2022 Fiscal Year Final Research Report

Climate change adaptation measures for internal flooding in small and medium-sized cities considering rainwater storage potential

Research Project

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Project/Area Number	19H02407
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 25030:Disaster prevention engineering-related
Research Institution	Shimane University
Principal Investigator	YAJIMA HIROSHI 島根大学, 学術研究院環境システム科学系, 教授 (10283970)
Co-Investigator(Kenkyū-buntansha)	川池健司京都大学, 防災研究所, 教授 (10346934) 吉岡有美島根大学, 学術研究院環境システム科学系, 助教 (40753885) KIM SANGYEOB 島根大学, 学術研究院環境システム科学系, 助教 (50797826)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	内水氾濫 / 雨水貯留ポテンシャル / 貯留施設 / 気候変動
Outline of Final Research Achievements	In Matsue City, Shimane Prefecture, many small and medium-sized rivers are connected to Lake Shinji or the Ohashi River, which inhibits the natural flow of rivers and causes internal flooding about once every few years. To reduce internal flooding, increasing the rainwater storage (referred to as "rainwater storage potential" in this study) by utilizing rice paddies, ponds, etc., around the urban area is considered effective. The results of this study using an internal flooding model that considers the city's sewerage network showed that utilizing approximately 70% of the rainwater storage potential can significantly reduce the flood damage caused in July 2006, which was the most devastating in recent years.
Free Research Field	水工水理学
Academic Significance and Societal Importance of the Research Achievements	近年大雨に伴う被害は、河川の氾濫すなわち外水による被害だけでなく、市街地の雨水排除能力超過による内水被害も深刻になってきている。本研究により、内水氾濫を防ぐためには、市街地周辺に存在する田んぼやため池を活用し、都市域の雨水貯留効果を増大することが内水氾濫抑制の有効な手段になり得ることを示した。今後、市街地においては、周辺の土地利用規制を含めた雨水貯留が可能な区域の保全を図ることで、気候変動による内水氾濫被害の拡大を防ぐことが可能となると考えられた。