Spatially Distributed Investment Prioritization for Sediment Control over the Murray Darling Basin, Australia

Based on a spatially-distributed sediment budget across the Murray Darling Basin, costs ofachieving a range of sediment reduction targets were estimated for a number of locations. Four investmentprioritization scenarios were tested to identify the most cost-effective strategy to control suspended sedimentloads. The impacts of spatial heterogeneity of sediment transport and varying the spatial scale of targetlocations on cost effectiveness were examined. The results show that: 1) an optimum solution of costeffectivesediment control can be determined through the spatial sediment budget; 2) appropriateinvestment prioritization can offer potential large cost savings as the magnitude of the costs can vary byseveral times depending on what type of erosion source or sediment delivery is targeted; 3) target settingswhich only consider the erosion source rates can potentially result in spending more money than randommanagement intervention; and 4) prioritization becomes a more cost effective strategy as the areaconsidered increases because of the spatial heterogeneity of contributing sediment. An interpretation of thenon-linear cost to increasing sediment reduction relationship is also provided.