Estimating suspended sediment concentration using an acoustic doppler velocimeter

Abstract

The evaluation of suspended sediment concentration (SSC) still represents a challenging task, associated with experimental processes composed of several stages. This paper aims to contribute to the evaluation of the potential use of the acoustic Doppler velocimeter (ADV) to quantify SSC. This equipment can represent a faster and more economical alternative to SSC evaluation. It is also sought to verify the sensitivity of the equipment in the distinction of particles size. A laboratory measurement system was developed, characterized by a cylindrical container 30 cm in diameter and 30 cm high, connected to a pumping system. This system allowed the mixing and homogenization of different proportions of water + soil, generating samples of known characteristics, for later evaluation with ADV. Samples with eight SSC and five particle sizes of five soil types were performed, totaling 200 tested configurations. For each test, three samples were collected, totaling 600.  For data visualization and post processing, the WinADV program was used, applying the PSTM filter. The results obtained indicated the increase of the SNR (signal-to-noise ratio) obtained with the ADV with the addition of SSC for the different soil types for the five granulometries, with the best correlations between the echo and SSC in soil trials 2, 3 and 4. In the present study, the granulometric range does not interfere with the ADV readings. This study demonstrates that there are good prospects for the use of ADV for the quantification of SSC, but emphasizes the importance of complementary studies.