Ho Chi Minh City, the former Saigon, is located along the river Sai Gon, in the geographical transition from the low mountains of the hinterland to the water-logged Mekong Delta. Urbanisation makes Ho Chi Minh City one of the fastest growing cities in the world. The last few decades, its population has doubled every seven years. In times of climate change, the city is extremely vulnerable, due to ongoing subsidence, lack of space for water retention, and high densities of living.

From 2011 to 2015, BoschSlabbers worked on these issues, as part of the VCAPS-consortium, under supervision of the then Grontmij (nowadays Sweco). The consortium developed a strategy to better prepare this low-lying and fast-growing city for climate change’s negative effects: a strategy to make Ho Chi Minh City climate adaptive.

Flooding and heat stress

The city is negatively impacted most of all by flooding and heat stress. Parts of the city are so low-lying they are inundated every month, at each full moon. Water levels in the streets may rise to 40 centimetres. This causes much inconvenience, but does not pose specific water risks. The expectation, however, is that growing wealth will lower public acceptance in the future.

Aside from these monthly ‘floodings’, there is a more serious threat of floods in periods of extreme rainfall, when rainwater rushes from the hills in the hinterland through the city towards the ocean. These floods are less predictable and pose more risks: they emphatically threaten water security (i.e. human life).

Heat stress is everywhere in this densely populated city, where densities of more than 90 households per hectare are no exception. The city has little opportunity to get rid of its accumulated heat to its surroundings in the night. The negative effect this has on urban living conditions is intensified by high concentrations of fine particles, caused by busy urban traffic.

Without intervention, both sea level rise and changing precipitation patterns (more frequent occurrence of more extreme peak rainfall) predict an increase in flooding and a decrease in water security.

Project research showed that while the effects of sea level rise are already significant, they are surpassed by the effects of subsidence, which is a direct consequence of excessive groundwater extraction.

From design charettes to strategic approaches

In a series of ‘design charrettes’ (intensive design ateliers over several days), in which Dutch know-how was paired with local expertise, six strategic approaches were formulated, on the scale level of the city and its surroundings:

• Base the trajectory of urban development on soil and aquatic conditions.
• Develop a step-by-step approach to prevent flooding.
• Enlarge the city’s capacities of water retention and drainage.
• Prevent salination where you can and develop saline agriculture where this is not possible.
• Shift from groundwater extraction to the use of surface water.
• Enhance green and blue networks in the city and optimise natural ventilation.

Each of these approaches was then translated into concrete interventions.

Two case studies

Subsequently, these general recommendations have been developed further for two districts, to serve as model examples. It made tangible how implementation impacts future area development.

In the final phase, a vision for one of these districts (district 4) was developed to the level of concrete interventions. This enabled the team, including city professionals, to work its way through the full design process, on every scale level. The design vision on the scale of the city and its surroundings was, via the city level, made more concrete at the level of the districts (the administrative units of the city), and then translated into detailed interventions. It provided Ho Chi Minh City with a practical strategy to work towards climate adaptation.

More information, including the final report, can be found on and downloaded from the website of VCAPS.