Bangkok’s flood walls are 2.5 meters high. In Oct 2010, the terrible flood that ravaged much of the Northeast and Central regions came dangerously close to that limit, reaching roughly 2 meters, despite Governor Sukhumband’s fears that it would reach 2.3 meters.

The Odds

Pornthep Techapaiboon, Deputy Governor of Bangkok, told BK: “Bangkok is at risk from floods from three sources: localized rain, floods from the North and rising sea levels. We have levees on the Chao Phraya River that can withstand up to 2.5 meters of water above sea level—that’s for floods coming in from the North. We’ve also completed seven giant new drainage systems, which can drain 155.5-cubic meter/sec—that’s almost four standard swimming pools emptied in one second, stretching around town from Phaya Thai to Ladprao. These drainage pipes are 20-30 meters below ground level and can drain off water from flooded areas in eastern Bangkok directly to the Gulf of Thailand. Based on past data and our budget, this is the most we can do. But irregular things can happen—and tend to happen more and more these days—so we don’t really know what we are facing in the future.”

The Plan

Again, Deputy Governor Pornthep: “There are three more giant drainage pipes to be built with the total project scheduled to be completed in 2016. Normally the amount of rainfall in Bangkok is at around 1,900mm per year while the system is designed for an amount of 2,500mm per year or 60mm per hour.”
Ironically, New Orleans’ levees were scheduled for completion by 2015. And there is also the question of rising sea levels. Pornthep says, ““In the last 10 years, around 5,000-rai of space have been eroded by higher sea levels and waves. For now, we’re working on the bamboo project. Sticks of bamboo are lined along our coast so when waves come in these sticks will retain soil, sand and mud before the water goes back to the sea. These muddy spaces will later turn into mangrove forests. Bamboo sticks can stay for around five years so for the long-term, we need to cast t-shaped concrete barriers to be dropped along the coast. The budget for this is now being finalized.”

The Case Study

In the August 2005 Hurricane Katrina, the levees protecting New Orleans broke, flooding the city with as much as 4.5 meters of water in some parts. 1,464 people died and one study estimated the total economic damage at over US$150 billion. Although caused by a hurricane, it does give some notion of what damage a massive flood in a densely urbanized area can wreak.

If your home is sinking, do this:

• Shut off the electricity at the main circuit breaker.
• Collect a survival kit (see box).
• Don’t drive, don’t try to escape. Just move to the top of your building.
• Avoid water. Swimming in flooded water puts you at risk of electrocution caused by damaged electric wires.
• Beware of animals like snakes or scorpions which will also try to move to dry areas.