Articles | Volume 22, issue 7 
            
                
                    
            
            
            https://doi.org/10.5194/hess-22-3639-2018
                    © 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-22-3639-2018
                    © Author(s) 2018. This work is distributed under 
the Creative Commons Attribution 4.0 License.
                the Creative Commons Attribution 4.0 License.
Ecohydrological particle model based on representative domains
                                            Karlsruhe Institute of Technology KIT, Institute of Water Resources and River Basin Management, Chair of Hydrology, Kaiserstr. 12, 76131 Karlsruhe, Germany
                                        
                                    Erwin Zehe
                                            Karlsruhe Institute of Technology KIT, Institute of Water Resources and River Basin Management, Chair of Hydrology, Kaiserstr. 12, 76131 Karlsruhe, Germany
                                        
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Tobias Karl David Weber, Lutz Weihermüller, Attila Nemes, Michel Bechtold, Aurore Degré, Efstathios Diamantopoulos, Simone Fatichi, Vilim Filipović, Surya Gupta, Tobias L. Hohenbrink, Daniel R. Hirmas, Conrad Jackisch, Quirijn de Jong van Lier, John Koestel, Peter Lehmann, Toby R. Marthews, Budiman Minasny, Holger Pagel, Martine van der Ploeg, Shahab Aldin Shojaeezadeh, Simon Fiil Svane, Brigitta Szabó, Harry Vereecken, Anne Verhoef, Michael Young, Yijian Zeng, Yonggen Zhang, and Sara Bonetti
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                                                Pedotransfer functions (PTFs) are used to predict parameters of models describing the hydraulic properties of soils. The appropriateness of these predictions critically relies on the nature of the datasets for training the PTFs and the physical comprehensiveness of the models. This roadmap paper is addressed to PTF developers and users and critically reflects the utility and future of PTFs. To this end, we present a manifesto aiming at a paradigm shift in PTF research.
                                            
                                            
                                        Tobias L. Hohenbrink, Conrad Jackisch, Wolfgang Durner, Kai Germer, Sascha C. Iden, Janis Kreiselmeier, Frederic Leuther, Johanna C. Metzger, Mahyar Naseri, and Andre Peters
                                    Earth Syst. Sci. Data, 15, 4417–4432, https://doi.org/10.5194/essd-15-4417-2023, https://doi.org/10.5194/essd-15-4417-2023, 2023
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                                                The article describes a collection of 572 data sets of soil water retention and unsaturated hydraulic conductivity data measured with state-of-the-art laboratory methods. Furthermore, the data collection contains basic soil properties such as soil texture and organic carbon content. We expect that the data will be useful for various important purposes, for example, the development of soil hydraulic property models and related pedotransfer functions.
                                            
                                            
                                        Conrad Jackisch, Sibylle K. Hassler, Tobias L. Hohenbrink, Theresa Blume, Hjalmar Laudon, Hilary McMillan, Patricia Saco, and Loes van Schaik
                                    Hydrol. Earth Syst. Sci., 25, 5277–5285, https://doi.org/10.5194/hess-25-5277-2021, https://doi.org/10.5194/hess-25-5277-2021, 2021
                            Conrad Jackisch, Samuel Knoblauch, Theresa Blume, Erwin Zehe, and Sibylle K. Hassler
                                    Biogeosciences, 17, 5787–5808, https://doi.org/10.5194/bg-17-5787-2020, https://doi.org/10.5194/bg-17-5787-2020, 2020
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                                                We developed software to calculate the root water uptake (RWU) of beech tree roots from soil moisture dynamics. We present our approach and compare RWU to measured sap flow in the tree stem. The study relates to two sites that are similar in topography and weather but with contrasting soils. While sap flow is very similar between the two sites, the RWU is different. This suggests that soil characteristics have substantial influence. Our easy-to-implement RWU estimate may help further studies.
                                            
                                            
                                        Conrad Jackisch, Kai Germer, Thomas Graeff, Ines Andrä, Katrin Schulz, Marcus Schiedung, Jaqueline Haller-Jans, Jonas Schneider, Julia Jaquemotte, Philipp Helmer, Leander Lotz, Andreas Bauer, Irene Hahn, Martin Šanda, Monika Kumpan, Johann Dorner, Gerrit de Rooij, Stefan Wessel-Bothe, Lorenz Kottmann, Siegfried Schittenhelm, and Wolfgang Durner
                                    Earth Syst. Sci. Data, 12, 683–697, https://doi.org/10.5194/essd-12-683-2020, https://doi.org/10.5194/essd-12-683-2020, 2020
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                                                Soil water content and matric potential are central hydrological state variables. A large variety of automated probes and sensor systems for field monitoring exist. In a field experiment under idealised conditions we compared 15 systems for soil moisture and 14 systems for matric potential. The individual records of one system agree well with the others. Most records are also plausible. However, the absolute values of the different measuring systems span a very large range of possible truths.
                                            
                                            
                                        Ralf Loritz, Axel Kleidon, Conrad Jackisch, Martijn Westhoff, Uwe Ehret, Hoshin Gupta, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 23, 3807–3821, https://doi.org/10.5194/hess-23-3807-2019, https://doi.org/10.5194/hess-23-3807-2019, 2019
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                                                In this study, we develop a topographic index explaining hydrological similarity within a energy-centered framework, with the observation that the majority of potential energy is dissipated when rainfall becomes runoff.
                                            
                                            
                                        Erwin Zehe, Ralf Loritz, Conrad Jackisch, Martijn Westhoff, Axel Kleidon, Theresa Blume, Sibylle K. Hassler, and Hubert H. Savenije
                                    Hydrol. Earth Syst. Sci., 23, 971–987, https://doi.org/10.5194/hess-23-971-2019, https://doi.org/10.5194/hess-23-971-2019, 2019
                            Ralf Loritz, Hoshin Gupta, Conrad Jackisch, Martijn Westhoff, Axel Kleidon, Uwe Ehret, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 22, 3663–3684, https://doi.org/10.5194/hess-22-3663-2018, https://doi.org/10.5194/hess-22-3663-2018, 2018
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                                                In this study we explore the role of spatially distributed information on hydrological modeling. For that, we develop and test an approach which draws upon information theory and thermodynamic reasoning. We show that the proposed set of methods provide a powerful framework for understanding and diagnosing how and when process organization and functional similarity of hydrological systems emerge in time and, hence, when which landscape characteristic is important in a model application.
                                            
                                            
                                        Lisa Angermann, Conrad Jackisch, Niklas Allroggen, Matthias Sprenger, Erwin Zehe, Jens Tronicke, Markus Weiler, and Theresa Blume
                                    Hydrol. Earth Syst. Sci., 21, 3727–3748, https://doi.org/10.5194/hess-21-3727-2017, https://doi.org/10.5194/hess-21-3727-2017, 2017
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                                                This study investigates the temporal dynamics and response velocities of lateral preferential flow at the hillslope. The results are compared to catchment response behavior to infer the large-scale implications of the observed processes. A large portion of mobile water flows through preferential flow paths in the structured soils, causing an immediate discharge response. The study presents a methodological approach to cover the spatial and temporal domain of these highly heterogeneous processes.
                                            
                                            
                                        Conrad Jackisch, Lisa Angermann, Niklas Allroggen, Matthias Sprenger, Theresa Blume, Jens Tronicke, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 3749–3775, https://doi.org/10.5194/hess-21-3749-2017, https://doi.org/10.5194/hess-21-3749-2017, 2017
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                                                Rapid subsurface flow in structured soils facilitates fast vertical and lateral redistribution of event water. We present its in situ exploration through local measurements and irrigation experiments. Special emphasis is given to a coherent combination of hydrological and geophysical methods. The study highlights that form and function operate as conjugated pairs. Dynamic imaging through time-lapse GPR was key to observing both and to identifying hydrologically relevant structures.
                                            
                                            
                                        Simon Paul Seibert, Conrad Jackisch, Uwe Ehret, Laurent Pfister, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 2817–2841, https://doi.org/10.5194/hess-21-2817-2017, https://doi.org/10.5194/hess-21-2817-2017, 2017
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                                                Runoff production mechanisms and their corresponding physiographic controls continue to pose major research challenges in catchment hydrology. We propose innovative data-driven diagnostic signatures for overcoming the prevailing status quo in inter-comparison studies. Specifically, we present dimensionless double mass curves which allow us to infer information on runoff generation at the seasonal and annual timescales. The method is based on commonly available data.
                                            
                                            
                                        Ralf Loritz, Sibylle K. Hassler, Conrad Jackisch, Niklas Allroggen, Loes van Schaik, Jan Wienhöfer, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 1225–1249, https://doi.org/10.5194/hess-21-1225-2017, https://doi.org/10.5194/hess-21-1225-2017, 2017
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                                                In this study we examine whether we can step beyond the qualitative character of perceptual models by using them as a blueprint for setting up representative hillslope models. Thereby we test the hypothesis of whether a single hillslope can represent the functioning of an entire lower mesoscale catchment in a spatially aggregated way.
                                            
                                            
                                        Benjamin Müller, Matthias Bernhardt, Conrad Jackisch, and Karsten Schulz
                                    Hydrol. Earth Syst. Sci., 20, 3765–3775, https://doi.org/10.5194/hess-20-3765-2016, https://doi.org/10.5194/hess-20-3765-2016, 2016
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                                                A technology for the spatial derivation of soil texture classes is presented. Information about soil texture is key for predicting the local and regional hydrological cycle. It is needed for the calculation of soil water movement, the share of surface runoff, the evapotranspiration rate and others. Nevertheless, the derivation of soil texture classes is expensive and time-consuming. The presented technique uses soil samples and remotely sensed data for estimating their spatial distribution.
                                            
