BANGKOK, October 13, 2026 : As extreme rainfall, sea-level rise and land subsidence place growing pressure on Southeast Asia’s major cities, urban resilience will increasingly depend on a fundamental shift in how planners think about water: not simply as something to drain, divert or keep out, but as part of the infrastructure itself.
That was the central argument put forward by Chloe Pottinger-Glass, Project Associate, UN Habitat, in a conversation with CarbonWire for the Climate Dialogues series on the sidelines of Bangkok Climate Action Week.
Speaking after a session on “amphibious cities” and living with water, Pottinger-Glass said one of the most compelling ideas discussed was the concept of the watershed as infrastructure. For cities such as Bangkok, that means looking beyond conventional flood-control systems and considering the entire natural catchment within which the city sits.
“Bangkok, as I was explaining, is a city that was built on a wetland,” she said. Despite sophisticated infrastructure, recent heavy rainfall still overwhelmed the city’s drainage capacity.
The watershed cannot be separated from the city
Pottinger-Glass described the watershed as the broader catchment through which water flows into and out of the city. In Bangkok’s case, that means the Chao Phraya Basin.
Her argument is that urban infrastructure cannot be planned independently of this wider natural system.
Bangkok already uses engineered systems and technology to prepare for heavy rainfall, including increasing retention capacity ahead of anticipated storms. But even with those measures, she said, extreme rainfall can exceed the system’s ability to cope.
Climate change is likely to make that challenge more difficult. Pottinger-Glass pointed to the combined effects of land subsidence, relative sea-level rise and increasingly unpredictable weather, arguing that these factors will make urban water management more complex over time.
“We can’t think of the city and its hard infrastructure and the broader natural system and its flows in which it sits as separate,” she said.
That principle is relevant far beyond Bangkok. Cities such as Jakarta, Ho Chi Minh City and Manila have similarly relied on drains, canals, pumps and embankments to manage water. But as climate risks intensify, the assumption that cities can simply engineer water out of the urban environment is becoming harder to sustain.
From keeping water out to living with it
Pottinger-Glass said there is already growing recognition across Southeast Asia that the old approach needs to evolve. Cities are increasingly experimenting with green infrastructure, wetland retention areas, parks and other nature-based solutions designed to absorb, slow and temporarily store water rather than immediately channel it away.
In Bangkok, she highlighted Benjakitti Park as an example of an urban intervention that seeks to recreate some of the functions of wetlands.
The shift is important because resilience is not simply about building higher barriers or larger drains. It is also about giving water more space within the city. That can mean restoring or protecting wetlands, creating floodable parks, reconnecting canals with public space, and using green areas as part of the water-management network.
Yet Pottinger-Glass stressed that nature-based solutions are not a substitute for basic urban infrastructure.
In many secondary cities across the region, gaps remain in drainage, sanitation and flood-management systems.
“I don’t think you can do nature-based solutions instead of this,” she said. “Nature-based solutions are more a way to increase resilience, to add multifunctionality, livability, where you already have that key infrastructure in place.”
The future model is therefore likely to be hybrid: conventional engineering reinforced by natural systems.
Climate adaptation must also be equitable
A second challenge is ensuring that resilience benefits the whole city rather than only its wealthiest districts. Pottinger-Glass warned that climate adaptation projects can sometimes contribute to displacement when new parks, waterfront improvements or flood-protection infrastructure increase property values.
“A lot of the adaptation work is being done in a manner which benefits wealthier areas, wealthier communities,” she said, noting that lower-income and vulnerable communities can be pushed out as redevelopment takes place.
That creates a tension at the heart of climate-resilient urban planning. A city may become physically better protected against flooding while becoming less socially inclusive.
Pottinger-Glass argued that urban adaptation therefore needs to be planned alongside issues such as affordable housing and displacement.
If new green infrastructure raises the value of surrounding neighbourhoods, she said, cities should ensure that existing communities can remain and benefit from the improvements rather than being priced out.
Bangkok’s canals could become an asset again
Bangkok’s historic canal network offers one example of how the relationship between water and the city could be reimagined. Pottinger-Glass noted that older images of Bangkok show a city where canals were central to everyday life and mobility.
Rather than viewing them solely as drainage infrastructure, she sees scope to reactivate canals as part of the city’s broader public-space and mobility system.
“If we can clean them up, think more about mobility,” she said, pointing to opportunities to combine water management with walkability and public space.
She also highlighted Bangkok’s growing network of pocket parks, arguing that their impact could become more significant if they are planned as a connected system rather than isolated green spaces.
“One small individual green space maybe can’t do much,” she said. “But if we have hundreds across the city… I think that can do a lot for both resilience and livability.”
A regional challenge, not just a city problem
The watershed approach also has implications beyond individual cities. Water systems often cross administrative and national boundaries, while climate risks such as flooding and sea-level rise are shared across much of Southeast Asia.
Pottinger-Glass said the region therefore needs greater exchange of experience and solutions.
“So much of this region faces shared challenges, transboundary challenges when we’re talking about climate, water,” she said. “We need to be learning more from each other.”
Her broader message is that Southeast Asia does not necessarily lack ideas. Many workable interventions already exist.
The challenge is scaling them, connecting them across cities and embedding them into mainstream urban planning.
For Bangkok and other climate-exposed cities across the region, that will require moving away from the assumption that water can always be controlled through engineering alone.
Instead, the city itself may need to become more amphibious: combining drains, pumps and flood defences with wetlands, canals, parks and other spaces designed to accommodate water.
The core principle is simple but potentially transformative. Cities will need to stop planning against water and start planning with it.