoghan P. Holohan, Rena Meyer, Ulrich Polom, Fernando M. Dos Santos, Xavier Comas, Hussam Alrshdan, Charlotte M. Krawczyk, and Torsten Dahm
Hydrol. Earth Syst. Sci., 25, 3351–3395, https://doi.org/10.5194/hess-25-3351-2021, https://doi.org/10.5194/hess-25-3351-2021, 2021
Short summary
Short summary
The rapid decline of the Dead Sea level since the 1960s has provoked a dynamic reaction from the coastal groundwater system, with physical and chemical erosion creating subsurface voids and conduits. By combining remote sensing, geophysical methods, and numerical modelling at the Dead Sea’s eastern shore, we link groundwater flow patterns to the formation of surface stream channels, sinkholes and uvalas. Better understanding of this karst system will improve regional hazard assessment.
Janek Greskowiak, Rena Meyer, Jairo Cueto, Nico Skibbe, Anja Reckhardt, Thomas Günther, Stephan Ludger Seibert, Kai Schwalfenberg, Dietmar Pommerin, Mike Müller-Petke, and Gudrun Massmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-3132, https://doi.org/10.5194/egusphere-2025-3132, 2025
This preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS).
Short summary
Short summary
Mixing of fresh groundwater and circulating seawater below beaches triggers water-rock chemical reactions and may affect coastal water quality. The subsurface of so-called high-energy beaches that are exposed to high tides, waves and storm floods are understudied as monitoring under these conditions is difficult. For the first time, this study quantifies the subsurface flow and mixing processes of a high-energy beach with the help of computer simulations based on an extensive set of field data.
Rena Meyer, Janek Greskowiak, Stephan L. Seibert, Vincent E. Post, and Gudrun Massmann
Hydrol. Earth Syst. Sci., 29, 1469–1482, https://doi.org/10.5194/hess-29-1469-2025, https://doi.org/10.5194/hess-29-1469-2025, 2025
Short summary
Short summary
The subsurface of sandy beaches under high-energy conditions where tides, waves, and storms constantly reshape the beach surface is globally common and relevant for the alteration of solute fluxes across the land–sea continuum. Our generic modelling study highlights the relevance of dynamic boundary conditions paired with aquifer properties for groundwater flow, salt transport, and mixing reactions in coastal aquifers that are exposed to strong natural forces.
Léonard Santos, Vazken Andréassian, Torben O. Sonnenborg, Göran Lindström, Alban de Lavenne, Charles Perrin, Lila Collet, and Guillaume Thirel
Hydrol. Earth Syst. Sci., 29, 683–700, https://doi.org/10.5194/hess-29-683-2025, https://doi.org/10.5194/hess-29-683-2025, 2025
Short summary
Short summary
This work investigates how hydrological models are transferred to a period in which climate conditions are different to the ones of the period in which they were set up. The robustness assessment test built to detect dependencies between model error and climatic drivers was applied to three hydrological models in 352 catchments in Denmark, France and Sweden. Potential issues are seen in a significant number of catchments for the models, even though the catchments differ for each model.
Trine Enemark, Rasmus Bødker Madsen, Torben O. Sonnenborg, Lærke Therese Andersen, Peter B. E. Sandersen, Jacob Kidmose, Ingelise Møller, Thomas Mejer Hansen, Karsten Høgh Jensen, and Anne-Sophie Høyer
Hydrol. Earth Syst. Sci., 28, 505–523, https://doi.org/10.5194/hess-28-505-2024, https://doi.org/10.5194/hess-28-505-2024, 2024
Short summary
Short summary
In this study, we demonstrate an approach to evaluate the interpretation uncertainty within a manually interpreted geological model in a groundwater model. Using qualitative estimates of uncertainties, several geological realizations are developed and implemented in groundwater models. We confirm existing evidence that if the conceptual model is well defined, interpretation uncertainties within the conceptual model have limited impact on groundwater model predictions.
Tanja Denager, Torben O. Sonnenborg, Majken C. Looms, Heye Bogena, and Karsten H. Jensen
Hydrol. Earth Syst. Sci., 27, 2827–2845, https://doi.org/10.5194/hess-27-2827-2023, https://doi.org/10.5194/hess-27-2827-2023, 2023
Short summary
Short summary
This study contributes to improvements in the model characterization of water and energy fluxes. The results show that multi-objective autocalibration in combination with mathematical regularization is a powerful tool to improve land surface models. Using the direct measurement of turbulent fluxes as the target variable, parameter optimization matches simulations and observations of latent heat, whereas sensible heat is clearly biased.
Ane LaBianca, Mette H. Mortensen, Peter Sandersen, Torben O. Sonnenborg, Karsten H. Jensen, and Jacob Kidmose
Hydrol. Earth Syst. Sci., 27, 1645–1666, https://doi.org/10.5194/hess-27-1645-2023, https://doi.org/10.5194/hess-27-1645-2023, 2023
Short summary
Short summary
The study explores the effect of Anthropocene geology and the computational grid size on the simulation of shallow urban groundwater. Many cities are facing challenges with high groundwater levels close to the surface, yet urban planning and development seldom consider its impact on the groundwater resource. This study illustrates that the urban subsurface infrastructure significantly affects the groundwater flow paths and the residence time of shallow urban groundwater.
Rena Meyer, Wenmin Zhang, Søren Julsgaard Kragh, Mie Andreasen, Karsten Høgh Jensen, Rasmus Fensholt, Simon Stisen, and Majken C. Looms
Hydrol. Earth Syst. Sci., 26, 3337–3357, https://doi.org/10.5194/hess-26-3337-2022, https://doi.org/10.5194/hess-26-3337-2022, 2022
Short summary
Short summary
The amount and spatio-temporal distribution of soil moisture, the water in the upper soil, is of great relevance for agriculture and water management. Here, we investigate whether the established downscaling algorithm combining different satellite products to estimate medium-scale soil moisture is applicable to higher resolutions and whether results can be improved by accounting for land cover types. Original satellite data and downscaled soil moisture are compared with ground observations.
Ida Karlsson Seidenfaden, Torben Obel Sonnenborg, Jens Christian Refsgaard, Christen Duus Børgesen, Jørgen Eivind Olesen, and Dennis Trolle
Hydrol. Earth Syst. Sci., 26, 955–973, https://doi.org/10.5194/hess-26-955-2022, https://doi.org/10.5194/hess-26-955-2022, 2022
Short summary
Short summary
This study investigates how the spatial nitrate reduction in the subsurface may shift under changing climate and land use conditions. This change is investigated by comparing maps showing the spatial nitrate reduction in an agricultural catchment for current conditions, with maps generated for future projected climate and land use conditions. Results show that future climate flow paths may shift the catchment reduction noticeably, while implications of land use changes were less substantial.
Djamil Al-Halbouni, Robert A. Watson, Eoghan P. Holohan, Rena Meyer, Ulrich Polom, Fernando M. Dos Santos, Xavier Comas, Hussam Alrshdan, Charlotte M. Krawczyk, and Torsten Dahm
Hydrol. Earth Syst. Sci., 25, 3351–3395, https://doi.org/10.5194/hess-25-3351-2021, https://doi.org/10.5194/hess-25-3351-2021, 2021
Short summary
Short summary
The rapid decline of the Dead Sea level since the 1960s has provoked a dynamic reaction from the coastal groundwater system, with physical and chemical erosion creating subsurface voids and conduits. By combining remote sensing, geophysical methods, and numerical modelling at the Dead Sea’s eastern shore, we link groundwater flow patterns to the formation of surface stream channels, sinkholes and uvalas. Better understanding of this karst system will improve regional hazard assessment.
Julian Koch, Helen Berger, Hans Jørgen Henriksen, and Torben Obel Sonnenborg
Hydrol. Earth Syst. Sci., 23, 4603–4619, https://doi.org/10.5194/hess-23-4603-2019, https://doi.org/10.5194/hess-23-4603-2019, 2019
Short summary
Short summary
This study explores novel modelling avenues using machine learning in combination with process-based models to predict the shallow water table at high spatial resolution. Due to climate change and anthropogenic impacts, the shallow groundwater is rising in many parts of the world. In order to adapt to risks induced by groundwater flooding, new modelling tools need to emerge. In this study, we found that machine learning is capable of reaching the required accuracy and resolution.
T. O. Sonnenborg, D. Seifert, and J. C. Refsgaard
Hydrol. Earth Syst. Sci., 19, 3891–3901, https://doi.org/10.5194/hess-19-3891-2015, https://doi.org/10.5194/hess-19-3891-2015, 2015
Short summary
Short summary
The impacts of climate model uncertainty and geological model uncertainty on hydraulic head, stream flow, travel time and capture zones are evaluated. Six versions of a physically based and distributed hydrological model, each containing a unique interpretation of the geological structure of the model area, are forced by 11 climate model projections. Geology is the dominating uncertainty source for travel time and capture zones, while climate dominates for hydraulic heads and steam flow.
