山地流域における出水と土砂流出(3) ―穂高砂防観測所の観測結果―

Abstract

The authors carried out some observation on the runoff, sediment yield and transport in asmall mountain watershed, called Hirudani Experimental Watershed, which is a tributary of theJintsu River in Gifu Prefecture, Japan. This paper presents some results of the observations onrunoff characteristics, on rate of sediment yield and transport by petrologic classification of gravels, settled and transported, and of the survey on the change of river bed before and after floods.The following interesting fact are pointed Out after studing the observations and surveyresults.1) The characteristics of transport materials reflect the process of the runoff over the sedimentsource areas.2) The process of the sediment transport in a mountain watershed is revealed throughthe distribution of the grain size and petrologic character of gravels in the transport materials.3) The river bed variations as well as the sediment yield should be detected for estimationof the sediment discharge from a basin.