The application of conceptual modelling approach to evaluate the impacts of climate change on the future streamflow in three unregulated catchments of the Australian hydrologic reference stations

Abstract

The future climate-change impacts on streamflow variability at three-contributing catchments of the Australian-hydrologic-reference-stations (HRSs), Harvey, Beardy and Goulburn catchments, are presented in this study. Observed hydro-meteorological data from the contributing-catchments were used to calibrate and validate the HBV-hydrological-model before the streamflow prediction. The downscaled future rainfall and temperature from a multi-model ensemble of eight-GCMs of the CMIP5 under two representative-concentration-pathways RCP4.5 and RCP8.5 were used to run the calibrated HBV-model to simulate the future daily streamflow at the three-HRSs. Nearly all GCMs predict reduction-tendencies in annual mean rainfall and an increase in temperature and potential evaporation across the studied catchments during the mid (2046-2065) and late (2080-2099) of the 21st-century. The annual mean streamflow across the three-catchments also tend to decrease during the future periods under the two climate scenarios and ranged between 31-60% for the Harvey-catchment, 1-24% for the Beardy-catchment and 18-42% for the Goulburn-catchment relative to the control-run.