J. R. Poulsen, E. Sebok, C. Duque, D. Tetzlaff, and P. K. Engesgaard
Hydrol. Earth Syst. Sci., 19, 1871–1886, https://doi.org/10.5194/hess-19-1871-2015, https://doi.org/10.5194/hess-19-1871-2015, 2015
X. L. He, T. O. Sonnenborg, F. Jørgensen, and K. H. Jensen
Hydrol. Earth Syst. Sci., 18, 2943–2954, https://doi.org/10.5194/hess-18-2943-2014, https://doi.org/10.5194/hess-18-2943-2014, 2014
I. B. Karlsson, T. O. Sonnenborg, K. H. Jensen, and J. C. Refsgaard
Hydrol. Earth Syst. Sci., 18, 595–610, https://doi.org/10.5194/hess-18-595-2014, https://doi.org/10.5194/hess-18-595-2014, 2014
X. He, T. O. Sonnenborg, F. Jørgensen, A.-S. Høyer, R. R. Møller, and K. H. Jensen
Hydrol. Earth Syst. Sci., 17, 3245–3260, https://doi.org/10.5194/hess-17-3245-2013, https://doi.org/10.5194/hess-17-3245-2013, 2013
P. Rasmussen, T. O. Sonnenborg, G. Goncear, and K. Hinsby
Hydrol. Earth Syst. Sci., 17, 421–443, https://doi.org/10.5194/hess-17-421-2013, https://doi.org/10.5194/hess-17-421-2013, 2013
Related subject area
Subject: Groundwater hydrology | Techniques and Approaches: Modelling approaches
Towards a global spatial machine learning model for seasonal groundwater level predictions in Germany
The impact of geological structures on groundwater potential assessment in volcanic rocks in the Borena Sayint district, northwestern Ethiopian Plateau: a review
Numerical analysis of the effect of heterogeneity on CO2 dissolution enhanced by gravity-driven convection
Multivariate and long-term time series analysis to assess the effect of nitrogen management policy on groundwater quality in Wallonia, BE
Laboratory heat transport experiments reveal grain-size- and flow-velocity-dependent local thermal non-equilibrium effects
Improvement of the KarstMod modelling platform for a better assessment of karst groundwater resources
Topothermohaline convection – from synthetic simulations to reveal processes in a thick geothermal system
Training deep learning models with a multi-station approach and static aquifer attributes for groundwater level simulation: what is the best way to leverage regionalised information?
Improving heat transfer predictions in heterogeneous riparian zones using transfer learning techniques
Data-driven modelling of hydraulic-head time series: results and lessons learned from the 2022 Groundwater Time Series Modelling Challenge
The impact of future changes in climate variables and groundwater abstraction on basin-scale groundwater availability
Assessing groundwater level modelling using a 1-D convolutional neural network (CNN): linking model performances to geospatial and time series features
Reinforce lake water balance components estimations by integrating water isotope compositions with a hydrological model
Short high-accuracy tritium data time series for assessing groundwater mean transit times in the vadose and saturated zones of the Luxembourg Sandstone aquifer
High-resolution long-term average groundwater recharge in Africa estimated using random forest regression and residual interpolation
Towards understanding the influence of seasons on low-groundwater periods based on explainable machine learning
Shannon entropy of transport self-organization due to dissolution–precipitation reaction at varying Peclet numbers in initially homogeneous porous media
A high-resolution map of diffuse groundwater recharge rates for Australia
Influence of bank slope on sinuosity-driven hyporheic exchange flow and residence time distribution during a dynamic flood event
Technical note: A model of chemical transport in a wellbore–aquifer system
Disentangling coastal groundwater level dynamics in a global dataset
Current and future roles of meltwater–groundwater dynamics in a proglacial Alpine outwash plain
On the challenges of global entity-aware deep learning models for groundwater level prediction
Incorporating interpretation uncertainties from deterministic 3D hydrostratigraphic models in groundwater models
Adjoint subordination to calculate backward travel time probability of pollutants in water with various velocity resolutions
On the optimal level of complexity for the representation of groundwater-dependent wetland systems in land surface models
Estimation of groundwater age distributions from hydrochemistry: comparison of two metamodelling algorithms in the Heretaunga Plains aquifer system, New Zealand
Technical note: Novel analytical solution for groundwater response to atmospheric tides
Calibration of groundwater seepage against the spatial distribution of the stream network to assess catchment-scale hydraulic properties
Climate-warming-driven changes in the cryosphere and their impact on groundwater–surface-water interactions in the Heihe River basin
Comparison of artificial neural networks and reservoir models for simulating karst spring discharge on five test sites in the Alpine and Mediterranean regions
A general model of radial dispersion with wellbore mixing and skin effects
Estimation of hydraulic conductivity functions in karst regions by particle swarm optimization with application to Lake Vrana, Croatia
The origin of hydrological responses following earthquakes in a confined aquifer: insight from water level, flow rate, and temperature observations
Advance prediction of coastal groundwater levels with temporal convolutional and long short-term memory networks
Three-dimensional hydrogeological parametrization using sparse piezometric data
Machine-learning-based downscaling of modelled climate change impacts on groundwater table depth
Frequency domain water table fluctuations reveal impacts of intense rainfall and vadose zone thickness on groundwater recharge
Characterizing groundwater heat transport in a complex lowland aquifer using paleo-temperature reconstruction, satellite data, temperature–depth profiles, and numerical models
Karst spring recession and classification: efficient, automated methods for both fast- and slow-flow components
Exploring river–aquifer interactions and hydrological system response using baseflow separation, impulse response modeling, and time series analysis in three temperate lowland catchments
Experimental study of non-Darcy flow characteristics in permeable stones
Karst spring discharge modeling based on deep learning using spatially distributed input data
HESS Opinions: Chemical transport modeling in subsurface hydrological systems – space, time, and the “holy grail” of “upscaling”
Spatiotemporal variations in water sources and mixing spots in a riparian zone
Delineation of discrete conduit networks in karst aquifers via combined analysis of tracer tests and geophysical data
Reactive transport modeling for supporting climate resilience at groundwater contamination sites
Improved understanding of regional groundwater drought development through time series modelling: the 2018–2019 drought in the Netherlands
Simulation of long-term spatiotemporal variations in regional-scale groundwater recharge: contributions of a water budget approach in cold and humid climates
Feedback mechanisms between precipitation and dissolution reactions across randomly heterogeneous conductivity fields
Stefan Kunz, Alexander Schulz, Maria Wetzel, Maximilian Nölscher, Teodor Chiaburu, Felix Biessmann, and Stefan Broda
Hydrol. Earth Syst. Sci., 29, 3405–3433, https://doi.org/10.5194/hess-29-3405-2025, https://doi.org/10.5194/hess-29-3405-2025, 2025
Short summary
Short summary
Accurate groundwater level predictions are crucial for sustainable management. This study applies two machine learning models – Neural Hierarchical Interpolation for Time Series Forecasting (N-HiTS) and the Temporal Fusion Transformer (TFT) – to forecast seasonal groundwater levels for 5288 wells across Germany. N-HiTS outperformed TFT, with both models performing well in diverse hydrogeological settings, particularly in lowlands with distinct seasonal dynamics.
Bishaw Mihret and Ajebush Wuletaw
Hydrol. Earth Syst. Sci., 29, 2951–2959, https://doi.org/10.5194/hess-29-2951-2025, https://doi.org/10.5194/hess-29-2951-2025, 2025
Short summary
Short summary
This review highlights how geological structures like faults and fractures influence groundwater potential in volcanic rocks of Borena Sayint, northwestern Ethiopian Plateau. These structures enhance secondary porosity, affecting aquifer behaviour. The study stresses integrating geological, geophysical, and hydrological data for sustainable groundwater management in tectonically complex volcanic regions.
Yufei Wang, Daniel Fernàndez-Garcia, and Maarten W. Saaltink
Hydrol. Earth Syst. Sci., 29, 2485–2503, https://doi.org/10.5194/hess-29-2485-2025, https://doi.org/10.5194/hess-29-2485-2025, 2025
Short summary
Short summary
During geological carbon sequestration, the injected supercritical CO2, being less dense, floats above the brine. The dissolution of CO2 into brine helps mitigate the risk of CO2 leakage. As CO2 dissolves into the brine, it increases the density of brine in the upper layer, initiating gravity-driven convection (GDC), which significantly enhances the rate of CO2 dissolution. We derived two empirical formulas to predict the asymptotic dissolution rate driven by GDC in heterogeneous fields.
Elise Verstraeten, Alice Alonso, Louise Collier, and Marnik Vanclooster
Hydrol. Earth Syst. Sci., 29, 1829–1845, https://doi.org/10.5194/hess-29-1829-2025, https://doi.org/10.5194/hess-29-1829-2025, 2025
Short summary
Short summary
This study takes a data-driven approach to evaluate long-term groundwater nitrate concentration trends in Wallonia, Belgium, over ~20 years following the implementation of regional nitrogen management policies. Results highlight a persistently negative impact of agricultural land use, the importance of sustained policies and long-term monitoring to mitigate nitrogen legacy effects, and the need for improved datasets to better capture controlling factors.
Haegyeong Lee, Manuel Gossler, Kai Zosseder, Philipp Blum, Peter Bayer, and Gabriel C. Rau
Hydrol. Earth Syst. Sci., 29, 1359–1378, https://doi.org/10.5194/hess-29-1359-2025, https://doi.org/10.5194/hess-29-1359-2025, 2025
Short summary
Short summary
A systematic laboratory experiment elucidates two-phase heat transport due to water flow in saturated porous media to understand thermal propagation in aquifers. Results reveal delayed thermal arrival in the solid phase, depending on grain size and flow velocity. Analytical modeling using standard local thermal equilibrium (LTE) and advanced local thermal non-equilibrium (LTNE) theory fails to describe temperature breakthrough curves, highlighting the need for more advanced numerical approaches.
