Articles | Volume 30, issue 4
https://doi.org/10.5194/hess-30-1143-2026
© Author(s) 2026. 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-30-1143-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
26 Feb 2026
Research article |
| 26 Feb 2026
| 26 Feb 2026
Enhancing process interpretation with isotopes: potential discharge-isotope trade-offs in ecohydrological modelling of heavily managed lowland catchments
Hanwu Zheng
CORRESPONDING AUTHOR
Geography Institute and IRI THESys, Humboldt University of Berlin, Berlin, Germany
Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
Doerthe Tetzlaff
Geography Institute and IRI THESys, Humboldt University of Berlin, Berlin, Germany
Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
Northern Rivers Institute, School of Geosciences, University of Aberdeen, Aberdeen, UK
Christian Birkel
Department of Geography, University of Costa Rica, San Jose, Costa Rica
Songjun Wu
Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
Tobias Sauter
Geography Institute and IRI THESys, Humboldt University of Berlin, Berlin, Germany
Chris Soulsby
Northern Rivers Institute, School of Geosciences, University of Aberdeen, Aberdeen, UK
Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
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Songjun Wu, Doerthe Tetzlaff, Yi Zheng, and Chris Soulsby
Geosci. Model Dev., 19, 2257–2278, https://doi.org/10.5194/gmd-19-2257-2026, https://doi.org/10.5194/gmd-19-2257-2026, 2026
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We developed EcoTWIN v1.0, a new fully distributed tracer-aided ecohydrological model that tracks water, isotopes, and nutrients fluxes. The model was successfully tested in 17 large European catchments across diverse geological and climatic backgrounds. As a tracer-aided model, EcoTWIN not only captures flow paths but also estimates water ages/travel times, thus bridging hydrology with water quality. This opens new possibilities for understanding the synergy between water and nitrogen cycles.
Kristine Flacké Haualand, Marie Pontoppidan, Henning Åkesson, and Tobias Sauter
EGUsphere, https://doi.org/10.5194/egusphere-2026-643, https://doi.org/10.5194/egusphere-2026-643, 2026
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
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Melting glaciers worldwide cause changes in land surface type and elevation that may impact regional climate. In a weather and climate model, we find that these changes result in warming and less precipitation, particularly less snow, over Jostedalsbreen ice cap in western Norway. Most of these impacts are related to thinning of the ice cap and the associated lowering of the surface and reduction in orographic lifting of moist air masses. The findings suggest accelerated melting of the ice cap.
Phillip Schuster, Ana-Lena Tappe, Alexander Georgi, Christoph Schneider, Mia Janzen, and Tobias Sauter
EGUsphere, https://doi.org/10.5194/egusphere-2025-3461, https://doi.org/10.5194/egusphere-2025-3461, 2025
This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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We present MATILDA-Online, an open-source, cloud-based modeling toolkit, to support integrated water management in glacierized mountain regions. It integrates glacier and hydrology models with open data and cloud computing. Despite data scarcity, this tool empowers local professionals, students, and researchers to generate climate impact assessments, promoting informed decision-making. Despite its accessibility, effective calibration and interpretation still require expert knowledge.
Ann-Marie Ring, Dörthe Tetzlaff, Christian Birkel, and Chris Soulsby
Hydrol. Earth Syst. Sci., 29, 6663–6683, https://doi.org/10.5194/hess-29-6663-2025, https://doi.org/10.5194/hess-29-6663-2025, 2025
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During summer drought, a clear sub-daily cycling of atmospheric water vapour isotopes (δv) and plant xylem water isotopes (δxyl) was observed. δv daytime depletion was driven by evaporation and local atmospheric factors (entrainment). δxyl daytime enrichment was consistent with high vapor pressure deficit and stomatal regulation of transpiration. This sub-daily dataset provides unique insights on sub-daily cycling of stable water isotopes and can help constrain ecohydrological models.
Phillip Schuster, Azamat Osmonov, Alexander Georgi, Christoph Schneider, and Tobias Sauter
EGUsphere, https://doi.org/10.5194/egusphere-2025-3462, https://doi.org/10.5194/egusphere-2025-3462, 2025
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This study examines water resources in a high-mountain basin in Kyrgyzstan facing climate change. The applied MATILDA-Online toolkit aims to integrate scientific research with practical water management. Projections indicate severe glacier melt and a significant reduction in runoff by 2100, with earlier peak flows and increased dry periods. The main challenges are the limited number of observations and their low accuracy, as well as the substantial effort required for model calibration.
