How Copenhagen’s Most Devastating Rain Storm Inspired Climate Adaptation and Reunited a Community
Copenhagen, Denmark. (Photo courtesy of the author.)
On the evening of an otherwise warm and comfortable June day in 2011, Copenhagen, Denmark, experienced a rare but intense natural disaster that would forever change its approach to climate resilience.
The storm descended quickly; unabating rain fell in droves and with purpose, thundering down streets and barging into stores and houses. It was relentless, consuming the city: cars floated down major roads, and basements filled with sewage. 150mm (6 inches) of rain fell in under two hours, costing 6.2 billion Danish kroner (almost 1 billion USD) in damage.
This 2011 natural disaster, known as a cloudburst, was supposed to occur only once every thousand years. Yet, Copenhagen experienced four severe rainstorms from 2008-2014, including two 100-year cloudbursts in 2010 and 2014. These storms are now a common threat looming over Denmark.
A precise weather model from the Danish Meteorological Institute (DMI) determined that climate change doubled the likelihood and intensity of this 1,000-year cloudburst. Copenhagen’s winter rainfall is also projected to increase by 25% by 2100, with the majority of rain coming in the form of cloudbursts in between long dry spells. More frequent flooding seriously threatens Copenhagen since it is also a low-lying city.
Denmark's next cloudburst, however, will be up against a more prepared community. The storm that caused great destruction also triggered efforts by Copenhagen to invest in and bolster climate adaptation, leading to Copenhagen’s first “climate-resilient neighborhood.”
With the initial intention of managing water, the neighborhood also reunited a community, showing how synergistic sustainable spaces are while also inspiring other cities worldwide.
A Wake-Up Call
The 2011 cloudburst, with the prospect of more to come, was a major concern for Copenhagen. Municipalities were forced to prepare for more frequent cloudbursts or risk billions more in damage and repairs.
Still, Danish municipalities were faced with a dilemma. The most obvious solution to the floods was to expand the city’s sewage capacity to take in more water without rupturing. But, that change would’ve required a disruptive process of digging up a majority of the city to install new and expensive pipes.
Instead, the municipality began developing aboveground solutions. This search would eventually spark the plans for Copenhagen’s first climate-resilient neighborhood.
Klimakvarter: The Surface Solution
Climate Resilient Neighborhood outlined in red, projects listed in green. Modified from Google Earth by the author.
The Climate Resilient Neighborhood, Klimakvarter in Danish, involved several projects to redesign pre-existing areas of Copenhagen so they could handle more water, preventing important buildings from flooding.
Klimakvarter is located in Østerbro, a typical Copenhagen suburb. The initial effort involved general water management and solar panel installations throughout the area. There were three larger projects that transformed specific spaces: Fremtidens Gårdhave (Future’s Garden in English), St. Kjelds Plads (St. Kjelds Square), and Tåsinge Plads (Tåsinge Square).
The three spaces were nothing remarkable prior to the project. All locations were dull, in rough shape, and added nothing to the greater community, according to the chair of the board of Tåsinge Square Gry Sand.
L-R: Future Gardens, St. Kjeld Square, and Tåsinge Plads before the renovation.
Future Gardens was an average flat courtyard with a few sparse trees and grass. Tåsinge Square, meanwhile, was a patch of grass between two adjoining roads. “One really rundown disgusting pizzeria” was the only business by Tåsinge Square, leaving residents out of luck for nearby food, said Sand.
Before the project, "the bunker [square] was only used for dogs to shit", added one resident in a 2014 interview about the redevelopment.
Kjelds Square, for its part, was “the dullest place on earth”, said Sand. Katja Kjar-Levins, a resident of Klimakvarter, recalled it as “all concrete,” with some asphalt composing a roundabout.
Befriending an Enemy
The three areas were transformed to successfully manage large amounts of stormwater to protect infrastructure from severe flooding caused by cloudbursts. The efforts, however, also had the positive benefit of repurposing flood water so it could be used for recreation or for watering inside gardens.
Future Gardens. (Images courtesy of the author.)
Future Gardens was transformed into a water retention area that could manage a 100 year Cloudburst. Concave concrete paths lead roof runoff from each nearby apartment to the lower-lying parts of the courtyard that function as a water basin. Planted trees purify the water, along with layered gravel underneath the grass and soil, to allow the water to percolate through. There is even moss and other plants on top of the bike sheds to manage even more water.
Part of St. Kjelds square. (Image courtesy of the author.)