Vianney Sivelle, Guillaume Cinkus, Naomi Mazzilli, David Labat, Bruno Arfib, Nicolas Massei, Yohann Cousquer, Dominique Bertin, and Hervé Jourde
Hydrol. Earth Syst. Sci., 29, 1259–1276, https://doi.org/10.5194/hess-29-1259-2025, https://doi.org/10.5194/hess-29-1259-2025, 2025
Short summary
Short summary
KarstMod provides a platform for global modelling of the rain level–flow relationship in karstic basins. The platform provides a set of tools to assess the dynamics of the compartments considered in the model and to detect possible flaws in structure and parameterization. This platform is developed as part of the French observatory network on karst hydrology (SNO KARST), which aims to strengthen the sharing of knowledge and promote interdisciplinary research on karst systems at a national level.
Attila Galsa, Márk Szijártó, Ádám Tóth, and Judit Mádl-Szőnyi
EGUsphere, https://doi.org/10.5194/egusphere-2025-559, https://doi.org/10.5194/egusphere-2025-559, 2025
Short summary
Short summary
Understanding groundwater flow is crucial for both environmental and economic reasons. In our study, the dynamic interaction of the forces driving groundwater flow is presented, partly in synthetic models and partly in a real deep geothermal reservoir. We point out that ignoring certain driving forces can lead to oversimplification of groundwater flow and even misinterpretation of the phenomena, causing environmental problems or economic losses.
Sivarama Krishna Reddy Chidepudi, Nicolas Massei, Abderrahim Jardani, Bastien Dieppois, Abel Henriot, and Matthieu Fournier
Hydrol. Earth Syst. Sci., 29, 841–861, https://doi.org/10.5194/hess-29-841-2025, https://doi.org/10.5194/hess-29-841-2025, 2025
Short summary
Short summary
This study explores how deep learning can improve our understanding of groundwater levels, using an approach that combines climate data and physical characteristics of aquifers. By focusing on different types of groundwater levels and employing techniques like clustering and wavelet transform, the study highlights the importance of targeting relevant information. This research not only advances groundwater simulation but also emphasizes the benefits of different modelling approaches.
Aohan Jin, Wenguang Shi, Renjie Zhou, Hongbin Zhan, Quanrong Wang, and Xuan Gu
EGUsphere, https://doi.org/10.5194/egusphere-2024-4145, https://doi.org/10.5194/egusphere-2024-4145, 2025
Short summary
Short summary
This study developed a novel deep transfer learning (DTL) approach, which integrates the physical mechanisms from an analytical model using a transfer learning technique. Results indicate that the DTL model maintains satisfactory performance even in heterogeneous conditions, with uncertainties in observations and sparse training data compared to the DNN model.
Raoul A. Collenteur, Ezra Haaf, Mark Bakker, Tanja Liesch, Andreas Wunsch, Jenny Soonthornrangsan, Jeremy White, Nick Martin, Rui Hugman, Ed de Sousa, Didier Vanden Berghe, Xinyang Fan, Tim J. Peterson, Jānis Bikše, Antoine Di Ciacca, Xinyue Wang, Yang Zheng, Maximilian Nölscher, Julian Koch, Raphael Schneider, Nikolas Benavides Höglund, Sivarama Krishna Reddy Chidepudi, Abel Henriot, Nicolas Massei, Abderrahim Jardani, Max Gustav Rudolph, Amir Rouhani, J. Jaime Gómez-Hernández, Seifeddine Jomaa, Anna Pölz, Tim Franken, Morteza Behbooei, Jimmy Lin, and Rojin Meysami
Hydrol. Earth Syst. Sci., 28, 5193–5208, https://doi.org/10.5194/hess-28-5193-2024, https://doi.org/10.5194/hess-28-5193-2024, 2024
Short summary
Short summary
We show the results of the 2022 Groundwater Time Series Modelling Challenge; 15 teams applied data-driven models to simulate hydraulic heads, and three model groups were identified: lumped, machine learning, and deep learning. For all wells, reasonable performance was obtained by at least one team from each group. There was not one team that performed best for all wells. In conclusion, the challenge was a successful initiative to compare different models and learn from each other.
Steven Reinaldo Rusli, Victor F. Bense, Syed M. T. Mustafa, and Albrecht H. Weerts
Hydrol. Earth Syst. Sci., 28, 5107–5131, https://doi.org/10.5194/hess-28-5107-2024, https://doi.org/10.5194/hess-28-5107-2024, 2024
Short summary
Short summary
In this paper, we investigate the impact of climatic and anthropogenic factors on future groundwater availability. The changes are simulated using hydrological and groundwater flow models. We find that future groundwater status is influenced more by anthropogenic factors than climatic factors. The results are beneficial for informing responsible parties in operational water management about achieving future (ground)water governance.
Mariana Gomez, Maximilian Nölscher, Andreas Hartmann, and Stefan Broda
Hydrol. Earth Syst. Sci., 28, 4407–4425, https://doi.org/10.5194/hess-28-4407-2024, https://doi.org/10.5194/hess-28-4407-2024, 2024
Short summary
Short summary
To understand the impact of external factors on groundwater level modelling using a 1-D convolutional neural network (CNN) model, we train, validate, and tune individual CNN models for 505 wells distributed across Lower Saxony, Germany. We then evaluate the performance of these models against available geospatial and time series features. This study provides new insights into the relationship between these factors and the accuracy of groundwater modelling.
Nariman Mahmoodi, Ulrich Struck, Michael Schneider, and Christoph Merz
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2024-214, https://doi.org/10.5194/hess-2024-214, 2024
Revised manuscript accepted for HESS
Short summary
Short summary
Understanding water balance in lakes is complex. We studied Lake Gross Glienicke in Germany, using an innovative method that combines isotope measurements and a hydrological model to improve estimates of water inflow and evaporation. Our findings show a high correlation between the two approaches, leading to better predictions of lake water dynamics. This research offers a reliable way to evaluate the model outputs.
Laurent Gourdol, Michael K. Stewart, Uwe Morgenstern, and Laurent Pfister
Hydrol. Earth Syst. Sci., 28, 3519–3547, https://doi.org/10.5194/hess-28-3519-2024, https://doi.org/10.5194/hess-28-3519-2024, 2024
Short summary
Short summary
Determining water transit times in aquifers is key to a better understanding of groundwater resources and their sustainable management. For our research, we used high-accuracy tritium data from 35 springs draining the Luxembourg Sandstone aquifer. We assessed the mean transit times of groundwater and found that water moves on average more than 10 times more slowly vertically in the vadose zone of the aquifer (~12 m yr-1) than horizontally in its saturated zone (~170 m yr-1).
Anna Pazola, Mohammad Shamsudduha, Jon French, Alan M. MacDonald, Tamiru Abiye, Ibrahim Baba Goni, and Richard G. Taylor
Hydrol. Earth Syst. Sci., 28, 2949–2967, https://doi.org/10.5194/hess-28-2949-2024, https://doi.org/10.5194/hess-28-2949-2024, 2024
Short summary
Short summary
This study advances groundwater research using a high-resolution random forest model, revealing new recharge areas and spatial variability, mainly in humid regions. Limited data in rainy zones is a constraint for the model. Our findings underscore the promise of machine learning for large-scale groundwater modelling while further emphasizing the importance of data collection for robust results.
Andreas Wunsch, Tanja Liesch, and Nico Goldscheider
Hydrol. Earth Syst. Sci., 28, 2167–2178, https://doi.org/10.5194/hess-28-2167-2024, https://doi.org/10.5194/hess-28-2167-2024, 2024
Short summary
Short summary
Seasons have a strong influence on groundwater levels, but relationships are complex and partly unknown. Using data from wells in Germany and an explainable machine learning approach, we showed that summer precipitation is the key factor that controls the severeness of a low-water period in fall; high summer temperatures do not per se cause stronger decreases. Preceding winters have only a minor influence on such low-water periods in general.
Evgeny Shavelzon and Yaniv Edery
Hydrol. Earth Syst. Sci., 28, 1803–1826, https://doi.org/10.5194/hess-28-1803-2024, https://doi.org/10.5194/hess-28-1803-2024, 2024
Short summary
Short summary
We investigate the interaction of transport with dissolution–precipitation reactions in porous media using the concepts of entropy and work to quantify the emergence of preferential flow paths. We show that the preferential-flow-path phenomenon and the hydraulic power required to maintain the driving pressure drop intensify over time along with the heterogeneity due to the interaction between the transport and the reactive processes. This is more pronounced in diffusion-dominated flows.
