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Resilient urban systems:
a socio-technical study of community scale climate change adaptation initiatives
4.4.2
Projected climate hazards
This section looks at the sorts of climate hazards that may test the resilience of the systems, which includes
householders and communities.
If we accept broad assumptions around ongoing community demand for energy and water services, Aurora
and WestWyck are likely to be affected by the same ‘primary’ (direct, physical) on-site and off-site impacts
of climate change. Both developments rely on the same catchment water supplies and lie within a climatic
region likely to experience higher peak and average temperatures, shifts to increased rainfall intensity, and
lower rainfall overall (CSIRO and Bureau of Meteorology, 2007). Some variability between the sites may be
experienced due to WestWyck’s location within inner Melbourne suburbs (e.g. night-time temperatures
during heatwaves may be higher) and Aurora’s location further inland (e.g. average and peak temperatures
may be higher and rainfall lower).
The primary on-site climate related impacts at both sites are likely to be caused by drought and heatwaves.
Off-site impacts are most likely to be caused by drought and secondary climate change impacts - blackouts
and catchment fires.
Drought:
Based on stakeholder interviews, on-site impacts of drought have been relatively limited and
included reductions in on-site rainwater collection (at WestWyck) and increasing demand for water for
irrigation (at both sites) (S1; S2; S3; S4; S14). While the recent drought and subsequent water restrictions
last decade had no impact on recycled water system functions at either site, more severe or prolonged
droughts could potentially affect all water system functions by forcing a major rationing of potable water
supply
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.
Heatwaves:
Periods of high temperature were reported to affect the provision of hot water services (causing
hot water systems to fail or leak at Aurora) and, according to some interviewed householders, reduced
comfort in certain parts of homes at both developments (A1; A5; A6; A11; A13; W2; W6). While the hot
water system faults can be resolved directly, increased heatwave frequency poses a potential problem for
residents reliant on passive thermal design elements to maintain desired comfort levels.
Blackouts:
As identified by interviewed residents and institutional stakeholders at both developments,
off-site blackouts pose a temporary threat (in the order of hours to 1-2 days no more than once or twice a
year) to system functions reliant on electricity. These include all non-potable water supplies, pumping and
treatment functions. Blackouts pose a particular challenge to system functions because they often occur
without notice. Blackouts pose no risk to gravity-fed rainwater (at WestWyck) and pressurised (mains)
potable water supplies.
Bushfires:
Fires pose no direct on-site risk to either development. However, upstream, they can
contaminate Melbourne’s forested water catchments (Lane et al., 2008, Wilkinson et al., 2007), and
smoke can trigger distribution lines to shut down posing indirect risks to the security of mains water and
electricity supplies. The risks posed by fires to both developments depend on a range of factors including
their intensity and timing, which catchments are affected, the use of fire retardants, whether water supplies
are already low, and capacity for treatment. Availability of water from desalination might also play a role in
reducing supply disruption impacts from fire-related water contamination.
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The impact of drought on Melbourne communities connected to the mains water will also depend on the availability of
water from the Wonthaggi desalination plant.