The Enghaveparken Climate parken in Copenhagen now attracts both people and stormwater drainoff

The more than 90-year-old green oasis, Enghaveparken, in the Vesterbro district of Copenhagen has been transformed following an extensive renovation project. The park is now one of the largest climate change adaptation projects in the City of Copenhagen. The project to renovate Enghaveparken was a collaboration between the municipality, Områdefornyelsen Vesterbro (municipal district renewal initiative) and HOFOR – Greater Copenhagen Utility. Several foundations also contributed to the project, and residents in the area were invited to be a part of the project as well. Following the project, Enghaveparken can now retain 22,600 cubic meters of stormwater runoff, and normal rainfall channelled to the park can be reused. In addition, major upgrades have been made to Enghaveparken, so that the park now has improved facilities for play, recreation and nature experiences. All renovation and renewal work was carried out with respect for the park's original architectural characteristics.

• The new Enghaveparken was inaugurated in December 2019

  The Enghaveparken renovation project is the largest so far out of a total of 300 climate change adaptation projects to be completed in the City of Copenhagen before 2035. 

   

  The project was approved by the Water Division of the Danish Competition and Consumer Authority in 2014. HOFOR – Greater Copenhagen Utility was the contractor for the first part of the construction phase up to spring 2018. During this phase, an underground retention basin and associated piping were established in the park area and outside on an adjacent street.

   

  The City of Copenhagen was the contractor for the second construction phase up to December 2019. This phase involved climate change adaptation above ground of the 35,000-square-metre park, with flood protection and modification work.

  
  The technical installations for flood protection and reuse of rainwater have an expected lifetime of 100 years.

  

• Too much rainwater in too little space

  Copenhagen's population density is increasing, also in the Enghaveparken catchment area, and the extreme rainfall events of the future will be more frequent and more intense. Therefore, the residents of the district of Vesterbro need protection against flooding during cloudbursts. 

   

  The renovation of Enghaveparken is to address several challenges.

  
  As we will be witnessing more frequent and more intense cloudbursts in the future, the drainage system has to be relieved of some of its burden.

  
  Furthermore, Enghaveparken's catchment area, the Carlsberg City District, is under major development. As part of the development, massive investments are being made to establish rainwater collection and retention solutions in the Carlsberg City District.

   

  However, Enghaveparken will still have to cope with more stormwater runoff from the new city district.

  
  Finally, the historical Enghaveparken needed a "makeover", to attune it to the needs of its modern-day residents.

   

• Rainwater retained and reused

  Enghaveparken can now manage both normal rainfall and cloudburst events. Moreover, rainwater can now be reused, saving the municipality at least one million litres of clean drinking water a year.  

   

  Normal rainfall from rooftops in Enghaveparken's catchment area is led onwards to the park via a closed piping system. In the park's Rosegarden, five underground pipes, each measuring 100 metres, make up a 2,000-cubic-metre circular retention basin.

   

  
  From the closed, underground basin, the municipality can tap water for the city's road sweepers and for irrigating trees.

  
  The remainder of the rainwater collected is led to an area in the park where it is treated using soil filtering and UV treatment. Then, the water is clean enough to be led back up into the park for the children to splash and play in.

  
  The park's Multi Pitch is a place for everyday play, games and sports, or just "hanging out". The pitch is up to 3.5 metres deep and can retain stormwater runoff.

  
  The Rosegarden is a depressed rain garden. Along with the park's lake it can retain water in the event of intense cloudbursts.

  
  The Multi Pitch, the Rosegarden and the lake can together retain a total of
  5,200 cubic metres of water, corresponding to what would fall during a 10-year rain event.

  
  The park's terrain surface slopes one metre from west to east. The municipality has exploited the slope in the terrain by building a dike along the northern, eastern and southern edges of the park, so that the water can be retained behind the dike. It somewhat resembles a dustpan and serves its purpose during the most intense cloudbursts, when the underground basin, the Multi Pitch, the lake and the Rosegarden have all filled to the brim with rainwater.