Stephen Lee, Dylan J. Irvine, Clément Duvert, Gabriel C. Rau, and Ian Cartwright
Hydrol. Earth Syst. Sci., 28, 1771–1790, https://doi.org/10.5194/hess-28-1771-2024, https://doi.org/10.5194/hess-28-1771-2024, 2024
Short summary
Short summary
Global groundwater recharge studies collate recharge values estimated using different methods that apply to different timescales. We develop a recharge prediction model, based solely on chloride, to produce a recharge map for Australia. We reveal that climate and vegetation have the most significant influence on recharge variability in Australia. Our recharge rates were lower than other models due to the long timescale of chloride in groundwater. Our method can similarly be applied globally.
Yiming Li, Uwe Schneidewind, Zhang Wen, Stefan Krause, and Hui Liu
Hydrol. Earth Syst. Sci., 28, 1751–1769, https://doi.org/10.5194/hess-28-1751-2024, https://doi.org/10.5194/hess-28-1751-2024, 2024
Short summary
Short summary
Meandering rivers are an integral part of many landscapes around the world. Here we used a new modeling approach to look at how the slope of riverbanks influences water flow and solute transport from a meandering river channel through its bank and into/out of the connected groundwater compartment (aquifer). We found that the bank slope can be a significant factor to be considered, especially when bank slope angles are small, and riverbank and aquifer conditions only allow for slow water flow.
Yiqun Gan and Quanrong Wang
Hydrol. Earth Syst. Sci., 28, 1317–1323, https://doi.org/10.5194/hess-28-1317-2024, https://doi.org/10.5194/hess-28-1317-2024, 2024
Short summary
Short summary
1. A revised 3D model of solute transport is developed in the well–aquifer system. 2. The accuracy of the new model is tested against benchmark analytical solutions. 3. Previous models overestimate the concentration of solute in both aquifers and wellbores in the injection well test case. 4. Previous models underestimate the concentration in the extraction well test case.
Annika Nolte, Ezra Haaf, Benedikt Heudorfer, Steffen Bender, and Jens Hartmann
Hydrol. Earth Syst. Sci., 28, 1215–1249, https://doi.org/10.5194/hess-28-1215-2024, https://doi.org/10.5194/hess-28-1215-2024, 2024
Short summary
Short summary
This study examines about 8000 groundwater level (GWL) time series from five continents to explore similarities in groundwater systems at different scales. Statistical metrics and machine learning techniques are applied to identify common GWL dynamics patterns and analyze their controlling factors. The study also highlights the potential and limitations of this data-driven approach to improve our understanding of groundwater recharge and discharge processes.
Tom Müller, Matteo Roncoroni, Davide Mancini, Stuart N. Lane, and Bettina Schaefli
Hydrol. Earth Syst. Sci., 28, 735–759, https://doi.org/10.5194/hess-28-735-2024, https://doi.org/10.5194/hess-28-735-2024, 2024
Short summary
Short summary
We investigate the role of a newly formed floodplain in an alpine glaciated catchment to store and release water. Based on field measurements, we built a numerical model to simulate the water fluxes and show that recharge occurs mainly due to the ice-melt-fed river. We identify three future floodplains, which could emerge from glacier retreat, and show that their combined storage leads to some additional groundwater storage but contributes little additional baseflow for the downstream river.
Benedikt Heudorfer, Tanja Liesch, and Stefan Broda
Hydrol. Earth Syst. Sci., 28, 525–543, https://doi.org/10.5194/hess-28-525-2024, https://doi.org/10.5194/hess-28-525-2024, 2024
Short summary
Short summary
We build a neural network to predict groundwater levels from monitoring wells. We predict all wells at the same time, by learning the differences between wells with static features, making it an entity-aware global model. This works, but we also test different static features and find that the model does not use them to learn exactly how the wells are different, but only to uniquely identify them. As this model class is not actually entity aware, we suggest further steps to make it so.
Trine Enemark, Rasmus Bødker Madsen, Torben O. Sonnenborg, Lærke Therese Andersen, Peter B. E. Sandersen, Jacob Kidmose, Ingelise Møller, Thomas Mejer Hansen, Karsten Høgh Jensen, and Anne-Sophie Høyer
Hydrol. Earth Syst. Sci., 28, 505–523, https://doi.org/10.5194/hess-28-505-2024, https://doi.org/10.5194/hess-28-505-2024, 2024
Short summary
Short summary
In this study, we demonstrate an approach to evaluate the interpretation uncertainty within a manually interpreted geological model in a groundwater model. Using qualitative estimates of uncertainties, several geological realizations are developed and implemented in groundwater models. We confirm existing evidence that if the conceptual model is well defined, interpretation uncertainties within the conceptual model have limited impact on groundwater model predictions.
Yong Zhang, Graham E. Fogg, HongGuang Sun, Donald M. Reeves, Roseanna M. Neupauer, and Wei Wei
Hydrol. Earth Syst. Sci., 28, 179–203, https://doi.org/10.5194/hess-28-179-2024, https://doi.org/10.5194/hess-28-179-2024, 2024
Short summary
Short summary
Pollutant release history and source identification are helpful for managing water resources, but it remains a challenge to reliably identify such information for real-world, complex transport processes in rivers and aquifers. In this study, we filled this knowledge gap by deriving a general backward governing equation and developing the efficient solver. Field applications showed that this model and solver are applicable for a broad range of flow systems, dimensions, and spatiotemporal scales.
Mennatullah T. Elrashidy, Andrew M. Ireson, and Saman Razavi
Hydrol. Earth Syst. Sci., 27, 4595–4608, https://doi.org/10.5194/hess-27-4595-2023, https://doi.org/10.5194/hess-27-4595-2023, 2023
Short summary
Short summary
Wetlands are important ecosystems that store carbon and play a vital role in the water cycle. However, hydrological computer models do not always represent wetlands and their interaction with groundwater accurately. We tested different possible ways to include groundwater–wetland interactions in these models. We found that the optimal method to include wetlands and groundwater in the models is reliant on the intended use of the models and the characteristics of the land and soil being studied.
Conny Tschritter, Christopher J. Daughney, Sapthala Karalliyadda, Brioch Hemmings, Uwe Morgenstern, and Catherine Moore
Hydrol. Earth Syst. Sci., 27, 4295–4316, https://doi.org/10.5194/hess-27-4295-2023, https://doi.org/10.5194/hess-27-4295-2023, 2023
Short summary
Short summary
Understanding groundwater travel time (groundwater age) is crucial for tracking flow and contaminants. While groundwater age is usually inferred from age tracers, this study utilised two machine learning techniques with common groundwater chemistry data. The results of both methods correspond to traditional approaches. They are useful where hydrochemistry data exist but age tracer data are limited. These methods could help enhance our knowledge, aiding in sustainable freshwater management.
Jose M. Bastias Espejo, Chris Turnadge, Russell S. Crosbie, Philipp Blum, and Gabriel C. Rau
Hydrol. Earth Syst. Sci., 27, 3447–3462, https://doi.org/10.5194/hess-27-3447-2023, https://doi.org/10.5194/hess-27-3447-2023, 2023
Short summary
Short summary
Analytical models estimate subsurface properties from subsurface–tidal load interactions. However, they have limited accuracy in representing subsurface physics and parameter estimation. We derived a new analytical solution which models flow to wells due to atmospheric tides. We applied it to field data and compared our findings with subsurface knowledge. Our results enhance understanding of subsurface systems, providing valuable information on their behavior.
Ronan Abhervé, Clément Roques, Alexandre Gauvain, Laurent Longuevergne, Stéphane Louaisil, Luc Aquilina, and Jean-Raynald de Dreuzy
Hydrol. Earth Syst. Sci., 27, 3221–3239, https://doi.org/10.5194/hess-27-3221-2023, https://doi.org/10.5194/hess-27-3221-2023, 2023
Short summary
Short summary
We propose a model calibration method constraining groundwater seepage in the hydrographic network. The method assesses the hydraulic properties of aquifers in regions where perennial streams are directly fed by groundwater. The estimated hydraulic conductivity appear to be highly sensitive to the spatial extent and density of streams. Such an approach improving subsurface characterization from surface information is particularly interesting for ungauged basins.
Amanda Triplett and Laura E. Condon
Hydrol. Earth Syst. Sci., 27, 2763–2785, https://doi.org/10.5194/hess-27-2763-2023, https://doi.org/10.5194/hess-27-2763-2023, 2023
Short summary
Short summary
Accelerated melting in mountains is a global phenomenon. The Heihe River basin depends on upstream mountains for its water supply. We built a hydrologic model to examine how shifts in streamflow and warming will impact ground and surface water interactions. The results indicate that degrading permafrost has a larger effect than melting glaciers. Additionally, warming temperatures tend to have more impact than changes to streamflow. These results can inform other mountain–valley system studies.
Guillaume Cinkus, Andreas Wunsch, Naomi Mazzilli, Tanja Liesch, Zhao Chen, Nataša Ravbar, Joanna Doummar, Jaime Fernández-Ortega, Juan Antonio Barberá, Bartolomé Andreo, Nico Goldscheider, and Hervé Jourde
Hydrol. Earth Syst. Sci., 27, 1961–1985, https://doi.org/10.5194/hess-27-1961-2023, https://doi.org/10.5194/hess-27-1961-2023, 2023
Short summary
Short summary
Numerous modelling approaches can be used for studying karst water resources, which can make it difficult for a stakeholder or researcher to choose the appropriate method. We conduct a comparison of two widely used karst modelling approaches: artificial neural networks (ANNs) and reservoir models. Results show that ANN models are very flexible and seem great for reproducing high flows. Reservoir models can work with relatively short time series and seem to accurately reproduce low flows.
