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 of achieving a range of sediment reduction targets were estimated for a number of locations. Four investment prioritization scenarios were tested to identify the most cost-effective strategy to control suspended sediment loads. The impacts of spatial heterogeneity of sediment transport and varying the spatial scale of target locations on cost effectiveness were examined. The results show that: 1) an optimum solution of costeffective sediment control can be determined through the spatial sediment budget; 2) appropriate investment prioritization can offer potential large cost savings as the magnitude of the costs can vary by several times depending on what type of erosion source or sediment delivery is targeted; 3) target settings which only consider the erosion source rates can potentially result in spending more money than random management intervention; and 4) prioritization becomes a more cost effective strategy as the area considered increases because of the spatial heterogeneity of contributing sediment. An interpretation of the non-linear cost to increasing sediment reduction relationship is also provided.