| Continuous monitoring of suspended sediment discharge in tidal compartment of river is important for management of river environment in estuary. In recent years、 many studies about calculation of turbidity from echo intensity of Acoustic Doppler Current Profiler (ADCP) had been conducted in rivers and bay areas. This method can get both flow and suspended sediment discharge at the same time. However、 there are few study cases to apply this method on monthly basis of turbidity estimation、 which are needed to practical river management. We tried to apply ADCP for obtaining long-term time series turbidity profile. We analyzed observation data of ADCP in tidal compartment of actual river for one month. Acoustic Backscattering Turbidity (ABT) was calculated from echo intensity data of ADCP and compared with observed turbidity using turbid meter. ABT was generally adapted to observed turbidity. It means this method can reproduce long term turbidity profile approximately in actual river in tidal compartment. We also investigated relation of time series of turbidity distribution and external factor、 such as wind velocity、 wind direction and small flood. Mechanism of turbidity change caused by external factors could be clarified in this study. Further investigation should be needed under severe conditions to clarify accuracy and compatibility of this method. |
