Acoustic measurements of clay-size particles.

Knowledge of sediment concentration is important in the study of streams and rivers. The work presented explores using high frequency (20 MHz) acoustic signal attenuation to measure the concentration of fine sediment particles (0.2-5.0 microm) in a fluvial environment. A small laboratory tank with a pitch-catch transducer configuration measured a 35 dB change in signal level over a wide range of kaolinite and bentonite concentrations (1-14 g/l) over a range of distances (180-357 mm). The data suggest that a fixed distance of 180 mm between the transducers will be capable of measuring the entire range of concentrations.