Natural stormwater management, i.e., absorbing rainwater and slowing it down with the green structure at its source, is necessary for the prevention of heavy rainfall floods.
The green structure includes all kinds of small and large green areas, such as plantings, depressions, wetlands, rain gardens, forested areas and meadows. All that is green, trees in particular, absorb water and cool the air through evaporation. The green structure has many benefits: in addition to mitigating the effects of climate change, it offers recreational opportunities, improves the microclimate, supports diversity and increases comfort. The green structure is also able to purify stormwater by filtering impurities from it.
Various natural stormwater management systems have been built in Helsinki for both public and private areas. Two of them are presented here as examples:
– the sand filtration solution in Maunulanpuisto, and the
– Metsälä biochar filtration area,
both of which control storm water both quantitatively and qualitatively.