Urban flood risk assessment using storm characteristic parameters sensitive to catchment-specific drainage system

Area of Science:

• Environmental Science
• Hydrology
• Urban Planning

Background:

• Urban floods are increasing, necessitating better risk assessment for drainage systems.
• Existing methods are challenged by the random nature of storm event rainfall patterns (hyetographs).

Purpose of the Study:

• To develop a more effective method for urban flood risk assessment.
• To correlate storm event characteristics with urban flood occurrences using hydraulic modeling.

Main Methods:

• Extracting characteristic parameters from hyetographs.
• Analyzing correlations between storm parameters and flood events via hydraulic simulations.
• Determining sensitive storm parameters and their thresholds for urban floods.
• Utilizing Frank Copula for joint probability distribution of sensitive parameters.
• Applying the method to the Chengzhong drainage system in Jiaxing, China.

Main Results:

• Identified mean rainfall intensity (I) and peak 30-min intensity (30-Rp) as critical storm characteristics for the studied system.
• Estimated the bivariate joint probability distribution of I and 30-Rp.
• Assessed annual urban flood risk by calculating the probability of exceeding critical rainfall thresholds.

Conclusions:

• The proposed method offers an efficient alternative for urban flood risk assessment.
• It is applicable to diverse urban catchments and drainage systems.
• Accurate risk assessment relies on identifying and analyzing sensitive rainfall parameters.