2022 Fiscal Year Final Research Report

Geographical study on Prompt land use changes on riverside land from the viewpoint of dynamics of physical and social environment along the middle Arakawa river, Saitama, Japan

Research Project

PDF

Project/Area Number	18K01128
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 04010:Geography-related
Research Institution	Rissho University
Principal Investigator	Shimazu Hiroshi 立正大学, 地球環境科学部, 教授 (90251909)
Co-Investigator(Kenkyū-buntansha)	鈴木重雄駒澤大学, 文学部, 准教授 (40581476) 宇津川喬子法政大学, 文学部, 助教 (20822711) 本岡拓哉立正大学, 地球環境科学部, 特任講師 (60514867) 伊藤徹哉立正大学, 地球環境科学部, 教授 (20408991) 横山貴史立正大学, 地球環境科学部, 特任講師 (70710151) 原将也神戸大学, 人間発達環境学研究科, 助教 (00823147) 原美登里立正大学, 地球環境科学部, 准教授 (00386517)
Project Period (FY)	2018-04-01 – 2023-03-31
Keywords	河川堤外地 / 自然 / 堆積環境 / 災害 / 植生 / 土地利用 / 不法占有 / 名取川
Outline of Final Research Achievements	The nature, the influence of the river, flood disasters, traditional land use, and the relationship between present land use and landowner involvement were studied on the riverside land of the lower Natori River that flows down the Sendai Plain and the Arakawa River in Saitama Prefecture. From the sediments and vegetation surveys, it became clear that sedimentation had been repeated many times on the riverside land, and alien plants had invaded according to the micro landforms due to the abandonment of cultivation. During the research period, although the severe flood caused by Typhoon No. 19 in 2019 caused sedimentation in the lower riverside land of the Natori River, inundation of about 2m in the higher riverside land, and woody debris deposition, cultivation continued on private land. It has also become clear that there have been changes in the use of agricultural land and that cultivation has been carried out by illegal occupation on land of the understate management.
Free Research Field	地理学
Academic Significance and Societal Importance of the Research Achievements	河川堤外地は一般的には公有地となっているが、仙台平野の名取川下流と埼玉県の荒川中流では築堤前からの土地所有が継続され、私有地として耕作が行われてきた。都市内にありながら、洪水による自然プロセスが働く場である河川堤外地において、微地形と洪水発生時の地形変化や堆積環境の関係、植生の特徴や耕作放棄にともなう外来種の侵入、土地利用や土地所有の実態と変化、洪水への対応、不法占有の実態や不法状態の高度化が明らかになったことは、学術的に意義がある。また、都市内にわずかに残る自然環境や災害の特徴と土地への影響、不法占有の状況を明らかにできたことは、これからの河川管理や防災を考えるうえで重要な社会的意義がある。