Articles | Volume 20, issue 7
Research article 29 Jul 2016
Research article | 29 Jul 2016
Application of tritium in precipitation and baseflow in Japan: a case study of groundwater transit times and storage in Hokkaido watersheds
Maksym A. Gusyev et al.
M. A. Gusyev, D. Abrams, M. W. Toews, U. Morgenstern, and M. K. Stewart
Hydrol. Earth Syst. Sci., 18, 3109–3119,
Michael Kilgour Stewart, Uwe Morgenstern, and Ian Cartwright
Hydrol. Earth Syst. Sci. Discuss.,
Revised manuscript under review for HESSShort summary
The combined use of deuterium and tritium to determine travel time distributions in streams is an important development in catchment hydrology (Rodriguez et al, 2021). This comment, however, argues that their results do not generally invalidate the truncation hypothesis of Stewart et al. (2010) (i.e. that stable isotopes underestimate travel times through catchments) as they imply, but asserts instead that the hypothesis still applies to many other catchments.
Michael Kilgour Stewart and Philippa Lauren Aitchison-Earl
Hydrol. Earth Syst. Sci., 24, 3583–3601,Short summary
This paper is important for water resource management, being concerned with irrigation return flow causing
hotspotsin nitrate concentrations in groundwater and
denitrification imprintswhere nitrate concentrations are reduced by denitrification although the dissolved oxygen concentration is not low. The work is highly significant for modelling of nitrate transport through soil–groundwater systems, for understanding denitrification processes, and for managing fertilizer application to land.
William Howcroft, Ian Cartwright, and Uwe Morgenstern
Hydrol. Earth Syst. Sci., 22, 635–653,Short summary
Documenting mean transit times is critical for understanding and managing catchments. Mean transit times in six headwater catchments of the Otway Ranges, Australia, determined using tritium, range from 7 to 230 years. Tritium activities correlate well with streamflow but are difficult to predict from catchment attributes or major ion geochemistry. The long mean transit times suggest that the catchments are buffered from short-term rainfall variations.
Michael K. Stewart, Uwe Morgenstern, Maksym A. Gusyev, and Piotr Małoszewski
Hydrol. Earth Syst. Sci., 21, 4615–4627,Short summary
This paper presents for the first time the effects of aggregation errors on mean transit times and young fractions estimated using tritium concentrations. Such errors, due to heterogeneity in catchments, had previously been demonstrated for seasonal tracer cycles by Kirchner (2016a). We found that mean transit times derived from tritium are just as susceptible to aggregation bias as those from seasonal tracer cycles. Young fractions were found to be almost immune to aggregation bias.
Monique Beyer, Uwe Morgenstern, Rob van der Raaij, and Heather Martindale
Hydrol. Earth Syst. Sci., 21, 4213–4231,Short summary
The determination of groundwater age can aid characterization of aquifers, providing information on groundwater mixing, flow, volume, and recharge rates. Here we assess a recently discovered groundwater age tracer, Halon-1301. Its performance as an age tracer is assessed against six other well-established, widely used age tracers in 302 groundwater samples. We show Halon-1301 reliably inferred age, thus potentially becoming a useful groundwater age tracer where other tracers are compromised.
Ian Cartwright and Uwe Morgenstern
Hydrol. Earth Syst. Sci., 20, 4757–4773,Short summary
This research used tritium to determine the timescales that water is stored in peatlands and eucalyptus forest catchments in upland river systems in southeast Australia. The mean transit times in the peatland catchments of less than a few years contrast with much longer transit times (years to decades) in adjacent eucalyptus catchments. The peat is susceptible to drying which renders it vulnerable to degradation and bushfire and does not represent a long-term water store to upland streams.
C. Duvert, M. K. Stewart, D. I. Cendón, and M. Raiber
Hydrol. Earth Syst. Sci., 20, 257–277,Short summary
The transit time of water is a key indicator of hydrological processes at the catchment scale. Our results suggest that the use of tritium time series in streamwater can be highly valuable for assessing the temporal variations in the transit time of older groundwater contributions to streamflow. We also show that, shortly after high flow events, the transit time of the old water fraction increases and tends to approach the groundwater residence time.
I. Cartwright and U. Morgenstern
Hydrol. Earth Syst. Sci., 19, 3771–3785,Short summary
This study documents the age of water that contributes to rivers in upper catchments using the radioactive tracer tritium. River water in the upper Ovens Valley (Australia) is several years to decades old and water from different parts of the catchment (e.g., soil, regolith, and groundwater) is mobilised at different flow conditions. The results indicate that these rivers are buffered against short term climate variability but are susceptible to longer-term climate and land use changes
T. Sayama, Y. Tatebe, Y. Iwami, and S. Tanaka
Nat. Hazards Earth Syst. Sci., 15, 1617–1630,Short summary
In 2011 the Chao Phraya River basin received about 1400mm rainfall, which was 1.2 times more than past large floods in 1995 and 2006. The long-term rainfall-runoff-inundation simulation and its water balance analysis revealed high elasticity in the flood inundation volume (4.2%). 1.2 times more rainfall might result in 1.6 times more flood inundation volume in 2011. The high sensitivity of inundation should be well recognized for a better understanding of the flood hazard characteristics.
M. Beyer, R. van der Raaij, U. Morgenstern, and B. Jackson
Hydrol. Earth Syst. Sci., 19, 2775–2789,Short summary
We assess the potential of Halon-1301 as a new groundwater age tracer, which had not been assessed in detail. We determine Halon-1301 and infer age in 17 New Zealand groundwater samples and various modern waters. Halon-1301 reliably inferred age in 71% of the sites within 1 SD of the ages inferred from tritium and SF6. The remaining (anoxic) waters show reduced concentrations of Halon-1301 along with even further reduced concentrations of CFCs. The reason(s) for this need to be further assessed.
