Using twitter to get ground truth on floods

Interview with Floodtags founder Jurjen Wagemaker at Global Pulse: “…Twtitter has proved to be a fantastic flood monitor tool and we encourage people to share even more of their flood experiences on Twitter. Now the difficult part is, to create the right flood filters and enrichments, so that disaster managers only need to look at a fraction of the hundreds of thousands of observations coming in.

So we enrich and analyse all flood data in real-time, and present them in an understandable format through our web service. A good example is the water depth of a flood. It turns out that a large number of people both mention the flood depth as well as the location where they monitored it. Take for instance January 29th, 2014: out of the 360.000 tweets we collected on floods, 15.000 included water depth observations (see picture). Together with the Dutch water management institute Deltares (@arnejanvl) we are working to develop a sound interpretation framework for these observations to create real-time floodmaps. For reference, to make a reliable floodmap of the January 2013 flood took a total of nine days. This was thanks to the hard work of the disaster management office and the HOT team (Humanitarian OpenStreetMap Team)….
We will launch the site at the upcoming Data Innovation for Policy Makers conference in Bali. And from that date onwards you can use Floodtags to get realtime flood information in Indonesia. Just go to and sign-up. Especially when it rains it can become quite interesting: you can search for different neighbourhoods and see what people tweeted and how deep the water is. There is also a realtime tweet density map and you can request tweet statistics (e.g. figure 5, where we compare flood tweets with flood response tweets) – and we have got so much more to come. “