Sediment classification and estimation of suspended sediment fluxes in theChangjiang Estuary, China

Estuarine suspended sediment is transported in a mixed nonuniform way under unsteady flows. Sediment of different grain sizes has different characteri stics and transport behavior and has a different effect on the ecological s ystem. Therefore classification and fractionization of the mixed sediment a re required before the flux is estimated. A fuzzy clustering approach is ap plied to the classification of suspended fine-grained sediment in the Chang jiang Estuary. Two populations are objectively found by considering the sta ndard grain-size distribution statistics of each cluster. The critical grai n size of similar to 10 mum in diameter is the size limit for cohesive sedi ments. A grid with equal cell areas is used to estimate fractional sediment fluxes through an estuarine cross section since this type of grid introduc es less statistical error in the flux calculation. The sediment transport m echanism is analyzed.