TEMPORAL-SPATIAL DISTRIBUTION OF VELOCITY IN AN ACTUAL RIVER REVEALED WITH MULTIPLE VELOCITY MEASUREMENT METHODS

Abstract

 This study aims to reveal temporal-spatial distribution of velocity in an actual river to clarify how to treat fluctuation in terms of stable accuracy of discharge observation. Simultaneous velocity measurements were conducted with radio wave current meter, ADCP and PIV. Time-series of velocities on water surface and underwater were analyzed, indicated that variation converges with 60 seconds of average time. Furthermore, vertical distribution of velocity is consistent with the Aki’s equation which gave coefficient of float. Besides, PIV analysis was conducted in order to obtain spatial distribution of water surface velocity. The velocity was compared with velocity by radio wave current meter, which showed a reasonable agreement. Based on the analysis above, discharge values with some measurement methods were calculated.