A Review of Urban Flood Risk Analysis Methods and the Impacts on Power Supply and Drainage Systems

Floods pose substantial risks to people, the environment, infrastructures, buildings, and other assets. With rapid urbanization and global warming, extreme urban floods are projected to occur more frequently and with greater intensity. As a result, conducting robust flood risk assessments and evaluating their potential consequences has become increasingly essential. Yet, methods for assessing flood damage to infrastructure remain underdeveloped. This paper reviews existing flood risk assessment methods for urban areas, with a focus on pluvial floods caused by intense rainfall and their impacts on power supply and drainage systems. Scenario-based simulation using hydrological, hydraulic, and hydrodynamic models is the most widely used approach to flood risk assessment. However, many assessment methods overlook uncertainty, limiting the reliability and verification of their results. Urban floods can severely disrupt power and drainage networks. Substations are particularly vulnerable, and repairing flood-damaged substations is both complex and costly. In contrast, physical failure of drainage pipes during floods is less common due to their low failure rates and long service lives. The primary challenge for urban drainage systems is insufficient capacity to accommodate the surge in water inflow during extreme rainfall events.