ACOUSTIC INVESTIGATIONS OF TIDAL BORES IN QIANTANG RIVER

The continuous measurements of flow velocity/rate and suspended sediment concentration (SSC) in tidal rivers are crucial in estuarine studies. However, the accurate estimates of these terms are difficult and labor-intensive procedures are needed; thus, a robust and efficient method of the measurements is required. The changes of cross-sectional average suspended sediment concentration, tidal bore celerity and flow velocity were measured in the Qiantang River by using acoustic tomography systems. The results showed that the amount of SSC increased more than threefold during tidal bores. The acoustic systems could successfully measure the cross-sectional average velocity in the unsteady flows though the high SSC bred a short missing period after the bore arrival.