Abstract
Continuous measurement of flow rate has been carried out in an especially shallow and wide gravel-bed river (water depth 0.6 m at low-flow conditions and width 115 m) using FluvialAcoustic Tomography System (FATS) with a couple of 25 kHz broadband omni-directional transducers (0.05 m diameter). The reciprocal sound transmissions were performed between the two acoustic stations located diagonally on both sides of the river. In addition to the flow rate, cross-sectional average temperature were deduced from the sound speed data collected by the FATS. A maximum relative difference between FATS and rating curve estimates was approximately 30%. The rating curve method underestimated short-term variations of the flow rate. FATS successfully measured the cross-sectional average temperature. Spectra of velocity and flow rate were estimated in wide frequency range.
