Bartolomé et al. (2025) Records of past flood in caves of the Central Pyrenees

Identification

• Journal: Mètode Revista de difusió de la investigació
• Year: 2025
• Date: 2025-11-12
• Authors: Miguel Bartolomé, Reyes Giménez, Guillermo Pérez‐Villar, Marc Luetscher, Heather Stoll, Ana Moreno, Mikel Calle, Juan Antonio Ballesteros‐Cánovas, Gerardo Benito
• DOI: 10.7203/metode.15.30175

Research Groups

• Department of Geology, Spanish National Museum of Natural Sciences (CSIC)
• Swiss Institute for Speleology and Karst Studies (SISKA)
• Department of Earth Sciences, Geological Institute of Switzerland
• Department of Geoenvironmental Processes and Global Change, Pyrenean Institute of Ecology (CSIC)
• Department of Earth Sciences, University of Zaragoza
• Department of Geodynamics, Stratigraphy and Palaeontology, Complutense University of Madrid

Short Summary

This paper advocates for and demonstrates an integrated approach to reconstruct and quantify past flood events using sedimentary evidence from caves, particularly stalagmites and clastic infills, combined with karst hydraulic modeling and monitoring. The study highlights the method's potential to extend flood records beyond instrumental data, improving long-term flood risk assessment in the Central Pyrenees under climate change.

Objective

• To advance an integrated methodology for reconstructing and quantifying past flood magnitudes by analyzing sedimentary evidence in caves (stalagmites and clastic infills), alongside karst hydraulic models and water-level monitoring, thereby improving the understanding and prediction of long-term flood variability in the Central Pyrenees in the context of global warming.

Study Configuration

• Spatial Scale: Central Pyrenees, including specific cave systems in the Lecherines and Collarada massifs (e.g., Las Güixas, El Rebeco, Esjamundo caves in Villanúa area), Artiguo Bajo cave, and Cañón de Aso cave in Ordesa and Monte Perdido National Park.
• Temporal Scale: Decadal to millennial scales for paleoflood records, with examples from recent instrumental records (1981-2015, 1996, 2012, 2024) and historical records (1977, 1982).

Methodology and Data

• Models used: Karst hydraulic models, hydrological models, infiltration models, 3D models of cave morphology.
• Data sources:
  • Sedimentary Evidence: Stalagmites (carbonate deposits, detrital sand/silt layers), clastic infills/deposits from caves.
  • Geochronological Dating: Uranium–thorium (U-Th) dating for speleothems, Optically Stimulated Luminescence (OSL) and radiocarbon (14C) for clastic sediments.
  • Monitoring Data: Water-level monitoring, flow rate monitoring, meteorological station rainfall data.
  • Historical Records: Documentary descriptions, limnimarks on buildings and bridges.
  • Instrumental Records: Rainfall accumulation (e.g., 178 mm in 70 minutes, 153 mm/h, 200 mm in 48 hours, 288 mm in less than 48 hours, 771.8 mm in 24 hours), river discharge (e.g., 4,200 m³/s to 5,500 m³/s).

Main Results

• Caves, particularly speleothems and clastic infills, are demonstrated as valuable, precisely datable archives for reconstructing past flood events over broad temporal ranges (centuries to millennia).
• An integrated approach combining continuous cave monitoring, karst hydraulic modeling (including 3D cave morphology), and geochronological dating is essential for accurately quantifying past flood magnitudes from cave records.
• Case studies from Central Pyrenean caves illustrate the method's efficacy:
  • Stalagmites in Esjamundo cave recorded past rare rainfall events, estimated between 100 mm and 220 mm in 24 hours, consistent with a 2012 event (222.3 mm in 24 hours).
  • Artiguo Bajo cave exhibits slackwater sand deposits 11 meters above the streambed, indicating past floods potentially linked to rainfall exceeding 100 mm in 24 hours, despite not being affected by similar events during current observations.
  • Cañón de Aso cave contains over 100 undated flood events in its sedimentary sequence, with preliminary modeling suggesting a flow rate of 55 m³/s is required for deposition at 4.4 meters elevation.
• The study emphasizes that understanding and integrating cave morphological changes caused by sediment transport is critical for accurate hydrological modeling and flood reconstruction.

Contributions

• Highlights the underutilized potential of stalagmites and cave detrital infills as high-resolution, long-term paleoflood archives, offering insights beyond the limited instrumental record.
• Proposes and demonstrates a novel, integrated methodology for quantifying past flood magnitudes in karstic caves, combining continuous monitoring, advanced hydraulic modeling (incorporating 3D cave structure and morphological changes), and precise geochronological dating.
• Provides concrete examples from the Central Pyrenees, showcasing how this integrated approach can reconstruct extreme flood events, thereby improving the understanding of long-term flood-climate relationships and future flood risks in karstic mountain regions.
• Emphasizes the critical role of considering dynamic cave morphology alterations due to sediment influx for accurate paleoflood reconstructions.

Funding

• MODKARST (nº 101107943 HORIZON TMA MSCA-GF-2022)
• PALEUNDA (Becas de Investigación Félix de Azara 2022, Diputación Provincial de Huesca)
• EXTreeM project (PID2021-1245730A-100) funded by MCIN/AEI/10.13039/501100011033
• Readapt project (TED2021-644 132266B-100) (Ministerio de Ciencia e Innovación Programa Estatal para Impulsar la Investigación Científico-Técnica y su Transferencia–PEICTI 2021-2023)

Citation

@article{Bartolomé2025Records,
  author = {Bartolomé, Miguel and Giménez, Reyes and Pérez‐Villar, Guillermo and Luetscher, Marc and Stoll, Heather and Moreno, Ana and Calle, Mikel and Ballesteros‐Cánovas, Juan Antonio and Benito, Gerardo},
  title = {Records of past flood in caves of the Central Pyrenees},
  journal = {Mètode Revista de difusió de la investigació},
  year = {2025},
  doi = {10.7203/metode.15.30175},
  url = {https://doi.org/10.7203/metode.15.30175}
}