Regional patterns of erosion and sediment and nutrient transport in the Goulburn and Broken River catchments, Victoria

A project conducted as part of a National Land and Water Resources Audit (NLWRA) project for disseminating NLWRA nutrient and sediment budget information to catchment management agencies used SedNet modelling to determine the delivery of sediment and nutrients within the combined Goulburn and Broken River catchments, Vic. Specific objectives were to: use the best available regional data sources and improve techniques to get a more accurate result for the catchments, to compare results with monitored sediment and nutrient loads, to examine the time sequence of loads and to demonstrate how mean annual loads can be disaggregated into daily loads, and to develop the ability to examine future management scenarios and their affect on sediment and nutrient export from catchments. The results predict that each erosion process (surface wash, gully erosion and riverbank erosion) is significant and that the processes are highly focused, with much of the sediment and nutrients being generated by relatively small areas. It is argued the results can be used to guide further investigation, and to identify areas for improved management and setting targets for catchment restoration.