Wenguang Shi, Quanrong Wang, Hongbin Zhan, Renjie Zhou, and Haitao Yan
Hydrol. Earth Syst. Sci., 27, 1891–1908, https://doi.org/10.5194/hess-27-1891-2023, https://doi.org/10.5194/hess-27-1891-2023, 2023
Short summary
Short summary
The mechanism of radial dispersion is important for understanding reactive transport in the subsurface and for estimating aquifer parameters required in the optimization design of remediation strategies. A general model and associated analytical solutions are developed in this study. The new model represents the most recent advancement on radial dispersion studies and incorporates a host of important processes that are not taken into consideration in previous investigations.
Vanja Travaš, Luka Zaharija, Davor Stipanić, and Siniša Družeta
Hydrol. Earth Syst. Sci., 27, 1343–1359, https://doi.org/10.5194/hess-27-1343-2023, https://doi.org/10.5194/hess-27-1343-2023, 2023
Short summary
Short summary
In order to model groundwater flow in karst aquifers, it is necessary to approximate the influence of the unknown and irregular structure of the karst conduits. For this purpose, a procedure based on inverse modeling is adopted. Moreover, in order to reconstruct the functional dependencies related to groundwater flow, the particle swarm method was used, through which the optimal solution of unknown functions is found by imitating the movement of ants in search of food.
Shouchuan Zhang, Zheming Shi, Guangcai Wang, Zuochen Zhang, and Huaming Guo
Hydrol. Earth Syst. Sci., 27, 401–415, https://doi.org/10.5194/hess-27-401-2023, https://doi.org/10.5194/hess-27-401-2023, 2023
Short summary
Short summary
We documented the step-like increases of water level, flow rate, and water temperatures in a confined aquifer following multiple earthquakes. By employing tidal analysis and a coupled temperature and flow rate model, we find that post-seismic vertical permeability changes and recharge model could explain the co-seismic response. And co-seismic temperature changes are caused by mixing of different volumes of water, with the mixing ratio varying according to each earthquake.
Xiaoying Zhang, Fan Dong, Guangquan Chen, and Zhenxue Dai
Hydrol. Earth Syst. Sci., 27, 83–96, https://doi.org/10.5194/hess-27-83-2023, https://doi.org/10.5194/hess-27-83-2023, 2023
Short summary
Short summary
In a data-driven framework, groundwater levels can generally only be calculated 1 time step ahead. We discuss the advance prediction with longer forecast periods rather than single time steps by constructing a model based on a temporal convolutional network. Model accuracy and efficiency were further compared with an LSTM-based model. The two models derived in this study can help people cope with the uncertainty of what might occur in hydrological scenarios under the threat of climate change.
Dimitri Rambourg, Raphaël Di Chiara, and Philippe Ackerer
Hydrol. Earth Syst. Sci., 26, 6147–6162, https://doi.org/10.5194/hess-26-6147-2022, https://doi.org/10.5194/hess-26-6147-2022, 2022
Short summary
Short summary
The reproduction of flows and contaminations underground requires a good estimation of the parameters of the geological environment (mainly permeability and porosity), in three dimensions. While most researchers rely on geophysical methods, which are costly and difficult to implement in the field, this study proposes an alternative using data that are already widely available: piezometric records (monitoring of the water table) and the lithological description of the piezometric wells.
Raphael Schneider, Julian Koch, Lars Troldborg, Hans Jørgen Henriksen, and Simon Stisen
Hydrol. Earth Syst. Sci., 26, 5859–5877, https://doi.org/10.5194/hess-26-5859-2022, https://doi.org/10.5194/hess-26-5859-2022, 2022
Short summary
Short summary
Hydrological models at high spatial resolution are computationally expensive. However, outputs from such models, such as the depth of the groundwater table, are often desired in high resolution. We developed a downscaling algorithm based on machine learning that allows us to increase spatial resolution of hydrological model outputs, alleviating computational burden. We successfully applied the downscaling algorithm to the climate-change-induced impacts on the groundwater table across Denmark.
Luca Guillaumot, Laurent Longuevergne, Jean Marçais, Nicolas Lavenant, and Olivier Bour
Hydrol. Earth Syst. Sci., 26, 5697–5720, https://doi.org/10.5194/hess-26-5697-2022, https://doi.org/10.5194/hess-26-5697-2022, 2022
Short summary
Short summary
Recharge, defining the renewal rate of groundwater resources, is difficult to estimate at basin scale. Here, recharge variations are inferred from water table variations recorded in boreholes. First, results show that aquifer-scale properties controlling these variations can be inferred from boreholes. Second, groundwater is recharged by both intense and seasonal rainfall. Third, the short-term contribution appears overestimated in recharge models and depends on the unsaturated zone thickness.
Alberto Casillas-Trasvina, Bart Rogiers, Koen Beerten, Laurent Wouters, and Kristine Walraevens
Hydrol. Earth Syst. Sci., 26, 5577–5604, https://doi.org/10.5194/hess-26-5577-2022, https://doi.org/10.5194/hess-26-5577-2022, 2022
Short summary
Short summary
Heat in the subsurface can be used to characterize aquifer flow behaviour. The temperature data obtained can be useful for understanding the groundwater flow, which is of particular importance in waste disposal studies. Satellite images of surface temperature and a temperature–time curve were implemented in a heat transport model. Results indicate that conduction plays a major role in the aquifer and support the usefulness of temperature measurements.
Tunde Olarinoye, Tom Gleeson, and Andreas Hartmann
Hydrol. Earth Syst. Sci., 26, 5431–5447, https://doi.org/10.5194/hess-26-5431-2022, https://doi.org/10.5194/hess-26-5431-2022, 2022
Short summary
Short summary
Analysis of karst spring recession is essential for management of groundwater. In karst, recession is dominated by slow and fast components; separating these components is by manual and subjective approaches. In our study, we tested the applicability of automated streamflow recession extraction procedures for a karst spring. Results showed that, by simple modification, streamflow extraction methods can identify slow and fast components: derived recession parameters are within reasonable ranges.
Min Lu, Bart Rogiers, Koen Beerten, Matej Gedeon, and Marijke Huysmans
Hydrol. Earth Syst. Sci., 26, 3629–3649, https://doi.org/10.5194/hess-26-3629-2022, https://doi.org/10.5194/hess-26-3629-2022, 2022
Short summary
Short summary
Lowland rivers and shallow aquifers are closely coupled. We study their interactions here using a combination of impulse response modeling and hydrological data analysis. The results show that the lowland catchments are groundwater dominated and that the hydrological system from precipitation impulse to groundwater inflow response is a very fast response regime. This study also provides an alternative method to estimate groundwater inflow to rivers from the perspective of groundwater level.
Zhongxia Li, Junwei Wan, Tao Xiong, Hongbin Zhan, Linqing He, and Kun Huang
Hydrol. Earth Syst. Sci., 26, 3359–3375, https://doi.org/10.5194/hess-26-3359-2022, https://doi.org/10.5194/hess-26-3359-2022, 2022
Short summary
Short summary
Four permeable rocks with different pore sizes were considered to provide experimental evidence of Forchheimer flow and the transition between different flow regimes. The mercury injection technique was used to measure the pore size distribution, which is an essential factor for determining the flow regime, for four permeable stones. Finally, the influences of porosity and particle size on the Forchheimer coefficients were discussed.
Andreas Wunsch, Tanja Liesch, Guillaume Cinkus, Nataša Ravbar, Zhao Chen, Naomi Mazzilli, Hervé Jourde, and Nico Goldscheider
Hydrol. Earth Syst. Sci., 26, 2405–2430, https://doi.org/10.5194/hess-26-2405-2022, https://doi.org/10.5194/hess-26-2405-2022, 2022
Short summary
Short summary
Modeling complex karst water resources is difficult enough, but often there are no or too few climate stations available within or close to the catchment to deliver input data for modeling purposes. We apply image recognition algorithms to time-distributed, spatially gridded meteorological data to simulate karst spring discharge. Our models can also learn the approximate catchment location of a spring independently.
Brian Berkowitz
Hydrol. Earth Syst. Sci., 26, 2161–2180, https://doi.org/10.5194/hess-26-2161-2022, https://doi.org/10.5194/hess-26-2161-2022, 2022
Short summary
Short summary
Extensive efforts have focused on quantifying conservative chemical transport in geological formations. We assert that an explicit accounting of temporal information, under uncertainty, in addition to spatial information, is fundamental to an effective modeling formulation. We further assert that efforts to apply chemical transport equations at large length scales, based on measurements and model parameter values relevant to significantly smaller length scales, are an unattainable
holy grail.
Guilherme E. H. Nogueira, Christian Schmidt, Daniel Partington, Philip Brunner, and Jan H. Fleckenstein
Hydrol. Earth Syst. Sci., 26, 1883–1905, https://doi.org/10.5194/hess-26-1883-2022, https://doi.org/10.5194/hess-26-1883-2022, 2022
Short summary
Short summary
In near-stream aquifers, mixing between stream water and ambient groundwater can lead to dilution and the removal of substances that can be harmful to the water ecosystem at high concentrations. We used a numerical model to track the spatiotemporal evolution of different water sources and their mixing around a stream, which are rather difficult in the field. Results show that mixing mainly develops as narrow spots, varying In time and space, and is affected by magnitudes of discharge events.
