High-resolution projections of surface water availability for Tasmania, Australia
Other literature type
Bennett, J. C.
Ling, F. L. N.
Post, D. A.
Grose, M. R.
Corney, S. P.
Holz, G. K.
Katzfey, J. J.
Bindoff, N. L.
(issn: 1607-7938, eissn: 1607-7938)
Changes to streamflows caused by climate change may have major impacts on
the management of water for hydro-electricity generation and agriculture in
Tasmania, Australia. We describe changes to Tasmanian surface water
availability from 1961–1990 to 2070–2099 using high-resolution
simulations. Six fine-scale (∼10 km<sup>2</sup>) simulations of daily
rainfall and potential evapotranspiration are generated with the CSIRO
Conformal Cubic Atmospheric Model (CCAM), a variable-resolution regional
climate model (RCM). These variables are bias-corrected with quantile
mapping and used as direct inputs to the hydrological models AWBM, IHACRES,
Sacramento, SIMHYD and SMAR-G to project streamflows.
The performance of the hydrological models is assessed against 86 streamflow
gauges across Tasmania. The SIMHYD model is the least biased (median bias = −3%)
while IHACRES has the largest bias (median bias = −22%). We find
the hydrological models that best simulate observed streamflows produce
similar streamflow projections.
There is much greater variation in projections between RCM simulations than
between hydrological models. Marked decreases of up to 30% are projected
for annual runoff in central Tasmania, while runoff is generally projected
to increase in the east. Daily streamflow variability is projected to
increase for most of Tasmania, consistent with increases in rainfall
intensity. Inter-annual variability of streamflows is projected to increase
across most of Tasmania.
This is the first major Australian study to use high-resolution
bias-corrected rainfall and potential evapotranspiration projections as
direct inputs to hydrological models. Our study shows that these simulations
are capable of producing realistic streamflows, allowing for increased
confidence in assessing future changes to surface water variability.