Kumamoto Kuma River Flooding within about 60 km The area that continued to flood for nearly half a day was 4:36 on July 23.
Experts have found that the Kuma River in Kumamoto Prefecture has been flooded continuously for about 60 kilometers, which is half the length of the river, and continued to flood for nearly half a day at some locations.
Professor Yasuo Nihei of Tokyo University of Science, who is familiar with the mechanism of river inundation, analyzed changes in water level using data from 18 water gauges installed along the Kuma River.
As a result, the water level rose sharply from the dawn of the 4th of this month when the upstream and middle streams of the Kuma River had intensified, and before 4:00 am, the "middle stream" crossed the embankment at about 6 hours, two hours later. In the "upstream" area, a flood occurred across the embankment.
The water level continued to rise after that, and after 7am, 14 out of the 18 sites analyzed, or about 60 km in distance, seemed to be inundated one after another.
This is half the length of the Kuma River, which has a total length of more than 110 km, and the highest water level in the analysis was 5 meters above the embankment, and the longest flooding time was half a day. I've been there for the last 11 and a half hours.
Professor Nihei points out that "the water overflowing over the embankment was extensive and lasted for a long period of time, which may have caused serious damage to the riverside area."