Jacques Bodin, Gilles Porel, Benoît Nauleau, and Denis Paquet
Hydrol. Earth Syst. Sci., 26, 1713–1726, https://doi.org/10.5194/hess-26-1713-2022, https://doi.org/10.5194/hess-26-1713-2022, 2022
Short summary
Short summary
Assessment of the karst network geometry is an important challenge in the accurate modeling of karst aquifers. In this study, we propose an approach for the identification of effective three-dimensional discrete karst conduit networks conditioned on tracer tests and geophysical data. The applicability of the proposed approach is illustrated through a case study at the Hydrogeological Experimental Site in Poitiers, France.
Zexuan Xu, Rebecca Serata, Haruko Wainwright, Miles Denham, Sergi Molins, Hansell Gonzalez-Raymat, Konstantin Lipnikov, J. David Moulton, and Carol Eddy-Dilek
Hydrol. Earth Syst. Sci., 26, 755–773, https://doi.org/10.5194/hess-26-755-2022, https://doi.org/10.5194/hess-26-755-2022, 2022
Short summary
Short summary
Climate change could change the groundwater system and threaten water supply. To quantitatively evaluate its impact on water quality, numerical simulations with chemical and reaction processes are required. With the climate projection dataset, we used the newly developed hydrological and chemical model to investigate the movement of contaminants and assist the management of contamination sites.
Esther Brakkee, Marjolein H. J. van Huijgevoort, and Ruud P. Bartholomeus
Hydrol. Earth Syst. Sci., 26, 551–569, https://doi.org/10.5194/hess-26-551-2022, https://doi.org/10.5194/hess-26-551-2022, 2022
Short summary
Short summary
Periods of drought often lead to groundwater shortages in large regions, which cause damage to nature and the economy. To take measures, we need a good understanding of where and when groundwater shortage occurs. In this study, we have tested a method that can combine large amounts of groundwater measurements in an automated way and provide detailed maps of how groundwater shortages develop during a drought period. This information can help water managers to limit future groundwater shortages.
Emmanuel Dubois, Marie Larocque, Sylvain Gagné, and Guillaume Meyzonnat
Hydrol. Earth Syst. Sci., 25, 6567–6589, https://doi.org/10.5194/hess-25-6567-2021, https://doi.org/10.5194/hess-25-6567-2021, 2021
Short summary
Short summary
This work demonstrates the relevance of using a water budget model to understand long-term transient and regional-scale groundwater recharge (GWR) in cold and humid climates where groundwater observations are scarce. Monthly GWR is simulated for 57 years on 500 m x 500 m cells in Canada (36 000 km2 area) with limited uncertainty due to a robust automatic calibration method. The increases in precipitation and temperature since the 1960s have not yet produced significant changes in annual GWR.
Yaniv Edery, Martin Stolar, Giovanni Porta, and Alberto Guadagnini
Hydrol. Earth Syst. Sci., 25, 5905–5915, https://doi.org/10.5194/hess-25-5905-2021, https://doi.org/10.5194/hess-25-5905-2021, 2021
Short summary
Short summary
The interplay between dissolution, precipitation and transport is widely encountered in porous media, from CO2 storage to cave formation in carbonate rocks. We show that dissolution occurs along preferential flow paths with high hydraulic conductivity, while precipitation occurs at locations close to yet separated from these flow paths, thus further funneling the flow and changing the probability density function of the transport, as measured on the altered conductivity field at various times.
Cited articles
Anderson, M., Woessner, W. W., and Hunt, R.: Applied Groundwater Modeling:
Simulation of Flow and Advective Transport, 2nd Edn., Elsevier, 2015.
Appelo, C. A. J. and Postma, D.: Geochemistry, Groundwater and Pollution,
Balkema Publishers, Amsterdam, 2005.
Bethke, C. M. and Johnson, T. M.: Paradox of groundwater age, Geology, 30,
107–110, https://doi.org/10.1130/0091-7613(2002)030<0107:POGA>2.0.CO;2,
2002.
Bethke, C. M. and Johnson, T. M.: Groundwater Age and Groundwater Age Dating,
Annu. Rev. Earth Pl. Sc., 36, 121–152,
https://doi.org/10.1146/annurev.earth.36.031207.124210, 2008.
Boaretto, E., Thorling, L., Sveinbjörnsdóttir, Á. E., Yechieli, Y., and
Heinemeier, J.: Study of the effect of fossil organic carbon on 14C in
groundwater from Hvinningdal, Denmark, in: Proceedings of the 16th
International 14C Conference, vol. 40, edited by: Mook, W. G. and van der
Plicht, J., 915–920, 1998.
Bohlke, J. K. and Denver, J. M.: Combined use of ground- water dating,
chemical, and isotopic analyses to resolve the history and fate of nitrate
contamination in two agricultural watersheds, atlantic coastal Plain,
Maryland, Water Resour. Res., 31, 2319–2339, https://doi.org/10.1029/95WR01584, 1995.
Campana, M. E. and Simpson, E. S.: Groundwater residence times and recharge
rates using a discrete-state compartment model and 14C data, J. Hydrol., 72,
171–185, https://doi.org/10.1016/0022-1694(84)90190-2, 1984.
Castro, M. C. and Goblet, P.: Calibration of regional groundwater flow
models: Working toward a better understanding of site-specific systems, Water
Resour. Res., 39, 1172, https://doi.org/10.1029/2002WR001653, 2003.
Castro, M. C. and Goblet, P.: Calculation of ground water ages-a comparative
analysis, Groundwater, 43, 368–380, https://doi.org/10.1111/j.1745-6584.2005.0046.x,
2005.
Cook, P. G. and Herczeg, A. L.: Environmental tracers in subsurface
hydrology, Springer Science and Business, 2000.
Cornaton, F. J.: Transient water age distributions in environmental flow
systems: The time-marching Laplace transform solution technique, Water
Resour. Res., 48, 1–17, https://doi.org/10.1029/2011WR010606, 2012.
de Dreuzy, J.-R. and Ginn, T. R.: Residence times in subsurface hydrological
systems, introduction to the Special Issue, J. Hydrol., 543, 1–6,
https://doi.org/10.1016/j.jhydrol.2016.11.046, 2016.
Delsman, J. R., Hu-a-ng, K. R. M., Vos, P. C., de Louw, P. G. B., Oude
Essink, G. H. P., Stuyfzand, P. J., and Bierkens, M. F. P.: Paleo-modeling of
coastal saltwater intrusion during the Holocene: an application to the
Netherlands, Hydrol. Earth Syst. Sci., 18, 3891–3905,
https://doi.org/10.5194/hess-18-3891-2014, 2014.
Doherty, J.: Calibration and uncertainty analysis for complex environmental
models, Wartermark Numerical Computing, Brisbane, Australia, ISBN: 978-0-9943786-0-6, 2015.
Doherty, J.: Model-Independent Parameter Estimation I, Watermark Numerical
Computing, 366, available at:
http://www.pesthomepage.org/Downloads.php (last access: 1 August 2017),
2016.
Doherty, J. and Hunt, R. J.: Two statistics for evaluating parameter
identifiability and error reduction, J. Hydrol., 366, 119–127,
https://doi.org/10.1016/j.jhydrol.2008.12.018, 2009.
Eberts, S. M., Böhlke, J. K., Kauffman, L. J., and Jurgens, B. C.:
Comparison of particle-tracking and lumped-parameter age-distribution models
for evaluating vulnerability of production wells to contamination, Hydrogeol.
J., 20, 263–282, https://doi.org/10.1007/s10040-011-0810-6, 2012.
Edmunds, W. M. and Smedley, P. L.: Residence time indicators in groundwater:
The East Midlands Triassic sandstone aquifer, Appl. Geochem., 15, 737–752,
https://doi.org/10.1016/S0883-2927(99)00079-7, 2000.
Engesgaard, P. and Molson, J.: Direct simulation of ground water age in the
Rabis Creek Aquifer, Denmark, Ground Water, 36, 577–582,
https://doi.org/10.1111/j.1745-6584.1998.tb02831.x, 1998.
Freeze, R. A. and Cherry, J. A.: Groundwater, Prentice-Hall, ISBN
9780133653120,
1979.
Gelhar, L. W., Welty, C., and Rehfeldt, K. R.: A Critical Review of Data on
Field-Scale Dispersion in Aquifers, Water Resour. Res., 28, 1955–1974,
https://doi.org/10.1029/92WR00607, 1992.
Ginn, T. R., Haeri, H., Massoudieh, A., and Foglia, L.: Notes on groundwater
age in forward and inverse modeling, Transport Porous Med., 79, 117–134,
https://doi.org/10.1007/s11242-009-9406-1, 2009.
Gleeson, T., Befus, K. M., Jasechko, S., Luijendijk, E., and Cardenas, M. B.:
The global volume and distribution of modern groundwater, Nat. Geosci., 9,
161–167, https://doi.org/10.1038/ngeo2590, 2015.