St. Kjelds Square utilized what is known as the first flush method, which directs the first influx of runoff to the sewers, given it contains the most pollution from making first contact with the roads. The second flush, or second batch of water, is directed to the vegetated water basins for storage and purification via plants. The whole area has been transformed with patches of diverse vegetation to help store and purify water.
Plants in the basin of Tåsinge Square were carefully selected to be flood and salt tolerant, so they thrive even in high volumes of saline runoff. In other parts of the square, the plants were selected based on the soil type and sun availability to ensure they could survive for several years. Finished in 2015, the project to date features lush, thriving trees, shrubs, and grass.
Flood and saltwater tolerant plants in Tåsinge Square. (Photo courtesy of the author.)
The Klimakvarter areas go beyond storing water; they repurpose excess rainwater to areas in need. In Future Gardens, there are several spots where water congregates, so dogs can stop for a drink, and residents can fill watering cans for their personal gardens. In Tåsinge Square, there are big buttons children can see-saw on to release stored water to play with.
Future Gardens pools for watering plants (left), Tåsinge Square water play area (right). (Photos courtesy of the author..)
In all three areas, the retained water does not go to waste; it hydrates the plants within the area. St. Kjelds Square supports a wide variety of biodiversity, including 48 native tree species. Instead of fearing too much water, KlimaKvarter turned water into a friend.
The Power of the People
Klimakvarter became an important climate-adapted area, but it would not have survived the test of time if the community was not involved in the design and implementation process. When designing Future Gardens, a project trial was presented in the courtyard, welcoming residents and passersby to chat with them. In Tåsinge Square, they welcomed nearby residents for four days to discuss what they envisioned for the place. In both projects, they learned what people desired and adjusted their plans accordingly.
Sand recalled that St. Kjelds and Tåsinge Square took public consultation a step further, contacting residents and nearby businesses right away and involving them in the process for the entirety of the project. Several meetings were held with them to discuss designs for St. Kjelds Square, and their opinions and desires were directly incorporated into the project.
For Tåsinge Square, a board was formed, consisting of one member per each nearby residential building. The board has connections at the municipality and also with the head architects of the square, giving nearby residents a meaningful voice.
The board is still functioning today, so residents can communicate if they believe a change needs to happen or if they want to use the space for something, said Sand. For example, it was a resident's idea to have a flea market at Tåsinge Square, and now it happens twice a year, providing another opportunity for community connections.
Sand explained that because the nearby residents took part in designing Tåsinge Square, they now “feel responsible for it” and take care of it, even picking up nearby trash, for instance. Involving the local communities in the construction allowed these three projects to become more than just water management; they are now places for residents to interact, form relationships, and enjoy the outdoors.
The Tåsinge Square project also enticed several new businesses to the area. Nice coffee shops and bakeries are now right across the square. Couples, friends, and family sit with warm beverages in the outdoor seating or on the grass itself.
People enjoying Tåsinge Square. (Photo courtesy of the author.)
Two new mothers spent precious time reconnecting on a picnic table atop a hill in Tåsinge Square. When asked about the space, they exclaimed, “We love it!”
In Future Gardens, children play on the stepping stones in the basin whilst a family picnics under a tree, and a father teaches his child to ride a bike on the surrounding pavement.
St. Kjelds Square is now filled with runners, bikers, and parents taking their children out for a walk through the winding paths.
These three climate adaptation areas have transformed an urban ecosystem and reconnected communities. As the chair of the board put it, Klimakvartar “shouldn’t just be a place for the rain; it should also be for people.”
Inspiring Others
Tåsinge Square was the first ever climate-adapted area in Copenhagen, but now there are areas all over the city. The Climate Resilient Neighborhood has also inspired cities beyond Copenhagen, reaching as far as the U.S.
In 2016, the Danish companies that built Sankt Kjelds Square were invited to New York City - which experienced an extreme coastal flooding event in 2012 - to share climate solutions on how to better prepare for cloudbursts and severe storms.
In 2017, New York started a resilience planning study based on Copenhagen’s methods, devising solutions that would address water management while providing environmental, social, economic, and health benefits. The study was completed in 2019, outlining adaptation efforts that will shape the future of New York City.
The accomplishments of Klimakvarter are just the beginning. We have the knowledge and the means to create a new future where humans are able to live more sustainably and thrive in a changing climate. The question isn't can we adapt, but rather: will we choose to in time?
