混住地域における用水路管理の再編過程

—— 香川県丸亀市における「いでざらい」を事例に ——

抄録

　　　The purpose of this paper is to clarify how irrigation canals are co-managed among irrigation associations and new residents. Irrigation canals have traditionally been characterized as “tight commons” (Inoue, 1997) managed and used by villages and irrigation associations. However, as new residents moved into the rural area and irrigation canals began to have a domestic wastewater function, new residents became involved in some of the irrigation canals management.
　　　Based on this awareness of these issues, we conducted an analysis based on interviews and participant observation and an account book of the irrigation association using a case study of irrigation channel cleaning in Marugame City, Kagawa Prefecture, which has been plagued by drought since ancient times and retains severe water use practices.
　　　 As a result, the following findings were revealed. The irrigation association allowed various degrees of commitment and involvement of new residents, depending on the relationship between the residents and the irrigation channel. The tight canal management, which had imposed strict obligations on members, was restructured to a flexible mechanism that include diverse new residents with various residential purpose and migration dates.