Sediment concentration measurement using ADCP in a large river: Evaluation of acoustic frequency and grain size

Acoustic principles appear as one of the main surrogate technologies to quantify sediment transport in large rivers, which also allows simultaneous quantification of flow, both at high spatial and temporal resolutions. While there are a large number of works dealing with this subject, further studies are necessary under natural conditions, particularly with complex grain size distributions at the cross section and under different water stages. This paper aims to evaluate this technology in a large river under different conditions of suspended sediments (i.e. grain size and washload/suspended sand ratios). For this objective, suspended sediment data were obtained with traditional methods at zones with different suspended sediment characteristics and water stages. Simultaneously, the acoustic signal was measured with two ADCP frequencies (600 and 1200 kHz). Different parameters and variables involved in the acoustic theory are analyzed. Finally, a discussion of the knowledge gaps that must be addressed in future research is presented.