  
  At all other times, the dike, which is one-metre high at its highest point, serves as a seating area for the park's visitors.

  
  In the event of a cloudburst, the gates in the dike are automatically closed and the park is filled with water. The dike solution can retain 14,500 cubic metres of water. The park is closed to the public when the dike retains cloudburst water.

  
  When the drainage system has capacity again, the rainwater retained in Enghaveparken is gradually drained away into the drainage system. When all the water has been emptied from Enghaveparken, the park is cleaned before it is reopened to the public.

   

  Enghaveparken's underground basin, the depressed areas and the dike can retain a total of 22,600 cubic metres of rainwater, corresponding to what would fall during a 100-year rainfall event.

  
  The park's potential to retain and reuse rainwater will not be fully realised for a couple of years, when more cloudburst projects have been established in the area.

• Comprehensive climate change adaptation

  In addition to reusing rainwater, Enghaveparken has been significantly improved for users of the park. It now has better spaces and facilities for play and recreation and more urban nature, with many new plants and trees. 

   

  The renovated Enghaveparken meets many more purposes than protecting the area against flooding during cloudbursts.

  
  It is a safer, more fun and more enjoyable park than before. Among other things, the park now has a splash park and a permanent outdoor roller-skating rink.

  
  Lights have been installed along the park's paths and the dike offers seating spaces.
  The municipality has sowed a total of 220,000 bulbous plants and 11,000 perennials divided between 55 different species. Moreover, 950 rose bushes have been planted, along with 83 new trees divided between ten different species.

  
  All of these, together, contribute to boosting the biodiversity of the area.

• The municipality and the water utility have each invested tens of millions of kroner in the project.

  Climate change adaptation of Enghaveparken is being financed partly over wastewater bills as a co-financed project. 

   

  The entire renovation of the park has cost just under DKK 120 million. Of this, just under DKK 23 million went to establish the underground pipework. HOFOR – Greater Copenhagen Utility paid for this part of the project.

  
  The City of Copenhagen financed the above-ground part of the climate change adaptation works with around DKK 54 million via the co-financing scheme. DKK 38 million went to renovate the park's interior. An additional DKK 10 million was spent on establishing the roller-skating rink.

  
  Realdania contributed almost DKK 5 million to reconstruct the famous Danish architect Arne Jacobsen's original pavilions by the entrance to the park. The A.P. Moller Foundation donated more than DKK 10 million to restore the buildings inside the park.

• The public was involved in the project from the very beginning. The project was carried out following a traditional project model.

  It began in 2012 as an ordinary renewal project costing DKK 7 million. However, after a cloudburst survey in 2013, the municipality turned the project into a large-scale climate change adaptation project. 

   

  It all began in 2012, when the municipal district renewal initiative Områdefornyelsen Vesterbro (now closed) was tasked with renewing Enghaveparken.
  
  However, an agreement between the government and Local Government Denmark in 2013, which stipulated that all municipalities have a climate change adaptation plan, meant that the project was expanded to include the establishment of flood protection. The project was pre-approved by the Water Division of the Danish Competition and Consumer Authority in 2014.

  
  Throughout the project period up to 2019, local residents were invited to take part in the project. Among other things, a working group of 50 local residents was very active, contributing ideas and helping identify needs.

  
  The municipality and HOFOR has had a common working group throughout the period.

• Important to preserve the park's original architectural characteristics

  Enghaveparken was the famous Danish architect and designer Arne Jacobsen's first large project back in the 1920s. The park is listed, and it was therefore important to preserve its original architectural characteristics.  

   

  There have been no severe obstacles in connection with renovation of Enghaveparken.
  The only bump in the road was ensuring that the park's original architectural characteristics were preserved. This included preserving the original outline of trees.

  
  A complete rethinking of the entire park was therefore not an option. The flood protection works and the work to renovate the recreational elements had to be done with respect for the original characteristics of the park.

  
  However, the City of Copenhagen managed to turn these obstacles into a lever for rethinking the park under the given conditions. The project is a success, and the park has been well received by local residents.