1. 1) Ministry of Land, Infrastructure, Transport and Tourism Social Infrastructure Development Council : About water disaster countermeasures based on large-scale wide-area heavy rain - Urgent measures to prepare for multiple disasters-Report, https://www.mlit.go.jp/policy/shingikai/s304_daikibokouikigouu01_past.html, 2018.
2. 2) Water and Disaster Management Bureau, Ministry of Land, Infrastructure, Transport and Tourism : Current status of flood risk in Japan, River business overview 2018, pp. 1-11, 2018.
3. 3) Sewerage Department, Water and Disaster Management Bureau, Ministry of Land, Infrastructure, Transport and Tourism : Guide for promoting water-level observation in sewer pipes, etc. (draft) Material 2, pp. 139-177, https://www.mlit.go.jp/common/001193245.pdf
4. 4) Ministry of Land, Infrastructure, Transport and Tourism Chubu Regional Development Bureau, etc. : For example, Common specifications for river patrol work, https://www.cbr.mlit.go.jp/architecture/kensetsugi-jutsu/kijyun/pdf/h2204_sonohoka06.pdf
5. 5) Ministry of Land, Infrastructure, Transport and Tourism : H27 Flood Control Law Amendment, http://www.mlit.go.jp/river/suibou/suibouhou.html, 2015.