Sediment Transfer through the Fluvial System (Proceedings of a symposium held in Moscow, August 2004). IAHS Publ. 288, 2004, 245–252

1 CSIRO Land and Water, GPO Box 1666, Canberra, ACT 2601, Australia

2 Land & Water Australia, GPO Box 2182, Canberra, ACT 2601, Australia

3 Institute of Geography, Schneiderberg 50, D-30167 Hanover, Germany

Abstract The Murray-Darling Basin in the southeast of Australia covers approx. 1 × 10⁶ km², equivalent to 14% of the country’s total area. Accelerated erosion, primarily in upland regions, has greatly degraded river habitats over the past century. Here we describe the results from the basin-wide sediment modelling for this region using SedNet: a spatially distributed sediment routing model which predicts sediment loads, together with bed, flood plain and reservoir deposition. Comparisons are made between current (past 100 years) and natural (pre-European) conditions. The results demonstrate that the basin is one of sediment redistribution rather than net sediment export. The basin is estimated to have 18% of rivers with >100 times natural loads. Erosion of gullies and riverbanks has also resulted in 11 000 km (13% of the total) to have historical accumulation of over 0.3 m of sand and gravel averaged over the river length.

Key words erosion; Murray-Darling Basin, Australia; sediment budget; sediment load; spatial model