Abstract
Purpose of this paper is to examine logic of knowledge and exchange of resident (community) through a historical process of concerned actors' relationship on property, management and utilization of Yahagi river basin in Aichi Prefecture. The analysis focuses on changes and interactions among river fisheries cooperative association which was not traditionally considered to be an actor of river environment conservation, agricultural group that has superior rights on irrigation and drainage of river, government as the river administrator, and citizens' group appeared in the eighties and showed strong interests in environment conservation. The results reveal the formation process of new open community which started with environmentalization of river in the nineties which let various actors' activities open to river basin society and by interacting with others, boundary actors, used to stay inside of immobilized boundary of each community, turned into relational actors to develop loose ties with other actors.
