Approach for evaluating inundation risks in urban drainage systems.

Area of Science:

• Environmental Engineering
• Urban Hydrology
• Risk Assessment

Background:

• Urban inundation poses a significant and growing threat to cities worldwide.
• Accurate inundation risk evaluation is challenged by complex, high-dimensional relationships between urban catchment indices.
• Existing methods often struggle with the non-linear nature of these relationships.

Purpose of the Study:

• To develop and validate a novel approach for qualitative and quantitative assessment of inundation risks in urban drainage systems.
• To identify the primary driving factors contributing to urban inundation.
• To provide a framework for improved urban drainage system design and flood preparedness.

Main Methods:

• Utilized a stormwater management model integrated with projection pursuit, ordinary kriging, and K-means clustering.
• Selected seven key evaluation indices and calibrated a rainfall-runoff model with twenty events.
• Applied the approach to a residential district in Guangzhou, China, under various rainfall scenarios.

Main Results:

• Identified inundation duration, peak flow, and total flood volume as key drivers of risk.
• Quantified manhole inundation risks across different rainfall return periods (1- to 100-year events).
• Established a logarithmic model illustrating the relationship between rainfall intensity and inundation-affected areas.

Conclusions:

• The proposed method effectively assesses urban inundation risks without subjective bias.
• Risk levels and affected areas escalate with increasing rainfall return periods.
• The findings offer valuable guidance for enhancing urban drainage infrastructure and disaster preparedness.