Experts are urging Hanoi to move from the mindset of “fighting water” to “living with water” by transforming existing urban spaces such as parks, plazas, and parking lots into temporary rainwater reservoirs during heavy storms or tidal surges.
Empty promises and overflowing streets
On the morning of October 7, heavy rain submerged many streets across Hanoi, turning parts of the capital into vast pools. This was just over a week after Storm Bualoi caused several districts to remain flooded for 4–5 consecutive days.
Speaking with VietNamNet about Hanoi’s flooding situation, Dr. Bui Sy Loi, former Deputy Chairman of the National Assembly’s Social Affairs Committee, said the recurring floods stem in part from relentless construction, while drainage systems have not been upgraded in parallel. Just a single storm is now enough to cause severe flooding.
“The capital’s urban planning must be revisited. If Hanoi keeps looking like a river, that’s not something we can accept,” he said.
Dr. Loi proposed that the city government should reevaluate local infrastructure, especially in high-rise residential areas and urban zones. Drainage issues must be resolved in these places first. Developers should not be allowed to finish buildings, sell them, and then leave residents to fend for themselves.
Hanoi residents are enduring days when city streets feel like rivers. Photo: Nam Khanh
Additionally, Hanoi’s planning must include enhanced drainage infrastructure that can rapidly drain excess water during flooding events.
Previously, some city departments had declared that Hanoi would be free from flooding by 2010. According to the former National Assembly member, these promises were never fulfilled.
Moreover, the city often proposes strategies and action plans but lacks the funding to implement them. As a result, many projects get stuck. This issue is not unique to Hanoi.
Dr. Vu Thi Hong Nhung of RMIT University noted that flooding is no longer just a seasonal issue but has become the “new normal” for urban areas in Vietnam.
She explained that outdated drainage systems are overwhelmed, and traditional infrastructure like dikes and tidal gates are increasingly ineffective in the face of unpredictable climate change.
Turning parks into water reservoirs?
According to Dr. Nhung, to adapt effectively, Hanoi must change its approach from resisting water to coexisting with it. This means repurposing urban areas like parks, plazas, and parking lots into temporary water storage zones during storms and high tides. This strategy is known as the “dual-function” infrastructure approach.
This is not a new idea globally. Cities such as Rotterdam (Netherlands), Copenhagen (Denmark), Singapore, Tokyo (Japan), Seoul (South Korea), and several urban centers in China have pioneered the use of sponge parks and water plazas.
These areas serve two purposes: under normal conditions, they are community spaces, but during storms, they function as temporary retention basins following the principle of “slow - hold - soak - release.”
Dr. Nhung cited Rotterdam’s Benthemplein Square, which features three basins of varying depth, serving both as sports courts and rainwater collectors for nearby residential areas.
To end post-storm flooding, Hanoi must shift from resisting water to embracing it. Photo: The Bang
In Singapore, the "Active, Beautiful, Clean Waters" program transformed the Bishan–Ang Mo Kio concrete canal into a scenic river park with floodplains that blend flood control with community space.
Copenhagen implemented an extreme rainfall management plan that turned streets and parks into a controlled surface drainage system, including underground tanks in key areas to help the city better withstand intense downpours.
Seoul restored the 5.8 km-long Cheonggyecheon Stream, replacing a highway with a riverside park that not only reduced flooding but also improved air quality and microclimates.
Even megacities are combining such strategies with large-scale underground infrastructure. Tokyo’s 6.3 km-long underground flood discharge system includes massive regulating basins capable of releasing 200 m³ per second, protecting millions from flooding.
In China, the “sponge city” model has been in place since 2014, integrating green and gray infrastructure to absorb and reuse 70–80% of urban rainwater.
These models show that flexible, multi-functional green infrastructure not only prevents flooding but also improves quality of life, boosts real estate value, and shapes sustainable urban identities, Dr. Nhung added.
Returning to Hanoi, after Storm Bualoi, the capital experienced extensive flooding and heavy economic losses. Thus, integrating water retention infrastructure into parks, lakes, and residential areas is vital.
Building on this, Dr. Phan Thanh Chung of RMIT University suggested converting part of Thong Nhat Park into a temporary reservoir with a storage capacity of 8,000–15,000 cubic meters. This could help drain floodwaters from central districts such as Hoan Kiem and Hai Ba Trung.
He also proposed restoring and expanding the Red River corridor into a flexible ecological buffer zone, capable of retaining upstream water and mitigating downstream flooding.
In suburban industrial zones like Dong Anh, Hanoi could build underground tanks to reduce pressure on existing sewers. These should be coupled with green infrastructure capable of absorbing up to 70% of rainfall, easing the burden on old drainage systems.
“Urban flooding can’t be solved by hardened dikes or tidal gates alone, especially after major storms like Bualoi. That’s why Hanoi needs to shift toward a ‘living with water’ model, turning parks, plazas, parking lots, and river corridors into water-storing infrastructure,” Dr. Chung concluded.
Vietnamnet.vn
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