Urban flood risk warning under rapid urbanization.

Area of Science:

• Hydrology
• Urban Planning
• Environmental Science

Background:

• Rapid urbanization in China significantly increases urban flood risks and associated losses.
• Urban flooding poses health risks, including epidemic diseases and water pollution.
• Effective non-engineering flood risk management, such as warning systems, is crucial for highly urbanized areas.

Purpose of the Study:

• To propose a novel urban flood risk warning method tailored for rapidly urbanizing Chinese cities.
• To develop an urban flood forecasting model to generate an urban flood inundation index for risk assessment.
• To validate the proposed method using a case study in Dongguan City.

Main Methods:

• An urban flood forecasting model with five modules: drainage system and grid dividing, precipitation assimilation, runoff production, and surface runoff routing (using 1D and 2D shallow water equations).
• A DPSIR (Driving force, Pressure, State, Impact, Response) model-based multiple index fuzzy evaluation warning method (DMFEW).
• Fuzzy comprehensive evaluation using linear fuzzy subjection functions to determine flood risk levels (4 levels).

Main Results:

• The urban flood forecasting model demonstrated very good performance in simulating two flood events in Dongguan City, with results comparable to observed water depths.
• The DMFEW method provided reasonable flood risk warning simulations based on the forecasting model's outputs.
• The study successfully validated the proposed integrated approach for urban flood risk management.

Conclusions:

• The developed urban flood forecasting model and the DMFEW method offer a viable solution for urban flood risk warning in rapidly urbanizing areas.
• The integrated approach effectively assesses flood risk by combining hydrological modeling with a comprehensive evaluation framework.
• This research provides a foundation for improving urban flood resilience and mitigating disaster losses in Chinese cities.