151. Estimation of possible climate change impacts on water availability, extreme flow events and soil moisture in the Goulburn and Ovens Basins, Victoria
- Author
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Schreider, S. Yu, Jakeman, A.J., Pittock, A.B., and Whetton, P.H.
- Subjects
Victoria -- Environmental aspects ,Climatic changes -- Environmental aspects ,Soil moisture -- Environmental aspects ,Streamflow -- Environmental aspects ,Earth sciences - Abstract
A rainfall-runoff model (IHACRES) is applied on a daily timestep to a large area of the state of Victoria, Australia. Successful calibrations of this dynamic lumped parameter model were performed for 5 rivers contributing streamflow to the Ovens Basin, and for 9 rivers of the Goulbum Basin. This is the first application of the model on such a scale, involving two basins where the total drainage area of the catchments modelled is about 6,500 [km.sup.2]. The models were tested by simulation over the entire common period of observation for the 14 catchments under consideration. The results show that the models closely simulate the observed streamflow. The effect of historical climate variability on streamflow was investigated. The models were used for estimation of the potential impact of climatic change on water availability for irrigation for different climate scenarios developed in the Division of Atmospheric Research, CSIRO. This allows conditional estimates to be made of water supply in these basins for the periods 2030 and 2070 under current vegetation conditions. Projecting the future hydrologic regime in this region is extremely important, in particular for supporting irrigation management of the Basin. The problem of estimating the impact of climate change on the probability of extreme events of the hydrological regime was analysed. Flood frequency was found to increase for the scenarios providing the maximum amount of water; to 50% at 2030 and 100% at 2070. The probability of flood events for the 'dry' scenarios rapidly decreases for these dates. Drought frequency, as defined by a soil wetness index, increased 35% for the 'dry' scenario at 2030 and 80% for this scenario at 2070.
- Published
- 1996