S. Kang, F. Wang, U. Morgenstern, Y. Zhang, B. Grigholm, S. Kaspari, M. Schwikowski, J. Ren, T. Yao, D. Qin, and P. A. Mayewski
The Cryosphere, 9, 1213–1222,
M. A. Gusyev, Y. Kwak, M. I. Khairul, M. B. Arifuzzaman, J. Magome, H. Sawano, and K. Takeuchi
Proc. IAHS, 370, 75–81,
Y. Kwak, M. Gusyev, B. Arifuzzaman, I. Khairul, Y. Iwami, and K. Takeuchi
Proc. IAHS, 370, 83–87,Short summary
This study consists of two parts in the issue of flood change: hazard assessment (Part 1) and risk assessment (Part 2). Part 2 focuses on estimating nationwide flood risk in terms of affected people and rice crop damage due to a 50-year flood hazard and quantifying flood risk changes. The preliminary results show that a tendency of flood risk change strongly depends on the temporal and spatial dynamics of exposure and vulnerability such as distributed population and effectiveness of water infra.
M. K. Stewart
Hydrol. Earth Syst. Sci., 19, 2587–2603,Short summary
This paper presents new baseflow separation and recession analysis methods for streamflow. The baseflow separation method ("bump and rise method" or BRM) aims to accurately simulate the shape of tracer-determined baseflow or pre-event water. The recession analysis approach advocates analyzing quickflow and baseflow as well as streamflow because analyzing the latter alone gives misleading information on catchment storage reservoirs. The methods are demonstrated for the Glendhu streamflow record.
U. Morgenstern, C. J. Daughney, G. Leonard, D. Gordon, F. M. Donath, and R. Reeves
Hydrol. Earth Syst. Sci., 19, 803–822,
M. A. Gusyev, D. Abrams, M. W. Toews, U. Morgenstern, and M. K. Stewart
Hydrol. Earth Syst. Sci., 18, 3109–3119,
M. A. Gusyev, M. Toews, U. Morgenstern, M. Stewart, P. White, C. Daughney, and J. Hadfield
Hydrol. Earth Syst. Sci., 17, 1217–1227,
Related subject area
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forcing and groundwater recharge on the growth of a fresh groundwater lens in a mega-scale beach nourishment
Karina Y. Gutierrez-Jurado, Daniel Partington, and Margaret Shanafield
Hydrol. Earth Syst. Sci., 25, 4299–4317,Short summary
Understanding the hydrologic cycle in semi-arid landscapes includes knowing the physical processes that govern where and why rivers flow and dry within a given catchment. To gain this understanding, we put together a conceptual model of what processes we think are important and then tested that model with numerical analysis. The results broadly confirmed our hypothesis that there are three distinct regions in our study catchment that contribute to streamflow generation in quite different ways.
Natascha Brandhorst, Daniel Erdal, and Insa Neuweiler
Hydrol. Earth Syst. Sci., 25, 4041–4059,Short summary
We compare two approaches for coupling a 2D groundwater model with multiple 1D models for the unsaturated zone. One is non-iterative and very fast. The other one is iterative and involves a new way of treating the specific yield, which is crucial for obtaining a consistent solution in both model compartments. Tested on different scenarios, this new method turns out to be slower than the non-iterative approach but more accurate and still very efficient compared to fully integrated 3D model runs.
Vince P. Kaandorp, Hans Peter Broers, Ype van der Velde, Joachim Rozemeijer, and Perry G. B. de Louw
Hydrol. Earth Syst. Sci., 25, 3691–3711,Short summary
We reconstructed historical and present-day tritium, chloride, and nitrate concentrations in stream water of a catchment using land-use-based input curves and calculated travel times of groundwater. Parameters such as the unsaturated zone thickness, mean travel time, and input patterns determine time lags between inputs and in-stream concentrations. The timescale of the breakthrough of pollutants in streams is dependent on the location of pollution in a catchment.
Yueling Ma, Carsten Montzka, Bagher Bayat, and Stefan Kollet
Hydrol. Earth Syst. Sci., 25, 3555–3575,Short summary
This study utilized spatiotemporally continuous precipitation anomaly (pra) and water table depth anomaly (wtda) data from integrated hydrologic simulation results over Europe in combination with Long Short-Term Memory (LSTM) networks to capture the time-varying and time-lagged relationship between pra and wtda in order to obtain reliable models to estimate wtda at the individual pixel level.
Raoul A. Collenteur, Mark Bakker, Gernot Klammler, and Steffen Birk
Hydrol. Earth Syst. Sci., 25, 2931–2949,Short summary
This study explores the use of nonlinear transfer function noise (TFN) models to simulate groundwater levels and estimate groundwater recharge from observed groundwater levels. A nonlinear recharge model is implemented in a TFN model to compute the recharge. The estimated recharge rates are shown to be in good agreement with the recharge observed with a lysimeter present at the case study site in Austria. The method can be used to obtain groundwater recharge rates at sub-yearly timescales.
Franci Gabrovšek and Wolfgang Dreybrodt
Hydrol. Earth Syst. Sci., 25, 2895–2913,Short summary
The evolution of karst aquifers is often governed by solutions gaining their aggressiveness in depth. Although the principles of
hypogene speleogenesisare known, modelling studies based on reactive flow in fracture networks are missing. We present a model where dissolution at depth is triggered by the mixing of waters of different origin and chemistry. We show how the initial position of the mixing zone and flow instabilities therein determine the position and shape of the final conduits.
Patrick Morrissey, Paul Nolan, Ted McCormack, Paul Johnston, Owen Naughton, Saheba Bhatnagar, and Laurence Gill
Hydrol. Earth Syst. Sci., 25, 1923–1941,Short summary
Lowland karst aquifers provide important wetland habitat resulting from seasonal flooding on the land surface. This flooding is controlled by surcharging of the karst system, which is very sensitive to changes in rainfall. This study investigates the predicted impacts of climate change on a lowland karst catchment in Ireland and highlights the relative vulnerability to future changing climate conditions of karst systems and any associated wetland habitats.