Pedro Henrique Lima Alencar, Saskia Arndt, Kei Namba, Márk Somogyvári, Frederik Bart, Fabio Brill, Juan F. Dueñas, Peter Feindt, Daniel Johnson, Nariman Mahmoodi, Christoph Merz, Subham Mukherjee, Katrin Nissen, Eva Nora Paton, Tobias Sauter, Dörthe Tetzlaff, Franziska Tügel, Thomas Vogelpohl, Stenka Valentinova Vulova, Behnam Zamani, and Hui Hui Zhang
Nat. Hazards Earth Syst. Sci., 25, 4043–4051, https://doi.org/10.5194/nhess-25-4043-2025, https://doi.org/10.5194/nhess-25-4043-2025, 2025
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As climate change escalates, the Berlin-Brandenburg region faces new challenges. Climate change-induced extreme events are expected to cause new conflicts to emerge and aggravate existing ones. To guide future research, we co-develop a list of key questions on climate and water challenges in the region. Our findings highlight the need for new research approaches. We expect this list to provide a roadmap for actionable knowledge production to address climate and water challenges in the region.
Wilhelm Furian and Tobias Sauter
Nat. Hazards Earth Syst. Sci., 25, 3779–3802, https://doi.org/10.5194/nhess-25-3779-2025, https://doi.org/10.5194/nhess-25-3779-2025, 2025
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Glacial lake outburst floods (GLOFs) continue to threaten high-mountain communities in Nepal. We simulate potential GLOF events from five glacial lakes in the Everest region during the 21st century using a 3D flood model and several breach and SSP scenarios. Large GLOFs could extend over 100 km and inundate 80 to 100 km of roads/trails, 735 to 1989 houses and 0.85 to 3.52 km2 of agricultural land. The results help to assess the changing GLOF impacts and support more accurate risk assessments.
Maria Magdalena Warter, Dörthe Tetzlaff, Chris Soulsby, Tobias Goldhammer, Daniel Gebler, Kati Vierikko, and Michael T. Monaghan
Hydrol. Earth Syst. Sci., 29, 2707–2725, https://doi.org/10.5194/hess-29-2707-2025, https://doi.org/10.5194/hess-29-2707-2025, 2025
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There is a lack of understanding of how urban aquatic nature-based solutions (aquaNBSs) affect ecohydrology and how they in turn are affected by urbanization and climate change. We use a multi-tracer approach of stable water isotopes, hydrochemistry, and microbial and macrophyte diversity to disentangle the effects of hydroclimate and urbanization. The results show potential limitations of aquaNBSs regarding water quality and biodiversity in response to hydroclimate and urban water sources.
Cong Jiang, Doerthe Tetzlaff, Songjun Wu, Christian Birkel, Hjalmar Laudon, and Chris Soulsby
EGUsphere, https://doi.org/10.5194/egusphere-2025-2533, https://doi.org/10.5194/egusphere-2025-2533, 2025
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We used a modelling approach supported by stable water isotopes to explore how forest management – such as conifer, broadleaf, and mixed tree–crop systems – affects water distribution and drought resilience in a drought-sensitive region of Germany. By representing forest type, density, and rooting depth, the model helps quantify and show how land use choices affect water availability and supports better land and water management decisions.
Maria Magdalena Warter, Dörthe Tetzlaff, Christian Marx, and Chris Soulsby
Nat. Hazards Earth Syst. Sci., 24, 3907–3924, https://doi.org/10.5194/nhess-24-3907-2024, https://doi.org/10.5194/nhess-24-3907-2024, 2024
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Streams are increasingly impacted by droughts and floods. Still, the amount of water needed for sustainable flows remains unclear and contested. A comparison of two streams in the Berlin–Brandenburg region of northeast Germany, using stable water isotopes, shows strong groundwater dependence with seasonal rainfall contributing to high/low flows. Understanding streamflow variability can help us assess the impacts of climate change on future water resource management.
Salim Goudarzi, Chris Soulsby, Jo Smith, Jamie Lee Stevenson, Alessandro Gimona, Scot Ramsay, Alison Hester, Iris Aalto, and Josie Geris
EGUsphere, https://doi.org/10.5194/egusphere-2024-2258, https://doi.org/10.5194/egusphere-2024-2258, 2024
Preprint archived
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Planting trees on farmlands is now considered as one of the potential solutions to climate change. Trees can suck CO2 out of our atmosphere and store it in their trunks and in the soil beneath them. They can promote biodiversity, protect against soil erosion and drought. They can even help reduce flood risk for downstream communities. But we need models that can tell us the likely impact of trees at different locations and scales. Our study provides such a model.
