In the previous studies, SS concentration is found to be associated with rainfall intensity by using exponential function. However, it is not clarified how high turbidity is provided from fields and forests areas. Therefore production and transportation of suspended sediment was investigated by sampling surface soils in 18 domains over an entire river basin. Chemical decomposition analysis showed that the transportation rate of suspended sediment was related to the type surface soil. Turbidity measurement in fields and forests and chemical decomposition analysis enables to develop a method which can be used for the evaluation of the relative suspended sediment transportation rates from each domain of a river basin to its downstream end.
