ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. 1866-3591 Göttingen, Germany 10.5194/essd-2025-812 The WoKaS-Iso Database: Workflow for a Global Compilation of Oxygen-18 and Deuterium Records in Karst Springs and Cave Drip Water for Enhanced Understanding of Karst Systems Zang Yining 1 Treble Pauline C. https://orcid.org/0000-0002-1969-8555 2 3 Yoshimura Kei https://orcid.org/0000-0002-5761-1561 4 5 Pinza Jayson Gabriel 6 7 Zhang Fengbo 8 Çallı Kübra Özdemir https://orcid.org/0000-0003-0649-6687 1 Mei Xiaojun 9 Husic Admin https://orcid.org/0000-0002-4225-2252 10 Gessert Alena 11 Stroj Andrej 12 Andreo Bartolomé 13 Ladouche Bernard 14 15 Stumpp Christine 16 Mance Diana 17 Zagana Eleni 18 Huang Fen 19 Sappa Giuseppe https://orcid.org/0000-0003-0891-5021 20 Kunstmann Harald 21 22 Brielmann Heike 23 Zhou Hong 24 Wu Huaying 19 Garvelmann Jakob 21 25 Berglund James 26 Charlier Jean-Baptiste https://orcid.org/0000-0002-1268-8848 14 15 Lange Jens https://orcid.org/0000-0002-2023-8089 27 Barberá Fornell Juan Antonio 13 Pu Junbing 28 Katsanou Konstantina 29 Ren Kun 19 Toran Laura 30 Gill Laurence https://orcid.org/0000-0002-1599-1105 31 Filippini Maria https://orcid.org/0000-0001-5050-5072 32 Kralik Martin https://orcid.org/0000-0002-2944-0152 33 Mudarra Martínez Matías https://orcid.org/0000-0002-5045-6191 13 Zhao Min 34 Luo Mingming 24 Goldscheider Nico https://orcid.org/0000-0002-8428-5001 35 Lambrakis Nikolaos 18 Vita Pantaleone De 36 Xiao Qiong 19 Yu Shi 19 Iacurto Silvia 20 Coda Silvio 36 McCormack Ted 37 Allocca Vincenzo 36 Darling W. George 38 D’Alessandro Walter https://orcid.org/0000-0003-1724-0388 39 Guo Xulei https://orcid.org/0000-0001-9354-766X 24 Hu Yundi 40 Wang Zhijun 41 Kaminsky Eva 42 43 Faimon Jiří 44 45 Lang Marek 44 Pracný Pavel 44 Hartmann Andreas https://orcid.org/0000-0003-0407-742X 1 Institute of Groundwater Management, Technical University of Dresden, Dresden, 01069, Germany ANSTO, New Illawarra Road, Lucas Heights, NSW 2234, Australia School of Biological, Earth and Environmental Sciences, UNSW Sydney, Sydney NSW, 2052, Australia Institute of Industrial Science, The University of Tokyo, Kashiwa, Japan Japan Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan ECOSPHERE Research Group, University of Antwerp, Universiteitsplein 1C, 2610 Antwerp, Belgium Division of Soil and Water Management, KU Leuven, Celestijnenlaan 200E, 3001 Leuven, Belgium Ningbo River Management Center, Ningbo Water Resources Bureau, Ningbo 315000, China Merchant Marine College, Shanghai Maritime University, Shanghai 201306, China Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg 24061, USA Institute of Geography, Faculty of Sciences, University of P.J. Šafárik, 040 01 Košice, Slovakia Croatian Geological Survey, Sachsova 2, 10000 Zagreb, Croatia Department of Geology and Centre of Hydrogeology at the University of Malaga, 29071, Malaga, Spain BRGM, Univ Montpellier, Montpellier, France G-EAU, Univ Montpellier, AgroParisTech, BRGM, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France Institute of Soil Physics and Rural Water Management, Department of Landscape, Water and Infrastructure, BOKU University, Vienna, Austria Faculty of Physics, University of Rijeka, 51000, Rijeka, Croatia Laboratory of Hydrogeology, Department of Geology, Faculty of Natural Sciences, University of Patras, GR-26504 Patras, Greece Key Laboratory of Karst Dynamics, MNR and GZAR, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China Department of Civil, Constructional and Environmental Engineering (DICEA), Sapienza University of Rome, 00184 Rome, Italy Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Campus Alpin, D-82467 Garmisch-Partenkirchen, Germany Institute of Geography, University of Augsburg, D-86135 Augsburg, Germany Environment Agency Austria, Groundwater Unit, Spittelauer Laende 5, A-1090 Vienna, Austria School of Environmental Studies& Institute of Geological Survey, China University of Geosciences, Wuhan, 430074, Hubei, China Boden & grundwasser Allgäu GmbH, D-87527 Sonthofen, Germany Department of Civil and Environmental Engineering, University of Wisconsin – Platteville, Platteville, Wisconsin, USA