                                            
                                        Erwin Zehe and Conrad Jackisch
                                    Hydrol. Earth Syst. Sci., 20, 3511–3526, https://doi.org/10.5194/hess-20-3511-2016, https://doi.org/10.5194/hess-20-3511-2016, 2016
                            E. Zehe, U. Ehret, L. Pfister, T. Blume, B. Schröder, M. Westhoff, C. Jackisch, S. J. Schymanski, M. Weiler, K. Schulz, N. Allroggen, J. Tronicke, L. van Schaik, P. Dietrich, U. Scherer, J. Eccard, V. Wulfmeyer, and A. Kleidon
                                    Hydrol. Earth Syst. Sci., 18, 4635–4655, https://doi.org/10.5194/hess-18-4635-2014, https://doi.org/10.5194/hess-18-4635-2014, 2014
                            Dan Elhanati, Erwin Zehe, Ishai Dror, and Brian Berkowitz
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-3365, https://doi.org/10.5194/egusphere-2025-3365, 2025
                                    This preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS). 
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                                                Measurements of water isotopes are often used to estimate water transit time distributions and aquifer storage thickness in catchments. However, laboratory-scale measurements show that water isotopes exhibit transport behavior identical to that of inert chemical tracers rather than of pure water. The measured mean tracer and apparent mean water velocities are not necessarily equal; recognition of this inequality is critical when estimating catchment properties such as aquifer storage thickness.
                                            
                                            
                                        Karl Nicolaus van Zweel, Laurent Gourdol, Jean François Iffly, Loïc Léonard, François Barnich, Laurent Pfister, Erwin Zehe, and Christophe Hissler
                                    Earth Syst. Sci. Data, 17, 2217–2229, https://doi.org/10.5194/essd-17-2217-2025, https://doi.org/10.5194/essd-17-2217-2025, 2025
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                                                Our study monitored groundwater in a Luxembourg forest over a year to understand water and chemical changes. We found seasonal variations in water chemistry, influenced by rainfall and soil interactions. These data help predict environmental responses and manage water resources better. By measuring key parameters like pH and dissolved oxygen, our research provides valuable insights into groundwater behaviour and serves as a resource for future environmental studies.
                                            
                                            
                                        Svenja Hoffmeister, Sibylle Kathrin Hassler, Friederike Lang, Rebekka Maier, Betserai Isaac Nyoka, and Erwin Zehe
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-1719, https://doi.org/10.5194/egusphere-2025-1719, 2025
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                                                Combining trees and crops in agroforestry systems can potentially be a sustainable option for agriculture facing climate change impacts. We used methods from soil science and hydrology to assess the effect of adding gliricidia trees to maize fields, on carbon content, soil properties and water availability. Our results show a clear increase in carbon contents and effects on physical soil characteristics and water uptake and retention as a consequence of the agroforestry treatment.
                                            
                                            
                                        Evgeny Shavelzon, Erwin Zehe, and Yaniv Edery
                                        EGUsphere, https://doi.org/10.22541/essoar.173687429.91307309/v1, https://doi.org/10.22541/essoar.173687429.91307309/v1, 2025
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                                                We analyze how chemical reactions and fluid movement interact in porous materials, focusing on how water paths form in underground environments. Using a thermodynamic approach, we track energy dissipation and entropy changes to understand this process. Over time, water channels become more defined, reducing chemical mixing and energy loss. Eventually, the system stabilizes, with flow concentrated in efficient pathways, minimizing further reactions and energy use.
                                            
                                            
                                        Ashish Manoj J, Ralf Loritz, Hoshin Gupta, and Erwin Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2024-375, https://doi.org/10.5194/hess-2024-375, 2024
                                    Revised manuscript under review for HESS 
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                                                Traditional hydrological models typically operate in a forward mode, simulating streamflow and other catchment fluxes based on precipitation input. In this study, we explored the possibility of reversing this process—inferring precipitation from streamflow data—to improve flood event modelling. We then used the generated precipitation series to run hydrological models, resulting in more accurate estimates of streamflow and soil moisture.
                                            
                                            
                                        Svenja Hoffmeister, Rafael Bohn Reckziegel, Ben du Toit, Sibylle K. Hassler, Florian Kestel, Rebekka Maier, Jonathan P. Sheppard, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 28, 3963–3982, https://doi.org/10.5194/hess-28-3963-2024, https://doi.org/10.5194/hess-28-3963-2024, 2024
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                                                We studied a tree–crop ecosystem consisting of a blackberry field and an alder windbreak. In the water-scarce region, irrigation provides sufficient water for plant growth. The windbreak lowers the irrigation amount by reducing wind speed and therefore water transport into the atmosphere. These ecosystems could provide sustainable use of water-scarce landscapes, and we studied the complex interactions by observing several aspects (e.g. soil, nutrients, carbon assimilation, water).
                                            
                                            
                                        Tobias Karl David Weber, Lutz Weihermüller, Attila Nemes, Michel Bechtold, Aurore Degré, Efstathios Diamantopoulos, Simone Fatichi, Vilim Filipović, Surya Gupta, Tobias L. Hohenbrink, Daniel R. Hirmas, Conrad Jackisch, Quirijn de Jong van Lier, John Koestel, Peter Lehmann, Toby R. Marthews, Budiman Minasny, Holger Pagel, Martine van der Ploeg, Shahab Aldin Shojaeezadeh, Simon Fiil Svane, Brigitta Szabó, Harry Vereecken, Anne Verhoef, Michael Young, Yijian Zeng, Yonggen Zhang, and Sara Bonetti
                                    Hydrol. Earth Syst. Sci., 28, 3391–3433, https://doi.org/10.5194/hess-28-3391-2024, https://doi.org/10.5194/hess-28-3391-2024, 2024
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                                                Pedotransfer functions (PTFs) are used to predict parameters of models describing the hydraulic properties of soils. The appropriateness of these predictions critically relies on the nature of the datasets for training the PTFs and the physical comprehensiveness of the models. This roadmap paper is addressed to PTF developers and users and critically reflects the utility and future of PTFs. To this end, we present a manifesto aiming at a paradigm shift in PTF research.
                                            
                                            
                                        Tobias L. Hohenbrink, Conrad Jackisch, Wolfgang Durner, Kai Germer, Sascha C. Iden, Janis Kreiselmeier, Frederic Leuther, Johanna C. Metzger, Mahyar Naseri, and Andre Peters
                                    Earth Syst. Sci. Data, 15, 4417–4432, https://doi.org/10.5194/essd-15-4417-2023, https://doi.org/10.5194/essd-15-4417-2023, 2023
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                                                The article describes a collection of 572 data sets of soil water retention and unsaturated hydraulic conductivity data measured with state-of-the-art laboratory methods. Furthermore, the data collection contains basic soil properties such as soil texture and organic carbon content. We expect that the data will be useful for various important purposes, for example, the development of soil hydraulic property models and related pedotransfer functions.
                                            
                                            
                                        Samuel Schroers, Ulrike Scherer, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 27, 2535–2557, https://doi.org/10.5194/hess-27-2535-2023, https://doi.org/10.5194/hess-27-2535-2023, 2023
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                                                The hydrological cycle shapes our landscape. With an accelerating change of the world's climate and hydrological dynamics, concepts of evolution of natural systems become more important. In this study, we elaborated a thermodynamic framework for runoff and sediment transport and show from model results as well as from measurements during extreme events that the developed concept is useful for understanding the evolution of the system's mass, energy, and entropy fluxes.
                                            
                                            
                                        Judith Meyer, Malte Neuper, Luca Mathias, Erwin Zehe, and Laurent Pfister
                                    Hydrol. Earth Syst. Sci., 26, 6163–6183, https://doi.org/10.5194/hess-26-6163-2022, https://doi.org/10.5194/hess-26-6163-2022, 2022
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                                                We identified and analysed the major atmospheric components of rain-intense thunderstorms that can eventually lead to flash floods: high atmospheric moisture, sufficient latent instability, and weak thunderstorm cell motion. Between 1981 and 2020, atmospheric conditions became likelier to support strong thunderstorms. However, the occurrence of extreme rainfall events as well as their rainfall intensity remained mostly unchanged.
                                            
                                            
                                        Ralf Loritz, Maoya Bassiouni, Anke Hildebrandt, Sibylle K. Hassler, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 26, 4757–4771, https://doi.org/10.5194/hess-26-4757-2022, https://doi.org/10.5194/hess-26-4757-2022, 2022
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                                                In this study, we combine a deep-learning approach that predicts sap flow with a hydrological model to improve soil moisture and transpiration estimates at the catchment scale. Our results highlight that hybrid-model approaches, combining machine learning with physically based models, are a promising way to improve our ability to make hydrological predictions.
                                            
                                            
                                        Samuel Schroers, Olivier Eiff, Axel Kleidon, Ulrike Scherer, Jan Wienhöfer, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 26, 3125–3150, https://doi.org/10.5194/hess-26-3125-2022, https://doi.org/10.5194/hess-26-3125-2022, 2022
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                                                In hydrology the formation of landform patterns is of special interest as changing forcings of the natural systems, such as climate or land use, will change these structures. In our study we developed a thermodynamic framework for surface runoff on hillslopes and highlight the differences of energy conversion patterns on two related spatial and temporal scales. The results indicate that surface runoff on hillslopes approaches a maximum power state.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Brian Berkowitz, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 26, 1615–1629, https://doi.org/10.5194/hess-26-1615-2022, https://doi.org/10.5194/hess-26-1615-2022, 2022
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                                                We present a (physically based) Lagrangian approach to simulate diffusive mixing processes on the pore scale beyond perfectly mixed conditions. Results show the feasibility of the approach for reproducing measured mixing times and concentrations of isotopes over pore sizes and that typical shapes of breakthrough curves (normally associated with non-uniform transport in heterogeneous soils) may also occur as a result of imperfect subscale mixing in a macroscopically homogeneous soil matrix.
                                            
                                            
                                        Erwin Zehe, Ralf Loritz, Yaniv Edery, and Brian Berkowitz
                                    Hydrol. Earth Syst. Sci., 25, 5337–5353, https://doi.org/10.5194/hess-25-5337-2021, https://doi.org/10.5194/hess-25-5337-2021, 2021
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                                                This study uses the concepts of entropy and work to quantify and explain the emergence of preferential flow and transport in heterogeneous saturated porous media. We found that the downstream concentration of solutes in preferential pathways implies a downstream declining entropy in the transverse distribution of solute transport pathways. Preferential flow patterns with lower entropies emerged within media of higher heterogeneity – a stronger self-organization despite a higher randomness.
                                            