Annelies Voordendag, Brigitta Goger, Rainer Prinz, Tobias Sauter, Thomas Mölg, Manuel Saigger, and Georg Kaser
The Cryosphere, 18, 849–868, https://doi.org/10.5194/tc-18-849-2024, https://doi.org/10.5194/tc-18-849-2024, 2024
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Wind-driven snow redistribution affects glacier mass balance. A case study of Hintereisferner glacier in Austria used high-resolution observations and simulations to model snow redistribution. Simulations matched observations, showing the potential of the model for studying snow redistribution on other mountain glaciers.
Franziska Temme, David Farías-Barahona, Thorsten Seehaus, Ricardo Jaña, Jorge Arigony-Neto, Inti Gonzalez, Anselm Arndt, Tobias Sauter, Christoph Schneider, and Johannes J. Fürst
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Calibration of surface mass balance (SMB) models on regional scales is challenging. We investigate different calibration strategies with the goal of achieving realistic simulations of the SMB in the Monte Sarmiento Massif, Tierra del Fuego. Our results show that the use of regional observations from satellite data can improve the model performance. Furthermore, we compare four melt models of different complexity to understand the benefit of increasing the processes considered in the model.
Doerthe Tetzlaff, Aaron Smith, Lukas Kleine, Hauke Daempfling, Jonas Freymueller, and Chris Soulsby
Earth Syst. Sci. Data, 15, 1543–1554, https://doi.org/10.5194/essd-15-1543-2023, https://doi.org/10.5194/essd-15-1543-2023, 2023
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We present a comprehensive set of ecohydrological hydrometric and stable water isotope data of 2 years of data. The data set is unique as the different compartments of the landscape were sampled and the effects of a prolonged drought (2018–2020) captured by a marked negative rainfall anomaly (the most severe regional drought of the 21st century). Thus, the data allow the drought effects on water storage, flux and age dynamics, and persistence of lowland landscapes to be investigated.
Xiaoqiang Yang, Doerthe Tetzlaff, Chris Soulsby, and Dietrich Borchardt
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2022-239, https://doi.org/10.5194/gmd-2022-239, 2022
Preprint retracted
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We develop the catchment water quality assessment platform HiWaQ v1.0, which is compatible with multiple hydrological model structures. The nitrogen module (HiWaQ-N) and its coupling tests with two contrasting grid-based hydrological models demonstrate the robustness of the platform in estimating catchment N dynamics. With the unique design of the coupling flexibility, HiWaQ can leverage advancements in hydrological modelling and advance integrated catchment water quantity-quality assessments.
Guangxuan Li, Xi Chen, Zhicai Zhang, Lichun Wang, and Chris Soulsby
Hydrol. Earth Syst. Sci., 26, 5515–5534, https://doi.org/10.5194/hess-26-5515-2022, https://doi.org/10.5194/hess-26-5515-2022, 2022
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We developed a coupled flow–tracer model to understand the effects of passive storage on modeling hydrological function and isotope dynamics in a karst flow system. Models with passive storages show improvement in matching isotope dynamics performance, and the improved performance also strongly depends on the number and location of passive storages. Our results also suggested that the solute transport is primarily controlled by advection and hydrodynamic dispersion in the steep hillslope unit.
Aaron Smith, Doerthe Tetzlaff, Jessica Landgraf, Maren Dubbert, and Chris Soulsby
Biogeosciences, 19, 2465–2485, https://doi.org/10.5194/bg-19-2465-2022, https://doi.org/10.5194/bg-19-2465-2022, 2022
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This research utilizes high-spatiotemporal-resolution soil and vegetation measurements, including water stable isotopes, within an ecohydrological model to partition water flux dynamics and identify flow paths and durations. Results showed high vegetation water use and high spatiotemporal dynamics of vegetation water source and vegetation isotopes. The evaluation of these dynamics further revealed relatively fast flow paths through both shallow soil and vegetation.
Jessica Landgraf, Dörthe Tetzlaff, Maren Dubbert, David Dubbert, Aaron Smith, and Chris Soulsby
Hydrol. Earth Syst. Sci., 26, 2073–2092, https://doi.org/10.5194/hess-26-2073-2022, https://doi.org/10.5194/hess-26-2073-2022, 2022
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Using water stable isotopes, we studied from which water source (lake water, stream water, groundwater, or soil water) two willows were taking their water. We monitored the environmental conditions (e.g. air temperature and soil moisture) and the behaviour of the trees (water flow in the stem). We found that the most likely water sources of the willows were the upper soil layers but that there were seasonal dynamics.
