Flooding in Ho Chi Minh City

SOURCE: CLIMATE-DATA.ORG

Ho Chi Minh City sometimes reminds me of New Orleans, mainly because it sits in a delta and is always flooding. New Orleans is actually below sea level, or some of it is. HCMC is at an average of 0.5-1.0m, so a little bit better, but not by much. Of course, climate change is also not helping, and the rainy season is long with high precipitation throughout.

The city has started to make some changes. The first is to do remote sensing in the short term, in order to help redirect traffic. If the water level gets above a certain level, the sensor will send out an alert to everyone on the alert, telling them to find another round. This seems like basically unhelpful in the long term (it doesn’t solve the flooding problem), but it will be nice in the short term. Also, the more sensors out there, the better the response to flooding, because the city will have data about what is flooding and where it is worst. Second, the government is implementing some infrastructure solutions that should help the problem on a key street (where the sensor is being placed), but this won’t be ready until after the 2020 rainy season!

SOURCE: WORLD BANK

Another idea is to for consumers and businesses to do more rainwater harvesting, with the idea that if every home collects a little rainwater, then millions of cubic meters of rainwater can be diverted from streets. This seems very unlikely to have much of an impact, but if enough people do it, maybe something could happen. Plus, it would be good to recycle this water. It would help offset the load on the system a bit.

In terms of real responses to flooding and climate change, this study suggests that increased elevation (build new buildings on top of sand in order to raise their elevation a bit) and dryproofing buildings can really help against future flooding.

Climate change and this flooding are quite difficult to deal with, but at the same time, other countries would love to have this amount of rain. For example, Vietnam gets 1,821 mm of rainfall a year, while Egypt gets 51! Jordan just 111. Iran 228. These are dry countries that face drought conditions on a daily basis. Vietnam, if it could just direct some of that rain away from the streets and store it for the dry season, would never be thirsty. But that’s hard to do.