As climate change brings more intense and frequent downpours around the world, nearly every city and town needs to be ready for extreme rainfall events. Experience shows that existing city drainage networks are often inadequate to cope with short periods of intense rainfall. Outdated codes and regulations may stand in the way of adopting newer approaches, such as nature-based solutions—including green roofs, rain gardens and bioswales—and smart water management.

This paper puts forward 10 guiding principles for effective cloudburst and stormwater planning. Drawn from our experience developing and implementing rainfall strategies around the world, the principles are set out under three themes: comprehensive planning, effective engagement and robust funding.

WSP case studies bring these principles to life, demonstrating approaches to foster resilience and safeguard people, businesses and communities for the long term.