THE DISTRIBUTION AND CHARACTERISTIC ON FREQUENT FLOODED AREA OF INLAND INUNDATION IN NAGOYA CITY

Abstract

 In this study, using the past 25 years of inundation records, we identified frequent inland water inundation areas in Nagoya City where inland water inundations have occurred more than five times in the past.

 As a result of the time-series analysis of frequent inland water inundation areas, it showed that the frequent inland water inundation areas formed between 1993 and 2005 were caused by the land-use change from rice paddies to residential areas in or around frequent inland water inundation areas. This land-use change was affected as the topographical factors of inland water inundation.

 On the other hand, the influence of land-use change was small in the frequent inland water inundation areas formed between 2006 and 2017. This suggests that the increase in probable precipitation caused the drainage channels to become insufficient in their discharge capacity designed in the 1950s, resulting in frequent inland water inundation in areas where inundation had not previously occurred.

 In addition, the frequent inland water inundation areas in Nagoya City were formed in areas with almost no slope and regardless of the direction of overflow, the mere presence of structures in the vicinity was related to the formation of frequent inland water inundation areas.