China's drainage problem needs urgent and innovative solutions. Flooding regularly plagues 641 of the 654 largest cities, sometimes with high death tolls. And a 1-meter (3.3-foot) rise in sea levels could displace as many as 23 million people, according to the World Bank. In response, teams across 30 municipalities are tackling a massive government-sponsored program to absorb the deluge and downpours.
The so-called sponge-city projects require teams in flood-prone cities to build infrastructure and green space that can soak up water. That includes everything from installing rain gardens to creating more areas with permeable pavement. Some projects have been completed, while many others are set to wrap up next year.
In Wuhan, for instance, teams have completed or are working on more than 200 projects. That includes a CNY1.3 billion initiative to overhaul the 3.8 square-kilometer (1.5-mile) Nanganqu Park to add rain gardens, grass swales and artificial ponds.
Lowering water levels is a high goal. After kicking off projects in 2015, the Chinese government set a target that, by 2020, 20 percent of urban land should be able to absorb at least 70 percent of rainwater. The second phase of projects, running through 2030, ups that goal so 80 percent of each city's land is able to absorb 70 percent of rainwater.
Teams have tailored projects to meet each city's unique architectural environment. In skyscraper-crowded Shanghai, for instance, teams are focused on building 400,000 square meters (4.3 million square feet) of rooftop gardens. It's a practical solution for the densely populated city, where there's little room for new ground-level green space or revamping existing roads. Such options could also take too much time and money.
Where projects have been finished, sponge cities are realizing benefits beyond flood control. “Sponge city infrastructure is beneficial because it is also changing the living environment, helping with pollution and creating a better quality of life in these areas,” WenMei Dubbelaar, director of water management, Arcadis China, told The Guardian.
But China will have to get creative to sustain sponge city efforts. After the first phase wraps up next year, the central government will no longer provide funding, which to this point has been roughly 15 to 20 percent of each project. The remaining costs have been split between local governments and the private sector. To plug the funding gap, cities and project teams must devise new streams, including using private-public partnerships (PPPs) with developers, landlords and investors, says Faith Chan, PhD, associate professor, school of geographical sciences, University of Nottingham, Ningbo, China.
“PPP is the way forward that can create a win-win strategy to benefit multiple stakeholders,” he says. “It will reduce taxpayers’ budget—and the residents and the public may be able to enjoy the sponge infrastructures and facilities.”
Ultimately, Dr. Chan says, the lack of central government funding could become a catalyst for change and innovation. “These challenges could turn out to be good opportunities for stakeholders to do sponge city projects better.”—CJ Waity
