Gifu Gero's Inundation Damage Caused by "Water Jump" Phenomenon in Irrigation Canal or July 16 at 5:50
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In Gero City, Gifu Prefecture, where many houses were flooded by record heavy rains, the water in the irrigation canals flooded with a phenomenon called “jukisui,” in which the water drastically increased due to changes in the slope. , It was found from the video obtained by NHK and the research by experts that it seems to have contributed to the spread of damage.
In Gero City, Gifu Prefecture, record heavy rains have caused damage to more than 190 houses, etc., and in the Hagiwara Town Hane area, a large amount of rainwater flowing down the valley was spread over the area. Approximately 30 houses and other buildings were damaged due to flooding of agricultural irrigation canals.
In the video of one irrigation channel taken by the residents of the district around 5:30 am on the 8th of this month, which was acquired by NHK, the flow of water suddenly overflowed, flooding the surrounding area and flowing toward the house. The situation was photographed.
Associate professor Hiroshi Takebayashi of the Disaster Prevention Research Institute of Kyoto University, who specializes in river engineering, conducted an on-site survey and analyzed the images, and found that there was a phenomenon called "jumping" in which the flowing water rapidly increased in bulk.
In this place, the slope of the irrigation channel suddenly became gentle, and the fast water flow collided with the slowed water. It is believed that it contributed.
Associate professor Takebayashi said, "There are many irrigation canals that are at risk of jumping in farmland in the mountains with many slopes. Be aware of the places at risk and be alert when building sandbags, and when developing canals. Should consider the structure in consideration of jumping water."