An amendment to Japan’s Flood Control Act took effect on July 1, 2005, after a series of heavy rain disasters in 2004. It obliged the mayors of municipalities with areas expected to flood to inform residents, with flood hazard maps, about how flood warnings are passed on and where to evacuate.
The Ministry of Land, Infrastructure, Transport and Tourism expected the number of municipalities required to make such maps to roughly double, to about 1,800. On March 31, 2005, 375 municipalities had them.