Goderniaux, P., Davy, P., Bresciani, E., De Dreuzy, J. R., and Le Borgne, T.:
Partitioning a regional groundwater flow system into shallow local and deep
regional flow compartments, Water Resour. Res., 49, 2274–2286,
https://doi.org/10.1002/wrcr.20186, 2013.
Goode, J. D.: Direct Simulation of Groundwater age, Water Resour. Res., 32,
289–296, 1996.
Guo, W. and Langevin, C. D.: User's Guide to SEAWAT: A Computer Program For
Simulation of Three-Dimensional Variable-Density Ground-Water Flow,
Tallahassee, 2002.
Hansen, B., Dalgaard, T., Thorling, L., Sørensen, B., and Erlandsen, M.:
Regional analysis of groundwater nitrate concentrations and trends in Denmark
in regard to agricultural influence, Biogeosciences, 9, 3277–3286,
https://doi.org/10.5194/bg-9-3277-2012, 2012.
Harbaugh, A. W., Banta, E. R., Hill, M. C., and McDonald, M. G.:
MODFLOW-2000, The U. S. Geological Survey modular ground-water model-user
guide to modularization concepts and the ground-water flow process, USGS
Open-File Rep. 00-92, 2000.
Harkness, J. S., Darrah, T. H., Warner, N. R., Whyte, C. J., Moore, M. T.,
Millot, R., Kloppmann, W., Jackson, R. B., and Vengosh, A.: The geochemistry
of naturally occurring methane and saline groundwater in an area of
unconventional shale gas development, Geochim. Cosmochim. Ac., 208, 302–334,
https://doi.org/10.1016/j.gca.2017.03.039, 2017.
Harris, K. R. and Woolf, L. A.: Pressure and temperature dependence of the
self diffusion coefficient of water and oxygen-18 water, J. Chem. Soc.
Faraday Trans., 76, 377–385, https://doi.org/10.1039/f19807600377, 1980.
Harvey, C. F. and Gorelick, S. M.: Temporal moment-generating equations:
Modeling transport and mass transfer in heterogenous aquifers, Water Resour.
Manag., 31, 1895–1911, 1995.
Henriksen, H. J., Troldborg, L., Nyegaard, P., Sonnenborg, T. O., Refsgaard,
J. C., and Madsen, B.: Methodology for construction, calibration and
validation of a national hydrological model for Denmark, J. Hydrol., 280,
52–71, https://doi.org/10.1016/S0022-1694(03)00186-0, 2003.
Hill, M. C. and Tiedeman, C. R.: Effective Groundwater Model Calibration:
with analysis of data, sensitivities, predictions and uncertainties, Wiley,
2007.
Hinsby, K. and Rasmussen, E. S.: The Miocene sand aquifers, Jutland, Denmark,
in: Natural groundwater quality, edited by: Edmunds, W. M. and Shand, P.,
Blackwell, 2008.
Hinsby, K., Harrar, W. G., Nyegaard, P., Konradi, P. B., Rasmussen, E. S.,
Bidstrup, T., Gregersen, U., and Boaretto, E.: The Ribe Formation in western
Denmark – Holocene and Pleistocene groundwaters in a coastal Miocene sand
aquifer, Geol. Soc. London, Spec. Publ. 189, 29–48,
https://doi.org/10.1144/GSL.SP.2001.189.01.04, 2001a.
Hinsby, K., Edmunds, W. M., Loosli, H. H., Manzano, M., Condesso De Melo, M.
T., and Barbecot, F.: The modern water interface: recognition, protection and
development – advance of modern waters in European aquifer systems, Geol.
Soc. London, Spec. Publ., 189, 271–288, https://doi.org/10.1144/gsl.sp.2001.189.01.16,
2001b.
Hinsby, K., Purtschert, R. and Edmunds, W. M.: Groundwater age and quality,
in: Groundwater Science and Policy, edited by: Quevauviller, P., Royal
Society of Chemistry, London, 2007.
Hölting, B. and Coldewey, W. G.: Hydrogeologie, 8th Edn., Springer-Verlag,
Berin, Heidelberg, 2013.
Høyer, A.-S., Vignoli, G., Hansen, T. M., Vu, L. T., Keefer, D. A., and
Jørgensen, F.: Multiple-point statistical simulation for hydrogeological
models: 3-D training image development and conditioning strategies, Hydrol.
Earth Syst. Sci., 21, 6069–6089, https://doi.org/10.5194/hess-21-6069-2017,
2017.
IAEA: Isotope Methods for Dating Old Groundwater, Internation Atomic Agency,
Vienna, 2013.
Jaehne, B., Heinz, G., and Dietrich, W.: Measurement of the diffusion
coefficients of sparingly soluble gases in water, J. Geophys. Res., 92,
10767–10776, 1987.
Jasechko, S., Perrone, D., Befus, K. M., Cardenas, M. B., Ferguson, G.,
Gleeson, T., Luijendijk, E., McDonnell, J. J., Taylor, R. G., Wada, Y., and
Kirchner, J. W.: Global aquifers dominated by fossil groundwaters but wells
vulnerable to modern contamination, Nat. Geosci., 10, 425–429,
https://doi.org/10.1038/ngeo2943, 2017.
Jørgensen, F., Høyer, A.-S., Sandersen, P. B. E., He, X., and Foged,
N.: Combining 3D geological modelling techniques to address variations in
geology, data type and density – An example from Southern Denmark, Comput.
Geosci., 81, 53–63, https://doi.org/10.1016/j.cageo.2015.04.010, 2015.
Karlsson, I. B., Sonnenborg, T. O., Jensen, K. H., and Refsgaard, J. C.:
Historical trends in precipitation and stream discharge at the Skjern River
catchment, Denmark, Hydrol. Earth Syst. Sci., 18, 595–610,
https://doi.org/10.5194/hess-18-595-2014, 2014.
Kazemi, G. A., Lehr, J. H., and Perrochet, P.: Groundwater Age, Wiley –
Interscience, https://doi.org/0.1002/0471929514, 2006.
Konikow, L. F., Hornberger, G. Z., Putnam, L. D., Shapiro, A. M., and Zinn,
B. A.: The use of groundwater age as a calibration target, in: Proceedings of
ModelCare: Calibration and Reliability in Groundwater Modelling: Credibility
of Modelling, IAHS, 250–256, 2008.
LaBolle, E. M. and Fogg, G. E.: Role of Molecular Diffusion in Contaminant
Migration and Recovery in an Alluvial Aquifer System, Transport Porous Med.,
42, 155–179, https://doi.org/10.1023/A:1006772716244, 2001.
Larsen, F., Tran, L. V., Van Hoang, H., Tran, L. T., Christiansen, A. V., and
Pham, N. Q.: Groundwater salinity influenced by Holocene seawater trapped in
incised valleys in the Red River delta plain, Nat. Geosci., 10, 376–381,
https://doi.org/10.1038/ngeo2938, 2017.
Levenspiel, O. and Sater, V. E.: Two-phase flow in packed beds, I EC Fundam.,
5, 86–92, 1966.
MacDonald, A. M., Bonsor, H. C., Ahmed, K. M., Burgess, W. G., Basharat, M.,
Calow, R. C., Dixit, A., Foster, S. S. D., Gopal, K., Lapworth, D. J., Lark,
R. M., Moench, M., Mukherjee, A., Rao, M. S., Shamsudduha, M., Smith, L.,
Taylor, R. G., Tucker, J., van Steenbergen, F., and Yadav, S. K.: Groundwater
quality and depletion in the Indo-Gangetic Basin mapped from in situ
observations, Nat. Geosci., 9, 762–766, https://doi.org/10.1038/ngeo2791, 2016.
Maloszewski, P. and Zuber, A.: Lumped parameter modles for the interpretation
of environmental tracer data, in: Manual on Mathematical Models in Isotope
Hydrology, IAEA-TECDOC 910, 9–50, 1996.
Manning, A. H., Solomon, D. K., and Thiros, S. A.: 3 H/ 3 He Age Data in
Assessing the Susceptibility of Wells to Contamination, Ground Water, 43,
353–367, https://doi.org/10.1111/j.1745-6584.2005.0028.x, 2005.
McCallum, J. L., Cook, P. G., Simmons, C. T., and Werner, A. D.: Bias of
Apparent Tracer Ages in Heterogeneous Environments, Groundwater, 52,
239–250, https://doi.org/10.1111/gwat.12052, 2014.
McCallum, J. L., Cook, P. G., and Simmons, C. T.: Limitations of the Use of
Environmental Tracers to Infer Groundwater Age, Groundwater, 53, 56–70,
https://doi.org/10.1111/gwat.12237, 2015.
McMahon, P. B., Carney, C. P., Poeter, E. P., and Peterson, S. M.: Use of
geochemical, isotopic, and age tracer data to develop models of groundwater
flow for the purpose of water management, northern High Plains aquifer, USA,
Appl. Geochem., 25, 910–922, https://doi.org/10.1016/j.apgeochem.2010.04.001, 2010.
Meyer, R.: Large scale hydrogeological modelling of a low-lying complex
coastal aquifer system, University of Copenhagen, 184 pp., 2018.
Meyer, R., Engesgaard, P., Høyer, A.-S., Jørgensen, F., Vignoli, G.,
and Sonnenborg, T. O.: Regional flow in a complex coastal aquifer system:
combining voxel geological modelling with regularized calibration, J.
