Marchi et al. (2010) Characterisation of selected extreme flash floods in Europe and implications for flood risk management

Identification

• Journal: Journal of Hydrology
• Year: 2010
• Date: 2010-07-23
• Authors: Lorenzo Marchi, Marco Borga, Emanuele Preciso, Éric Gaumé
• DOI: 10.1016/j.jhydrol.2010.07.017

Research Groups

• CNR IRPI, Padova, Italy
• Department of Land and Agroforest Environment, University of Padova, Legnaro, Italy
• Laboratoire Central des Ponts et Chaussées, Bouguenais, France

Short Summary

This study characterizes 25 extreme flash floods across Europe using high-resolution hydrometeorological data, revealing regional differences in seasonality, runoff coefficients, and short lag times, with implications for improved flood risk management.

Objective

• To identify and analyze the hydrometeorological causative processes of selected extreme flash floods in Europe.
• To characterize flash floods in various morphoclimatic regions of Europe based on collected high-resolution data.
• To derive implications for flood risk management, including monitoring and forecasting.

Study Configuration

• Spatial Scale: 25 extreme flash floods across a geographical belt in Europe (western Mediterranean to Black Sea), covering 60 drainage basins ranging from 9.5 km² to 1856 km² in area.
• Temporal Scale: Analysis of specific extreme flash flood events; lag times mostly less than 6 hours.

Methodology and Data

• Models used: A hydrological model was used to check collected hydrometeorological data.
• Data sources: High-resolution hydrometeorological data collected and collated for each event; peak discharge data for over 50% of studied watersheds derived from post-flood surveys in ungauged streams.

Main Results

• Flash floods exhibit distinct seasonality: Mediterranean and Alpine–Mediterranean regions mostly in autumn, while inland Continental regions commonly occur in summer.
• Continental events generally have smaller spatial extent and duration compared to Mediterranean events, and the flash flood regime is more intense in the Mediterranean Region.
• Runoff coefficients are typically low (mean value: 0.35), with higher values observed in the Mediterranean region.
• Antecedent saturation conditions significantly impact event runoff coefficients, even for extreme events.
• Runoff response displays short lag times, mostly less than 6 hours.
• A characteristic mean velocity of the flash flood process (for basins less than 350 km²) is determined to be 3 m/s.

Contributions

• Compilation and analysis of a unique high-resolution hydrometeorological dataset for 25 extreme flash floods across Europe.
• Detailed characterization of flash flood properties (seasonality, runoff coefficients, lag times, process velocity) across different European morphoclimatic regions.
• Highlighting the critical role of post-flood surveys in building and extending flash flood databases and developing new hazard assessment methods.
• Emphasizing the importance of accounting for antecedent soil moisture in operational flash flood forecasting.
• Providing insights into the required time resolution and spatial density of monitoring networks for flash flood-generating storms.

Funding

• Not specified in the provided text.

Citation

@article{Marchi2010Characterisation,
  author = {Marchi, Lorenzo and Borga, Marco and Preciso, Emanuele and Gaumé, Éric},
  title = {Characterisation of selected extreme flash floods in Europe and implications for flood risk management},
  journal = {Journal of Hydrology},
  year = {2010},
  doi = {10.1016/j.jhydrol.2010.07.017},
  url = {https://doi.org/10.1016/j.jhydrol.2010.07.017}
}