Abstract
This paper describes a method of measuring flow rate and size distribution of sediment transported in gravel-bed river during small flood. The device developed is inexpensive, compact and can be installed in the river bed by hand. A steel shell covers the device and impact sound when sediment hits the steel shell is recorded by a digital sound recorder stored in the steel shell. The relationship between sound wave profile and a diameter of the impinged sediment particle was validated based on the result of flume experiment. The proposed method was used to measure processes of sediment transport during a flushing flow released from a dam, then the size distribution and amount of bed-load were successfully analyzed.
