Sponge Cities: Nature’s Answer to Urban Water Challenges

The need to manage and control water is one of the defining challenges of human civilization. One visionary landscape architect believes the key to sustained success is to use natural processes to create “sponge cities” that ingeniously integrate manmade infrastructure with the widespread use of wetlands, rain gardens and green belts.

By Eric Herman

Concrete has long been our default solution to controlling water. We build dams, dikes, levees, culverts, and channels—massive gray infrastructure designed to control, contain, and defy nature. But as floods intensify, droughts linger, and cities strain against the dual forces of population growth and climate change, this rigid system is showing its cracks. In fact, in many places, it’s failing—inevitably, predictably, and sometimes catastrophically.

Indeed, concrete may be the world’s most used construction material, but it does not last forever.

Enter Kongjian Yu, the Chinese landscape architect who has become the world’s leading voice in a new way of thinking about water management. His concept of the “sponge city” doesn’t seek to conquer water, but to live with it. Instead of funneling rainfall away as quickly as possible, sponge cities absorb it, filter it, store it, and release it back into the ecosystem in ways that are beneficial to both people and nature.

Yu’s ideas have already reshaped more than 200 cities in China and beyond. His work points to a future that is not only more resilient, but more beautiful.

The Problem with Gray Infrastructure

For more than a century, engineers approached water as something of an enemy. Rivers were straightened and forced into channels. Floodplains were drained and paved. Stormwater was captured in pipes and whisked underground. Dams and levees grew taller and stronger, each generation trying to outbuild the last – all in the name of controlling water.

Although this approach has led to a vast infrastructure upon which all society depends, gray infrastructure comes with consequences:

• Floods are worsened, not prevented. When water has no natural landscape to disperse into, its destructive power concentrates.
• Droughts become more severe. By forcing rainwater out of cities, we miss the chance to replenish groundwater and aquifers.
• Habitats vanish. Urban sprawl erases wetlands, riparian zones, and green corridors.
• Maintenance costs skyrocket. Concrete ages, cracks, and requires perpetual repair—an endless battle against entropy.

Yu argues that this reliance on gray infrastructure is doomed. “You cannot fight water and win,” he has said. “You must give it space, let it breathe, and let it flow.”

What is a Sponge City?

A sponge city is exactly what it sounds like: an urban environment designed to soak up water like a sponge.

Instead of sealed concrete surfaces, sponge cities incorporate green infrastructure that captures rain where it falls:

• Permeable pavements that let water seep into the soil below.
• Green roofs and walls that retain rain and reduce runoff.
• Constructed wetlands that filter pollutants while creating lush habitats.
• Restored rivers and floodplains that can expand and contract naturally with the seasons.
• Rain gardens and bioswales that slow, absorb, and cleanse stormwater.

Together, these systems turn a hard, impermeable city into a living landscape that stores water in wet seasons and releases it in dry ones—balancing the extremes that define modern climate challenges.

Here we’ll walk through some of Kongjian Yu’s most celebrated sponge city projects, focusing on their design specifics: how they function hydrologically and how they also create beauty, culture, and civic value.

Qunli Stormwater Park – Harbin, China (2011)

• Challenge: Harbin’s new urban expansion threatened to bury the last remaining wetland under development. The wetland was degraded and prone to flooding.
• Design: Yu and his team transformed the site into a 34-hectare “green sponge” that captures, filters, and stores stormwater.
  • Hydrology: A perimeter embankment catches and channels stormwater runoff from surrounding urban areas into the wetland interior.
  • Filtration: Native vegetation planted across the wetland naturally filters pollutants while stabilizing soils.
  • Paths + Access: A raised network of boardwalks and viewing platforms allows residents to experience the water cycle firsthand without damaging the wetland.
• Result: The park is both a civic space and a functioning piece of green infrastructure, holding back floods while recharging groundwater and creating wildlife habitat.

Yanweizhou Park – Jinhua, Zhejiang Province (2014)

• Challenge: Once a neglected floodplain at the confluence of three rivers, the site was subject to seasonal flooding that made development difficult.
• Design: Instead of resisting floods, Yu embraced them.
  • Terraced Floodplain: The landscape is shaped into a series of planted terraces that gradually absorb and slow floodwaters. Each terrace is planted with flood-adapted native vegetation.
  • Pedestrian Bridge: A 700-meter serpentine footbridge winds through the park, giving residents direct access to river views while floating gracefully above flood levels.
  • Event Space: The park doubles as a cultural hub, with open lawns and amphitheater-like spaces that remain usable in dry months but flood safely during rainy seasons.
• Result: The project transformed a “wasted” river confluence into a resilient, biodiverse, and civic centerpiece for the city.

