2020年9月9日に群馬県北部で発生した局地的豪雨に伴う みなかみ町東峰区・奥田区における災害の記載

On September 9, 2020, there was localized heavy rain mainly in the northern part of Gunma Prefecture. In Minakami Town, 56 mm of rain was recorded in one hour, the largest on record for September observation. In Higashimine Ward and Okuda Ward of Minakami Town, this torrential rain caused debris flows that flowed into forests, fields, houses, roads, irrigation water, and rivers. There was also burial, and damage caused by the collapse of seawalls and shores. In Higashimine Ward and Okuda Ward, there is the Oshino irrigation water system opened by Sanada Nobutoshi in the 4th year of Kanbun era（1664）, and it has been maintained and preserved on a daily basis even today. The Oshino irrigation water system was also buried or collapsed by debris flows which led to this study. Therefore, from August 2021, we conducted a field survey along the Oshino Irrigation Line, Izumiyama, Higashimine and Okuda in the early morning of September 9, 2020. [ABSTRACT FROM AUTHOR]

2020年9月9日未明, 群馬県北部を中心とした局地的な豪雨があり, みなかみ町では9月の観測史上 最大となる1時間で56ミリの雨が記録された．みなかみ町東峰区, 奥田区ではこの猛烈な雨によって土石 流が発生して山林, 田畑, 家屋, 道路, 用水, 河川に流入し, それによる埋没や護岸や畦の崩壊の被害を 受けた．東峰区, 奥田区には寛文4（1664）年に真田信利が開いた押野用水があり, 現在まで日常的に維 持管理され保全されてきた．押野用水も土石流による埋没や崩壊の被害を受けた．本論文では, 2021年8 月から押野用水沿線, 泉山, 東峰, 奥田で行った野外調査の結果を基に, 2020年9月9日にみなかみ町東峰 区, 奥田区で発生した豪雨災害について押野用水に係って記載・報告する. [ABSTRACT FROM AUTHOR]