Liwen Wu, Jesus D. Gomez-Velez, Stefan Krause, Anders Wörman, Tanu Singh, Gunnar Nützmann, and Jörg Lewandowski
Hydrol. Earth Syst. Sci., 25, 1905–1921,Short summary
With a physically based model that couples flow and heat transport in hyporheic zones, the present study provides the first insights into the dynamics of hyporheic responses to the impacts of daily groundwater withdrawal and river temperature fluctuations, allowing for a better understanding of transient hyporheic exchange processes and hence an improved pumping operational scheme.
Andreas Wunsch, Tanja Liesch, and Stefan Broda
Hydrol. Earth Syst. Sci., 25, 1671–1687,
Jost Hellwig, Michael Stoelzle, and Kerstin Stahl
Hydrol. Earth Syst. Sci., 25, 1053–1068,Short summary
Potential future groundwater and baseflow drought hazards depend on systems' sensitivity to altered recharge conditions. With three generic scenarios, we found different sensitivities across Germany driven by hydrogeology. While changes in drought hazard due to seasonal recharge shifts will be rather low, a lengthening of dry spells could cause stronger responses in regions with slow groundwater response to precipitation, urging local water management to prepare for more severe droughts.
Martin J. Wells, Troy E. Gilmore, Natalie Nelson, Aaron Mittelstet, and John K. Böhlke
Hydrol. Earth Syst. Sci., 25, 811–829,Short summary
Groundwater in many agricultural areas contains high levels of nitrate, which is a concern for drinking water supplies. The rate at which nitrate moves through the subsurface is a critical piece of information for predicting how quickly groundwater nitrate levels may improve after agricultural producers change their approach to managing crop water and fertilizers. In this study, we explored a new statistical modeling approach to determine rates at which nitrate moves into and through an aquifer.
Arnaud Duranel, Julian R. Thompson, Helene Burningham, Philippe Durepaire, Stéphane Garambois, Robert Wyns, and Hervé Cubizolle
Hydrol. Earth Syst. Sci., 25, 291–319,Short summary
Peat-forming wetlands (mires) provide multiple ecosystem services, which depend on peat remaining waterlogged. Using hydrological modelling, we show that, contrary to a common assumption, groundwater inflow can be a quantitatively important and functionally critical element of the water balance of mires in hard-rock upland and mountain areas. This influence is such that patterns of groundwater upwelling and seepage explain the spatial distribution of mires in the landscape.
Ming Wu, Jianfeng Wu, Jichun Wu, and Bill X. Hu
Hydrol. Earth Syst. Sci., 24, 5903–5917,Short summary
A new criterion (χi) is proposed to estimate representative elementary volume (REV) of a translucent material based on light transmission techniques. This study is essential for quantitative investigation of the scale effect of porous media and contaminant transformation. The fluid and contaminant migration and transform in porous media can be simulated accurately according to the REV estimation results using the light transmission technique and the appropriate criterion χi.
Ali Ghaseminejad and Venkatesh Uddameri
Hydrol. Earth Syst. Sci., 24, 5759–5779,Short summary
While artificial neural networks (ANNs) have been used to forecast groundwater levels at single wells, they have not been constructed to forecast hydraulic heads in both space and time. This seminal study presents a modeling framework, guided by the governing physical laws, for building an integrated space–time ANN (IST–ANN) model for regional groundwater level predictions. IST–ANN shows promise for parsimoniously modeling regional-scale groundwater levels using available surrogate information.
Marie-Amélie Pétré, Bernard Ladouche, Jean-Luc Seidel, Romain Hemelsdaël, Véronique de Montety, Christelle Batiot-Guilhe, and Claudine Lamotte
Hydrol. Earth Syst. Sci., 24, 5655–5672,Short summary
We studied the impact of occasional saltwater intrusions into the karst aquifer of the Balaruc peninsula (France). Using hydrogeological and geochemical data, this study shows that the hydraulic impact on the aquifer is rapid and of regional extent, whereas the geochemical impact is observed at the local scale and is temporally persistent. This research supports groundwater management by providing a better understanding of the hydrodynamics and recovery of the aquifer after saltwater intrusions.
Emmanuel Dubois, Joanna Doummar, Séverin Pistre, and Marie Larocque
Hydrol. Earth Syst. Sci., 24, 4275–4290,Short summary
The simulation of flow in a karst aquifer in a Mediterranean region using a semi-distributed linear reservoir model (geometry and parameterization) is calibrated and validated based on the analysis of high-resolution time series. The model is used to predict the effect of climatic variation. Although the spring is highly sensitive to rainfall variations, it is also resilient to warming temperature. Finally, this integrated conceptual method is reproducible for karst in semiarid regions.
Stephen R. Maples, Laura Foglia, Graham E. Fogg, and Reed M. Maxwell
Hydrol. Earth Syst. Sci., 24, 2437–2456,Short summary
In this study, we use a combination of local- and global-sensitivity analyses to evaluate the relative importance of (1) the configuration of subsurface alluvial geology and (2) the hydraulic properties of geologic facies on recharge processes. Results show that there is a large variation of recharge rates possible in a typical alluvial aquifer system and that the configuration proportion of sand and gravel deposits in the subsurface have a large impact on recharge rates.
Jian Song, Yun Yang, Xiaomin Sun, Jin Lin, Ming Wu, Jianfeng Wu, and Jichun Wu
Hydrol. Earth Syst. Sci., 24, 2323–2341,Short summary
We proposed a novel many-objective simulation-optimization framework for conjunctive use of surface water and groundwater in Yanqi Basin, northwest China. The management model involving socioeconomic and environmental objectives was constructed to explore optimal water-use schemes. Three runoff scenarios were then specified to quantify the effect of runoff reduction related to climate change on water management. Results provide Pareto-optimal solutions for basin-scale water management.
Miao Jing, Rohini Kumar, Falk Heße, Stephan Thober, Oldrich Rakovec, Luis Samaniego, and Sabine Attinger
Hydrol. Earth Syst. Sci., 24, 1511–1526,Short summary
This study investigates the response of regional groundwater system to the climate change under three global warming levels (1.5, 2, and 3 °C) in a central German basin. A comprehensive uncertainty analysis is also presented. This study indicates that the variability of responses increases with the amount of global warming, which might affect the cost of managing the groundwater system.
