Copenhagen: From Concrete Jungle to Sponge City 🌊

Photo by Nick Karvounis on Unsplash

Copenhagen, the vibrant capital of Denmark, is renowned for its design, cycling culture, and high quality of life. But beneath the charming canals and green spaces, a pressing challenge looms: managing increasingly intense rainfall due to climate change. Rather than relying solely on traditional infrastructure like pipes and sewers, Copenhagen is embracing nature-based solutions, transforming itself into a “sponge city.”

The sponge city concept, originating in China, focuses on absorbing and retaining rainwater where it falls, mimicking how nature manages water. This involves integrating nature-based solutions into the urban landscape to capture, filter, and slowly release stormwater to mitigate flooding.

“If you want to survive, you have to be spongy,” says Yu Kongjian, dean of Peking University’s College of Architecture and Landscape Architecture, and founder of Turenscape, one of China’s largest landscape architecture firms. “Trying to protect cities with hard, gray infrastructure made of concrete is doomed to fail.”

Copenhagen is a frontrunner in the spongey revolution, and its journey offers valuable lessons for cities worldwide grappling with similar climate-related challenges. My dear archipelago home city of New York, I’m looking at you!

One of the key elements of Copenhagen’s sponge city transformation is the creation of what’s known as green infrastructure. Parks and green spaces are being redesigned to function as rainwater retention basins during heavy downpours. These areas, often featuring sunken lawns and permeable surfaces, can temporarily store significant volumes of water, reducing the strain on the city’s human-made drainage system and reducing the risk of flooding. For example, Enghaveparken has been renovated to include a large underground reservoir capable of holding approximately 22,700 cubic meters of water. This dual-purpose space serves as a recreational area for residents while providing crucial stormwater management capacity.

Beyond parks, Copenhagen is incorporating blue infrastructure into its urban fabric, giving water a place to flow. The city’s numerous canals and harbors are being leveraged to manage excess water. Innovative solutions like floating wetlands and constructed ponds not only enhance biodiversity but also help to filter and retain stormwater. Furthermore, permeable pavements are being increasingly adopted in streets and public squares, allowing rainwater to seep into the ground rather than running off into drains. This reduces surface runoff and helps to replenish groundwater levels.

The driving force behind Copenhagen’s commitment to becoming a sponge city is its ambitious Cloudburst Management Plan, developed after a severe storm in 2011 caused widespread flooding. This comprehensive plan outlines a series of long-term projects aimed at making the city more resilient to extreme weather events. It emphasizes a collaborative approach involving the municipality, utility companies, businesses, and citizens in implementing nature-based solutions across the urban landscape.

The benefits of Copenhagen’s sponge city approach are manifold. Beyond reducing flood risk and alleviating pressure on drainage systems, these green and blue infrastructure initiatives enhance the city’s livability. They create more green spaces for recreation, improve air quality, support biodiversity, and even help to cool urban heat islands during hot summer months.

Copenhagen’s journey to becoming a sponge city is not without its challenges. Retrofitting existing urban areas with green and blue infrastructure requires careful planning, investment, and community engagement. However, the city’s proactive and integrated approach serves as an inspiring model for how other cities can adapt to the increasing impacts of climate change by working with nature, rather than against it. As extreme weather events become more frequent, the lessons learned in Copenhagen offer valuable insights for building more resilient and sustainable cities for the future.

You can read more about Copenhagen’s plans to manage climate change at https://urbandevelopmentcph.kk.dk/climate.