Sponges are well-known for their ability to absorb water. Berlin, Germany, is one of several big cities looking to utilize the same principle in its urban planning to help deal with climate impacts such as flash flooding and water shortages.
Sustainability Magazine reported on the turn to convert metropolitan areas into "sponge cities," explaining that most modern urban centers rely on materials like concrete and tarmac, which do not let water through easily and prevent it from being absorbed into the ground. This can lead to excess amounts of water entering drainage systems and flash flood risks.
However, companies like SUEZ and Arup are helping cities become "spongier" to alleviate these risks. They are using green infrastructure — such as the addition of parks, wetlands, and ponds, which can absorb excess water — along with more permeable surfaces instead of concrete. Meanwhile, the water that does make it into storm systems can be utilized later, thanks to underground storage facilities.
Berlin is one of the cities hopping on to this strategy and will have around 300,000 cubic meters of underground storage space for water by 2025.
"Every drop of water counts, and a sponge city is synonymous with the blue-green infrastructure transformation that we, and other regions in Germany, are developing and implementing for the next generation," Christoph Donner, Chairman of Berlin Water Company, told Sustainability Magazine.
Becoming a sponge city doesn't just conserve water and prevent the sometimes costly consequences of flooding — it can also help protect aquatic animals like fish. For instance, Astrid Hackenesch-Rump, a spokesperson for the Berlin Water Company, told Deutsche Welle that overflows in Berlin regularly lead to oxygen depletion in the waters, which kills fish.
Aside from these benefits, having more green spaces in communities can help improve citizens' mental health. For instance, one study found a link between long-term exposure to green spaces and reduced risk of anxiety and depression. Another study found that spending as little as 10 minutes in nature can help adults who are coping with mental illness.Â
Plus, more green spaces can help boost wildlife biodiversity. This can benefit humans in many ways — healthier pollinator populations support our food systems, for instance.
Other cities that are becoming "spongier" include Wuhan, China, and Rotterdam, the Netherlands.
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