Harald Hofmann, Dean Newborn, Ian Cartwright, Dioni I. Cendón, and Matthias Raiber
Hydrol. Earth Syst. Sci., 24, 1293–1318,Short summary
Fresh groundwater (GW) on barrier islands is affected by GW use and precipitation variability. Mean residence times (MRTs) of GW on a sand barrier island were determined. They ranged from 37 years to more than 150 years for tritium and had a much larger range (modern to 5000 years) for carbon-14. Perched aquifer systems in the unsaturated zone and peat formations around wetlands are the most likely cause of longer MRTs, as they have a significant impact on regional recharge and flow diversion.
Christopher Vincent Henri, Thomas Harter, and Efstathios Diamantopoulos
Hydrol. Earth Syst. Sci., 24, 1189–1209,Short summary
Non-point source contaminations of aquifers are complex to model, predict and manage. This study uses numerical and stochastic methods to address the importance of key sources of spatial variability. We show that heterogeneity in recharge and contaminant loading does not significantly impact management metrics and could be simplified. Also, homogenizing physical properties has more impact on predictions, but can provide useful information on concentration statistics in a regional analysis.
Behzad Ataie-Ashtiani and Craig T. Simmons
Hydrol. Earth Syst. Sci., 24, 761–769,Short summary
We revisit and shed light on the textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji. Ground-breaking ideas and descriptions of hydrological and hydrogeological perceptions such as components of the hydrological cycle, groundwater quality and driving factors for groundwater flow were presented in the book. We speculate that Karaji's book is the first of its kind to provide a construction and maintenance manual for an engineering project.
Zhe Zhang, Yanping Li, Michael Barlage, Fei Chen, Gonzalo Miguez-Macho, Andrew Ireson, and Zhenhua Li
Hydrol. Earth Syst. Sci., 24, 655–672,Short summary
The groundwater regime in cold regions is strongly impacted by the soil freeze–thaw processes and semiarid climatic conditions. In this paper, we incorporate groundwater dynamics in the Noah-MP land surface model to simulate the water exchange between the unsaturated soil zone and an unconfined aquifer in the Prairie Pothole Region. The water table dynamics are reasonably simulated. The water budget of groundwater aquifer under current and future climate are also investigated.
Cornelia Wilske, Axel Suckow, Ulf Mallast, Christiane Meier, Silke Merchel, Broder Merkel, Stefan Pavetich, Tino Rödiger, Georg Rugel, Agnes Sachse, Stephan M. Weise, and Christian Siebert
Hydrol. Earth Syst. Sci., 24, 249–267,Short summary
Despite feeding several million people, the flow system and inter-aquifer communication within one of the major aquifer systems in Israel and the West Bank is still poorly understood. Applying a combination of inorganic elements, anthropogenic organic trace substances and classical environmental age-dating tracers like 3H, CFCs, SF6 and 36Cl / Cl, groundwater flow patterns, mixing end-members, transport times and recharge estimates have been obtained despite very limited data.
Joeri van Engelen, Jarno Verkaik, Jude King, Eman R. Nofal, Marc F. P. Bierkens, and Gualbert H. P. Oude Essink
Hydrol. Earth Syst. Sci., 23, 5175–5198,Short summary
The Nile Delta is an important agricultural area with a fast-growing population, relying increasingly on groundwater. However, saline groundwater extends far land-inward, rendering groundwater close to the coastal zone useless for consumption or agriculture. It normally is assumed that this is caused by mixing due to velocity differences, but here we show that it might also be caused by the coastline being located more land-inward 8000 years ago.
Julian Koch, Helen Berger, Hans Jørgen Henriksen, and Torben Obel Sonnenborg
Hydrol. Earth Syst. Sci., 23, 4603–4619,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.
Donald W. Vasco, Joseph Doetsch, and Ralf Brauchler
Hydrol. Earth Syst. Sci., 23, 4541–4560,Short summary
This paper presents the application of a new approach for calculating the path of a pressure transient in a heterogeneous porous medium containing a slightly compressible fluid. Unlike previous asymptotic approaches, the expressions for the path and travel time are valid in the presence of rapid variations in material properties. The technique is applied to both synthetic transient pressure variations from a test example and actual field data from a field experiment in Widen, Switzerland.
Daniel Erdal and Olaf A. Cirpka
Hydrol. Earth Syst. Sci., 23, 3787–3805,Short summary
Assessing how sensitive uncertain model parameters are to observed data can be done by analyzing an ensemble of model simulations in which the parameters are varied. In subsurface modeling, this involves running heavy models. To reduce time wasted simulating models which show poor behavior, we use a fast polynomial model based on a simple parameter decomposition to approximate the behavior prior to full-model simulation. This largely reduces the cost for the global sensitivity analysis.
Wei Mao, Yan Zhu, Heng Dai, Ming Ye, Jinzhong Yang, and Jingwei Wu
Hydrol. Earth Syst. Sci., 23, 3481–3502,Short summary
A new quasi-3-D model was developed by coupling a soil water balance model with MODFLOW iteratively for regional-scale water flow modeling. The model was tested to be effective and efficient with well-maintained mass balance. A modeling framework was developed to organize the coupling scheme and to handle the pre- and post-processing information. The model is then used to evaluate groundwater recharge in a real-world application, which shows the model practicability in regional-scale problems.
Ning Li, Wolfgang Kinzelbach, Haitao Li, Wenpeng Li, and Fei Chen
Hydrol. Earth Syst. Sci., 23, 2823–2840,Short summary
Groundwater heads within an administrative unit are influenced not only by inside drivers, but also by outside drivers. To assess the efficiency of groundwater management of the administrative unit, we propose the decomposition of groundwater heads within the unit into inside and outside contributions by using three numerical groundwater models. The method is successfully demonstrated using Guantao County, China.
