Abstract: This paper presents a novel method for urban flooding risk assessment, incorporating social information that was not yet or less considered in previous studies. We have obtained flooding data from an urban storm water model and collected social information from webpages using the web crawler technology. Then, using these two types of information, we build an assessment index system of urban flooding and an exponential model, so as to achieve a comprehensive evaluation of urban flooding risk for the study area. Application to a study site, the Qingnishier region in Dalian, shows that for the 50- and 100-year return periods, the calculated areas of high-risk zones are 0.53 km2 and 1.24 km2, respectively, if only the flooding information is taken into account, while they become 1.12 km2 and 1.50 km2, respectively, if the social information is also included, revealing considerable increases in the latter case. Incorporating social information in the model will significantly raise the flooding risk level in strategic locations such as densely populated urban areas, traffic arteries, but it will lower the risk level in those unimportant areas, which indicates an improvement of the modeling.

Key words: urban flooding, urban storm water model, social information, storm rainfall and flooding, risk assessment