2003 年 9 巻 p. 225-229
We discuss the performance of the ultrasonic flow velocimeter in flood by field observation in Uono River, Central Japan. In effect, the ultrasonic flow velocimeter yielded stable measurement results for velocity less than 2.5m/s. We found that the lack of records were caused by impulsive noise resulted from bubble. And we also found that impulsive noises prevented detecting acoustic signals, even if the acoustic signal was transmitted. In order to apply the ultrasonic flow velocimeter to flood measurement, it is effective to reduce the influence of noise.