Sediment and nutrient sources and sinks in a wet-dry tropical catchment draining to the Great Barrier Reef

Many tropical river systems have altered water quality due to human land use, impacting the biodiversity of freshwater and coastal ecosystems. Long-term, catchment-scale monitoring is needed to understand pollutant sources, controls, and trends. This 12-year study monitored baseflow and flood event nutrient and sediment concentrations, and estimated sediment loads across the Normanby Basin in northern Australia. Suspended sediment concentrations and yields were highest in upper catchment areas where cattle grazing occurred on erosion-prone sodic soils. Mid- and lower catchment rivers and floodplains were a sink for sediments and nutrients, trapping around 75% of suspended sediments during events. Clays (