                                            
                                        Conrad Jackisch, Sibylle K. Hassler, Tobias L. Hohenbrink, Theresa Blume, Hjalmar Laudon, Hilary McMillan, Patricia Saco, and Loes van Schaik
                                    Hydrol. Earth Syst. Sci., 25, 5277–5285, https://doi.org/10.5194/hess-25-5277-2021, https://doi.org/10.5194/hess-25-5277-2021, 2021
                            Jan Bondy, Jan Wienhöfer, Laurent Pfister, and Erwin Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2021-174, https://doi.org/10.5194/hess-2021-174, 2021
                                    Manuscript not accepted for further review 
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                                                The Budyko curve is a widely-used and simple framework to predict the mean water balance of river catchments. While many catchments are in close accordance with the Budyko curve, others show more or less significant deviations. Our study aims at better understanding the role of soil storage characteristics in the mean water balance and offsets from the Budyko curve. Soil storage proved to be a very sensitive property and potentially explains significant deviations from the curve.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Julian Klaus, Brian Berkowitz, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 25, 1483–1508, https://doi.org/10.5194/hess-25-1483-2021, https://doi.org/10.5194/hess-25-1483-2021, 2021
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                                                The key innovation of the study is a method to simulate reactive solute transport in the vadose zone within a Lagrangian framework. We extend the LAST-Model with a method to account for non-linear sorption and first-order degradation processes during unsaturated transport of reactive substances in the matrix and macropores. Model evaluations using bromide and pesticide data from irrigation experiments under different flow conditions on various timescales show the feasibility of the method.
                                            
                                            
                                        Samuel Schroers, Olivier Eiff, Axel Kleidon, Jan Wienhöfer, and Erwin Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2021-79, https://doi.org/10.5194/hess-2021-79, 2021
                                    Manuscript not accepted for further review 
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                                                In this study we ask the basic question why surface runoff forms drainage networks and confluences at all and how structural macro form and micro topography is a result of thermodynamic laws. We find that on a macro level hillslopes should tend from negative exponential towards exponential forms and that on a micro level the formation of rills goes hand in hand with drainage network formation of river basins. We hypothesize that we can learn more about erosion processes if we extend this theory.
                                            
                                            
                                        Nicolas Björn Rodriguez, Laurent Pfister, Erwin Zehe, and Julian Klaus
                                    Hydrol. Earth Syst. Sci., 25, 401–428, https://doi.org/10.5194/hess-25-401-2021, https://doi.org/10.5194/hess-25-401-2021, 2021
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                                                Different parts of water have often been used as tracers to determine the age of water in streams. The stable tracers, such as deuterium, are thought to be unable to reveal old water compared to the radioactive tracer called tritium. We used both tracers, measured in precipitation and in a stream in Luxembourg, to show that this is not necessarily true. It is, in fact, advantageous to use the two tracers together, and we recommend systematically using tritium in future studies.
                                            
                                            
                                        Ralf Loritz, Markus Hrachowitz, Malte Neuper, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 25, 147–167, https://doi.org/10.5194/hess-25-147-2021, https://doi.org/10.5194/hess-25-147-2021, 2021
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                                                This study investigates the role and value of distributed rainfall in the runoff generation of a mesoscale catchment. We compare the performance of different hydrological models at different periods and show that a distributed model driven by distributed rainfall yields improved performances only during certain periods. We then step beyond this finding and develop a spatially adaptive model that is capable of dynamically adjusting its spatial model structure in time.
                                            
                                            
                                        Conrad Jackisch, Samuel Knoblauch, Theresa Blume, Erwin Zehe, and Sibylle K. Hassler
                                    Biogeosciences, 17, 5787–5808, https://doi.org/10.5194/bg-17-5787-2020, https://doi.org/10.5194/bg-17-5787-2020, 2020
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                                                We developed software to calculate the root water uptake (RWU) of beech tree roots from soil moisture dynamics. We present our approach and compare RWU to measured sap flow in the tree stem. The study relates to two sites that are similar in topography and weather but with contrasting soils. While sap flow is very similar between the two sites, the RWU is different. This suggests that soil characteristics have substantial influence. Our easy-to-implement RWU estimate may help further studies.
                                            
                                            
                                        Uwe Ehret, Rik van Pruijssen, Marina Bortoli, Ralf Loritz, Elnaz Azmi, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 24, 4389–4411, https://doi.org/10.5194/hess-24-4389-2020, https://doi.org/10.5194/hess-24-4389-2020, 2020
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                                                In this paper we propose adaptive clustering as a new method for reducing the computational efforts of distributed modelling. It consists of identifying similar-acting model elements during the runtime, clustering them, running the model for just a few representatives per cluster, and mapping their results to the remaining model elements in the cluster. With the example of a hydrological model, we show that this saves considerable computation time, while largely maintaining the output quality.
                                            
                                            
                                        Mirko Mälicke, Sibylle K. Hassler, Theresa Blume, Markus Weiler, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 24, 2633–2653, https://doi.org/10.5194/hess-24-2633-2020, https://doi.org/10.5194/hess-24-2633-2020, 2020
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                                                We could show that distributed soil moisture time series bear a considerable amount of information about dynamic changes in soil moisture. We developed a new method to describe spatial patterns and analyze their persistency. By combining uncertainty propagation with information theory, we were able to calculate the information content of spatial similarity with respect to measurement uncertainty. This does help to understand when and why the soil is drying in an organized manner.
                                            
                                            
                                        Brian Berkowitz and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 24, 1831–1858, https://doi.org/10.5194/hess-24-1831-2020, https://doi.org/10.5194/hess-24-1831-2020, 2020
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                                                We present a 
                                            
                                        blueprintfor a unified modelling framework to quantify chemical transport in both surface water and groundwater systems. There has been extensive debate over recent decades, particularly in the surface water literature, about how to explain and account for long travel times of chemical species that are distinct from water flow (rainfall-runoff) travel times. We suggest a powerful modelling framework known to be robust and effective from the field of groundwater hydrology.
Conrad Jackisch, Kai Germer, Thomas Graeff, Ines Andrä, Katrin Schulz, Marcus Schiedung, Jaqueline Haller-Jans, Jonas Schneider, Julia Jaquemotte, Philipp Helmer, Leander Lotz, Andreas Bauer, Irene Hahn, Martin Šanda, Monika Kumpan, Johann Dorner, Gerrit de Rooij, Stefan Wessel-Bothe, Lorenz Kottmann, Siegfried Schittenhelm, and Wolfgang Durner
                                    Earth Syst. Sci. Data, 12, 683–697, https://doi.org/10.5194/essd-12-683-2020, https://doi.org/10.5194/essd-12-683-2020, 2020
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                                                Soil water content and matric potential are central hydrological state variables. A large variety of automated probes and sensor systems for field monitoring exist. In a field experiment under idealised conditions we compared 15 systems for soil moisture and 14 systems for matric potential. The individual records of one system agree well with the others. Most records are also plausible. However, the absolute values of the different measuring systems span a very large range of possible truths.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Wolfgang Wilcke, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 23, 4249–4267, https://doi.org/10.5194/hess-23-4249-2019, https://doi.org/10.5194/hess-23-4249-2019, 2019
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                                                We present our hydrological LAST-Model to simulate preferential soil water flow and tracer transport in macroporous soils. It relies on a Lagrangian perspective of the movement of discrete water particles carrying tracer masses through the subsoil and is hence an alternative approach to common models. Sensitivity analyses reveal the physical validity of the model concept and evaluation tests show that LAST can depict well observed tracer mass profiles with fingerprints of preferential flow.
                                            
                                            
                                        Axel Kleidon, Erwin Zehe, and Ralf Loritz
                                        Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2019-52, https://doi.org/10.5194/esd-2019-52, 2019
                                    Manuscript not accepted for further review 
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                                                Many fluxes in Earth systems are not homogeneously distributed across space, but occur highly concentrated in structures, such as turbulent eddies, river networks, vascular networks of plants, or human-made infrastructures.  Yet, the highly-organized nature of these fluxes is typically only described at a rudimentary level, if at all.  We propose that it requires a novel approach to describe these structures that focuses on the work done to build and maintain these structures, and the feedbacks.
                                            
                                            
                                        Ralf Loritz, Axel Kleidon, Conrad Jackisch, Martijn Westhoff, Uwe Ehret, Hoshin Gupta, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 23, 3807–3821, https://doi.org/10.5194/hess-23-3807-2019, https://doi.org/10.5194/hess-23-3807-2019, 2019
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                                                In this study, we develop a topographic index explaining hydrological similarity within a energy-centered framework, with the observation that the majority of potential energy is dissipated when rainfall becomes runoff.
                                            
                                            
                                        Erwin Zehe, Ralf Loritz, Conrad Jackisch, Martijn Westhoff, Axel Kleidon, Theresa Blume, Sibylle K. Hassler, and Hubert H. Savenije
                                    Hydrol. Earth Syst. Sci., 23, 971–987, https://doi.org/10.5194/hess-23-971-2019, https://doi.org/10.5194/hess-23-971-2019, 2019
                            Martijn Westhoff, Axel Kleidon, Stan Schymanski, Benjamin Dewals, Femke Nijsse, Maik Renner, Henk Dijkstra, Hisashi Ozawa, Hubert Savenije, Han Dolman, Antoon Meesters, and Erwin Zehe
                                        Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2019-6, https://doi.org/10.5194/esd-2019-6, 2019
                                    Publication in ESD not foreseen 
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                                                Even models relying on physical laws have parameters that need to be measured or estimated. Thermodynamic optimality principles potentially offer a way to reduce the number of estimated parameters by stating that a system evolves to an optimum state. These principles have been applied successfully within the Earth system, but it is often unclear what to optimize and how. In this review paper we identify commonalities between different successful applications as well as some doubtful applications.
                                            
