河道の変動と災害 ―主として最近における河床変動の実態について―

Abstract

This paper describes the recent trends of the river bed variation at downstream reaches ofthe 1st class rivers in Japan and the several effects of man's activities on the bed variation. Itis pointed out that the trends of the degradation of river bed have been increased since 1960 and go-ing on in recent year, and the river disasters due to the bed degradation are a serious probleminjapan. As an example of the trends of the river, the annual changes of river bed variation and theamounts of the sedimentation at dams and gravel mining in Sh6 River are discussed in detail.