Zhenjiao Jiang, Dirk Mallants, Luk Peeters, Lei Gao, Camilla Soerensen, and Gregoire Mariethoz
Hydrol. Earth Syst. Sci., 23, 2561–2580,Short summary
Paleovalleys often form productive aquifers in the semiarid and arid areas. A methodology based on deep learning is introduced to automatically generate high-resolution 3-D paleovalley maps from low-resolution electrical conductivity data derived from airborne geophysical surveys. It is validated by borehole logs and the surface valley indices that the proposed method in this study provides an effective tool for regional-scale paleovalley mapping and groundwater exploration.
Nicholas D. Woodman, William G. Burgess, Kazi Matin Ahmed, and Anwar Zahid
Hydrol. Earth Syst. Sci., 23, 2461–2479,Short summary
We show that a conventional hydraulic understanding of groundwater level fluctuation is too simplistic for the extensive floodplains of Bangladesh and West Bengal. This is crucial because 150 million people of the region rely on groundwater for drinking and irrigation. We describe a more complex situation: the coupled hydro-mechanical action of surface water coming and going as the seasons change. Our model results will assist sustainable management of groundwater resources across the region.
Quanrong Wang and Hongbin Zhan
Hydrol. Earth Syst. Sci., 23, 2207–2223,Short summary
New multi-species reactive models of the four-phase SWPP test were presented considering the wellbore storages for both groundwater flow and solute transport and a finite-aquifer hydraulic diffusivity, which were ignored in previous studies. The models of the wellbore storage for solute transport were proposed based on the mass balance, and the sensitivity analysis and uniqueness analysis were employed to investigate the assumptions used in previous studies on the parameter estimation.
Wolfgang Dreybrodt and Franci Gabrovšek
Hydrol. Earth Syst. Sci., 23, 1995–2014,Short summary
Numerical models of wormhole formation in fractured porous media provide basic insights on the evolution of complex conduit systems in karst aquifers. In this work we use a time-propagating reactive flow model to explore the evolution of wormholes in a 2-D grid of fractures. We demonstrate physically meaningful mechanisms leading to the formation of individual wormholes and the competition between a set of evolving wormholes.
Ching-Sheng Huang, Ya-Hsin Tsai, Hund-Der Yeh, and Tao Yang
Hydrol. Earth Syst. Sci., 23, 1323–1337,Short summary
The study develops a new model describing head fluctuation induced by oscillatory pumping test (OPT) in an unconfined aquifer with effects of delayed gravity drainage (DGD) and initial condition regarding the hydraulic head prior to OPT. The DGD reduces to instantaneous gravity drainage when a dimensionless parameter exceeds 500. A pseudo-steady-state model excluding initial condition causes a time-shift from the actual transient model in predicting simple harmonic motion of head fluctuation.
Nimrod Inbar, Eliahu Rosenthal, Fabien Magri, Marwan Alraggad, Peter Möller, Akiva Flexer, Joseph Guttman, and Christian Siebert
Hydrol. Earth Syst. Sci., 23, 763–771,Short summary
In areas of enigmatic hydrology, water scarcity, and transboundary water resources, management strategies should rely on comprehensive modeling which must be based on realistic geometry, including all relevant structural features. Based on available geophysical and geological data, a new faulting pattern in the Lower Yarmouk Gorge is suggested as a basis for hydrogeological modeling. Furthermore, unexpected pull-apart basin rim fault evolution is discussed in the context of tectonic collision.
I-Hsien Lee, Chuen-Fa Ni, Fang-Pang Lin, Chi-Ping Lin, and Chien-Chung Ke
Hydrol. Earth Syst. Sci., 23, 19–34,Short summary
Few studies focused on the direct solution of the ADE for 3-D DFNs. The study is the first to solve the ADE and focus on assessing the velocity uncertainty in 3-D DFNs. The velocity uncertainty shows a limited range of influence close to the mean diameter of a fracture. The information is useful for engineering designs at sites with fractured rocks. We quantified that the tracer test in wells might lead to the overestimation of mean concentration and induce high uncertainty in fractured media.
Qiyu Chen, Gregoire Mariethoz, Gang Liu, Alessandro Comunian, and Xiaogang Ma
Hydrol. Earth Syst. Sci., 22, 6547–6566,Short summary
One of the critical issues in MPS simulation is the difficulty in obtaining a credible 3-D training image. We propose an MPS-based 3-D reconstruction method on the basis of 2-D cross sections, making 3-D training images unnecessary. The main advantages of this approach are the high computational efficiency and a relaxation of the stationarity assumption. The results, in comparison with previous MPS methods, show better performance in portraying anisotropy characteristics and in CPU cost.
Rogier Westerhoff, Paul White, and Gonzalo Miguez-Macho
Hydrol. Earth Syst. Sci., 22, 6449–6472,Short summary
Our study improved a global-scale groundwater model to build the first nationwide estimate of the water table surface in New Zealand. By identifying the main alluvial aquifers with high spatial detail, we showed that this model can help better delineate aquifer boundaries. In catchment studies we demonstrated excellent correlation with ground observations and provided water table estimates where data were sparse and across regions, which could help solve trans-boundary issues between catchments.
Yonatan Ganot, Ran Holtzman, Noam Weisbrod, Anat Bernstein, Hagar Siebner, Yoram Katz, and Daniel Kurtzman
Hydrol. Earth Syst. Sci., 22, 6323–6333,Short summary
In recent years, surpluses of desalinated seawater (DSW) are stored in the Israeli coastal aquifer. We monitor DSW spread in the aquifer using the difference between isotope composition of reverse-osmosis DSW and natural fresh water, which simplifies the system to two distinct end-members. A hydrogeological flow and transport model is used to demonstrate the robustness of this simplification, predict the future spread of DSW in the aquifer and mixing in wells, and estimate DSW recovery efficacy.
