The Experience with the Urban-Type Flood Disaster on Two Occasions and Subsequent Countermeasures in Nagoya

In September 2000, Nagoya was hit by the Tokai Heavy Rain, the city's highest-ever recorded rainfall, which caused extensive damage such as dike breaks and inundated 40% of the city's area. Since then, countermeasures for improving rivers, sewerage systems, and pumping stations have been implemented. Moreover, “Stormwater Information” showing the real-time statuses of pumps has become available on the internet. While these projects were underway, another torrential stormwater occurred at the end of August 2008. Although this heavy rain caused extensive damage again, the damage from inundation was considerably less in areas where countermeasures implemented after the Tokai Heavy Rain had been completed. Based on its experiences with these urban-type flood disasters, City of Nagoya decided to direct the increased drainage into rivers, install stormwater reservoir pipe along routes for future flow pipes, conduct public relations on setting rainwater inlets at individual homes, and release hazard maps for all residents.