Promoting public transport, improving air quality or managing water effectively are some of the challenges of the cities of the future. Addressing the effects of global warming requires the adoption of sustainable urban planning strategies. In contrast to droughts, different areas of the planet are experiencing episodes of serious flooding that have a negative impact on the quality of available water. Luckily, there are nature-based solutions that can help large cities alleviate these problems.
A 'sponge city' is one that incorporates the water cycle into urban planning and uses different elements to retain it, slow down its flow and purify it after rainfall. It is a concept coined by urban planner, architect and researcher at Peking University, Kongjian Yu, in 2013 whose objective is to control urban flooding, reduce water pollution and recycle rainwater. Some cities in China have incorporated landscaping into their urban fabric with such success that it is a model already exported to other countries, such as the United States.
One of the tactics for creating sponge cities is to waterproof paved soil, from sidewalks to roads, so that part of it evaporates and the rest progressively drains. These new eco-cities also incorporate sustainable buildings, with vertical gardens and grass-covered roofs that achieve greater water reabsorption. Likewise, more trees are planted and large urban areas are set aside to become river parks that retain and drain water.
Although conventional water pipe and pump infrastructure may be necessary to urgently solve specific problems, they “consume enormous amounts of concrete and energy, lack resilience and accumulate a greater risk of disaster” —said the Konjian Yu himself in statements to Euronews. The inventor of this system is committed instead to recovering the connections between man and nature through landscaping with aspects that are inspired by the structures of traditional agriculture.
One of the most significant examples of sponge cities is found in the Qunli Stormwater Park in Harbin, northern China. This massive wetland collects, cleans and stores rainwater, while protecting a native natural habitat. In addition, wetlands and ecological corridors are green public spaces ideal for recreational use by citizens. Sponge cities are examples of more livable places, with sustainable urban planning and awareness of the problems of climate change.
Other examples of 'sponge cities' are Berlin, one of the European municipalities that has opted the most for this model. The German capital has been taking measures for more than a decade to increase urban density and free up space to create absorption layers, in addition to promoting vertical gardens and green roofs.
Likewise, Beira, in Mozambique, has incorporated this philosophy to rethink its urban transformation after the devastating passage of Cyclone Idai in 2019, and Jakarta, the capital of Indonesia, suffering from a serious subsidence problem, is leaving. to empty aquifers and rethink natural flows
