Structured Coupling of Probability Loss Distributions: Assessing Joint Flood Risk in Multiple River Basins

Area of Science:

• Environmental Science
• Risk Management
• Hydrology

Background:

• Natural hazard events cause significant losses, necessitating detailed impact estimations.
• Interdependencies between regions are often overlooked in risk assessments, leading to underestimation of extreme event losses.

Purpose of the Study:

• To develop a methodology for incorporating regional interdependencies into natural hazard risk analysis.
• To avoid underestimation of extreme risk by coupling loss distributions using copulas.

Main Methods:

• Utilized copulas to model dependencies between regional losses.
• Analyzed maximum discharge data from river basins and stream networks.
• Proposed a minimax algorithm for selecting coupled basin pairs without requiring river structure data.

Main Results:

• Demonstrated that coupling loss distributions effectively incorporates dependencies and avoids risk underestimation.
• The proposed minimax algorithm successfully identifies coupled basins, mitigating underestimation without needing detailed river network data.

Conclusions:

• The copula-based methodology provides a robust framework for large-scale natural hazard risk assessment.
• The approach is adaptable for various countries and natural hazards, enhancing the reliability of risk management strategies.