A sluggish recovery: the indelible marks of landuse change in the Loddon River catchment

The upper Loddon River Catchment is characterised by a complex geomorphology confused by the historical legacies of mining, clearing for agriculture and dam construction. This paper describes the processes acting on the catchment to erode the landscape and deliver sediments to the stream network. Our assessment of catchment processes is based on field observations and interpretation of a catchment scale sediment budget – developed through application of the geomorphic process model, SedNet. Gully erosion has been the most important source of sediment input to the Loddon River (84 % of sediment yield) with low combined sediment input from hillslopes and bank erosion (16%). Although the Loddon Catchment’s sediment yield, per unit catchment area, is typical for southern Murray-Darling Basin (MDB) catchments and similar to the national average, the amount of sediment derived from gully erosion is some 50 % more than the national average. Only a very small proportion of the sediment mobilised is exported from the study area. Of the sediment that remains, about half is permanently stored in reservoirs or on floodplains with the rest stored as bedload in stream channels. Most of inchannel sediment stores are sand – that we classified as potentially mobile sand slugs. We predict that approximately 50 % of stream length is impacted by sand slugs or similar instrea