Saúl Arciniega-Esparza, Christian Birkel, Andrés Chavarría-Palma, Berit Arheimer, and José Agustín Breña-Naranjo
Hydrol. Earth Syst. Sci., 26, 975–999, https://doi.org/10.5194/hess-26-975-2022, https://doi.org/10.5194/hess-26-975-2022, 2022
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In the humid tropics, a notoriously data-scarce region, we need to find alternatives in order to reasonably apply hydrological models. Here, we tested remotely sensed rainfall data in order to drive a model for Costa Rica, and we evaluated the simulations against evapotranspiration satellite products. We found that our model was able to reasonably simulate the water balance and streamflow dynamics of over 600 catchments where the satellite data helped to reduce the model uncertainties.
Aaron J. Neill, Christian Birkel, Marco P. Maneta, Doerthe Tetzlaff, and Chris Soulsby
Hydrol. Earth Syst. Sci., 25, 4861–4886, https://doi.org/10.5194/hess-25-4861-2021, https://doi.org/10.5194/hess-25-4861-2021, 2021
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Structural changes (cover and height of vegetation plus tree canopy characteristics) to forests during regeneration on degraded land affect how water is partitioned between streamflow, groundwater recharge and evapotranspiration. Partitioning most strongly deviates from baseline conditions during earlier stages of regeneration with dense forest, while recovery may be possible as the forest matures and opens out. This has consequences for informing sustainable landscape restoration strategies.
Mikael Gillefalk, Dörthe Tetzlaff, Reinhard Hinkelmann, Lena-Marie Kuhlemann, Aaron Smith, Fred Meier, Marco P. Maneta, and Chris Soulsby
Hydrol. Earth Syst. Sci., 25, 3635–3652, https://doi.org/10.5194/hess-25-3635-2021, https://doi.org/10.5194/hess-25-3635-2021, 2021
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We used a tracer-aided ecohydrological model to quantify water flux–storage–age interactions for three urban vegetation types: trees, shrub and grass. The model results showed that evapotranspiration increased in the order shrub < grass < trees during one growing season. Additionally, we could show how
infiltration hotspotscreated by runoff from sealed onto vegetated surfaces can enhance both evapotranspiration and groundwater recharge.
Aaron Smith, Doerthe Tetzlaff, Lukas Kleine, Marco Maneta, and Chris Soulsby
Hydrol. Earth Syst. Sci., 25, 2239–2259, https://doi.org/10.5194/hess-25-2239-2021, https://doi.org/10.5194/hess-25-2239-2021, 2021
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We used a tracer-aided ecohydrological model on a mixed land use catchment in northeastern Germany to quantify water flux–storage–age interactions at four model grid resolutions. The model's ability to reproduce spatio-temporal flux–storage–age interactions decreases with increasing model grid sizes. Similarly, larger model grids showed vegetation-influenced changes in blue and green water partitioning. Simulations reveal the value of measured soil and stream isotopes for model calibration.
Jenna R. Snelgrove, James M. Buttle, Matthew J. Kohn, and Dörthe Tetzlaff
Hydrol. Earth Syst. Sci., 25, 2169–2186, https://doi.org/10.5194/hess-25-2169-2021, https://doi.org/10.5194/hess-25-2169-2021, 2021
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Co-evolution of plant and soil water isotopic composition throughout the growing season in a little-studied northern mixed forest landscape was explored. Marked inter-specific differences in the isotopic composition of xylem water relative to surrounding soil water occurred, despite thin soil cover constraining inter-species differences in rooting depths. We provide potential explanations for differences in temporal evolution of xylem water isotopic composition in this northern landscape.
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Short summary
Ecohydrological processes in heavily managed catchments are often inadequately represented in models. We applied a tracer-aided model STARR (Spatially distributed Tracer-Aided Rainfall-Runoff) in an ET (evapotranspiration)-dominated region (the Middle Spree, NE Germany) with major management impacts. Water isotopes were useful in identifying runoff contributions and partitioning ET even at sparse resolution. Trade-offs between discharge- and isotope-based calibrations could be partially mitigated by integrating more process-based conceptualizations into the model.
Ecohydrological processes in heavily managed catchments are often inadequately represented in...
