Liu et al. (2025) Risk assessment of rainstorm flood disasters in the China–Pakistan economic corridor

Identification

• Journal: Scientific Reports
• Year: 2025
• Date: 2025-10-09
• Authors: Mengting Liu, Xu Min, Xingdong Li
• DOI: 10.1038/s41598-025-19230-0

Research Groups

• School of Mathematics and Physics, Lanzhou Jiaotong University, China
• State Key Laboratory of Cryosphere Science and Frozen Soil Engineering, Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, China
• University of Chinese Academy of Science, China
• Gansu Center for Fundamental Research in Complex Systems Analysis and Control, Lanzhou Jiaotong University, China

Short Summary

This study developed a comprehensive flood risk assessment model for the China–Pakistan Economic Corridor (CPEC) from 1979 to 2024, revealing a significant expansion of middle- to high-risk zones in central plains and southern lowlands, primarily driven by extreme rainfall.

Objective

• To develop and apply a dynamic, multi-indicator framework (Hazard, Sensitivity, Vulnerability, Coping capacity - HSVC) combined with the AHP–Entropy method to assess the spatial and temporal evolution of rainstorm flood risk along the China–Pakistan Economic Corridor (CPEC) from 1979 to 2024.

Study Configuration

• Spatial Scale: The China–Pakistan Economic Corridor (CPEC), extending approximately 3,000 kilometers from Kashgar, China, to Gwadar Port, Pakistan, covering an area of about 1.044 x 10^6 square kilometers.
• Temporal Scale: 1979–2024, divided into two periods: P1 (1979–1999) and P2 (2000–2024).

Methodology and Data

• Models used:
  • Comprehensive flood risk assessment model based on the Hazard, Sensitivity, Vulnerability, and Coping capacity (HSVC) framework.
  • Analytic Hierarchy Process (AHP) and Entropy Weight Method (EWM) for combined indicator weighting.
  • Normalization (min-max scaling) for indicator values.
  • Natural breaks (Jenks) method for classifying risk levels.
• Data sources:
  • Hazard: ERA5-Land dataset (1979–2024) for maximum daily rainfall (Rx1day), maximum rainfall over three consecutive days (Rx3day), and consecutive wet days (CWD). Historical flood events from the Global active archive of large flood events (1985–2024).
  • Sensitivity: ASTER Global DEM for elevation and slope; HydroSHEDS v1 for drainage density; GRIP global roads database for road density.
  • Vulnerability: GPWv4 for population density (2000–2020) and vulnerable population ratio (1979–2024); ESA Urbanization Settlement Model Grid for urbanization index (1990, 2014); GHSL-BUILT for urban built-up area (1975–2020).
  • Coping capacity: ISIMIP2a GDP input data (v1.0) for regional Gross Domestic Product (GDP) levels (1979–2024); Global dataset of historical yields for major crops (1981–2015) for major crop production.
  • All datasets were resampled to a spatial resolution of 0.1° raster data.

Main Results

• High-risk areas for rainstorm floods are predominantly located in the central plains and southern lowlands of the CPEC, forming continuous bands, while low- and mid-low-risk zones are concentrated in the northern mountainous and transitional regions.
• Comparing the period 1979–1999 (P1) with 2000–2024 (P2), low- and mid-low-risk areas remained largely stable, but middle- to high-risk zones expanded significantly, indicating a gradual increase in overall flood risk along the corridor.
• Extreme rainfall is identified as the dominant driver of flood intensity and spatial distribution.
• Vulnerability increased from P1 to P2, primarily due to population growth, urban expansion, and land use intensification, particularly in rapidly growing urban centers along the Indus corridor.
• Coping capacity showed spatial disparities, with economically developed regions (e.g., Punjab Plain, northeastern Khyber Pakhtunkhwa) exhibiting stronger capacity, while low-capacity zones expanded into remote, less-developed areas.
• Model simulations demonstrated high agreement with historical flood records, which showed a sharp increase in major flood events from 17 in P1 to 45 in P2, mostly concentrated in high-risk provinces like Khyber Pakhtunkhwa, Sindh, and Punjab.

Contributions

• Developed a comprehensive, dynamic, and multi-indicator framework (HSVC with AHP–Entropy) for rainstorm flood risk assessment, providing a balanced integration of subjective criteria and data-driven evidence.
• Conducted a long-term (1979–2024) spatial and temporal evaluation of flood risk along the CPEC, addressing a gap in existing region-specific or cross-sectional analyses.
• Identified specific flood hotspots and elucidated the spatiotemporal evolution of flood risk, clarifying the roles of hazard, sensitivity, vulnerability, and coping capacity.
• Provided a scientific basis for targeted flood management, infrastructure reinforcement, and adaptive planning strategies in the CPEC corridor.

Funding

• China–Pakistan Joint Program of the Chinese Academy of Sciences (Grant No. 046GJHZ2023069MI)
• Program of the Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Chinese Academy of Sciences (Grant No. CSFSE-ZZ-2402)
• Foundation for Innovative Fundamental Research Group Project of Gansu Province (Grant No. 25JRRA805)

Citation

@article{Liu2025Risk,
  author = {Liu, Mengting and Min, Xu and Li, Xingdong},
  title = {Risk assessment of rainstorm flood disasters in the China–Pakistan economic corridor},
  journal = {Scientific Reports},
  year = {2025},
  doi = {10.1038/s41598-025-19230-0},
  url = {https://doi.org/10.1038/s41598-025-19230-0}
}