Musy et al. (2025) Modeling a geologically complex volcanic watershed for integrated water resources management in Mt. Fuji, Japan

Identification

• Journal: Scientific Data
• Year: 2025
• Date: 2025-12-06
• Authors: Stéphanie Musy, Horst Dresmann, Yama Tomonaga, Yuji Sano, Oliver S. Schilling
• DOI: 10.1038/s41597-025-06380-z

Research Groups

• Hydrogeology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
• Applied and Environmental Geology, Hydrogeology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
• Entracers GmbH, Dübendorf, Switzerland
• Center for Advanced Marine Core Research, Kochi University, Kochi, Japan
• Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland

Short Summary

This study presents high-resolution 3D geological and integrated hydrological models for the complex Mt. Fuji watershed in Japan, along with a reproducible workflow for their construction in data-scarce volcanic regions. The models accurately simulate surface and subsurface hydrology, providing a crucial resource for integrated water resources management and disaster preparedness.

Objective

• To develop and openly provide high-resolution 3D geological and integrated hydrological models of the Mt. Fuji watershed, Japan, and a streamlined, reproducible workflow for their construction in geologically complex and data-limited volcanic environments, to support integrated water resources management and disaster preparedness.

Study Configuration

• Spatial Scale: Mt. Fuji watershed, Japan, covering approximately 1,650 square kilometers. The model extends vertically from 3,776 meters above sea level (ASL) to -1,100 meters ASL. Horizontal resolution for the geological model is 75 meters, and the finite element mesh has nodal spacing ranging from 185 meters to 750 meters.
• Temporal Scale: Simulations run for 3,000 years to achieve a quasi-steady state, utilizing present-day mean hydrometeorological forcings.

Methodology and Data

• Models used:
  • Integrated Surface-Subsurface Hydrological Simulator: HydroGeoSphere (HGS)
  • 3D Geological Modeling Software: Aspen SKUA (alternatively GemPy)
  • Numerical Mesh Generation Software: AlgoMesh (alternatively Gmsh)
  • Geographic Information System (GIS) Software: QGIS (alternatively ArcGIS Pro)
  • Visualization and Processing Software: Tecplot 360 (alternatively ParaView)
• Data sources:
  • Digital Elevation Model (DEM): ASTER Global Digital Elevation Model (GDEM Version 3, 30 m resolution), GEBCO_2024 bathymetric data, Japan Geospatial Information Authority lake bathymetry.
  • Hydrological Network: National river and lake maps (1:25,000 scale).
  • Hydrofacies Boundary Surfaces: Japan National Water Cycle Model (NHM) hydrofacies (500 m x 500 m resolution), geological map of Fuji Volcano, localized hydrogeological studies (contour lines, cross-sections), borehole logs.
  • Faults: Active Fault Database of Japan.
  • Land-use and Land-cover (LULC): 2022 High-Resolution Land-Use and Land-Cover Map of Japan (JAXA/EORC).
  • Verification Data: Independent borehole data, mean groundwater heads from the Water Environment Map of Mt. Fuji platform.

Main Results

• A high-resolution 3D geological model of the Mt. Fuji watershed was successfully constructed, delineating seven hydrofacies and incorporating the Fujikawa-Kako Fault Zone (FKFZ).
• An integrated surface-subsurface hydrological model (ISSHM) was developed using HydroGeoSphere, featuring a 2D finite element mesh with 24,800 nodes and 49,044 triangular elements, expanded into 40 vertical layers.
• The model accurately reproduces the extent and depths of the Fuji Five Lakes, with simulated maximum lake depths closely matching reported annual averages (e.g., Lake Motosu simulated at 130 m versus observed at 120 m).
• Simulated quasi-steady state hydraulic heads demonstrate excellent agreement with observed heads in the southern catchment and satisfactory agreement in the more complex northern mountainous areas.
• A reproducible workflow for constructing 3D geological and integrated hydrological models in geologically complex, data-scarce volcanic regions was established, significantly reducing model development time.
• The generated dataset, including 3D hydrofacies surfaces, numerical mesh files, and input configurations, is openly accessible, fostering further research in groundwater assessment, model calibration, climate impact studies, and hazard mitigation.
• Sensitivity analyses highlighted the critical importance of incorporating depth-dependent hydraulic conductivity (e.g., K_s = 4.976 x 10^-5 m/s at surface, decreasing exponentially with depth) and reduced-permeability surface waterbed sediments (K = 10^-8 m/s) for achieving realistic hydrological behavior and numerical stability.

Contributions

• Presents the first comprehensive, catchment-wide numerical integrated hydrological model for the geologically complex and data-scarce Mt. Fuji watershed.
• Develops and validates a streamlined, reproducible workflow for constructing 3D geological and integrated hydrological models in volcanic environments, which is transferable to other data-limited regions.
• Integrates diverse geological datasets (borehole logs, geological maps, hydrofacies surfaces) to create a robust 3D geological model suitable for advanced integrated surface-subsurface hydrological simulations.
• Provides an openly accessible dataset, including 3D hydrofacies surfaces, numerical mesh files, and HydroGeoSphere input configurations, enhancing transparency, reusability, and broader adoption of high-resolution hydrological modeling.
• Demonstrates the critical role of depth-dependent hydraulic conductivity and surface waterbed resistance in achieving realistic hydrological simulations in complex volcanic systems.

Funding

• Swiss National Science Foundation (SNSF) (grant number 216926)
• Strategic Japanese-Swiss Science and Technology Programme (SJSSTP) jointly funded by SNSF and Japan Society for the Promotion of Science (JSPS) (grant number 214048)

Citation

@article{Musy2025Modeling,
  author = {Musy, Stéphanie and Dresmann, Horst and Tomonaga, Yama and Sano, Yuji and Schilling, Oliver S.},
  title = {Modeling a geologically complex volcanic watershed for integrated water resources management in Mt. Fuji, Japan},
  journal = {Scientific Data},
  year = {2025},
  doi = {10.1038/s41597-025-06380-z},
  url = {https://doi.org/10.1038/s41597-025-06380-z}
}