                                            
                                        Nevil Quinn, Günter Blöschl, András Bárdossy, Attilio Castellarin, Martyn Clark, Christophe Cudennec, Demetris Koutsoyiannis, Upmanu Lall, Lubomir Lichner, Juraj Parajka, Christa D. Peters-Lidard, Graham Sander, Hubert Savenije, Keith Smettem, Harry Vereecken, Alberto Viglione, Patrick Willems, Andy Wood, Ross Woods, Chong-Yu Xu, and Erwin Zehe
                                    Proc. IAHS, 380, 3–8, https://doi.org/10.5194/piahs-380-3-2018, https://doi.org/10.5194/piahs-380-3-2018, 2018
                            Nevil Quinn, Günter Blöschl, András Bárdossy, Attilio Castellarin, Martyn Clark, Christophe Cudennec, Demetris Koutsoyiannis, Upmanu Lall, Lubomir Lichner, Juraj Parajka, Christa D. Peters-Lidard, Graham Sander, Hubert Savenije, Keith Smettem, Harry Vereecken, Alberto Viglione, Patrick Willems, Andy Wood, Ross Woods, Chong-Yu Xu, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 22, 5735–5739, https://doi.org/10.5194/hess-22-5735-2018, https://doi.org/10.5194/hess-22-5735-2018, 2018
                            Mirko Mälicke, Sibylle K. Hassler, Markus Weiler, Theresa Blume, and Erwin Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-396, https://doi.org/10.5194/hess-2018-396, 2018
                                    Manuscript not accepted for further review 
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                                                In this study we use time dependent variograms to identify periods of organized soil moisture during drying. We could identify emerging spatial patterns which imply periods of terrestrial control on soil moisture organization. The coupling of time dependent variograms with density based clustering is a new approach to detect similarity in spatial patterns. The presented method is useful to describe states of organization and improve kriging workflows by extending their prerequisites.
                                            
                                            
                                        Ralf Loritz, Hoshin Gupta, Conrad Jackisch, Martijn Westhoff, Axel Kleidon, Uwe Ehret, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 22, 3663–3684, https://doi.org/10.5194/hess-22-3663-2018, https://doi.org/10.5194/hess-22-3663-2018, 2018
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                                                In this study we explore the role of spatially distributed information on hydrological modeling. For that, we develop and test an approach which draws upon information theory and thermodynamic reasoning. We show that the proposed set of methods provide a powerful framework for understanding and diagnosing how and when process organization and functional similarity of hydrological systems emerge in time and, hence, when which landscape characteristic is important in a model application.
                                            
                                            
                                        Simon Höllering, Jan Wienhöfer, Jürgen Ihringer, Luis Samaniego, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 22, 203–220, https://doi.org/10.5194/hess-22-203-2018, https://doi.org/10.5194/hess-22-203-2018, 2018
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                                                Hydrological fingerprints are introduced as response targets for sensitivity analysis and combined with a conventional approach using streamflow data for a temporally resolved sensitivity analysis. The joint benefit of both approaches is presented for several headwater catchments. The approach allows discerning a clarified pattern for parameter influences pinpointed to diverse response characteristics and detecting even slight regional differences.
                                            
                                            
                                        Lisa Angermann, Conrad Jackisch, Niklas Allroggen, Matthias Sprenger, Erwin Zehe, Jens Tronicke, Markus Weiler, and Theresa Blume
                                    Hydrol. Earth Syst. Sci., 21, 3727–3748, https://doi.org/10.5194/hess-21-3727-2017, https://doi.org/10.5194/hess-21-3727-2017, 2017
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                                                This study investigates the temporal dynamics and response velocities of lateral preferential flow at the hillslope. The results are compared to catchment response behavior to infer the large-scale implications of the observed processes. A large portion of mobile water flows through preferential flow paths in the structured soils, causing an immediate discharge response. The study presents a methodological approach to cover the spatial and temporal domain of these highly heterogeneous processes.
                                            
                                            
                                        Conrad Jackisch, Lisa Angermann, Niklas Allroggen, Matthias Sprenger, Theresa Blume, Jens Tronicke, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 3749–3775, https://doi.org/10.5194/hess-21-3749-2017, https://doi.org/10.5194/hess-21-3749-2017, 2017
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                                                Rapid subsurface flow in structured soils facilitates fast vertical and lateral redistribution of event water. We present its in situ exploration through local measurements and irrigation experiments. Special emphasis is given to a coherent combination of hydrological and geophysical methods. The study highlights that form and function operate as conjugated pairs. Dynamic imaging through time-lapse GPR was key to observing both and to identifying hydrologically relevant structures.
                                            
                                            
                                        Simon Paul Seibert, Conrad Jackisch, Uwe Ehret, Laurent Pfister, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 2817–2841, https://doi.org/10.5194/hess-21-2817-2017, https://doi.org/10.5194/hess-21-2817-2017, 2017
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                                                Runoff production mechanisms and their corresponding physiographic controls continue to pose major research challenges in catchment hydrology. We propose innovative data-driven diagnostic signatures for overcoming the prevailing status quo in inter-comparison studies. Specifically, we present dimensionless double mass curves which allow us to infer information on runoff generation at the seasonal and annual timescales. The method is based on commonly available data.
                                            
                                            
                                        Ralf Loritz, Sibylle K. Hassler, Conrad Jackisch, Niklas Allroggen, Loes van Schaik, Jan Wienhöfer, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 21, 1225–1249, https://doi.org/10.5194/hess-21-1225-2017, https://doi.org/10.5194/hess-21-1225-2017, 2017
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                                                In this study we examine whether we can step beyond the qualitative character of perceptual models by using them as a blueprint for setting up representative hillslope models. Thereby we test the hypothesis of whether a single hillslope can represent the functioning of an entire lower mesoscale catchment in a spatially aggregated way.
                                            
                                            
                                        Benjamin Müller, Matthias Bernhardt, Conrad Jackisch, and Karsten Schulz
                                    Hydrol. Earth Syst. Sci., 20, 3765–3775, https://doi.org/10.5194/hess-20-3765-2016, https://doi.org/10.5194/hess-20-3765-2016, 2016
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                                                A technology for the spatial derivation of soil texture classes is presented. Information about soil texture is key for predicting the local and regional hydrological cycle. It is needed for the calculation of soil water movement, the share of surface runoff, the evapotranspiration rate and others. Nevertheless, the derivation of soil texture classes is expensive and time-consuming. The presented technique uses soil samples and remotely sensed data for estimating their spatial distribution.
                                            
                                            
                                        Simon Paul Seibert, Uwe Ehret, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 20, 3745–3763, https://doi.org/10.5194/hess-20-3745-2016, https://doi.org/10.5194/hess-20-3745-2016, 2016
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                                                While the assessment of "vertical" (magnitude) errors of streamflow simulations is standard practice, "horizontal" (timing) errors are rarely considered. To assess their role, we propose a method to quantify both errors simultaneously which closely resembles visual hydrograph comparison. Our results reveal  differences in time–magnitude error statistics for different flow conditions. The proposed method thus offers novel perspectives for model diagnostics and evaluation.
                                            
                                            
                                        Erwin Zehe and Conrad Jackisch
                                    Hydrol. Earth Syst. Sci., 20, 3511–3526, https://doi.org/10.5194/hess-20-3511-2016, https://doi.org/10.5194/hess-20-3511-2016, 2016
                            Simon Höllering, Jürgen Ihringer, Luis Samaniego, and Erwin Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2016-249, https://doi.org/10.5194/hess-2016-249, 2016
                                    Preprint withdrawn 
                            M. Westhoff, E. Zehe, P. Archambeau, and B. Dewals
                                    Hydrol. Earth Syst. Sci., 20, 479–486, https://doi.org/10.5194/hess-20-479-2016, https://doi.org/10.5194/hess-20-479-2016, 2016
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                                                We derived mathematical formulations of relations between relative wetness and gradients driving run-off and evaporation for a one-box model such that, when conductances are optimized with the maximum power principle, the model leads exactly to a point on the Budyko curve.
With dry spells and dynamics in actual evaporation added, the model compared well with catchment observations without calibrating any parameter.
The maximum-power principle may thus be used to derive the Budyko curve.
                                            
                                            
                                        U. Scherer and E. Zehe
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hessd-12-3527-2015, https://doi.org/10.5194/hessd-12-3527-2015, 2015
                                    Revised manuscript not accepted 
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                                                This paper presents the development, parameterization and verification of a process-based soil erosion model for the catchment scale, which balances necessary complexity with greatest possible simplicity. We used the hydrologic model CATFLOW as a platform and further developed it to CATFLOW-SED by integrating approaches to simulate soil erosion. The model was validated on a hierarchy of scales which is characteristic for the governing processes.
                                            
                                            
                                        E. Zehe, U. Ehret, L. Pfister, T. Blume, B. Schröder, M. Westhoff, C. Jackisch, S. J. Schymanski, M. Weiler, K. Schulz, N. Allroggen, J. Tronicke, L. van Schaik, P. Dietrich, U. Scherer, J. Eccard, V. Wulfmeyer, and A. Kleidon
                                    Hydrol. Earth Syst. Sci., 18, 4635–4655, https://doi.org/10.5194/hess-18-4635-2014, https://doi.org/10.5194/hess-18-4635-2014, 2014
                            U. Ehret, H. V. Gupta, M. Sivapalan, S. V. Weijs, S. J. Schymanski, G. Blöschl, A. N. Gelfan, C. Harman, A. Kleidon, T. A. Bogaard, D. Wang, T. Wagener, U. Scherer, E. Zehe, M. F. P. Bierkens, G. Di Baldassarre, J. Parajka, L. P. H. van Beek, A. van Griensven, M. C. Westhoff, and H. C. Winsemius
                                    Hydrol. Earth Syst. Sci., 18, 649–671, https://doi.org/10.5194/hess-18-649-2014, https://doi.org/10.5194/hess-18-649-2014, 2014
                            J. Wienhöfer and E. Zehe
                                    Hydrol. Earth Syst. Sci., 18, 121–138, https://doi.org/10.5194/hess-18-121-2014, https://doi.org/10.5194/hess-18-121-2014, 2014
                            M. Liu, A. Bárdossy, and E. Zehe
                                    Hydrol. Earth Syst. Sci., 17, 4685–4699, https://doi.org/10.5194/hess-17-4685-2013, https://doi.org/10.5194/hess-17-4685-2013, 2013
                            E. Zehe, U. Ehret, T. Blume, A. Kleidon, U. Scherer, and M. Westhoff
                                    Hydrol. Earth Syst. Sci., 17, 4297–4322, https://doi.org/10.5194/hess-17-4297-2013, https://doi.org/10.5194/hess-17-4297-2013, 2013
                            M. C. Westhoff and E. Zehe
                                    Hydrol. Earth Syst. Sci., 17, 3141–3157, https://doi.org/10.5194/hess-17-3141-2013, https://doi.org/10.5194/hess-17-3141-2013, 2013
                            A. Kleidon, E. Zehe, U. Ehret, and U. Scherer
                                    Hydrol. Earth Syst. Sci., 17, 225–251, https://doi.org/10.5194/hess-17-225-2013, https://doi.org/10.5194/hess-17-225-2013, 2013
                            J. Wienhöfer, K. Germer, F. Lindenmaier, A. Färber, and E. Zehe
                                    Hydrol. Earth Syst. Sci., 13, 1145–1161, https://doi.org/10.5194/hess-13-1145-2009, https://doi.org/10.5194/hess-13-1145-2009, 2009
                            Related subject area
            Subject: Vadose Zone Hydrology | Techniques and Approaches: Modelling approaches
            
