Green rainwater solution creates a new beautiful urban space in Copenhagen

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.

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 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 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.

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.