Yuan et al. (2025) Critical Rainfall of Torrential Floods Induced by Heavy Precipitation Based on the FloodArea Model: A Case of Luba River, China

Identification

• Journal: Lecture notes in civil engineering
• Year: 2025
• Date: 2025-12-10
• Authors: Meng Yuan, Xiaojun Guo, Yao Huang, Jie Guo
• DOI: 10.1007/978-981-95-2169-2_5

Research Groups

• Sichuan Rural Economic Information Center, Chengdu, China
• Key Laboratory of Sichuan Province for Heavy Rain and Drought Flood Disasters in Plateaus and Basins, Chengdu, China
• Institute of Mountain Hazards and Environment, CAS, Chengdu, China
• Sichuan Meteorological Service Center, Chengdu, China

Short Summary

This study addresses the challenge of calculating critical rainfall for torrential floods in data-scarce mountainous small watersheds by employing the FloodArea hydrodynamic model. It successfully simulates a significant flood event in the Luba River Basin, validating the model's effectiveness and deriving critical rainfall thresholds for various flood risk levels to aid disaster prevention.

Objective

• To simulate and reproduce precipitation-induced flash flood inundation in mountainous small watersheds lacking hydrological data, specifically in the Luba River Basin.
• To calculate critical rainfall thresholds for different risk levels of torrential floods, providing scientific insights for flood control and disaster reduction strategies in the region.

Study Configuration

• Spatial Scale: Luba River Basin, Tongjiang County, Sichuan Province, China, with an area of 103 km². Digital Elevation Model (DEM) data with a 30 m spatial resolution was used.
• Temporal Scale: Hourly precipitation data from September 2014, with simulations focusing on the period from 01:00 to 15:00 on September 9, 2014. Critical rainfall thresholds were determined based on cumulative area rainfall over an 8-hour assessment interval.

Methodology and Data

• Models used: FloodArea Hydrologic model (a two-dimensional unsteady hydrodynamic model developed by German Geomer, integrated into ArcGIS 10.1). The Rainstorm model within the FloodArea framework was utilized for dynamic flood evolution simulations.
• Data sources:
  • Meteorological data: Hourly rainfall measurements from regional automatic weather stations, provided by the Sichuan Provincial Meteorological Bureau.
  • Geographic information: Hydrological systems and populated areas, sourced from the National Basic Geographic Information Center.
  • Field survey data: Information on disaster impacts, including inundation depth and duration, geographical coordinates, and elevation, collected through direct measurements and interviews with local residents.
  • DEM data: ASTER GDEM V2 global elevation data with a 30 m spatial resolution, acquired from NASA’s TERRA Earth Observation Satellite and supplied by the Institute of Computing Technology at the Chinese Academy of Sciences.
  • Areal rainfall calculation: Thiessen polygon approach was adopted due to sparse meteorological stations.

Main Results

• The FloodArea model successfully simulated the flood inundation process in the Luba River Basin for the September 9, 2014 event.
• Simulation results showed good consistency with field investigation data; the maximum simulated inundation depth at the warning point (3.6719 m) was approximately 0.37 m lower than the measured depth (4.05 m), which was deemed an acceptable error.
• The maximum inundation depth at the warning point occurred around 13:00 PM, aligning temporally with field survey findings.
• Both cumulative precipitation and hourly rainfall intensity were found to significantly influence flood inundation dynamics in small watersheds.
• A strong correlation (coefficient > 0.9) was established between simulated water levels at warning points and accumulated rainfall over an 8-hour period.
• Critical area rainfall thresholds for four risk levels were calculated based on cumulative area rainfall, providing specific values for different cumulative periods (1 hour, 3 hours, 6 hours, 9 hours). For example, for overtopping levees (Level 1), the critical cumulative rainfall is 16.615 mm (1h), 27.539 mm (3h), 35.038 mm (6h), and 39.609 mm (9h).

Contributions

• Verified the applicability and reliability of the FloodArea model for analyzing storm-induced flash floods and studying rainfall-related flash flood risks in small mountainous basins with limited hydrological data.
• Developed a methodology to calculate critical rainfall thresholds for different flood risk levels in data-scarce regions, providing a valuable reference for flash flood disaster prevention and mitigation strategies.
• Successfully reproduced a significant historical flood event, demonstrating the model's capability to simulate real-world inundation processes and validate its performance against field observations.

Funding

• NSFC (42322703)
• Sichuan S&T project (2022JDJQ0008)
• Western Light of Young Scholars, CAS

Citation

@article{Yuan2025Critical,
  author = {Yuan, Meng and Guo, Xiaojun and Huang, Yao and Guo, Jie},
  title = {Critical Rainfall of Torrential Floods Induced by Heavy Precipitation Based on the FloodArea Model: A Case of Luba River, China},
  journal = {Lecture notes in civil engineering},
  year = {2025},
  doi = {10.1007/978-981-95-2169-2_5},
  url = {https://doi.org/10.1007/978-981-95-2169-2_5}
}