講演情報
[PS-02-34]Impact of soil moisture initial conditions on flood risk in Hokkaido, Japan
*Julie ANDRE1, Tomohito Yamada1 (1. Graduate School of Engineering, Hokkaido University)
キーワード：
flood、soil moisture、antecedent conditions、climate change
Japan is likely to see more frequent, intense heavy precipitation with warming, raising flood risk. Flood severity depends not only on rainfall intensity but on rainfall timing/space and antecedent soil moisture: saturated catchments convert more rain to runoff, amplifying peaks. The paper quantifies how initial soil moisture affects flood intensity in 18 natural Hokkaido riversheds using hourly 2002–2025 discharge data, interpolated rainfall, and ERA5 soil moisture. Peakflow events were extracted by separating baseflow from stormflow, defining rain-event start by backward accumulation, recording antecedent soil moisture, and focusing on June–October to avoid snow effects. The study statistically examines the relationship between antecedent soil moisture and the runoff coefficient.