Lessons learned from the Katrina storm surge and the development of storm surge disaster prevention in Japan

Abstract

The present short communication will reflect on lessons that were learned by Japanese coastal engineers and disaster risk managers from Hurricane Katrina, together with those from major Japanese disasters that have taken place in recent times, such as the 1959 Ise Bay Typhoon and the 2011 Tohoku tsunami. Following a JSCE-led survey of Katrina’s impact, Japanese researchers integrated their findings on the characteristics of that disaster into Japanese disaster risk management philosophy, emphasising structural upgrades, hazard mapping, and evacuation planning. While this has helped risk management in the last 20 years, rising sea levels, the potential for more intense future typhoons, and weakened westerlies could have an effect and increase future storm surge heights. Currently, Japan’s two-tiered defence strategy—physical barriers designed against 100-year events and evacuation systems for 1,000-year events—guides current policy, but this may have to be reassessed to deal with the effects of future climate change. The present paper will also outline reconstruction philosophy and countermeasures employed after the 2011 Tohoku earthquake tsunami, including seawalls, elevated land, and urban retreat, which can serve as global references for disaster risk management elsewhere.