Some older Wuhan residents still talk about paddling across the city in their boats, traversing the 100-plus lakes that were once connected by a network of canals. This once-leisurely activity takes on different meaning today as citizens navigate some of the worst floods in decades. Hubei Province, where Wuhan is the capital, is among the 27 central and southern Chinese provinces affected by floods that have caused CNY 86 billion (USD $12.3 billion) in nationwide economic losses in June and July of this year. 

At the confluence of the Yangtze River and Han Rivers, Wuhan is particularly vulnerable to flood disasters. Rapid urban growth since the 1980s that filled in and shrank its natural lakes have reduced the city’s natural storage capacity for floodwaters. Hit by over 40 inches of rainfall since June and on red alert, Wuhan’s bustling streets have ground to a halt, congested with an odorous mixture of rain and sewage.

Annual summer floods that lead to sewer overflows are not uncommon in Chinese cities, but they have been growing in frequency and severity. Spurred by the last major flood in 1998 that killed 3,000 people and caused USD $24 billion in damages, China invested heavily in grey infrastructure projects by expanding wastewater treatment plants, pipes, reservoirs, and building projects such as the Three Gorges Dam to alleviate flood risks. Recent decisions to release floodgates and blow up dams reflect the growing recognition that dams are no match for the increasingly severe climate patterns of the future and highlight the need for climate resilience strategies like green stormwater infrastructure that offer sustainable, nature-based solutions to flood prevention.

A Spongy Solution: China’s National Pilot Policy

China’s State Council established the Sponge City Policy in 2015 to designate flood control and climate resilience as top priorities. The policy challenged 16 pilot cities, including Wuhan, to trap 70 percent of rainwater by covering 20 percent of their urban landscape with sponge-like green infrastructure by this year and scale up to 80 percent coverage by 2030. 

Since 2015, the Wuhan city government’s spongy projects include urban gardens, constructed wetlands, permeable pavements, and water channels for flood diversion. The Wuhan Garden Expo Park boasts 30-square kilometers of public green space that sustain 400 plant species with onsite rain gardens. Qingshan and Sixin—two pilot districts—have completed 389 projects that retrofitted 38.5 square kilometers with new green infrastructure. The newest Wulijie neighborhood has incorporated valleys and ponds into its architecture to collect and treat surface stormwater. These green innovations have saved Wuhan more than CNY 4 billion (USD $600 million) in avoided drainage system upgrades, and have simultaneously increased property values and resilience to future floods. Current extreme flooding has exposed the urgency of redoubling climate resilience efforts like these.

The Sponge City Program has sparked collaboration among local government bureaus, private sector companies, and international NGOs on development of projects. For example, WWF China facilitates partnerships among Wuhan officials who can coordinate their work with local River Chief Program and Ramsar Wetland City accreditation initiatives in a way that supports Sponge City goals. 

Overflowing Enthusiasm for Spongy Cities in the United States  

Northeastern cities in the United States, where combined sewers are predominantly located, are no strangers to the benefits of green infrastructure. When total sewer overflow nationwide peaked in 2001 at 1.46 trillion gallons, cities experienced widespread contamination of drinking water. In 2000, the U.S. Environmental Protection Agency’s Clean Watersheds Needs Report to Congress estimated that grey infrastructure projects would cost $50.6 billion over 20 years to reduce national sewage overflows by 85 percent. While some federal grant funding is available, the U.S. 1994 Combined Sewer Overflow (CSO) Control Policy holds cities legally and financially accountable for the threats to water quality caused by overflow disasters and mandates their complete resolution by 2030.

Motivated by this financial burden, Washington, DC, New York City, and many other U.S. cities integrated green infrastructure with sewer improvement projects. Philadelphia sought to avoid $6.5 billion sewer upgrades entirely and in 2011 embarked on the most ambitious citywide green infrastructure program in the country. 

Before Philadelphia launched its Green City, Clean Waters Program, it released more than 13 billion gallons of raw combined sewage into its rivers annually—enough to fill almost 50 Empire State buildings. Now, the city will reduce its overflow volume by 85 percent over 25 years by weaving 10,000 “greened acres” into its urban landscape. Its success relies on strong community networks, public-private partnerships, and robust government grants. Programs like Rain Check and Soak It Up Adoption provide homeowners and community organizations with the tools to install their own rain gardens and rain barrels, while financial incentives encourage industrial properties, universities, and churches across the city to adopt green “spongy” infrastructure. Within the first five years, the program reduced annual sewer overflow volume by 1.71 billion gallons and contributed $4 billion in economic impact to the city.

Many U.S. cities incorporate green stormwater infrastructure into small community projects. The city of Royal Oak, Michigan is transforming its unused Normandy Oaks golf course into a multipurpose public space for schools and sports with green infrastructure additions. In an interview with the author, Royal Oak Energy and Sustainability Manager, Julie Lyons Bricker, emphasized that throughout the process, the city built partnerships with the school system, youth soccer club, and watershed association. A diverse mix of vegetation will offer many different green spaces to the community, while bioswales and detention ponds will increase stormwater storage capacity to 680,000 gallons and provide irrigation to soccer fields.

Small cities seeking to scale up their green stormwater efforts often face funding constraints. Amy Kay, the Clean Water Manager in Davenport, Iowa noted in an interview with the author that while green infrastructure funding is allocated through city stormwater and clean water fees, in practice these projects often lose out against competing priorities. Kay explained that without a unified regional or national green stormwater plan, local engineers and planners in small cities are left to incorporate green stormwater infrastructure into routine maintenance, wait for scarce funding opportunities, or forgo these projects altogether. In the summer of 2020, drops in municipal revenue from COVID-19 shutdowns is driving two dozen U.S. cities to renegotiate green infrastructure commitments, leaving the path unclear.

Is a Green Recovery Possible for Post-COVID Cash-Strapped and Flooded Wuhan?

No city is untouched by the COVID-19 crisis, least of all Wuhan, which at the start of 2020 was on track to reach its 2030 green stormwater goal. Now as funding concerns are exacerbated by the economic damages and disruptions caused by COVID-19 and unprecedented flooding, the future of green infrastructure investments is uncertain. Dr. Ren Wenwei, Water Practice Head for WWF China and a senior expert on the Lujiazui green finance committee in Shanghai, says stormwater investments in China will only stay afloat through the development of public-private partnerships with industry leaders and green loans from private banks.

Chinese meteorologists maintain that climate change is increasing and intensifying the rainstorms that are now flooding China. It is apparent that the impermeable urban landscapes of today cannot withstand the climate events of tomorrow. Like its U.S. counterparts, Wuhan has seen that green stormwater infrastructure is a powerful climate resilience strategy with extensive benefits to local economies and communities. The recent launch of China’s National Green Development Fund for investment in green development of the Yangtze river region represents a promising step towards green recovery. Economic revival from the COVID-19 pandemic and recent floods presents an opportunity for both China and the U.S. to double down on investments in green urban infrastructure and to make the recovery a springboard, not a roadblock, to a more resilient future.

Special thanks to Julie Lyons Bricker, Amy Kay, and Ren Wenwei.