Urban Flood Control

City drainage systems are designed with varying capacities to handle stormwater runoff, usually based on factors like average rainfall, peak storm events, and urban development.

In many cities, drainage systems are engineered to manage stormwater volumes associated with a "design storm" event, such as a 10-year or 100-year storm, meaning an amount of rainfall that statistically occurs once every 10 or 100 years.

Typical capacities can range from handling a few cubic meters per second in smaller systems to tens or even hundreds of cubic meters per second in major urban areas with larger drainage networks.

For example, New York City's drainage system can manage around 1.75 billion gallons per day (about 6.6 million cubic meters) during heavy rains.