Heavy rains caused by storm No. 10 left large parts of Hanoi submerged. More than just an alarming reality, the situation is a stark warning about the capital city’s weaknesses in urban management.

Urban expansion outpaces outdated infrastructure

Speaking to VietNamNet, architect Pham Thanh Tung, an independent urban planning expert, remarked that the prolonged rainfall from September 29–30 rendered Hanoi nearly paralyzed, with no effective emergency response.

Daily life was severely disrupted. Residents struggled as traffic ground to a halt under floodwaters that engulfed numerous streets, wards, and neighborhoods - from central districts to major roadways like Thang Long Boulevard, Belt Road 2, and Belt Road 3.

Just a month earlier, at the end of August, heavy rains from storm No. 5 had already submerged many Hanoi streets.

Recalling the 2008 flood, Mr. Tung noted that today’s flooding occurred under entirely different urban conditions, further exposing Hanoi’s vulnerabilities.

“In 2008, the urbanized area across four inner districts spanned about 250 square kilometers. Today, it’s over 900 square kilometers - nearly four times larger,” he explained.

“Agricultural land, lakes, ponds, and wetlands that once absorbed rainwater have been paved over with concrete, severely reducing natural drainage capacity.”

Tung noted that Hanoi has focused heavily on expanding urban space - building high-rises and major roads - while failing to invest in a comprehensive drainage system.

“We’ve prioritized a polished, glamorous urban image, but investment in core infrastructure such as drainage, water retention, and pumping stations has been insufficient,” he emphasized. “The city’s water drainage system is extremely underdeveloped, a flaw rooted in poor overall planning.”

Currently, Hanoi is still largely dependent on the underground drainage system built by the French over a century ago, when the city had a population of just 250,000. Today, the urban population numbers in the millions, and wastewater and stormwater volumes have far exceeded the system’s design limits - especially as climate change makes weather patterns more extreme.

“Because upgrades and renovations haven’t kept up with urbanization, just one major downpour is enough to leave the entire city flooded,” he said.

Another crucial element of stormwater management - natural lakes - has also diminished significantly, with many retention lakes filled in or encroached upon. The loss of these “lungs” of the city has further compromised drainage.

In addition to infrastructure issues, Mr. Tung said Hanoi also lacks emergency response strategies and climate resilience planning. As a result, authorities were unprepared and slow to act.

Residents received no timely warnings and were caught off guard by the rapidly rising floodwaters. In many areas, floodwaters remained for dozens of hours after the rains stopped.

“Despite living in a digital age, Hanoi’s crisis management and leadership response were inadequate. While leaders in other provinces visited flood zones to provide guidance and assistance, no Hanoi city officials were seen on-site on September 30,” he criticized. “That’s something that must be seriously considered.”

Uneven ground levels and fragmented development

Mr. Tung also highlighted uncoordinated development along newly built roads. These urban zones sprang up rapidly but often lack integration with the city’s overall drainage system.

Additionally, Hanoi still lacks a comprehensive elevation map. Many streets use sidewalks as reference levels, creating inconsistent ground elevations and chaotic urban planning.

Flooding in Hanoi is no longer just a matter of unavoidable natural disasters - it reflects deep gaps in planning and governance. While solutions won’t come overnight, Mr. Tung believes the city must urgently review all data and planning assumptions.

“This flood is not the last,” he warned. “There will be more storms and depressions from now until the end of the year and in the years to come. Without long-term solutions, Hanoi will remain in disarray whenever heavy rains hit.”

He concluded, “We must invest seriously in completing the drainage infrastructure. We can’t keep talking while doing nothing. Underground water retention tanks - common in many countries - are essential for both water security and flood prevention.”

Hong Khanh