The impact of anthropogenic changes on socioeconomically marginalized population in urban areas: A case study of flood risk in Seoul, South Korea

Climate change, one of the most remarked anthropogenic changes, has increased the intensity and frequency of heavy rainfall events. Heavy rainfall events pose challenges especially in urban areas, which have a higher rate of impervious surface, compared to non-urban areas. Seoul, the capital city of South Korea is not an exception for the cities that contend with flooding. During summer, the meteorological condition forming over the Korean peninsula brings rainfall constituting approximately 35-55% of the country’s annual precipitation. Seoul has undergone rapid development and urbanization, which also are the examples of anthropogenic changes, for the last five decades; the city’s current population is about 4.7 times larger than that of the early 1960s. This fast population increase created a distinctive housing type known as semi-basement housing, symbolizing socioeconomic marginalization. Despite ongoing efforts by the Seoul Metropolitan Government to mitigate flood risk citywide, most of the households living in the semi-basement housing, particularly in low-lying areas, remain highly susceptible to flooding whenever heavy rainfall events occur. This study focuses on Gwanak-gu, one of Seoul’s 25 districts and the district with the highest concentration of semi-basement housing. The study examines how anthropogenic changes in both physical (i.e., climate change) and social (i.e., urban development and urbanization) environment exacerbate the already marginalized people’s vulnerability floods. The results show that the same amount of heavy rainfall (e.g., 100mm per hour) pouring in the district significantly heightens the level of exposure for the semi-basement housing than the exposure level of housing that is not semi-basement. This implies that the climate change and urban development and urbanization (i.e., anthropogenic changes) make the vulnerable people even more vulnerable, even as the measures aim to alleviate overall flood risk across the city have been implemented. In other words, anthropogenic changes, even though the government’s risk mitigation efforts exist, tend to polarize the vulnerability and exposure to floods. Drawing from the results, the study emphasizes the need for more considerate measures to truly reduce the flood risk of the city. It concludes by suggesting potential strategies that could contribute to reducing flood vulnerability of the marginalized populations and lowering overall flood risk in the city.