SDG 6, Clean water and sanitation, is one of the goals that Helsinki has achieved to a large extent. In Helsinki, clean drinking water and efficient wastewater management are available to everyone. In addition to this, wastewater treatment is world-class. SDG 14, Life below water, is particularly related to the Baltic Sea in Helsinki. It is one of the most sensitive and polluted seas in the world and particularly affected by eutrophication.
Helsinki’s water areas comprise large sea areas and freshwater areas, which include the Vantaa River, streams, ditches, ponds and springs. Helsinki’s archipelago of 300 islands stretches from the sheltered inner archipelago to the open sea. The water quality and the ecological status of small bodies of water and sea areas are affected by nutrients and harmful substances, litter, water traffic, treated wastewater and the condition of the open sea in the Gulf of Finland.
Even though the nutrient load in coastal waters has decreased in recent decades, thanks to developments such as advanced wastewater treatment technology and the centralisation of treatment plants, the coastal ecosystem has not yet recovered and eutrophication remains a key problem in the sea area off the coast of Helsinki. Over the long term, concentrations of total phosphorus and chlorophyll a, an indicator of the amount of algae, have continued to grow, and the total nitrogen concentrations fluctuate around the long-term average. The increase in the turbidity of surface waters has stopped at the 2010 level, and the turbidity of the waters near the seabed has decreased. However, the oxygen level of water near the seabed is continuing to decrease in Helsinki coastal waters, partially due to the rising average temperature of the coastal waters.
The eutrophication of the sea areas in Helsinki is caused by the nutrient load from the catchment area and the special characteristics of coastal waters and bays. Despite the decreased nutrient load, the phosphorus concentration in the middle and outer archipelagos has grown since the start of the 21st century. To reduce the load on the sea area, the Metropolitan Area must implement targeted actions in the local catchment areas.
The aim is to improve the state of the Baltic Sea not only through the development of the City’s own activities but also through the Baltic Sea Challenge. The Baltic Sea Challenge is a joint water protection effort of the cities of Helsinki and Turku, which includes a joint Baltic Sea Action Plan and a broad international network open to all. The Baltic Sea Challenge’s network members have voluntarily committed themselves to the protection of the Baltic Sea by drawing up their own Baltic Sea Action Plans.
One of the objectives of Helsinki’s blue network work in 2021–2022 was to provide information on water ecology in a more accessible format. In connection with the blue network work, new creek channels were discovered and creeks’ qualitative class and water body status were specified. As a measure to improve the condition of small bodies of water, a new guide was also prepared for the qualitative and quantitative treatment of construction site water.
- Wastewater treatment in the Helsinki region is world-class and covers the wastewater of 1.3 million residents.
- Comprehensive data on underwater biodiversity in the marine area of the Helsinki Metropolitan Area has been collected between 2021 and 2022, and underwater marine nature areas of local ecological significance have been identified.
- Coastal water monitoring is comprehensive and of high quality.
Areas for development:
- Monitoring of the status of currents and small bodies of water.
- Qualitative management of stormwater.
- Restoration of lost habitats.
- Control of human pressure.
- Establishment of underwater nature conservation areas.