Analysis of an integrated model for assessing land and water policy options

This paper outlines results of a sensitivity analysis on a model developed to examine water policy and land use change options in the Yass River catchment, NSW. The model has three integrated components consisting of policy, hydrological and agricultural production system models. The sensitivity analysis involved running variables in the model over a broad range of values to examine the response of model outputs. For ease of interpretation, three indicators were used to examine the model output: the number of zero flow days; the median of non-zero flows; agricultural profit. The analysis shows that the model is sensitive to changes in inputs to all component models. But the sensitivity of the model varies depending on whether the input selected has a direct or indirect effect on other system components. Sensitivity analysis of the integrated model illustrates the response of the integrated model when assessing those land and water policy options selected for analysis, and highlights the plausibility of the model results and limitations in applying the model as a decision support tool for policy analysis.