DYNAMICS OF THE TURBIDITY MAXIMUM IN THE FLY RIVER ESTUARY, PAPUA-NEW-GUINEA

Field studies in the Fly River estuary, Papua New Guinea, show that the turbidity maximum exists only at spring tides. The wind is important in wave-driven fluidization of the bed. The erosion rate varies with the sixth power of the water velocity. The suspended sediment settling velocity varies nonlinearly with the concentration. At least three-quarters of the river sediment inflow appears to be trapped in the estuary. A numerical hydrodynamics-sediment transport model is able to reproduce a number of the key features of the turbidity maximum, and suggests that the turbidity maximum is due to the simultaneous influence of the baroclinic circulation and the tidal pumping.