Claudia Cherubini, Nicola Pastore, Dimitra Rapti, and Concetta I. Giasi
Hydrol. Earth Syst. Sci., 22, 5211–5225,Short summary
The present study investigates the hotspots of groundwater contamination in the industrial area of Modugno (Bari – southern Italy) where the limestone aquifer has a fractured and karstic nature. The characterization of the dynamics of fluid flow and solute transport in fractured aquifers is of broad concern worldwide, especially when considered in relation to water resource exploitation, because fractured aquifers serve as the primary source of drinking water for many areas of the world.
Rena Meyer, Peter Engesgaard, Klaus Hinsby, Jan A. Piotrowski, and Torben O. Sonnenborg
Hydrol. Earth Syst. Sci., 22, 4843–4865,
Khabat Khosravi, Mahdi Panahi, and Dieu Tien Bui
Hydrol. Earth Syst. Sci., 22, 4771–4792,
Yong Xiao, Jingli Shao, Shaun K. Frape, Yali Cui, Xueya Dang, Shengbin Wang, and Yonghong Ji
Hydrol. Earth Syst. Sci., 22, 4381–4400,
Martin Suchy, Leonard I. Wassenaar, Gwyn Graham, and Bernie Zebarth
Hydrol. Earth Syst. Sci., 22, 4267–4279,Short summary
Groundwater contamination by nitrate is a global problem. Understanding sources and transformations of nitrate in aquifers is key to inform remediation, and isotopes of nitrate (15N, 18O) are used for this. Most isotopic investigations are synoptic studies. Here we show that high-frequency nitrate isotope sampling of aquifer recharge better reveals the impact of short-term changes in land use practice or climatic conditions that need to be taken into account when considering long-term trends.
Elliott P. Morrill and Joseph F. Becker
Hydrol. Earth Syst. Sci., 22, 3761–3775,Short summary
The goal of the paper was to develop a method to identify the length and severity of flood events for (re)insurance and risk management usage. We took publically available nationwide discharge data from the USGS to apply our method to. We were able to define a peak and a threshold for each individual site, which served as the basis of our method. The hope was that the method would help replace the current standard hours clause and hopefully improve how flood insurance is covered internationally.
David Pulido-Velazquez, Arianna Renau-Pruñonosa, Carlos Llopis-Albert, Ignacio Morell, Antonio-Juan Collados-Lara, Javier Senent-Aparicio, and Leticia Baena-Ruiz
Hydrol. Earth Syst. Sci., 22, 3053–3074,Short summary
We have developed a method to assess hydrological impacts of future potential global change (GC) scenarios in a coastal aquifer, the Plana Oropesa-Torreblanca aquifer. Quantity and quality issues are simultaneously considered. It includes the generation of potential GC scenarios involving different sources of uncertainty and an integrated modelling framework to assess their impacts. It is a valuable tool to improve our aquifer knowledge and to help in the analysis of management strategies.
Martina Siena and Monica Riva
Hydrol. Earth Syst. Sci., 22, 2971–2985,Short summary
The development of sustainable strategies for groundwater resources exploitation in coastal regions is subordinated to the characterization of seawater intrusion (SWI) phenomena. We develop a numerical model tailored to a real coastal aquifer to investigate quantitatively the joint effects of hydraulic properties heterogeneity and pumping configuration on saltwater inland penetration and saltwater–freshwater mixing. Our results allowed identifying efficient scenarios for the reduction of SWI.
Katherine M. Ransom, Andrew M. Bell, Quinn E. Barber, George Kourakos, and Thomas Harter
Hydrol. Earth Syst. Sci., 22, 2739–2758,Short summary
We estimated a probability distribution of nitrogen loading rates for crop and land-use groups from regional groundwater data. Water & natural land use had the lowest estimated rates, while dairy land use had the highest. Most results compare favorably to previous estimates, though mass balance estimates for several crop groups were higher than our model estimates. The information can provide a better assessment of land-use impacts to water quality absent information on farm nutrient management.
Sebastian Huizer, Max Radermacher, Sierd de Vries, Gualbert H. P. Oude Essink, and Marc F. P. Bierkens
Hydrol. Earth Syst. Sci., 22, 1065–1080,Short summary
For a large beach nourishment called the Sand Engine we have examined the impact of groundwater recharge, tides, storm surges, and geomorphological changes on the growth of the fresh groundwater resources between 2011 and 2016. With detailed model simulations of these coastal processes we were able to get a good match with field measurements, and demonstrated the importance of wave runup and coastal erosion in studies on fresh groundwater in such dynamic coastal environments.
Akata, N., Kakiuchi, H., Shima, H., Iyogi, T., Momoshima, N., and Hisamutsu, S.: Tritium concentrations in the atmospheric environment at Rokkasho, Japan before the final testing of the spent nuclear fuel reprocessing plant, J. Environ. Radioact., 102, 837–842, https://doi.org/10.1016/j.jenvrad.2011.05.005, 2011.
Cartwright, I. and Morgenstern, U.: Transit times from rainfall to baseflow in headwater catchments estimated using tritium: the Ovens River, Australia, Hydrol. Earth Syst. Sci., 19, 3771–3785, https://doi.org/10.5194/hess-19-3771-2015, 2015.
Dim, J. R., Sakura, Y., Fukami, H., and Miyakoshi, A.: Spatial characteristics of groundwater temperature in the Ishikari Lowland, Hokkaido, northern Japan: analytical and numerical applications, Hydrogeol. J., 10, 296–306, 2002.
Duvert, C., Stewart, M. K., Cendón, D. I., and Raiber, M.: Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream, Hydrol. Earth Syst. Sci., 20, 257–277, https://doi.org/10.5194/hess-20-257-2016, 2016.
Geological Survey of Japan (AIST) (ed.): Seamless digital geological map of Japan 1: 200,000, 3 July 2012 version, Research Information Database DB084, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, available at: https://gbank.gsj.jp/geonavi/geonavi.php (last access: 10 April 2016), 2012.
