Rapid Urban Flood Damages Assessment Enabled By Social Media and Online Web Applications

Nowadays, it is not extraordinary to hear the news reporting unprecedented and unexpected rainfall amount fallen some urban area causing city-wide flood damages. In Korea, the situation looks ‘New Normal’ as the former US vice-president Al Gore said. Last year, Chungju and Incheon urban floods exhibited these conditions. Unfortunately, there were no proper countermeasures to mitigate flood damages caused by more than 100-year frequency rainfall in few hours. Under this circumstance, it is expected more flood damages would follow because urban water infrastructure reworks are very slow and expensive. As we are improving the existing drainage structures in long-term scale, other measures should be introduced to reduce on-going urban flood damages. Fortunately, a hope comes from the rapid flood damages assessment using social media and online web applications. As Rosser et. al.(2017) said, smartphone uses in society are sky-rocketing, social media plays very impressive and pervasive role in urban society to share flood information both in real-time and post-flood basis. Also, online web applications such as DTM embedded topographic maps with prior scientific simulations created a new approach called ‘big data-driven rapid flood damage assessment.’ In this study, a fast urban flood damages assessment was depicted and the temporal and spatial progress of urban flood in Chungju was visualized. Also, the absence and the shortage of measured weather and stream data were overcome. Like a forensic analysis in CSI movie, it was possible to know how flooding was started and progressed as time goes with much more detailed pictures compared with the conventional post-flood analysis.