Tiếng Việt
When heavy rains pour down, many cities respond by building more embankments and drains. The Sponge City takes the opposite approach: embracing water and turning it into an urban asset. This concept, promoted by landscape architect Kongjian Yu, follows the principle of retain – slow – filter – adapt, relying on ecological infrastructure instead of merely pouring concrete.
Why a “sponge” is needed
- Floods, droughts, pollution, and the loss of wetlands are becoming increasingly severe.
- Grey infrastructure is easily overloaded, while it heats up cities and impoverishes ecosystems.
How a Sponge City works
- Retain water at the source through permeable surfaces, rain ponds, and underground tanks.
- Slow the flow with terraces, wetlands, and green corridors.
- Filter naturally with aquatic plants and wet soils.
- Design flexible spaces to live with seasonal water.
Immediate benefits
- Reduce local flooding, cool down urban areas, improve air and water quality.
- Increase biodiversity, create more parks, walkways, and riverfronts.
- Raise land value and improve community health.
Inspiring models
- Nanchang Fish Tail Park: a former ash dump turned into a floating forest, regulating nearly one million cubic meters of monsoon rainwater.
- Benjakitti Forest Park (Bangkok): an old industrial site transformed into a “sponge” in the city center, with four interconnected lakes and tree islands built from recycled materials.
Benjakitti Forest Park (Bangkok)
Why it suits Vietnamese cities
- Seasonal rainfall, rapid urbanization, and many lakes and ponds have been filled in.
- A solution is needed that goes beyond underground sewers and pumps.
A roadmap to start today
- Plan by watershed, preserve flood corridors and retention lakes.
- Standardize permeable surfaces for sidewalks, parking lots, and schoolyards.
- Apply green roofs and rain roofs to houses and buildings.
- Require each project to include “rain ponds – rain gardens – wetlands” proportional to its scale.
- Restore native trees and mangroves as “soft shields” against storms and floods.
Kongjian Yu reminds us to think like a water manager and act like a gardener: persistent, intelligent, and in harmony with nature. When solutions are connected across scales—from national and urban strategies to individual rooftops—a city that retains, slows, filters, and adapts will take shape: more sustainable, and more livable.