Da Nang (VNA) – The central city of Da Nang is exploring the “sponge city” model and other nature-based solutions to strengthen its resilience against urban flooding as climate change and rapid urbanisation place increasing pressure on existing drainage infrastructure.
Recent extreme rainfall events have exposed the limitations of traditional flood-control systems. During the historic floods in late October 2025, more than 100,000 houses were inundated, dozens of communes and wards were isolated, and economic losses exceeded 3.1 trillion VND (124 million USD).
Experts said Da Nang’s steep terrain, short river systems and extensive urban development have reduced the city’s natural flood-retention capacity. Urban expansion, land filling and transport infrastructure projects have altered natural water flows, contributing to more prolonged flooding.
According to Dr. Architect Hoang Duc Anh Vu of the Da Nang University of Architecture, Da Nang is a typical central coastal city characterised by significant elevation changes, ranging from 1,450 meters at Ba Na Mountain in the west to around 50 metres in the eastern coastal areas. This steep topography causes rainwater to flow rapidly toward low-lying coastal zones during the rainy season. Da Nang’s river systems are short and steep, discharging directly into the sea, which means that water from upstream areas quickly converges on urban districts during heavy rainfall.
In addition, tidal surges and sea-level rise have reduced the ability of rivers to drain into the sea. High construction density, limited water-retention spaces, and weak integration between green spaces, water bodies, and natural drainage corridors have further diminished the city’s resilience, making Da Nang increasingly vulnerable to heavy rainfall and high tides, he added.
Research by Dr. Le Hung and Associate Professor Dr. To Thuy Nga from the University of Science and Technology – The University of Da Nang, said that flooding patterns in Da Nang have shifted from “rapid rise–rapid recession” to “prolonged inundation,” a trend that became particularly evident during the extreme flood events of 2025. Urban expansion and transportation infrastructure development have significantly affected the city’s natural flood-drainage capacity.
Researchers have recommended that the city move from a flood-control approach to adaptive planning based on river basins, while expanding water-retention spaces and protecting natural drainage corridors. Green infrastructure measures, including rain gardens, green roofs and urban water-storage systems, have also been proposed.
Under the “sponge city” model, urban areas are designed to absorb, store, filter and reuse rainwater through integrated green and blue infrastructure. Experts believe the approach could help transform water from a source of risk into a key element of sustainable urban development and climate adaptation.
Vice Chairman of the municipal People’s Committee Le Quang Nam said the unprecedented flooding in 2025 highlighted the growing threat of extreme weather events. He affirmed that the city would incorporate scientific recommendations into urban planning, architectural management and infrastructure investment to enhance long-term resilience./.
