Uncertainties in River Flow Measurements Using Acoustic Tomography: Potentials and Challenges

Providing precise records of streamflow measurements, mainly during floods, is essential for understanding the evolution dynamics of river channels, projecting future flow records, and introducing best management plans. In some cases, conventional measurement methods fail to provide reliable estimates of streamflow data during unsteady flow conditions. Recently, underwater acoustics tomography-based methods have been considered as promising potential to provide accurate river flow measurements. The objective of this work is to investigate the potential of a new generation of acoustic tomographic system designed to overcome challenges associated with accurate river flow measurement in restricted river geometries. In particular, we aim to monitor accurate streamflow within a narrow and extremely shallow river. The utilized system employs acoustic signals to map the sound speed across the entire river cross-section, and thus enables accurate and continuous measurements of the cross-sectional average velocity and river flow. The findings showed that the utilized system can be operated within extremely shallow depths > 10 cm, Interestingly, the flow estimated by the FAT system was very comparable with other reference datasets obtained by additional independent methods, especially, during high flow conditions. However, the presence of high sediment particles generated during flood events weakened the quality of acoustic signals which resulted in measurement failures during these periods.