Gleeson, T., Befus, K., Jasechko, S., Luijendijk, E., and Cardenas, M. B.: The global volume and distribution of modern groundwater. Nature Geoscience, 9, 161–168, 2016.
Grannemann, N. G., Hunt, R. J., Nicholas, J. R., Reilly, T. E., and Winter, T. C.: The Importance of Ground Water in the Great Lakes Region, Water-Resources Investigations Report 00–4008, US Geological Survey, Lansing, Michigan, 19 pp., 2000.
Gusyev, M. A. and Haitjema, H. M: Modeling flow in wetlands and underlying aquifers using a discharge potential formulation, J. Hydrol., 408, 91–99, https://doi.org/10.1016/j.jhydrol.2011.07.026, 2011.
Gusyev, M. A., Haitjema, H. M., Carlson, C. P., and Gonzalez, M. A.: Use of nested flow models and interpolation techniques for science-base management of the Sheyenne National Grassland, North Dakota, USA, Groundwater, 51, 414–420, https://doi.org/10.1111/j.1745-6584.2012.00989.x, 2012.
Gusyev, M. A., Toews, M., Morgenstern, U., Stewart, M., White, P., Daughney, C., and Hadfield, J.: Calibration of a transient transport model to tritium data in streams and simulation of groundwater ages in the western Lake Taupo catchment, New Zealand, Hydrol. Earth Syst. Sci., 17, 1217–1227, https://doi.org/10.5194/hess-17-1217-2013, 2013.
Gusyev, M. A., Abrams, D., Toews, M., Morgenstern, U., and Stewart, M. K.: A comparison of particle-tracking and solute transport methods for simulation of tritium concentrations and groundwater transit times in river water, Hydrol. Earth Syst. Sci., 18, 3109–3119, https://doi.org/10.5194/hess-18-3109-2014, 2014.
Gusyev, M. A., Kwak Y., Khairul, I., Arifuzzaman, B., Sawano H., Magome, J. and Takeuchi, K.: Effectiveness of water infrastructure for river flood management: Part 1 – Flood Hazard Assessment using hydrological models in Bangladesh, Proc. IAHS 2015, 370, 75–81, https://doi.org/10.5194/piahs-370-75-2015, 2015.
Gusyev, M. A., Gädeke, A., Magome, J., Sugiura, A., Cullmann, J., Sawano, H., and Takeuchi, K.: Connecting global and local scale flood risk assessment: A case study of the Rhine River basin flood hazard. J. Flood Risk Manage., in press, https://doi.org/10.1111/jfr3.12243, 2016.
Harms, P. A., Visser, A., Moran, J. E., and Esseret, K. B.: Distribution of tritium in precipitation and surface water in California, J. Hydrol., 534, 63–72, 2016.
Hasegawa, H., Sawagaki, T., Takashima, R., Yamamoto, M., and Irino, T.: Geology and Geomorphology along the Ishikari River in central Hokkaido, Post Symposium Field Trip Guidebook, 2nd annual symposium of International Geoscience Programme (IGCP), 13–14 June, 2011.
Ikeda, M., Takata, S., and Matsueda, H.: Estimated Values of the Environmental Tritium Concentration and the Altitude Isotope Effects of δD and δO18 in Hokkaido, Radioisotopes, 47, 812–823, 1998.
International Atomic Energy Agency (IAEA)/World Meteorological Organization (WMO): Global Network of Isotopes in Precipitation. The GNIP Database, IAEA, available at: http://www.iaea.org/water, last access: August 2014.
Iwata Y., Hirota, T., Hayashi M., Suzuki S., and Hasegawa, S.: Effects of frozen soil and snow cover on cold-season soil water dynamics in Tokachi, Japan, Hydrol. Process., 24, 1755–1765, https://doi.org/10.1002/hyp.7621, 2010.
Japan Chemical Analysis Center (JCAC): Tritium in precipitation data, available at: http://search.kankyo-hoshano.go.jp/servlet/search.top, last access: July 2015.
Japan Meteorological Agency (JMA): Meteorological data of Japan, http://www.jma.go.jp/jma/menu/menureport.html, last access: February 2016.
Jasechko, S., Kirchner, J. W., Welker, J. M., and McDonnell, J. J.: Substantial proportion of global streamflow less than three months old, Nature Geosci., 9, 126–129, 2016.
Jurgens, B. C., Böhlke, J. K., and Eberts, S. M.: TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data. US Geological Survey Techniques and Methods Report 4-F3, 60 p., 2012.
Kirchner, J. W.: Aggregation in environmental systems – Part 1: Seasonal tracer cycles quantify young water fractions, but not mean transit times, in spatially heterogeneous catchments, Hydrol. Earth Syst. Sci., 20, 279–297, https://doi.org/10.5194/hess-20-279-2016, 2016a.
Kirchner, J. W.: Aggregation in environmental systems – Part 2: Catchment mean transit times and young water fractions under hydrologic nonstationarity, Hydrol. Earth Syst. Sci., 20, 299–328, https://doi.org/10.5194/hess-20-299-2016, 2016b.
Leopoldo, P. R., Martinez, J. C. and Mortatti, J.: Estimation using 18O of the water residence time of small watersheds. In: Proceedings of an International Symposium on Isotope Techniques in Water Resources Development. International Atomic Energy Agency, Vienna, IAEA-SM-319/4, 75–84, 1992.
Magome, J., Gusyev, M. A., Hasegawa, A., and Takeuchi, K.: River discharge simulation of a distributed hydrological model on global scale for the hazard quantification, edited by: Weber, T., McPhee, M. J. and Anderssen, R. S., MODSIM2015, 21st International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand, 1593–1599, 2015.
Małoszewski, P. and Zuber, A.: Determining the turnover time of groundwater systems with the aid of environmental tracers 1. Models and their applicability, J. Hydrol., 57, 207–231, https://doi.org/10.1016/0022-1694(82)90147-0, 1982.
Małoszewski, P., Rauert, W., Trimborn, P., Herrmann, A., and Rau, R.: Isotope hydrological study of mean transit times in an alpine basin (Wimbechtal, Germany), J. Hydrol., 140, 343–360, 1992.
