34. Recent Trend in Turbidity and Suspended Sediment Loads in the Murrumbidgee River, NSW, Australia

Turbidity and flow data from the Murrumbidgee River, NSW Australia were used to assess if changes in land management have altered suspended sediment loads. The data indicate that over the last 20 years the turbidity and sediment load per unit volume of flow has decreased significantly. The decrease in the sediment load is related to a number of factors, including: (a) a decrease in flow from the tributary catchment; (b) an increase in the proportion of water derived from upstream water storage; (c) a decrease in the total volume of flow in the main channel; (d) stabilization of > 50% of the gully network; (e) an increase in the extent of in-stream wetlands; and (f) a massive increase in the number of farm dams. The work illustrates the difficulty in relating changes in sediment loads in large rivers to causal factors.