RESUSPENSION MECHANISM OF SEDIMENT IN TIDAL OXBOW LAKE WITH ADCP OBSERVATION

Abstract

We conducted observation with acoustic Doppler current profilers (ADCP) in tidal oxbow lake and estimated vertical distribution of turbidity from acoustic backscatter of ADCP. The oxbow is connected to tidal section of the Ishikari River at downstream end. We investigated mechanism of sediment resuspension using estimated turbidity and observation data of ADCP. Accuracy of estimated turbidity is almost in good during this observation. Difference of resuspesion mechanism which depends on balance of tide and wind induced flow is confirmed from observation data. In upstream section of the oxbow, resuspension rate has some correlation to wind velocity. However, in downstream section of the oxbow, sediment resuspension is affected by tide.