MEASUREMENT OF BED LOAD USING HYDROPHONES IN HYDRAULIC MODEL EXPERIMENTS

Abstract

Recently, in order to obtain basic data for the integrated management of the sediment transport in a river basin, several monitoring of the bed load by indirect estimation in actual rivers called the hydrophone method have been conducted and examined for practical use. In hydraulic model experiments to evaluate the function and efficiency of installing sabo facilities in rivers, the bed load is measured by trapping directly the sediment using boxes, sieves, etc.
In the present study, we measured the temporal variations of pulse counts reflected from collisions the sediment particles with the various shapes of hydrophones which are laid in a rectangular channel. We then compared the results of the measurement of bed load at the downstream end of the geometric model by means of hydrophones with those obtained from the conventional way of measuring bed load by using sieve. As a result, it has been confirmed that the results of actually measured bed load are in good agreement with those obtained from pulses by mean of hydrophones and therefore that hydrophone is indeed applicable to hydraulic model experiments.