                    
                        
                            
                            
                                     
                                Quantitative soil characterization using the frequency domain electromagnetic induction method in heterogeneous fields
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Cold climates, complex hydrology: can a land surface model accurately simulate deep percolation?
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                From hydraulic root architecture models to efficient macroscopic sink terms including perirhizal resistance: quantifying accuracy and computational speed
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Quantifying the potential of using Soil Moisture Active Passive (SMAP) soil moisture variability to predict subsurface water dynamics
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Impacts of tile drainage on hydrology, soil biogeochemistry, and crop yield in the U.S. Midwestern agroecosystems
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Modeling 2D gravity-driven flow in unsaturated porous media for different infiltration rates
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Mesoscale permeability variations estimated from natural airflows in the decorated Cosquer Cave (southeastern France)
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Identification of parameter importance for benzene transport in the unsaturated zone using global sensitivity analysis
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Evapotranspiration prediction for European forest sites does not improve with assimilation of in situ soil water content data
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A comprehensive study of deep learning for soil moisture prediction
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Modelling groundwater recharge, actual evaporation, and transpiration in semi-arid sites of the Lake Chad basin: the role of soil and vegetation in groundwater recharge
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Predicting soil hydraulic properties for binary mixtures – concept and application for constructed Technosols
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Application of an improved distributed hydrological model based on the soil–gravel structure in the Niyang River basin, Qinghai–Tibet Plateau
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Assessment of the interactions between soil–biosphere–atmosphere (ISBA) land surface model soil hydrology, using four closed-form soil water relationships and several lysimeters
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Soil–vegetation–water interactions controlling solute flow and chemical weathering in volcanic ash soils of the high Andes
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Estimating vadose zone water fluxes from soil water monitoring data: a comprehensive field study in Austria
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Semi-continuum modeling of unsaturated porous media flow to explain Bauters' paradox
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Effects of dynamic changes of desiccation cracks on preferential flow: experimental investigation and numerical modeling
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Numerical assessment of morphological and hydraulic properties of moss, lichen and peat from a permafrost peatland
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A robust upwind mixed hybrid finite element method for transport in variably saturated porous media
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Stepping beyond perfectly mixed conditions in soil hydrological modelling using a Lagrangian approach
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Using machine learning to predict optimal electromagnetic induction instrument configurations for characterizing the shallow subsurface
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Gravity as a tool to improve the hydrologic mass budget in karstic areas
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A scaling procedure for straightforward computation of sorptivity
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                From hydraulic root architecture models to macroscopic representations of root hydraulics in soil water flow and land surface models
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Simulated or measured soil moisture: which one is adding more value to regional landslide early warning?
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Interaction of soil water and groundwater during the freezing–thawing cycle: field observations and numerical modeling
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Simulation of reactive solute transport in the critical zone: a Lagrangian model for transient flow and preferential transport
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Investigating the impact of exit effects on solute transport in macroporous media
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Comparison of root water uptake models in simulating CO2 and H2O fluxes and growth of wheat
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Understanding the mass, momentum, and energy transfer in the frozen soil with three levels of model complexities
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A field-validated surrogate crop model for predicting root-zone moisture and salt content in regions with shallow groundwater
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Characterizing uncertainty in the hydraulic parameters of oil sands mine reclamation covers and its influence on water balance predictions
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Simulating preferential soil water flow and tracer transport using the Lagrangian Soil Water and Solute Transport Model
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Assessment of simulated soil moisture from WRF Noah, Noah-MP, and CLM land surface schemes for landslide hazard application
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Efficient estimation of effective hydraulic properties of stratal undulating surface layer using time-lapse multi-channel GPR
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Partitioning snowmelt and rainfall in the critical zone: effects of climate type and soil properties
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A unique vadose zone model for shallow aquifers: the Hetao irrigation district, China
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Modelling of shallow water table dynamics using conceptual and physically based integrated surface-water–groundwater hydrologic models
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Capturing soil-water and groundwater interactions with an iterative feedback coupling scheme: new HYDRUS package for MODFLOW
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Caffeine vs. carbamazepine as indicators of wastewater pollution in a karst aquifer
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Predicting the soil water retention curve from the particle size distribution based on a pore space geometry containing slit-shaped spaces
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Technical note: Saturated hydraulic conductivity and textural heterogeneity of soils
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Water ages in the critical zone of long-term experimental sites in northern latitudes
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Impact of capillary rise and recirculation on simulated crop yields
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Soil hydraulic material properties and layered architecture from time-lapse GPR
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Root growth, water uptake, and sap flow of winter wheat in response to different soil water conditions
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Using lagged dependence to identify (de)coupled surface and subsurface soil moisture values
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 1: nonuniform infiltration and soil water redistribution
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
            
        
        Gaston Mendoza, Guillaume Blanchy, Ellen Van De Vijver, Jeroen Verhegge, Wim Cornelis, and Philippe De Smedt
                                    Hydrol. Earth Syst. Sci., 29, 2837–2850, https://doi.org/10.5194/hess-29-2837-2025, https://doi.org/10.5194/hess-29-2837-2025, 2025
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                                                This study explores two methods for predicting soil properties using the frequency domain electromagnetic induction technique in Belgium. We compared deterministic models, which often require extensive data adjustments, to empirical models. Our findings suggest that empirical models are generally more effective for soil analysis, although each method has its limitations. This research helps improve soil property prediction, crucial for agriculture and environmental management.
                                            
                                            
                                        Alireza Amani, Marie-Amélie Boucher, Alexandre R. Cabral, Vincent Vionnet, and Étienne Gaborit
                                    Hydrol. Earth Syst. Sci., 29, 2445–2465, https://doi.org/10.5194/hess-29-2445-2025, https://doi.org/10.5194/hess-29-2445-2025, 2025
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                                                Accurately estimating groundwater recharge using numerical models is particularly difficult in cold regions with snow and soil freezing. This study evaluated a physics-based model against high-resolution field measurements. Our findings highlight a need for a better representation of soil-freezing processes, offering a roadmap for future model development. This leads to more accurate models to aid in water resource management decisions in cold climates.
                                            
                                            
                                        Daniel Leitner, Andrea Schnepf, and Jan Vanderborght
                                    Hydrol. Earth Syst. Sci., 29, 1759–1782, https://doi.org/10.5194/hess-29-1759-2025, https://doi.org/10.5194/hess-29-1759-2025, 2025
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                                                Root water uptake strongly affects plant development and soil water balance. We use novel upscaling methods to develop land surface and crop models from detailed mechanistic models. We examine the mathematics behind this upscaling, pinpointing where errors occur. By simulating different crops and soils, we found that the accuracy loss varies based on root architecture and soil type. Our findings offer insights into balancing model complexity and accuracy for better predictions in agriculture.
                                            
                                            
                                        Aruna Kumar Nayak, Xiaoyong Xu, Steven K. Frey, Omar Khader, Andre R. Erler, David R. Lapen, Hazen A. J. Russell, and Edward A. Sudicky
                                    Hydrol. Earth Syst. Sci., 29, 215–244, https://doi.org/10.5194/hess-29-215-2025, https://doi.org/10.5194/hess-29-215-2025, 2025
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                                                Satellite remote sensing only measures the near-surface soil water content. We demonstrate that satellite-based near-surface soil water variability is a strong reflection of deeper subsurface water fluctuation and quantifies the response time differences between dynamics of satellite near-surface soil water and water in the deeper subsurface. Result support the use of satellite near-surface soil water measurements as indicators and/or predictors of water resources in  the deeper subsurface.
                                            
                                            
                                        Zewei Ma, Kaiyu Guan, Bin Peng, Wang Zhou, Robert Grant, Jinyun Tang, Murugesu Sivapalan, Ming Pan, Li Li, and Zhenong Jin
                                        Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2024-340, https://doi.org/10.5194/hess-2024-340, 2024
                                    Revised manuscript accepted for HESS 
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                                                We explore tile drainage’ impacts on the integrated hydrology-biogeochemistry-plant system, using ecosys with soil oxygen and microbe dynamics. We found that tile drainage lowers soil water content and improves soil oxygen levels, which helps crops grow better, especially during wet springs, and the developed root system also helps mitigate drought stress on dry summers. Overall, tile drainage increases crop resilience to climate change, making it a valuable future agricultural practice.
                                            
                                            
                                        Jakub Kmec and Miloslav Šír
                                    Hydrol. Earth Syst. Sci., 28, 4947–4970, https://doi.org/10.5194/hess-28-4947-2024, https://doi.org/10.5194/hess-28-4947-2024, 2024
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                                                The most mysterious part of the hydrological cycle is the infiltration of water into porous soil. In this process, water enters the soil, some of it is retained in the soil or evaporates, and the remaining water continues to move below and through the rock environment. The physical description of infiltration, specifically the dependence of the infiltration rate on the flow, shows very unusual features that are beyond the normal human experience. Our paper is devoted to their elucidation.
                                            
                                            
                                        Hugo Pellet, Bruno Arfib, Pierre Henry, Stéphanie Touron, and Ghislain Gassier
                                    Hydrol. Earth Syst. Sci., 28, 4035–4057, https://doi.org/10.5194/hess-28-4035-2024, https://doi.org/10.5194/hess-28-4035-2024, 2024
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                                                Conservation of decorated caves is highly dependent on airflows and is correlated with rock formation permeability. We present the first conceptual model of flows around the Paleolithic decorated Cosquer coastal cave (southeastern France), quantify air permeability, and show how its variation affects water levels inside the cave. This study highlights that airflows may change in karst unsaturated zones in response to changes in the water cycle and may thus be affected by climate change.
                                            