Hydrology, University of Freiburg, 79098 Freiburg, Germany Chongqing Key Laboratory of Carbon Cycle and Carbon Regulation of Mountain Ecosystem, School of Geography and Tourism, Chongqing Normal University, Chongqing, 401331, China Department of Water Resources and Ecosystems, IHE Delft Institute for Water Education, Delft, Netherlands Department of Earth and Environmental Science, Temple University, Philadelphia, Pennsylvania, USA Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Ireland Department of Biological, Geological and Environmental Sciences—BiGeA, Alma Mater Studiorum, University of Bologna, Selmi 3, 40126 Bologna, Italy Department of Environmental Geosciences, Center for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria State Key Laboratory of Environmental Geochemistry (SKLEG), Institute of Geochemistry, Chinese Academy of Sciences (CAS), Guiyang, China Institute of Applied Geosciences, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany Department of Earth, Environmental and Resources Sciences (DiSTAR), University of Naples Federico II, Naples, Italy Geological Survey Ireland, Booterstown Avenue, Booterstown, Blackrock, Ireland British Geological Survey, Wallingford OX10 8BB, United Kingdom Istituto Nazionale di Geofisica e Vulcanologia – Sezione di Palermo, Via La Malfa 153, 90146 Palermo, Italy School of Geography and Environmental Science, Guizhou Normal University, Guiyang 550001, People’s Republic of China Faculty of Arts and Sciences, Beijing Normal University, Zhuhai 519087, China Karst and Cave Group, Geological Paleontological Department, Natural History Museum, Vienna, Austria Institute of Soil Physics and Rural Water Management, Department of Landscape, Water and Infrastructure, BOKU University, Vienna, Austria Department of Geological Sciences, Faculty of Science, Masaryk University, Brno, Czech Republic Czech Geological Survey, Brno Branch, Brno, Czech Republic 15 01 2026 2026 1 34 Copyright: © 2026 Yining Zang et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://essd.copernicus.org/preprints/essd-2025-812/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2025-812/essd-2025-812.pdf

For analysing karst hydrogeological systems, observations of karst springs and cave drips are considered indispensable. In addition to hydrometric observations, knowing the oxygen and hydrogen stable isotope ratios has improved the understanding of vadose zone and aquifer dynamics, likewise supporting system characterisation and modelling. However, limited accessibility and high costs of the analysis of stable isotopes in karst aquifers have hindered progress in karst research and impeded the accurate understanding of karst processes especially when it comes to comparative or large-scale studies. In this study, we present our workflow to compile the WoKaS-Iso database, the first extensive collection of time series data for Oxygen-18 and Deuterium isotopes in karst springs and cave drip water from diverse sources, encompassing publications, theses, reports, online archives, and collaborative initiatives worldwide. The database incorporates data sourced from 236 springs and 74 caves, comprising in total 997 time series (379 time series for the springs and 618 time series for the cave drip water). These datasets provide coverage across significant karst regions globally, spanning China, the USA, Europe, the Middle East, and Australia. Within datasets, 79% for springs and 68% for cave drip water exhibit resolutions finer than monthly intervals. In addition, by integrating isotopic records with ancillary environmental variables including spring discharge, cave drip rate, precipitation, and rainwater isotopes, the database offers a more comprehensive perspective on hydrological behaviours in karst aquifers, hence advancing hydrogeological characterisation and modelling. The WoKaS-Iso database not only deepens the understanding of the complex systems but also promotes sustainable water resource management as well as the potential to foster collaborative research. The database can be accessed at: <a href="https://doi.org/10.25532/OPARA-909">https://doi.org/10.25532/OPARA-909</a>.