Houtan Park – Shanghai Expo Site (2010)

• Challenge: A polluted industrial brownfield along the Huangpu River needed to be remediated for the 2010 World Expo.
• Design: Yu designed a narrow (1.7 km long) riverside park that doubles as a water-treatment system.
  • Constructed Wetlands: A stepped system of wetlands filters polluted river water. By the time it exits the park, water quality meets standards for irrigation and recreation.
  • Productive Landscape: Edible plants like rice and other crops were incorporated, showcasing a working landscape within the city.
  • Riverbank Stabilization: Soft-edge terraces replace hard concrete embankments, allowing for habitat restoration and flood mitigation.
• Result: The park cleans 2,400 cubic meters of polluted river water daily, while also serving as a lush, walkable green corridor.

Liupanshui Minghu Wetland Park – Guizhou Province (2012)

• Challenge: Severe flooding and water pollution plagued the mining town of Liupanshui.
• Design: Yu restored the degraded river and wetland system by:
  • Retrofitting a Reservoir: The project redesigned the existing flood-control dam and reservoir to integrate with wetlands.
  • Floating Vegetation Mats: These filter pollutants and provide new habitats for fish and birds.
  • Public Amenities: Paths, boardwalks, and cultural features were woven through the wetland, creating an accessible urban oasis.
• Result: The project drastically improved water quality while giving the city a recreational and ecological landmark.

Nanchang Fish Tail Park – Jiangxi Province (2019)

• Challenge: Rapid urbanization and a degraded lakefront with seasonal flooding.
• Design: Yu’s approach: sculpt a lakefront into a sponge-like landscape.
  • Water Storage Basins: Interconnected ponds and wetlands absorb storm surges and store rainwater.
  • Native Planting: Flood-tolerant reeds, willows, and grasses provide seasonal beauty and filtration.
  • Walkways: A system of causeways and islands allows people to wander directly through wetland habitats.
• Result: What was once an eroded, flood-prone edge became a lush “amphibious park” celebrated for its ecology and aesthetics.

Shared Design Principles Across Yu’s Projects

1. Work with water, not against it. Floodplains, wetlands, and riverbanks are given space to expand and contract naturally.
2. Multi-functionality. Parks double as stormwater systems, wetlands double as civic spaces.
3. Native planting palettes. Resilient species adapted to local hydrology reduce maintenance while restoring biodiversity.
4. Visible infrastructure. Unlike hidden pipes and culverts, Yu makes the water cycle visible—teaching residents to value it.
5. Ecology + beauty. These places are not only functional—they are places of joy, wonder, and pride.

The Science and Art of Absorption

At its core, the sponge city is a simple hydrological idea: mimic the natural water cycle. But Yu elevates it beyond engineering into an art form.

In city after city, his projects restore ecological function while adding new layers of civic beauty. Parks double as floodplains. Playgrounds are designed to collect rainwater. Walkways wind through wetlands that manage storm surges while giving residents access to wildlife.

These are not hidden systems. Yu insists that water infrastructure should be visible, tangible, and celebrated. By blending public space with ecological function, he reconnects people with the rhythms of nature that cities have long ignored.

The benefits of sponge cities ripple outward:

• Public health: Cleaner water, fresher air, and greener spaces reduce urban heat and improve quality of life.
• Resilience: Cities are better protected from catastrophic floods and prolonged droughts.
• Biodiversity: Habitats for birds, fish, and insects flourish where once there was only pavement.
• Economy: Green infrastructure is often cheaper to build and maintain than gray, especially when long-term costs are considered.
• Culture: Sponge cities offer residents new connections to water, embedding rivers, ponds, and wetlands into daily life.

In China, where rapid urbanization often meant paving over natural systems, the sponge city model has been transformative. Cities like Wuhan, Shenzhen, and Beijing are rethinking development itself around Yu’s principles.

A Global Vision

While rooted in China, the sponge city concept is global in scope. From Rotterdam to Los Angeles, landscape architects and city planners are reexamining how they design with water. The lesson is universal: climate change makes old approaches obsolete, and adaptation requires a partnership with nature.

This doesn’t mean abandoning all concrete. Dams, reservoirs, and levees still have roles to play. But the future lies in hybrid systems where green and gray work together—where wetlands complement storm drains, and parks complement pumping stations.

Is the sponge city the wave of the future? It very well could be. As Yu says, “We must design with nature, or nature will design for us.”

For the watershaper, the lesson is clear. Whether working on pools, fountains, urban landscapes, or waterfronts, water design is no longer just about control—it’s about collaboration. The sponge city represents the most profound rethinking of water in urban life since the advent of modern plumbing.

Who knew that the answer to some of our greatest challenges could be as simple—and as profound—as learning how to be a sponge?

Opening image by Weiming Xie | Shutterstock, second and third, image by Dream Architects | Shutterstock, bottom image by Luciano Santandrea.