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Probable impacts of climate change on water resources are a great concern for hydrologists, water managers and policy makers. Global warming and climate change is expected to change the water availability. Using physically based hydrological model Soil and Water Assessment Tool (SWAT), this study assessed the sensitivity of streamflow to individual and combined changes in temperature and rainfall for the Yass River catchment of south eastern Australia. This study also predicted the change in streamflow based on three climate scenarios (B1, A1B, A2) of Intergovernmental Panel on Climate Change Special Report on Emission Scenarios and average of four general circulation models (CNRM-CM3, CSIRO-MK3.5, ECHam5 and MIROC3.2) for three future periods (2030, 2050 and 2090). Streamflow of the Yass River was found to be highly sensitive to both temperature and rainfall changes where 1 % change in rainfall might cause 3-5 % change in streamflow and flow might be reduced up to 16 % for 1 °C rise in temperature. Simulation results based on General Circulation Models (GCM) outputs predicted that the Yass River will likely experience huge change in streamflow due to the impact of climate change. However, due to associated uncertainties regarding climate change scenarios and climate models outputs, the results need to be evaluated carefully before making decisions in future water management and planning. [ABSTRACT FROM AUTHOR]

Abstract: Economic analysis of climate scenarios and alternative water policies is critical for development and implementation of appropriate water policies and programs. Mathematical models have been developed to assess water resources policies due to their ability to explicitly represent the biophysical dynamics of natural systems while integrating these within social and economic constraints. These models have been criticised, however, due to the problems of simplification, overspecialisation, plausibility and lack of empirical validation. This paper introduces a mathematical programming model which uses positive mathematical programming method to calibrate and model agriculture and water use in the Murray-Darling Basin of Australia. This paper reviews the theoretical and technical details of the model development including the key steps taken in collating and scaling the biophysical and economic data, and to address model parameterisation issues. The paper summarises results of an application of the model for assessing climate change impacts in the form of reduced rainfall and water allocations and increased crop water use for agricultural production. The results show the degree of variability in gross values under different climate scenarios compared to the base case scenario, especially in very dry years. The results also show how on-farm adaptation options and water markets can mitigate these losses. [Copyright &y& Elsevier]