Storm Surge Disaster by Typhoon No. 9918—Performance Design of Coastal Defense

The huge storm surge and waves of Typhoon No. 9918 attacked the southern part of Japan in 1999, killing 12 people and inflicting severe coastal damage. Not since the typhoon of 1959, which killed more than 5,000 people, had such a major disaster occurred in Japan. This is a result of subsequent construction of intensive coastal facilities against storm surges along very long coasts and especially in large bays. Here, we review the historical development and characteristics of Japanese coastal defense facilities, while also describing the recent typhoon damage and discussing problems related to current numerical tools for storm surge prediction in Japan. Finally presented is our version for future coastal design methodology, which is based on the performance design.