ABSTRACT
We developed a bedload measurement method based on the acoustic Doppler current profiler (ADCP) and real time kinematic global positioning system (RTK-GPS), and we applied it in Japanese rivers during floods. Moreover, we observed suspended sediment using acoustic backscatter obtained by the ADCP. For this paper, to clarify the sediment transportation in large rivers where suspended sediment is dominant during flooding, we performed the following tasks in the Brahmaputra River in Bangladesh: we observed floods using a manned boat equipped with ADCP and RTK-GPS, measured turbidity, and sampled the water. The results show that the ratio of bedload discharge to suspended sediment discharge was within a range of 10–25 times during a discharge condition of 38,000–63,000 m3/s.
