Author(s): Seren Nishijima; Makoto Nakatsugawa; Tomohiro Sandou

Linked Author(s): Seren Nishijima, Makoto Nakatsugawa

Keywords: Multipurpose dam; Emergency spillway gate operation; Snowy region; D4PDF; Combination of heavy rain with snowmelt

Abstract: This study evaluated the flood control functions of multi-purpose dams in snow-covered areas, considering the increased flooding risks associated with climate change. The target area of the study was Hoheikyo Dam in Hokkaido, located in northern Japan. In recent years in Japan, there has been an increase in the number of cases in which dams are operated at emergency spillway gate operation due to torrential summer rains. In snow-covered areas such as Hokkaido, heavy rainfall during the snowmelt period makes emergency spillway gate operation around multi-purpose dams difficult due to the high water levels. This study estimated the frequency of emergency spillway gate operation due to severe flooding based on climate change ensemble data for the whole year, including heavy rain in summers and snowmelt combined with heavy rainfall. The results indicated that the frequency of emergency spillway gate operation due to extreme flooding will increase in the future, especially during winter and at times of snowmelt. The results obtained in this study will be useful for planning flood control measures adaptable to climate change, such as pre-flood dam release, dam regeneration, and construction of new dams.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221260

Year: 2022