Examining the Impact of Built Environment on Flood Losses in Seoul, Korea

Abstract

Floods have been the costliest and most disruptive among all natural hazards worldwide. In particular, urban flooding continues to be a concern for both developed and developing countries. Increasing physical risk associated with environmental changes combined with rapid land use change and development make many urban areas more vulnerable to floods. Floods are not solely based on hydro-meteorological conditions, but result from human activities as well such as unplanned land use or haphazard development.

While there is a growing body of research focused on understanding the role of human systems on flood impacts in the United States, little empirical research has been conducted outside of the country although many other nations experiencing urban flooding. In particular, many countries in South and East Asia have undergone rapid urbanization concurrent with industrialization and population growth, resulting in worsening flood problems over time.

To address this knowledge gap, this study statistically examines the factors contributing to flood loss in Seoul, Korea, with particular focus on the built environment. Panel regression models are analyzed using actual flood loss data in Seoul from 2003 to 2012. The dependent variable is observed property loss from floods recorded each year across 25 districts and the built environment is measured by land use category and the existence of Central Business Districts (CBD). The control variables are analyzed along four dimensions: biophysical, socioeconomic, flood mitigation, and organizational capacity factors. Results indicate that urban built-up land with higher impervious surfaces and agricultural land causes more flood damage than other land use analyzed in the study. However, CBD with high development density decreases flood loss. These results indicate the importance of resilient land use planning in urban area. Also, hourly maximum precipitation increases flood loss while total precipitation is not statistically significant. This result indicates that rainfall intensity is more influential than the quantity of precipitation, providing an important indication to local governments that they should focus on improving the capacity of drainage infrastructure within urban cores. Overall, this study provides insights to planners and decision makers on how they can effectively reduce flood risk and associated adverse impacts.