Preparing for seawater floods

In Helsinki, the decrease of the sea level due to land uplift has stopped , and in the future, the sea level will rise even higher in the coastal area of Helsinki. The extent of the sea level rise depends on the rise in the level of the oceans, but the land uplift still balances out the rise. According to the average scenario, the sea level in Helsinki is estimated to rise by about 30–40 centimetres by the end of this century. The sea level rise will not end here, but due to global warming, the sea level will rise for at least hundreds of years.​

The lowest construction altitude in the new areas of Helsinki is at least 2.80 meters above sea level and is determined by the flood altitude. In addition, the effect of waves in different areas is also taken into account. The Safe Building Heights on the shores of Helsinki (2020) guide is used to determine these.​

Helsinki has examined the rise of the sea level and preparedness for it. The Helsinki Flood Strategy (2010) contains a set of flood protection measures that have been implemented to protect flood-prone areas. The Helsinki-Espoo coastal flood risk management plan (2021) presents objectives for sea flood preparedness. The city must plan and implement concrete technical solutions for individual sites.

Meri etualalla, taustalla Helsingin tuomiokirkko ja muita rakennuksia

The city has established a flood working group, which started its work in June 2023. The flood working group coordinates the city’s flood protection and makes preparations for flood management. In the event of a flood, the rescue services manage the operations.​​