Yokohama hosts international workshop with Singapore and Tokyo on advanced sewerage systems

On April 30, the City of Yokohama welcomed a delegation from Singapore’s National Water Agency (PUB) for an international workshop in collaboration with the Tokyo Metropolitan Government.

This event marked the first joint workshop between the three organizations following the conclusion of the GTX memorandum in March 2026. The workshop served as an opportunity to explore future collaboration and share expertise in large-scale sewerage infrastructure and flood management.

One of the highlights of the visit was a tour of the Nippa Suehiro Trunk Sewer, a major underground facility designed to mitigate flooding. The system stretches approximately 20 kilometers, reaching depths of up to 70 meters, and has a storage capacity equivalent to about 970 school swimming pools. This impressive infrastructure plays a critical role in protecting urban areas from heavy rainfall.

Participants engaged in active discussions, particularly on the challenges of balancing cost-effectiveness and investment prioritization in flood control measures. The exchange of ideas highlighted the shared understanding that flood mitigation functions much like insurance, requiring careful planning and sustainable investment.

In the afternoon, a separate session with Yokohama’s Port and Harbor Bureau focused on coastal protection strategies, including measures that consider local ecosystems. The Singapore delegation showed strong interest in Yokohama’s approach to storm surge mitigation.

The workshop concluded with a reaffirmation of the importance of international cooperation. Through continued dialogue and knowledge sharing, Yokohama aims to contribute to sustainable urban water management on a global scale.