Author(s): Tsubasa Kawai; Makoto Nakatsugawa; Junya Seki

Linked Author(s): Tsubasa Kawai, Makoto Nakatsugawa

Keywords: Climate uncertainity; Erosion risk; Steep slope river; D4PDF; IRIC

Abstract: This study aims to analyze external forces and estimate high erodible sites under the current and future climate scenarios using d4PDF downscaling data (large-ensemble dataset). The Toyohira River, a tributary of the Ishikari River, is a rapidly flowing river that flows through the urban Sapporo area. Its high-speed currents lead to conditions that have traditionally made the area vulnerable to flooding, owing to which erosion is likely to occur. To estimate high erodible sites, we first calculated the outflow of 3000 and 5400 cases of d4PDF data based on current and future climate forecasts, respectively. Next, the current and future climate scenarios were classified according to the rainfall distribution using cluster analysis, and the external forces were analyzed. In addition, the high erodible sites were evaluated from the calculation of hydraulics on the Toyohira River channel using the results of outflow calculations in the current and future climate scenario as an external force. Thus, it was estimated that flooding greater than what has been previously experienced will occur owing to climate uncertainty in the present and future days. It is further estimated that some areas are highly erodible, and care should be taken when planning river management strategies.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221259

Year: 2022