Turku City, Finland

Site area: 27m2
Watershed area: 500m2

Spatial planning context:

In Turku the pilot area is situated near heavily trafficked streets alongside green space. The catchment area consists of the road area and mainly drains via stormwater pipelines. The pilot catchment is part of the watershed area of Kuninkoja, which is one of the biggest urban streams in Turku. Kuninkoja serves as an important habitat for many species and has recreational value for citizens bringing more greenery to the grey infrastructure..

Site-specific stormwater challenge:

Watershed area of the pilot site consists entirely of heavily trafficked streets. In previous studies, water quality issues such as high loads of suspended solids and phosphorus have been observed during the monitoring periods. Also, the water level in Kuninkoja rises quickly during the rain events due to the amount of impervious surfaces in the catchment area.

Site-specific stormwater solution:

The pilot area is situated near the end of the stormwater pipeline. A connection from the existing stormwater pipe will guide the flow into a bioretention basin through a sample well equipped with a real-time sensor for measuring water quantity. Filter media and plants are used for the treatment processes and the flow will be discharged via sample well, enabling water samples before and after the treatment.