Green rainwater solution creates a new beautiful urban space in Copenhagen

Tåsinge Plads, a square in the district of Østerbro, Copenhagen, has been protected against heavy rainfalls. A total of 2,000 square metres of asphalt and a rather boring piece of lawn have been removed and transformed into a green oasis that can retain and collect rainwater from an area of road and rooftops half the size of a soccer field. So there is no longer the same risk that sewers will overflow in the event of powerful rainfall, because rainwater from the square and surrounding roofs will now drain into a series of rainwater basins or it will seep down into flower beds planted with plants that tolerate salty water. At the same time, residents in the area now have a new, exciting urban space; a meeting place for adults and a playground for children.

• Status: Tåsinge Plads is ready to take on new cloudbursts

  On 6 December 2014, a popular festival took place on Tåsinge Plads in Østerbro, Copenhagen. The festival marked the opening of the first climate-adapted urban space in Denmark which retains rainwater and provides relief for sewers during cloudbursts.

   

  The Klimakvarter (climate neighbourhood) project was launched in 2012. At that time, three large urban spaces in Østerbro, Copenhagen, were selected for climate-change adaptation efforts. The three urban spaces selected were Tåsinge Plads, Skt. Kjelds Plads (also a square) and Bryggervangen (a street).
  
  Tåsinge Plads is now the first of the three spaces to have been made climate-proof.
  Once actual construction had begun on Tåsinge Plads in May 2014, it took around six months to complete the new installation and plant the landscape so that it was ready for use in December the same year.
  
  The installation passed its test in September 2015 when a cloudburst brought 42 millimetres of rainwater in a mere 30 minutes.

• Background: Neighbourhood beautification coupled with climate protection

  A visionary contribution to a European urban space competition; a desire for beautification of the neighbourhood around Tåsinge Plads; and a powerful rainfall event paved the way for the first green cloudburst project in Copenhagen.

   

  In 2011, green rainwater solutions were not commonly thought about when planning urban renewal projects. Nonetheless, the architects Tredje Natur chose this approach in its project submitted to the Europan competition, which the City of Copenhagen had launched in connection with a neighbourhood beautification project in Østerbro; an urban area of Copenhagen known as the 'Climate neighbourhood'.
  
  Østerbro is a densely populated urban district where infiltration of rainwater is problematic due to a combination of high-density housing and many paved areas (asphalt, concrete, cobblestone).  The large cloudburst that same year stressed the need for action.
  
  The City of Copenhagen, the utilities company HOFOR and Områdefornyelsen Skt. Kjelds Kvarter (local urban renewal organisation) joined forces in the 'climate neighbourhood' project, for which Tredje Natur developed the vision.
  
  "When you're about to renew an urban space, why not climate-proof it as well? The City of Copenhagen took inspiration from Tredje Natur and seized the opportunity to address a challenge directly related to climate change, while at the same developing interesting and useful urban spaces," said Lene Nørgaard Rasmussen, project manager at HOFOR.

• The solution: Rainwater solution gives more urban green space

  The technical installation on Tåsinge Plads can manage and retain a lot of the rainwater falling in and around the square. As much as 30 percent of the water that falls in the neighbourhood now no longer runs into the sewers, and it is no longer necessary to dig new sewers in the area.

   

  Rainwater from an area of 4,300 square metres is being retained and managed. This is an area which corresponds to the size of half a soccer field. The installation has a lifetime of around 50-75 years.
  
  The westernmost area of the new urban landscape rises above ground level and there is a sunny and grassy slope where people can play or sit and relax with a cup of coffee. From here, the area slopes down towards a green area slightly recessed below ground level to the east where the rainwater can collect.
  
  The salty water from the roads was a challenge, because the environmental authorities do not allow salty water from roads to seep into the groundwater. Therefore, water from the roads had to be separated from rainwater from the roofs.
  
  The solution chosen leads the salty water from the roads to a special area resembling an enormous, recessed flowerpot. The flowerpot has been planted with salt-resistant plants and was installed with a membrane at the bottom which retains the rainwater during extensive rainfall, thereby providing relief for the sewer system. From the 'flowerpot', the water is led via a stormwater discharge system into the harbour.
  
  The rainwater from other parts of the square is directed to a sunken green area from where it seeps down into the groundwater.
  Rainwater from the rooftops is collected in underground reservoirs. Children can pump up water from the reservoirs using springboards. The water runs out over a couple of sculptured water drops and from here, in small channels, it runs out into an pool for children to play in, before it is directed onward to the sunken 'rainforest' from where it seeps into the ground.

