Analyzing green space as a flooding mitigation – storm Chaba case in South Korea

Abstract

A tropical storm Chaba hit the southeastern part of South Korea in 2016. Ulsan, the 8th largest city in terms of the number of population, was especially damaged with heavy flooding, and the calculated damage was approximately $500 million. By using Normalized Differences in Vegetation Index (NDVI), four districts and 46 sub-districts in Ulsan city, South Korea. Analysis results indicate that having a higher proportion of green space inside a city could have a reduction effect on flooding risks. 1 km2 of increase in green space could reduce financial insurance payment of flooding by $44,099. In addition, an increase in non- green space also could have raised insurance payment by $691,094. The result confirms that green space inside floodplain is more effective than its existence outside floodplain. The difference is about 21 times ($44,099 vs. $953,755). Green space can mitigate flooding impact to a certain degree and it could be used to determine how natural disaster policy in municipal level should be organized. In addition, it can also provide a foundation for claiming insurance payments to those facilities without careful considerations on environmental planning.