Yokohama Deploys Flood Infrastructure and Citizen Resilience to Tackle Climate Risk

Yokohama, Japan's second-largest city and one of its largest international ports, has built a multi-decade flood resilience programme that includes the Tsurumi River Multipurpose Retarding Basin, elevated road networks and community preparedness resources. The city of 3.7 million earned a place on CDP's A List for its transparency and climate action, anchored in infrastructure engineered for current and projected flood risk.

Yokohama has faced severe flooding since Typhoon Ida in 1958, which affected more than 20,000 households. Climate change is intensifying this risk, as demonstrated by Typhoon Hagibis in October 2019 during the Rugby World Cup, which required the deployment of 110,000 rescue workers. The Tsurumi River Retarding Basin stores storm water to reduce flood damage while also serving as an athletic field and green space for public recreation. The International Stadium Yokohama, built on stilts, can shelter 70,000 people with floodwater flowing beneath its foundations.

The city's climate action plan integrates physical infrastructure with civic engagement, requiring citizens to take an active role in local resilience. Yokohama has developed flood hazard maps for each of its 18 wards providing real-time rainfall and extreme weather alerts. Evacuation shelter locations are published online and in a pocket guide for residents, workers and visitors. The Retarding Basin Operation Centre, managed by the Keihin River Office of the Ministry of Land, Infrastructure, Transport and Tourism, has hosted approximately 420,000 visitors for public awareness events.

Yokohama's approach of integrating day-to-day infrastructure with flood-protection functions — including elevated main roads and multi-purpose basin facilities — reflects decades of adaptive urban planning. The city's model is increasingly relevant to other rapidly urbanising Asian coastal cities facing intensifying extreme weather under climate change. The Keihin River Office noted that the basin and surrounding infrastructure are engineered to withstand current and projected rainfall, providing a scalable template for climate adaptation in large port cities with similar hydrological challenges.

Key figure — 420,000 visitors to the Retarding Basin Operation Centre for flood awareness