Preparing for heavy rainfall

1. Helsinki is currently investigating the stormwater flood risks in the city centre to prepare for various heavy rainfall scenarios in the future. In addition to flooded areas, the city also examines the potential damage costs and liabilities caused by floods. The work will be completed in spring 2024.​

2. In the next phase, solutions will be sought for the identified flood scenarios, primarily by using natural methods that are based on increasing the green structure (2024).​

3. The third stage of the work is to determine the level of preparedness for Helsinki, reflecting the ratio of the damage and solution costs in different heavy weather scenarios (2024–2025).​

4. Further work to strengthen preparedness for heavy rains throughout Helsinki is also being carried out in cooperation with HSY to develop a hydrological model that includes both a mixed and stormwater sewer system, as well as open sewers and ditches where water flows. Based on this work, it is possible to determine city-wide flood-prone areas and prepare contingency solutions for them primarily by natural means.