Hydrol., 562, 544–563, https://doi.org/10.1016/j.jhydrol.2018.05.020, 2018a.
Meyer, R., Engesgaard, P., and Sonnenborg, T. O.: Origin and dynamics of
saltwater intrusions in regional aquifers; combining 3D saltwater modelling
with geophysical and geochemical data, Water Resour. Res., in review,
2018b.
Molson, J. W. and Frind, E. O.: On the use of mean groundwater age, life
expectancy and capture probability for defining aquifer vulnerability and
time-of-travel zones for source water protection, J. Contam. Hydrol., 127,
76–87, https://doi.org/10.1016/j.jconhyd.2011.06.001, 2012.
Morgan, L. K., Werner, A. D., and Simmons, C. T.: On the interpretation of
coastal aquifer water level trends and water balances: A precautionary note,
J. Hydrol., 470–471, 280–288, https://doi.org/10.1016/j.jhydrol.2012.09.001, 2012.
Oude Essink, G. H. P., Van Baaren, E. S., and De Louw, P. G. B.: Effects of
climate change on coastal groundwater systems: A modeling study in the
Netherlands, Water Resour. Res., 46, 1–16, https://doi.org/10.1029/2009WR008719, 2010.
Park, J., Bethke, C. M., Torgersen, T., and Johnson, T. M.: Transport
modeling applied to the interpretation of groundwater 36 Cl age, Water
Resour. Res., 38, 1–15, https://doi.org/10.1029/2001WR000399, 2002.
Partington, D., Brunner, P., Simmons, C. T., Therrien, R., Werner, A. D.,
Dandy, G. C., and Maier, H. R.: A hydraulic mixing-cell method to quantify
the groundwater component of streamflow within spatially distributed fully
integrated surface water-groundwater flow models, Environ. Model. Softw., 26,
886–898, https://doi.org/10.1016/j.envsoft.2011.02.007, 2011.
Pauw, P., De Louw, P. G. B., and Oude Essink, G. H. P.: Groundwater
salinisation in the Wadden Sea area of the Netherlands: Quantifying the
effects of climate change, sea-level rise and anthropogenic interferences,
Neth. J. Geosci., 91, 373–383, https://doi.org/10.1017/S0016774600000500, 2012.
Pearson, F. J. and Hanshaw, B. B.: Sources of Dissolved Carbonate Species in Groundwater and their Effects on Carbon-14 Dating, Symposium on Iostopic Hydrology, International Atomic Energy Agency (IAEA), 1970.
Pollock, D. W.: User Guide for MODPATH Version 6 – A Particle-Tracking Model
for MODFLOW, U.S. Geol. Surv. Tech. Methods 6-A41, 2012.
Post, V. E. A., Vandenbohede, A., Werner, A. D., and Teubner, M. D.:
Groundwater ages in coastal aquifers, Adv. Water Resour., 57, 1–11,
https://doi.org/10.1016/j.advwatres.2013.03.011, 2013.
Post, V. E. A., Kooi, H., and Simmons, C.: Using hydraulic head measurements
in variable-density ground water flow analyses, Ground Water, 45, 664–71,
https://doi.org/10.1111/j.1745-6584.2007.00339.x, 2007.
Rasmussen, E. S., Dybkjær, K., and Piasecki, S.: Lithostratigraphy of the
Upper Oligocene-Miocene succession of Denmark, Geol. Surv. Denmark Greenl.
Bull., 22, ISBN 9788778712912, 2010.
Salmon, S. U., Prommer, H., Park, J., Meredith, K. T., Turner, J. V., and
McCallum, J. L.: A general reactive transport modeling framework for
simulating and interpreting groundwater 14C age and delta 13C, Water Resour.
Res., 51, 359–376, https://doi.org/10.1002/2014WR015779, 2015.
Sanford, W.: Calibration of models using groundwater age, Hydrogeol. J., 19,
13–16, https://doi.org/10.1007/s10040-010-0637-6, 2011.
Sanford, W. E.: Correcting for Diffusion in Carbon-14 Dating of Ground Water,
Ground Water, 35, 357–361, 1997.
Sanford, W. E., Plummer, L. N., McAda, D. P., Bexfield, L. M., and Anderholm,
S. K.: Hydrochemical tracers in the middle Rio Grande Basin, USA: 2.
Calibration of a groundwater-flow model, Hydrogeol. J., 12, 389–407,
https://doi.org/10.1007/s10040-004-0326-4, 2004.
Sanford, W. E., Plummer, L. N., Busenber, G. C., Nelms, D. L., and Schlosser,
P.: Using dual-domain advective-transport simulation to reconcile
multiple-tracer ages and estimate dual-porosity transport parameters, Water
Resour. Res., 53, 5002–5016, https://doi.org/10.1002/2016WR019469,
2017.
Scharling, P. B.: Hydrogeological modeling and multiple environmental tracer
analysis of the deep Miocene aquifers within the Skjern and Varde river
catchment, University of Copenhagen, 2011.
Seifert, D., Sonnenborg, T. O., Scharling, P., and Hinsby, K.: Use of
alternative conceptual models to assess the impact of a buried valley on
groundwater vulnerability, Hydrogeol. J., 16, 659–674,
https://doi.org/10.1007/s10040-007-0252-3, 2008.
Seiler, K. and Lindner, W.: Near-surface and deep groundwaters, J. Hydrol.,
165, 33–44, https://doi.org/10.1016/0022-1694(95)92765-6, 1995.
Smedley, P. L. and Kinniburgh, D. G.: A review of the source, behaviour and
distribution of arsenic in natural waters, Appl. Geochem., 17, 517–568,
https://doi.org/10.1016/S0883-2927(02)00018-5, 2002.
Smedley, P. L. and Kinniburgh, D. G.: Molybdenum in natural waters: A review
of occurrence, distributions and controls, Appl. Geochem., 84, 387–432,
https://doi.org/10.1016/j.apgeochem.2017.05.008, 2017.
Sonnenborg, T. O., Scharling, P. B., Hinsby, K., Rasmussen, E. S., and
Engesgaard, P.: Aquifer Vulnerability Assessment Based on Sequence
Stratigraphic and 39 Ar Transport Modeling, Groundwater, 54, 214–230,
https://doi.org/10.1111/gwat.12345, 2016.
Starn, J. J., Green, C. T., Hinkle, S. R., Bagtzoglou, A. C., and Stolp, B.
J.: Simulating water-quality trends in public-supply wells in transient flow
systems, Ground Water, 52, 53–62, https://doi.org/10.1111/gwat.12230, 2014.
Stroeven, A. P., Hättestrand, C., Kleman, J., Heyman, J., Fabel, D.,
Fredin, O., Goodfellow, B. W., Harbor, J. M., Jansen, J. D., Olsen, L.,
Caffee, M. W., Fink, D., Lundqvist, J., Rosqvist, G. C., Strömberg, B.,
Jansson, K. N.: Deglaciation of Fennoscandia, Quaternary Sci. Rev., 147,
91–121, https://doi.org/10.1016/j.quascirev.2015.09.016, 2016.
Sudicky, E. A. and Frind, E. O.: Carbon 14 dating of groundwater in confined
aquifers: Implications of aquitard diffusion, Water Resour. Res., 17,
1060–1064, https://doi.org/10.1029/WR017i004p01060, 1981.
Tikhonov, A. N. and Arsenin, V. Y.: Solutions of ill-posed problems, Winston,
Washington, DC, 1977.
Tóth, J.: A theoretical analysis of groundwater flow in small drainage
basins, J. Geophys. Res., 68, 4795–4812,
https://doi.org/10.1029/JZ068i016p04795, 1963.
Troldborg, L., Jensen, K. H., Engesgaard, P., Refsgaard, J. C., and Hinsby,
K.: Using Environmental Tracers in Modeling Flow in a Complex Shallow Aquifer
System, J. Hydrol. Eng., 13, 199–204, https://doi.org/10.1061/(ASCE)1084-0699(2008)13:11(1037),
2008.
Turnadge, C. and Smerdon, B. D.: A review of methods for modelling
environmental tracers in groundwater: Advantages of tracer concentration
simulation, J. Hydrol., 519, 3674–3689, https://doi.org/10.1016/j.jhydrol.2014.10.056,
2014.
Varni, M. and Carrera, J.: Simulation of groundwater age distributions, Water
Resour. Res., 34, 3271–3281, https://doi.org/10.1029/98WR02536, 1998.
Weissmann, G. S., Zhang, Y., LaBolle, E. M., and Fogg, G. E.: Dispersion of
groundwater age in an alluvial aquifer system, Water Resour. Res., 38,
16.1–16.13, https://doi.org/10.1029/2001WR000907, 2002.
Wood, C., Cook, P. G., Harrington, G. A., and Knapton, A.: Constraining
spatial variability in recharge and discharge in an arid environment through
modeling carbon-14 with improved boundary conditions, Water Resour. Res., 53,
142–157, https://doi.org/10.1002/2015WR018424, 2017.
Woolfenden, L. R. and Ginn, T. R.: Modeled ground water age distributions,
Ground Water, 47, 547–557, https://doi.org/10.1111/j.1745-6584.2008.00550.x, 2009.
