Hanoi (VNA) - Experts have called for a comprehensive approach, grounded in science and technology and involving intersectoral, intergovernmental, and interregional collaboration, to tackle urban flooding, a growing concern in major Vietnamese cities.
Urban flooding not only causes economic losses and disrupts residents' lives but also exposes gaps in urban planning, infrastructure, and governance capacity, experts said.
In Ho Chi Minh City, flooding occurs not only during the rainy season but also due to high tides. Areas such as Binh Thanh and Thu Duc frequently experience floods of 20-50 cm, severely affecting traffic and daily life. Anti-flood projects, including underground drainage systems and retention ponds, have so far fallen short of expectations.
Architect Ngo Viet Nam Son noted that HCM City has overly focused on developing the central area with high concrete density, lacking green spaces and water surfaces, severely limiting water infiltration and drainage. Similar issues occur in urban areas in the central region such as Da Nang, Hue, and Quy Nhon, which face the combined effects of heavy rainfall and upstream floods.
Climate change has further intensified extreme rainfall, with frequency and volume far exceeding the design capacity of drainage systems, experts said, attributing these to inconsistent urban planning and inefficient operation.
Assoc. Prof. Dr. Vu Hoai Duc from Vietnam National University, Hanoi, attributed urban flooding to poor integration of ground elevation, drainage networks, and water storage, with newly developed higher-elevation areas causing water to accumulate in lower zones.
Sharing this view, architect Tran Tuan Anh added that if land elevation planning is not connected to the urban drainage network, flooding will persist regardless of the number of pumping stations or retention ponds invested in.
Statistics show that in Hanoi, many natural retention lakes have been filled in for construction, reducing natural water surfaces by over 15% in the past decade and diminishing their crucial regulation capacity. Aging and overloaded infrastructure, much of it from the French colonial era, was designed to handle only 100 mm of rain in two hours, while current storms often deliver 200-300 mm in just a few hours. Meanwhile, small and deteriorated drains clogged with debris further slow water flow, sometimes causing backflows.
Another factor identified by experts is climate change, which increases flooding risks. Experts from the Japan International Cooperation Agency (JICA) have warned that Vietnam is highly vulnerable to climate change, and they underscored the need for the country to have long-term drainage strategies and flood management plans rather than short-term reactive measures.
Flood control requires a multi-layered network
Dao Ngoc Nghiem, former Director of Hanoi's Department of Planning and Architecture, emphasised that effective flood control requires restoring lakes, ponds, and wetlands that have been filled in. Water surfaces must be considered an essential component of modern urban planning.
According to the expert, many countries have adopted the "sponge city" model, which retains water on-site through permeable surfaces, ecological lakes, and green roofs. Nghiem suggested that new urban areas in Vietnam should apply this model from the outset, rather than trying to manage drainage after construction.
In addition, combining hard and soft infrastructure should be considered, as relying solely on pumping stations and underground reservoirs without channels, retention areas, and natural solutions is insufficient.
Assoc. Prof. Dr. Ho Long Phi, former Director of the Water and Climate Change Institute of Vietnam National University, Ho Chi Minh City, stated that flood-control infrastructure must be a multi-layered network, from sloped roads to underground drains, and retention ponds - with all components working together like a cohesive ecosystem.
Flood management remains highly challenging, as new urban areas have implemented only small and fragmented measures, while comprehensive solutions require both significant time and investments of billions of USD, compounded by the impacts of rapid urbanization on the construction of flood-control infrastructure facilities.
Long emphasised the importance of engaging the private sector, which offers strong financial resources and a flexible approach, to share responsibility with the government and jointly develop optimal solutions for flooding.
He recommended using highly permeable materials and porous asphalt in sidewalks and parking lots to improve drainage, alongside collecting rainwater in underground tanks, as successfully done in Thu Duc area./.
VNA