A research sub-committee named “Global Environmental Problems and Regional Water Environment” has been organized under Committee on Global Environment, JSCE. This report is the summary of the author's investigation based on the discussion among the members of the subcommittee. The river management for efficient use of river, safety of human life and amenity of river environment results in the reduction of variation of river discharge. The river discharge is a fundamental driving force in the change of the river environment. The stable river discharge reduces the diversity in nature of a river. But the dynamism of a river has to be restricted to maintain human existence. The author discuss the relationship between the nature of a river and the human, the relationship between the conservation of nature and the human existence, recent river works and view points for the assessment of big civil engineering works.