Matsumoto, T., Maruoka, T., Shimoda, G., Obata, H., Kagi, H., Suzuku, K., Yamamoto, k., Mitsugushi, T., Hagino, K., Tomioka, N., Sambandan, C., Brummer, D., Klaus, P., and Aggarwal, P.: Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident, Sci. Total Environ., 445–446, 365–370, 2013.
McGuire, K. J. and McDonnell, J. J.: A review and evaluation of catchment transit time modeling. J. Hydrol., 330, 543–563, 2006.
McGuire, K. J., DeWalle, D. R., and Gburek, W. J.: Evaluation of mean residence time in subsurface waters using oxygen-18 fluctuations during drought conditions in mid-Appalachians, J. Hydrol., 261, 132–149, 2002.
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.
Michel, R. L.: Tritium hydrology of the Mississippi River Basin, Hydrol. Process., 18, 1255–1269, 2004.
Michel, R. L., Aggarwal, P., Luis Araguas-Araguas, L., Kurttas, T., Newman, B. D., and Vitvar, T.: A simplified approach to analysing historical and recent tritium data in surface waters, Hydrol. Process., 29, 572–578, 2015.
Morgenstern, U. and Taylor, C. B.: Ultra Low-level tritium measurement using electrolytic enrichment and LSC, Isotopes Environ. Health Stud., 45, 96–117, https://doi.org/10.1080/10256010902931194, 2009.
Morgenstern, U., Stewart, M. K., and Stenger, K.: Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow, Hydrol. Earth Syst. Sci., 14, 2289–2301, https://doi.org/10.5194/hess-14-2289-2010, 2010.
Morgenstern, U., Daughney, C. J., Leonard, G., Gordon, D., Donath, F. M., and Reeves, R.: Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand, Hydrol. Earth Syst. Sci., 19, 803–822, https://doi.org/10.5194/hess-19-803-2015, 2015.
Navarathinam, K., M. Gusyev, A. Hasegawa, Magome, J., and Takeuchi, K.: Agricultural flood and drought risk reduction by a proposed multi-purpose dam: A case study of the Malwathoya River Basin, Sri Lanka, edited by: Weber, T., McPhee, M. J. and Anderssen, R. S., MODSIM2015, 21st International Congress on Modelling and Simulation, Modelling and Simulation Society of Australia and New Zealand, 1600–1606, 2015.
Nawai, J., Gusyev, M., Hasegawa, A., and Takeuchi, K.: Flood and drought assessment with dam infrastructure: A case study of the Ba River basin, Fiji, in: MODSIM2015, 21st International Congress on Modelling and Simulation, edited by: Weber, T., McPhee, M. J., and Anderssen, R. S., Modelling and Simulation Society of Australia and New Zealand, December 2015, 1607–1613, 2015.
Sakata, Y. and Ikeda, R.: Regional Mapping of Vertical Hydraulic Gradient Using Uncertain Well Data: A Case Study of the Toyohira River Alluvial Fan, Japan, J. Water Resour. Protect., 5, 823–834, 2013.
Stewart, M. K., Mehlhorn, J., and Elliott, S.: Hydrometric and natural tracer (18O, silica, 3H and SF6) evidence for a dominant groundwater contribution to Pukemanga Stream, New Zealand, Hydrol Process., 21, 3340–3356, https://doi.org/10.1002/hyp.6557, 2007.
Stewart, M. K., Morgenstern, U., and McDonnell, J. J.: Truncation of stream residence time: how the use of stable isotopes has skewed our concept of streamwater age and origin, Hydrol. Process., 24, 1646–1659, 2010.
Stewart, M. K., Morgenstern, U., McDonnell, J. J., and Pfister, L.: The “hidden streamflow” challenge in catchment hydrology: a call to action for stream water transit time analysis, invited Commentary, Hydrol. Process., 26, 2061–2066, https://doi.org/10.1002/hyp.9262, 2012.
Stewart, M. K.: Promising new baseflow separation and recession analysis methods applied to streamflow at Glendhu Catchment, New Zealand, Hydrol. Earth Syst. Sci., 19, 2587–2603, https://doi.org/10.5194/hess-19-2587-2015, 2015.
Stewart, M. K. and Morgenstern, U.: Importance of tritium-based transit times in hydrological systems. Wiley Interdisciplinary Reviews: Water, 3, 145–154, https://doi.org/10.1002/wat2.1134, 2016.
Tadros, C. V., Hughes, C. E., Crawford, J., Hollins, S. E., and Chisari, R.: Tritium in Australian precipitation: A 50 year record, J. Hydrol., 513, 262–273, 2014.
Takahashi, T., Nishida, M., Ohno, S., and Hamada, T.: Tritium concentration in wine, rain and ground water, Radioisotopes, 18, 32–35, 1969.
Takeuchi, K., Hapuarachchi, P., Zhou, M., Ishidaira, H., and Magome J.: A BTOP model to extend TOPMODEL for distributed hydrological simulation of large basins, Hydrol. Process., 22, 3236–3251, 2008.
Tanaka, T.: Groundwater governance in Asia: present state and barriers to implementation of good governance, Proc. IAHS, 364, 470–474, https://doi.org/10.5194/piahs-364-470-2014, 2014.
Water Information System (WIS): Ministry of Land, Infrastructure, Transport and Tourism (MLIT) database, http://www1.river.go.jp/, last access: February 2016.
Tritium-estimated groundwater mean transit times (MTTs) and storage volumes provide useful information for water resources management especially during droughts. In Hokkaido, we find that (1) one tritium measurement at baseflow is already sufficient to estimate MTT for some catchments, (2) the hydrogeological settings control tritium transit times of subsurface groundwater storage at baseflow, and (3) in future, one tritium measurement will be sufficient to estimate MTT in most Japanese catchments.
Tritium-estimated groundwater mean transit times (MTTs) and storage volumes provide useful...