• Benefits and added value: Tåsinge Plads sets the standard

  The neighbourhood around Tåsinge Plads and Skt. Kjelds Plads has been designated as a 'climate neighbourhood' and serves as a showcase for climate-change adaptation in Copenhagen. The initiatives, methods and solutions that are being developed here will motivate others to carry out climate-change adaptation projects elsewhere in Copenhagen and in rest of the world.

   

  In the 'climate neighbourhood', other urban districts can find inspiration for green solutions at street level; solutions that do more than climate-proof the neighbourhood.
  
  The vision is to forge a new understanding of the city; one in which rainwater is no longer seen as a problem to be sent to sewers as quickly as possible, but rather as a resource that can be used to create new experiences in the city.
  
  The 'climate neighbourhood' has been included on the Sustainia100 2013 list of the 100 most innovative sustainable projects in the world.
  
  In May 2015, the climate-change adaptation project on Tåsinge Plads was awarded a prize in the 'Environment' category at the annual conference of Nordic capitals.

• Financing: Co-funded by a utilities company

  The utilities company HOFOR paid the construction costs required to manage the rainwater. These include both the alternative solutions above ground and the underground solutions.

   

  The investment budget for the combined beautification and climate-change adaptation project on Tåsinge Plads was DKK 16 million.
  
  The neighbourhood beautification project contributed DKK 8 million. The City of Copenhagen contributed DKK 4 million and HOFOR DKK 4 million. Furthermore, owners of properties around the square contributed funds for renovation of their own properties and pavements.
  
  The construction work was carried out by Anlægsgartner Malmos A/S. Initially, the City of Copenhagen paid for the capital expenditure and took out a loan for the project. HOFOR is financing the municipality's instalments and interest on the loan over 25 years
  
  The square has retained its status as a privately-owned common road. The costs of maintaining and operating roads and pavements are still being paid by the property owners, whereas the City of Copenhagen is responsible for maintenance of the planted landscape and the square itself. HOFOR is financing operation of the hydraulic installations, including the replacement of topsoil.

• The process and stakeholders: Political backing

  The 2011 cloudburst made it clear that action was required. The Skt. Kjelds district was designated by the City of Copenhagen as a special area of action for developing methods and technologies for climate-proofing Copenhagen.
  
  The design of the square was derived in close dialogue with the residents in the area.
  
  "There was a strong sentiment to preserve the local neighbourhood feeling of the square and allow space for flea market and a café, for example. Many people were afraid that the area would turn into a crowd puller, and a lot was done to prevent this," said Lene Nørgaard Rasmussen. She also explained how the residents are very pleased with the result and their new, green square.
  
  The project is anchored in the local urban renewal organisation Områdefornyelsen Skt. Kjelds Kvarter, and the City of Copenhagen is participating with HOFOR. The team behind the project was instrumental in the physical transformation of Tåsinge Plads to the Copenhagen's first climate-adapted urban space, and was composed of the following architectural firms, landscape architects, etc.: Malmos A/S, GHB Landskabsarkitekter, Orbicon, Via Trafik og Feld – Studio for digital crafts.

• Barriers: Legal problems slowed the process

  Tåsinge Plads is situated on a privately-owned common road and, legislatively, the City of Copenhagen could not just up and develop another man's property, so this problem had to be solved before work could proceed. As a result, the project was delayed by several months.

   

  The combined beautification and climate-change adaptation project had been anchored with the local urban renewal organisation Områdefornyelsen Skt. Kjelds Kvarter.
  
  The organisation, which is partially state-aid funded, operates under other terms than the City of Copenhagen and has had legal authority to run the project from the beginning.
  
  Tåsinge Plads, which is categorised as an unregistered, unnamed privately-owned common road area, will be entered in the land register in years to come so that the square can be transferred to the City of Copenhagen. This means that the municipality will be responsible for operation and maintenance of the square in the future.
  
  Initially, the concept was that the water from the roofs could be collected and used, for example for children to play with or for adults to clean their bikes.
  
  "However, the health inspector in Copenhagen is more strict than elsewhere in Denmark and therefore does not allow people to come into contact with water that has been stored for more than 24 hours, even if a UV filter has been installed so that the water pumped up is free from bacteria. That was somewhat unfortunate," Lene Nørgaard Rasmussen said.