The fact that Bangkok is struggling with the worst flooding in at least half a century should be a major wake up call for Vietnamese authorities.
Ho Chi Minh City is almost in the same position as the Thai capital.
Just like Bangkok, the southern metro is located downstream of a big river, the Saigon River, with many areas lower than the sea level. In fact, both cities often suffer floods caused by heavy rains, high tides and flooding in the rivers' upstream areas.
However, HCMC is at lower risk of facing such heavy floods as compared to the current one in Bangkok, considering that its location doesn't block the local rivers from flowing into the East Sea. Moreover, the Saigon River in spate has a flow rate of 2,800 cubic meters per second, which is much smaller than the latest flooding inundating Bangkok with some 4,000 cubic meters per second. This is not to mention the fact that upstream Saigon River, floods are controlled by hydropower reservoirs.
Still, despite its disadvantages, Bangkok has better control over floods. Over the past ten years it has basically tackled floods with a network of bag dykes and pumping water out. This time it could not avoid severe flooding because overflow from upstream areas were larger than estimated, combined with high tides.
HCMC, on the other hand, sees streets in suburban districts like Thu Duc and Binh Chanh submerged during high tides. Last weekend, water levels in the Saigon River had already reached 1.57 meters in District 2, setting up a new record, as compared to the historic peak of 1.56 meters in 2009 and 2010.
That is to say HCMC authorities need to closely observe and analyze in detail Thailand's situation and response so they can prepare the city for the worst scenario.
One of the main lessons from Bangkok is that local authorities pay too much attention to dyke and pumping systems, while ignoring, to a large extent, other solutions like building areas to contain and transfer floods. Streets and urban areas block floods from flowing into the sea. Worse still, forests in upstream areas have been badly depleted and reservoirs aren't operated properly. These two factors played a role in Bangkok's flooding.
This means that to tackle floods effectively, HCMC, which is in almost the same position as Bangkok, needs a package of measures, ranging from urban zoning to building places to contain floods, distributing pumps, especially in areas where irrigation systems aren't enough to curb flooding when it rains during high tide.
Drainage systems and forecasting abilities also need to be upgraded so they can operate more effectively.
It's time the city's authorities rolled up their sleeves to do something about floods in HCMC, properly and effectively, instead of discussing measures for years, complaining about lack of technology and budgetary constraints.
Otherwise, HCMC will face the same situation as Bangkok.
By To Van Truong
To Van Truong is the former chief of the Southern Institute for Water Resources Planning