                                            
                                        Meirav Cohen, Nimrod Schwartz, and Ravid Rosenzweig
                                    Hydrol. Earth Syst. Sci., 28, 1585–1604, https://doi.org/10.5194/hess-28-1585-2024, https://doi.org/10.5194/hess-28-1585-2024, 2024
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                                                Contamination from fuel constituents poses a major threat to groundwater. However, studies devoted to identification of the driving parameters for fuel derivative transport in soils are scarce, and none have dealt with heterogeneous layered media. Here, we performed global sensitivity analysis (GSA) on a model of benzene transport to groundwater. The results identified the parameters controlling benzene transport in soils and showed that GSA is as an important tool for transport model analysis.
                                            
                                            
                                        Lukas Strebel, Heye Bogena, Harry Vereecken, Mie Andreasen, Sergio Aranda-Barranco, and Harrie-Jan Hendricks Franssen
                                    Hydrol. Earth Syst. Sci., 28, 1001–1026, https://doi.org/10.5194/hess-28-1001-2024, https://doi.org/10.5194/hess-28-1001-2024, 2024
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                                                We present results from using soil water content measurements from 13 European forest sites in a state-of-the-art land surface model. We use data assimilation to perform a combination of observed and modeled soil water content and show the improvements in the representation of soil water content. However, we also look at the impact on evapotranspiration and see no corresponding improvements.
                                            
                                            
                                        Yanling Wang, Liangsheng Shi, Yaan Hu, Xiaolong Hu, Wenxiang Song, and Lijun Wang
                                    Hydrol. Earth Syst. Sci., 28, 917–943, https://doi.org/10.5194/hess-28-917-2024, https://doi.org/10.5194/hess-28-917-2024, 2024
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                                                LSTM temporal modeling suits soil moisture prediction; attention mechanisms enhance feature learning efficiently, as their feature selection capabilities are proven through Transformer and attention–LSTM hybrids. Adversarial training strategies help extract additional information from time series’ data. SHAP analysis and t-SNE visualization reveal differences in encoded features across models. This work serves as a reference for time series’ data processing in hydrology problems.
                                            
                                            
                                        Christoph Neukum, Angela Morales-Santos, Melanie Ronelngar, Aminu Bala, and Sara Vassolo
                                    Hydrol. Earth Syst. Sci., 27, 3601–3619, https://doi.org/10.5194/hess-27-3601-2023, https://doi.org/10.5194/hess-27-3601-2023, 2023
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                                                A generalized approach that requires limited field data and well-established models is tested for assessing groundwater recharge in the southern Lake Chad basin. E and T coefficients are estimated with the FAO-dual Kc concept at six locations. Measured soil water content and chloride concentrations along vertical soil profiles together with different scenarios for E and T partitioning and a Bayesian calibration approach are used to simulate water flow and chloride transport using Hydrus-1D.
                                            
                                            
                                        Moreen Willaredt, Thomas Nehls, and Andre Peters
                                    Hydrol. Earth Syst. Sci., 27, 3125–3142, https://doi.org/10.5194/hess-27-3125-2023, https://doi.org/10.5194/hess-27-3125-2023, 2023
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                                                This study proposes a model to predict soil hydraulic properties (SHPs) of constructed Technosols for urban greening. The SHPs are determined by the Technosol composition and describe their capacity to store and supply water to plants. The model predicts SHPs of any binary mixture based on the SHPs of its two pure components, facilitating simulations of flow and transport processes before production. This can help create Technosols designed for efficient urban greening and water management.
                                            
                                            
                                        Pengxiang Wang, Zuhao Zhou, Jiajia Liu, Chongyu Xu, Kang Wang, Yangli Liu, Jia Li, Yuqing Li, Yangwen Jia, and Hao Wang
                                    Hydrol. Earth Syst. Sci., 27, 2681–2701, https://doi.org/10.5194/hess-27-2681-2023, https://doi.org/10.5194/hess-27-2681-2023, 2023
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                                                Considering the impact of the special geological and climatic conditions of the Qinghai–Tibet Plateau on the hydrological cycle, this study established the WEP-QTP hydrological model. The snow cover and gravel layers affected the temporal and spatial changes in frozen soil and improved the regulation of groundwater on the flow process. Ignoring he influence of special underlying surface conditions has a great impact on the hydrological forecast and water resource utilization in this area.
                                            
                                            
                                        Antoine Sobaga, Bertrand Decharme, Florence Habets, Christine Delire, Noële Enjelvin, Paul-Olivier Redon, Pierre Faure-Catteloin, and Patrick Le Moigne
                                    Hydrol. Earth Syst. Sci., 27, 2437–2461, https://doi.org/10.5194/hess-27-2437-2023, https://doi.org/10.5194/hess-27-2437-2023, 2023
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                                                Seven instrumented lysimeters are used to assess the simulation of the soil water dynamic in one land surface model. Four water potential and hydraulic conductivity closed-form equations, including one mixed form, are evaluated. One form is more relevant for simulating drainage, especially during intense drainage events. The soil profile heterogeneity of one parameter of the closed-form equations is shown to be important.
                                            
                                            
                                        Sebastián Páez-Bimos, Armando Molina, Marlon Calispa, Pierre Delmelle, Braulio Lahuatte, Marcos Villacís, Teresa Muñoz, and Veerle Vanacker
                                    Hydrol. Earth Syst. Sci., 27, 1507–1529, https://doi.org/10.5194/hess-27-1507-2023, https://doi.org/10.5194/hess-27-1507-2023, 2023
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                                                This study analyzes how vegetation influences soil hydrology, water fluxes, and chemical weathering rates in the high Andes. There are clear differences in the A horizon. The extent of soil chemical weathering varies depending on vegetation type. This difference is attributed mainly to the water fluxes. Our findings reveal that vegetation can modify soil properties in the uppermost horizon, altering the water balance, solutes, and chemical weathering throughout the entire soil profile.
                                            
                                            
                                        Marleen Schübl, Giuseppe Brunetti, Gabriele Fuchs, and Christine Stumpp
                                    Hydrol. Earth Syst. Sci., 27, 1431–1455, https://doi.org/10.5194/hess-27-1431-2023, https://doi.org/10.5194/hess-27-1431-2023, 2023
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                                                Estimating groundwater recharge through the unsaturated zone is a difficult task that is fundamentally associated with uncertainties. One of the few methods available is inverse modeling based on soil water measurements. Here, we used a nested sampling algorithm within a Bayesian probabilistic framework to assess model uncertainties at 14 sites in Austria. Further, we analyzed simulated recharge rates to identify factors influencing groundwater recharge rates and their temporal variability.
                                            
                                            
                                        Jakub Kmec, Miloslav Šír, Tomáš Fürst, and Rostislav Vodák
                                    Hydrol. Earth Syst. Sci., 27, 1279–1300, https://doi.org/10.5194/hess-27-1279-2023, https://doi.org/10.5194/hess-27-1279-2023, 2023
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                                                When rain falls on the ground, most of the water subsequently flows through the soil. The movement of water through the partially wet soil layer is surprisingly complicated. For decades, no mathematical model has been able to capture this process in its entire complexity. Here, we present a model that aims to solve this long-standing problem. In this paper, we show that the model correctly reproduces the transition between diffusion and preferential flow regimes.
                                            
                                            
                                        Yi Luo, Jiaming Zhang, Zhi Zhou, Juan P. Aguilar-Lopez, Roberto Greco, and Thom Bogaard
                                    Hydrol. Earth Syst. Sci., 27, 783–808, https://doi.org/10.5194/hess-27-783-2023, https://doi.org/10.5194/hess-27-783-2023, 2023
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                                                This paper describes an experiment and modeling of the hydrological response of desiccation cracks under long-term wetting–drying cycles. We developed a new dynamic dual-permeability model to quantify the dynamic evolution of desiccation cracks and associated preferential flow and moisture distribution. Compared to other models, the dynamic dual-permeability model could describe the experimental data much better, but it also provided an improved description of the underlying physics.
                                            
                                            
                                        Simon Cazaurang, Manuel Marcoux, Oleg S. Pokrovsky, Sergey V. Loiko, Artem G. Lim, Stéphane Audry, Liudmila S. Shirokova, and Laurent Orgogozo
                                    Hydrol. Earth Syst. Sci., 27, 431–451, https://doi.org/10.5194/hess-27-431-2023, https://doi.org/10.5194/hess-27-431-2023, 2023
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                                                Moss, lichen and peat samples are reconstructed using X-ray tomography. Most samples can be cut down to a representative volume based on porosity. However, only homogeneous samples could be reduced to a representative volume based on hydraulic conductivity. For heterogeneous samples, a devoted pore network model is computed. The studied samples are mostly highly porous and water-conductive. These results must be put into perspective with compressibility phenomena occurring in field tests.
                                            
                                            
                                        Anis Younes, Hussein Hoteit, Rainer Helmig, and Marwan Fahs
                                    Hydrol. Earth Syst. Sci., 26, 5227–5239, https://doi.org/10.5194/hess-26-5227-2022, https://doi.org/10.5194/hess-26-5227-2022, 2022
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                                                Despite its advantages for the simulation of flow in heterogeneous and fractured porous media, the mixed hybrid finite element method has been rarely used for transport as it suffers from strong unphysical oscillations. We develop here a new upwind scheme for the mixed hybrid finite element that can avoid oscillations. Numerical examples confirm the robustness of this new scheme for the simulation of contaminant transport in both saturated and unsaturated conditions.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Brian Berkowitz, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 26, 1615–1629, https://doi.org/10.5194/hess-26-1615-2022, https://doi.org/10.5194/hess-26-1615-2022, 2022
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                                                We present a (physically based) Lagrangian approach to simulate diffusive mixing processes on the pore scale beyond perfectly mixed conditions. Results show the feasibility of the approach for reproducing measured mixing times and concentrations of isotopes over pore sizes and that typical shapes of breakthrough curves (normally associated with non-uniform transport in heterogeneous soils) may also occur as a result of imperfect subscale mixing in a macroscopically homogeneous soil matrix.
                                            
                                            
                                        Kim Madsen van't Veen, Ty Paul Andrew Ferré, Bo Vangsø Iversen, and Christen Duus Børgesen
                                    Hydrol. Earth Syst. Sci., 26, 55–70, https://doi.org/10.5194/hess-26-55-2022, https://doi.org/10.5194/hess-26-55-2022, 2022
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                                                Geophysical instruments are often used in hydrological surveys. A geophysical model that couples electrical conductivity in the subsurface layers with measurements from an electromagnetic induction instrument was combined with a machine learning algorithm. The study reveals that this combination can estimate the identifiability of electrical conductivity in a layered soil and provide insight into the best way to configure the instrument for a specific field site.
                                            
