Sponge cities in China are using ancient farming and water management methods to sustainably tackle the growing water crisis.
Global water demand is increasing as a result of factors like population growth, economic development and a shift in diet. In China, one of the world’s fastest growing economies, the vital resource is running out. and many of the country's 1.4 billion residents have limited or unevenly distributed access to water.
North China is particularly impacted as it suffers from water shortages throughout the year. Meanwhile in south China, it has sufficient quantities of water and experiences only seasonal scarcity. While 80 per cent of water is concentrated in south China, the north is the core of national development.
Something had to be done. To combat this growing issue, the country is creating “sponge cities”.
The sponge city initiative, which launched in 2015, invests in projects that focus on absorbing floodwater. Currently, sponge city designs are being explored in 30 cities, including Shanghai, Wuhan and Xiamen.
"More than ever, facing global climate change and destructive industrial technologies, we have to rethink the way we build our cities, the way we treat water and nature."
A sponge city is a nature-based solution which uses the landscape to retain water at its source, slow down water flow and clean it throughout the process.
The focus is to retain rainwater in urban areas by waterproofing the paved ground so that part of it evaporates and the rest is gradually drained. As well as proofing the roads and pavements, more trees are planted and smart buildings are constructed to adapt to the city's sponge. This means roofs are covered in grass for greater absorption of water and buildings are also painted in light colours to reflect more heat instead of absorbing it.
Professor Kongjian Yu is an ecological urban planner and landscape architect, a professor of landscape architecture at Peking University and the founder of the planning and design office Turenscape in Beijing.
Taking inspiration from international integrated urban water management strategies, including sustainable drainage systems seen in the UK and low-impact developments in the US, Yu designs sponge cities to control urban flooding, tackle water pollution and recycle rainwater.
“Though grey infrastructure of concrete, steel, pipes and pumps, can be necessary to solve urgent individual problems, it consumes huge amounts of concrete and energy, lacks resilience and often accumulates a higher risk of disaster. It breaks the connection between man and nature,” said Yu.
“More than ever, facing global climate change and destructive industrial technologies, we have to rethink the way we build our cities, the way we treat water and nature, and even the way we define civilisation.
“Sponge cities are inspired by the ancient wisdom of farming and water management that use simple tools to transform the global surface at a vast scale in a sustainable way.”