CHANGE IN POTENTIAL FLOODING PATTERN IN THE ARAKAWA RIVER BASIN UNDER THE EFFECT OF CLIMATE CHANGE

Abstract

 This study develops a model to simulate a rainfall-runoff-flood inundation model for evaluating the change in flooding pattern in future climate change using a d4PDF dataset. Considering a concept of total flood management in watershed, distributed water balance model (DWBM) in upstream watershed, and two-dimensional river flow and flood inundation model in the Arakawa River (2DRFA) are linked. Reproductivity of the DWBM runoff at the boundary condition (BC) in the main Arakawa River in 2DRFA is good when 150m size grid are used in DWBM, however it is not good in the other BCs in 2DRFA. For future climate, the output by DWBM and Choryu function were applied to the BC in the main Arakawa River and to other BCs, respectively. The present risk also exists in the Yoshimi and Kawajima Town as is similar to the situation after the Arakawa-seisen (river course change), however the risk in main river itself is decreased. In future climate, the inundation water depth in both towns are increased and the inundation pattern around Irumagwa and Arakawa River appears. It is more similar to the situation after the Arakawa-seisen in Edo Era.