平成30年7月豪雨による関西における災害

抄録

From 5^th to 7^th July 2018 in various parts of western Japan, continuous heavy rain occurred due to Typhoon Prapiroon supplying warm moist air towards the baiu front, and caused numerous disasters. The Japan Meteorological Agency named it “the Heavy Rain Event of July 2018” and the damaged area extended widely from western Japan to Hokkaido. In Kansai region, serious sediment disasters occurred including human damages. Therefore, Japan Society of Erosion Control Engineering Kansai branch members conducted field surveys in Hyogo and Kyoto Prefecture. In Ayabe City, Kyoto Prefecture, slope failure occurred on a thick soil layer containing a lot of fine sediment and high water retentivity. It was presumed that the rather large scale slope failure occurred due to the great increase groundwater level resulting from 30-50 mm/hr rainfall causing just after 170 mm/3 days. In Tanigo River, Fukuchiyama City, Kyoto Prefecture, landslide dam have formed due to the slope failure from right bank side. Although the landslide dam upstream water level monitoring has been conducted, the risk of landslide dam outburst need to be considered. In Kobe City, Hyogo Prefecture, many landslides and debris flows occurred and caused flooding/deposition damage in wide area. Fortunately there were no human damages, but some of the sediment have extended to the outside of sediment disasters designated areas. Although it might be difficult to predict and realize the sediment disaster risk in residential area because torrents width become rather narrow and landform changing due to land development, we need to consider effective countermeasures.