Bedload measurement by acoustic energy with Hydrophone for high sediment transport rate

Abstract

Hydrophone has been used to measure bedload transport intensity by counting the number of pulses made by hitting of sand and gravels to a steel pipe. When sediment transport rate is high, the sound level is continuously high and never drops low resulting in that the number of counting becomes low or zero. Sound level is recorded to know sediment transport intensity instead of pulses when sediment transport rate is high. The method was adopted in the Waru-dani torrent, a branch of the Jinzu River. The relationship between acoustic energy and pulses were analyzed. The acoustic energy was well recorded and showed sediment transport intensity as well as the record of pulses. It was found that there is an appropriate amplification. As we have not obtained good data for high sediment transport rate, we will continue the measurement.