Ho Chi Minh City, Vietnam's largest urban center, is grappling with a complex flooding crisis exacerbated by heavy rainfall, high tides, land subsidence, and rapid urbanization. Experts warn that merely expanding drainage systems or raising ground levels in specific areas could lead to flooding in surrounding regions, emphasizing the need for comprehensive management of water flow and surface changes across the city.
On September 29, the University of Natural Resources and Environment (HCMUNRE) in Ho Chi Minh City hosted a conference titled 'Land Subsidence and Flooding in Ho Chi Minh City: Adaptation Solutions,' attended by domestic and international experts.
Experts identified land subsidence, high tides, and uncoordinated urban development as key factors contributing to flooding. They stressed the importance of transitioning from reactive measures to a data-driven risk management system that combines continuous monitoring and early prediction.
Recently, the city's drainage systems have struggled to cope with rainfall. Since mid-September, some areas have experienced over 100mm to 150mm of rain in just 2-3 hours. The Saigon River and Nha Be Canal monitoring stations recorded water levels rising to between 1.62m and 1.67m, leading to backflow through sewage systems.
The extent of flooding is significant. According to the city's construction department, 159 locations are submerged during heavy rains or high tides. Authorities have identified 31 of these areas as priority response zones, where intense rainfall and elevated river levels coincide.
Another factor increasing flooding risk is ongoing land subsidence. A research team led by Associate Professor Le Trung Tran at HCMUNRE analyzed surface changes in Ho Chi Minh City from 2015 to 2025, revealing that areas previously unaffected by subsidence have sunk by an average of 2-5cm annually, with some locations experiencing declines of 7-8cm per year.
Flooding patterns vary even within low-lying areas, with the Phu My Hung district experiencing relatively less damage. Associate Professor Tran noted that the district was designed with consideration for its low-lying terrain and water flow from the outset. The presence of fewer high-rise buildings, along with preserved natural waterways, has allowed for adequate water storage and drainage.
Dr. Tiem Quoc Tuan, head of the Department of Geology and Mineral Resources at HCMUNRE, highlighted that Phu My Hung was once a wetland capable of storing water. While the average tidal level was set at 1.35m, the construction standard for the area is 2m. Currently, tidal levels have risen to around 1.7m, with a record high of 1.8m.
However, measures to protect one area may inadvertently increase flooding risks in others. Dr. Tuan warned that raising ground levels in one location could redirect water flow, causing localized flooding elsewhere. He cautioned that continued land subsidence and rising tidal levels could eventually put even relatively safe areas like Phu My Hung at risk of flooding.
The city's construction department has acknowledged the limitations of its current response strategies. Historically, efforts have focused on addressing individual 'flood points,' while integrated risk management and investment in key infrastructure and drainage systems have been insufficient. Rapid concrete development and the filling of ponds and lakes have further diminished the city's natural capacity to absorb rainwater.
Flooding issues are not confined to Ho Chi Minh City; they are spreading to other regions, including Hanoi, Da Lat, Phu Quoc, and the Mekong Delta. In Da Lat, urban roads have been submerged, and cracks up to 50 meters long have appeared on the Mimosa Pass. In Lam Dong Province, over 7,200 hectares of farmland have been flooded.
Additionally, Phu Quoc has seen over 120mm of rain, leading to flooding on major roads, with water levels rising between 0.5m and over 1m. Local authorities attribute these issues to rapid infrastructure and tourism development, which have altered natural landscapes, while drainage systems remain inadequate. Major rivers and canals leading to the sea have been filled in or obstructed by construction and debris, further hindering drainage.
Ultimately, the flooding crisis in Ho Chi Minh City cannot be resolved by simply draining one area or raising ground levels. With extreme rainfall, high tides, land subsidence, and a reduction in natural retention spaces all contributing to the problem, the key challenge remains transitioning from reactive measures to a comprehensive risk management system that anticipates water flow and surface changes across the entire city.
* This article has been translated by AI.
Copyright ⓒ Aju Press All rights reserved.