Debris disasters caused by Typhoon MALOU (T1613) in Kakidairasawa on Sept. 7, 2016

Yoshiharu ISHIKAWA, Yasuhiro SYUIN, Yoshiaki KASHIWABARA, Naoki MIYATA, Ryoichi OHNO, Satoshi TOBIOKA, Makoto KAJIHARA, Makoto NUMAKUNAI

Abstract
Debris runoff occurred due to heavy rainfall of Typhoon MALOU in Kakidairasawa, Numata City, Gunma Prefecture on Sept. 7, 2016 and caused damage on 4houses. After the disaster, research team was immediately organized by the Kanto Branch, Japan Society of Erosion Control Engineering with the aim of investigating the processes of generation, flow and deposition of debris movement and clarifying the actual conditions of debris disaster. Following features are observed:1) the debris runoff was caused by the short period torrential rainfall, 2) the debris runoff was affected by large amount of surface runoff, 3) pumice layers were exposed by the erosion of stream bed, 4) a woody debris dam was formed by deposit of logs and sediment in the stream.

Key wordsFdebris runoff, debris disaster, surface runoff, woody debris, pumice