SEDIMENT YIELD AND SUSPENDED SEDIMENT TRANSPORT IN THE CHIKUGOGAWA RIVER BASIN

Turbidity was measured continuously and suspended sediment samples were collected at the 17 gage stations in the Chikugogawa River basin, the suspended sediment budget and the characteristics of sediment rating curve were studied. The relationship between turbidity and suspended sediment concentration were analyzed for each stream, the nephelometric backscatter became much weaker with steep and small stream. The suspended sediment load was integrated for flood period of 2006, the sediment budget in the whole basin, the reservoir sedimentation by fine solids and the additional sediment supply to the flood water by river bed erosion in the estuarine channel were explained. The sediment rating curve for each stream were developed, it is shown that the coefficients of power function were affected by the watershed conditions such as topography, land use, rainfall and area.