                                            
                                        Tommaso Pivetta, Carla Braitenberg, Franci Gabrovšek, Gerald Gabriel, and Bruno Meurers
                                    Hydrol. Earth Syst. Sci., 25, 6001–6021, https://doi.org/10.5194/hess-25-6001-2021, https://doi.org/10.5194/hess-25-6001-2021, 2021
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                                                Gravimetry offers a valid complement to classical hydrologic measurements in order to characterize karstic systems in which the recharge process causes fast accumulation of large water volumes in the voids of the epi-phreatic system. In this contribution we show an innovative integration of gravimetric and hydrologic observations to constrain a hydrodynamic model of the Škocjan Caves (Slovenia). We demonstrate how the inclusion of gravity observations improves the water mass budget estimates.
                                            
                                            
                                        Laurent Lassabatere, Pierre-Emmanuel Peyneau, Deniz Yilmaz, Joseph Pollacco, Jesús Fernández-Gálvez, Borja Latorre, David Moret-Fernández, Simone Di Prima, Mehdi Rahmati, Ryan D. Stewart, Majdi Abou Najm, Claude Hammecker, and Rafael Angulo-Jaramillo
                                    Hydrol. Earth Syst. Sci., 25, 5083–5104, https://doi.org/10.5194/hess-25-5083-2021, https://doi.org/10.5194/hess-25-5083-2021, 2021
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                                                Soil sorptivity is a crucial parameter for the modeling of water infiltration into soils. The standard equation used to compute sorptivity from the soil water retention curve, the unsaturated hydraulic conductivity, and initial and final water contents may lead to erroneous estimates due to its complexity. This study proposes a new straightforward scaling procedure for estimations of sorptivity for four famous and commonly used hydraulic models.
                                            
                                            
                                        Jan Vanderborght, Valentin Couvreur, Felicien Meunier, Andrea Schnepf, Harry Vereecken, Martin Bouda, and Mathieu Javaux
                                    Hydrol. Earth Syst. Sci., 25, 4835–4860, https://doi.org/10.5194/hess-25-4835-2021, https://doi.org/10.5194/hess-25-4835-2021, 2021
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                                                Root water uptake is an important process in the terrestrial water cycle. How this process depends on soil water content, root distributions, and root properties is a soil–root hydraulic problem. We compare different approaches to implementing root hydraulics in macroscopic soil water flow and land surface models.
                                            
                                            
                                        Adrian Wicki, Per-Erik Jansson, Peter Lehmann, Christian Hauck, and Manfred Stähli
                                    Hydrol. Earth Syst. Sci., 25, 4585–4610, https://doi.org/10.5194/hess-25-4585-2021, https://doi.org/10.5194/hess-25-4585-2021, 2021
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                                                Soil moisture information was shown to be valuable for landslide prediction. Soil moisture was simulated at 133 sites in Switzerland, and the temporal variability was compared to the regional occurrence of landslides. We found that simulated soil moisture is a good predictor for landslides, and that the forecast goodness is similar to using in situ measurements. This encourages the use of models for complementing existing soil moisture monitoring networks for regional landslide early warning.
                                            
                                            
                                        Hong-Yu Xie, Xiao-Wei Jiang, Shu-Cong Tan, Li Wan, Xu-Sheng Wang, Si-Hai Liang, and Yijian Zeng
                                    Hydrol. Earth Syst. Sci., 25, 4243–4257, https://doi.org/10.5194/hess-25-4243-2021, https://doi.org/10.5194/hess-25-4243-2021, 2021
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                                                Freezing-induced groundwater migration and water table decline are widely observed, but quantitative understanding of these processes is lacking. By considering wintertime atmospheric conditions and occurrence of lateral groundwater inflow, a model coupling soil water and groundwater reproduced field observations of soil temperature, soil water content, and groundwater level well. The model results led to a clear understanding of the balance of the water budget during the freezing–thawing cycle.
                                            
                                            
                                        Mohammad Farzamian, Dario Autovino, Angelo Basile, Roberto De Mascellis, Giovanna Dragonetti, Fernando Monteiro Santos, Andrew Binley, and Antonio Coppola
                                    Hydrol. Earth Syst. Sci., 25, 1509–1527, https://doi.org/10.5194/hess-25-1509-2021, https://doi.org/10.5194/hess-25-1509-2021, 2021
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                                                Soil salinity is a serious threat in numerous arid and semi-arid areas of the world. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected lands efficiently. We demonstrate that rapid and non-invasive geophysical measurements modelled by advanced numerical analysis of the signals and coupled with hydrological modelling can provide valuable information to assess the spatio-temporal variability in soil salinity over large areas.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Julian Klaus, Brian Berkowitz, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 25, 1483–1508, https://doi.org/10.5194/hess-25-1483-2021, https://doi.org/10.5194/hess-25-1483-2021, 2021
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                                                The key innovation of the study is a method to simulate reactive solute transport in the vadose zone within a Lagrangian framework. We extend the LAST-Model with a method to account for non-linear sorption and first-order degradation processes during unsaturated transport of reactive substances in the matrix and macropores. Model evaluations using bromide and pesticide data from irrigation experiments under different flow conditions on various timescales show the feasibility of the method.
                                            
                                            
                                        Jérôme Raimbault, Pierre-Emmanuel Peyneau, Denis Courtier-Murias, Thomas Bigot, Jaime Gil Roca, Béatrice Béchet, and Laurent Lassabatère
                                    Hydrol. Earth Syst. Sci., 25, 671–683, https://doi.org/10.5194/hess-25-671-2021, https://doi.org/10.5194/hess-25-671-2021, 2021
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                                                Contaminant transport in soils is known to be affected by soil heterogeneities such as macropores. The transport properties of heterogeneous porous media can be studied in laboratory columns. However, the results reported in this study (a combination of breakthrough experiments, magnetic resonance imaging and computer simulations of transport) show that these properties can be largely affected by the boundary devices of the columns, thus highlighting the need to take their effect into account.
                                            
                                            
                                        Thuy Huu Nguyen, Matthias Langensiepen, Jan Vanderborght, Hubert Hüging, Cho Miltin Mboh, and Frank Ewert
                                    Hydrol. Earth Syst. Sci., 24, 4943–4969, https://doi.org/10.5194/hess-24-4943-2020, https://doi.org/10.5194/hess-24-4943-2020, 2020
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                                                The mechanistic Couvreur root water uptake (RWU) model that is based on plant hydraulics and links root system properties to RWU, water stress, and crop development can evaluate the impact of certain crop properties on crop performance in different environments and soils, while the Feddes RWU approach does not possess such flexibility. This study also shows the importance of modeling root development and how it responds to water deficiency to predict the impact of water stress on crop growth.
                                            
                                            
                                        Lianyu Yu, Yijian Zeng, and Zhongbo Su
                                    Hydrol. Earth Syst. Sci., 24, 4813–4830, https://doi.org/10.5194/hess-24-4813-2020, https://doi.org/10.5194/hess-24-4813-2020, 2020
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                                                Soil mass and heat transfer processes were represented in three levels of model complexities to understand soil freeze–thaw mechanisms. Results indicate that coupled mass and heat transfer models considerably improved simulations of the soil hydrothermal regime. Vapor flow and thermal effects on water flow are the main mechanisms for the improvements. Given the explicit consideration of airflow, vapor flow and its effects on heat transfer were enhanced during the freeze–thaw transition period.
                                            
                                            
                                        Zhongyi Liu, Zailin Huo, Chaozi Wang, Limin Zhang, Xianghao Wang, Guanhua Huang, Xu Xu, and Tammo Siert Steenhuis
                                    Hydrol. Earth Syst. Sci., 24, 4213–4237, https://doi.org/10.5194/hess-24-4213-2020, https://doi.org/10.5194/hess-24-4213-2020, 2020
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                                                We have developed an integrated surrogate model for arid irrigated areas with shallow groundwater that links crop growth with soil water and salinity in the vadose zone. The model recognizes that field capacity is reached when the matric potential is equal to the height above the groundwater table. The model applies areas with shallow groundwater for which only very few surrogate models are available for most surface irrigation systems in the world without suffering from high groundwater.
                                            
                                            
                                        M. Shahabul Alam, S. Lee Barbour, and Mingbin Huang
                                    Hydrol. Earth Syst. Sci., 24, 735–759, https://doi.org/10.5194/hess-24-735-2020, https://doi.org/10.5194/hess-24-735-2020, 2020
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                                                This study quantifies uncertainties in the prediction of long-term water balance for mine reclamation soil covers using random sampling of model parameter distributions. Parameter distributions were obtained from model optimization for field monitoring data. Variability in climate is a greater source of uncertainty than the model parameters in evaporation predictions, while climate variability and model parameters exert similar uncertainty on predictions of net percolation.
                                            
                                            
                                        Alexander Sternagel, Ralf Loritz, Wolfgang Wilcke, and Erwin Zehe
                                    Hydrol. Earth Syst. Sci., 23, 4249–4267, https://doi.org/10.5194/hess-23-4249-2019, https://doi.org/10.5194/hess-23-4249-2019, 2019
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                                                We present our hydrological LAST-Model to simulate preferential soil water flow and tracer transport in macroporous soils. It relies on a Lagrangian perspective of the movement of discrete water particles carrying tracer masses through the subsoil and is hence an alternative approach to common models. Sensitivity analyses reveal the physical validity of the model concept and evaluation tests show that LAST can depict well observed tracer mass profiles with fingerprints of preferential flow.
                                            
                                            
                                        Lu Zhuo, Qiang Dai, Dawei Han, Ningsheng Chen, and Binru Zhao
                                    Hydrol. Earth Syst. Sci., 23, 4199–4218, https://doi.org/10.5194/hess-23-4199-2019, https://doi.org/10.5194/hess-23-4199-2019, 2019
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                                                This study assesses the usability of WRF model-simulated soil moisture for landslide monitoring in northern Italy. In particular, three advanced land surface model schemes (Noah, Noah-MP, and CLM4) are used to provide multi-layer soil moisture data. The results have shown Noah-MP can provide the best landslide monitoring performance. It is also demonstrated that a single soil moisture sensor located in plain area has a high correlation with a significant proportion of the study area.
                                            
