Keiji TAMURA, Yasukazu KOSUGE, Taro UCHIDA, Yoko NAGATA, Ken’ichirou KOSUGI and Takahisa MIZUYAMA
Suspended sediment in mountain rivers can be observed using two methods: one measures the suspended sediment concentration directly by sampling the water; the other is indirect measurement using a turbidity meter. The results of this study are as follows. 1) The turbidity meter can only measure the wash load (particle size<0.106mm). 2) Although the suspended sediment can be easily observed by bucket sampling of water, which is also suitable for ascertaining the characteristics of the wash load, this method is not suitable for continuous monitoring. In contrast, observations obtained with a turbidity meter can be used for continuous monitoring and are appropriate for monitoring the basin but are not suitable for obtaining stable data. 3) It is important to observe the concentration distribution of suspended sediment in the vertical direction by using multistage suspended sediment samplers for a variety of considerations.
Key wordsFmountain rivers, suspended sediment observation, turbidity meter, direct water sampling, suspended sediment concentration distribution