Estimating Bed Load Discharge Using an Acoustic Sensor for Sediment Disaster Prevention

Abstract

This study examined the possibility of estimating bed load discharge using a pipe hydrophone, an acoustic measurement sensor. To that end, a small-scale on-site hydraulic experiment device was built, and regression equations were developed based on the analysis of collision sound signals by bed load discharge, grain size distribution, and flow velocity change. They were classified into pulse and sound pressure integral-based regression equations according to the characteristic value of collision sound. To verify the regression equations, the calculated values of bed load discharge were compared with the actual values. The results showed that the regression equation based on the sound pressure integral had a higher accuracy than the pulse-based regression equation, and the error rate compared to the measured value was approximately 19%. The Index of Agreement (IoA) was found 0.83, indicating a good agreement between the changing trend and estimated value of bed load discharge. It is believed that sediment disasters could be prevented by incorporating various experimental conditions and establishing a corrective relationship with the actual bed load discharge in the river.