ABSTRACT
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Discharge Characteristics of the Central GBR Region . . . . . . . . . . . . . . . . . . . . . 146 Modelling River Plumes in the Central GBR Region . . . . . . . . . . . . . . . . . . . . . . 147 Simulating the 1981 Flood Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Simulating the 1974 Flood Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Simulating the 1991 Flood Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Simulating the 1972 Flood Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Simulating the 1979 Flood Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Minimum Salinity Analysis of Moderate Burdekin Floods . . . . . . . . . . . . . . . . . 153 Plume Intrusions in the Cairns Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Rivers collect the freshwater runoff from the land and deliver it to the sea at the coast. The runoff also collects and carries sediment, nutrients, and contaminants depending on the catchment characteristics and land uses. Once discharged from the river, the runoff drives a buoyant plume into coastal and shelf waters. The plume eventually spreads and mixes and moves around with the winds and currents. This mixing with ambient coastal waters will ultimately dilute the runoff plume as well as any concentrations of sediments, nutrients, and contaminants carried within the plume. In the wet and dry tropical catchments adjoining the Great Barrier Reef (GBR), river discharges are highly seasonal and usually event-driven in nature and result from rainfall events associated with evolving monsoon troughs or passing tropical cyclones (Wolanski, 1994).
