Hydroclimate projections for Victoria at 2040 and 2065

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Potter, Nick ORCID ID icon; Chiew, Francis; Zheng, Hongxing; Ekstrom, Marie; Zhang, Lu ORCID ID icon


2016-12-01


Report


51 p


Key findings This report presents hydroclimate projections for Victoria for 20 year periods centred around 2040 and 2065, prepared through the Victorian Climate Initiative (VicCI) for the Victorian Department of Environment, Land, Water Planning (DELWP). The projections are based on the latest generation of global climate models (CMIP5) replacing the CMIP3 models that provided the change information for previous regional runoff projections prepared by the South East Australian Climate Initiative (SEACI) (Post et al., 2012). The large majority of CMIP5 models, like the CMIP3 models, indicate rainfall declines across Victoria, which will be amplified in the runoff. Compared to the 2060 SEACI results (Post et al., 2012), the median projected change in runoff at 2065 is about 1/3 less dry in most cases, with a slightly larger range of results (in terms of the 10th and 90th percentile changes). This is primarily a direct response to the somewhat less dry regional rainfall projection from CMIP5 models relative to the CMIP3 models (CSIRO and Bureau of Meteorology, 2015, Figures A.2 and 7.2.5; Figure 9 and Figure 11). The spatial pattern of rainfall changes at 2040 and 2065 (Figure 9 and Figure 11) is similar, with the response enhanced (i.e. more wet or dry) by 2065. The low-impact scenario has increases in rainfall over most of the study region, but with little to no increase in rainfall in the south-western part of the study region and the main runoff producing areas along the Great Dividing Range in Victoria. The high-impact scenario shows decreases over the entire study region, particularly in the western part. The medium-impact scenario shows some decreases in rainfall over most of Victoria, particularly in the second half of the year (i.e. winter and spring). The projected medium-impact scenario change in regional potential evaporation (Figure 10 and Figure 12) is a 4-6% increase in PET by 2040, and a 6-10% increase by 2065. The PET increase is driven mainly by rising temperatures. Unlike rainfall, the future PET projections are similar across GCMs and with little spatial variability across the region. The spatial pattern of projected changes to runoff broadly follows the spatial pattern for rainfall changes. The medium-impact scenario shows runoff decreases of 5-15% over most of Victoria by 2040 and 10-30% by 2065, with comparatively larger reductions in the south-west. The low impact scenario shows runoff increases over most of Victoria of 5-20% by 2040, reducing to little change by 2065. The high-impact scenario shows runoff decreases of greater than 20% over the entire study region by 2040, and greater than 40% in most regions (and over 50% decrease in runoff in the west), by 2065.


CSIRO


Canberra


Climate Change Processes; Surfacewater Hydrology


http://doi.org/10.4225/08/5889749204faa


[Final] VicCI project 8 report.pdf (pdf) (3.35MB)


https://doi.org/10.4225/08/5892224490e71


This report has been placed on the CSIRO repository and may be made available to persons outside of CSIRO for non commercial purposes, in its entirety and without deletion of disclaimers and copyright information.


EP161427


Client Report (Author)


English


Potter, Nick; Chiew, Francis; Zheng, Hongxing; Ekstrom, Marie; Zhang, Lu. Hydroclimate projections for Victoria at 2040 and 2065. Canberra: CSIRO; 2016. https://doi.org/10.4225/08/5892224490e71



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