Rainwater installation disguised as a skateboard park

Last updated on December 3, 2015.

About he project

Rabalder Park in Roskilde is a living example of how rainwater installations can serve several purposes simultaneously.

Rabalder park

Skateboards, in-liners, scooters, BMX bikes; in recent years, an increasing number of Danish children and young people have taken to these 'sports on wheels'. Until recently, skateboarding enthusiasts have sent each other to abandoned and remote warehouses, car parks and other skate spots, as they are called, when they send tips on the internet about good asphalt and concrete surfaces in the city. In Denmark, there has been a shortage of skateparks as we know them from the US; the home of skateboarding.

However, now it seems that several Danish municipalities have realised that the skateboard trend is here to stay. The skateboard culture has developed from a passion for a small youth culture to a popular leisure activity for all families. Among other things, the City of Copenhagen has transformed the worn-out skatepark in Fælledparken into an internationally recognised skate facility. Other municipalities have since followed suit. Haderslev in Jutland, for example, is establishing a large StreetDome in the middle of the docks area.

Bowl, snake runs and picnics

In August 2012, Ida Auken, the Danish Minister for the Environment helped open the new Rabalder skatepark in Roskilde. The park is unique. The primary purpose of the park is actually not to provide concrete for the skaters' spins and tricks, but to divert surface and rainwater from the local motorway and from the new culture district, Musicon, which is located between the Roskilde Festival site and Roskilde city centre. In fact, Rabalder Park is a large installation to divert rainwater, disguised as a skateboard facility and a recreational area.

"The background for the new installation was that the rainwater was to be kept on the surface and used as a creative element. We had good experience with this from the Trekronersøen lake; another climate change adaptation project here in Roskilde. Moreover, we needed to find a solution that required a minimum of digging, because the area had previously been used as a waste disposal site and a concrete factory. This means that the soil contains large amounts of gas and waste down to seven metres," said Kirsten Toft, planning and project manager at the utility company Roskilde Forsyning.

The idea to combine the rainwater installation with an activity park for skateboarding arose from experience from Trekronersøen lake and from an architecture competition organised for the entire Musicon area.
Soil dug out during excavation for the construction work was utilised to create hills that establish recreational areas suitable for picnics. Space has also been made for a long and wide slide, sunken trampolines and hammocks. This has created a local gathering point in a brand new district out of a necessary technical unit.

The installation has been dimensioned for a 10-year rain event, and 'the Bowl' is the last of three basins that will fill up when it rains heavily for long periods. Photo: Victor B. Larsen.

The lake, the meadow and the bowl

The installation is 40,000 m². It consists of a 445-metre-long canal system, which flows into three retention basins in the southern part of the area. The canals are also called 'snake runs' named after the dried-up river beds, used by skaters for many years, and which 'snake' through the landscape. The retention basin itself could be a skate bowl.

The installation works as follows: the three basins, named Søen (the lake), Engen (the meadow) and Bowlen (the bowl) are filled one by one when it rains heavily and for long periods. When it rains heavily, the GBH Landscape Architects' sculptural rain steps lead down the water to Søen. Then the water can run across the Engen, which is located on the other side of the Bowl.

If it rains extremely hard and for a long period, the water from the canals will eventually fill up the Bowl.
 The rainwater can then be pumped up into the sewer system and then discharged into Roskilde Fjord. The recreational elements of the installation have meant that the installation has been dimensioned differently than normal. For example, the rainwater canal would usually have been smaller and straighter.

When the entire Musicon district is finished, expectations are that all three basins will only fill up every ten years. The lake basin has a daily water volume of about 1,000 m³, but the overall basin can hold at total of 23,000 m³ rainwater. The basins alone cover an area the size of a football field and can hold the same volume of water as 10 swimming pools.

Financing must be arranged from the start

Roskilde Forsyning is responsible for the technical part of the installation, while the Municipality of Roskilde is responsible for the recreational part.
"It's important that responsibilities and financing are allocated between the utility company and the municipality right from the beginning of a project of this size, not least when it comes to maintenance costs. We have followed the 'keep it simple' principle. This means that Roskilde Forsyning makes sure that the installation itself is working as intended and, for example, cleans up after extreme rain, whereas the Municipality of Roskilde is responsible for daily maintenance of the actual activity area," said Kirsten Toft.

The combined installation has had a total budget of DKK 35 million. Ultimately, this is about DKK 10 million more expensive than a rainwater installation alone would have cost. On the other hand, this figure is much lower than what it would cost to construct a similar park for recreational users alone. Kirsten Toft recommends investigating whether there are charitable foundations which could be interested in supporting similar projects. The Danish Foundation for Culture and Sports Facilities has supported the project with DKK 2.5 million. Other foundations which have supported the project include Roskilde Fonden and Nordea-fonden.
Rabalder Park opened on 30 August 2013, and has already won two awards: Bylandsprisen and Bæredygtig Beton Prisen.

According to the Magasin Tribune magazine, issued by the Danish Foundation for Culture and Sport Facilities, the Danish Minister for the Environment, Ida Auken, said during the opening of Rabalder Park:
"I'm so proud to live in a country where we are capable of making climate change as fun as this. We must learn to live with water in a new way, and Rabalder Park is a fantastic example of how to do this. Instead of a dull technical unit, the citizens of Roskilde now have the coolest skatepark in Denmark, and the area also has a cosy atmosphere with hammocks, barbecues and benches."

Map of Rabalder Parken. Drawing: GHB Landskabsarkitekter.

Facts about Rabalder Park

  • Total budget: DKK 35 mill.
  • Costs for added value: DKK 10 mill.
  • The total basin can contain 23,000 m³ rainwater.

Facilities

  • Lake with rainwater/retention basin
  • Meadow area/retention basin
  • Bowl/retention basin in concrete - 1000 m2 in total
  • Water canal in concrete - 110 metres
  • Water canal in asphalt - 335 metres
  • Ramp (2 m wide and 20 m long) in steel
  • Hammocks
  • Sunken trampolines
  • Three fitness points
  • Water steps with benches
  • Barbecue and seating
  • Miscellaneous steel bars for roller skates and skateboards

Contact

You are welcome to contact us at the email bellow if you know any good examples of climate adaptation projects:

klimatilpasning@mst.dk

More info