Sediment fluxes and sinks for Magela Creek, Northern Territory, Australia

Sediment fluxes and sinks based on total sediment load for Magela Creek in the Australian wet–dry tropics have been constructed from detailed measurements of stream suspended sediment (turbidity and suspended sand) and bed load for the 10-year period, 2001–2002 to 2010–2011. This work shows that the sediment trap efficiency of the vegetated wetlands on lower Magela is high at ~89.5%. Sediment fluxes are the lowest in the world because of low soil erosion rates and because upstream floodplains and downstream wetlands trap and store sediment. Bedload yields are less than suspended sediment yields, but the amount of silt and clay is much less than the amount of sand (suspended sand and bedload). All sand is stored upstream of the East Alligator River. Downstream connectivity of sediment movement does not occur. Therefore, sediment moves discontinuously from the upper to the lower catchment.