CHANGES OF TONEGAWA RIVER CHANNEL BY RIVER IMPROVEMENT SINCE THE MElJI ERA AND HYDROSCIENCE AND HYDRAULIC ENGINEERING ANALYSIS ON ITS FACTOR

Abstract

The Tonegawa river is the largest river in JAPAN. The river channel has been improved from the MEIJI era for protecting the people from the flood and for maintaining the navigation route for the cargo shipment.

We have clarified the historical flood that had greatly influenced on the formation of present river channel. The idea on the planned river improvement based on that historical flood and the progress of this improvement have also been clarified. This paper has shown the process of the Tonegawa river channel formation and indicated one of the directions of future river improvement.