Crowd-Mapping Jakarta’s Flood Problem Via Twitter (Because Jakartans Love To Tweet)

With a tool tied to people’s tweets about weather conditions, citizens are helping the city build resilience.

Jakarta sees a lot of flooding. Every monsoon season, in January and February, nearby rivers rise and low-lying areas of Indonesia’s capital become inundated with water. Forty percent of the city sits below sea level.


As emergency services try to cope, they need real-time information about which areas are becoming affected. And, in the past year, they’ve had a new–and some might say, better–source for that: Twitter.

As well as being one of the most flood-threatened cities on earth, Jakarta is also one of the most Twitter-happy. Its 28 million resident make up one of the largest Twitter communities anywhere. And, now citizens are beginning to play their part in reporting and sensitizing the city to flooding risk, using a crowdsourced system called PetaJakarta.

PetaJakarta “listens in” to Tweets from Jakarta residents. When it hears words like flood (or banjir in Indonesia), it automatically sends back a Tweet inviting users to participate in mapping flooding. It asks if people are experiencing flooding, and if so, can they send back a photo, some information, and turn on their GPS?

“What’s novel is we’re going from social media to a process of crowdsourcing–collecting confirmed reports from the ground in real-time,” says Tomas Holderness, of the University of Wollongong in Australia, one of the leaders of the project. “We don’t need [a new] ‘Twitter for emergencies’, or new apps to collect situational information from citizens. Megacities in South East Asia have these communications networks during disaster situations. All we need is software that repurposes the network to be a real-time crowdsourcing data platform.”

Holderness collaborated on PetaJakarta with his colleague Etienne Turpin, Twitter in San Francisco, and the Jakarta Emergency Management Agency, which uses it day-to-day. Holderness describes it as a parallel system to the city’s formal disaster mapping. For now, it’s a reference tool–giving compare-and-contrast capability–but one it could prove itself quicker and more accurate. Future versions will show pictures and video live on the map itself.

Whether it’s Twitter or another resource, Jakarta is going to need all the flood intelligence and resilience it can get. The city is sinking rapidly because of subsidence, while, at the same time, sea levels are rising, storms are intensifying, and more and more people are moving to the metro area.


“Jakarta is threatened by 21st-century change, both climate change and urban intensification,” Holderness says. “It’s quite phenomenal that Jakarta is experiencing an increasing intensity of rainfall during the monsoon, and the city is already below sea-level in many places. All the water that moves through from the mountains has to be pumped over a six-foot high sea-wall. It only takes one of those pumps to fail, or the electricity to be turned off in the wrong place, for quite some catastrophe to unfold.”

About the author

Ben Schiller is a New York staff writer for Fast Company. Previously, he edited a European management magazine and was a reporter in San Francisco, Prague, and Brussels.