Helsinki / Helsingfors, Finland
City population: 1034274
Duration: 2012 – 2015
Implementation status: Completed
Scale: Micro-scale: District/neighbourhood level
Project area: 700 m2
Type of area: Public Greenspace Area
Last updated: October 2021

As part of the EU Life+ CITYWATER project (of 3 cities), a sustainable stormwater management solution based on biofiltration was implemented in Maunulanpuisto Park in Helsinki, in order to purify rainwater and meltwater and improve water quality in the Haaganpuro Brook. As the drainage area is heavily trafficked and paved with asphalt, high solid, nutrient and oil levels have occasionally been measured in the rainwater and meltwater entering the Haaganpuro brook. Such contamination is harmful to the fish stocks (e.g. trout) and other organisms in the brook. The biofiltration solution was the first of its kind in Helsinki. The solution also supported the City of Helsinki stormwater strategy, which aims at changing management towards sustainable solutions and states that stormwater should in first hand be infiltrated on spot, where it is created (ref. 1).


Nature-based solution

  • Blue infrastructure
  • Lakes/ponds
  • Green areas for water management
  • Sustainable urban drainage systems

Key challenges

  • Water management (SDG 6)
  • Stormwater and rainfall management and storage
  • Improvements to water quality
  • Green space, habitats and biodiversity (SDG 15)
  • Habitat and biodiversity conservation
  • Green space creation and/or management


Maintenance and management of urban nature, Monitoring of habitats and/or biodiversity, Management of rivers and other blue areas

Project objectives

1. CITYWATER aimed at improving the quality of local water that streams into the Haaganpuro Brook 2. The project also aimed at raising awareness about the problems of the Baltic Sea on a local level (Ref 1, 2, 3).

Implementation activities

- Create a biofiltration area where the water is pooled and vegetation given the time to bind nutrients and heavy metals. From here the water slowly permeates the filtrating sandy layers under the vegetation where harmful substances are absorbed, after which the purified water is fed into the Haaganpuro Brook (Ref 2). - Water quality improvement through sedimentation of suspended particles and microbiological activity and quantity control through retention (Ref. 3)

Biodiversity conservation or restoration-focused activities

Biodiversity conservation:

  • Protect and enhance urban habitats
  • Preserve and strengthen existing habitats and ecosystems
  • Reduce negative impacts and avoid the alteration/damage of ecosystem
  • Protect species
  • Undertake specific measures to protect species

Biodiversity restoration:

  • Rehabilitate and restore damaged or destroyed ecosystems
  • Restore species (native, endangered, or unspecified)

Main beneficiaries

  • Local government/Municipality


Management set-up

  • Government-led

Type of initiating organisation

  • Multilateral organisation
  • National government

Participatory approaches/ community involvement

  • Dissemination of information and education
  • Consultation (e.g. workshop, surveys)

Details on the roles of the organisations involved in the project

CITYWATER was a project of the Finnish Ministry of the Environment, but executed in close collaboration with the Baltic Sea Challenge network that extends beyond the Finnish border. The project was co-funded via the EU LIFE+ programme (ref 9). Funding provided by the LIFE+ Programme and the Finnish Ministry of the Environment. This solution was implemented in the framework of “CITYWATER- Benchmarking water protection in cities” project. The contract considering planning of the biofiltration technique was signed by the city of Helsinki with the Finnish Consulting Group (ref. 12)

Project implemented in response to ...

... an EU policy or strategy? Yes (The CITYWATER project particularly considers 1. the Water Framework Directive, 2. the Marine Strategy Directive, 3. the EU Baltic Sea Region Strategy, and 4. the HELCOM Baltic Sea Action Plan (Ref 3). It is not specified which specific directive/strategy influenced which specific project.)
... a national policy or strategy? Unknown
... a local policy or strategy? Yes (EU Life+ that also funded the CITYWATER project also funded the Helsinki Metropolitan Area Climate Change Adaptation Strategy that was published in 2012 (the same year as this intervention started) and emphasizes the importance of water management, especially in the face of intensified rainfall (Ref 10). )


Total cost

€500,000 - €2,000,000

Source(s) of funding

  • EU funds
  • Public national budget
  • Public local authority budget

Type of funding

  • Direct funding or subsidy

Non-financial contribution


Impacts and Monitoring

Environmental impacts

  • Water management and blue areas
  • Improved water quality
  • Improved stormwater management

Economic impacts

  • Attraction of business and investment

Socio-cultural impacts

  • Unknown

Type of reported impacts

Expected impacts, Achieved impacts

Presence of formal monitoring system


Presence of indicators used in reporting


Presence of monitoring/ evaluation reports


Availability of a web-based monitoring tool



Sedimentation and Biofiltration Area (2016)
Photographer: Kajsa Rosqvist (City of Helsinki/CITYWATER project), retrieved 08/15/2018