Protecting the Archipelago Sea and Local Waters

Rainwater and meltwater in urban areas, known as stormwater, carry nutrients, pollutants and litter into waterways. Turku is increasingly investing in directing, treating and delaying stormwater before it reaches rivers, lakes and the sea, for example in courtyards, parks and streets.

In Kirstinpuisto stormwater is managed using various nature-based solutions. These rely on natural processes to guide and purify water. The city is also increasingly working to reduce stormwater loads from construction sites.

Find out more in the City of Turku’s guide to construction site water management 

Read more about stormwater

When a new area is being developed in Turku, town planners and developers make use of the so-called ‘blue-green factor’ in their planning.This tool helps ensure that plots contain sufficient vegetation, permeable surfaces and stormwater management solutions such as green roofs and rain gardens. The blue-green factor also helps the city prepare for flood risks..

Find out more about the blue-green factor in construction

The Kakolanmäki Wastewater Treatment Plant is a good example of a joint regional effort for the benefit of the Archipelago Sea. The plant treats wastewater from 14 municipalities. Since its introduction, phosphorus loads entering the Archipelago Sea through wastewater have fallen by approximately 70 per cent compared with the period before the plant began operation. Phosphorus contributes to eutrophication and, for example, harmful algal blooms.

Nutrient loading from agriculture is one of the main causes of eutrophication in the Baltic Sea, as soil and nutrients run off from fields into watercourses. Turku encourages farmers to adopt sustainable farming practices on the city’s leased fields. The lease agreements set out practices that improve the condition of the fields and help the soil retain water. Healthy soil also supports more productive harvests.