Development of a flood risk assessment method due to multiple hazards of storm surge, high wave, and river-flow

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05046
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Kumamoto University
• Principal Investigator: Kim Sooyoul 熊本大学, くまもと水循環・減災研究教育センター, 准教授 (60508696)
• Co-Investigator(Kenkyū-buntansha): 間瀬 肇 京都大学, 防災研究所, 名誉教授 (30127138) ; 森 信人 京都大学, 防災研究所, 教授 (90371476)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 複合災害 / 高潮 / 高波 / 豪雨 / 浸水

Outline of Final Research Achievements

A coupled model of surge, tide, and river flow was developed and applied to Osaka Bay for Typhoon Jebi 2018. It was found that the difference of 1.2 m in the sea surface level between Kema and the river mouth occurred in Yodo River and Ina River. Also, a coupled model of surge, tide, wave, wave overtopping/runup, precipitation, and reverse flow from a sewer system was developed and applied to Nemuro in Hokkaido. It was clarified that the developed model has applicability based on comparisons of the model results with survey ones. Then, the model was applied to the Kansai International Airport to estimate floods due to Typhoon Jebi 2018. As a result, the model is able to calculate the floods due to individual factors of the reverse flow from the sewer system, the wave overtopping/runup, and both.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

従来の高潮モデルは日沿岸の防波堤の高さを決定する際に良く用いられた手法であり，近年までに様々な精度向上が行われた．しかし，浸水想定図や堤防の高さを決める時になるべく現実に近い精度を持つ数値モデルを用いるのは良い．従来の高潮浸水モデルに含まれてないのは同時生起する高波による越波・打上げ，河川流量である．国内の研究では越波・打上げを考慮して高潮浸水を研究するのは１グループである．海外の研究でもグループの数は少ない．本研究は国内・国外の最先端研究であり，開発した「高潮・高波・越波・打上げ・浸水・下水道の逆流・河川結合モデル」は今後気候変動を踏まえた複合災害の推算・評価に関する研究の基礎研究になる．