Keywords:September 2015 Kanto and Tohoku heavy rain, Kinu-river floods
Our research team conducted an investigation on the Kinu-river flood events occurred on September 10th, 2015, and we have uploaded our reports relatively early stage on the internet (the first report was open public at 9pm on September 14). The media rushed to the scene after a long time in the metropolitan area, so that it seems that there was sufficient amount of information delivered to the public. However, the information that is really needed were often missing, and there were misunderstandings or a hoax that caused confusion. What to be done by the experts are: to capture the events from the eyes of a professional and to provide information such as the media would be overlooked and/or to sort the information closer to the truth. This time, we had special attention, i.e., while investigating the scene if needed, we collected and analyzed real-time data which exist fairly accessible today and interpreted them in objective manner, and all of them were performed as quickly and accurately as possible. Based on that, after the first report on September 14th night, we went to the secondary survey on 15th, and updated the second report on 19th morning, and went for the third survey on the same day. In these works, our team force was extremely important, and I want to thank again to the students and the staffs that have been involved. On the other hand, it was found that as well as our team, there was a number of research groups doing similar. Among them, a group led by Associate Prof. Shirakawa in the University of Tsukuba conducted a month-long afflicted survey, and Associate Prof. Sayama in Kyoto University estimated the maximum inundation depth by using the latest GPS technology. While these individual activities were indeed remarkable, there was a limit to those activities, and some of overlaps and lacks were inevitable as a whole. Therefore, it is very important to provide a forum for information exchange and traffic control by the leadership of academic societies such as one done in this time by the joint investigation group by Japan Society of Civil Engineers and Geotechnical Engineering Society.