抄録
The aim of this contribution is to monitor unsteady behavior of streamflow, as well as, loops of streamflow-stage in a relatively small mountainous river. In order to determine river discharge, two methods were used: (i) the continuous slope area method (CSA), and (ii) the Index Velocity Rating Curve discharge data obtained by means of a novel fluvial acoustic tomography system (FATS) which developed by Hiroshima University. The findings showed that during a single hydological event, the temporal variations in water slope has two peaks, and water slope-stage has a positive hysteresis behavior. In addition, streamflow-stage hysteresis loops estimated by FATS are informative more than streamflow-stages estimated by the CSA method. Additionally, it was confirmed that stramflow-stage hysteresis loop increases with large-scale rainfall events.