Bryndal et al. (2025) Effects of Severe Hydro-Meteorological Events on the Functioning of Mountain Environments in the Ochotnica Catchment (Outer Carpathians, Poland) and Recommendations for Adaptation Strategies

Identification

• Journal: Water
• Year: 2025
• Date: 2025-11-13
• Authors: Tomasz Bryndal, Krzysztof Buczek, Paweł Franczak, Marek Górnik, Rafał Kroczak, Karol Witkowski, Robert Faracik
• DOI: 10.3390/w17223244

Research Groups

• Institute of Biology and Earth Sciences, University of the National Education Commission, Krakow, Poland
• Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
• Faculty of Mathematical and Natural Sciences, University of Applied Sciences in Tarnow, Tarnow, Poland
• Independent Researcher, Krakow, Poland
• Institute of Geography and Spatial Planning, Polish Academy of Sciences, Krakow, Poland
• Institute of Law and Administration, University of the National Education Commission, Krakow, Poland

Short Summary

This study comprehensively evaluates the multi-year environmental and economic impacts of a severe flash flood event in the Ochotnica catchment (Outer Carpathians, Poland) and proposes adaptation strategies, emphasizing the critical role of Maximum Probable Flood (MPF) hazard zone delineation for effective flood risk management.

Objective

• To comprehensively evaluate the impact of severe hydro-meteorological events on the mountain environment of the Ochotnica catchment, considering both environmental and economic aspects, over several years.
• To discuss key elements related to flash flood management.
• To formulate recommendations for adaptation strategies for flash floods in mountain areas.

Study Configuration

• Spatial Scale: Ochotnica catchment (105.7 km²) in the Gorce Mountains, Outer Carpathians, Poland, including 23 sub-catchments ranging from 0.64 km² to 12.29 km².
• Temporal Scale: Analysis of a flash flood event on 18 July 2018, with a multi-year perspective including field investigations seven years after the event (in 2025). Meteorological data for 18 July 2018 (15:00–20:00 UTC).

Methodology and Data

• Models used:
  • Slope-area method for maximum flow calculations (Qmax).
  • Manning’s equation for open-channel flow velocity.
  • Rainfall Formula for p-probable flood estimation (regional equation for catchments up to 50 km²).
  • K index (Françou–Rodier index) for flood magnitude comparison.
  • Maximum Probable Flood (MPF) approach (proposed for hazard zone delineation, potentially using envelope curves for Qmax estimation).
• Data sources:
  • Synoptic map and daily commentary on synoptic situation (Institute of Meteorology and Water Management of the National Research Institute, IMGW-PIB).
  • Surface Rainfall Intensity (SRI) radar data (Brzuchania radar station, 10-min temporal resolution).
  • Telemetry-type rainfall stations.
  • Post-flood field investigations (highest flood-water stages, geodetic measurements of cross-sections, energy slope, field observations for roughness coefficient).
  • Commission for Flood Damage Inventory (CFDI) data (infrastructure damage descriptions, spatial references, estimated flood losses).
  • Field campaign seven years after the flood event (2025) for mid-term impact assessment.
  • NMT and BDOT10k from www.geoportal.gov.pl for study area mapping.
  • Hydrate flash flood data center (www.hydrate.tesaf.unipd.it) and existing literature for comparative Carpathian flood data.

Main Results

• A severe rainstorm on 18 July 2018, with daily rainfall up to 101.1 mm and peak intensity of 26.2 mm·h⁻¹, triggered a flash flood in the Ochotnica catchment.
• Maximum flows in the most affected sub-catchments ranged from 6.3 to 31.1 m³·s⁻¹, with unit maximum flows from 7.94 to 10.76 m³·s⁻¹·km⁻², corresponding to 0.5–0.1% probable floods. Flow velocities reached 1.5 to 4.6 m·s⁻¹.
• The flood caused significant geomorphological changes, including bed erosion (up to 1 m), accumulation bars, debris flows, and numerous shallow landslides. These changes were largely preserved seven years later in areas without infrastructure damage.
• Economic losses were estimated at approximately EUR 4.6 million, representing ~40% of the Ochotnica Górna district’s annual income, primarily affecting roads, bridges, culverts, sewerage networks, and residential infrastructure.

Contributions

• Provides a unique multi-year perspective on the environmental and economic impacts of a severe hydro-meteorological event, assessing the mid-term resilience of a mountain catchment.
• Identifies a critical gap in current flood hazard mapping by demonstrating that flash floods often exceed the 0.1% p-probable flow, which is typically not included in existing strategic documents.
• Proposes the Maximum Probable Flood (MPF) approach as a key methodology for delineating realistic flood hazard zones in mountain areas prone to flash floods.
• Offers practical, context-specific recommendations for adaptation strategies in mountain environments, focusing on resilient design for roads, bridges, culverts, and residential infrastructure based on MPF parameters.

Funding

• University of National Education Commission, Krakow, grant number WPBU/2024/03/00111.

Citation

@article{Bryndal2025Effects,
  author = {Bryndal, Tomasz and Buczek, Krzysztof and Franczak, Paweł and Górnik, Marek and Kroczak, Rafał and Witkowski, Karol and Faracik, Robert},
  title = {Effects of Severe Hydro-Meteorological Events on the Functioning of Mountain Environments in the Ochotnica Catchment (Outer Carpathians, Poland) and Recommendations for Adaptation Strategies},
  journal = {Water},
  year = {2025},
  doi = {10.3390/w17223244},
  url = {https://doi.org/10.3390/w17223244}
}