                                            
                                        Xicai Pan, Stefan Jaumann, Jiabao Zhang, and Kurt Roth
                                    Hydrol. Earth Syst. Sci., 23, 3653–3663, https://doi.org/10.5194/hess-23-3653-2019, https://doi.org/10.5194/hess-23-3653-2019, 2019
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                                                This study suggests an efficient approach to obtain plot-scale soil hydraulic properties for the shallow structural soils via non-invasive ground-penetrating radar measurements. Facilitated by spatial information of lateral water flow, this approach is more efficient than the widely used inversion approaches relying on intensive soil moisture monitoring. The acquisition of such quantitative information is of great interest to fields such as hydrology and precision agriculture.
                                            
                                            
                                        John C. Hammond, Adrian A. Harpold, Sydney Weiss, and Stephanie K. Kampf
                                    Hydrol. Earth Syst. Sci., 23, 3553–3570, https://doi.org/10.5194/hess-23-3553-2019, https://doi.org/10.5194/hess-23-3553-2019, 2019
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                                                Streamflow in high-elevation and high-latitude areas may be vulnerable to snow loss, making it important to quantify how snowmelt and rainfall are divided between soil storage, drainage below plant roots, evapotranspiration and runoff. We examine this separation in different climates and soils using a physically based model. Results show runoff may be reduced with snowpack decline in all climates. The mechanisms responsible help explain recent observations of streamflow sensitivity to snow loss.
                                            
                                            
                                        Zhongyi Liu, Xingwang Wang, Zailin Huo, and Tammo Siert Steenhuis
                                    Hydrol. Earth Syst. Sci., 23, 3097–3115, https://doi.org/10.5194/hess-23-3097-2019, https://doi.org/10.5194/hess-23-3097-2019, 2019
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                                                A novel approach is taken in simulating the hydrology of the vadose zone in areas with shallow groundwater. The model recognizes that field capacity is reached when the matric potential is equal to the height above the groundwater table. The model can be used in areas with shallow groundwater to optimize irrigation water use and minimize tailwater losses.
                                            
                                            
                                        Mohammad Bizhanimanzar, Robert Leconte, and Mathieu Nuth
                                    Hydrol. Earth Syst. Sci., 23, 2245–2260, https://doi.org/10.5194/hess-23-2245-2019, https://doi.org/10.5194/hess-23-2245-2019, 2019
                                    Short summary
                                    Short summary
                                            
                                                Modelling of shallow water table fluctuations is usually carried out using physically based numerical models. These models have notable limitations regarding intensive required data and computational burden. This paper presents an alternative modelling approach for modelling of such cases by introducing modifications to the calculation of groundwater recharge and saturated flow of a conceptual hydrologic model.
                                            
                                            
                                        Jicai Zeng, Jinzhong Yang, Yuanyuan Zha, and Liangsheng Shi
                                    Hydrol. Earth Syst. Sci., 23, 637–655, https://doi.org/10.5194/hess-23-637-2019, https://doi.org/10.5194/hess-23-637-2019, 2019
                                    Short summary
                                    Short summary
                                            
                                                Accurately capturing the soil-water–groundwater interaction is vital for all disciplines related to subsurface flow but is difficult when undergoing significant nonlinearity in the modeling system. A new soil-water flow package is developed to solve the switching-form Richards’ equation. A multi-scale water balance analysis joins unsaturated–saturated models at separated scales. The whole system is solved efficiently with an iterative feedback coupling scheme.
                                            
                                            
                                        Noam Zach Dvory, Yakov Livshitz, Michael Kuznetsov, Eilon Adar, Guy Gasser, Irena Pankratov, Ovadia Lev, and Alexander Yakirevich
                                    Hydrol. Earth Syst. Sci., 22, 6371–6381, https://doi.org/10.5194/hess-22-6371-2018, https://doi.org/10.5194/hess-22-6371-2018, 2018
                                    Short summary
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                                                This research is paramount given the significance of karst aquifers as essential drinking water sources. While CBZ is considered conservative, CAF is subject to sorption and degradation, and therefore each of these two pollutants can be considered effective tracers for specific assessment of aquifer contamination. The model presented in this paper shows how each of the mentioned contaminants could serve as a better tool for aquifer contamination characterization and its treatment.
                                            
                                            
                                        Chen-Chao Chang and Dong-Hui Cheng
                                    Hydrol. Earth Syst. Sci., 22, 4621–4632, https://doi.org/10.5194/hess-22-4621-2018, https://doi.org/10.5194/hess-22-4621-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                The soil water retention curve (SWRC) is fundamental to researching water flow and chemical transport in unsaturated media. However, the traditional prediction models underestimate the water content in the dry range of the SWRC. A method was therefore proposed to improve the estimation of the SWRC using a pore model containing slit-shaped spaces. The results show that the predicted SWRCs using the improved method reasonably approximated the measured SWRCs.
                                            
                                            
                                        Carlos García-Gutiérrez, Yakov Pachepsky, and Miguel Ángel Martín
                                    Hydrol. Earth Syst. Sci., 22, 3923–3932, https://doi.org/10.5194/hess-22-3923-2018, https://doi.org/10.5194/hess-22-3923-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Saturated hydraulic conductivity (Ksat) is an important soil parameter that highly depends on soil's particle size distribution (PSD). The nature of this dependency is explored in this work in two ways, (1) by using the information entropy as a heterogeneity parameter of the PSD and (2) by using descriptions of PSD in forms of textural triplets, different than the usual description in terms of the triplet of sand, silt, and clay contents.
                                            
                                            
                                        Matthias Sprenger, Doerthe Tetzlaff, Jim Buttle, Hjalmar Laudon, and Chris Soulsby
                                    Hydrol. Earth Syst. Sci., 22, 3965–3981, https://doi.org/10.5194/hess-22-3965-2018, https://doi.org/10.5194/hess-22-3965-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                We estimated water ages in the upper critical zone with a soil physical model (SWIS) and found that the age of water stored in the soil, as well as of water leaving the soil via evaporation, transpiration, or recharge, was younger the higher soil water storage (inverse storage effect). Travel times of transpiration and evaporation were different. We conceptualized the subsurface into fast and slow flow domains and the water was usually half as young in the fast as in the slow flow domain.
                                            
                                            
                                        Joop Kroes, Iwan Supit, Jos van Dam, Paul van Walsum, and Martin Mulder
                                    Hydrol. Earth Syst. Sci., 22, 2937–2952, https://doi.org/10.5194/hess-22-2937-2018, https://doi.org/10.5194/hess-22-2937-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Impact of upward flow by capillary rise and recirculation on crop yields is often neglected or underestimated. Case studies and model experiments are used to illustrate the impact of this upward flow in the Dutch delta. Neglecting upward flow results in yield reductions for grassland, maize and potatoes. Half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions; the other half from increased upward capillary rise.
                                            
                                            
                                        Stefan Jaumann and Kurt Roth
                                    Hydrol. Earth Syst. Sci., 22, 2551–2573, https://doi.org/10.5194/hess-22-2551-2018, https://doi.org/10.5194/hess-22-2551-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Ground-penetrating radar (GPR) is a noninvasive and nondestructive  measurement method to monitor the hydraulic processes precisely and efficiently. We analyze synthetic as well as measured data from the ASSESS test site and show that the analysis yields accurate estimates for the soil hydraulic material properties as well as for the subsurface architecture by comparing the results to references derived from time domain reflectometry (TDR) and subsurface architecture ground truth data.
                                            
                                            
                                        Gaochao Cai, Jan Vanderborght, Matthias Langensiepen, Andrea Schnepf, Hubert Hüging, and Harry Vereecken
                                    Hydrol. Earth Syst. Sci., 22, 2449–2470, https://doi.org/10.5194/hess-22-2449-2018, https://doi.org/10.5194/hess-22-2449-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Different crop growths had consequences for the parameterization of root water uptake models. The root hydraulic parameters of the Couvreur model but not the water stress parameters of the Feddes–Jarvis model could be constrained by the field data measured from rhizotron facilities. The simulated differences in transpiration from the two soils and the different water treatments could be confirmed by sap flow measurements. The Couvreur model predicted the ratios of transpiration fluxes better.
                                            
                                            
                                        Coleen D. U. Carranza, Martine J. van der Ploeg, and Paul J. J. F. Torfs
                                    Hydrol. Earth Syst. Sci., 22, 2255–2267, https://doi.org/10.5194/hess-22-2255-2018, https://doi.org/10.5194/hess-22-2255-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Remote sensing has been popular for mapping surface soil moisture. However, estimating subsurface values using surface soil moisture remains a challenge, as decoupling can occur. Depth-integrated soil moisture values used in hydrological models are affected by vertical variability. Using statistical methods, we investigate vertical variability between the surface (5 cm) and subsurface (40 cm) to quantify decoupling. We also discuss potential controls for decoupling during wet and dry conditions.
                                            
                                            
                                        Rafael Muñoz-Carpena, Claire Lauvernet, and Nadia Carluer
                                    Hydrol. Earth Syst. Sci., 22, 53–70, https://doi.org/10.5194/hess-22-53-2018, https://doi.org/10.5194/hess-22-53-2018, 2018
                                    Short summary
                                    Short summary
                                            
                                                Seasonal shallow water tables (WTs) in lowlands limit vegetation-buffer efficiency to control runoff pollution. Mechanistic models are needed to quantify true field efficiency. A new simplified algorithm for soil infiltration over WTs is tested against reference models and lab data showing WT effects depend on local settings but are negligible after 2 m depth. The algorithm is coupled to a complete vegetation buffer model in a companion paper to analyze pesticide and sediment control in situ.
                                            
                                            
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                Short summary
            We present a Lagrangian model for non-uniform soil water dynamics. It handles 2-D diffusion (based on a spatial random walk and implicit pore space redistribution) and 1-D advection in representative macropores (as film flow with dynamic interaction with the soil matrix). The interplay between the domains is calculated based on an energy-balance approach which does not require any additional parameterisation. Model tests give insight into the evolution of the non-uniform infiltration patterns.
            We present a Lagrangian model for non-uniform soil water dynamics. It handles 2-D diffusion...
            
         
 
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
             
             
            